E-Posters

Yusuke Oshita 1 , Shu Takahashi 2 , Soji Tani 3 , Kazumichi Yagura 2 , Haruka Emori 1 , Chikara Hayakawa 4 , Ryo Yamamura 4 , Kazuyuki Segami 2 , Ichiro Okano 3 , Toshiyuki Shirahata 5 , Koji Kanzaki 2 , Tomoaki Toyone 3 , Yoshifumi Kudo 3 1 Showa University Northern Yokohama Hospital, Yokohama, Japan , 2 Showa University Fujigaoka Hospital, Yokohama, Japan , 3 Showa University Hospital, Tokyo, Japan , 4 Showa University Hospital, To, Japan , 5 Showa University Koto Toyosu Hospital, Tokyo, Japan Introduction: The presence of an intervertebral disc High intensity zone (HIZ) has been noted as a cause of low back pain. There are reports that the prevalence of HIZ varies by sport, but there are no detailed reports on rugby players. The purpose of this study was the prevalence of HIZ and its positional relationship based on pre-season medical checkups of the elite college rugby team. Material and Methods: We retrospectively reviewed lumbar spine MRI findings at the time of medical checks in 88 elite college rugby players performed in 2023. Results: Average height and weight were 173.9 (range:197.5 - 160.0) cm and 84.8 (range:113.0 - 61.7) kg. The mean age was 20 (Range: 18-22) years. Forwards (FW) accounted for 44 positions: prop (PR) in 12 cases, hooker (HO) in 8 cases, lock (LO) in 10 cases, flanker (FL) in 9 cases, number 8 (No.8) in 3 cases, and 1 case each of PR, HO, FL and No.8. Backs (BK) accounted for 44 cases, 9 as scrum half (SH), 5 as standoff (SO), 11 as center (CTB), 13 as wing (WTB), 3 as full back (FB), and 1 each as CTB and WTB, SO and FB, and WTB and FB. 12 (13.6 %) of the 88 players had HIZ within the bulging disc. 1 player had HIZ in 2 discs. Seven patients had L4/5, four had L5/S, and one had L3/4 and L4/5 in two locations. In FW, 5 cases of PR, one case of HO, LO, and FL were present; and in BK, one SH was present and CTB in two cases. Six of the 12 HIZ holders in the entire team were in the first row (PR and HO) of FW position, and 28.6% (6/21) of the students in those positions had HIZ. None of the students had back pain exacerbations that required surgery during the season, but some of them did require time off due to back pain. Although all players in a rugby team engage in moves that require physical contact, such as tackles, the eight forward players especially in first low are more likely to be involved in contact situations, such as scrums, mauls, and rucks, which exert greater stress on the spine. These conditions indicate that forward players, who are more likely to engage in frequent physical contact, may have more advanced degrees of disc degeneration than those of back players. Such physical stress is a major contributor to advanced disc degeneration in forward players. Conclusion: Among elite college rugby players,13.6% of college rugby players had HIZ, half of them in the first row FW position. 28.6% of FW first row players had HIZ. In terms of rugby field positions, degeneration was more advanced in forward players than in back players. However, further research is required to predict and prevent sports-related injuries. Sathish Muthu 1,2,3 1 Government Karur Medical College, Department of Orthopaedics, Karur, India , 2 Karpagam Academy of Higher Education, Department of Biotechnology, Coimbatore, India , 3 Orthopaedic Research Group, Coimbatore, India Introduction: Epidural steroid injection (ESI) is one of the key management strategies in the management of discogenic radicular pain. This study aims to compare the efficacy and safety of fluoroscopy-guided ESI through caudal epidural route and selective nerve root block (SNRB) techniques for L5-S1 discogenic unilateral radicular pain. Methods: This is a prospective non-randomized comparative study conducted between Jan 2023 and Jan 2024 in a tertiary care hospital that included patients presenting with L5-S1 discogenic unilateral radicular pain failing other conservative line of management for epidural steroid injection. The pain was analysed using a numerical pain rating scale from 0-100 at immediate post-injection, 2 weeks and 6 months duration. Treatment failure is defined as > 50% resurgence of baseline pain. Other outcomes analysed were the length of the procedure, and fluoroscopy shots used during the procedure. Results: We enrolled 18 patients with L5-S1 discogenic unilateral radicular pain for caudal ESI (cESI) (M: F 12:6) with a mean age of 32.43 ± 11.6 years and 12 patients for SNRB (M: F 4:8) with a mean age of 38.21 ± 9.2 years. A significant decrease in pain following the procedure was noted at all time points compared to the baseline (p < 0.001) for both techniques. The SNRB group experienced significantly more failures at 6 months compared to the cESI group (p = 0.001). Further, the SNRB group had significantly longer procedure time (p < 0.001), and fluoroscopy shot usage (p < 0.001). No major adverse events were reported for either of the procedures. Conclusion: cESI is a simple, safe and efficacious technique compared to SNRB in the management of L5-S1 discogenic unilateral radicular pain. Meddeb Mehdi 1 , Safouen Ben Brahim 1 , Hachicha Hassan 1 , Yahia Aissaoui 1 , Hassen Makhlouf 1 , Mondher Mestiri 1 1 Kassab Institute, Adults, Manouba, Tunisia Introduction: The L5-S1 disc plays a significant role in the therapeutic strategy for degenerative lumbar pathologies, especially during arthrodesis. It serves as a transitional zone between the mobile lower lumbar spine and the immobile sacral region. The management of this disc in revision surgeries for degenerative lumbar pathology remains a highly debated topic today. The purpose of our study is to assess the medium-term radiological and functional outcomes and to identify the risk factors associated with L5-S1 disc degeneration following lumbar arthrodesis. Material and Methods: This is a descriptive retrospective study conducted on 53 patient records who were both followed and operated on for degenerative lumbar pathology. These patients were selected from the database of our department over a five-year period, from 2013 to 2018. Results: The average age was 70.67 years, with a male-to-female ratio of 0.5. Obesity was present in 83.3% of the patients, and 9% had hypertension (HTA). The ODI (Oswestry Disability Index) score was 33.08% ± 8% among patients who developed disc degeneration compared to 23% ± 8% in the entire series. Among our patients who developed L5-S1 disc degeneration after fusion, 50% had a posterior lumbar interbody fusion (AGPL) at L2-L5, 25% had AGPL at L3-L5, and 25% had circumferential fusion. The adjacent segment syndrome at L5-S1 was more common in older, obese, sedentary, and hypertensive patients, with statistically significant differences. The length of the fusion was correlated with statistically significant disc degeneration (p = 0.0003), as was postoperative lumbar lordosis, favoring hypo-lordotic spines (p = 0.0472). Conclusion: The adjacent segment disease (ASD) at L5-S1 following lumbar arthrodesis that spares the L5-S1 disc is a medium to long-term surgical complication. Including this level in the fusion requires a careful analysis of various risk factors due to its asymptomatic survival. This adjacent segment disease can be limited through proper correction of lumbar lordosis. Xiaolong Chen 1 , Dongfan Wang 1 , Zheng Wang 1 , Peng Cui 1 , Shibao Lu 1 1 Xuanwu Hospital Capital Medical University, Beijing, China Introduction: Recent studies have provided evidence that structural changes in paraspinal muscles are associated with intervertebral disc degeneration (IDD), ubiquitous with low back pain (LBP), and potentially thought to be regulated by inflammatory processes. However, the links remain unclear. The aims of this study were to investigate structural changes in paraspinal muscles that differed in healthy and lumbar disc herniation (LDH) patients, and LDH patients with and without LBP, and to determine the link with the expression of inflammatory marker(s). Material and Methods: Cross-sectional areas (CSAs) and fatty degeneration of muscles were measured in this prospective cohort study. Multifidus muscle (MM) tissue was procured from included individuals undergoing surgery. Gene expression was quantified using qPCR assays. Independent t-test, Chi-square, and Spearman correlation were used for evaluating the links among structural changes, expression of inflammatory markers, and clinical outcomes. Results: Functional CSA and fatty degeneration of MM were larger in healthy group than LDH group. A significant increase in fat infiltration in MM in LBP group than in non-LBP group. TNF-alpha (TNF-α) was 28-fold greater in high-fat infiltration group than low-fat infiltration group within MM. Expression of TNF-α and IL-1β in MM was moderately correlated with functional CSA and fatty degeneration of MM, which was moderately correlated with clinical outcomes. Conclusion: Results support the hypothesis that IDD is associated with dysregulation of inflammatory state of local MM, which provides initial evidence that inflammatory dysregulation in paraspinal muscles has the potential for a broad impact on tissue health and LBP symptoms. Keywords: Paraspinal muscle atrophy, fatty degeneration, inflammation, low back pain, lumbar disc herniation Perrine Coquelet 1,2 , Sara-Maude Boucher 1,2 , Sandra Da Cal 2 , Gilles El Hage 3 , Sung-Joo Yuh 2,3,4 , Daniel Shedid 2,3,4 , Nathalie Arbour 1,2 1 Université de Montréal, Neurosciences, Montreal, Canada , 2 Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Neurosciences, Montreal, Canada , 3 Centre Hospitalier de l'Université de Montréal (CHUM), Neurosurgery, Montreal, Canada , 4 Université de Montréal, Surgery, Division of Neurosurgery, Montreal, Canada Introduction: Degeneration of the intervertebral discs can lead to several pathologies associated with back pain. Degenerated discs show enhanced degradation of the extracellular matrix, nerve innervation, neovascularization, and infiltration of peripheral immune cells. The role of inflammation is increasingly recognized in the pathobiology of intervertebral disc degeneration (IDD) both locally (in discs) as well as in the periphery (e.g. blood). Metalloproteinases (MMP) have been implicated in disc extracellular matrix degeneration; however, inflammatory factors triggering such degradation are incompletely resolved. Moreover, altered blood levels of growth factors, inflammatory mediators, cytokines, and chemokines have been observed in IDD patients compared to controls. We recently identified plasma biomarkers predicting recovery at two months post-surgery for IDD patients. We reported that elevated CRP and low CCL22 plasma levels in pre-surgery samples combined with the age of the IDD patient could predict an incomplete two-month post-surgery recovery. In contrast, low CRP and high CCL22 plasma levels were associated with full recovery. We hypothesize that inflammatory peripheral molecules can penetrate the disc and participate in intervertebral disc degeneration. Material and Methods: Clinical data collected from the patient’s medical records include age, sex, pain measurements, imaging data and recovery assessment 2 months post-surgery. Peripheral blood mononuclear cells (PBMCs) were isolated from IDD patients before their spinal surgery and from age and sex matched healthy controls (HC). RNA was extracted from PBMCs and sequenced. A portion of the resected tissue was digested to isolate human disc cells. Expanded disc cells were treated with inflammatory molecules for 48h prior to collect supernatants and cell lysate for multiplex ELISA assessment. Conversely, disc cells were collected and assessed by flow cytometry for the expression of multiple proteins. Results: Analysis of the transcriptomic profile of PBMC from IDD patients identified several genes (ADM, P2RY1, SLC1A3, SPRY1) that were significantly more expressed than in PBMC from age/sex-matched HC. Primary cultures of human disc cells exposed to inflammatory factors (interferon-gamma, interleukin-1beta, tumor necrosis factor) produced higher amounts of MMP-1, 2, 3, 7, 10 13 than untreated cells. However, the levels of tissue inhibitors of MMP (TIMP), remain unchanged. CRP, leptin or IL-18 treatment increased the expression of cell adhesion molecules CD24 and CD54 (ICAM) by human disc cells. Expression of CD155, another adhesion molecule, was also enhanced upon CRP or IL-18 exposure. Finally, human disc cells exposed to CRP exhibited higher levels of HLA-ABC (MHC-I), a key molecule for CD8 T cell activation. The expression of some proteins (e.g. HLA-ABC) by discs cells appeared to be increased with the patient’s age. Conclusion: Peripheral immune cells from IDD patients exhibit a distinct transcriptomic signature compared to age/sex matched HC. Human disc cells exposed to inflammatory mediators increase their expression of proteins involved in extracellular matrix degradation, cell-cell contact, and activation of immune cells. A better understanding of the peripheral and local (intra disc) inflammatory responses in the context of IDD could identify innovative targets for additional therapeutic options. Tainan Gomes Ferreira 1 , Djalma de Campos Gonçalves Júnior 1 , Igor Bueno Garrido 1 , Gabriel Kwiatkoski 1 , Cezar Kabbach Calaça Prigenzi 2 , Caio Cezar Nuto Leite França 2 , Carlos Roberto Massella Junior 3 1 Universidade Nove de Julho, São Paulo, Brazil , 2 Conjunto Hospitalar Mandaqui, São Paulo, Brazil , 3 Instituto Tratar, São Paulo Introduction: The innervation of the intervertebral disc (IVD) plays a crucial role in low back pain (LBP), particularly in cases of degenerative disc disease (DDD). This article reviews the latest evidence on the innervation of healthy and degenerated discs, focusing on nociceptive receptors and their implications in discogenic pain. In degenerated discs, significant neurovascular remodeling occurs, allowing the penetration of nociceptive nerve fibers into the nucleus pulposus, exacerbating chronic LBP. Understanding these mechanisms offers new perspectives for therapeutic interventions, aiming to modulate innervation and nociceptive activity. Material and Methods: A comprehensive literature review was conducted in PubMed using the following keywords: disc herniation, discogenic pain, substance P, and pain receptors. Results: The innervation of the intervertebral disc (IVD) plays a fundamental role in the pathophysiology of low back pain (LBP), particularly in patients with degenerative disc disease (DDD). This study reviews the most recent evidence on the innervation of healthy and degenerated IVDs, focusing on nociceptive receptors and their clinical implications in discogenic pain. In healthy IVDs, innervation is primarily limited to the outer layer of the annulus fibrosus (AF), with minimal penetration of nerve fibers into the nucleus pulposus (NP). These fibers are mostly of sensory and sympathetic origin, with low nociceptive activity. However, degenerated discs exhibit significant neurovascular remodeling, allowing deeper penetration of nociceptive fibers into the NP, exacerbating symptoms of chronic LBP. Recent studies, such as those by Groh et al. (2024) and García-Cosamalón et al. (2010), highlight increased expression of neurotrophins, including nerve growth factor (NGF) and pleiotrophin, as facilitators of aberrant nociceptive nerve growth in degenerated discs. Furthermore, receptors such as substance P and calcitonin gene-related peptide (CGRP) are upregulated in degenerated discs, contributing to neurogenic inflammation and the heightened perception of discogenic pain, as demonstrated by Mashaghi et al. (2016). This increase in neuropeptides and neurotrophic factors is strongly correlated with intensified nociception in DDD. Conclusion: Abnormal innervation and increased nociceptive activity are key elements in the progression of discogenic pain associated with DDD. A deeper understanding of these neurobiological mechanisms opens new avenues for innovative therapeutic interventions, focusing on modulating discal innervation and blocking nociceptive activity. Future therapeutic approaches may include the use of neurotrophin antagonists such as NGF and substance P, as well as targeted neural block therapies to inhibit neurovascular remodeling in the IVD. These strategies have the potential to revolutionize the clinical management of chronic LBP related to DDD, offering less invasive and more effective alternatives for patients. Majdi Ben Romdhane 1 , Maher Ben Thaer 1 , Majdi Sghaier 1 , Haithem Kamoun 1 , Rafik Elafrem 1 1 hopital FSI LA Marsa, Lamarsa, Tunisia Introduction: Symptomatic disc herniation is a common pathology, especially in young athletes, and can sometimes become disabling, leading to cessation of sporting activity and even professional reclassification. Surgical treatment should relieve the symptomatology and enable a return to normal daily activity. The aim of our study is to evaluate the postoperative results in our series in order to predefine the failure factors. Material and Methods: We reviewed the results of 50 patients who underwent surgery for symptomatic disc herniation between 2017 and 2020 at Tunis internal security forces hospital with a minimal follow up of 4 years. Our evaluation was built essentially on patient satisfaction, hernia recurrence (clinical and imaging) and analgesic consumption. Results: Our study includes 50 patients. The average follow-up is 4 years (range 3 to 7). The average age is 41 years. 40% of patients are smokers. The average BMI was 28.27. Radicular pain is found in 62% spinal stiffness is found in 70%. An incomplete sensory-motor deficit was seen in 2% of the cases there was no cauda equina syndrome. All patients had an MRI before surgery, 26% had a spine CT scan muscle fatty degeneration (Goutallier equivalent 1 and 2) noted in 50% of cases. Narrow lumbar canal was described in 26% of the cases. All patients have undergone open surgery. The outcomes are considered good to very good in 86% with 14% recurrence of lumbosciatalagy. The average return to work is 2 months. 42% required laminectomy 26% fusion and 36% discectomy. Daily consumption of painkillers were found in 14%. The re-operative rate (including recurrent disc herniation and fusion for degenerative indications) is 8% at the last follow-up. Conclusion: Almost 80% of subjects maintained good results at the last follow up. The use of instrumentation is minimal, especially in a young population, in order to allow mobility. A simple herniectomy has given good results, without overlooking the important role of physiotherapy in optimal management. Sami Bahroun 1 , Anis Bouaziz 1 , Mohamed Samih Kacem 1 , Masmoudi Zied 1 , Mohamed Samir Daghfous 1 1 Kassab Hospital, Orthopaedic Department B, Tunis, Tunisia Background: Initial management of lumbosciatica secondary to lumbar disc herniation is primarily conservative, focusing on medical treatment and physical therapy. However, the persistence of symptoms despite well-conducted conservative treatment presents a clinical challenge, often necessitating surgical intervention. There is ongoing controversy regarding the timing and necessity of surgery in such cases. When conservative management fails and symptoms persist, simple discectomy with posterior decompression can offer an effective and definitive solution for symptom relief. Materials and Methods: This retrospective descriptive study included patients with persistent sciatica due to lumbar disc herniation, with lumbosciatic pain persisting beyond 3 weeks of well-conducted medical treatment, and no history of intradural corticosteroid infiltration. Patients showing partial improvement or having undergone other interventional treatments were excluded. The surgical intervention consisted of a simple discectomy and posterior decompression. Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) and lumbar and radicular Visual Analog Scale (VAS) preoperatively and at the last follow-up. Postoperative neurological complications and recurrence of pain were also recorded. Results: A total of 26 patients were included, with a mean age of 38.54 ± 8 years (18 men, 8 women), and an average follow-up duration of 6.8 months. The L5-S1 level was affected in 16 patients, and the L4-L5 level in 10 patients. Preoperative scores were: ODI: 45.68, VAS lumbar: 6.8, and VAS radicular: 8.78. Postoperative scores showed significant improvement, with ODI: 16.35, VAS lumbar: 1.3, and VAS radicular: 1.45. No early postoperative neurological complications were reported. However, 3 patients experienced a recurrence of symptoms, and 2 developed chronic low back pain related to disc degeneration. Conclusion: Discectomy for persistent sciatica due to lumbar disc herniation provides significant clinical improvement in terms of pain reduction and functional outcomes. While early postoperative complications were minimal, a small percentage of patients experienced symptom recurrence or chronic low back pain, underscoring the need for long-term follow-up. Andres Bonilla 1 , Jeremiah Easley 1 1 Colorado State University, Clinical Sciences, Fort Collins, United States Introduction: Developing effective therapeutic strategies for intervertebral disc degeneration (IDD) remains a crucial focus of global research. However, progress in translating these therapies to clinical use is limited by the lack of a preclinical animal model that reliably evaluates their safety and efficacy. Sheep are particularly valuable for this research due to their close cellular, anatomical, physiological, histological, and molecular resemblance to humans in the context of IDD. Models involving cervical and lumbar intervertebral discs (IVDs) in sheep have been instrumental in advancing potential treatments. Despite this, a thorough understanding of the clinical and molecular distinctions between cervical and lumbar disc models is still lacking. This study aims to bridge this gap by comparing the clinical, surgical, imaging, histological, and proteomic features of induced cervical and lumbar IDD models in a large animal. Material and Methods: Six skeletally mature sheep were included in this study to evaluate and compare the progression of IDD following partial discectomy at the C2-3, C3-4, C4-5, L2-L3, L3-L4, and L4-L5 IVDs. Surgical approach was performed ventrally for the cervical discs and laterally for the lumbar discs. MRI scans were performed before surgery and at 8-, 16-, and 32-weeks post-surgery to monitor disc degeneration. Two independent, blinded observers analyzed the MRI images to evaluate the Disc Height Index (DHI) and Pfirrmann scores. Animals were humanely euthanized at 8 weeks (n=3) and 32 weeks (n=3). Post-mortem, digital images of the dissected cervical and lumbar discs at C2-3 and L2-L3 were taken. The C4-5 and L4-5 IVDs were processed for histological analysis. Additionally, tissue samples from the nucleus pulposus (NP) and annulus fibrosus (AF) of C3-4 and L3-4 discs were processed for proteomic analysis via mass spectrometry. Results: All animals recovered without complications following the surgical procedures. Clinically, no abnormalities or differences were observed between the two approaches. Imaging evaluations demonstrated statistically significant differences in DHI across all time points for both cervical and lumbar discs. Similarly, Pfirrmann scores indicated a progressive increase in the degree of IDD over time following partial discectomy for both regions. However, no statistically significant differences were observed when comparing cervical and lumbar discs at the same time points. Gross examination revealed notable morphological distinctions between the cervical and lumbar intervertebral discs at 8 and 32 weeks post-partial discectomy. Differentially expressed protein analysis showed significant variations between cervical and lumbar IVDs when comparing healthy/naïve samples with those taken at 8 and 32 weeks post-surgery. Histological evaluation revealed similar patterns of degeneration between cervical and lumbar IVDs. Conclusion: Our findings demonstrate that the cervical intervertebral disc degeneration model in sheep reliably replicates the established lumbar model, further validating the ovine model as a robust and adaptable preclinical platform for studying IDD. This consistency across both spinal regions underscores the utility of the sheep model for preclinical research, offering a dependable framework for evaluating therapeutic interventions targeting cervical and lumbar disc degeneration. These results pave the way for future studies aimed at refining and developing treatment strategies for successful clinical application. François Dantas 1 , Igor Loureiro 2 , Marco Tulio Reis 2 , Bárbara Campos Mattos 2 , Victor Kelles Tupy Da Fonseca Fonseca 3 , Fernando Luiz Dantas 4 1 Krembil Neuroscience/ Western Hospital, Neurosurgery, Biocor Instituto, Toronto, Canada , 2 Biocor/Rede D'Or Hospital, Neurosurgery, Belo Horizonte, Brazil, 3 Post-graduation Faculdade de Ciências Médicas de Minas Gerais, Post-Graduation, Belo Horizonte, Brazil, 4 Post-graduation Faculdade de Ciências Médicas de Minas Gerais, Neurosurgery, Biocor Instituto, Belo Horizonte, Brazil Introduction: Thoracic disc herniation is a rare spinal condition that can cause pain, paresthesia, and paresis due to pressure on the spinal nerves. It accounts for 0.1 to 3% of disc herniations, occurring mainly below T7-T8. The incidence is approximately 3.5 cases per 100,000 people, affecting more men and increasing with age. The condition can significantly impair the quality of life of patients. The present study aims to analyze the clinical outcomes of patients undergoing surgery for thoracic disc herniation correction in a private hospital in Belo Horizonte, Minas Gerais. Methods: This case series study analyzed patients who underwent thoracic discectomy at private institution between 2018 and 2023. Patients aged ≥ 18 years with complete clinical data were included. Demographic, pre- and post-surgical clinical information, radiological aspects, surgical technique, hernia level, Nurick scale score, postsurgical evolution, and complications were collected. Statistical analysis used Excel Office 2010 and third-party tools, with a significance level of 5% and a 95% confidence interval. Eigthen patients were evaluated (mean age 56.7 years, 55,5%men). Main symptoms: paraparesis (47%), worsening of gait (29.4%), altered sensitivity (17.6%) and chest pain (29.4%). Calcified disc herniation was present in 24%. The most affected level was T11-T12 in 22.2%. The access was thoracotomy in fifteen cases and three were transpedicular. Complications occurred in 16,6% of cases. Complete or partial improvements were observed in 83,3% of patients. Conclusion: Most patients showed significant improvement after thoracic discectomy, with a low complication rate. These results are consistent with the existing literature, suggesting the efficacy of surgery in relieving symptoms and improving quality of life. Additional studies with larger sample sizes are needed to confirm these findings.

Julius Gerstmeyer 1,2,3 , Anna Gorbacheva 2 , Clifford Pierre 1 , Donald Davis 1,2 , Tara Heffernan 2 , Luke Jouppi 2 , Periklis Godolias 4 , Thomas Schildhauer 3 , Amir Abdul-Jabbar 1,2 , Rod Oskouian 1,2 , Jens Chapman 1,2 1 Swedish Neuroscience Institute, Seattle, United States , 2 Seattle Science Foundation, Seattle, United States , 3 BG University Hospital Bergmannsheil, Department of General and Trauma Surgery, Bochum, Germany , 4 St. Josef Hospital Essen-Werden, Department of Orthopedics and Trauma Surgery, Essen, Germany Summary of Background Data: Spine surgery represents a dynamic and innovative specialty with a steady increase in annual publications since 1900. The introduction of large databases and registries marked a paradigm shift allowing researchers to affordably analyze and interpret vast heterogeneous samples of data in a time- and cost-efficient manner. However, despite its quantitative superiority, databases in research are inherently limited in a number of ways. Spine remains a somewhat controversial specialty with significant cost, population health, and outcomes implications and has not surprisingly become more frequently associated with large-scale registry studies. The aim of this study was to identify usage of large databases in spine surgery research and its evolution over time, representing shifts in clinical focus changes. Methods: A database search in the Clarivate Analytics Web of Science (WoS) database was conducted on July 3, 2024. Keywords included (“big data” OR “large database” OR “registry” OR “national database”) AND “spine surgery”. Articles were categorized using a semiautomated protocol based on the primary stated objective, into seven categories. A descriptive and quantitative analysis was performed. Results: A total of 630 articles spanning the years 1993 to 2023 were extracted. The most frequent category was degenerative, with 182. Overall the number of database-generated spine publications increased greater than ten-fold from 2012 to 2023. The United States accounted for the most publications (63.97%). The citation analysis showed a constant increase in numbers, from 155 citations in 2012 to 2062 in 2023. Conclusion: The use of large databases, paraphrased as “BIG DATA”, in spine surgery research has substantially increased over the past decades. The trend analysis showed a growing representation in the categories of infection and public health/outcomes , whereas degenerative and tumor topics remained relatively constant. Our study also confirms a growing utilization of large database studies pertaining to spine surgery research. Sunil Chodavadiya 1 1 Bombay Hospital, Orthopaedics, Mumbai, India Study Design: Comparative retrospective analysis. Introduction: Spine surgery in elderly patients presents distinct challenges due to age-related physiological changes and multiple comorbidities. The selection of an anaesthetic method - whether spinal or general anaesthesia - can greatly influence perioperative outcomes and overall safety. Objective: This retrospective analysis aimed to assess the safety of different anaesthetic approaches in geriatric patients undergoing spine surgery, comparing outcomes between spinal anaesthesia and general anaesthesia. Methods: A total of 140 geriatric patients (aged 65 years and above) who underwent spine surgery were included in this study. Patients were divided into two groups based on the type of anaesthesia received: the spinal anaesthesia group (n = 70) and the general anaesthesia group (n = 70). Data on perioperative complications, postoperative pain management, length of hospital stay, and patient satisfaction were collected retrospectively from electronic medical records. Results: Both groups were similar in demographic characteristics and preoperative comorbidities. The incidence of perioperative complications, including intraoperative hypotension, postoperative nausea and vomiting, and urinary retention, was lower in the spinal anaesthesia group compared to the general anaesthesia group (p < 0.05). Postoperative pain scores were significantly lower in the spinal anaesthesia group at various time points compared to the general anaesthesia group (p 0.05). Patient satisfaction scores were higher in the spinal anaesthesia group compared to the general anaesthesia group (p < 0.05). Conclusion: Spinal anaesthesia appears to offer a safer anaesthetic approach in geriatric patients undergoing spine surgery, with lower perioperative complications, improved postoperative pain management, and higher patient satisfaction compared to general anaesthesia. These findings underscore the importance of prioritizing safety considerations when selecting anaesthetic approaches for spine surgery in the geriatric population. Hirokazu Inoue 1 , Atsushi Kimura 1 , Katsushi Takeshita 1 1 Jichi Medical University, Shimotsuke, Japan Introduction: With the increase in the elderly population, the number of patients with osteoporosis has increased, and the prevalence of thoracolumbar compression fractures (VCF) and hip fractures due to falls has increased. Decreased lower leg muscle mass and grip strength are also risk factors for the development of VCF and may be closely related to the pathogenesis of sarcopenia. Handgrip strength (HGS) is used in many studies to predict patient pathology because it is easy to measure and useful. The purpose of this study was to evaluate the relationship between body composition and grip strength in patients with VCF using bioelectrical impedance analysis. Material and Methods: A cross-sectional study at a single hospital was conducted and enrolled elderly patients diagnosed with VCF. In this study, low HGS (< 28 kg in male and < 18 kg in female) and gait speed < 1.0 m/s were defined as sarcopenia according to the 2019 Asian Working Group for Sarcopenia. A multifrequency validated bioelectrical impedance analyzer Inbody S10 (Biospace, Seoul, Korea) was used, with the patient in the supine position. Skeletal muscle mass and fat mass were also measured. The skeletal muscle mass index (SMI) was calculated by dividing the measured skeletal muscle mass by the square of the height in meters. Skeletal muscle mass, skeletal muscle mass index (SMI), total body water (TBW), intracellular water (ICW), extracellular water (ECW), and phase angle (PhA) of patients with thoracolumbar compression fractures were studied after admission using multi-frequency direct segment bioelectrical impedance analysis. Results: The study included 112 patients (26 males and 86 females, mean age 83.3 years) admitted with VCF. The prevalence of sarcopenia according to the 2019 Asian Working Group for Sarcopenia guidelines was 61.6%. HGS was significantly correlated with right upper limb muscle mass (p < 0.001, r = 0.684), left upper limb muscle mass (p < 0.001, r = 0.622), trunk muscle mass (p < 0.001, r = 0.655), right lower limb muscle mass (p < 0.001, r = 0.692), left lower limb muscle mass (p < 0.001, r = 0.673), ICW (p < 0.001, r = 0.500), ECW (p < 0.001, r = 0.569), TBW (p < 0.001, r = 0.543), SMI (p < 0.001, r = 0.629), ECW/TBW (p < 0.001, r = -0.498), and PhA (p < 0.001, r = 0.550). Conclusion: In the current study, we found that HGS was related to PhA, and ECW/TBW ratio in patients with VCF. “Edema index” is calculated as the ratio of extracellular water to total body water (ECW/TBW). A previous study demonstrated that ECW/TBW, as a combination of overhydration and protein-energy wasting, may be a significant predictor of poorer outcomes. Lower HGS may be a predictive factor for poor outcomes after VCF. However, the present study had several limitations. First, patients were retrospectively surveyed at a single institution. Second, the cross-sectional design limits drawing any causal relationships. Finally, male patients with VCF were small. Anton Denisov 1 1 Hospital CEMTRO, Madrid, Spain The lecture will tell about systematic errors that were observed by author reviewing the recent literature about anterior approach and their complications preparing systematic review. It was observed that there is a lack of proper interpretation of the statistical analysis, that lead to misunderstanding interpretations. It will be tried to systemize common mistakes and their solutions. The author possess the diploma of magister of biostatistics and work as spinal surgeon that give an opportunity to revise the must important part of studies, methodology and proper interpretation of the results. This lecture may be included as extra part for AO spine committee meeting Kunal Chanji 1 , Sajan Hegde 1 , Appaji Krishnan 1 , Vignesh Badikillaya 1 , Harith Reddy 1 , Sharan Achar Thala 1 , Akshya Raj 1 , Sakthivel Ramaswamy 1 1 Apollo Hospitals, Spine Surgery, Chennai, India Introduction: Spontaneous epidural hematoma of the spine (SEHS) is an incredibly uncommon entity. Jackson described the first case, which involved a 14-year-old girl, in 1869. Since then, many cases have been described in the literature. Usually, a slight barotrauma like a cough causes the postero-internal vertebral venous plexus to burst. There is usually blood collection in the extradural space compressing the anterior part of the medulla. SEHS most frequently affects the cervico-dorsal or dorsal spine. The epidural hematoma can be associated with provocative factors such as anticoagulant or anti-aggregating drugs, minor trauma, peridural catheter insertion, severe cough, or extreme effort such as delivery. It can also be secondary to an arterio-venous malformation, a cavernoma, or a vertebral haemangioma. Any patient receiving anticoagulant drugs who complains of radiculopathy or myelopathy should be suspected of having a spontaneous spinal epidural hematoma. While laminectomy is the primary method of surgically removing the spinal epidural hematoma, conservative measures may be used in rare instances where the patient is healing steadily and quickly. Material and Methods: A case report of 61-year-old female patient presented with neck pain radiating to right upper extremity with numbness and tingling for 15 days. The pain was moderately severe. The patient had no history of constitutional symptoms and no history of any trauma. Patient was a diabetic, hypertensive and hypothyroid patient with a history of coronary artery disease on Tab Rivaroxaban for 1 year. On physical examination, the patient was conscious and well oriented. She had no neurological deficits. The blood workup was normal with a normal INR. Patient had gone to a local hospital where MRI was done and patient was told she has a tumor in her cervical spine. Results: A repeat cervical MRI was done 3 days after the first MRI which revealed a focal extra dural lesion involving C2-C4 vertebral levels along the dorsolateral aspect of right-side indenting cord with no compression. The size of the lesion in new MRI was decreased, hence the hematoma was assumed to be resolving and patient was managed conservatively with close observation. Patient reported complete resolution of symptoms in 10 days. Conclusion: Non-traumatic hematomas of the spine are extremely rare and can lead to serious neurological sequelae. Severe pain followed by progressive neurological deficit is the major symptom that should alert the treating physician on the possible diagnosis of SEHS. Rarely patient present with milder symptoms. MRI is the gold standard to confirm the presence and the extent of the hematoma. Early diagnosis and urgent decompression are essential to decrease the neurological sequelae. In patients with resolving hematoma with no neurological deficits conservative treatment can be opted with close neurological surveillance. Wièm Mansour 1 , Ghassen Gader 1 , Hdhili Houssem 1 , Bahri Farah 1 , Aziz Bedioui 1 , Mohamed Zouaghi 1 , Mouna Rkhami 1 , Mohamed Badri 1 , Kamel Bahri 1 , Zammel Ihsen 1 1 Trauma and Burns Center, Department of Neurosurgery, Ben Arous, Tunisia Introduction: Lumbar sciatica is a frequent reason for neurosurgical consultations and a significant cause of work absenteeism. While medical treatment is the first line of management, surgery is considered for cases with severe pain and a clear correlation with imaging findings. Epidural corticosteroid injections provide a useful alternative in situations where the relationship between clinical symptoms and radiological findings is unclear. Patients and Methods: A retrospective study was conducted, collecting 15 cases of lumbar sciatica over a period of 3 years (2019-2022). The objective was to assess the effectiveness of epidural injections in the management of lumbar sciatica. Results: The study included 6 men and 9 women with an average age of 42.3 years (range: 25-58 years). Sciatica was L5 in 8 cases, S1 in 5 cases, and bi-radicular in 2 cases. All patients had mechanical pain, with bilateral symptoms in 6 patients. The average duration of sciatica was 3 years. Spinal stiffness was noted in 9 patients. The Lasègue sign was positive in 12 cases, while the bell sign was present in 9 cases. Discogenic causes were the primary etiology of sciatica in 86% of patients. Non-discogenic causes included posterior facet joint arthrosis, spondylolisthesis, and, less frequently, isthmic spondylolysis and Tarlov cysts. After failing a well-managed medical treatment, all patients received blind epidural injections. Early follow-up showed a good outcome in 78% of cases, with a satisfactory outcome in 70% of cases at 3 months. Conclusion: Lumbar sciatica is a highly prevalent condition with significant socio-economic impact. Various preventive and therapeutic approaches are available for treating sciatica. Epidural injections continue to play a role in the management of this condition. Wièm Mansour 1 , Ghassen Gader 1 , Mohamed Chabaane 2 , Bahri Farah 1 , Hdhili Houssem 1 , Aziz Bedioui 1 , Mohamed Zouaghi 1 , Mouna Rkhami 1 , Mohamed Badri 1 , Kamel Bahri 1 , Zammel Ihsen 1 1 Trauma and Burns Center, Department of Neurosurgery, Ben Arous, Tunisia , 2 Sahloul Hospital, Department of Neurosurgery, Sousse, Tunisia Introduction: Spinal arachnoid cysts are uncommon, representing approximately 1% of all spinal lesions. Although they are often asymptomatic, these cysts can cause neurological symptoms by compressing the spinal cord, cauda equina, or nerve roots. Fortunately, spinal arachnoid cysts are treatable with surgery. We present our experience in managing spinal arachnoid cysts, based on a study of 13 patients. Methods: This retrospective study examines 13 patients treated for spinal arachnoid cysts between 2015 and 2022 in our department of neurosurgery. Patients with post-traumatic arachnoid cysts were excluded from the study. All patients underwent spinal MRI, with three of them also having computed myelography. Twelve patients underwent surgery. Surgical techniques included various approaches such as cyst excision, cyst shunt placement, or cyst puncture. Results: The mean age for our patients was 36 years, with extremes ranging between 4 and 69 years old. 10 of our patients were women with a sex ratio female/male at 3, 33/1. All our patients were symptomatic. Gait disturbances were the most represented functional sign (69%), followed by sphincter disturbances (53%) and ridiculer pain (30%). Among the cases, 3 (23%) presented with either radiculopathy or medullary claudication and back pain. Neurological examinations revealed paraparesis in 9 cases (69%) and lower limb dysesthesia in 4 cases (30%). MRI showed solitary arachnoid cyst in 12 cases. Only one patient presented 2 lumbar arachnoid cysts. The arachnoid cyst was epidural in 11 cases and intramedullary in 2 cases. All the cysts were posterior or posterolateral. All cysts had cerebrospinal intensity on T1 and T2 weighted images. The location of the cysts was Thoracic in 8 cases, Lumbar in 4 cases and cervico-thoracic in one case. Twelve patients underwent surgery, while one patient, an 8-year-old girl, was not surgically managed. She had developed lower limb weakness after scoliosis treatment with a brace. Imaging revealed a thoracic epidural arachnoid cyst, but removal of the brace led to significant improvement of her symptoms. Among the 10 patients who had total cyst excision after laminectomy, a single dural tear was identified in 10 cases and successfully closed. In one case, multiple dural defects were found and could not be closed; therefore, a shunt was placed between the cystic cavity and the subarachnoid space for this patient. Conclusions: Spinal arachnoid cysts, though rare and often asymptomatic, can cause significant neurological issues when they compress vital structures such as the spinal cord or nerve roots. Surgical intervention, including cyst excision, shunt placement, or puncture, proved effective in managing these cases. The majority of patients in our study experienced substantial improvement following surgery, with one case successfully managed conservatively. Overall, our experience underscores the importance of timely diagnosis and tailored surgical management in addressing spinal arachnoid cysts and improving patient outcomes. Junrui Jonathan Hai 1,2 , Weishi Liang 1,3 , Bo Han 1,4 , Xianjun Qu 1 , Yong Hai 1,3 1 Joint Laboratory for Research & Treatment of Spinal Cord Injury in Spinal Deformity, Laboratory for Clinical Medicine, Capital Medical University, Beijing, China , 2 Princeton International School of Mathematics and Science, Princeton, United States , 3 Beijing Chaoyang Hospital, Capital Medical University, Orthopedic Surgery, Beijing, China , 4 Beijing Jishuitan Hospital, Capital Medical University, Beijing, China Introduction: Distraction spinal cord injury (DSCI) is characterized by inflammation after scoliosis correction surgery, but there are no effective drugs in clinical use. This study aimed to evaluate the effects of rutin, a natural product, on DSCI, as well as the underlying mechanism was investigated. Material and Methods: Microglial cells were treated with rutin to assess its anti-inflammatory effects. In DSCI rats, rutin’s efficacy was evaluated through behavioral tests and tissue analysis and the mechanism of rutin therapy was investigated by mRNA sequencing of tissues. Results: In vitro cell-based results, rutin blocked the LPS-induced higher expression of inflammatory factor in microglial cells. In rat, BBB and ramp test scores were significantly decreased in DSCI rat, high-dose rutin (HRT) was more effective than low-dose rutin (LRT) in reducing inflammatory infiltration and neuronal apoptosis in DSCI tissues, and it also showed better improvement in microstructural demyelination. Transcriptomic differentially expressed genes (DEGs) analysis and KEGG pathway analysis and RT-qPCR validation of the top DEGs determined that MAPK13 was the key target gene. MAPK13 as a subunit of P38 MAPK suggests that P38 MAPK is the specific functional target. Molecular docking technology and immunohistochemistry indicated a potential interaction between rutin and P38 MAPK, supporting rutin’s anti-inflammatory effects. Rutin significantly reduced the activation levels of the P38 MAPK/NF-κB/STAT3 pathway, with HRT demonstrating even greater efficacy. Conclusion: Rutin reduces DSCI by inhibiting inflammation through downregulation of the P38 MAPK/NF-κB/STAT3 pathway. Rutin has potential as a treatment drug for DSCI in clinical applications. Keywords: Distraction spinal cord injury (DSCI); Rutin; inflammation; rat DSCI model; P38 MAPK/NF-κB/STAT3 pathway Renato Tavares 1 , João Guimarães 1 , Antonio Eulalio Pedrosa Araujo Junior 1 , Gustavo Azevedo 1 , Ana Beatriz Tavares 2 , Helton Defino 3 , Jamila Alessandra Perini 4 1 National Institute of Traumatology and Orthopedics (INTO), Spine Surgery Center, Rio de Janeiro, Brazil , 2 Rio de Janeiro state university (UERJ), Endocrinology, Medical clinic, Rio de Janeiro, Brazil , 3 University of São Paulo (USP), Spine surgery, Orthopaedic, Ribeirão Preto, Brazil , 4 Rio de Janeiro state university (UERJ), Pharmaceutical Sciences, Research Laboratory, Rio de Janeiro, Brazil Introduction: Vitamin D receptor (VDR) gene, a member of human transcription factors, mediates various biological effects and it has a critical key to normal bone remodeling and mineralization. Several genetic association studies have shown that the VDR gene is closely associated with the severity of the thoracic curve. Therefore, VDR polymorphism is considered as one of the candidates potentially related to the susceptibility of adolescent idiopathic scoliosis (AIS). The aim of this study was to evaluate the potential role of the rs731236 polymorphism in the VDR gene in the development and severity of AIS in a Brazilian female population. Material and Methods: A retrospective case-control study was performed in 175 AIS patients and 175 healthy controls recruited from a reference center of orthopedics in Brazil. Polymorphism was genotyped using a TaqMan validated assay. Associations were evaluated using a binary logistic regression model with odds ratios (OR) and 95% confidence intervals (CI). Results: The mean age and Cobb angle in the female AIS group were 17 ± 5.5 (10-30) years and 48.7 ± 16.6 (11-110) degrees, respectively. There was a predominance of Cobb ≥ 45° (57.1%), skeletally mature (Risser IV-V) (68.5%), and low or normal anthropometric measurements (78.8%). The VDR rs731236 polymorphism was in Hardy-Weinberg equilibrium in the whole population (n = 350, p = 0.28) and in both subgroups: controls (p = 0.15) and AIS cases (p = 0.83). The minor allele frequency of the polymorphism (A > G) was 35.7% and 40.4% in controls and AIS cases, respectively. VDR rs731236 allele (G) and genotype GG were associated with higher risk of AIS Cobb < 45° (OR = 1.5; 95% CI = 1.01-2.2 and OR = 2.7; 95% CI = 1.2-6.0, respectively). Conclusion: In a Brazilian female population, the VDR rs731236 polymorphism was associated with genetic susceptibility to AIS. The presence of the VDR rs731236 GG genotype variant suggests the possibility of a personalized clinical evaluation aimed at early detection of risk of AIS with Cobb < 45° to improve diagnosis and treatment, and even identify who are the cases that will not have curve progression.

Marcos Vaz De Lima 1,2 , Arthur Klein 3 , Priscila Fernandes 2 , Marco Moscatelli 4 , Antonio Roth Vargas 5 , Enrico Ioriatti 6 , Martin Komp 7 , Sebastian Ruetten 7 1 Santa Casa de São Paulo, Ortopedia e Traumatologia, São Paulo, Brazil , 2 Instituto Tecnológico de Aeronáutica - ITA, Bioengenharia, São José Dos Campos, Brazil , 3 Purdue, West Lafayette, United States , 4 Neurolife, Natal, Brazil , 5 Centro Médico de Campinas, Campinas, Brazil , 6 Endospine, São Paulo, Brazil , 7 St. Anna Hospital Herne/Marien Hospital Herne University Hospital/ Marien Hospital Witten, Germany, Herne, Germany Background: High epidural pressure during endoscopic spinal surgery can have serious consequences, particularly in cases of dural injury. To mitigate these risks, an effective outflow system is essential for maintaining appropriate pressure levels within the surgical area without compromising image quality or the efficacy of the procedure. Methods: This study compares two types of cannulas used in endoscopic spinal surgery: the conventional circular cannula and an oval cannula designed to optimize outflow. The pressure conditions in the working area were evaluated using COMSOL Multiphysics software, which simulates real-world physics with an anatomically accurate model of the human spine. Results: The oval cannula demonstrated superior performance in maintaining lower pressure within the working area, regardless of the flow rate of the saline solution. This was achieved without any adverse effect on the image quality provided by the endoscopic system. Conclusion: The use of an oval cannula in endoscopic spinal surgery is a simple and effective method for preventing dangerously high pressures within the work area. This approach ensures safer surgical conditions and may reduce the risk of complications associated with elevated epidural pressure, such as dural tears and their sequelae. Keywords: Spine surgery, endoscopic spine surgery, lumbar spine, epidural pressure, dural injury. Joshua Heller 1 , K. Brandon Strenge 2 , Alexander Lemons 3 , Pierce Nunley 4 , Rahul Shah 5 , Gabriel Tender 6 , Daniel Williams 3 , Marcus Stone 4 , Bruce McCormack 7 , Matthew Jenkins 8 , April Slee 9 , Erik Summerside 8 1 Thomas Jefferson University, Philadelphia, United States , 2 Strenge Spine Center, Paducah, United States , 3 Pinehurst Surgical Clinic, Pinehurst, United States , 4 Louisiana Spine Institute, Shreveport, United States , 5 Premier Orthopaedic Associates, Vineland, United States , 6 Louisiana State University, New Orleans, United States , 7 University of California San Francisco, San Francisco, United States , 8 Providence Medical Technology, Pleasanton, United States , 9 New Arch Consulting, Seattle, United States Introduction: Anterior discectomy and fusion (ACDF) is a common treatment for symptoms resulting from degeneration of the cervical discs. In patients with multi-level disease, a surgeon may opt to include supplemental posterior fixation to improve the chance of arthrodesis (circumferential cervical fusion, CCF), however this adjunct introduces added risk for complications, particularly when performed as an open approach with lateral mass screws and rods. This study tracked incidences of treatment-related complications through 24 months in subjects enrolled in the FUSE IDE Clinical Trial to receive treatment for symptoms from three level cervical degenerative disc disease. Incidence of complications was summarized based on randomized treatment: ACDF alone or tissue-sparing CCF. Material and Methods: Enrolled subjects presented with cervical degenerative disease at three levels and were randomized 1:1 to treatment with either ACDF alone or CCF (ACDF with tissue-sparing posterior cervical fusion). Adverse events (AEs) were summarized at 6 weeks, and 3, 6, 12, and 24 months following treatment as well as from unscheduled visits. Cox proportional hazard models were used to evaluate the relationship between treatment and hazard of first occurrence of related and non-related AEs. Relationship was adjudicated from an independent committee of three spine surgeons. A treatment related event was one that was determined to have any possible, probable, or definite relationship to the study procedures and/or devices. Results: At the time of this interim analysis, a total 57 ACDF subjects (58 ± 10 years, 54% female) and 59 CCF subjects (58 ± 9 years, 63% female) had AE data available through study conclusion. Addition of tissue-sparing PCF introduced minimal added morbidity, blood loss increased 10cc (p = 0.010), and required an additional 46.5 minutes (p < 0.001). Length of stay was 1 night and was similar between groups (p = 0.293). In the ACDF arm, 45 (78.9%) participants experienced a treatment-related AE, compared to 33 (55.9%) in the CCF arm. The reduction of risk with CCF was significant (HR = 0.53, 95%CI = 0.34 to 0.83, p = 0.005). Non-treatment related AEs occurred in 34 (59.6%) participants in the ACDF arm, compared to 41 (69.5%) in the CCF arm. The risk of a non-treatment related event did not differ by arm (HR = 1.17, 95%CI = 0.75 to 1.84, p = 0.493). Conclusion: The added surgical burden of tissue-sparing PCF did not increase risk of post-operative complications. CCF subjects experienced a reduced incidence of treatment-related AEs across 24 months when compared with ACDF alone. Giuseppe di Nuzzo 1 , Vincenzo Seneca 1 , Danilo De Paulis 1 , Roberto Granata 1 , Francesco De Falco 1 , Giuseppe Catapano 1 1 ASL Napoli 1 Centro - Ospedale del Mare, Naples, Italy Introduction: Modern surgery involves several approaches to internal fixation of the spine. In particular, using pedicle screws, different techniques can be used such as 3D fluoroscopic navigation, 2D fluoroscopy, freehand and robotic guidance. All these methods are used at our center and we therefore compared robotic positioning, fluoroscopy navigation and 2D fluoroscopy to evaluate the differences in terms of precision of screw positioning, operating time, intraoperative blood loss and overall complications. Material and Methods: From September 2020 to August 2024, over 379 patients were treated. 157 percutaneous procedures, 187 3D fluoroscopic navigation and 35 robotic procedures were performed. Over 2890 screws were placed. The methods were compared and evaluated: incorrect positioning and accuracy of the screws; operative time, overall complications, intraoperative blood loss, length of postoperative hospital stay, postoperative visual analog scale (VAS) score for back pain. Results: The robotic procedures, although significantly lower in number than the others, showed the greatest precision in optimal screw positioning, also compared to spinal navigation although not significantly so. Screws placement was faster in terms of speed in robotic and navigated procedures. The post-operative results were comparable with all methods. Conclusion: The results of our experience show the superiority of robotic technology in screw placement in accuracy and its equivalence in terms of postoperative functional results compared to other approaches. Robotic spinal surgery is proving to be increasingly valid and an excellent aid to the neurosurgeon in the treatment of spinal pathologies. Byron Delgado Ochoa 1 , Mauricio Campos 1 , Daniel Lobos 1 , Jorge Cuéllar 1 , Cristian Ruz 1 , Pablo Besa 1 , Javier Castro 1 , Catalina Vidal Olate 1 1 Pontificia Universidad Católica de Chile, Santiago, Chile Introduction: Pedicle screw placement in spinal surgery is complex and prone to errors, with significant risks to patients. Traditional training methods, like mentorship in operating rooms, pose safety concerns, prompting the need for alternative training tools. This study aimed to validate and utilize a 3D-printed simulation model for lumbar pedicle screw insertion training and assess its effectiveness compared to traditional methods. Material and Methods: The study proceeded through four phases: model design and validation, construct validation, learning curve assessment, and transfer to a cadaveric model. The results from different phases were described using either medians and interquartile range (IQR) or means and standard deviation (SD) depending on the distribution. Data distribution was assessed using the Shapiro-Wilk test. OSATS scores, Distance, Quantity of movements, and Time taken in the procedure were compared between experts and novices (first attempt) using the non-parametric Mann-Whitney test. The score of the trained group in their last session was compared to the cadaveric test score using the Wilcoxon test to calculate the transfer coefficient. The scores of the trained group in the last session was compared with the performance of the experts, and the trained group to the control group in their cadaveric tests, both using the t-test. Statistical significance was set at p < 0.05. We conducted a post hoc evaluation to power calculation with alfa 0.05 by comparing the mean difference and standard deviation between the experimental group (trained residents) and the control group (untrained residents). STATA software v.16 was utilized for analysis. Results: A 3D-printed lumbar spine model was created and refined based on expert feedback. Construct validation demonstrated the model's ability to differentiate between experts and novices. Training sessions with residents showed a significant improvement in performance over multiple attempts, but performance still lagged that of experts. However, skills learned on the simulation model effectively transferred to a cadaveric model, with no significant difference in performance observed. The trained group outperformed a control group trained using traditional methods in the cadaveric test. Conclusion: The study concludes that the 3D-printed simulation model is a valid training tool for lumbar pedicle screw insertion, effectively transferring skills to a cadaveric setting and improving resident performance compared to traditional training methods. Further research is warranted to explore the sustainability of acquired skills and optimize training protocols. Junyu Li 1 , Hanlin Xia 2 , zekun li 1 , Yilin Lu 1 , Xiang Zhang 1 , Zhuo Ran Sun 1 , Yongqiang Wang 1 , Weishi Li 1 , Duanduan Chen 2 , Miao Yu 1 1 Peking University Third Hospital of China, Beijing, China , 2 Beijing Institute of Technology, Beijing, China Introduction: Spinal deformities, including scoliosis, kyphosis, etc., are a common and potentially serious disease that can significantly affect the quality of life of patients. Surgical treatment is a key method to improve the symptoms of these diseases, and the accuracy of evaluating surgical outcomes is crucial for improving treatment success rates and a major challenge. Artificial intelligence based on deep learning methods can automatically identify the spinal canal, and then estimate various spinal parameters of the canal before and after surgery through mathematical methods to evaluate surgical outcomes. Material and Methods: Considering the metal artifacts and noise factors in postoperative CT images, the study used deep learning techniques to extract the spinal canal centerline. We have developed a 3D U-Net deep learning network that combines CBAM (Convolutional Block Attention Module) and cascaded a bidirectional recurrent neural network (Bi RNN) for spinal canal segmentation. The preoperative and postoperative spinal canal centerlines extracted by this method are used to calculate the curvature and torsion of the curve using mathematical methods, in order to evaluate the impact of surgery on spinal structure. Results: 18 patient images were included in the model training, and another 3 patients were included in the test set to evaluate the performance of the model segmentation. The Dice coefficient of the evaluation index of this model on the test set reached 0.82. Compared with the manually annotated results, the proposed deep learning algorithm can effectively extract the spinal canal centerline, even in images with metal artifacts after surgery. Calculating the changes in curvature and torsion of the spinal canal centerline before and after surgery can accurately reflect the differences in spinal morphology before and after surgery, demonstrating the effectiveness of surgical treatment for spinal deformities. Conclusion: This study provides an effective tool for clinical doctors to improve the success rate of surgery and the quality of patient rehabilitation. In addition, the results of this study also provide important reference value for other types of spinal surgeries, opening up new possibilities for future clinical research and application. Future work will further conduct biomechanical analysis of the spine based on this research, in order to provide more accurate methods for evaluating surgical outcomes. Esteban Quiceno Restrepo 1 , Isabelle Stockman 2 , Benard Okai 2 , Shashwat Shah 2 , Hendrick Francois 2 , Alexander Aguirre 1 , Asham Khan 1 , Mohamed Soliman 1 , John Pollina 1 , Jeffrey Mullin 1 1 University at Buffalo Neurosurgery, Buffalo, United States , 2 Jacobs School of Medicine and Biomedical Sciences, Buffalo, United States Introduction: Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) can be catastrophic complications associated with adult spinal deformity (ASD) surgery. These complications are significantly influenced by instrumentation configuration. Multiple adjuvant methods, including tethers and tapered rod constructs, have been developed to prevent PJK. We aimed to investigate the utility of tapered rod constructs in preventing PJK and/or PJF after ASD surgery. Materials and Methods: We conducted a retrospective chart review to identify patients aged ≥ 50 years who had received ASD surgery involving 5 or more thoracolumbar levels. Demographic, spinopelvic parameters, and procedure-related variables were collected. Univariate analysis and multivariate logistic regression were performed to determine if the use of tapered rods was a protective factor for PJK/PJF. Results: A total of 60 patients were included (mean age, 64.1 ± 6.8 years). Among them, 21 patients (35%) developed PJK/PJF, with only 5 of these patients having undergone a construct with tapered rods. On multivariate analysis, preoperative SVA was associated with PJK (odds ratio = 1.5, 95% CI = 1.48-1.83, p < .001), and the use of tapered rods was found to be a protective factor (odds ratio = 0.45, 95% CI = 0.35-0.65, p < .001). Conclusion: The use of tapered rods during spinal deformity surgery was a protective factor against PJK/PJF. A randomized controlled study is recommended to further validate these findings. Esteban Quiceno Restrepo 1 , Mohamed Soliman 1 , Asham Khan 1 , Kyungduk Rho 1 , Alexander Aguirre 1 , Jacob Greisman 1 , Benard Okai 2 , Jeffrey Mullin 1 , John Pollina 1 1 University at Buffalo Neurosurgery, Neurosurgery, Buffalo, United States , 2 Jacobs School of Medicine and Biomedical Sciences, Neurosurgery, Buffalo, United States Introduction: Accurate measurement of spinal parameters is essential for diagnosing and treating spinal disorders. Traditional manual measurement methods are time-consuming and prone to variability. This study aims to assess the accuracy and reliability of machine learning (ML) methods compared to traditional measurements performed by a neurosurgery resident (operator 1). Material and Methods: We conducted a comparative analysis of spinal parameter measurements obtained through ML models and those manually taken. Parameters examined included cervical and thoracic kyphosis, lumbar lordosis, pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), sagittal vertical axis (SVA), C7 coronal alignment (C7 CSL), thoracic Cobb angle, and lumbar Cobb angle. Data analysis utilized Pearson coefficients, p-values, and interrater reliability. Results: The results demonstrated a high correlation and significant agreement between measurements obtained through ML and Operator 1 specially in the lumbar spine. Sacral slope (SS) and pelvic tilt (PT) demonstrated Pearson coefficients of 0.84 and 0.90 (both with p-values < .001) and interrater reliabilities of 0.84 and 0.90, respectively. Sagittal vertical axis (SVA) exhibited a Pearson coefficient of 0.96 (p-value < .001) with an interrater reliability of 0.96. PI-LL and PI had Pearson coefficients of 0.59 and 0.79, respectively (both with p-values < .001) and interrater reliabilities of 0.52 and 0.79. kyphosis C2/C7 exhibited a Pearson coefficient of 0.68 (p-value < .001) with an interrater reliability of 0.66. Similarly, lordosis C2/C7 showed a Pearson coefficient of 0.58 (p-value < .001) with an interrater reliability of 0.54. Kyphosis T4-T12 demonstrated a Pearson coefficient of 0.79 (p-value < .001) with an interrater reliability of 0.76. However, C7 CSL had a lower agreement with a Pearson coefficient of 0.32 (p-value < .001) and an interrater reliability of 0.20. Thoracic and lumbar Cobb angles showed Pearson coefficients of 0.66 (p-value < .001) and interrater reliabilities of 0.55 and 0.70, respectively. Conclusion: Machine learning facilitates lumbar spinal parameter measurement accuracy and reliability, yet challenges remain in coronal parameters. Meng Nan 1 , Moxin Zhao 1 , Teng Zhang 1 , Jason Cheung 1 1 The University of Hong Kong, Department of Orthopaedics and Traumatology, Hong Kong, Hong Kong Introduction: Traditional methods for screening, diagnosing, and monitoring adolescent idiopathic scoliosis (AIS) rely on physical and radiographic examinations. However, physical exams are subjective with low reproducibility, and radiographs expose adolescents to harmful radiation. Optical techniques offer a safer alternative for frequent monitoring of spinal morphology, enabling evaluation of disease progression and treatment outcomes without radiation risks. Despite their benefits, traditional optical methods often lack clear, interpretable results. To address these limitations, we introduce EUFormer , a novel three-dimensional (3D) spinal curve generation model based on generative AI and vision transformers. Utilizing posterior and lateral optical images, EUFormer directly predicts the 3D spine morphology of AIS patients, streamlining diagnostic processes, eliminating radiation exposure, and facilitating large-scale clinical trials for screening and follow-up. Experimental results demonstrate that 3D spine morphology provides more comprehensive spatial information than 2D spine morphology, leading to more accurate disease assessments. Material and Methods: This study enrolled 3,516 consecutive AIS patients between November 2020 and June 2024. Individuals with psychological or systemic neurological conditions that could impact adherence or mobility were excluded. For each participant, posterior and lateral optical images of patient’s trunk, demographic information, and full-length spinal X-rays (EOS imaging) were collected. The spine curves obtained from biplanar X-rays were used as the ground truth (GT). Data from the training and internal validation cohort (n = 2,908) were used to develop the proposed deep learning model (i.e., EUFormer ) which generated spine curves from both posterior and lateral view. The proposed deep learning model was prospectively validated on an independent cohort (n = 608) in terms of sensitivity and negative predictive value (NPV). Results: We conducted experiments comparing the effectiveness of assessing disease severity using 3D spine morphology (i.e., 3D spine curves) versus 2D spine morphology (i.e., anteroposterior 2D spine curves). Among the 608 test samples, for the 154 normal-mild cases, the 3D spine curve predictions achieved a sensitivity of 91.5% and an NPV of 86.2%, representing a 1.6% improvement in NPV over assessments using the 2D spine curve. For the 398 moderate cases, the sensitivity was 85.7% and the NPV was 94.2%, with sensitivity improved by 5.6% and NPV improved by 5.3% compared to the 2D spine curve. For the 56 severe cases, the sensitivity was 85.7% and the NPV was 98.5%, with sensitivity improved by 5.6% and NPV improved by 1.4% over the 2D spine curve assessments. These results indicate that 3D spine morphology provides more accurate spatial information on spinal deformities than 2D spine morphology, leading to improved disease assessment. Conclusion: This study demonstrates that advanced generative AI algorithms can reconstruct 3D spine morphology directly from biplanar RGB images captured with a mobile phone for disease assessment. Experimental validation shows that assessments based on 3D spine morphology yield more accurate results than those based on 2D spine morphology. Our findings provide a more precise, radiation-free spinal examination approach, enhancing the accuracy of spine assessments using mobile phone photography. This approach facilitates precise early detection and diagnosis of AIS, leading to more prompt and effective treatment plans. Ramon Guerra Barbosa 1 , Newton Pimenta 2 , Gustavo Lages 3 1 Hôpital de Chicoutimi, Neurosurgery, Spine Surgery, Saguenay, Canada , 2 CHUS Sherbrooke, Neurosurgery, Sherbrooke, Canada , 3 Clinica Medular, Neurosurgery, Montes Claros, Brazil Introduction: Recurrent lumbar disc herniation (rLDH) presents a clinical challenge, often necessitating reoperation. Traditional open surgery poses risks such as dural tears and increased recovery time. Endoscopic techniques have emerged as minimally invasive alternatives, offering potential advantages in reducing complications and improving recovery times. This study systematically reviews the outcomes of endoscopic approaches for rLDH, supported by illustrative case reports. Material and Methods: A comprehensive search was conducted in PubMed using the keywords “recurrent disc herniation” AND “endoscopy” for studies published between 2004 and 2024. A total of 296 articles were initially identified, with 19 selected based on relevance to the surgical treatment of recurrent disc herniation. Outcomes related to pain relief, re-recurrence, and complications were analyzed. Additionally, we present two illustrative cases treated at our institution, highlighting the practical application of endoscopic reoperation techniques. Results: Endoscopic surgery demonstrated shorter surgical times compared to open surgery, with differences of up to 52 minutes. Additionally, blood loss was significantly reduced in the endoscopic group, with average reductions ranging from 53 to 151 mL. Both approaches showed similar recurrence rates, approximately 5.7%, with no significant differences. The complication rate was lower in the endoscopic group, with fewer dural tears and infections. In terms of pain relief and functional improvement, both techniques yielded comparable outcomes, with no significant differences in long-term follow-up. Endoscopic surgery also resulted in shorter hospital stays, with most patients being discharged within 24 hours. Conclusion: Endoscopic reoperation for rLDH is a safe and effective alternative to traditional open surgery, with comparable recurrence rates and a lower incidence of complications. The minimally invasive nature of endoscopy allows for faster recovery and lower morbidity, making it an ideal option for patients with recurrent disc herniation. Ramon Guerra Barbosa 1 , Newton Pimenta 2 , Gustavo Lages 3 1 Hôpital de Chicoutimi, Neurosurgery, Saguenay, Canada, 2 CHUS Sherbrooke, Neurosurgery, Sherbrooke, Canada, 3 Clinica Medular, Neurosurgery, Montes Claros, Brazil Introduction: To describe the use of spinal endoscopy for the implantation of paddle electrodes in spinal cord stimulation (SCS), highlighting its advantages, technical aspects, and challenges when compared to conventional techniques. Material and Methods: A comprehensive literature review was conducted using PubMed, focusing on articles published between 2014 and 2024. The search was restricted to English-language publications related to endoscopic techniques for SCS paddle electrode implantation. Of the 26 identified articles, only 4 directly discussed this topic. These included one article on biportal endoscopy, a cadaveric feasibility study, and two clinical reports authored by the authors detailing the monoportal endoscopic implantation technique. The technical feasibility, clinical outcomes, and limitations of the techniques were analyzed. Results: The monoportal interlaminar approach for paddle electrode implantation, as described by the authors, involves a small 10-mm parasagittal incision, insertion of a working cannula, and visualization of the lamina and ligamentum flavum under direct endoscopic guidance. A high-speed drill is used to perform a partial laminectomy, allowing for the safe passage of the paddle electrode. Under fluoroscopic guidance, the electrode is advanced to the target location without compressing the dural sac. This technique offers advantages such as minimal bleeding, reduced postoperative pain, and a lower risk of infection. However, it requires specialized equipment and comes with a steeper learning curve compared to traditional methods. The biportal technique and cadaveric studies also demonstrated feasibility, but they similarly highlighted increased cost and technical complexity as significant challenges. Conclusion: Endoscopic spinal cord stimulator paddle electrode implantation is a minimally invasive alternative to traditional open surgeries, with promising results in terms of safety, reduced complications, and improved patient recovery. Nevertheless, the higher cost associated with endoscopic equipment and the extended learning curve limit its broader adoption. Further clinical trials are needed to validate the long-term benefits and address these barriers. Jonas Krueckel 1 , David Schiffelholz 1 , Melanie Schindler 1 , Volker Alt 1 , Siegmund Lang 1 1 University Hospital Regensburg, Department of Trauma Surgery, Regensburg, Germany Introduction: The complexity of spinal cord injuries (SCI) and the diversity of potential therapeutic approaches require a deep understanding of pathophysiology, as well as precise diagnosis and individually tailored treatment strategies. Patients often face the challenge of comprehending complex information and the potential impacts of various treatment options. In today's digital era, new opportunities arise to support patients and their families with accurate and easily accessible online information. Incorporating Artificial Intelligence (AI), especially Large Language Models (LLMs) like ChatGPT, into patient education could enhance the understandability and personalization of the information provided and facilitate communication between doctors and patients. However, the reliability and appropriate use of these technologies in SCI education warrant careful examination. The effectiveness of LLMs in patient education appears promising, prompting this study to explore and evaluate their role and efficacy in medical practice. Material and Methods: A Google search for “frequently asked questions and spinal cord injury” was conducted to examine the first 20 hits according to specific inclusion and exclusion criteria to identify relevant questions. This was complemented by a targeted search in PubMed and a direct inquiry to ChatGPT-4 to determine the most common patient questions about SCI. This three-step method resulted in a pool of 120 questions, from which the 10 most frequently asked questions were selected and focused on the most critical topics. These questions were then presented to ChatGPT 3.5, ChatGPT 4 and Google Gemini, with their responses recorded and assessed for clarity, accuracy, and completeness using an established rating system. Ratings were made on a 4-point scale from “unsatisfactory” to “excellent,” supplemented by a 5-point Likert scale to assess the clarity and professionalism of the responses. Results: The preliminary evaluation of the combined question set indicates that all responses were adequately clear, with none requiring substantial clarification. A minor proportion, 10%, necessitated moderate clarification, while 33.3% warranted minimal clarification. A majority, 56.6%, were categorized as excellent, reflecting a high standard of response quality. Upon examining the overall rating distribution, there was negligible variance between Google Gemini and ChatGPT 3.5, indicating a comparable level of performance between the two. In contrast, ChatGPT 4 exhibited a statistically significant enhancement in its overall rating distribution, suggesting a refined performance over its predecessors. Furthermore, Gemini received slightly higher ratings for its empathy and professionalism, while ChatGPT 4 offered more comprehensive and professional responses. Conclusion: This observation underscores the importance of further improvements in integrating nuanced, human-like qualities into response mechanisms for professional engagement. Additionally, Large Language Models (LLMs) have proven their ability to provide precise, user-friendly information on spinal cord injuries, highlighting their significance in patient education. These insights stress the ongoing need for research to improve LLMs for medical communication, striving to combine their technical accuracy with the crucial qualities of empathy and professionalism in healthcare discussions. Karel Willems 1 1 AZ Delta Roeselare, Orthopaedic Surgery, Roeselare, Belgium Introduction: Anterior cervical discectomy and fusion (ACDF) is frequently used to treat cervical degenerative diseases and fractures. Titanium and PEEK are two of the most popular materials for fusion cages. PEEK is an excellent material but leads to limited osseointegration. Titanium cages potentially create more subsidence and on CT scans create more scattering images, blurring the evaluation of formation and ingrowth of bone. A 3D printing technology has opened new possibility to design and manufacture the titanium cage with unique topography, especially the endplate contact surface. This dynamic contact surface of this creates optimal biomechanical conditions for bone settlement and ingrow process. 3D printing technology allows significant reduction of metal volume which gives the possibility to evaluate the ingrowth process at bone-cage interface and potentially analyze bone scaffolds inside the titanium cage. Materials and Methods: We analyzed the clinical and radiological results of 50 patients 3 months after surgery. We included patients between 35 and 65 years, who underwent one- or two-level fusion. To assess this, we employed the Visual Analog Scale (VAS)score, Neck Disability Index Questionnaire, and performed a CT scan three months after surgery to evaluate bone formation at the endplates and the bone scaffold in the cage. We compare smokers versus non-smokers. Discussion To avoid subsidence, mechanical and physical properties of cage have been designed to reach as close as possible bone properties. By using titanium exclusively as a mesh-like endplate surface. Multipoint contact distributes loads evenly and eliminates stress shielding affect which is major factor in subsiding process. Additionally, incorporating of 3D printing topography and ensuring immediate stability while preserving the same elasticity as bone. Thanks to its hollow core, this design results in significantly reduced scattering on CT scans, enabling us to observe bone formation much more effectively. Since smoking status did not negatively impact outcomes, ACDF using 3D printed Titanium cage may be a reasonable option for selected patients who have smoked. Conclusions: The novel 3D-printed titanium cage is a secure implant that minimizes subsidence, fosters bone formation, and leads to reduced CT scan artifacts. Vivek Shankar 1 , Shashi Sah 2 , Rajesh Kumar 1 , Akash Vishwakarma 1 1 All India Institute of Medical Sciences, Department of Orthopaedics, New Delhi, India , 2 Primus Super Speciality Hospital, Department of Orthopaedics, New Delhi, India Introduction: Ossification of ligament flavum (OLF) is a pathological heterotopic ossification in lower thoracic level due to strong traction force with kyphotic alignment. We report two cases of lower thoracic OLF with spastic paraparesis treated with laminectomy with high frequency burr. Material and Methods: Case 1: A 51 years old male with pain in dorso-lumbar spinal for 4 years, tingling and numbness, slipping of shoes, hypoesthesia at T9-12 with increased tone bilateral lower limb, exaggerated superficial and deep tendon reflexes, plantar extensor response and ankle clonus, with normal bowel bladder. CT scan revealed ossified ligamentum flavum in T9-10, T10-11 and T11-12 with remarkable stenosis. MRI showed low intensity lesion with intra-canal occupation at the T11-12 level. Spinal decompression at T9-10, T10-11 and T11-12 were done by bilateral laminectomy with the help of high frequency burr. r. The dura was fully decompressed with free mobility without any remnant of ossification. Case 2: A 37 years old male with pain in dorso-lumbar region with radiation to right lower limb, tingling, numbness, and weakness, imbalance while walking and slipping of shoes. MRI imaging showed OLF with spinal canal stenosis. Spinal decompression was done at T10-11 via bilateral laminectomy using high frequency burr. Results: For osteotomy in spine surgeries, high-speed burrs are widely used, however, the heat generated by the tip of the device may lead to the damage to the neighboring neural tissues and may also lead to osteonecrosis. We used high-speed burr for the decompression with constant irrigation with normal saline to prevent the dural injury. Conclusion: We presented 2 cases of lower thoracic OLF in Indian men. These cases indicate that symptomatic OLF might present in Indian population despite of absence of risk factors. These can be treated with surgical decompression with high-speed burrs with constant irrigation with normal saline. Use of high speed burr with constant irrigation is effective in saving dura during decompression and can be used as a novel technique. Charles Taylor 1 , Chuck Lam 2 , Nikhil Manoj 1 , Omkaar Divekar 1 1 St George's Hospital, Department of Orthopaedics, London, United Kingdom, 2 University of Birmingham, School of Medicine and Dentistry, Birmingham, United Kingdom Introduction: Spinal fusion is a common form of spinal surgery that permanently connects two or more vertebrae to restrict movement, correct deformity or reduce pain, the most common of which involves pedicle screw placement (PSP). Despite their well-documented benefits, pedicle screws are still associated with several intra-and post-operative complications. This area of surgery has subsequently been recipient to many innovative technical and surgical developments in recent years. Currently, at the forefront of surgical interest is Augmented Reality Surgical Navigation (ARSN). This systematic review aims to evaluate whether when compared to the current standard of care, ARSN-enhanced surgery results in superior screw accuracy and operative outcomes for patients undergoing PSP surgery. Material and Methods: Data collection was performed on PubMed, Ovid MEDLINE, the Cochrane Library, Embase and the Web of Science between 01/07/2023 and 01/08/2024. PRISMA guidelines were followed and the level of evidence was graded per the Centre for Evidence-Based Medicine’s recommendations. Risk of bias was assessed per the ROBINS-I tool and the Cochrane guide for assessing study quality. A modified version of the Newcastle/Ottawa Scale was used to determine the certainty of the body of evidence. Data extraction and statistical analysis was performed on SPSS (version 26.0.0.0) and Stata (version 105 17.0.0.0). Data was collected on: Accuracy of screw placement (Gertzbein-Robertson grading), time to place a screw (seconds), duration of surgery (minutes), Intraoperative blood loss (mL) and Length of hospital stay (days). Outcome analysis was performed by way of a one-way ANOVA and unpaired two-sample z-test. Secondary outcome measures were analyzed via independent samples t-test. Results: Following the literature search, 521 papers were obtained from all bibliographical and non-bibliographical databases. Following full-text screening, 31 papers were included in the final review. This review finds that ARSN results in significantly greater PSP accuracy, (p < 0.000), significantly reduced intraoperative blood loss (p = 0.050), comparable operative duration (p = 0.819), comparable time required to place a screw (p = 0.703) and a non-significant reduction in hospital stay (p = 0.097). Conclusion: Based on 19 high to moderate quality studies that placed a total of 2,157 pedicle screws with ARSN between the first cervical vertebrae and the iliac spine of patients, cadavers and vertebral models, it can be concluded that ARSN results in a significantly greater number of screws placed at Gertzbein-Robertson grade 1 or grade 2 when compared to non-ARSN surgery. ARSN could therefore be considered as a safe and efficacious technical innovation within pedicle screw placement surgery. Chen Jin 1 , Hao-Jie Chen 1 , Rui-Jun Xu 1 , Xiao-Jian Ye 1 , Jiang-Ming Yu 1 1 Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China Introduction: Percutaneous vertebroplasty (PVP) is an effective and commonly surgical treatment for osteoporotic vertebral compression fractures, but the problem of bone cement leakage still cannot be prevented. It has been reported that the incidence of cement leakage occurs in up to 20% of vertebroplasty procedures, which the most serious complications are spinal cord compression and pulmonary embolism. In this study, with the aid of the novel bone cement injection device, precise control of bone cement injection dosage and injection pressure restriction can be achieved successfully, as well as the decreased risk of bone cement leakage. Material and Methods: Two fresh-frozen human cadaveric thoracic and lumbar spines (T1-L5) were used in the test. All cadaveric specimens had no obvious lumbar vertebra deformity, trauma defects induced by spine fracture under fluoroscopy and no previous spine surgery. An initial CT scan was performed and reviewed for needle trajectory planning. The cement was injected inside the lumbar and thoracic vertebrae of cadavers for testings in conditions similar to usual practice, with the guidance of a fluoroscopy device. In each of these experiments, bone cement was prepared using conventional manual procedure and injected by one experienced orthopaedic surgeon. The control group received PVP by the surgeon. The experimental group received PVP by the bone cement injection device. The amount of bone cement injected into thoracic vertebral body was 4.0 ml, and lumbar vertebral body was 5.0 ml. The time of surgery and the number of fluoroscopic were recorded. The diffusion and leakage of bone cement in vertebra were observed by the third party who had not participated in the surgeries. Statistically significant differences were demonstrated with P values less than 0.05. Results: There were no significant differences in the number of intraoperative X-ray fluoroscopies between the experimental group and the control group. Operation time was significantly longer in control group (164.3 ± 18.7 s) than that of experimental group (72.0 ± 7.2 s). Leakage of cement outside of the vertebral body was noted in 4 of 10 injected vertebrae in control group. There was no bone cement leakage in experimental group. Conclusion: This study presented the design and evaluation of a system dedicated to bone cement injection. The safety and feasibility of the novel bone cement injection device is high, and it has the value of popularization and application. Limin Zou 1 , David Yuen-Chung Chan 1 , Yitian Xian 1 , Man Cheong Lei 1 , Danny Tat Ming Chan 1 , Zheng Li 1 1 The Chinese University of Hong Kong, Surgery Department, Hong Kong, China Introduction: In Artificial Disc Replacement (ADR) surgeries, the grinding heat induced by high-speed drill (temperatures > 50°C) can damage bone and adjacent tissues, increasing risks of implants subsidence, spine instability and neural compression. Hence, precise temperature control is crucial to ensure surgical safety. Most of the existing temperature prediction models for bone processing are mathematical regression and computational engineering models. The facing challenges includes material properties assumptions, data dependency, and limited generalizability. Thus, employing advanced techniques is demanded to enhance accuracy and adaptability. Random forest regression (RF) provides excellent prediction accuracy by managing the complex variables interactions and contribute to modeling complex phenomena. Therefore, this study proposed a data-driven RF temperature prediction model, leveraging a substantial dataset from in-vitro grinding experiments. Methods and Materials: This study monitored the temperature changes during grinding using a neurosurgical high-speed drill (Stryker PI-DRIVE MOTOR, maximum speed 75,000 rpm), with a 4-mm diamond burr. The tests were conducted on a 3-axis linear platform. Influences of key variables in grinding such as rotational speed, cutting depth, grinding time, contact area and feed rate are studied. An HIMICRO K20 infrared imager with measurement range of -20∼400◦C (accuracy of 2%) was 30 cm above the bone to capture real-time temperature changes. For the in-vitro tests, all parameters were grouped using an orthogonal experimental method to encompass all possible combinations of factors. RF models were employed to predict temperature changes, with further comprehensive performance analysis. The proposed RF model was trained on normalized data, with out-of-bag (OOB) error monitored. De-normalized predictions were evaluated using Root Mean Square Error (RMSE), Coefficient of Determination (R 2 ), Mean Absolute Error (MAE), Mean Bias Error (MBE), and accuracy, including predictions within a 10% error margin. Feature importance was also analyzed. Results: This study simulates layer-by-layer bone grinding and investigates the maximum temperature rise during dry grinding. A total of 171 tests were conducted, with 1215 sets of temperature and grinding parameter data. Speeds ranged from 50000 to 70000 rpm (5000 rpm intervals), and feed speeds were 7.5 to 15.0 mm/s. Force values at different depths were: 0.261-8.233N (mean: 2.60N) for 0.05 mm; 0.037-28.344N (mean: 4.04N) for 0.1 mm; and 0.037-24.543N (mean: 4.75N) for 0.2 mm. The Random Forest model performed well on both datasets. The training set had an RMSE of 1.5859, accuracy of 96.44% (within ± 10% error), and R 2 of 0.97607. The MAE was 1.1361, with a slight positive MBE of 0.07259. The test set had an RMSE of 1.7094, accuracy of 94.31%, and R 2 of 0.97582. The MAE was 1.1906, and the MBE was -0.03027, showing minimal bias. These results demonstrate strong generalization and predictive accuracy on unseen data. Conclusion: In this study, a RF model was developed to predict temperature changes during cervical ADR grinding. The model achieved high accuracy, with an R 2 value of 0.97582 and 94.31% accuracy on the test set. It effectively captured the relationship between grinding parameters and temperature, showing its potential for grinding temperature prediction. Future work could focus on improving the prediction accuracy and temperature reduction. Vadim Byvaltsev 1,2,3 , Andrei Kalinin 1,3 , Marat Aliyev 4 , Yurii Pestryakov 1 , K. Daniel Riew 5 6 1 Irkutsk State Medical University, Neurosurgery, Irkutsk, Russian Federation , 2 Irkutsk State Medical Academy of Postgraduate Education, Traumatology, Orthopedic and Neurosurgery, Irkutsk, Russian Federation , 3 Railway Clinical Hospital, Neurosurgery, Irkutsk, Russian Federation , 4 Asfendiyarov Kazakh National Medical University, Neurosurgery, Almaty, Kazakhstan , 5 Columbia University, Orthopedic Surgery, New York, United States , 6 Weill Cornell Medical Schoo, Neurological Surgery, New York, United States Introduction: Currently, there are no structured algorithms justifying the personalized use of various neurosurgical technologies taking into account individual morphological changes in the lumbar segments of professional athletes. Purpose of this study was to analyze of the results of surgical treatment of athletes with lumbar degenerative disease and development of a treatment algorithm. Material and Methods: For 114 athletes with lumbar degenerative disease were included in the present study. Four independent groups were studied: (1) microsurgical/endoscopic discectomy (n = 35); (2) PRP therapy in facet joints (FJ) (n = 41); (3) total disc replacement (TDR) (n = 11); (4) lumbar interbody fusion (LIF) (n = 27). Evaluated postoperative clinical outcomes and preoperative radiological results. The average postoperative follow-up was 5 (3;6), 3.5 (3;5), 3 (2;4) and 4 (3;5) years, respectively. The analysis included an assessment of clinical outcomes (initial clinical symptoms, chronic pain syndrome level according to the VAS, quality of life according to the SF-36 questionnaire, degree of tolerance to physical activity according to the subjective Borg Rating of Perceived Exertion Scale) and radiological data (Dynamic Slip, Dynamic Segmental Angle, degenerative changes in the facet joint according to the Fujiwara A. classification and disc according to the Pfirrmann C. classification; changes of the Apparent diffusion coefficient (ADC) using diffusion-weighted MRI). Results: The average timing of return to sports were 12.6 (10.2;14.1), 2.8 (2.4;3.7), 9 (6;12), and 14 (9;17) weeks, respectively. We examined the type of surgical treatment utilized, as well as the preoperative clinical symptoms, severity of degenerative changes in the intervertebral disc and FJ, the timing of return to sports, the level of pain syndrome, the quality of life according to SF-36, and the degree of tolerance to physical activity. We then developed an algorithm to optimize neurosurgical treatment based on individual preoperative neurological function and lumbar morphological changes. Conclusion: In conclusions, we reviewed the clinical outcomes of our athlete patients treated with 4 different surgical modalities: Micro/endo discectomy, PRP, TDR and LIF. We then utilized the data to develop an algorithmic approach to these patients. For those in our Minimal (discogenic) group, with a herniated disc, preserved disc height, radicular over lumbago symptoms with mild disc degeneration, and all other radiological parameters normal, Micro/Endo Discectomy is recommended. For those in our Minimal (arthrogenic) group, who were identical to the first group except that they had mild FJ degeneration, a disc protrusion instead of herniation and predominantly had lumbago instead of radicular symptoms, PRP treatment is recommended. For those in our Moderate (discogenic) group, with a herniated disc, preserved disc height, moderate disc degeneration, decreased ADC, mild FJ degeneration, no Dynamic Slip, minimal Dynamic Sagittal Angle and predominantly radicular symptoms over lumbago TDR is recommended. Finally, for our Severe (disco-arthrogenic) group, who had a disc herniation with any of the following: disc height < 1/3 of suprajacent disc, advanced disc degeneration, ADC 4 mm or Dynamic Sagittal Angle > 20 0 with mixed radicular and lumbago symptoms, we recommend instrumented arthrodesis. Tiago Andrade de Oliveira e Silva 1,2 , Hiram Fernandes Soares 3 , Kelvin Luan Bueno 4 , Nikson Leonard Ferraz 4 , Anne Ribeiro Sampaio 3 , Valdecir Boeno Spenazato Júnior 3 , Raquel Descie Veraldi Leite 4 1 Santa Casa de Misericórdia de Barretos, Barretos, Brazil, 2 Universidade de São Paulo, Bioengineering, São Carlos, Brazil, 3 Hospital de Amor, Barretos, Brazil, 4 Harena Inovação, Barretos, Brazil Introduction: The integration of augmented reality (AR) into spine surgery has the potential to revolutionize intraoperative visualization and precision. VHolom, a company specializing in AR technology, has developed an advanced platform compatible with the Meta Quest headset, allowing real-time holographic representations of anatomical structures during surgery. In this study, we present the case of a 14-year-old female diagnosed with idiopathic scoliosis, exhibiting a 73° COBB angle with conservative treatment failure, respiratory restriction and lower limbs hyperreflexia. Scoliosis surgery, which demands precise planning and execution to correct spinal deformities, traditionally relies on intraoperative radiographs and navigation systems. The objective of this study was to assess the use of AR through the Meta Quest system in assisting surgical planning, particularly with regard to incision estimation and guidance during instrumentation. Materials and Methods: The patient was positioned under general anesthesia, and neuromonitorization was applied throughout the surgery to prevent neurological deficits during corrective maneuvers. The Meta Quest headset, equipped with the VHolom AR platform, was used to visualize a holographic overlay of the patient's spine, generated from preoperative imaging. The holography provided real-time feedback on the spinal anatomy, intended to assist in the estimation of the required incision length and optimal positioning of pedicle screws. The AR guidance was compared with standard intraoperative X-ray navigation. A shift in the AR overlay, simulating the original curvature of the spine, was detected prior to instrumentation. This resulted in the discontinuation of AR guidance in favor of traditional methods to ensure surgical accuracy and safety. Results: The use of the AR system provided significant benefits during the initial phases of surgery, especially in the preoperative planning and estimation of incision length. The visualization was comparable to that obtained through X-ray guidance, providing a clear outline of the deformed spine and facilitating better preparation for the surgical approach. However, a technical complication arose when the AR simulation failed to accurately adjust to intraoperative changes, causing a shift that reflected the original curvature of the scoliosis. This led to concerns about the potential for errors in instrumentation placement. As a result, the AR guidance was aborted, and the surgery continued using traditional radiographic techniques. Despite this limitation, the patient experienced no neurological deficits, and the procedure was completed successfully. Conclusion: Augmented reality holds promise as a tool for enhancing surgical precision in scoliosis correction, offering advantages in terms of preoperative planning and intraoperative visualization. However, the limitations encountered in this case, particularly the shift in the AR overlay during instrumentation, underscore the need for further refinement of the technology before it can fully replace traditional guidance systems. The use of neuromonitorization was crucial in preventing neurological complications, and X-ray guidance remains the gold standard for ensuring accuracy during instrumentation. While AR technology shows potential, it is not yet ready to be relied upon as the sole method for guidance during scoliosis surgery. Further studies and technical improvements are necessary to address these challenges. Federico Iaccarino 1 , Demo Eugenio Dugoni 2 , Giacomo Pavesi 1 , Alessandro Landi 2 , Pietro Vittorio La Cava 2 , Corrado Iaccarino 1 1 UNIMORE, Modena, Italy , 2 Centro Chirurgico Toscano, Arezzo, Italy Introduction: Robotic spine surgery is an increasingly widespread reality in the world, in Europe and in Italy. The technology available today should make it possible to overcome some important limitations of free-hand or “traditional” spinal surgery. There is now numerous international literature that supports this belief or hope. The aim of our study is to analyze the robotic surgery activity carried out by comparing it with “free-hand” surgery. Material and Methods: In this single-center retrospective study, 130 cases of spinal surgery performed with Medtronic MAZOR robotic technique from 01/01/2021 until 01/08/2024 at Centro Chirurgico Toscano were collected and compared with 130 cases performed with the “free-hand” technique in the same period. We tried to make the two groups as homogeneous as possible and the surgeons are the same for both groups. The parameters detected are: sex, age, pathology, type of intervention, technique (open or percutaneous), entry-start surgery time, type of robotic technique (scan and plan or TC to fluoro), number of screws, number of cages, duration of the operations, duration of implantation of the screws, accuracy of the screws (Gertzbein-Robbins classification), exposure to radiations, revisions, infections, hospitalization times, blood transfusions. Clinical outcomes were measured by the Oswestry Disability Index (ODI). Results: Robotic spine surgery has important advantages compared to “free-hand” surgery in terms of accuracy of pedicle screws positioning. It significantly reduces implantation times, a difference that increases exponentially in the case of long constructs. It reduces exposure to radiations for both surgeons and patients and in our experience, in terms of the overall duration of the intervention, infections, hospitalization times and blood transfusions we have not found any important difference. From a clinical point of view, a 10% difference in means was observed to the most recent checks between ODI of the patients operated with robotic (5%) and free-hand (15%) surgery. Conclusion: Robotic spine surgery has important advantages compared to “free-hand” surgery, particularly in cases of complex pathology or anatomy. The preparatory stages can be long and must be carried out with the greatest possible care. The learning curve not only of the surgeon, but of all the operating room staff, is long and represents a crucial point in the speed of execution of the operation. Federico Iaccarino 1 , Demo Eugenio Dugoni 2 , Giacomo Pavesi 1 , Alessandro Landi 2 , Pietro Vittorio La Cava 2 , Corrado Iaccarino 1 1 UNIMORE, Modena, Italy , 2 Centro Chirurgico Toscano, Modena, Italy Introduction: Degenerative adult kyphoscoliosis is an extremely complex pathology. Alongside antero-lateral approaches to the spine, new tools have emerged that can be used for the treatment and correction of deformities: robotic spinal surgery and AI platforms. The latter allow optimal pre-operative planning, with a valid contribution to its meticulous realization. Some platforms even allow the creation of pre-shaped bars based on planning, allowing the most operator-dependent variable to be eliminated from the equation. Material and Methods: Three cases have been carried out with pre-operative planning using AI since November 2023 at Centro Chirurgico Toscano in Arezzo. After uploading the pre-operative neuroradiological exams online, the AI platforms propose various solutions that allow correct sagittal and coronal balancing, which the surgeon will examine and choose based on experience and preferences. Furthermore, using AI through machine-learning mechanisms, it will be able to propose solutions increasingly in accordance with the therapeutic lines of the various surgeons. Another complementary tool at our disposal was the precision of the robotic technique in positioning the posterior screws, which allowed total adherence to the pre-operative planning. Results: In all cases, post-operative and remote checks showed the correct positioning of the fixation devices, a return of the spino-pelvic indices to normal ranges and the neurological objective examinations remained negative. Conclusion: The use of AI for pre-operative planning and the creation of pre-shaped bars, integrated with the use of robotic surgery for the positioning of the screws, allow the achievement of the desired degrees of lordosis at each level, optimal seating of the bars, with reduction of stress on the implant, a correction of the deformity similar to the ideal planned one, greater stability of the construct over time, with reduction of the risk of loss of correction and junctional pathology. Matheus Augusto Ferreira Rocha 1 , Lucas Queiroz Mendes 1 , Anderson Dias 1 , Rafael Gonçalves Da Cruz 1 , Claudio Kenji Arakaki Carvalho 1 , Leonardo Franco Pinheiro Gaia 1 , Bernardo Sousa Fernandes 1 , Marlus Salomão 1 , Andrea Gasparina 1 , Dernival Bertoncello 1 1 Federal University of Triângulo Mineiro, Uberaba, Brazil Introduction: 3D printing has been widely applied in medicine, with a significant impact on several areas, including spinal deformity surgery. Customization of anatomical models offers greater precision in surgical planning and potentially reduces the risk of intraoperative complications. This study aims to systematically review the literature on the use of 3D printed models in the surgical treatment of spinal deformities such as scoliosis, kyphosis and other conditions. Material and Methods: Inclusion Criteria: Clinical trials, observational studies, retrospective studies and narrative or systematic reviews. Patients with spinal deformities such as scoliosis and kyphosis. Use of 3D printed models for surgical planning. Surgical precision, operative time, complications, cost-benefit, patient and surgeon satisfaction. Articles not directly related to the use of 3D printing for spinal deformity, studies with incomplete or irrelevant outcomes, and isolated case reports without comparison were excluded. The searches were carried out in the databases: PubMed, Embase, Scopus, and Cochrane Library, using the following keywords:”3D printing” AND “spine deformity” AND “surgery”, “3D printed models” AND “spinal surgery” AND “scoliosis”, “Patient-specific models” AND “spine deformity” AND “3D technology” from 2016 to 2023 in English and Portuguese. Two independent reviewers analyzed the titles and abstracts of the identified articles. Those that met the inclusion criteria proceeded to full review. Discrepancies were assessed by a third reviewer. Results: After the initial screening, 107 articles were identified, of which 5 met the inclusion criteria and were fully reviewed. Regarding surgical precision Zhang et al. (2020) evaluated the placement of pedicle screws guided by 3D models in 50 patients with scoliosis. The accuracy rate was 95%, compared to 85% in cases where surgery was performed without a printed model. Chen et al. (2019) reported a significant improvement in surgical precision and spinal alignment in patients with kyphosis when 3D anatomical models were used for surgical planning. Wang et al. (2018) investigated the impact of 3D models on operative time and reported an average reduction of 20% in surgery time for scoliosis correction compared to the traditional method. Li et al. (2021) carried out a retrospective analysis of 200 patients and observed a reduction in surgical complications when planning was carried out with 3D models. The complication rate decreased from 12% to 5%. A cost analysis performed by Smith et al. (2017) indicated that although the use of 3D printing involves additional costs in the planning phase, there were significant savings in surgery time and reduced complications, which offset the initial costs. Conclusion: 3D printed models have a promising role in the surgical treatment of spinal deformities, with clear benefits in terms of accuracy, operating time and reduction of complications. Although more studies are needed to confirm large-scale applicability and financial impact in different contexts, existing data is encouraging. Amir Sharif 1,2 , Hamid Reza Abbasi 2 1 Regio Klinikum Pinneberg, Spine Surgery, Pinneberg, Germany , 2 Inspired Spine, Spine Surgery, Burnsville, United States Introduction: The rapid advancement of computer technology in medicine has presented both challenges and opportunities. While the increase in medical data and its legal documentation requirements have escalated healthcare costs due to the additional administrative workforce, the need for more efficient data management systems has become evident. This study explores the development and implementation of an internally produced artificial intelligence (AI)-based medical scribe system aimed at reducing the reliance on human labor for medical documentation in a private independent medical practice. Material and Methods: Our practice implemented an AI system, termed Suri (smart universal resource identifier), using the openly available OpenAI model. The system was designed by two in-house programmers to accurately transcribe doctor-patient interactions and compile comprehensive medical records in multiple languages. We transitioned from employing eight human scribes, incurring an annual cost of $340,000, to utilizing our AI system for scribing needs, disease coding, procedure documentation, and billing processes. Results: The AI scribe not only provided transcriptions more accurate than traditional dictation software like Dragon but also demonstrated the ability to understand accented English and generate correctly ordered medical records without requiring input to be structured. Additionally, Suri facilitated data analysis, medical transcription, and report drafting -capabilities showcased by this very abstract being composed by the system itself. Conclusion: The implementation of an internal AI scribe system proved to be a viable solution for reducing administrative burden and cost in a private medical practice. With Suri's self-learning capabilities, our project's next phase aims to develop a fully AI-based medical record system to encompass documentation, reports, coding, billing, and scheduling. This endeavor is expected to significantly decrease reliance on human labor and revolutionize the standard practices in medical record-keeping within the next two years. Majdi Ben Romdhane 1 , Ben Theyer Maher 1 , Majdi Sghaier 1 , Bedoui Mootez 1 , Charfi Mahdi 1 , Rafik Elafrem 1 1 Internal Security Forces Hospital, Ariana, Tunisia Introduction: Posterior cervical spine osteosynthesis is increasingly popular for providing stable arthrodesis along with decompression and release. Currently, pedicle screw placement is the standard practice for achieving spine stability. However, the complexity of this anatomical region and the presence of vital structures pose significant challenges. Cervical pedicles are anatomically smaller compared to thoracolumbar pedicles, making the surgical procedure more delicate and prolonged with a notable risk of postoperative complications. To address this issue, we have adopted a novel approach: 3D reconstruction and 3D-printed guides. Materials and Methods: This preliminary retrospective study involved two cases of cervical spondylosis from C3 to C7, with signs of myelopathy on imaging. The surgical indication was posterior spinal fusion with pedicle screws and decompression. Surgical planning began with cervical spine CT imaging followed by 3D reconstruction to understand the patient's anatomy and pre-plan screw trajectories. Custom 3D-printed guides were then created for each vertebra based on the pre-established screw paths. Evaluation metrics included operative time, bleeding, postoperative complications (particularly neurological), and screw positioning accuracy compared to preoperative planning using radiological control (CT). Results: The average operative time was 160 minutes. Image intensifier use was required only twice. No blood transfusions were necessary postoperatively. Postoperative outcomes were uncomplicated: no neurological issues, resolution of paresthesias, and a significant reduction in cervical radiculopathy. Postoperative CT scans demonstrated screw placement accuracy of 90% (with screws deviating by 4° transversely and 5° frontally). The average postoperative hospital stay was 4 days. Discussion: Pedicle screw placement in the cervical spine is challenging due to anatomical complexity and the small size of the pedicles. Precise screw positioning is crucial for achieving solid arthrodesis and avoiding complications. This technique has demonstrated the feasibility of achieving intra-pedicular screw placements that closely match preoperative plans, thereby mitigating potential complications such as neurological damage to the spinal cord and roots or vascular injury to the vertebral artery. The procedure duration was reduced with lower risk of infection and minimal reliance on image intensification. Conclusion: The combination of 3D reconstruction and intraoperative augmented reality navigation has yielded excellent results with precise anatomical accuracy, minimizing complications. This approach facilitates the surgical procedure, making it more reproducible and manageable. Majdi Ben Romdhane 1 , Ben theyer Maher 1 , Bedoui Mootez 1 , Majdi Sghaier 1 , Rafik Elafrem 1 1 Internal Security Forces Hospital, Ariana, Tunisia Introduction: The cervical region's anatomy is intricate due to the proximity of vital organs to the osteo-ligamentous structures of the cervical spine. This complexity renders any surgical approach delicate, with significant risks of vascular and neurological complications. Preoperative planning and a comprehensive understanding of the patient's specific anatomy are crucial for ensuring successful surgical outcomes. We have adopted a new technique: pedicle screw navigation using augmented reality. Materials and Methods: The patient, diagnosed with cervicarthrosis at levels C3-C7 accompanied by cervical myelopathy and neurological signs, was indicated for a posterior arthrodesis with pedicle screws and decompression. Preoperative planning involved performing a cervical spine CT scan followed by 3D reconstruction using specialized software. This produced a 3D model of each vertebra, reflecting the patient's unique anatomy. Subsequently, we prepared the screw trajectories on the reconstruction. A detailed examination of the entire reconstruction allowed for a comprehensive 3D model of the cervical spine with the intended construct. During the surgical procedure, the surgeon utilized augmented reality glasses to visualize the cervical spine reconstruction in 3D. This enabled real-time observation of screw trajectories, cuts, and the construct without manual manipulation. Evaluation was based on operative time, accuracy of screw placement relative to preoperative planning, and radiological assessment (CT scan). Results: The surgical procedure lasted 150 minutes. The placement of screws was facilitated by viewing the 3D model, which minimized manual adjustments and reliance on image intensification. Postoperative outcomes were uncomplicated: no neurological complications, resolution of paresthesias, and significant reduction in cervicobrachial neuralgias. The postoperative CT scan confirmed accurate screw positioning. Discussion: Augmented reality navigation achieved satisfactory results, comparable to those predicted during preoperative planning, with high precision in screw trajectories. The 3D reconstruction of the spine reduced operative time and enabled real-time visualization of predefined screw paths, facilitating easier manipulation of the construct. Conclusion: The integration of new technologies such as augmented reality and artificial intelligence represents the future of surgery. These innovations provide excellent results with minimal risk and render surgical procedures more reproducible. Yan Silva 1 , Jocelyn Blanchard 1 , Jerome Couture 1 , Julien Goulet 1 , Bernard LaRue 1 , Newton Pimenta 1 1 Université de Sherbrooke, Sherbrooke, Canada Introduction: Intraoperative Ultrasound (IoUS) has long been used in spine surgery, different approaches have been described. Here we aim to review it’s use for intradural pathologies and first report two rare cases where IoUS was fundamental for the surgical results. Materials and Methods: We conducted a literature review on Medline with the terms « intraoperative, ultrasound and spine surgery ». We searched for intradural spine pathologies where the IoUS was helpful. We also describe two cases, one intradural disc herniation (IdHD) and a spinal subdural abscess (SSA). Results: A male of forty three years, under conservative treatment for HD, started new onset of pain, MRI with gadolinium enhancement showed an HD with posterior ligament tear and suspicion of an intra-dural herniation. Laminectomy was performed and the IoUS was used before dura incision to identify the HD and plan for intra dural approach. A female of fifty two years, drug user, presented with fever, mechanical back pain and dispnea. Under treatment for endocarditis, MRI suspected spondylodiscitis and epidural abscess. After laminectomy, no abscess were found in epidural space. IoUS was used to access dural space before durotomy for abscess decompression. Conclusion: Several studies show the benefice of IoUS for epidural pathology, intradural tumors in cervicothoracic region, for evaluation of decompression an even helping in fracture reduction. Our study is the first, to our knowledge, to address IoUS for two rare non-oncological intradural conditions and shows an important role for intraoperative diagnosis, approach choice and length of durotomy. Dmitry Dzukaev 1 , Alexander Peyker 1 , Anton Borzenkov 1 , Mikhail Safronov 1 , Georgiy Malyakin 2,3 , Eduard Bezuglov 2,3 1 Moscow Spine Center, City Clinical Hospital 67, Moscow, Russian Federation , 2 Sechenov First Moscow State Medical University , High Performance Sports Laboratory, Moscow, Russian Federation , 3 Sechenov First Moscow State Medical University, Department of Sports Medicine and Medical Rehabilitation, Moscow, Russian Federation Introduction: We describe a new surgical treatment technique using a clinical case study of the treatment of single-level lumbar stenosis in an adult professional football player, leader of the top-30 FIFA national football team. The presented technique consisted of a minimally traumatic minimally invasive transaponeurotic access for implant placement and decompression, as well as the use of semi-rigid PEEK rods, which allowed the patient to return to competitive activity only 1 month after surgical treatment and to continue to perform at the professional level without restrictions. Material and Methods: The method of transaponeurotic approach using the original instruments we developed (median skin incision followed by the use of the original developed retractor, minimal aponeurosis incisions for screw insertion and decompression without skeletonization of the posterior support complex), unilateral microsurgical decompression of neural structures with preservation of the posterior support complex, in combination with semi-rigid stabilization without detachment or damaging of the muscle tissue allowed the patient to resume training process in a week after the operation without restrictions, and to return to full-fledged competitive activity in a month (32 days). Microsurgical decompression in combination with semi-rigid stabilization does not require long period of time until formation of a full-fledged spondylodesis, and makes it possible to return to active physical activity already after wound healing (skin scar formation). We also must note that suggested implant insertion and rod placement method is more ergonomic and less traumatic for soft tissues than in the standard transcutaneous technique. A small medial cutaneous cosmetic suture looks more inconspicuous and aesthetic. Results: Pain intensity was assessed using the VAS scale and impairment was assessed using Oswestry. The preoperative VAS score was 10 points, which was interpreted as intense pain; according to the Oswestry questionnaire, the preoperative quality of life impairment score was 52%, which corresponded to a severe impairment (the patient's pain becomes the main problem, the activity of daily life is difficult for the patient). In the postoperative period, the VAS score is not higher than 0 points, respectively Oswestry result is 0%. Conclusion: The method of surgical treatment described in this clinical observation was applied in our clinic in 14 other patients, who also returned to active life without restrictions within 2-3 weeks. We emphasize in this abstract on the case of treatment of a professional football player due to the fact that the effectiveness of this technique is demonstrated in the face of maximum stress loads. We have implemented a unique method of surgical treatment of sportsmen patients, which consists in low-traumatic transaponeurotic access, careful microsurgical decompression of neural structures, and subsequent reliable prosthesis of the posterior support complex with semirigid implants, which allowed the elite sportswoman to return to sports and continue her professional career 1 month after the operation, which would have been impossible with any other surgical method. Bahador Athari 1 , Henry Avetisian 1 , Jordan Gasho 1 , David McCavitt 1 , Marc Abdou 1 , William Karakash 1 , Andy Ton 2 , Jeffrey C. Wang 1 , Raymond Hah 1 , Ram Alluri 1 1 Keck School of Medicine of USC, Department of Orthopaedic Surgery, Los Angeles, United States , 2 University of California, Irvine, Department of Orthopaedic Surgery, Irvine, United States Introduction: Spine surgery is a rapidly evolving surgical subspecialty, driven by continual advances in intraoperative techniques, implants, and imaging. Surgeons rely heavily on the medical literature to evaluate emerging approaches and hardware best suited for their patients. Therefore, assessing the quality of this literature is critical. The Level of Evidence (LOE) rating system, introduced in 1989 by David Sackett, offers a structured framework for evaluating research quality. In this hierarchy, randomized controlled trials are rated as Level I or II, cohort studies as Level II or III, case series as Level IV, and expert opinion studies as Level V. This study aims to evaluate the LOE in the spine surgery literature compared to other orthopaedic subspecialties. Methods: The PUBMED database (National Institutes of Health, Bethesda, MD) was electronically searched in February 2024 to retrieve all published articles between 2019 and 2023 in the following journals: The Journal of Arthroplasty , Spine, Foot & Ankle International , The Journal of Hand Surgery , the Journal of Shoulder and Elbow Surgery , the Journal of Pediatric Orthopaedics , the Journal of Orthopaedic Trauma , The American Journal of Sports Medicine , and The Journal of Bone & Joint Surgery . These journals were selected because they had the highest impact factor within their respective subspecialty. Exclusion criteria included animal studies, cadaver studies, basic science articles, review articles, case reports, and expert opinions. Results: The initial search yielded 17,323 articles, of which 12,818 met the inclusion criteria. The mean LOE within Spine was 3.091, which represents lower-quality evidence than The Journal of Arthroplasty (2.992), The Journal of Bone and Joint Surgery (2.962), and the American Journal of Sports Medicine (3.021). Additionally, only 16.0% of the articles in Spine were considered high evidence (LOE I & II), compared to 17.0% in the Journal of Pediatric Orthopaedics , 18.1% in The Journal of Arthroplasty , 24.9% in The Journal of Bone & Joint Surgery , 17.4% in Foot & Ankle International , and 21.1% in The American Journal of Sports Medicine . Discussion: Our findings suggest that the quality of research published in Spine lags behind other orthopaedic subspecialties, with fewer high-level of evidence studies. This highlights the need for initiatives to elevate the quality of spine surgery research and encourage the publication of higher level-of-evidence studies, namely randomized, controlled trials. Yong Hai 1,2 , Zihe Feng 1,2 1 Beijing Chaoyang Hospital, Capital Medical University, Beijing, China , 2 Center for Spinal Deformity, Capital Medical University, Beijing, China Background and Purpose: Robotic-assisted techniques have emerged as a promising advancement in complex spinal deformity surgery, potentially offering improved pedicle screw placement accuracy and surgical outcomes. This study aims to evaluate the efficacy and safety of robotic-assisted spinal surgeries in complex spinal deformity correction by analyzing recent literature and surgical experiences at Beijing Chaoyang Hospital. Methods: We reviewed recent systematic reviews and meta-analyses on robotic-assisted spinal deformity surgery. Additionally, we conducted two retrospective analyses at Beijing Chaoyang Hospital: (1) comparing robotic-assisted (RA) versus fluoroscopy-assisted (FA) surgeries in severe complex spinal deformity correction (n = 17 per group), and (2) comparing RA surgeries between severe complex deformity (SCD, n = 15) and non-severe deformity (NSD, n = 23) patients. Outcomes included pedicle screw accuracy, intraoperative blood loss, complication rates, correction effectiveness, and hospital stay duration. Results: Recent studies indicate that robotic systems enhance pedicle screw placement accuracy compared to traditional methods, particularly in challenging cases. Our first comparison showed significantly higher pedicle screw accuracy in the RA group compared to the FA group, with trends towards reduced blood loss and complications. The second comparison revealed no significant differences between SCD and NSD groups in screw accuracy or main curve correction rates, although SCD patients had longer hospital stays. Conclusions: Robotic-assisted surgery significantly enhances pedicle screw placement accuracy in severe complex spinal deformity correction compared to traditional methods, achieving comparable outcomes to non-severe cases. While showing potential in reducing blood loss and complications, further high-quality studies are necessary to substantiate its clinical benefits and optimize its application in spinal deformity surgery. Future developments aim to integrate AI and machine learning to extend robotic capabilities, potentially elevating the safety and efficacy of complex spinal deformity surgeries. Mert Dagli 1 , Yohannes Ghenbot 1 , Daksh Chauhan 1 , Hasan Ahmad 1 , Ryan Turlip 1 , Jaskeerat Gujral 1 , Kevin Bryan 1 , William Welch 1 , Ali Ozturk 1 , Jang Yoon 1 1 University of Pennsylvania Perelman School of Medicine, Philadelphia, United States Introduction: The intersection of artificial intelligence (AI) and healthcare has opened avenues for improved patient care and engagement, particularly in the surgical domain. As AI models become increasingly sophisticated, their role in preoperative and postoperative settings is a subject of considerable interest. Objectives: This study aimed to evaluate the clinical accuracy, relevance, clarity, and emotional sensitivity of Large Language Models (LLM) responses to general surgical patient questions. Methods: A questionnaire including 38 surgery-related general patient questions was formulated, based on input from three neurosurgical attendings. On August 16, 2023 these questions were used as single-shot inputs for three state-of-the-art LLMs: OpenAI’s ChatGPT GPT-4, Antropic’s Claude 2, and Google’s Bard. Two blinded research fellows independently evaluated the responses using a 5-point Likert scale to grade accuracy, relevance, and clarity, while emotional sensitivity was rated on a 7-point scale. Statistical methods, including the Shapiro-Wilk, Levene, Kruskal-Wallis, ANOVA, and post-hoc comparisons with Bonferroni corrections via Dunn and Tukey tests, were used to analyze the data. The inter-rater reliability was quantified through weighted percentage agreement (WPA). Results: Claude 2’s responses scored highest in all categories, with significant differences noted in accuracy (H = 27.464, p < .001), relevance (H = 29.074, p < .001), clarity (H = 32.745, p < .001), and emotional sensitivity (F = 10.799, p < .001). Non-normal distribution was detected for the scores of accuracy, relevance, and clarity (Shapiro-Wilk p < .05). Non-homoscedasticity was found in relevance (F2 = 5.009, p = .008). While no significant difference was found between ChatGPT and Bard in most categories, except in clarity (Z = 1.972, p = .038), Claude 2 notably outperformed both in pairwise comparisons (p < .05). Claude 2 demonstrated the highest WPA across the board, reflecting a strong agreement between raters. Conclusions: The study indicates that AI holds significant promise in accurately and efficiently responding to a diverse range of surgical patient inquiries. Hasan Ahmad 1 , Daksh Chauhan 1 , Ryan Turlip 1 , Omkar Anaspure 1 , Harmon Khela 1 , Robert Subtirelu 1 , Kevin Bryan 1 , Yohannes Ghenbot 1 , Connor Wathen 1 , Jang Yoon 1 , Prabaha Sikder 1 1 University of Pennsylvania Perelman School of Medicine, Philadelphia, United State s Introduction: Spinal fusion, a critical surgical intervention, often uses Polyetheretherketone (PEEK) cages for mechanical stability and pain relief. However, PEEK cages face high failure rates, low bioactivity, and bacterial infections. Integrating bioactive ceramics with Fused Filament Fabrication (FFF) technology offers a promising solution. This combination is expected to enhance osseointegration, reducing implant failure and infection risks. Objective: In this study, we rigorously evaluate the biocompatibility, bioactivity, and antibacterial properties of Bio-PEEK, aiming to establish a new standard in spinal implant technology and improve patient outcomes. Methods: Biocompatibility was assessed using inductively coupled plasma (ICP) analysis. Mouse pre-osteoblasts were seeded onto the filaments, and cages were immersed in Simulated Body Fluid (SBF) at 37°C for 7 days to compare bone-like apatite deposition. Cell growth kinetics were measured using a Thiazolyl blue tetrazolium bromide (MTT) assay. Antimicrobial properties were assessed with LIVE/DEAD analysis, and biofilm formation was examined using scanning electron microscopy (SEM) to compare S. aureus adherence on Bio-PEEK and bare PEEK. Results: Bio-PEEK showed improved biocompatibility and bioactivity over PEEK, with higher cell adhesion and bone-like apatite deposition. It exhibited faster cell growth kinetics and lower bacterial growth in LIVE/DEAD analyses. SEM images indicated Bio-PEEK's superior inhibition of biofilm formation, with fewer S. aureus adhering to Bio-PEEK compared to bare PEEK. Conclusion: Bio-PEEK demonstrated enhanced biocompatibility, bioactivity, and antibacterial properties compared to traditional PEEK. This improvement could reduce the need for costly bone-stimulating proteins, simplifying and lowering the cost of spinal fusion surgeries. Additionally, Bio-PEEK's enhanced antibacterial properties may decrease the risk of post-operative infections, improving patient recovery and implant success. Bio-PEEK marks a significant advancement in medical implants, promising more functional and cost-effective solutions in spine surgery and aligning with the trend towards personalized, patient-specific implants. Ibrahim Hussain 1 , Mousa Hamad 2 , Sudesh Srivastav 3 , Roger Härtl 2 1 Weill Cornell-New York Presbyterian, New York, United States , 2 Weill Cornell-New York Presbyterian Hospital, New York, United States , 3 Tulan Universtiy, New Orleans, United States Introduction: Segmental spinal movement or inadvertent movement of a spinal reference array frequently require re-scanning the spine in navigated or robotic spinal procedures. We assessed the reproducibility of a rapid 1 min re-registration technique using a novel Augmented Reality (AR) spine system. Methods: A lumbar spine phantom was scanned using an intra-operative cone beam CT scanner (GE OEC 3D, GE Healthcare, Salt Lake City, UT). A novel Augmented Reality (AR) guidance system (OnPoint Surgical, Inc., Concord, MA) was used to register the scan in a coordinate system of a spinal reference frame. Registration was performed using a surface scan collecting 100 surface points in 3 different anatomic regions, selected by the surgeon based on intra-operative exposure. We used the right transverse process, portion of the spinous process, and left transverse process at L3 for the registration. Each registration area was approximately 1cm 2 in size. The registration error in mm was measured by placing a pointer on the physical bone surface; software then measured the distance between the tracked pointer tip on the physical bone surface and the CT surface generated from the cone beam CT scan. The mean registration error was measured for the L3 left and right pedicle entry area. The mean registration error was measured 1.) for the initial registration, 2.) after placing a shim underneath the L3 vertebral body simulating segmental spinal movement during surgery, and 3.) following re-registration. The reproducibility or precision error of the re-registration was computed as the Root Mean Square Error (RMSE) = Sum of the Errors Squared / Count of Errors. Results: Mean and standard deviation (SD) (in mm) for 1.) initial registration, 2.) segmental spinal movement with shim, and 3.) re-registration for the left pedicle and right pedicle are as follows: 1.) Initial registration left and right: Mean 0.04, SD 0.16 and mean 0.08, SD 0.16; 2.) Registration error after vertebral movement with shim left and right: Mean 2.10, SD 0.61 and 2.39 and SD 0.53; 3.) Registration error post re-registration left and right: Mean 0.08, SD 0.14 and mean 0.06, SD 0.18. The precision error of the re-registration measured as RMSE was for the left and right side 0.15 and 0.18mm, respectively. Conclusion: In addition to directly registering intra-operative 3D scans, the novel AR system supports also surface registration of pre- and intra-operative CT scans. In the event of segmental spinal movement, e.g. from placement of an interbody device, a pre-operative CT or intra-operative spin can be re-registered within approximately 1 min with sub-millimeter precision. The rapid re-registration is precise and particularly advantageous in the presence of segmental movement or inadvertent movement of the spinal reference array, obviating the need for a re-spin with the potential to save 15-20 min of OR time. Baris Peker 1 , Hamisi Mraja 2 , Tunay Sanli 2 , Sepehr Asadollahmonfared 2 , Enas Daadour 2 , Mehmet Zamanoglu 2 , Onur Levent Ulusoy 2 , Selhan Karadereler 2 , Meric Enercan 1 , Azmi Hamzaoglu 2 1 Demiroglu Bilim University, Istanbul, Turkey , 2 Scoliosis and Spine Center - İstanbul, Istanbul, Turkey Introduction: Giant calcified thoracic disc herniation (GCTD) causing severe canal stenosis and myelopathy is a rare condition that can lead to significant neurological deficits. Traditionally, anterior decompression through a thoracotomy has been performed for surgical management. Posterior-only approach eliminates anterior thoracotomy and avoids related morbidity. The aim of this study is to evaluate the safety and efficacy of partial vertebrectomy performed with posterior-only approach for GCTD with myelopathy. Material and Methods: Patients who underwent posterior-only partial vertebrectomy for Giant calcified thoracic disc herniation with min 2 years f/up were included. Following instrumentation, wide laminectomy, and facet resection, the ipsilateral pedicle was resected. Partial vertebrectomy was carried cranially using high-speed drill until an adequate space was created underneath calcified thoracic disc herniation. Finally, Giant calcified thoracic disc herniation is cautiously dissected from the dura and resected en-block using a reverse curette. According to the size and location of calcified thoracic disc herniation, partial vertebrectomy was done bilaterally. Preop axial CT scans were used to measure the spinal canal occupation ratio. Neurological evaluation was done using the mJOA scale. Results: 21 (4M, 17F) pts with a mean age 47 (27-85) yrs and f/up was 62 (28-168) m. Giant calcified thoracic disc herniation was located mid-thoracic (T5-T8) in 5 pts and lower thoracic (T9-T12) in 16 pts. Canal compromise was central in 13 pts and paracentral in 8 pts. Preop spinal canal occupation ratio was a mean of 43.3% (18-64). Post-CT scans showed complete decompression and removal of GCTD in all pts. Dural tear (3pts-14%) was the most common complication. All of the 14 (66%) pts who had preop neurological deficits showed improvement postop. 5 of them fully recovered neurologically. Preop mean mJOA score improved from 12.7 to 16.8. None of the pts developed new-onset neurological deficits postop. Conclusion: Posterior-only partial vertebrectomy was a safe and effective method that provides a circumferential (360°) decompression of the spinal cord in pts with calcified thoracic disc herniation causing severe canal stenosis and myelopathy. This technique eliminates the anterior surgery and related complications. All pts in the series showed significant neurological improvement (mJOA 12.7 to 16.8) and none of the pts had new iatrogenic deficit postop. Angela Carrascosa 1 , Ignacio Dominguez 1 , Juan Castaño Montoya 1 , Rafael Luque Perez 1 , Jose Luis Perez Gonzalez 1 1 Hospital Clinico San Carlos, Madrid, Spain Introduction: Potential complications associated with screw malposition may result in neurological deficit or vascular injuries. The advantages of applying robotic technology in spine surgery include the possibility of improving screw accuracy, reducing complications, decreasing fluoroscopy use. Methods: The aim of this study was to assess the accuracy of pedicle screw placement, fusion rates and complications rates in adult patients with degenerative disorders of the thoracic and lumbar spines who have undergone robotic/navigated spinal surgery. The authors reviewed retrospectively collected data on 118 adult patients who had pedicle screws implanted with robot/navigated assistance using the ExcelsiusGPS system between September 2020 and September 2024. Pedicle screws were implanted by 4 experienced spinal surgeons after completion of a learning period. Results: A total of 548 pedicle screws were implanted in 118 patients; all the totality screws were placed robotically. The accuracy of pedicle screw placement was determined using intraoperative 3D fluoroscopy. In all patients a postoperative computed tomography scans were requested systematically. The accuracy rate of robot placed screw was 99.45%. Tree screws in different patient were determined to be Gertzbein and Robbins grade B, both patients without symptoms of sciatica and no adverse clinical sequalae were noted in the follow up. Two infections were found (0.36 %) and one required material removal (0.18%). The rate of screw malpositioning was a 0.547% and the fusion rates was 96.36%. Conclusion: This study demonstrates a high level of successful surgeon/assessed pedicle screw placement navigated robot/assisted, with no malpositions requiring a return to the OR. Everardo Escamilla 1 1 Hospital General Dr. Aquiles Calles Ramirez, ISSSTE, Tepic, Nayarit, Mexico Introduction: Virtual, Augmented reality and mixed reality has recognized as a valuable tools in spine surgery. We provide an overview of the key developments and technological milestones that have laid the foundation for Virtual, Augmented reality and mixed reality applications in this field and described how we use this technology in a single hospital in Mexico. We also assess the quality of existing studies on Virtual, Augmented reality and mixed reality systems in spine surgery and explore potential future applications. The purpose of this narrative review is to examine the role of Virtual, Augmented reality and mixed reality in spine surgery. It aims to highlight the evolution of Virtual, Augmented reality and mixed reality technology in this context, evaluate the existing body of research, and outline potential future directions for integrating Virtual, Augmented reality and mixed reality into spine surgery in a single hospital in Mexico. Material and Methods: Narrative, we describe a novel method to use virtual, augmented and mixed reality in spine surgery in General Hospital Dr. Aquiles Calles Ramirez, ISSSTE in Tepic, Nayarit, Mexico. Results: The use of this technologies has the potential for Virtual, Augmented reality and mixed reality to enhance spine surgical education and speculates on future applications to improve better outcomes for patients. Conclusions: Virtual, Augmented reality and mixed reality has emerged as a promising adjunct in spine surgery, with notable advancements and research efforts. The integration of Virtual, Augmented reality and mixed reality into the spine surgery operating room holds promise, as does its potential to revolutionize surgical education. Future applications of Virtual, Augmented reality and mixed reality in spine surgery may include real-time navigation, enhanced visualization, and improved patient outcomes. Continued development and evaluation of AR technology are essential for its successful implementation in this specialized surgical field. Keywords: Augmented reality; Computer-assisted spine surgery; Mixed reality; Stereotactic. Luciano Carneiro Filho 1 , Rafael Silva 1 , João Gonzalez 1 , André Nishizima 1 , Akio Donato 1 , Kenzo Donato 1 , Gabriela Nunes e Brito 1 , Adriano Silva 2 1 Bahiana School of Medicine and Public Health, Salvador, Brazil , 2 Itaigara Memorial (Grupo Onco Clinicas), Salvador, Brazil Introduction: Chronic back and leg pain is a debilitating condition that significantly impacts the quality of life for millions of individuals worldwide. Recent advancements have led to the development of Closed-Loop Spinal Cord Stimulation (CL-SCS), which offers a novel approach by continuously monitoring and adjusting the stimulation based on evoked compound action potentials (ECAPs). This real-time feedback mechanism ensures that the spinal cord activation remains within the therapeutic window, potentially leading to more consistent and effective pain relief. Therefore, the objective of this systematic review is to evaluate the effectiveness of CL-SCS in providing pain relief for individuals suffering from chronic back and leg pain. Methods: This systematic review followed the PRISMA 2020 protocol criteria. PubMed, Web of Science, and EMBASE databases were searched until September 20, 2024. Randomized controlled trials, cohort and observational studies associating closed-loop spinal cord stimulation with chronic back and leg pain were included. The main outcome assessed was the effectiveness of CL-SCS in pain. Results: A total of 120 studies were analyzed, of which 3 met the inclusion criteria for this review. The combined participant sample comprised 299 individuals, with a female-to-male ratio of 1.26. A cohort study involving 38 patients, followed over a 24-month period. After 24 months of treatment, the pain score, measured by a 100-mm Visual Analog Scale (VAS), showed a significant reduction [from 81.3 mm (±9.5) to 62.5 mm (±26.5), p < 0.001]. An observational prospective study included 148 participants who were permanently implanted with the ECAP-controlled CL-SCS system. Their main findings demonstrated a significant reduction in pain intensity over time, with mean pain scores (measured using the Verbal Numerical Rating Scale, VNRS) decreasing from a baseline of 8.2 ± 0.1 to 2.6 ± 0.2 at 3 months, 2.7 ± 0.3 at 6 months, and 2.6 ± 0.2 at 12 months post-implantation. A randomized clinical trial was conducted with 113 patients undergoing implantation (59 in the ECAP-controlled CL-SCS group and 54 in the open-loop SCS group). When comparing CL-SCS to open-loop SCS, the mean difference in pain reduction between the two groups was −12.9 (95% CI −22.4 to −3.4), with a p-value of 0.008, indicating a statistically significant difference in favor of the CL-SCS group. Conclusion: This systematic review demonstrates that Closed-Loop Spinal Cord Stimulation provides significant and sustained pain relief for individuals with chronic back and leg pain. Across the included studies, patients experienced consistent reductions in pain intensity over time, reinforcing the effectiveness of CL-SCS as a promising treatment option. However, further research is warranted to validate the long-term benefits and expand the clinical use of CL-SCS in broader patient populations. Marcel Castelo 1,2 , Johan Hurtado 3 , Luis Wilson 4 1 Hospital Antonio Lorena, Department of Neurosurgery, Cusco, Peru , 2 Universidad Nacional San Antonio Abad del Cusco, Cusco, Peru , 3 Hospital Antonio Lorena, Department of Neurosurgery, Department of Neurosurgery, Cusco, Peru , 4 Hospital Antonio Lorena, Department of Otorrinolaryngology, Cusco, Peru Introduction: Olfactory ensheathing cells transplanted into the injured spinal cord in animals promote regeneration and remyelination of descending motor pathways through the site of injury and the return of motor functions. There are considerable disagreements on the application of olfactory ensheathing cells (OEC) for spinal cord injury (SCI) rehabilitation in human spinal cord injury. We don´t know of published previous experiences in our country, hence our objective is to present a single experience of autologous mucosal OEC transplantation in a patient with chronic complete (ASIA classification A) spinal cord injury (SCI). Material and Methods: One male individual with traumatic SCI of the thoracolumbar spine, previously operated for unstable fracture 3 years before, was selected to take a sample from his autologous OEC (by otorhinolaryngologist) and implant directly into the spinal cord scar (by neurosurgeons). All adverse events and possible functional outcomes were documented performing pre- and post-operative general clinical examination and magnetic resonance imaging (MRI), neurological assessment based on the International Standard of Neurological Classification for SCI (ASIA scale). The surgical plan was submitted to the institutional ethics committee for approval. Results: No serious neurological issue (deterioration or new symptoms) or complication were recorded during the 5 years of follow-up. MRI findings remained almost unchanged with no tumoral tissue formation (cyst, syrinx or myelitis) to indicate that the procedure is unsafe. ASIA improved from A to C in the patient, with strong improvement in his sensory scores as well as his autonomic control in his sphincter function at the end of the following period. Conclusions: This 5-year follow-up OEC implantation first experience was not associated with any adverse findings, which may suggest the safety of autologous OEC for the treatment of human SCI. We need to design a protocol for recruitment new cases to improve strategies for apply this technique focused on safety and advantageous cost/benefit relation.

Katherine Sage 1 , Justin Davis 2 , Brian Everist 2 , Casey Butrico 1 1 Kuros Biosciences, Atlanta, United States , 2 Kansas University Medical Center, Kansas City, United States Introduction: Iliac crest bone graft (ICBG) is the gold standard graft material for spinal fusion procedures to treat degenerative disc disease (DDD). Limitations in the availability of autograft and morbidity associated with an additional harvest procedure led to the development of synthetic bone grafts. A novel polymer embedded biphasic calcium phosphate bone graft with a submicron needle-shaped topography (BCP < µm) was developed to provide traction for pro-healing M2 macrophages. M2 macrophages stimulate stem cells to form new bone throughout the graft, promoting predictable fusion. The objective of this study is to evaluate the fusion rates with BCP < µm in Transforaminal Lumbar Interbody Fusion (TLIF) procedures to treat DDD. Material and Methods: A single-center, single-arm retrospective evaluation of 20 patients who received TLIFs with BCP < µm used standalone was initiated to evaluate fusion. Patients were evaluated with computed tomography (CT) scans, X-rays, and patient-centered outcome questionnaires at 12 months post-operative. X-rays and CT scans were interpreted by an independent physician blinded to the clinical status of the patients. Interbody fusion was evaluated based on the BSF Interbody Fusion Classification, with Grade 1 characterized as “not fused” and Grades 2 and 3 characterized as “fused”. Results: Of the 20 subjects, 11 were females and 9 were males. The average age of participants was 67.2, and the average BMI was 32.30. Six participants (30%) underwent previous lumbar surgery, 7 (35%) had diabetes, and 11 (55%) were former or current smokers. Thirty-six total levels were fused with an average of 1.8 fusions per subject. Seventeen subjects had only interbody fusions, and 3 patients had interbody and posterolateral fusions. An average of 2.0 cc [range 1.125-3.3 cc] of BCP < µm was grafted per level in the interbody space. At 12 months post-operative, 34/36 (94.4%) of levels were deemed fused, and 2/36 (5.6%) levels were not fused. The unfused levels were likely due to infection and multiple comorbidities. There were three adverse events (AEs) reported that were not associated with the bone graft. The change in average VAS score was 2.5/10 (25%), and all patients who reported pre-operative leg and back pain reported an improvement at 12 months. Conclusion: BCP < µm demonstrated high fusion rates at 12 months post-operative in a challenging patient population. TLIF fusion was accompanied by improvements in VAS pain scores as well as post-operative back and leg pain improvement. This study reports favorable fusion outcomes with a standalone calcium phosphate bone graft alternative to ICBG for interbody procedures. Katherine Sage 1 , Pierce Nunley 2 , Milo Sanda 2 , David Cavanaugh 2 , James Ryaby 1 , Marcus Stone 2 1 Kuros Biosciences, Atlanta, United States , 2 Louisiana Spine Institute, Shreveport, United States Introduction: This ambispective evaluation and analysis of a single-center cohort aimed to evaluate the performance of a novel biphasic calcium phosphate (BCP) bone graft with submicron-sized needle-shaped surface topography (BCP < µm) in interbody arthrodesis of the lumbar spine. Material and Methods: This study was a single-center ambispective assessment of adult patients receiving BCP < µm as part of their lumbar interbody fusion surgery. The primary outcome was a fusion status on computed tomography (CT) 12 months postoperative. The secondary outcomes included postoperative changes in the visual analog scale (VAS), Oswestry Disability Index (ODI), Short Form 12 (SF-12), and length of stay (LOS). Results: Sixty-three patients with one- to three-level anterior (48, 76%) and lateral (15, 24%) interbody fusions with posterior instrumentation were analyzed. Thirty-one participants (49%) had three or more comorbidities, including heart disease (43 participants, 68%), obesity (31 participants, 49%), and previous lumbar surgery (23 participants, 37%). The mean ODI decreased by 24. The mean SF-12 physical health and SF-12 mental health improved by a mean of 11.5 and 6.3, respectively. The mean VAS for the left leg, right leg, and back improved by a mean of 25.75, 22.07, and 37.87, respectively. Of 101 levels, 91 (90%) demonstrated complete bridging trabecular bone fusion with no evidence of supplemental fixation failure. Conclusion: The data of BCP < µm in interbody fusions for degenerative disease of the lumbar spine provides evidence of fusion in a complicated cohort of patients Jehwi Yun 1 , Pyunggoo Cho 1 1 ajou University Medical Center, Neurosurgery, Suwon, South Korea Introduction: Achieving successful fusion is critical for patient outcomes. Since numerous factors can affect the fusion rate, choosing graft material is one of the most important factors. The (Bioactive glass ceramic) BGC spacer is a synthetic glass-ceramic spacer and has osteoactive material properties. And ABM/P-15 Osteogenic peptide bone graft, is a composite bone substitute material consisting of P-15 synthetic collagen fragment, which enhances cell migration and induces osteoblast cell proliferation and differentiation. We aimed to evaluate the effectiveness by comparing fusion rates of using the BGC spacer alone versus the spacer combined with ABM/P-15 Osteogenic peptide in single-level ACDF. Methods: This retrospective cohort study included 147 patients who underwent ACDF from January 2020 to March 2024. Excluding multi-level cases and Posterolateral fusion combined cases, 96 patients who had single-level ACDF without additional posterolateral fusion were included in the analysis. Patients were divided into two groups: the BGC group (41 patients) who received the BGC spacer alone, and the BGC + ABM/P-15 Osteogenic peptide group (55 patients) who received the BGC spacer combined with ABM/P-15 Osteogenic peptide. Patient demographics, surgical details, and clinical outcomes including fusion were collected. Fusion was assessed using C-spine X-ray flexion-extension views which taken at postoperative 6 and 12 months. Two neurosurgeon measured the interspinous process distance and assessed the difference between flexion and extension to confirm fusion. Results: The mean age of the group was 57.39 years (SD 14.603). In the BGC + ABM/P-15 Osteogenic peptide group, the mean age was 59.15 years (SD 13.512), and the BGC group, it was 55.30 (SD 15.674). At the 6-month follow-up, BGC + ABM/P-15 Osteogenic peptide group got 20 patients (62.5%) showing successful fusion. While the BGC group, 27 patients were evaluated, with 12 patients (44.4%) showing fusion. At the 12-month follow-up, 22 patients in the BGC + ABM/P-15 Osteogenic peptide group were evaluated, resulted with 20 patients (90.9%) showing fusion. In the BGC only group, with 20 patients, 16 patients (80%) shown fusion. Any difference of adverse effect was not noticed between two groups. Discussion: The findings of this study suggest that using ABM/P-15 Osteogenic peptide in combination with the BGC spacer seems to be more effective and faster than using the BGC spacer alone in achieving fusion at single-level ACDF. The addition of ABM/P-15 Osteogenic peptide may provide additional benefits without increasing morbidity, supporting its use as a viable alternative to traditional allografts. These results are consistent with previous studies that have demonstrated the efficacy of ABM/P-15 Osteogenic peptide in enhancing bone healing and fusion rates. Conclusion: The use of BGC spacer with ABM/P-15 Osteogenic peptide provides superior fusion rates and clinical outcomes to the use of BGC spacer alone in ACDF, with a similar safety profile. This study supports the use of ABM/P-15 Osteogenic peptide as an effective and safe addition to interbody fusion devices for single-level ACDF. Further studies with larger sample sizes and long-term follow-up are recommended to confirm these findings and explore the potential benefits of ABM/P-15 Osteogenic peptide in multi-level ACDF procedures. Tomer Korabelnikov 1 , Lisa Tamburini 1 , Rohan Patel 1 , Raghunandan Nayak 1 , Kelly White 1 , Joellen Broska 1 , Isaac Moss 1 , Scott Mallozzi 1 , Hardeep Singh 1 1 UConn Health, Department of Orthopedic Surgery, Farmington, United States Introduction: Spinal fusion is frequently used to treat mechanical back pain or radicular symptoms due to degenerative disease. Pseudoarthrosis remains a persistent challenge, leading to poor clinical outcomes and often revision surgery. To enhance fusion rates, surgeons increasingly rely on biologics, such as Bone Morphogenic Protein (BMP). Despite its effectiveness in promoting bone growth, BMP's use has declined due to associated complications such as osteolysis, retrograde ejaculation, inflammatory reaction, and ectopic bone formation. i-Factor, a peptide-enhanced bone graft substitute, has been shown to promote successful fusion while offering a more favorable side effect profile to BMP in single-level anterior cervical discectomy and fusion (ACDF) procedures. Despite these findings, limited data exists on the use of i-Factor in transforaminal lumbar interbody fusion (TLIF) procedures. Material and Methods: A retrospective chart review was conducted for patients who underwent spinal fusions between May 2018 and June 2024. They were categorized based on the biologic used: i-Factor, BMP, and no augmentative biologic (control). The control cohort was size-matched to i-Factor and BMP. Only patients undergoing TLIF procedures were included. Patients on other biologics prior to or after surgery were excluded. Data on fusion rates at 1 year, complications rates, and demographics such as age, sex, BMI, number of levels, length of stay, OR time, smoking status, and concomitant surgeries were collected. Results: 145 patients were included: 92 patients received i-Factor, 34 received BMP, and 19 in the control cohort. There were no significant demographic differences between cohorts. Patients for which 1 year data was available, fusion rates were not statistically different: 95.83% (i-Factor), 96.30% (BMP), 100% (control) (p = 0.760). The BMP cohort had longer OR times, more levels operated on, and longer lengths of stay compared to control and i-Factor (p < 0.001). These variables were correlated with each other (p < 0.001). i-Factor was utilized in fewer revision procedures (p = 0.002), and patient who received i-Factor required fewer transfusions (p < 0.001), had fewer strokes (p = 0.008) and had a lower reoperation rates (p = 0.012) compared to BMP. When comparing complications of control to BMP and i-Factor, the only statistically significant association was lower transfusion rates in the i-Factor cohort over control (p = 0.016). Longer OR times were associated with revision procedures (p = 0.013), more transfusions (p < 0.001), and higher reoperation rates (p = 0.003). More levels operated on was associated with transfusions (p < 0.001). More levels operated on was not associated with revision procedures (p = 0.562) or reoperation rates (p = 0.517). Strokes were not associated with longer OR times (p = 0.070) or more levels operated on (p = 0.530). Conclusion: i-Factor as an augmentative biologic for TLIF procedures is statistically non-inferior to BMP and no biologic in terms of fusion rates at 1 year. It is difficult to attribute complications to the biologic itself as BMP was used in longer cases, more difficult cases involving more levels and more revision procedures. When accounting for these demographic differences, i-Factor still demonstrated a favorable safety profile reporting a lower stroke risk and reoperation rate compared to BMP. With potential to enhance patient outcomes while mitigating risks, i-Factor represents a promising advancement in spinal fusion surgery. Shi Ting Chiu 1 , Seah Jing Sheng Shawn 1 , Reuben Soh 1 1 Singapore General Hospital, Department of Orthopaedics Surgery, Singapore, Singapore Introduction: Recombinant human bone morphogenetic protein-2 (rhBMP-2) is widely used in lumbar spinal fusion surgery to stimulate fusion. However, there is an increasing number of reported complications such as end plate resorption, implant displacement, infection, radiculitis and erectile dysfunction. Escherichia coli-derived rhBMP2 (E.BMP-2) is an affordable formulation of rhBMP-2, but the optimal dosage to reduce risk of complications while still providing enhanced bone fusion has yet to be established. There is a paucity of studies evaluating the safety profile and clinical outcomes of E.BMP-2 usage in lumbar fusion. This study aims to compare clinical and radiological outcomes between CHO-rhBMP-2 and low dose E.BMP. Material and Methods: This is a single-center, single-surgeon, retrospective study of patients who underwent minimally invasive lateral lumbar spinal interbody fusion surgery (between L1 to S1) with low dose E.BMP 2 and CHO-derived rhBMP-2 bone grafts from 2018 to 2024. Patients in each group were matched and compared. The E.BMP-2 was first bound to calcium hydroxyapatite granules before being applied to the interbody space within a cage. Patient reported outcome measures (PROMs) such as the Numeric Pain Rating Scale (NPRS), Oswestry Disability Index (ODI) and 36-Item Short Form Health Survey (SF-36) were collated preoperatively and postoperatively at different time intervals. Post operative plain lumbar radiographs were also assessed for segmental lordosis and implant related complications. Interval CT lumbar spine scans were done to assess fusion rate using the Bridwell interbody fusion grading system. Results: A total of 81 patients and 166 levels were involved. There was no significant difference in baseline characteristics between the two groups. The average dosage of rhBMP-2 was 0.50 mg per level in the E.BMP-2 group and 1.91 mg per level in the rhBMP-2 group. There were no significant differences in terms of post-operative clinical outcome scores at various time intervals (3 months, 6 months, 1 year and 2 years). There was also no difference in terms of post-operative segmental lordosis. Fusion rates were assessed using both plain dynamic radiographs (flexion-extension views) and CT scans at latest follow up. Good fusion on plain dynamic film was defined as an absence of translational motion (> 3 mm) and angular motion (> 5 degrees). Fusion on CT scan was graded with the Bridwell interbody fusion grading system. Good fusion was defined as Bridwell grading of at least 2. All measurements were done by two independent investigators not involved in the surgery. Fusion rates on dynamic radiographs were 100% for both groups. Fusion rate on CT scan was 86.4% (n = 19) in the E.BMP-2 group while it was 78.3% (n = 18) in the rhBMP-2 group. None of our patients had any postoperative complications seen on scans or clinically. None of them required revision surgery as well. Conclusion: This study demonstrates that low dose E.BMP-2 use in lumbar spinal fusion surgery is not inferior to a traditionally available rhBMP-2. Higher fusion rate with lower dose of bone graft further highlights its efficacy. Low dose E.BMP-2 is thus a safe alternative osteo-inductive agent that can facilitate spinal fusion. John O'Toole 1 , Paul Arnold 2 , Michael Steinmetz 3 , Christopher Chaput 4 , Rick Sasso 5 , James Harrop 6 1 Rush University, Chicago, United States , 2 Loyola University, Chicago, United States , 3 Cleveland Clinic Lerner College of Medicine, Cleveland, United States , 4 University of Texas Health Science Center at San Antonio, San Antonio, United States , 5 Indiana University School of Medicine, Carmel, United States , 6 Thomas Jefferson University, Philadelphia, United States Introduction: Studies show nicotine use, obesity, and diabetes have negative effects on fusion, bone healing, and patient-reported outcomes. Patients with ≥ 1 of these co-morbidities may be considered higher-risk. Bone grafts may influence local biology to improve the environment for bone healing. ABM/P-15 Matrix (Cerapedics Inc., Westminster, Colorado, USA), an FDA breakthrough device, is a Class III composite bone graft incorporating P-15, a synthetic peptide mimicking the cell binding domain of Type I collagen. P-15’s mechanism of action is well-established with a long clinical history. This abstract compares the clinical success of ABM/P-15 Matrix to local autograft in instrumented transforaminal lumbar interbody fusion (TLIF) in higher-risk patients with degenerative disc disease (DDD) and up to Grade I spondylolisthesis using a prospective, multicenter, controlled, single-blinded, randomized pivotal study. Material and Methods: Skeletally mature patients, aged 22-80 years, with DDD were 1:1 randomized to either ABM/P-15 Matrix or local autograft during single-level TLIF with a PEEK cage and bilateral pedicle screw fixation. Composite Clinical Success (CCS), defined as having met all of the following success criteria at 24-months, was compared between treatment groups stratified by higher- and normal-risk: no index level secondary surgical intervention; achievement of fusion (evidence of bridging trabecular bone between vertebral bodies via thin-slice computed tomography); ≥ 15-point improvement in Oswestry Disability Index (ODI) from baseline; no new or worsening, persistent neurological deficit relative to baseline; and no serious device-related adverse events (AEs). Higher-risk was defined as having ≥ 1 risk factor (nicotine use, obesity, and/or diabetes). Results: A total of 290 patients from 33 sites were enrolled; 141 (48.6%) patients received ABM/P-15 Matrix and 149 (51.3%) patients received autograft. Both groups comprised 62.4% higher-risk patients. The higher-risk ABM/P-15 Matrix group had significantly higher CCS than the autograft group (52.1%, 37/71 versus 38.2%, 29/76, respectively, difference = 14.0%, 90% CI: 0.6%, 27.3%) and significantly higher fusion rate (81.3%, 61/75 versus 60.5%, 46/76, respectively, p = 0.005). The normal-risk ABM/P-15 Matrix group achieved significantly higher CCS than the autograft group (60.4%, 29/48 versus 36.5%, 19/52, respectively, 95% CI 17.1%, 48.8%) and significantly higher fusion rate (88.5%, 46/52 versus 56.6%, 30/54, respectively, p < 0.0002). In the higher-risk group, there was no significant difference between the treatment and control groups in the incidence of patients with no index level secondary surgical intervention, whereas in the normal-risk group, the autograft group had significantly more patients with no index level secondary surgical intervention. In both the higher- and normal-risk groups, there were no significant differences between treatment groups with respect to ODI improvement, neurological deficits (motor and sensory), and serious device-related AEs. Conclusion: A paucity of data exists evaluating the impact of bone graft biomaterials on fusion in higher-risk patients. Studies evaluating the impact of biologics often exclude higher-risk patients or they comprise a small proportion of the study population. In the present RCT, > 60% patients presented with ≥ 1 co-morbidity. The ABM/P-15 Matrix group achieved significantly higher CCS and fusion outcomes at the 2-year follow-up compared with the autograft control group in both the higher- and normal-risk groups. Bradley Jacobs 1 , Christopher Witiw 2 , Zhi Wang 3 , Perry Dhaliwal 4 , Carlo Santaguida 5 , Chris Bailey 6 1 University of Calgary, Calgary Spine Program, Calgary, Canada , 2 University of Toronto, Division of Neurosurgery, St. Michael's. Hospital, Toronto, Canada , 3 University of Montreal, Department of Orthopaedic Surgery, Montreal, Canada , 4 University of Manitoba, Section of Neurosurgery, Department of Surgery, Winnipeg, Canada , 5 McGill University, Department of Neurology and Neurosurgery, Montreal, Canada , 6 Western University, Division of Orthopaedics, Department of Surgery, London, Canada Introduction: Posterolateral Lumbar Fusion (PLF) is a commonly implemented procedure in the treatment of degenerative conditions in the lumbar spine. Successful arthrodesis is critical to favorable long-term outcomes. Both fusion technique and bone graft material choice have significant impact on arthrodesis. P-15 Peptide Enhanced Bone Graft (ABM/P-15 Matrix), is one such bone graft option that is a composite bone graft incorporating P-15, a synthetic peptide that mimics the cell-binding domain of Type I collagen. This abstract reports the early clinical and radiological outcomes associated with the use of ABM/P-15 Matrix in single and multi-level PLF procedures in a multi-center clinical trial. Materials and Methods: A prospective on-label study was conducted in six hospitals in Canada. Adult participants requiring lumbar spinal fusion with PLF, between levels L1-S1, were included. Neurological status, relevant clinical history, Oswestry Disability Index (ODI), 12-Item Short Form Survey (SF-12), and Numeric Pain Rating Scale (NRS) were collected at baseline, 6-months, 12-months and 24-months. Active smoking, obesity (BMI > 30) and diabetes were considered high-risk factors. A thin-cut (< 1 mm) CT was acquired at 12-months and assessed for fusion status by an independent core-lab (Medical Metrics Inc.). Fusion status was reported at both the segmental and participant level. Fusion status was reported at both the segmental and participant level, with fusion being defined as: absent fusion (no evidence of initial healing, consolidation or bridging bone), partial fusion (early signs of fusion) and fusion (presence of continuous bridging bone). Adverse events and reinterventions at the index level were recorded. Adverse events and reinterventions at the index level were recorded. Results: A total of 45 participants (62 operative levels) (mean years and standard deviation of age 67.9 ± 11.9; 14 male, 31 female) were included. 76% of patients presented with 1 or more high-risk comorbidities (16 with BMI > 30, 7 current smokers, 11 with diabetes). The mean number of levels operated was 1.4 (range 1 to 3). Of the 31 PLF participants with data available, 80.6% were either fully (n = 19) or partially (n = 6) fused at 12 months. Additionally, 97.7% of the 43 PLF segments were either fully (n = 35) or partially (n = 7) fused at 12 months. Mean improvement at 12 months was noted in ODI (p < 0.001), SF-12 mental score (p = 0.027), SF-12 physical score (p < 0.001), NRS back score (p < 0.001) and NRS leg score (p < 0.001). No adverse events were reported that were related to the device. Conclusion: Despite the biologically and mechanically challenging environment for posterolateral fusion and the high number of patients presenting with high risk co-morbidities (76% had at least 1 co-morbidity known to adversely impact fusion and clinical outcomes), high fusion rates at 12-months were observed with P-15 peptide enhanced bone graft. No evidence of graft related complications and no index level re-operations at 1 year postoperative. Bradley Jacobs 1 , Christopher Witiw 2 , Zhi Wang 3 , Perry Dhaliwal 4 , Carlo Santaguida 5 , Chris Bailey 6 1 University of Calgary, Calgary Spine Program, Calgary, Canada , 2 University of Toronto, Division of Neurosurgery, St. Michael's. Hospital, Toronto, Canada , 3 University of Montreal, Department of Orthopaedic Surgery, Montreal, Canada , 4 University of Manitoba, Section of Neurosurgery, Department of Surgery, Winnipeg, Canada , 5 McGill University, Department of Neurology and Neurosurgery, Montreal, Canada , 6 Western University, Division of Orthopaedics, Department of Surgery, London, Canada Introduction: Transforaminal Lumbar Interbody Fusion (TLIF) and Posterior Lumbar Interbody Fusion (PLIF) are common surgical techniques used to address degenerative conditions in the lumbar spine. Successful arthrodesis is critical to favorable long-term outcomes. Both fusion technique and bone graft material choice have significant impact on arthrodesis. P-15 Peptide Enhanced Bone Graft (ABM/P-15 Matrix), is one such bone graft option that is a composite bone graft incorporating P-15, a synthetic peptide that mimics the cell-binding domain of Type I collagen. This abstract reports the early clinical and radiological outcomes associated with the use of ABM/P-15 Matrix in single and multi-level TLIF or PLIFs in a multi-center clinical trial. Materials and Methods: A prospective on-label study was conducted in six hospitals in Canada. Adult participants requiring lumbar spinal fusion with TLIF/Posterolateral Fusion (PLF) or PLIF/PLF, between levels L1-S1, were included. Neurological status, relevant clinical history, Oswestry Disability Index (ODI), 12-Item Short Form Survey (SF-12), and Numeric Pain Rating Scale (NRS) were collected at baseline, 6-months, 12-months and 24-months. Active smoking, obesity (BMI > 30) and diabetes were considered high-risk factors. A thin-cut (< 1 mm) CT was acquired at 12-months and assessed for fusion status by an independent core-lab (Medical Metrics Inc.). Fusion status was reported at both the segmental and participant levels. Adverse events and reinterventions at the index level were recorded. Results: A total of 94 participants (116 operative levels) (27 male, 67 female, mean years and standard deviation of age for TLIF+PLF 61.5 ± 10.5 and PLIF+PLF 63.3 ± 10.6) were included and received either TLIF or PLIF procedures combined with instrumented posterior fusion (PLF). 60.6% of patients presented with 1 or more high-risk comorbidities (33 with BMI > 30, 7 current smokers, 17 with diabetes) . The mean number of levels operated was 1.2 for TLIF/PLF (range 1 to 3) and 1.2 for PLIF/PLF (range 1 to 2). Of the 52 TLIF/PLF participants with data available, 80.7% were either fully (n = 33) or partially (n = 9) fused. Additionally, 98.4% of the 61 TLIF/PLF segments were either fully (n = 46) or partially (n = 14) fused. Of the 17 PLIF/PLF participants, 88.2% were either fully (n = 13) or partially (n = 2) fused. Additionally, 95.0% of 20 PLIF/PLF segments were either fully (n = 17) or partially (n = 2) fused. Mean improvement for TLIF/PLF at 12 months was noted in ODI (p < 0.001), SF-12 mental score (p = 0.005) and SF-12 physical score (p < 0.001), NRS back score (p < 0.001) and NRS leg score (p < 0.001). Mean improvement for PLIF/PLF at 12 months was noted in ODI (p < 0.01), SF-12 mental score (p = 0.037), NRS back score (p < 0.001) and NRS leg score (p < 0.001). Conclusion: High fusion rates at 12-months in lumbar arthrodesis were observed with P-15 peptide enhanced bone graft, even in a population where a majority of the patients were considered high risk (at least 1 co-morbidity known to adversely impact fusion and clinical outcomes). No evidence of graft related complications and no index level re-operations were identified. Sajan Hegde 1 , Appaji Krishnan 1 , Vignesh Badikillaya 1 , Kunal Chanji 1 , Sakthivel Ramaswamy 1 1 Apollo Hospitals, Greams Road, Thousand Lights, Chennai, India Introduction: Anterior cervical discectomy and fusion, a procedure that treats nerve root or spinal cord compression in neck. Iliac crest bone graft is considered the gold standard for bone grafting in cervical fusion due to osteoconductive and osteoinductive properties. However, disadvantages include donor site morbidity. As an alternative to bone graft, autologous bone marrow aspirate is used to achieve fusion with satisfactory outcome. The aim of this study is to analyse the use of sternal bone marrow aspirate soaked gelatin sponge as fusion promoting adjunct to anterior cervical discectomy and fusion. Material and Methods: We retrospectively analysed 58 patients who underwent one-level or 2- or 3-level ACDF performed by a single surgeon for the treatment of degenerative disc disease, cervical spondylolisthesis, stenosis, cervical radiculopathy and myelopathy. 38 patients were operated at one level , 14 at two levels , 6 at three levels . around 4 ml of sternal bone marrow was aspirated and soaked in gelatin sponge and it was used .Patients are followed up at 3 months, 6 months, 1 year and 2 year. CT scan is used to assess fusion. Results: A total of 58 patients (male 36, female 22). 49 patients were evaluated, 9 patients lost follow up. Mean patient age was 48 years. The mean radiographic follow-up period was 16.4 months. Xrays and CT scans at one year follow up demonstrated fusion. 2 patients had cage subsidence. There were no reports of sternal donor site morbidity. Conclusion: Sternal bone marrow aspirate soaked in gelatin sponge facilitates fusion following anterior cervical discectomy and fusion. It is a easily accessible, low-cost, minimally invasive and less disruptive option which enhances the fusion rates with less complications. Luca Ambrosio 1 , Jordy Schol 2 , Shota Tamagawa 3 , Sathish Muthu 4 , Daisuke Sakai 2 , Rocco Papalia 1 , Gianluca Vadalà 1 , Vincenzo Denaro 1 1 Campus Bio-Medico University Hospital Foundation, Department of Orthopedic and Trauma Surgery, Rome, Italy, 2 Tokai University School of Medicine, Department of Orthopedic Surgery, Isehara, Japan, 3 Juntendo University Graduate School of Medicine, Department of Medicine for Orthopaedics and Motor Organ, Tokyo, Japan, 4 Government Medical College, Department of Orthopaedics, Karur, India Introduction: Lumbar spinal fusion (LSF) is a common surgical procedure for treating lumbar degenerative conditions. The use of osteobiologics has emerged as a promising alternative to enhance fusion and address the limitations of autologous iliac crest bone graft (AICBG), but their comparative efficacy and safety remain unclear. In this systematic review and network meta-analysis (NMA), we assessed the fusion rates, safety profiles, and clinical outcomes of different osteobiologics used in LSF, providing a comparative framework to identify the most effective and safe osteobiologic products to achieve a solid bony fusion. Material and Methods: A systematic search of PubMed/MEDLINE and Scopus was conducted for eligible studies published until March 2024 (PROSPERO CRD42024514566). Briefly, we sought randomized controlled trials (RCTs) including adults affected by lumbar degenerative disorders who underwent single or multi-level LSF augmented with osteobiologic(s) compared to the same procedure augmented with a different osteobiologic. Data on fusion rates, complications, and patient-reported outcomes (i.e., pain, disability, blood loss, operation time, and length of stay [LOS]) were extracted. The risk of bias was assessed using the Risk of Bias (RoB)-2 tool and the certainty of evidence was assessed using the GRADE framework. NMA employed a frequentist random effects model to compare the efficacy and safety of various osteobiologics, as well as related perioperative and clinical outcomes. Results: A total of 43 RCTs including 3823 patients were identified. The NMA revealed that recombinant human bone morphogenetic protein (rhBMP)-2 significantly improved fusion rates (OR: 3.71, 95% CI: 2.59-5.32, p < 0.00001) and reduced complications (OR: 0.46, 95% CI: 0.33-0.64, p < 0.00001) compared to AICBG, with moderate certainty of the evidence. Anorganic bone matrix/15-amino acid peptide fragment ([ABM/P-15], OR: 0.02, 95% CI: 0.00-0.41, p = 0.0117), allograft (OR: 0.04, 95% CI: 0.00-0.69, p = 0.0272), and allograft + bone marrow concentrate ([BMC], OR: 0.04, 95% CI: 0.00-0.99, p = 0.0468) were also associated with significantly lower complication rates, although the certainty of the evidence ranged from low to very low. No significant differences were observed among the osteobiologics regarding pain, disability, or LOS. rhBMP-2 (mean difference [MD]: -21.82 min, 95% CI: -27.99 to -15.65 min, p < 0.0001), ALB (MD: -12.00 min, 95% CI: -21.50 to -22.50, p = 0.0133), and SiCaP (MD: -18.42 min, 95% CI: -28.58 to -8.26, p = 0.0004) demonstrated to be significantly associated with reduced operation times. rhBMP-2 was also associated with a significantly lower blood loss (MD: -72.64 mL, 95% CI: -118.88 to -26.39 mL, p = 0.0021). Conclusion: This NMA found that rhBMP-2 is significantly associated with higher fusion and lower complication rates compared to AICBG, as well as lower operation time and blood loss. Other osteobiologics may also offer benefits, but the supporting evidence is limited and of low quality. Soroush Shabani 1 , Jordan Gasho 1 , Jadesola Olurin 1 , Brandon Yoshida 1 , Andy Ton 2 , Kevin Liu 1 , Zachary Singh 1 , Jeffrey C. Wang 1 , Ram Alluri 1 , Raymond Hah 1 1 Keck School of Medicine of USC, Orthopaedic Surgery, Los Angeles, United States , 2 UCI School of Medicine, Orthopaedic Surgery, Irvine, United States Introduction: Anterior cervical discectomy and fusion (ACDF) is the most common surgical treatment for cervical degenerative conditions. Traditionally, ACDF utilizes iliac crest autograft as a composite in the cage matrix. However, iliac crest autografts carry significant morbidity, leading to an increased use of local autografts, which often lack sufficient quality and volume. i-Factor Bone Graft, a composite substance that utilizes a novel peptide that mimics Type I collagen, has been developed to induce new bone formation. This study investigates the relationship between interbody graft material and the occurrence of pseudarthrosis. Materials and Methods: This was a retrospective cohort analysis analyzing patients at a single academic hospital undergoing ACDF from 2018-2022. Surgeries were performed by two surgeons utilizing the Smith-Robinson technique. The study included patients over 18 years of age, excluding those with a history of posterior cervical brace hardware or those undergoing corpectomy. Pseudarthrosis was determined using a dynamic mobility criterion: ≥ 4 mm of superjacent interspinous motion to validate functional cervical mobility, and ≥ 1 mm interspinous movement to indicate pseudarthrosis. Flexion and extension spinous movements were measured at 150% magnification on radiographs obtained between 6 months and 2 years post-surgery. Data analysis was conducted using univariate logistic regression. Results: The study included 100 patients (57 male) who underwent single and multilevel ACDF, totaling 214 individual levels. The fused group comprised 118 levels (55.14%), while pseudarthrosis occurred in 96 levels (44.56%). Six different bone matrix categories were used: i-Factor (154 levels), Propel Dense Bone Matrix (DBM) (2 levels), OsteoStrand Plus Fiber (46 levels), Grafton DBM (5 levels), NovaBone IRM Putty (2 levels), and Osteocel (5 levels). A lower level of upper instrumented vertebra (UIV) was increasingly associated with pseudarthrosis, with UIV of C6 and C7 showing significant association (p < 0.001). The use of i-Factor interbody material was associated with pseudarthrosis (p = 0.0368, OR = 1.61) when compared to all other bone grafts. Osteocel and Osteoprandplus Fiber showed borderline significance at p = 0.057 and p = 0.079, respectively. 47.4% of levels with i-Factor were consistent with pseudarthrosis compared to 38.3% of all other interbody composite materials (p > 0.05). Conclusion: This study suggests that the use of i-Factor significantly increases the likelihood of pseudarthrosis in ACDF procedures. Additionally, a higher rate of pseudarthrosis was observed at lower levels of operation. Based on these findings, the use of alternative interbody bone materials may be advisable to achieve proper fusion in ACDF procedures. Mary Kate Skalitzky 1 , Jared Hill 1 , Natalie Glass 1 , Yumeng Gao 1 , Catherine Olinger 1 1 University of Iowa, Iowa City, United States Introduction: As the rates of spinal fusion procedures increase across the world, there is continued need to ensure adequate fusion while preventing nonunion and pseudoarthrosis (1). Historically, autologous iliac crest bone graft was utilized to promote bony fusion (1, 2). However, associated risks and morbidity from autologous harvest has led to interest in alternative grafting materials. One such material is NanoBone. NanoBone is a synthetic bone graft composed of hydroxyapatite crystals in silica gel that per the developer, eliminates the need for autologous bone grafting. The aim of this study was to characterize utilization of NanoBone in posterior spinal fusion procedures at a single tertiary referral center. Materials and Methods: Patients who underwent posterior spinal fusions were evaluated from March 2018 through August 2022 via retrospective chart review. Patients were identified utilizing relevant CPT codes. The doses and counts of NanoBone implants for each procedure were collected. Autograft, allograft, and other bone graft alternatives were also recorded. Association rule mining was then conducted to explore common combinations of these fusion materials. Results: A total of 416 implant cases contributed by 397 patients, with a median age of 61.3 (51.8 - 69.5) years. The median BMI was 30.4 (26.5 - 34.7) kg/m 2 . Among them, 81.0% had procedures involving fewer than 3 spine levels, and 80.3% were primary cases rather than revisions. The following three findings occurred with 100% confidence among the sample group. (1) Whenever Allopac 25 cc and Graft Bone Infuse Kit are used together, NanoBone QD 5.0 mL is also provided. (2) Progenix Putty 5 cc always precedes Allopac 25 cc. (3) NanoBone QD 5.0 mL and NanoBone Putty 5.0 always precedes Allopac 25 cc. Conclusion: These key associations provide insight into the surgical trends in use of NanoBone as well as its benefits to patients in post-operative fusion. As interest grows in the field of synthetic allograft use for spinal fusion, NanoBone has proven to be a viable alternative to autograph. While NanoBone is a surgically viable alternative, one barrier to its implementation can be a lack of understanding in NanoBone dosing and combinations with other graft material. The present study evaluates trends in NanoBone use to equip surgeons with a better understanding of how NanoBone is used in the operating room. References 1. Reisener MJ, Pumberger M, Shue J, Girardi FP, Hughes AP. Trends in lumbar spinal fusion-a literature review. J Spine Surg . 2020;6(4):752-761. doi:10.21037/jss-20-492 2. Brodano GB, Lupidi F, Tardivo V, Bruzzo M, Verlicchi A, Zanotti B. Critical Evaluation of the Scientific Literature Concerning Bone Graft Alternatives in Spinal Surgery and Focus on Bioceramics. Surg Technol Int. 2022 Jun 23;41:sti41/1582. doi: 10.52198/22.STI.41.NS1582. Epub ahead of print. PMID: 35738571. Benjamin Jacobs 1 , Sai Krishna 2 , Hanny Anwar 1 1 Royal National Orthopaedic Hospital, Paediatric, London, United Kingdom , 2 Royal National Orthopaedic Hospital, Orthopaedic, London, United Kingdom Introduction: Aneurysmal Bone Cysts (ABC) are benign but destructive tumours containing osteoclast-like multinucleated giant cells with high RANK receptor expression. Denosumab is a biologic drug which blocks osteoclast maturation by binding to the Receptor Activator of Nuclear Kappa-B (RANK) ligand, an essential factor initiating bone turnover. Denosumab has therefore been used to treat ABC tumours which are not amenable to surgical excision. However, Denosumab use in patients younger than 18 years has been restricted due to the risk of severe rebound hypercalcaemia. We therefore used Zoledronate to stabilise calcium metabolism before, during and after Denosumab treatment. Material and Methods: Five patients (aged 8 to 17 years) presented with ABC lesions in the spine (2 cervical, 3 sacral) that were not amenable to surgery. All diagnoses were confirmed by our multidisciplinary team with clinical and radiological examination in all cases, and histology in 3 patients. Denosumab was given in 60mg subcutaneous injections monthly, with Zoledronate 0.05mg/kg given intravenously before the first Denosumab dose, 6-monthly during Denosumab treatment with one more Zoledronate infusion after the last Denosumab dose. Calcium metabolism was monitored closely with monthly measurement of blood and urine calcium as well as blood bone profile including Vitamin D and Parathyroid Hormone. The ABC tumours were monitored clinically and radiologically including Xray, CT and especially MRI scans. Results: All 5 patients improved with treatment. The first patient presented at 8 years of age in 2018 with severe neck pain and was found to have a large ABC tumour in the C3 vertebra. He improved steadily with Denosumab treatment and became asymptomatic. Radiological response was demonstrated with mineralisation on xray and reduction in tumour fluid levels on serial MRI scans. Treatment was stopped after 18 months but neck pain returned a year later. MRI showed regrowth of the ABC so treatment was given for a further 15 months. That second course of Denosumab was stopped more than 2 years ago and he is asymptomatic with good MRI response since. The other cervical spine patient presented at 14 years of age with spinal cord compression due to a large cystic tumour in the C5 vertebra. Biopsy and drainage of fluid from the cyst resulted in improvement in the symptoms of cord compression and histology confirmed the diagnosis of ABC with USP6 mutation. Zoledronate and Denosumab treatment led to continuing improvement in her symptoms and with reduction of fluid levels, tumour volume and mineralisation on follow-up imaging. The tumour was initially inoperable but after 4 months of Denosumab, a partial surgical excision was successfully performed. Denosumab was given for a further 4 months, followed by another Zoledronate infusion. She will require careful follow up to check for recurrence. The 3 patients with sacral lesions presented at 14, 15 and 17 years of age, all in severe pain. Two were being treated with opiates. All responded rapidly to Zoledronate and Denosumab treatment. One stopped treatment after 12 months and remains well 2 years alter. Another elected to have sclerotherapy treatment and improved continuously. She is now asymptomatic and no further treatment is planned. The third patient is improving continuously but still has foot drop due to sciatic nerve compression and so is continuing treatment. Conclusion: Denosumab in combination with Zoledronate is rapidly effective in relieving symptoms of ABC tumours in the spine. In some cases this alone has been sufficient treatment, in others it has allowed surgery and sclerotherapy to be performed safely. Long-term follow up is required though to detect ABC tumour recurrence, or side-effects of this novel treatment. Daryll Dykes 1 , Jill Ruppenkamp 1 , Katherine Corso 1 , Caroline Smith 1 , Michelle Costa 1 1 Johnson & Johnson, Raynham, United States Introduction: Novel graft materials to enhance bone growth in spinal surgery are continuously developed. Evaluating the effectiveness of these grafts is challenging due to potential confounding by indication with novel and more expensive grafts used in more challenging patients. Our study evaluated twelve-month outcomes in patients undergoing lumbar spinal fusion, based on graft material. Material and Methods: Patients undergoing lumbar fusion surgery in the Premier Healthcare Database from October 2015 to December 2022 were identified. Use of bioactive glass (“bioglass”) and/or bone morphogenetic protein-2 based graft materials (BMP) were identified from chargemaster entries. Outcomes included pseudarthrosis and infection twelve months post-index. Variables included patient, provider and surgery characteristics. Descriptive statistics were performed on all variables and outcomes. Adjusted rates of infection and pseudarthrosis were estimated using Poisson regression. Hospital costs were adjusted to 2022 inflation and index and twelve-month costs were estimated using generalized linear models. Results: 1,197 patients with bioglass graft and 72,204 with BMP were included in the analysis, with average age 62 in both groups, 17% of bioglass and 15% of BMP patients ≥ 75. In both groups, ∼ 90% were elective and 94% were treated in the inpatient setting. Patients with three or more comorbidities represented 40% of the bioglass and 34% of the BMP cohorts. Obesity and complicated diabetes were observed in 24% and 9% patients in both groups, respectively. At twelve months post-index, the pseudarthrosis rate was 1.6% (95% confidence interval (CI): 0.9%-2.3%)) in the bioglass group and 1.5% (95%CI: 1.4%-1.6%) in the BMP group. Index procedural costs averaged $44,815 (SD: 30,980) for bioglass and $47,227 (SD: 31,547) for BMP, and post-index twelve-month costs averaged $13,557 (SD: $28,919) for bioglass and $15,078 (SD: $37,396) for BMP groups. Conclusion: When used for lumbar spinal fusion procedures, the bioglass graft material resulted in twelve-month pseudarthrosis rates below 2%. Shahidul Islam 1,2 , Merina Tanzil 2 1 Ad-din Women's Medical College, Orthopedics and Spine Surgery, Dhaka, Bangladesh , 2 Barak PRP Medical Centre, Orthopedics and Spine Surgery, Dhaka, Bangladesh Introduction: Prolapsed intervertebral disc (PID) is a common cause of low back pain, back pain, neck pain and radiculopathy, which significantly affect quality of life. Traditional treatments include conservative treatment, physiotherapy, epidural steroid injection and surgery. Recently, platelet rich plasma (PRP) has emerged as a potential therapeutic option due to its regenerative property. This study aims to evaluate the efficacy and safety of epidural PRP injections in patients with prolapsed intervertebral discs, degenerative disc disease and spinal arthropathy, regarding pain relief, functional improvement, and reduction of the size of herniated disc in some cases. Materials and Method: 2000 patients with symptomatic prolapsed intervertebral disc were selected. Diagnosis was confirmed by MRI. 20 ml autologous PRP was injected in epidural area of the affected disc level. Total 3 doses were given, in 1 month interval. Clinical outcomes were assessed using the Visual Analog Scale (VAS) for pain. Repeat MRI were done after completion of treatment in some cases. Results: Patients receiving epidural PRP showed significant improvement in functionality and VAS score. Post treatment MRI in some cases showed a reduction in herniated disc size. Conclusion: Epidural autologous PRP injections appear to be a safe and effective treatment for a range of spinal disorders, providing significant pain relief and functional improvement. This biologic therapy could be a great alternative of invasive treatments, with the capability of tissue healing and regeneration. Further studies with longer-term follow-up are recommended. Jose Juan Parra Soto 1 , Ramiro Ramirez Gutierrez 1 1 Universidad de Monterrey, Cirugia de Columna, Monterrey, Mexico Introduction: The herniated disc occurs when the nucleus pulposus pushes through the fibrous ring, a thick ring of collagen that surrounds the nucleus pulposus. The first-line treatment is conservative management. Other therapeutic options have been explored, with infiltration of platelet-rich plasma (PRP) being a field of study for application in various spinal pathologies. Material and Methods: Retrospective, cross-sectional, observational study. We present the experience in treating herniated discs in 32 patients after the application of epidural platelet-rich plasma, evaluating changes in pain with VAS scale and function with ODI. Patients with low back pain for more than 4 weeks, patients who did not improve with conservative treatment, with a Visual Analog Scale > 5, and patients with no history of lumbar surgery with lumbar instrumentation were included. Results: 32 patients were included, and the demographic and clinical data were as follows; mean age was 42.25 years (SD 11.65). The intensity of pain in preoperative VAS showed a mean of 7.56 (SD 1.076) and postoperative pain at 6 weeks with 4.5 (SD 2.079) with a p = 0.006 and at 12 months with 1.59 (SD 0.615) with a p = 0.086. On the functional scale of preoperative ODI a mean of 45.16 (SD 10.702) and postoperative at 6 weeks a mean of 25.81 (SD 11.577) was found with a p = 0.005 and at 12 months with 8.78 (SD 4.133) of p = 0.000. No complications were found in 93.8% of the treated patients. Conclusion: Platelet-rich plasma treatment with transforaminal infiltration for patients diagnosed with lumbar intervertebral disc herniation offers functional and analgesic improvement. Keywords: disc herniation, Epidural infiltration, Platelet-rich plasma, disability, pain. Ramiro Ramirez Gutierrez 1 , Jose Juan Parra Soto 1 1 Universidad de Monterrey, Cirugia de Columna, Monterrey, Mexico Introduction: Lumbar discogenic pain is a common cause in primary care consultations and represents one of the main reasons for absenteeism and/or work disability, leading to an increase in public health costs. Currently, therapy with platelet-rich plasma (PRP) has been proposed as a regenerating treatment for the intervertebral disc based on its anti-inflammatory and repair properties. Material and Methods: A retrospective, observational, analytical, and cross-sectional study with a sample of 26 patients aged between 18 and 80 years treated with a percutaneous intradiscal approach involving the injection of platelet-rich plasma in patients diagnosed with lumbar degenerative disc disease, over a period of one year. An analysis is conducted with comparisons of means for related groups using the Student’s t-test with a 95% confidence interval, using the VAS (Visual Analog Scale for Pain) and ODI (Oswestry Disability Index). Only patients with discogenic pain without radiculopathies, who do not improve with conservative treatment, were included. Results: A total of 26 patients were included, with the following demographic and clinical data; the average age was 46.92 years (SD 15.45). The pre-surgical pain intensity on the Visual Analog Scale (VAS) showed a mean of 7.46 (SD 1.174) and post-surgical at 6 weeks with 4.96 (SD 1.755) p = 0.019, and at 12 months with 2.04 (SD 0.824) p = 0.026. In the functional scale of the Oswestry Disability Index (ODI), the pre-surgical mean was 50.04 (SD 10.761), and post-surgical at 6 weeks with a mean of 34.77 (SD 9.501) p = 0.037 and at 12 months with 14.85 (SD 6.649) p = 0.027. 76.9% of patients continued with conservative treatment due to improvement. Conclusion: In our study, we report clinical improvement at 12 months and no complications from the treatment with the percutaneous intradiscal PRP approach, suggesting it could be an alternative treatment aimed at clinical improvement and restoring function. However, a greater number of clinical trials with a larger number of patients, a control group, and longer follow-up time need to be conducted. Keywords: Degenerative disc disease, intradiscal injections, discogenic low back pain, platelet-rich plasma Jose Juan Parra Soto 1 , Ramiro Ramirez Gutierrez 1 1 Universidad de Monterrey, Cirugia de Columna, Monterrey, Mexico Introduction: Degenerative disc disease is a multifactorial condition characterized by chronic pain and symptoms of refractory pain related to degenerative changes in the intervertebral disc, which primarily causes biomechanical instability and inflammation. Currently, among the orthobiological treatments for degenerative disc disease, platelet-rich plasma, microfragmented fat, among others, have been proposed. Therapy with mesenchymal cells obtained through bone marrow aspirate concentrate (BMAC) has been proposed as a regenerating treatment for the intervertebral disc based on its anti-inflammatory and reparative properties. Material and Methods: This is a multicenter, retrospective, observational, analytical, and cross-sectional study with a sample of 35 patients aged between 18 and 80 years treated with a percutaneous intradiscal approach using bone marrow aspirate concentrate in patients diagnosed with lumbar degenerative disc disease over the course of one year. An analysis was conducted with comparisons of means for related groups using the Student's t-test with a 95% confidence interval, using the VAS (Visual Analog Scale for Pain) and ODI (Oswestry Disability Index). Only patients with discogenic pain without radiculopathies, who did not improve with conservative treatment, were included. Results: A total of 35 patients were included, with the following demographic and clinical data: average age of 46.92 years (SD 15.45). The pre-surgical pain intensity on the VAS showed a mean of 7.46 (SD 1.174) and post-surgical pain at 6 weeks was 4.96 (SD 1.755) with a p = 0.019, and at 12 months it was 2.04 (SD 0.824) with a p = 0.026. In the functional scale of ODI, the pre-surgical mean was 50.04 (SD 10.761) and post-surgical at 6 weeks showed a mean of 34.77 (SD 9.501) with a p = 0.037, and at 12 months it was 14.85 (SD 6.649) with a p = 0.027. There was a continuation without surgical treatment in 76.9% of the treated patients who showed improvement. Conclusion: In this study, clinical improvement of pain and function was identified at 12 months without complications from the BMA injection via percutaneous intradiscal approach, which could serve as an alternative treatment aimed at clinical improvement and enhancing function. However, a greater number of clinical trials should be conducted that include a larger population, follow-up imaging studies, and a longer follow-up duration. Hasan Ahmad 1 , Daksh Chauhan 1 , Omkar Anaspure 1 , Harmon Khela 1 , Robert Subtirelu 1 , Ryan Turlip 1 , Kevin Bryan 1 , Yohannes Ghenbot 1 , Connor Wathen 1 , Jang Yoon 1 , Prabaha Sikder 1 1 University of Pennsylvania Perelman School of Medicine, Philadelphia, United States Introduction: Polyetheretherketone (PEEK) cages, commonly used for spinal fusion, are bioinert and have decreased osseointegration, decreasing implant stability. We have developed an innovative composite material, termed Bio-PEEK, and employed Fused Filament Fabrication (FFF), a cutting-edge 3D-printing technology, to manufacture patient-specific implants (PSIs). These Bio-PEEK PSIs are designed to provide improved primary stability, negate the need for pre-implant bone grafting, and enhance tissue preservation around the implant site. Objective: In this study, we rigorously evaluate the mechanical performance of these Bio-PEEK cages, specifically focusing on their durability and load-bearing capacity. Methods: The strength of the cages was tested using load and stiffness analysis. The cages were incubated in Simulated Body Fluid (SBF) for 60 days. The mechanical properties of Bio-PEEK IBF cages were evaluated using tensile tests, compression tests, and three-point bending tests. Inductively coupled plasma (ICP) analysis was utilized to determine ion release. The results were compared to those of pure PEEK and other commonly used spinal fusion cages to determine the mechanical superiority of the Bio-PEEK IBF cages. Results: Load and stiffness analysis indicated that the cages could bear a maximum load of 5280 N with a stiffness of 6339 N/mm. After incubating the Bio-PEEK cage in SBF, the cage exhibited a load-bearing capacity of 5100 N and stiffness of 4463 N/mm, indicating no strength reduction. ICP analysis confirmed that the cages exhibit sustained ion release over 60 days, confirming that the cages exhibit release kinetics suitable for antibacterial efficacy and biocompatibility. Conclusions: The findings from our study highlight the long-term durability and consistent ion release kinetics of 3D-printed Bio-PEEK fusion cages. Through rigorous load and stiffness analysis, the cages have shown the capacity to withstand substantial loads, maintaining their structural integrity over time. This durability, combined with the sustained ion release, underscores the potential of Bio-PEEK in the realm of spinal fusion surgery. The results point towards Bio-PEEK's applicability as a platform technology, opening avenues for the development of versatile and multi-functional implants. These implants could offer enhanced clinical value, providing a reliable and effective solution for spinal fusion procedures. The study’s outcomes suggest that Bio-PEEK could play a pivotal role in advancing spinal implant technology, offering an alternative that marries mechanical strength with biological functionality, essential for successful spinal fusion surgeries. Elyette Lugo 1 , Branden Lee 2 , Victor Cardona-Perez 1 , Ahmed Sulieman 1 , Amit Jain 1 1 Johns Hopkins, Orthopaedic Surgery, Baltimore, United States , 2 Johns Hopkins University, Baltimore, United States Introduction: Health literacy is increasingly recognized as a key factor in patient outcomes across medical fields. In most specialties, health literacy is well-studied, with globally accepted questionnaires/methods for assessment, though there is still variability in whether it significantly impacts outcomes. In spine surgery, where complex decisions about surgery and postoperative care are common, patients with higher health literacy are better equipped to engage in shared decision-making, treatment compliance, and achieve better outcomes. Sociodemographic factors such as race, education, and socioeconomic status further affect health literacy. Despite its importance, there is limited research specifically addressing health literacy in spine surgery, unlike other fields where it is extensively studied. We aim to bridge that gap by examining how health literacy affects patient decision-making and surgical comprehension in spine surgery. Material and Methods: For this scoping review, we conducted a comprehensive search of peer-reviewed articles in Cochrane, Embase, and PubMed on August 2024, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two authors independently screened abstracts and full texts, resolving discrepancies through discussion or, when necessary, by consulting a third author for consensus. We included full-text studies that assessed health literacy, in addition to its impact on patient outcomes in individuals with spinal conditions. No restrictions were applied based on geographical location or language. Additionally, we evaluated factors influencing health literacy, disease knowledge, or awareness among patients with spinal conditions. Study quality was assessed using the Mixed Methods Appraisal Tool (MMAT). Results: We included 11 studies examining health literacy in spine-related orthopedic conditions, with a total of 4,139 patients. Most studies employed quantitative methods and cross-sectional designs. The studies primarily focused on health literacy and its effect on decision-making, patient-reported outcomes, health-related quality of life, and comprehension of surgical procedures. Of the 11 studies, 10 concluded that health literacy significantly impacts participation in decision-making, self-reported health, surgical comprehension, and quality of life. One study, however, found no significant correlation between health literacy and decision-making preferences in orthopedic spine surgery patients. Various tools were used to assess health literacy, including the Newest Vital Sign (NVS), Literacy in Musculoskeletal Problems (LiMP) survey, Control Preferences Scale (CPS), Brief Health Literacy Screening Tool (BRIEF), Rapid Estimation of Adult Literacy in Medicine-Short Form (REALM-SF), reflecting the variation of assessment tools in orthopedic spine settings. The studies highlighted key variables like race, education level, and socioeconomic status, which were consistently associated with lower health literacy. Conclusion: The findings underscore the significant role health literacy plays in influencing patient outcomes in orthopedic spine surgery, from decision-making to quality of life. However, the variability in assessment tools across studies highlights the need for globally accepted, standardized methods to assess health literacy. Amir Khadmy 1 , Sashin Sashin Ahuja 2 1 Beilinson Hospital, Orthopedic Department, Petach-Tikva, Israel , 2 Cardiff & Vale University Health Board, Spinal, Cardiff, United Kingdom Introduction: Endometriosis is a chronic inflammatory disease characterized by the presence of endometrial-like tissue outside the uterus, affecting approximately 10% of women of reproductive age. While often associated with pelvic pain and infertility, endometriosis can also manifest in extra-pelvic locations, including the spine. Vertebral-Spinal Endometriosis (VSE) is a rare but significant condition, presenting with a range of symptoms from asymptomatic findings to severe lumbosacral pain and radiculopathy. This study aims to synthesize existing evidence on VSE, focusing on its clinical presentation, diagnostic challenges, and treatment outcomes. Material and Methods: A systematic review was conducted in compliance with PRISMA guidelines, utilizing electronic databases (PubMed, Google Scholar, Cochrane Library) to identify relevant studies published up to 2023. Search terms included “endometriosis and spine,” “lumbar endometriosis,” and “sacral endometriosis.” Inclusion criteria encompassed peer-reviewed articles and case reports focused on clinical manifestations and treatment outcomes of VSE. Exclusion criteria ruled out studies centered solely on endometriosis infiltration in the lumbar plexus or peripheral nerves. Data extraction included patient demographics, clinical presentation, diagnostic methods, treatment modalities, and outcomes. Descriptive statistics and chi-square tests were employed to assess diagnostic and treatment associations. Results: The review included 18 case reports involving 18 patients diagnosed with VSE, with a mean age of 37.9 years. The most common symptoms were back pain (66.6%), radicular pain (60%), urinary symptoms (40%), and menstrual symptoms (40%). MRI was utilized in 86.66% of cases, while histological confirmation was performed in 73.33% of cases. The lumbar spine was the most frequently involved region (53.85%). Treatment methods included spinal decompression, hormonal therapy, or a combination of both. Post-treatment, 53.33% of patients reported symptom reduction, though chi-square analysis revealed no significant association between treatment methods and success (p-value = 1.00). Conclusion: Vertebral-Spinal Endometriosis presents unique diagnostic and therapeutic challenges due to its varied clinical manifestations and the lack of standardized diagnostic criteria. While MRI and histopathology remain crucial for diagnosis, they do not necessarily predict treatment outcomes. The current treatment strategies for VSE show limited efficacy in pain management, indicating a need for more targeted and multimodal approaches. Increased clinical awareness of VSE is essential, particularly in women with a history of endometriosis presenting with spinal pain. Further research is required to understand the underlying mechanisms, optimal management strategies, and long-term outcomes for VSE patients.

Oleksii Nekhlopochyn 1 , Anna Nikiforova 2 , Vadim Verbov 3 , Tetyana Yovenko 2 , Ievgen Cheshuk 3 1 Romodanov Neurosurgery Institute, Spine Neurosurgery, Kyiv, Ukraine , 2 Romodanov Neurosurgery Institute, Department of Medical Statistics, Kyiv, Ukraine , 3 Romodanov Neurosurgery Institute, Restorative Neurosurgery Department, Kyiv, Ukraine Introduction: Traumatic spinal cord injury (SCI) is a significant medical and social issue. Despite numerous studies, substantial success in reducing neurological consequences in such patients has not yet been achieved, and several aspects remain under-researched, particularly the response of the spinal cord to injury at different anatomical levels. The aim of the study is to analyze the influence of the anatomical level of injury, the patient's gender, and the mechanism of injury on the pattern of functional disorders in the acute period of spinal cord trauma using the largest publicly available database of patients with traumatic spinal cord injuries. Material and Methods: A statistical analysis of data from the National Spinal Cord Injury Model Systems Database (version 2021 ARPublic) was conducted. The analysis included 21,343 cases containing information on gender, age at the time of injury, circumstances of injury, the degree of neurological disorders at hospitalization, and the anatomical level of traumatic injury (with precision down to the spinal cord segment). Results: The data analysis revealed significant differences in the pattern of distribution of functional classes according to the American Spinal Injury Association (ASIA) scale depending on the anatomical level of SCI. For the cervical region, the distribution of frequencies for classes A, B, C, and D was: 43.06% (95% confidence interval (CI): 42.15-43.97%), 14.99% (95% CI: 14.35-15.66%), 16.17% (95% CI: 15.50-16.86%) and 25.78% (95% CI: 24.98-26.59%) respectively. For the thoracic region, the distribution of frequencies for classes A, B, C, and D was: 70.97% (95% CI: 69.94-71.97%), 10.27% (95% CI: 9.60-10.97%), 9.92% (95% CI: 9.26-10.61%) and 8.85% (95% CI: 8.23-9.51%). For the lumbar region, the distribution of frequencies for classes A, B, C, and D was: 21.29% (95% CI: 19.57-23.12%), 15.87% (95% CI: 14.35-17.52%), 24.43% (95% CI: 22.62-26.34%) and 38.40% (95% CI: 36.32-40.52%). Conclusion: The pattern of distribution of functional classes of neurological impairments significantly depends on the anatomical level of SCI. Thoracic segment injuries demonstrate the most clinically severe symptoms, whereas lumbar segment injuries are the least severe. The patient's gender does not have a statistically significant influence, while the circumstances of the injury correlate with the frequency of neurological impairments in cervical segments and do not affect this indicator in the lumbar region. Omkar Anaspure 1 , Anthony Baumann 2 , Andrew Fiorentino 2 , Katelyn Sidloski 2 , Jared Hinton 2 , Keegan Conry 3 , Gordon Preston 3 , Jacob Hoffman 3 1 Perelman School of Medicine, Philadelphia, United States , 2 College of Medicine, Northeast Ohio Medical University, Rootstown, United States , 3 Cleveland Clinic Akron General, Orthopedic Surgery, Cleveland, United States Introduction: Chemoprophylaxis for preventing VTE in spine surgery is debated due to effectiveness and safety concerns. Guidelines lack consensus on regimens and timing for spinal trauma. We examined chemoprophylaxis in spine trauma surgery to further guide surgeon decision-making. Methods: This systematic review and meta-analysis searched PubMed, CINAHL, MEDLINE, and Web of Science until March 14, 2024, for articles on chemoprophylaxis and spine trauma surgery. A random effects meta-analysis compared VTE events by chemoprophylaxis use and timing. Results: Fourteen observational studies (n = 13,754 patients; mean age: 41.74 ± 9.09 years; mean follow-up: 76.98 ± 213.45 days) were included. The total VTE prevalence was 6.28% (425/6771). VTE prevalence was 4.08% (143/3502) with chemoprophylaxis and 8.62% (282/3269) without. Meta-analysis showed no significant VTE difference between patients with (n = 516; 3.88%) and without chemoprophylaxis (n = 528; 5.68%) (p = 0.119, RR: 1.03; 95% CI: [0.99, 1.08]). No significant difference in postoperative bleeding was found between patients with (3.01% of 722 patients) and without chemoprophylaxis (5.74% of 766 patients) (p = 0.549, RR: 1.00; 95% CI: [0.99, 1.02]). Comparing early (n = 305; 5.90%) and late chemoprophylaxis (n = 271; 8.86%) showed no significant VTE difference (p = 0.289, RR: 1.06; 95% CI: [0.96, 1.14]). Postoperative bleeding was also not significantly different between early (n = 305; no complications) and late chemoprophylaxis (2.58%) (p = 0.328, RR: 1.14; 95% CI: [0.88, 1.48]). Conclusion: No significant association was found between chemoprophylaxis use or timing and VTE risk after spine trauma surgery, though this finding may be underpowered. Chemoprophylaxis did not appear to significantly increase postoperative bleeding. Subin Byanjankar 1 , Dipak Maharjan 1 , Haley Nadone 2 , Dheera Ananthakrishnan 3 , Hao-Hua Wu 2 1 Star Hospital, Orthopedics, Kathmandu, Nepal , 2 University of California, Irvine, Department of Orthopaedic Surgery, Global Spine Research Initiative, Orange, United States , 3 Emory University, Atlanta, United States Introduction: Spinal cord injury (SCI) is a debilitating condition with severe physical, psychological, and economic repercussions. Affecting over 15 million people globally, SCI is primarily caused by falls, traffic accidents, and violence, with varying incidence rates worldwide. South Asia, in particular, reports higher incidence rates compared to high-income regions. Although early rehabilitation has proven beneficial, there is a shortage of research on SCI rehabilitation outcomes in low- and middle-income countries such as Nepal. Material and Methods: This observational cohort study was conducted at Green Pastures Hospital and Rehabilitation Center (GPHRC) in Pokhara, Nepal, from May 2016 to September 2019. It included all SCI patients who were operatively treated and aged 17 and older admitted during this period, except those referred to other centers. Data collected encompassed demographics, injury mechanisms, injury levels, TLICS scores, neurological status, and timing metrics (from injury to admission, admission to surgery, and hospital stay). Outcome measures assessed were the Spinal Cord Independence Measure (SCIM), Modified Barthel Index (MBI), and American Spinal Injury Association (ASIA) scores at admission, discharge, and follow-up. Living conditions and accessibility were evaluated based on geographic and home location. Results: The study included 32 SCI patients (n = 32), with an average follow-up duration of 29.72 ± 11.3 months. The cohort comprised 17 males (53.12%) and 15 females (46.88%), with an average age of 34.94 years. Most patients (93.8%) lived in hilly regions, predominantly in rural areas (78.1%). The leading cause of injury was falls from heights (84.37%). The lumbar region was the most affected (65%), with burst fractures being the most common injury type (68%). On average, patients presented to the hospital 4.06 ± 4.19 days after injury, with a hospital stay of 26.75 ± 8.64 days and an average delay of 3.72 ± 2.69 days from admission to surgery. TLICS scores averaged 6.94 at admission, with longer injury-to-presentation times associated with higher TLICS scores (p = 0.014). Significant improvements were observed in SCIM and MBI scores from admission to discharge. Although the length of hospital stay correlated with SCIM improvement (p = 0.002), it did not significantly correlate with MBI improvement (p = 0.176). At final follow-up, SCIM and MBI scores further improved, averaging 31.47 (±3.14) and 95.19 (±8.47), respectively. ASIA grade recovery was significantly associated with SCIM and MBI improvements and patient age (p < 0.001). Accessibility findings indicated that 75% of patients could live independently, while 25% needed mobility or home access assistance. Conclusion: Effective rehabilitation of operatively managed SCI patients, particularly in low-resource settings like Nepal, requires a multidisciplinary approach. The study reveals a potentially higher prevalence of SCI among women in Nepal than previously reported and highlights that delays between injury and hospital admission correlate with more severe injury outcomes. Age significantly affects MBI improvements and ASIA grade recovery but does not significantly impact overall SCIM improvement. Harvinder Singh Chhabra 1 , Vandana Phadke 2 , Jitesh Manghwani 3 , El Sharkawi Mohammad 4 , Joseph Butler 5 , Lorin Benneker 6 , Emiliano Vialle 7 , Olesja Hazenbiller 8 , Richard Bransford 9 1 Sri Balaji Action Medical Institute, Spine and Rehab Department, Delhi, India , 2 Indian Spinal Injuries Centre, Clinical Research Department, Delhi, India , 3 Indian Spinal Injuries Centre, Department of Spine Services, Delhi, India , 4 Assiut University Medical School Assiut, Department of Orthopaedic and Trauma Surgery, Asyut, Egypt , 5 Mater Misericordiae University Hospital, National Spinal Injuries Unit, Dublin, Ireland , 6 Spine Unit, Sonnenh of Spital, Bern, Switzerland , 7 Cajuru Hospital, Catholic University of Paraná, Curitiba, Brazil , 8 AO Spine Foundation, AO Network Clinical Research, Davos, Switzerland , 9 Harborview Medical Center, Department of Orthopaedics & Sport Medicine, Seattle, United States Introduction: An analysis of the literature related to the assessment and management of spinal trauma was undertaken to allow the identification of top contributors, collaborations and research trends. Material and Methods: A search to identify original articles published in English between 2011 and 2020 was done using specific keywords in the Web of Science database. After screening, the top 300 most cited articles were analyzed using Biblioshiny R software. Results: The highest number of contributions were from the Thomas Jefferson University, USA, University of Toronto and University of British Columbia, Canada. The top 3 most prolific authors were Vaccaro AR, Arabi B, and Oner FC. The USA and Canada were among the top contributing countries; Switzerland and Brazil had most multiple country co-authored articles. The most relevant journals were the European Spine Journal, Spine and Spine Journal. Three of the 5 most cited articles were about classification systems of fractures. The keyword analysis included clusters for different spinal regions, spinal cord injury, classification agreement and reliability studies, imaging related studies, surgical techniques and outcomes. Conclusion: The study identified the most impactful authors and affiliations, and determined the journals where most impactful research is published in the field. Study also compared the productivity and collaborations across countries. The study highlighted the impact of development of new classification systems, and identified research trends including instrumentation, fixation and decompression techniques, epidemiology and recovery after spinal trauma. Edgar Valesin 1 , Guilherme Pajanoti 1 , Mariano Tamura 1 , Bruno Braga Roberto 1 , Mario Lenza 1 , Luciano Rodrigues 1 1 Hospital Israelita Albert Einstein, Sao Paulo, Brazil Introduction: Atraumatic sacral injury in postpartum women is rare and can be classified as a stress fracture when it affects a metabolically healthy patient during pregnancy and early lactation. Stress fractures typically occur in athletes or individuals who perform prolonged impact activities, while insufficiency fractures occur in patients with low bone mass, such as osteopenia or osteoporosis. The main symptom of a sacral stress fracture is low back pain radiating to the gluteal region, often underdiagnosed or diagnosed late. This report presents a postpartum patient with persistent low back pain, also in the late postoperative period of lumbar decompression, complicating the diagnosis. Material and Methods: A 46-year-old female patient, with no comorbidities, experienced severe low back pain a few days after her third normal delivery, without trauma. She had been under orthopedic follow-up for a previous lumbar disc herniation surgery performed 1 year and 1 month ago, with favorable recovery from low back pain and left-sided sciatica since the surgery. After completing 20 post-operative physical therapy sessions, the patient returned abroad, where she resides, maintaining a routine of light walking but no other physical activity. At this point, she was about 7 kg over her ideal weight. Approximately 3 months after spinal surgery, she became pregnant with her third child, gaining 12 kg during pregnancy, with normal routine tests and an uncomplicated natural delivery. Eight weeks postpartum, she reported persistent low back pain without radiation to the lower limbs or neurological changes. Physical examination revealed limited lumbar range of motion, negative Lasègue sign, and negative Gaenslen, Patrick-Fabere tests. MRI of the lumbosacral spine revealed a right sacral fracture. The treatment chosen was conservative, with rest and physical therapy, leading to gradual improvement in pain and functional limitations. Results: This report describes a 46-year-old postpartum patient who experienced atraumatic sacral fracture after her third delivery. She had a history of lumbar disc herniation surgery and gained 12 kg during pregnancy. Despite this rare condition, her clinical course was favorable with conservative treatment, including rest and physical therapy. Key questions remain: What is the prevalence of pregnancy-related sacral fractures? How do prior spinal surgeries impact this condition? What rehabilitation protocols are safest for postpartum patients, and when should MRI be used for persistent back pain in pregnancy or postpartum? Conclusion: Sacral stress fractures are a rare differential diagnosis but should be considered in cases of persistent low back and gluteal pain in late pregnancy or early postpartum. Although the exact pathophysiology is unclear, the combination of maternal metabolic demands and mechanical overload in the lumbosacral region likely contributes to this atraumatic injury. Patients with degenerative spinal diseases pose an even greater diagnostic challenge. Further studies are needed to clarify key risk factors and determine when imaging should be promptly used for low back pain in pregnancy and postpartum. Kazushi Takayama 1 , Teruo Kita 1 , Kohei Morita 1 , Hideki Sakanaka 1 1 Seikeikai Hospital, Dept. of Orthopaedic Surgery, Osaka, Japan Introduction: Fragility fractures of the pelvis (FFP) are an increasingly common injury seen in the elderly. The clinical symptoms of FFP are frequently vague and nonspecific. In addition, plain radiographs are usually insufficient for the diagnosis. Therefore, accurate diagnosis of FFP is often difficult and consequently delayed. The aim of this study was to determine the rate of occurrence of initially unrecognized or misdiagnosed FFP in our hospital and to evaluate the characteristic findings in those patients. Materials and Methods: This study was conducted with 409 patients consecutively, aged sixty years and older who were admitted with FFP at our hospital from January 2012 to February 2024. We evaluated the patients who were unrecognized or misdiagnosed at first visit or by previous doctors. Results: Fifty two patients (12.7%) were unrecognized or misdiagnosed initially. Forty six patients were female, and 6 were male. The mean age was 81.9 years (62-99 years). Sixteen patients had no traumatic events and 36 patients had a low-energy trauma, such as domestic falls. It took a mean period of 12.8 days (0-50) to diagnose. According to the Rommens classification, there were 13 type Ia, 2 type Ib, 22 type IIa, 14 type IIc, and 1 type IIIa fractures. Conservative treatment was carried out successfully in all patients. Conclusion: It is necessary to consider the possibility of FFP in cases of prolonged pain that can not be explained in elderly patients. Harvinder Singh Chhabra 1 , Vandana Phadke 2 , Jitesh Manghwani 3 , Marcel F. Dvorak 4 , Klaus Schnake 5 , Gregory Schroeder 6 , El Sharkawi Mohammad 7 , Richard Bransford 8 , Andrei Joaquim 9 , Olesja Hazenbiller 10 1 Sri Balaji Action Medical Institute, Delhi, India , 2 Indian Spinal Injuries Centre, Clinical Research Department, Delhi, India , 3 Indian Spinal Injuries Centre, Department of Spine Services, Delhi, India , 4 Vancouver General Hospital, Vancouver, Canada , 5 Malteser Waldkrankenhaus St. Marien, Erlangen, Germany , 6 Rothman Orthopaedic Institute, Thomas Jefferson University, Philadelphia, United Kingdom , 7 Assiut University Medical School Assiut, Asyut, Egypt , 8 Harborview Medical Center, University of Washington, Seattle, United States , 9 University of Campinas, Campinas, Brazil , 10 AO Spine Foundation, Davos, Switzerland Introduction: Analysis of literature on management and classification of osteoporotic vertebral compression fractures to identify the top contributing authors, countries, collaborators and the trends of research and how they differ on these aspects from traumatic vertebral fractures. Material and Methods: A search to identify original articles published in English between 2011 and 2020 was done using specific keywords in the Web of Science database. After screening, 442 articles met the criteria which were analyzed using Biblioshiny R software. Results: The top contributing authors were Yang HL, Wang H and Hao DJ. Amongst the universities, the major contributing ones were Soochow University, Guangzhou University of Chinese Medicine and University of Toronto. China, USA and South Korea were the top contributing countries. The maximum articles were published in Spine, Osteoporosis International and European Spine Journal. The most common articles were on comparisons between kyphoplasty and vertebroplasty, the associated complications and newer modalities of investigations of osteoporosis. Major work surrounds the keywords kyphoplasty and vertebroplasty which are significantly clustered as compared to others. Conclusion: The study identified the most prolific contributing authors (Yang HL, Wang H) and universities (Soochow University, Guangzhou University of Chinese Medicine), the journals where this work is considered more impactful (Spine, Osteoporosis International) and the top contributing countries (China, USA) and collaborations. This study showed that major work is regarding the cement augmentation techniques of kyphoplasty/ vertebroplasty and the attempts at establishing newer techniques of diagnosis of osteoporosis. Harvinder Singh Chhabra 1 , anuj mundra 1 , vandana phadke 2 , Marcel F. Dvorak 3 , Klaus Schnake 4 , Gregory Schroeder 5 , El Sharkawi Mohammad 6 , Richard Bransford 7 , Andrei Joaquim 8 , Olesja Hazenbiller 9 1 Sri Balaji Action Medical Institute, Spine and Rehab Department, Delhi, India , 2 Indian Spinal Injuries Centre, Clinical Research Department, Delhi, India , 3 Vancouver General Hospital, Vancouver, India , 4 Malteser Waldkrankenhaus St. Marien, Erlangen, Germany , 5 Rothman Orthopaedic Institute, Thomas Jefferson University, Philadelphia, United States , 6 Assiut University Medical School Assiut, Asyut, Egypt , 7 Harborview Medical Center, University of Washington, Seattle, India , 8 University of Campinas, Campinas, Brazil , 9 AO Spine Foundation, Davos, Switzerland Introduction: Spinal cord injuries (SCIs) present considerable challenges for individuals and healthcare systems worldwide, affecting motor, sensory, and autonomic functions. While a cure remains elusive, research into SCI rehabilitation and related complications has been extensive. This bibliometric analysis aims to map the scholarly landscape of SCI research, focusing on rehabilitation, complications, morbidity, mortality, aging, and outcomes. Material and Methods: Using the Clarivate Web of Science (WoS) database, we conducted a search on May 31, 2023, for articles published between 2011 and 2020. Keywords included “Spinal cord injury” combined with terms related to rehabilitation, complications, and outcomes. Original research papers and review articles in English were selected. We analyzed citation counts and used the Biblioshiny package in R software for bibliometric analysis, identifying top authors, journals, affiliations, and research trends. Results: A total of 2,645 articles were retrieved, from which the top 300 articles were selected. The majority were original research (87.8%), with a smaller proportion being review articles (11.9%). Notable authors included Fehlings MG, Curt A, and Post MWM. Prominent journals included Spinal Cord , Archives of Physical Medicine and Rehabilitation , and the Journal of Spinal Cord Medicine . The leading countries in contributions were the USA, Canada, and Australia. Analysis of keyword usage and citation patterns highlighted a focus on rehabilitation techniques and complications, with technological advancements such as robotics and exoskeletons emerging as significant areas of research. Conclusion: This bibliometric study provides insights into the current state of SCI research, highlighting influential authors, key journals, and emerging trends. The findings can guide future research and improve SCI rehabilitation strategies, ultimately enhancing patient care and quality of life for individuals with SCI. Carlos Alberto Carmona Lorduy 1 , Carlos Pacichana 1 , Gina Velásquez Solano 2 , Juan Pablo Mora Nova 3 1 Hospital Universitario del Caribe, Cartagena, Colombia , 2 Universidad de los Andes, Bogotá, Colombia , 3 Universidad del Rosario, Cartagena, Colombia Introduction: Chronic pain in the coccyx region (coccygodynia) is a rare condition with an unknown incidence, affecting mainly women between 20 and 50 years of age and associated with obesity as a risk factor. The most common cause is trauma as a result of a fall on the gluteus, repetitive microtrauma and give birth. In some cases, when pharmacological and interventional treatment fails, surgical intervention, such as total coccygectomy, is required as a last therapeutic option. Therefore, the aim of this study was to evaluate the improvement of pain and functionality by means of the Oswestry Disability Index (ODI) in patients with chronic coccygodynia who underwent surgery, with a 5-year follow-up. Material and Methods: A retrospective descriptive case series study was carried out including 10 patients with chronic coccygodynia who required total coccygectomy at the Medihelp services clinic in the city of Cartagena, Colombia, who were followed up for 5 years. Sociodemographic and clinical variables were recorded. Pain-related functionality was evaluated as primary outcome by means of the Oswestry Disability Scale, and as secondary outcomes: recovery time and presentation of complications such as infection, wound dehiscence and surgical re-intervention. Results: In this study, trauma was the main cause of chronic coccygodynia in 70% of the cases, followed by an idiopathic cause secondary to degenerative changes in 20%, and 10% caused by infection. The most frequent cause was dislocation fracture of the coccyx with unfavorable clinical evolution, which at initial screening went unnoticed or was managed conservatively. All patients required total coccygectomy with subperiosteal technique, chosen as the safest technique with the lowest probability of complications. In our series the most frequent complication was infection, which occurred in only 3 cases, the main causes being the proximity of the anus and perilesional microenvironment such as climate and humidity of the anatomical area; however, all cases progressed favorably without severe repercussions. At one year postoperatively, 90% of the cases reported a 50% improvement of the ODI score compared to the preoperative score. At 5 years of follow-up a 90% improvement of the ODI score was obtained, associated with a decrease in the use of analgesics, complete reincorporation to daily life activities and improvement of sexual activity. Conclusion: In order to improve pain and functionality in patients with chronic coccygodynia, total coccygectomy is an effective and low-cost technique that helps to improve the symptoms that affect the lives of patients suffering from this pathology by 90% as measured by the ODI. Additionally, in our case series, this technique presented a low percentage of complications, compared to the postoperative benefits such as return to daily life activities within an acceptable period. Finally, it is recommended in these patients during diagnosis to rule out tumor or infectious pathologies that require additional surgical techniques. Peter Wanyoike 1 1 Brain, Spine and Rehabilitation Hospital, Neurosurgery, Nairobi, Kenya Study design: Narrative review. Objective: The aim is to look at a holistic review of legal issues surrounding spine surgery, from the aspect of law and policy, ethical and medicolegal issues. Spine surgery is a complex and high-risk procedure presenting significant legal challenges in the medical field. This research delves into critical legal aspects surrounding spinal surgery, including legislative frameworks and policies that regulate the continuum of spine care and patient experience. It examines the legal standards of spine implant production and procurement, the ethical issues involved particularly around patient autonomy, informed consent, and decision-making in cases with uncertain outcomes. The study also addresses the standard of training required for spinal surgeons, emphasizing the need for specialized education to ensure patient safety and meet legal obligations. Moreover, it highlights the importance of certification for caregivers, ensuring that healthcare professionals involved in spinal surgery meet stringent competence standards. Lastly, the research discusses the legal and medical considerations for determining when a spine surgeon should cease performing spinal surgeries, balancing patient welfare and surgeon competence. By exploring these factors, this study aims to enhance legal and ethical frameworks that protect both patients and medical professionals in spinal surgery. Material and Methods: Multiple search engines including ASTM international, Pub Med, google scholar search tools, AO Global Spine education, and case reports. Results: There is no single or agreed general standard for spine Implats but ASTM international, a global innovations testing body has recommendations that are FDA approved. Informed consent is the hallmark of ethical medical practice globally and is the leading cause of legal recourse in medical malpractice claims. It is one of the four fundamental principles of ethics including beneficence, nonmaleficence and autonomy. There is also no single standard for training of spine surgeons, but various jurisdictions have different levels of medical and specialist training programs. AO has come with a diploma that may unify the training of future spine surgeons. The Various certifying bodies in different jurisdictions have the sole responsibility of recommending specialists for credentialing which then means that the laws of the land will apply. The issue of when to stop operating for surgeons remains a healthy debate with sometimes wisdom called into action and the question of “when is enough enough” starts to do the rounds. Conclusion: Understanding the legal issues surrounding spine care could help the spine care team of researchers, manufacturers, spine surgeons, distributers and after care teams avoid unnecessary malpractice claims. The four principles of ethics namely beneficence, nonmaleficence, autonomy and informed consent form the cornerstone in medical practice. Age and wisdom are a virtue which every surgeon plays will be the guiding principle in senior years. Luan Rocha 1 , Guilherme Laffitte 1 , André Luís Sebben 1 , Álynson Larocca Kulcheski 1 , Pedro Grein 1 , Felipe Nanni 1 , Joao Elias 1 , Xavier Soler I Graells 1 1 Complexo Hospitalar do Trabalhador, Curitiba, Paraná, Brazil, Spine Surgery, Curitiba, Brazil Introduction: Year after year, the number of gunshot-related spinal injuries has been increasing. Males account for the majority of cases, particularly in the second and third decades of life. The thoracic spine is the most commonly affected level, which is also the most susceptible to severe damage. Gunshot wounds account for almost 20% of spinal cord injuries, being the third leading cause of spinal cord injury in the civilian population. In addition to the imminent risk of death, subsequent injuries caused by trauma are highly debilitating. Surgical indications include partial neurological injury, fracture instability, projectile-related infectious injury, risk of migration, and cerebrospinal fluid fistula. It is worth noting the need to initiate antibiotic therapy as soon as possible and follow the principles of advanced trauma care. The objective of this study is to evaluate the experience in the care and management of gunshot wounds to the spine over 25 years in a trauma hospital. The challenges of these injuries vary from initial care to rehabilitation after the trauma. Materials and Methods: This is a retrospective cross-sectional study with data collected from medical records in the database of a trauma hospital in Brazil between 1999 and 2024. Excel software was used for analysis. The following variables were evaluated: age, gender, presence of neurological injury at admission, performance of arthrodesis, projectile removal, and affected spinal levels. The study followed the ethical principles of the Declaration of Helsinki. Results: The study found that 95% of the population was male, with an average age of 25.17 years among the 200 cases. The most affected level was the thoracic spine, with 37% of the cases, followed by the cervical spine, with 28%. Within the cervical spine lesions, 67% were subaxial, and 33% affected the C1 and C2 levels. Nearly three-quarters of the patients were admitted with neurological injury. A total of 44 patients had projectiles removed from the spinal canal, and 51 underwent arthrodesis, out of 83 who received surgical treatment. Conclusion: The care pattern for patients with gunshot wounds to the spine, over 25 years of experience, follows the principles established in the literature: prompt treatment, decompression, projectile removal, and arthrodesis when indicated. Thus, we can provide a better chance of motor recovery for incomplete spinal cord injuries and ensure proper fixation to prevent future spinal deformities. The results of our series converge with the epidemiological trauma patterns seen in studies from the literature. A thorough understanding of this type of trauma is essential for spine surgeons to offer the best possible treatment. Guilherme Laffitte 1 , Luan Rocha 1 , Álynson Larocca Kulcheski 1 , André Luís Sebben 1 , Pedro Grein 1 , Felipe Nanni 1 , Joao Elias 1 , Xavier Soler I Graells 1 1 Hospital do Trabalhador, Ortopedia e Traumatologia, Curitiba, Brazil Introduction: Spinal fractures represent a significant challenge in medical practice due to their potential severity and the impact they have on the quality of life of affected individuals. In a healthy spine, the muscles and ligaments play a crucial role in providing support, while the intervertebral discs function as cushions, absorbing compressive forces and supporting external loads. They also exhibit increased elasticity and plasticity, absorbing most of the impacts and reducing the risk of injury. When studying the population affected by ankylosing spinal conditions, such as ankylosing spondylitis (AS) or diffuse idiopathic skeletal hyperostosis (DISH), it is important to highlight that these cases tend to be more relevant. This is primarily due to the increased stiffness of the spine in these patients, making it more susceptible to severe injuries. Additionally, these individuals often already experience chronic back pain, which can lead to underdiagnosis when treated in emergency settings. The objective of this study is to present epidemiological data on patients with AO type B3 spinal fractures treated at a major trauma center in the southern region of the country. Additionally, we aim to compare the findings of this study with the existing literature to date. Material and Methods: A longitudinal, observational, and retrospective study evaluating a series of 20 cases with hyperextension spinal fractures from January 2013 to October 2021 in a trauma hospital database in Brazil. The variables analyzed included age, gender, affected spinal segment, mechanism of injury, type of treatment, neurological impairment before and after surgery, if done. Results: A total of 20 patients were evaluated, all presenting with anterior ligamentous injuries at a single level. The most prevalent level was cervical, with 13 cases, and the most common mechanism of injury was a same-level fall, observed in 11 cases, followed by motor vehicle accidents in 4 cases. Nine patients presented with neurological deficits after the trauma, and 8 of these patients continued to have some level of deficit despite the proposed treatment. Seventeen cases were treated surgically, while only 3 were managed conservatively due to absolute contraindications to surgical procedures. Conclusion: Hyperextension spinal fractures are rare injuries but have a high potential for permanent damage, often affecting a population that is challenging to diagnose due to comorbidities. Therefore, we recommend that all older patients with ankylosing spinal conditions be investigated for spinal injuries regardless of the presence or absence of localized complaints. If an injury is confirmed, surgical treatment should not be delayed unless there are clinical contraindications. Ashraf El Naga 1 , Monty Khela 1 , Obiajulu Agha 1 , Mark Xu 1 , David Gendelberg 1 1 University of California, San Francisco, California, United States Introduction: Posterior lumbopelvic fixation has largely been limited to lumbosacral dissociations with constructs often extending up to the lower lumbar spine. In cases where fusion is not indicated, this results in the need for hardware removal or expectant breakage of hardware. While iliosacral and trans-iliac trans-sacral screw fixation is the most common construct for more posterior pelvic ring injuries, several biomechanical studies have demonstrated that pedicle base spinopelvic fixation is a biomechanically more robust construct that can allow for early weight bearing. We propose that in select posterior pelvic ring injuries where the S1 pedicle remains intact, limiting the cranial extent of the construct to the upper sacral segment may offer a middle ground and avoid the need to span a mobile motion segment. Material and Methods: A retrospective review of all patients undergoing spinopelvic fixation at an academic level 1 trauma center was performed. For patients who underwent posterior spinopelvic fixation limited to the upper sacral segment, demographic data, fracture pattern, surgical fixation details, weight bearing restrictions, and follow-up duration, and re-operation were recorded. Results: 4 patients were identified, two of which were male and two were female. Two patients had U-type spinopelvic dissociations with minimal kyphosis and where the vertical limbs of the fracture were lateral to the S1 pedicles. Two patients had lateral compression type posterior pelvic ring injuries (LC2), one of which was unilateral and 1 was bilateral. All patients underwent percutaneous posterior S1 to ilium fixation. Average follow up was 141 days (range 4 to 244). Post-operatively, there were no weight-bearing restrictions for the pelvis specifically, but that 2 patients had separate lower extremity peri-articular fractures and therefore had their weight bearing limited to that side. There were no hardware failures or need for re-operation in all 4 patients. Conclusion: S1 to ilium posterior fixation may be a reasonable motion preserving option in select posterior pelvic ring injuries where a more robust construct than what is provided by traditional sacroiliac screw fixation. We limit the use of these constructs to injuries where the S1 pedicles remain intact. Such constructs obviate the need subsequent hardware removal and do not lead to the restrictions of lumbar motion compared to constructs that extend to the lower lumbar spine but still warrant further investigation with a greater number of patients. Sara Massuanganhe 1 , Enoque Langa 1 , Eduardo Cumbe 1 , Mircya Mandawa 1 , Missael Munguambe 1 , Mikail Salle 1 , Eva Timoteo 1 , Alcina Luis 1 1 Maputo Central Hospital, Surgery, Neurosurgery, Maputo, Mozambique Introduction: Spinal cord injury (SCI) is undeniably a public health issue, given the significant impact it has on patients' lifestyles. Traumatic spinal cord injury is considered a major cause of morbidity and mortality worldwide, affecting various age groups, but predominantly young working-age adults. It often occurs suddenly and unexpectedly, with a high potential to result in severe complications such as paraplegia and tetraplegia (Moraes et al., 2020). Road traffic accidents, falls, and self-inflicted violence are among the most common causes of SCI globally. In low-income countries such as Mozambique, where the national health system remains deficient in terms of infrastructure, human and material resources, as well as in the training of both professionals and the general population in basic principles for mobilizing patients at the scene of the accident, patients often suffer secondary injuries after the initial trauma during improper mobilization post-incident. Material and Methods: A retrospective cross-sectional analytical study was conducted with a sample of 75 participants admitted to the Neurosurgery Service at Maputo Central Hospital due to spinal cord trauma during the year 2023. Results: Of the 75 study participants, 75% were male, aged between 25 and 64 years. Regarding mechanisms of trauma, falls (49%) and road traffic accidents (40%) were the most prevalent causes. Upon admission, 25% of participants were classified as ASIA E, followed by ASIA A (25%). Approximately 67% had no associated trauma at the time of presentation. The cervical region was the most affected, with 49% of participants sustaining injuries in this area, and radiologically, 34% presented with type C injuries. Sixteen per cent of the participants underwent surgical intervention. Of the 75 participants, 95% were discharged, and during outpatient follow-up, 25% showed radiological improvement. Conclusion: Spinal cord injury in Mozambique carries a significant socioeconomic burden, both for patients and the healthcare system. The study’s results also indicate that the age range and gender distribution are consistent with those observed in studies from other parts of the world. However, the treatment outcomes remain suboptimal, as few patients have timely access to treatment due to long waiting times and subsequent patient dropout, as well as the lack of specialized equipment for certain procedures. Training both laypersons and healthcare professionals in the correct methods of patient mobilization and transportation from the trauma scene to the hospital remains a challenge. Nevertheless, positive results have been observed in those who do receive appropriate care. Ahmed Jahwari 1 1 Medical City for Military and Security Services, Muscat, Oman Introduction: Ante Grade Humeral Nailing (AGHN) with traditional positioning causes crowding at the patient’s head end, cramming for the surgeon and anesthetist, scarcity of space available for the scrub nurse and X-ray technician, and neurovascular risks while performing distal interlocking. Minimal literature is available regarding the optimal position and set up in the operating theatre (OT). The primary objective was to describe, how effective novel Jahwari’s position is by assessing the ergonomics for OT personnel, OT time, and radiation exposure. A secondary objective was to evaluate the safety of inserting distal interlocking screws. Surgical Technique: The head of the patient is placed away from the anaesthetist and their equipment, which were placed at the foot end of the patient. The patients were connected to the anaesthesia machine with a long airway extension, which was anchored to the table. The C arm machine was brought from the contralateral side and did not have to be moved. The scrub nurse and the surgeon were placed at the head end of the patient. Pregnant patients, those aged < 18 years, and those with open fractures were excluded from our study. A single consultant operated on all cases for standardization. OT time and radiation exposure were monitored. Conclusions: Inspired by our use of this position for cervical spine patients for more than a decade, Jahwari’s position and setup were innovated. This setup gives ample room for the anaesthetist at the foot end. The surgeon and assistants are free from cramming at the head end. Complementarily, it provides ample space for the X-ray technician and scrubs nurse. Keywords: Jahwari position, antegrade humeral nailing, modified lateral position. Learning point of the article: AGHN with traditional positioning causes scarcity of space available for the surgeon, assistant, scrub nurse, X-ray technician, risks while performing distal interlocking which are addressed by Novel room Set up called ‘Jahwari’s Position’. Jhonny Gomez 1 , Juan Rodriguez 1 1 Hospital Universitario del Vale, Universidad del Valle, Departamento de Ortopedia, Cali, Colombia Introduction: Spinopelvic dissociation is a rare injury, mainly associated with high-energy trauma, related to other types of injuries such as neurological and soft tissue compromise that can have a greater impact on the functional outcome of patients. The objective is to describe the clinical and demographic characteristics and surgical results in patients with spino-pelvic dissociation. Material and Methods: This is a retrospective case series where data were collected from a trauma center in Cali, Colombia during the period from December 2018 to december 2023. Results: 12 records were analyzed, 66.6% male patients and 33.3% female patients with a median age of 26 years (14-76 years). Two types of trauma mechanisms were identified, with a fall from a height being the main mechanism followed by traffic accidents. Half of the patients had neurological compromise and required surgical decompression with complete neurological recovery in one third of the patients. Surgical management showed good consolidation rates. The Wiltse para-median approach was proposed for surgical fixation with good results and no soft tissue complications compared to the conventional midline approach. There were no differences in functional outcomes between patients with or without neurological injury. Conclusion: Spinopelvic dissociation is a pathology that is related to high energy mechanisms; bone consolidation was observed in all cases operated on regardless of the type of fixation. The para-median Wiltse approach did not show soft tissue complications and although there is a high incidence of associated neurological injuries, their presence does not determine the functional results.

Hanna Salvotti 1 , Martin Proescholdt 1 , Nils-Ole Schmidt 1 , Sebastian Siller 1 1 University Hospital Regensburg, Department of Neurosurgery, Regensburg, Germany Introduction: Intradural spinal metastases are considered exceptionally rare. At present, limited information is available on incidence, surgical management and outcomes. Material and Methods: We conducted a retrospective patient chart review from 2002 to 2024 identifying all patients surgically treated for intradural spinal metastases. Clinical, surgical and survival data were collected and compared to literature data for patients surgically treated for extradural spinal metastases. Results: A total of 172 patients with spinal metastases were identified with 13 patients meeting inclusion criteria (7.6%). The mean age at diagnosis of intradural spinal metastases was 52 ± 22 years, with diverse primaries including lung (n = 3), breast (n = 2), sarcoma (n = 2) and six unique entities. Intradural spinal metastasis was diagnosed on average of 3.3 years after primary diagnosis. In total, we observed five (38%) intradural-extramedullary and eight (62%) intramedullary metastases, located in the cervical (38.5%), thoracic (46.1%) and lumbar spine (15.4%). The most common preoperative symptoms were pain, sensory changes and gait ataxia (each 76.9%). Gross-total resection was achieved in 54%, and local tumor control in 85%. Postoperatively, 92% exhibited clinical improvement or stability. Most frequent adjuvant treatment was radio- and/or chemotherapy in 85%. The average survival after operation for spinal intradural metastases was 5months, ranging from one month to 120 months. Location of the intradural metastasis in the cervical spine was associated with a significantly more favorable survival outcome (compared to thoracic/lumbar location, p = 0.02). Conclusion: Intradural location of spinal metastases is exceptionally rare (7.6%). Even so surgical resection is safe and effective for neurological improvement, survival appears lower compared to reported survival of extradural spinal metastases. Jessica Ryvlin 1 , Namal Seneviratne 2 , C. Rory Goodwin 3 , Raphaële Charest-Morin 4 , Michael Weber 5 , John Shin 6 , Anne Versteeg 7 , Mitchell Fourman 2 , Saikiran Murthy 2 , Reza Yassari 2 , Rafael De la Garza Ramos 2 1 University of Pittsburgh, Neurosurgery, Pittsburgh, United States , 2 Montefiore Einstein, New York, United States , 3 Duke University, Durham, United States , 4 University of British Columbia, Vancouver, Canada , 5 McGill University, Montreal, Canada , 6 University of Pennsylvania, Philadelphia, United States , 7 University of Toronto, Toronto, Canada Introduction: Understanding the role of hypoalbuminemia-related inflammation and malnutrition in patients with spinal metastases may guide medical optimization practices and oncologic treatment courses. As such, our objective was to conduct a scoping review of the literature to 1) identify albumin level cutoff values used to defined hypoalbuminemia in patients with metastatic spine disease, and to 2) describe the association between serum albumin level and operative/non-operative outcomes. Material and Methods: The PubMed/Medline, EMBASE, and Web of Science online databases were queried for articles up to December 2022 exploring the association between albumin and outcomes in metastatic spine disease patients. A narrative review was conducted utilizing variables such as study design, patient characteristics, serum albumin levels, treatments performed, and levels of evidence (LOE). Outcomes analyzed included survival/mortality, postoperative complications, ambulatory/functional status, readmission, length of hospital stay (LOS), discharge disposition, and blood loss. Results: A total of 38 studies were analyzed comprising a total of 21,401 patients. Most studies (92%; 35 of 38) were LOE III and 8% were LOE II (3 of 38). Out of all studies, 53% involved surgical intervention (21 of 38), followed by combined surgery and nonoperative management in 37% (14 of 38). Albumin was evaluated as a continuous variable in 18% of studies (7 of 38) and as a dichotomous variable in 76% of studies (29 of 38) with the following threshold values defining hypoalbuminemia: 3.0 g/dL (2 of 38 studies), 3.5 g/dL (n = 25), 3.7 g/dL (n = 2), 3.8 g/dL (n = 1), and 4.0 g/dL (n = 1). Primary outcomes evaluated were survival/mortality in 71% of studies (27 of 38), complications in 34% (n = 13), reoperation/readmission in 11% (n = 4), and LOS, ambulatory/functional status, discharge disposition, and blood loss in 5% each (n = 2 each). Out of 27 studies examining the association between hypoalbuminemia and survival/mortality, 74% (n = 20) found a significant association. An association between albumin levels and complications was only found in 54% (7 of 13) of studies. Conclusion: The findings of this study suggest that a threshold of 3.5 g/dL seems most appropriate to define hypoalbuminemia in patients with spinal metastases. However, evidence also supports a level-dependent effect. The most consistent significant association in the literature is between low albumin and post-treatment survival at both fixed and continuous time points. There is less evidence to support an association between hypoalbuminemia and other endpoints such as perioperative complications. Weronika Nocun 1 , Aidalena Chakar 1 , Rodrigo Muscogliati 1,2 , Mohammad Daher 1 , Elie Najjar 1 , Ahmed Hassan 1 , Nasir Quraishi 1 1 Queen's Medical Centre, Nottingham University Hospitals, Nottingham, United Kingdom , 2 Hull-York Medical School, Hull, United Kingdom Background: A solitary bone plasmacytoma (SBP) is a localised proliferation of plasma cells within a single bone site. Although SBP are rare, the spine is one of the more frequently affected locations. Currently, there is a scarcity of literature discussing solitary bone plasmacytoma of the spine (SBPS). Purpose: To evaluate the current literature on the clinical manifestations, locations, management and progression of SBPS. Methods: A systematic review of the English language literature using Pubmed, Embase and Cochrane and dating up until July 2024 was undertaken following Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Results: Out of the initial 503 articles, 17 were relevant. Regarding levels of evidence, 14 studies are level IV, one study is level III and two studies are Level II. Overall, 1,982 patients diagnosed with SBPS with a mean age of 55 (26 - 85) of which 36% were female were included. 88.3% of patients presented with pain, 78.6% presented with neurological symptoms out of which 40.5% included paraplegia, paraparesis or tetraparesis. 17.6% of patients presented with spinal deformity. At the time of diagnosis, 26.9% of the SBPS lesions were found in the cervical spine, 48.2% in the thoracic spine, 20.7% in the lumbar spine, and 4.7% in the sacrum. While only 35.4% of patients had an elevated paraprotein level, the rate of disease progression to multiple myeloma was 12.2%. The used treatments included radiotherapy, surgery, or a combined approach of radiotherapy and surgery. Conclusion: SBPS is a rare spine tumour that may present with severe neurological compromise. It most commonly affects the thoracic spine with a 12.2% chance of progression to Multiple Myeloma. Radiotherapy is the first line of treatment, but surgery may be needed in cases of neurological or structural compromise. Varun Agarwal 1 1 Rohilkhand Medical College and Hospital, Orthopedics, Bareilly, India Introduction: aneurysmal bone cyst in vertebrae is rare. They are expansile lesions may lead to compressive myelopathy. Involvement of posterior elements are rare. They are difficult to diagnose radiographically before biopsy and surgery. Material and Method: A 14-year-old male present to our institute with complain of mid back pain associated with motor weakness below L4 level with sensory deficit below L3 level with intact bowel and bladder. MRI scan showed Locally aggressive, expansile, lobulated extramedullary, intradural mass lesion with extradural extension and involvement of I/L pedicle, facet joint, lamina and spinous process. CT scan showed Ill-defined enhancing expansile lytic lesion involving D12 vertebral body and its posterior elements and pedicle of D11 vertebra showing multiple septations within with Air fluid level. Managed by minimally invasive robotic guided aneurysmal bone cyst embolization and curettage with decompression and posterior stabilization from D10-L2 level. Histopathological examination showed cystic areas rimmed by osteoclastic giant cells, reactive woven bone with fibroblast with focally blue metaplastic bone. Result: Post operative patient was able to walk with foot ankle orthosis bilaterally with support. In 2 months follow up motor power increased from grde0 to grade 5 from L3-S1 level. Conclusion: Management and fixation with help of robotic guidance is much more efficient as compared to conventional open techniques. It helps in precise screw placement. Less surgical dissection leading to reduced blood loss, less surgical time. Less post operative hospital stays and early mobilization. Federico Landriel 1 , Kevin White 2 , Alfredo Guiroy 3 , Alvaro Silva González 4 , Charles Carazzo 5 , Christiano Simões 6 , Gustavo Giraldo 7 , Juan P. Cabrera 8 , Marcelo Molina 4 , Marcelo Alejandro Valacco 9 , Nelson Astur 10 , William Teixeira 11 , Santiago Hem 1 1 Hospital Italiano de Buenos Aires, Spine Unit - Neurosurgery, Buenos Aires, Argentina , 2 ScienceRight, Statistics, Ontario, Canada , 3 Clinica de Cuyo, Neurosurgery, Mendoza, Argentina , 4 Clínica Alemana, Spine Unit - Orthopedics, Santiago de Chile, Chile , 5 Hospital São Vicente de Paula / Universidade de Passo Fundo, Brasil, Neurosurgery, Paso Fundo, Brazil , 6 Hospital Felício Rocho, Neurosurgery, Belo Horizonte, Brazil , 7 Hospital Pablo Tobón Uribe, Neurosurgery, Medellín, Colombia , 8 Hospital Clínico Regional de Concepción, Neurosurgery, Concepción, Chile , 9 Hospital Churruca, Spine Unit - Orthopedics, Buenos Aires, Argentina , 10 Hospital Israelita Albert Einstein, Spine Unit - Orthopedics, Sao Paulo, Brazil , 11 DWO Médicos Associados, Spine Unit - Orthopedics, Sao Paulo, Brazil Introduction: The Spinal Instability Neoplastic Score (SINS) classification system is a validated and the most widely accepted instrument for defining instability in vertebral metastasis (VM), in which lesions scoring between 7 and 12 are defined as indeterminate and the treatment is controversial. This study aimed to determine which variables more frequently are considered by spine surgeons for choosing between the conservative and the surgical treatment of VMs among patients with an indeterminate SINS. Material and Methods: A single-round online survey was conducted with 10 spine surgeons with expertise in the management of VMs from our AO Spine Region. In this survey, each surgeon independently reviewed demographic and cancer-related variables of 36 real-life cases of patients with vertebral metastases scored between 7 and 12 in the SINS. Bivariate and multivariate analyses were performed to identify significant SINS and non-SINS variables influencing the decision-making on surgical treatment. Results: The most commonly variables considered important were the SINS element “mechanical pain”, rated important for 44.4% of the cases, “lesion type” for 36.1%, and “degree of vertebral collapse” and the non-SINS factor “tumor histology” rated for 13.9% of cases. By far the factor most commonly rated unimportant was “posterior element compromise” (in 72.2% of cases). Conclusion: Surgeons relied on mechanical pain and type of metastatic lesion for treatment choices. Vertebral collapse, spinal malalignment, and mobility were less influential. Spinal mobility was a predictor of surgical versus non-surgical treatment. The only variables not identified either by surgeons themselves or as a predictor of surgery selection was the presence/degree of posterolateral/posterior element involvement. Keywords: SINS; Spinal instability; Spinal metastases; Spine; Spine tumor. Federico Landriel 1 , Kevin White 2 , Fernando Padilla Lichtenberger 1 , Alfredo Guiroy 3 , Alisson R. Teles 4 , Eduardo Laos 5 , Jerônimo Milano 6 , Marcelo Neto 7 , Nelson Astur 8 , Oscar González 9 , Ratko Yurac 10 , Rodolfo Paez 11 , William Teixeira 12 , Santiago Hem 1 1 Hospital Italiano de Buenos Aires, Spine Unit - Neurosurgery, Buenos Aires, Argentina , 2 ScienceRight, Ontario, Canada , 3 Clinica de Cuyo, Spine Unit - Neurosurgery, Mendoza, Argentina , 4 Hospital São José - Santa Casa de Porto Alegre, Spine Unit - Neurosurgery, Porto Alegre, Argentina , 5 Almenara Hospital, Neurosurgery, Lima, Peru , 6 Neurological Institute of Curitiba, Neurosurgery, Curitiba, Brazil , 7 Hospital Alemão Oswaldo Cruz, Orthopedics, Sao Paulo, Brazil , 8 Hospital Israelita Albert Einstein, Orthopedics, Sao Paulo, Brazil , 9 Complejo Asistencial Víctor Ríos Ruiz, Los Angeles, Chile , 10 Clínica Alemana, Orthopedics, Santiago de Chile, Chile , 11 Hospital Infantil Universitario de San José Bogotá, Orthopedics, Bogotá, Colombia , 12 DWO Médicos Associados, Orthopedics, Sao Paulo, Brazil Introduction: Combining surgery and radiotherapy is the gold standard in treating spinal metastasis when spinal stabilization or surgical decompression is required. However, determining the optimal timing for radiotherapy post-surgery is crucial to balance treatment efficacy and minimize wound complications. The study aimed to identify consensus and non-consensus areas among Latin American spinal surgeons regarding the use, timing, risks, and surgical approach to conventional radiotherapy following spinal surgery for metastatic spine disease, specifically focusing on the risk of radiotherapy-related wound complications. Material and Methods: A modified Delphi survey was conducted. The expert panel included active members of AOSpine Latin America with extensive experience in vertebral metastasis surgery. The surveys include thirty-seven statements covering areas of interest. Inter-expert consensus was considered weak (70-79.9%), moderate (80-89.9%) and strong (≥ 90%). Results: At least 70% consensus was reached on 32 of the 37 statements (86.5%). This included strong consensus on 10 statements, moderate on 13, and weaker on nine. There was high consensus on sutures and lower consensus on risk factors for radiation therapy (RT) delay. Experts reached strong agreement on the importance of poor nutrition as a risk factor for RT-related wound complications. Perception of wound risk was greater with a posterior midline approach compared to other approaches, and the highest perceived complication risks were for junctional locations and sacral spine. Conclusion: We report strong agreements among the experts on important issues such as waiting times and risk factors for radiation therapy. The findings underscore the significance of considering factors such as, spinal levels, surgical approaches, and sutures when making clinical decisions. Keywords: Radiotherapy timing, Wound complication, Wound dehiscence, Metastatic spine Delphi study. Petr Rehousek 1 , Mohsin Khan 1 , Simon Hughes 1 1 Royal Orthopaedic Hospital, Spinal Oncology, Birmingham Sarcoma Service, Birmingham, United Kingdom Introduction: A chordoma is a low-grade, slow-growing, but locally invasive and locally aggressive tumour. They arise from the remnants of the notochord and occur in the midline along the spinal axis from the clivus to the sacrum, anterior to the spinal cord. Evaluation of chordomas revolves around imaging and biopsy. Magnetic resonance imaging (MRI) best delineates the extent of a chordoma. Despite the low-grade status of chordomas, they have a high recurrence rate and significant mortality. Methods: The treatment which provides the longest survival is complete en bloc resection of the tumour with clean margins. Intratumoral resection and piecemeal resection may also provide a similar benefit if complete chordoma resection can be achieved without local seeding. Local debulking is sometimes advocated if complete resection is not technically feasible. Improvement in surgical techniques has widened the opportunities to provide effective treatment. However, the effects of adjuvant treatment options are still both unclear and controversial. Substantial progress has been made in the study of molecular-targeted therapy. Results: We provide a retrospective review of treating 260 chordomas (25% mobile spine and 75% sacrococcygeal) in an adult and paediatric population (mean age 61 years, range 5-94) referred to our institution spanning a 50 year period. This includes a detailed analysis of prognosis, survival, recurrence rates, and our experience with en-block resection followed by proton beam therapy. Alexandrina Nikova 1 , Tiffany Georgiou 2 , Vasilios Vafiadis 3 , Panayiotis Filias 4 , George Markogiannakis 4 1 Asclipieio Voula Hospital, Athens, Greece , 2 Agios Panteleimon Hospital Nikaias, Athens, Greece , 3 Agia Sofia Childrens’ Hospital, Athens, Greece , 4 Children’ Hospital Panayiotis and Aglaia Kyriakou, Athens, Greece Objective: Reiki is an alternative holistic therapy technique, used from the ancient times to remove energetic blockages, for relaxation and stress removal. Its utility in medicine is constantly increasing in various fields, but never in neurosurgery or spine surgery. Therefore, the preset study has the aim to present a case of reiki therapy used in spine surgery. Case Description: A 7-year boy was presented at the pediatric hospital in Athens with cervical pain. An MRI was obtained showing enlarged mass in the cervical spine from C3 to C7 vertebra. Surgery was planned, while the patient received two reiki therapies before and after surgery. The surgery went without any complications, or any blood transfusion, while the post operative white blood cells were in normal range (reiki reduces the stress syndrome of surgery). Postoperatively, the MRI showed complete resection. The patient was discharged in five days postoperatively. The histopathological report showed cervical pilocytic astrocytoma, and the patient was transferred to the oncological department for further management. Conclusion: Reiki therapy used in daily manner in spine surgery and neurosurgery could be not only helpful for complication management, but also very useful for stress syndrome management and faster healing process. Reiki itself has no complications and does not interfere with the traditional techniques in any way. Aman Singh 1 , Victor Gabriel El-Hajj 1 , Erik Edström 1 , Adrian Elmi Terander 1 1 Karolinska Institutet, Stockholm, Sweden Introduction: Spinal schwannomas are the second most common primary intradural spinal tumor. This study aimed to assess Health-related quality of life (HRQoL) and the frequency of return to work after surgical treatment of spinal schwannomas. Material and Methods: Patients operated for spinal schwannomas between 2006 and 2020 were identified in a previous study and those alive at follow-up (171 of 180) were asked to participate. HRQoL data was compared to a sample of the general populations. For that, the Stockholm Public Health Survey 2006, a cross-sectional survey of a representative sample of the general population was used. Results: Ninety-four (56%) responded and were included in this study. An analysis for any potential non-response bias was performed and showed no significant differences between the groups. HRQoL was equal between the spinal schwannoma sample and the general population sample in all but one dimension; men in the spinal schwannoma sample reported more of moderate problems in the usual activities dimension than the men in the general population (p = 0.020). In the schwannoma sample there were no significant differences between men and women in any of dimension, EQ-5D index or EQ VAS . Before surgery a total of 71 (76%) were working full time and after surgery almost all (94%) returned to work. Most of them within three months of surgery. Eighty-nine (95%) of the patients responded that they would accept the surgery for their spinal schwannoma if asked again today. Conclusion: Surgery for spinal schwannoma is safe and the results show a significant improvement in neurological function. HRQoL was equal between the spinal schwannoma sample and the general population. The spinal schwannoma sample reported a limited use of pain medication and patients working preoperatively generally returned to work. Based on the findings of this study, surgical treatment of spinal schwannomas is associated with good HRQoL and with a high frequency of return to work. Husain Shakil 1 , Ahmad Essa 2 , Armaan Malhotra 1 , Christopher Witiw 1,2 , Donald Redelmeier 3 , Jefferson Wilson 1,2 1 University of Toronto, Division of Neurosurgery, Department of Surgery, Toronto, Canada , 2 St. Michael's Hospital, Unity Health Toronto, Division of Neurosurgery, Department of Surgery, Toronto, Canada , 3 Institute of Health Policy Management and Evaluation, Toronto, Canada Introduction: In this meta-analysis and evidence appraisal, we compare minimally invasive surgery (MIS) to open surgery for treatment of metastatic spine tumors with respect to perioperative outcomes. Few studies have systemically assessed the body of evidence on this topic. Material and Methods: A systematic review of EMBASE and PUBMED from inception to December 2023 was performed to identify studies comparing MIS to open surgery for treatment of spine metastases. Nine outcomes were collected: estimated blood loss (EBL), operative time, hospital length of stay (LOS), risk of revision, risk of neurologic deterioration, likelihood of receiving post-operative radiation, time to radiation, time to chemotherapy, and treatment of pain measured through patient reported visual analogue scale (VAS). We used meta regression to estimate adjusted mean differences (aMD) and adjusted odds ratios (aOR) for outcomes. Certainty of evidence was appraised using the GRADE approach. Results: We identified 34 eligible studies including 1656 patients with spinal metastases, with 904 (54.6%) treated with MIS and 752 (45.4%) treated with open surgery. MIS was associated with significantly less blood loss (aMD -602 mL, 95% CI -1204 to -0.2 mL, I2 = 97%) with moderate certainty of evidence. MIS was found to be non-inferior with respect to operative time (aMD 2.6 mins, 95% CI -53.3 to 48.1 mins, I2 = 88%), risk of revision (aOR 0.9, 95% CI -0.8 to 1.1, I2 < 0.01), risk of neurologic deterioration (aOR 0.9, 95% CI 0.8 to 1.0, I2 < 0.01), likelihood of post-operative radiation (aOR 0.9, 95% CI 0.7 to 1.4, I2 < 0.01), and post-operative VAS (aMD -0.3, 95% CI -1.1 to 0.5, I2 = 52%) with low certainty of evidence. MIS was associated with significantly shorter time to chemotherapy (-0.9 MD, 95% CI -1.9 to -0.01, I2 = 22%), with very low certainty of evidence. Inferences for LOS and time to radiation were indeterminate, however, we found a trend toward earlier radiation with MIS, that was significant in the subgroup of patients treated with decompression and fusion. Conclusion: Among patients with metastatic spine disease, treatment with MIS compared to conventional open surgery was associated with reduced EBL, shorter time to chemotherapy, similar operative time, and similar reductions in post-operative pain. Future prospective research is very likely to improve our certainty in comparative estimates of perioperative outcomes. Husain Shakil 1 , Armaan Malhotra 1 , Ahmad Essa 2 , Arjun Sahgal 3 , Nicolas Dea 4 , Michael Fehlings 1 , Christopher Witiw 1 , Jefferson Wilson 1 1 University of Toronto, Division of Neurosurgery, Department of Surgery, Toronto, Canada , 2 Li Ka Shing Knowledge Institute, Toronto, Canada , 3 University of Toronto, Radiation Oncology, Toronto, Canada , 4 University of British Columbia, Division of Spine Surgery, Department of Surgery, Vancouver, Canada Introduction: Chordoma are rare malignant primary bony tumors, with a predilection to the spine and skull base. Given their rarity, there are limited studies evaluating trends in care, and epidemiology of these tumors. In this study, we aimed to estimate recent trends in the incidence, treatment patterns and overall survival for patients with chordoma. Material and Methods: We conducted a seventeen-year (2003-2019) population-based cohort study identifying all patients newly diagnosed with histologically proven chordoma and residing in Ontario, Canada. Our primary outcomes of interest were age standardized annual incidence, overall survival, and rates of radiation therapy, chemotherapy, and open surgical resection. Results: Two hundred and eight patients were diagnosed with chordoma over the study period. Ninety-seven patients had skull base chordoma, 37 had chordoma of the mobile spine, and 65 had a sacropelvic chordoma. One hundred thirty patients were treated with either open or endoscopic surgery, of which ninety-seven were also treated with some form of radiation therapy. Across the 17-year study period, the average annual age standardized incidence was 12.04 cases per 10 million (95% CI 9.31 to 14.78 cases per 10 million). We found no significant change in the annual incidence rate over the study period (AAPC 2.27, 95% CI -1.74 to 6.44, p = 0.25). The odds of having radiation or chemotherapy significantly increased by 8% per year (95% CI 1% to 16% per year, p = 0.036) over the study period. The odds of open surgical resection significantly decreased by 13% per year (95% CI 6 to 9%, p < 0.001). The odds of endoscopic surgery among patients with skull base chordoma increased by 38% per year (95% CI 22% - 60%, p < 0.001), while the odds of patients having biopsy alone did not change significantly over the study period (p = 0.945). After diagnosis of chordoma, the 5, 10, and 15-year overall survival were 0.75 (95% CI 0.69 to 0.81), 0.58 (95% CI 0.51 to 0.67), and 0.48 (95% CI 0.40 to 0.59), respectively. There was no significant association between hazard of death and year of diagnosis (p = 0.108), or anatomic location (p = 0.712, skull base vs mobile spine chordoma; p=0.518 skull base vs sacropelvic chordoma). Conclusion: Chordoma is a rare disease with no significant change in the average annual incidence rate between 2003 to 2019. There is a shift toward non-invasive modalities of treatment, particularly for skull base chordoma. Overall survival exceeds 10 years for many patients, with no change in the hazard of death across the study period. Diogo Rodrigues 1 , Sara Sequeira 2 , Filipa Adan e Silva 1 , Ana Lucinda Correia 1 , Diogo Catelas 1 , Filipa Cordeiro 1 , Ricardo Rodrigues-Pinto 1 1 ULS Santo António, Porto, Portugal , 2 ULS Lisboa Ocidental, Lisboa, Portugal Introduction: Aneurysmal bone cysts (ABCs) are uncommon, benign, fluid-filled lesions, most often encountered in children and adolescents. They may affect the spine, occasionally leading to neurological deficits even in the absence of spinal instability. Treatment strategies for these cases are challenging. We report a case showcasing the efficacy of achieving spinal cord decompression solely through selective arterial embolization. Material and Methods: We retrospectively report and analyze a case of a 16-year-old boy with symptomatic spinal cord compression due to ABC located in the T1 and T2 vertebrae (mJOA 13). He was treated by selective arterial embolization (SAE) using particles, with 3 procedures over the course of 4 months. His follow-up period is 2 years. Results: We observed a progressive volume reduction and ossification of the lesion, with widening of the spinal canal and resolution of the spinal cord compression symptoms. At 2-year follow-up, the patient remains asymptomatic, and has returned to his usual activities. Conclusion: Our report demonstrates that it is possible to achieve successful spinal cord decompression solely through SAE, offering a less invasive approach without the need for surgery. The use of SAE in this specific group of patients (symptomatic spinal cord compression without spinal deformity/instability), might be a safe and effective alternative to surgery. Anthony Baumann 1 , Robjert Trager 2 , John Strony 3 , Omkar Anaspure 4 , Aditya Muralidharan 5 , Tyler Sanda 6 , Jacob Hoffman 6 1 College of Medicine, Northeast Ohio Medical University, Rootstown, United States , 2 University Hospitals, Cleveland, Department of Rehabilitation Services, Cleveland, United States , 3 University Hospitals, Cleveland, Orthopedic Surgery, Cleveland, United States , 4 Perelman School of Medicine, Philadelphia, United States , 5 University of Michigan, Orthopedic Surgery, Ann Arbor, United States , 6 Cleveland Clinic Akron General, Orthopedic Surgery, Cleveland, United States Background: There is limited evidence regarding the effectiveness of chemoprophylactic anticoagulation for preventing venous thromboembolism (VTE) after spine surgery for spinal metastasis. We aim to test the hypothesis that early heparin administration (0-2 days after surgery) is associated with a significant decrease in the risk ratio of VTE through two weeks after spine arthrodesis for spinal metastasis compared to matched controls not receiving any anticoagulation. We secondarily explored the risk and cumulative incidence of VTE over two months, and risk of severe postoperative bleeding (SPOB). Methods: This retrospective cohort study used the United States TriNetX network to identify adults undergoing their first spinal arthrodesis surgery for spinal metastasis over the past 20 years and divided these patients into two cohorts according to the use of anticoagulation on the same date of surgery: a heparin cohort and a control cohort without anticoagulation. Patients were propensity matched according to key risk factors for VTE. Our primary outcome was the risk ratio (RR) with 95% confidence intervals (CI) of VTE through two weeks post-arthrodesis. We secondarily explored incidence and RR of VTE and SPOB through two months’ follow-up. Results: There were 847 patients per cohort after matching. There was no statistically significant difference in incidence of VTE in the heparin group compared to the no anticoagulation cohort through two-weeks’ (4.0% versus 2.7%; RR: 1.48; 95% CI: 0.88, 2.49; p = 0.1383) and two months’ follow-up (9.4% versus 7.9%; RR: 1.2; 95% CI: 0.88, 1.63; p = 0.2619). Furthermore, there was no statistically significant difference in incidence of SPOB in the heparin group compared to the no anticoagulation group at two-weeks’ (1.5% versus 1.7%; RR: 0.93; 95% CI: 0.44, 1.96; p = 0.8462) and two-months’ follow-up (2.8% versus 2.5%; RR: 1.1; 95% CI: 0.64, 2.04; p = 0.6504). Conclusion: Early heparin administration after spine fusion for spinal metastasis was not associated with a significant change in VTE or SPOB compared to matched controls without anticoagulation through two months following spinal fusion. Future studies should examine if other commonly utilized anticoagulants, such as enoxaparin, are associated with a lower risk of VTE after spine fusion for spinal metastasis. Although retrospective in nature, this study represents the largest cohort study to date on this topic. Aditya Swaminathan 1 , Miki Shikanai 1 , Ilijana Sumonja Zisakis 2 , Siu Li Boo 3 , Melvin Grainger 2 , Huma Haseeb 3 , Thomas Land 2 , Jonathan Shadwell 3 , Sophie Walters 3 , Hussein Shoukry 4 , Wai Soon 2 , Marcin Czyz 2 1 University of Birmingham, Birmingham, United Kingdom , 2 University Hospitals Birmingham NHS Foundation Trust, Department of Neurosurgery, Birmingham, United Kingdom , 3 University Hospitals Birmingham NHS Foundation Trust, Department of Radiology, Birmingham, United Kingdom , 4 Royal Stoke University Hospital, Stoke-on-Trent, United Kingdom Introduction: Surgical treatment of complex spinal tumours is challenging and often associated with significant morbidity. Tumour invasion of structures adjacent to the spine can be extensive, resulting in wide-ranging complications. Accurate assessment of invasion and prediction of intraoperative pitfalls using novel technologies can aid the implementation of preventative measures to improve patient care and outcomes. This study aims to validate the use of virtual three-dimensional (3D) models for complex spinal tumours and investigate whether the quantification of anatomical tumour invasion is predictive of intraoperative and postoperative outcomes. Material and Methods: This was a retrospective cohort study. Using commercially available neuronavigation planning software, virtual 3D models were developed for 31 patients who underwent en bloc resection of complex spinal tumours at Queen Elizabeth Hospital Birmingham between 2019 and 2024. Virtual 3D models were produced following the fusion of CT and MRI scans in a four-stage process: 1 - image selection and fusion, 2 - software reconstruction of anatomy, 3 - manual reconstruction of tumours, 4 - manual reconstruction of anatomy. A novel tool, the Scale of Anatomical Distortion (SAD) Index, was created following an extensive literature review. The SAD index contains four domains: neural, vascular, osseus, and soft tissue. It was retrospectively applied by four radiologists and six spinal surgeons to independently score tumour-induced changes using the virtual 3D models or 2D imaging alone. The utility of virtual 3D models and the predictive value of the SAD index was analysed. Results: Patient and tumour characteristics were representative of reported epidemiology. Questionnaire results revealed virtual 3D models to be representative of anatomy and well-received by surgeons. With respect to time required for the generation and analysis, virtual models are more practical than printed models (∼1h10 mins vs. 10-26 h). According to Cohen’s interpretation, the SAD index showed ‘moderate’ to ‘substantial’ inter-rater agreement across several domains. Tumour volumes and the SAD index scoring showed strong correlation and significant predictive accuracy (p < 0.05) for several outcomes, notably, excessive ITU stay (Area Under Receiver Operated Characteristic Curve (AUROC): 0.654-0.819), excessive postoperative hospital stay (AUROC: 0.712), and excessive operative length (AUROC: 0.666-0.793). Conclusion: Findings from this study support the use of virtual 3D models pre-operatively to aid in planning and shared decision making. Models are relatively easy to interpret and can be produced with minimal supervision, even by the less experienced members of the team. The SAD index is strongly predictive of several outcomes but requires optimisation to reduce subjectivity and improve accuracy. Further research is recommended, and avenues are available to explore the utility of models in patient education and surgical training. Isaac Arefi 1 , Kyle Behrens 1 , Benjamin Klein 1 , Hossein Elgafy 2 , Mina Tanios 3 1 University of Toledo College of Medicine, Education, Toledo, United States , 2 University of Toledo College of Medicine, Orthopedic Surgery, Toledo, United States , 3 Mid-Atlantic Physicians Group, Orthopaedic Surgery, Spine Surgery, McLean, United States Introduction: Cervical radiculopathy, often resulting from compression or irritation of the cervical nerve roots, leads to pain, sensory changes, and weakness along the nerve distribution. However, several non-spinal conditions, including hematological malignancies, post-surgical states, chemotherapy, and radiation therapies, can mimic these symptoms, complicating diagnosis and management. This review focuses on conditions such as multiple myeloma, acute lymphoblastic leukemia (ALL), post-thoracotomy, chemotherapy, and radiation-induced neuropathies that can present with radiculopathy-like symptoms. By exploring the clinical presentation and mechanisms of these mimics, we aim to improve the diagnostic accuracy in patients presenting with radiculopathy-like symptoms. Material and Methods: A comprehensive systematic review was conducted, including clinical studies, case reports, and reviews that detail conditions and therapies leading to radiculopathy-like symptoms. The review emphasizes the incidence of neurological symptoms post-thoracotomy, in hematological malignancies (e.g., multiple myeloma, ALL), and as a result of chemotherapy and radiation-induced neuropathies. Data on incidence rates, symptom characteristics, and underlying pathophysiological mechanisms were analyzed. Results: Radiculopathy-like symptoms are frequently observed across various conditions and treatment modalities. In post-thoracotomy patients, up to 40-50% experience neuropathic pain, with a portion displaying radiculopathy-like features. In hematological malignancies like multiple myeloma, up to 10-15% of patients develop symptoms due to vertebral involvement and compression of spinal nerve roots. ALL patients also exhibit radiculopathy-like symptoms in 3-5% of cases due to leukemic infiltration of the central nervous system. Additionally, chemotherapy agents such as vincristine and cisplatin are well-documented for causing peripheral neuropathy, often mimicking radiculopathy. Radiation therapy, particularly for head, neck, or thoracic malignancies, may also result in radiation-induced plexopathy or nerve damage, which mimics the distribution and symptomatology of cervical radiculopathy. The underlying mechanisms contributing to radiculopathy-like symptoms in these conditions vary significantly. In post-thoracotomy patients, nerve trauma during surgery leads to neuropathic pain and radiculopathy-like symptoms. In multiple myeloma and ALL, direct compression or infiltration of the nerve roots by tumor or leukemic cells is the main mechanism. Chemotherapy-induced neuropathies, particularly from agents such as vincristine, involve toxic effects on peripheral nerves, leading to pain, numbness, and muscle weakness, often mistaken for radiculopathy. Similarly, radiation-induced neuropathy results from damage to the nerve or surrounding tissues, leading to symptoms that closely resemble cervical radiculopathy. Differentiating between true cervical radiculopathy and these mimics requires a thorough evaluation, including imaging, laboratory tests, and a detailed treatment history to identify any contributions from chemotherapy or radiation. Misdiagnosis can delay appropriate therapy, so clinicians must maintain a high degree of suspicion, particularly in cancer patients undergoing chemotherapy or radiation. Conclusion: Radiculopathy-like symptoms can arise from various medical conditions and treatments, including surgical interventions, malignancies, chemotherapy, and radiation therapy. Recognizing the clinical and pathophysiological distinctions between these mimickers and true cervical radiculopathy is essential for accurate diagnosis and effective management. A multidisciplinary approach involving oncology, neurology, and surgery may be necessary for optimal patient outcomes. Further research is needed to identify diagnostic markers that can differentiate between these conditions and cervical radiculopathy more effectively. Stefano Telera 1 , Francesco Crispo 1 , Mario Lecce 1 , Fabrizio Rasile 2 , Edoardo Mazzucchi 2 , Francesco Dionisi 3 , Alessia Farneti 3 , Laura Marucci 3 , Francesca Giordano 4 , Monique Alonzi 4 , Roberto Gazzeri 5 1 IRCCS Istituto Nazionale Tumori “Regina Elena”, Neurosurgery, Roma , 2 IRCCS Istituto Nazionale Tumori “Regina Elena”, Roma , 3 IRCCS Istituto Nazionale Tumori “Regina Elena”, Radiotherapy, Roma , 4 IRCCS Istituto Nazionale Tumori “Regina Elena”, Anesthesiology and Intensive care, Roma , 5 Azienda Ospedaliera “San Giovanni Addolorata”, Pain Therapy, Roma Introduction: Treatment for patients presenting with spinal tumors is challenging and requires a multidisciplinary approach. Modern management of spinal metastases called Separation Surgery , may include the combination of decompressive and fixation surgery with stereotactic radiosurgery (SRS), once that adequate decompression of the spinal cord from tumor is achieved. Traditional techniques for spinal fixation in oncologic patients use titanium implants. However, the high atomic number of this metal may cause artifacts on postoperative CT scan or MRI imaging, reduce the radiation dose delivered to the spinal tumor due to scattering effect, complicate the interpretation of follow-up imaging and hinder an accurate dose calculation for spine SRS. Carbon-Fibre-Reinforced Polyetheretherketone (CFR-PEEK) presents a high biocompatibility, promote bone fusion and displays a low modulus of elasticity which closely match the bone. More importantly, carbon-fibre implants seem to perturb radiation doses far less than titanium implants, to allow a more precise delivery of radiosurgery to the tumor site sparing the neighbouring anatomic structures and due to their radiolucent properties aid in early local recurrence detection. Material and Methods: The results of combination of surgical treatment with CFR-PEEK implants and stereotactic radiosurgery have been analyzed in patients treated at our Institution in the last two years. Results: 6 patients have been treated following the principles of separation surgery in the last 24 months. The series include 4 female and two males. Mean age was 59.5 years (range 54-72). Primitive tumors include lung tumors (n° 2 cases); thyroid tumor n° 1 case); kidney tumor (n° 1 case); breast tumor (n° 1 case); retroperitoneal squamous carcinoma (n° 1 case). Median Tokuhashi score was 13 (range 9-15). Vertebral levels involved were L3 in four cases, D12 in one case, L1 in one case, median SINS score was 10.5 (range 9-13). Four patients belonged to RPA class I, one patient to RPA class II, one patient to RPA class III. Main symptoms include severe spine pain, which was present in all patients. Two patients had motor deficits. Surgical procedure includes a combination of spine decompression, percutaneous fixation, augmentation with silicone VK100. No postoperative complications were observed. In all patients a significant reduction of spine pain was achieved. SRS was performed within 4 weeks in all patients. Post-operative MRI did not present significant artefacts. All patients but one are still alive at a median follow-up of 7.5 months (range 4-12) and no breakage of the implanted materials have been detected. Conclusion: In our experience the combination of CFR-PEEK implants and stereotactic radiosurgery seem very promising in order to offer to selected patients, separation surgery and an adequate neuroradiological follow-up. Yusuf Brilliant 1 , Muhamad Aulia Rahman 2 1 Public Hospital Kanudjoso Djatiwibowo Balikpapan, Neurosurgery, Balikpapan, Indonesia , 2 Public Hospital Brebes, Neurosurgery, Brebes, Indonesia Introduction: Surgical excision is the most recommended treatment for symptomatic lumbar extradural cysts with endoscopic technique as the main choice procedure. Recently, biportal endoscopic spine surgery also gradually used for discectomy, decompression and fusion surgery. This procedure lately use in non-infectious disease. Case: a 38 years old male come with repetitive low back pain and radiculating to the left knee for several years, was diagnosed with extradural cyst of 3th - 4th lumbar and local spinal canal secondary stenosis. We decided to use the intralaminar unilateral biportal endoscopic technique for decompression and removal extradural mass lesions for this patient. We reported the result of this procedure, pre operative and postoperative symptoms, operative radiology and also pathological result. Result: Postoperative pain decreased clinically for the patient without any additional neurological deficit. The pathological result was confirmed as an extradural cyst. Conclusion: Biportal endoscopy may be an alternative surgical procedure for symptomatic lumbar intraspinal extradural cyst lesion. With advantages such as early recovery, minimizing trauma for normal structures and magnified endoscopic view. Meddeb Mehdi 1 , Safouen Ben Brahim 1 , Hachicha Hassan 1 , Chaker Mohamed 1 , Hassen Makhlouf 1 , Mondher Mestiri 1 1 Kassab Institute, Adults, Manouba, Tunisia Introduction: Solitary bone plasmacytomas (SBP) are localized plasma cell malignancies involving bone marrow. It is a rare entity and, in the spine, it mainly concerns the dorsolumbar vertebrae. Involvement of the sacral spine is rare and a more challenging condition. Material and Methods: A 59-year-old woman presented and admitted with sacral pain and neurological distal deficit of the lower left limb, evolving for 2 weeks and becoming resistant to symptomatic treatment. X-ray showed no abnormalities. CT scan has showed a lytic lesion of the sacrum, invading the dural sheath with intra-canal extension and coming into contact with the sacroiliac joints. MRI concluded signal abnormality in the first three sacral vertebrae, well-defined, coming into contact with the S1 nerve roots. An etiological investigation, including clinical, biological, and radiological assessments, did not yield conclusive results. The diagnosis of solitary plasmacytoma was confirmed based on histopathological examination via vertebral biopsy. Results: The patient was reviewed in the hematology department and she received both postoperative radiotherapy and chemotherapy. She remains with no sacral pain. The neurological deficit has remained stable at the last follow-up after one year. Conclusion: Although, SBP is a rare diagnosis especially in the sacral spine, it should be included in the differential diagnosis for acute sacral pain with neurological deficit. The case reported here support the views that SBP is responsive to radiotherapy and chemotherapy. Sharif Ahmed Jonayed 1 1 National Institute of Traumatology and Orthopaedic Rehabilitation, NITOR, Spine Surgery, Dhaka, Bangladesh Introduction: The anatomical characteristics of spinal GCT have historically been regarded as an extremely unpredictable bone tumor and still present challenges to surgeons. Advancements in surgical techniques and adjuvant therapies have provided new options for treatment, evidence-based algorithms are lacking. Complete surgical resections of SCGT resulted in the lowest recurrence rates. However, morbidity of en bloc resections is high. Several recent advancements in adjuvant therapy may hold promise for decreasing SGCT recurrence, specifically stereotactic radiotherapy, selective arterial embolization, and medical therapy using denosumab and interferon. Purpose: This is case of GCT in the L1 vertebra with extensive paravertebral soft tissue involvement. Our focus is to emphasize the importance of considering GCT as a diagnosis and guiding the proper peri and post-operative management on surgical treatment. Case history: A 21-year-old previously healthy woman presented with a 4-month history of continuous progressive back pain and weakness of lower limb. She denied history of injury and any underlying diseases. Physical examination showed that she was systematically well in appearance. She was found to have motor weakness (MRC 3/5 -right, 1/5 -left) in the lower limb and was bed retained with intact bowel and bladder function. Plain radiograph showed pathological fracture of L1. CT and MRI of the spine revealed significant bone destruction and pathological fracture of L1, secondary spinal canal stenosis, and extensive paravertebral soft tissue mass around L1. Routine laboratory studies were almost within normal range. Considering the large volume of the mass and soft tissue invasion, wide local excision including vertebral component resection (VCR) through posterior approach and chemical cauterization was designed. Posterior spinal canal decompression, internal fixation and reconstruction with cylindrical cage was performed. Peri and postoperative recovery were uneventful. She was allowed to ambulate with orthosis post operatively. The postoperative pathology confirmed a GCT. She has then received the treatment with subcutaneous injections of 120 mg denosumab with loading doses on days 8 and 15 of cycle 1 and will continue for a total of 12 months. Daily supplements of vitamin D and a calcium supplement is prescribed orally to avoid hypocalcemia. No major complications were associated with surgical treatment and denosumab administration. She is on our regular follow-up for evaluation of her symptoms, physical examination and radiological imaging assessments. Conclusion: Complete surgical resection of SGCT should be the goal when possible, particularly if neurologic impairment is present. Combination of surgical treatment and denosumab treatment can be a definite therapy of choice in treating large GCTs at challenging anatomical locations, such as the spinal regions. These tumors should be approached as a case-by-case problem, as each presents unique challenges. Collaboration of spine surgeons, radiation oncologists, and medical oncologists is the best practice for treating these difficult tumors. Our case highlights the significance of early diagnosis and proper treatment of GCT of the spine with soft tissue invasion has not been previously well reported. Keywords: Spinal giant cell tumor, Treatment modality, Denosumab, Outcome Vadim Byvaltsev 1,2,3 , Andrei Kalinin 1,3 , Roman Polkin 1 , Adil Satov 4 , Michail Biryuchkov 4 , K. Daniel Riew 5 6 1 Irkutsk State Medical University, Neurosurgery, Irkutsk, Russian Federation , 2 Irkutsk State Medical Academy of Postgraduate Education, Traumatology, Orthopedic and Neurosurgery, Irkutsk, Russian Federation , 3 Railway Clinical Hospital, Neurosurgery, Irkutsk, Russian Federation , 4 West Kazakhstan Marat Ospanov Medical University, Neurosurgery, Aktobe, Kazakhstan , 5 Columbia University, Orthopedic Surgery, New York, United States , 6 Weill Cornell Medical Schoo, Neurological Surgery, New York, United States Introduction: The modern paradigm of minimally invasive spine surgery (MISS) places significant emphasis on preserving bony and surrounding ligamentous and muscular structures. The proposed technique of approach and reconstruction of the spinal canal preserves the idea of minimally invasive and reconstructive surgery and is an alternative to traditional laminectomy, which is widely used in patients with spinal cord tumors. Material and Methods: 34 cases of SCT resection using a modified technique were retrospectively analyzed from 2010 to 2023. The McCormick scale was used to evaluate neurologic outcomes. CT, MRI and X-ray data were used to analyze the stability of the posterior support complex after surgical treatment, to measure the spinal canal area, to assess the volume of paraspinal muscles and to assess the development of progressive deformity. The frequency of progressive spinal deformity was defined as the progression of scoliosis or kyphosis greater than 10° of the Cobb angle on X-ray. Results: In the study group, the median age was 50.5 years (from 30 to 81 years). The average duration of neurological symptoms or pain syndrome was 24.4 days (from 2 to 72 days). When studying clinical manifestations in the operated patients, the majority of cases revealed: back pain (97%), radicular pain syndrome or dermatome-type sensitivity disorders (79.4%), decreased strength in the upper or lower extremities (47%). When perioperative parameters were analyzed, the mean operative time was 353 ± 106.3 min, the volume of blood loss was 305 ± 217.2 ml, and the mean hospitalization time was 10 days (from 2 to 26 days). Analysis of the spinal canal area revealed no signs of stenosis in the postoperative period. The median area according to preoperative MRI was 195 mm 2 (183; 215) and 205 mm 2 (189; 215) after 12 months of follow-up (p < 0.00001). CT measurements were 236 mm 2 (230; 276) preoperatively and 267 mm 2 (240;330) after 12 months (p < 0.00001). Analysis of paraspinal muscle degeneration revealed no clinically significant decrease in area caused by muscle damage or atrophy. The mean area was 513.2 mm 2 (353; 729) preoperatively and 476.7 mm 2 (356; 659) after 12 months of follow-up (p = 0.0001). Analysis of paraspinal muscle degeneration showed no clinically significant decrease in area caused by muscle damage or atrophy. In the analysis, there were no cases of deformity development at the operated level. The mean Cobb angle was 4.5 degrees (2.1; 8.4) and 4.4 degrees (2.3; 8.1) 12 months after surgery (p = 0.82). When neurologic outcomes were analyzed using the McCormick scale preoperatively, the median corresponded to a grade of 2 (2;3). After 12 months of postoperative follow-up, there was an improvement in the dynamics of neurologic status corresponding to McCormick grade 1 (1;1) (p < 0.0001). Conclusion: Laminectomy and laminar reconstruction allows for maximal visualization and manipulation of the tumor, followed by restoration of the dorsal roof of the spinal ring, as well as well as the structures of the posterior osteo-ligamentous support complex, preventing stenosis and deformation of the spine at the operated level, while preserving the original volume of the paraspinal muscles. Si Jian Hui 1 , Naresh Kumar 1 , Priyambada Kumar 1 , Gabriel Leow 1 , Rohan Parihar 1 , Jiong Hao Tan 1 1 National University Hospital, National University Spine Institute, Singapore, Singapore Study Design: Narrative review. Background: Carbon-fiber reinforced Polyetheretherketone (CFR-PEEK) instrumentation has been described in recent years for use in MSTS. Benefits of CFR-PEEK include reduction of imaging artifacts, allowing for more efficient follow-up and adjuvant therapy planning as compared to traditional titanium implants. Despite the increase in CFR-PEEK usage in literature, there is currently no technical guide or considerations in terms of usage of CFR-PEEK in MSTS. Hence, we aim to highlight various important technical considerations and potential pitfalls for surgeons when utilising CFR-PEEK instrumentation in MSTS. Materials and Methods: This narrative review was conducted using PubMed, Medical Literature Analysis and Retrieval System Online (MEDLINE), The Cochrane Library and Scopus databases through 30 June 2024. All studies that were related to CFR-PEEK instrumentation in MSTS were included. The vast personal experiences of the senior authors with CFR-PEEK instrumentation also circumstantiated the concepts highlighted in this paper. The CFR-PEEK instrumentation system used by our senior author was ICOTEC Blackarmour implants. Results: A total of 43 studies were included in this review. We discussed various considerations when planning for CFR-PEEK instrumentation in MSTS patients. These factors include pre-operative construct planning, as CFR-PEEK rods cannot be cut or contoured depending on the patient’s requirement intra-operatively and may restrict their use in long constructs and complex spinal deformities, where the surgeon has to consider using a hybrid construct with conventional titanium rods instead. The intra-operative handling of the CFR-PEEK system is another consideration, as CFR-PEEK pedicle screws, being radiolucent, are difficult to visualize during placement under intraoperative imaging, especially to the untrained eye. CFR-PEEK pedicle screws are also not self-tapping and weak in torsion, due to which they require line-to-line tapping over the guidewire. It is important to be aware of the risk of guide-wire advancement or dislodgement that may result due to line-to-lint tapping. Post-operatively, considerations for radiotherapy (RT) planning are also important, taking into account the usage of hybrid constructs with CFR-PEEK screws closer to the tumour bed and titanium screws further away from the tumour epicentre, to reduce over costs for patients whilst maintaining the imaging advantage of CFR-PEEK screws for RT planning post-operatively. Conclusion: In our manuscript, we are the first to highlight various considerations for MSTS surgeons to take into account when utilising CFR-PEEK instrumentation. This serves as an important guide for surgeons treating MSTS, with the continuous evolvement of our treatment capacity in MSD. Level of Evidence: IV. Keywords: Carbon-Fiber, PEEK, Spine, Tumour, Implant, Instrumentation Charles Taylor 1 , Luqman Hamed 1 , Priyanshu Saha 1 , Liam Rose 1 , Hasan Raza 1 , Jason Bernard 1 , Tim Bishop 1 , Darren Lui 1 1 St George's Hospital, Orthopaedics, London, United Kingdom Introduction: Paediatric chordomas are rare malignant tumours with significant recurrence rates and treatment challenges. In the UK they are usually referred to specialist primary tumour centres for consideration of en bloc resection. However, such cases are associated with high recurrence and seeding rates. Proton beam therapy (PBT) has therefore become a preferred treatment modality due to its precise targeting capabilities and reduction in local recurrence. Consequently, separation surgery is now an established technique to circumferentially decompress metastatic tumour from the spinal cord with a minimum 2mm clearance to allow for Stereotactic body radiotherapy. This in turns allows the patient to undergo radical treatment considered to be potentially curative. Materials and Methods: This study presents the first case of serendipitous separation surgery and the use of post adjuvant proton beam therapy in a 10-year-old male diagnosed with a large multi-lobulated extradural chordoma on the left C2-3 and C3-4 foramina with extension into the vertebral canal spanning C1 to C4. This study also explores the use of a vascularised fibular strut graft to avoid instrumentation in the correction of a Proximal Junctional failure (PJF) in a growing child dependent on surveillance imaging. Results: Following complete removal of the intra-canal lesion, the patient was discharged to the paediatric intensive care unit for 2 days before step-down. Post-operative imaging revealed interval posterior decompression of C3-C4 with satisfactory debulking of the lobulated lesion. This patient showed complete remission at 1 year on PET CT and MRI and consequentially had received successful serendipitous separation surgery. At follow up cervical stabilization using a vascularized fibular strut flap was performed to correct a PJF with associated spinal cord kinking. Conclusion: This study is the first to report serendipitous separation surgery in the case of a complex paediatric cervical chordoma. This study demonstrates good post-operative outcomes at 5 year follow up with no reoccurrence of disease and also evaluates the use of a vascularized fibular strut flap as an effective surgical solution for managing post-radiation cervical deformities. José Poblete Carrizo 1 , Julio Gonzalez Vasquez 2 , Joaquim Enseñat Nora 1 , Jorge Torales 1 1 Barcelona University, Neurosurgery, Barcelona, Spain , 2 INDISA Clinic, Santiago, Chile Objective: To evaluate the effectiveness and safety of the posterolateral approach in the en bloc resection of Pancoast-type tumors. Introduction: Pancoast tumors were initially described in 1924 by the eponymous author and are defined as superior pulmonary sulcus tumors. They present infrequently (5% of non-small cell lung tumors) and their management is often complex and challenging. Many groups in the literature describe combined approaches to achieve “en bloc resection.” Here, we present a case series where a one-stage posterolateral approach with en bloc resection and instrumentation was performed, and we evaluate the results and 5-year follow-up. Materials and Methods: This is a retrospective descriptive study of a consecutive case series of en bloc resection in patients with Pancoast tumors with vertebral involvement, instrumentation, and 360° stabilization. A 5-year follow-up was conducted to assess the degree of resection, perioperative complications, and deformity. Results: Eight male patients were included, with a mean age of 56 years, and all had histological confirmation. The most common histological type was squamous cell carcinoma (62.5%), followed by adenocarcinoma (37.5%). En bloc resection was achieved in all cases. Regarding complications, two patients presented minor complications (1 fistula and 1 wound dehiscence with infection), and no major complications were recorded. At the 5-year clinical follow-up, 6 patients had disease-free survival, 1 patient died, and 1 experienced a recurrence. There were no records of instrumentation failure. Conclusions: En bloc resection of locally aggressive Pancoast tumors is feasible via a posterolateral approach and appears to be a safe and effective alternative. The 5-year follow-up shows promising outcomes. Emanuela Asunis 1 , Chiara Cini 2 , Giovanni Barbanti Bròdano 2 , Gisberto Evangelisti 2 , Marco Girolami 2 , Valerio Pipola 2 , Giuseppe Tedesco 2 , Riccardo Ghermandi 2 , Stefano Bandiera 2 , Silvia Terzi 2 , Stefano Boriani 3 , Alessandro Gasbarrini 2 1 Rizzoli, Chirurgia Vertebrale, Bologna, Italy , 2 Rizzoli, Bologna, Italy , 3 IRCCS Ospedale Galeazzi - Sant’Ambrogio, Milan, Italy Introduction: Primary malignant bone tumors are exceedingly rare, with an incidence of 0.5 to 1 per million, and sacral localization is even more uncommon, representing only 1-3.5% of these tumors. These malignancies are often diagnosed late due to their asymptomatic nature until they present as large, advanced intrapelvic tumors. Management is complicated by the need for precise surgical intervention and the consideration of adjuvant therapies based on tumor histology and patient factors. This study aims to analyze outcomes and complications associated with sacrectomy performed for primary malignant bone tumors and recurrent sacral metastases. We assess surgical approaches, resection margins, recurrence rates, survival, and postoperative complications in a cohort of patients undergoing this challenging procedure. Material and Methods: We conducted a single-center, retrospective analysis of patients who underwent complete, partial, or hemisacrectomy for primary malignant bone tumors or recurrent sacral metastases. Excluded were patients with metastatic disease not necessitating sacrectomy. Data collected included demographics, clinical characteristics, tumor types, resection status, adjuvant therapies, recurrence, metastasis, and complications. Surgical approaches were categorized as posterior, anterior, or combined anterior-posterior. The primary outcomes were overall survival rate and disease-free survival rate. Secondary outcomes focused on complication rates and functional results. Results: The study included 20 patients (10 females, 9 males) with a mean age of 47.8 years at the time of surgery. Primary malignancies were present in 90% of patients, including chordoma, giant cell tumor, spindle cell sarcoma, chondrosarcoma, osteoid osteoma, and malignant myofibroblastic tumor. Postoperative radiation therapy was administered to 25% of patients, and 10% received chemotherapy. Surgical approaches varied: 10% underwent double access, 5% anterior access only, and the remainder had posterior approaches. High partial sacrectomy (above S3) was performed in 25%, while low sacrectomy (at or below S3) was done in 75%. Complete resection with clean margins (R0) was achieved in 65% of cases, while 35% had R1 resections with microscopic tumor remnants. Root resection was necessary in 20% of patients. Local recurrence occurred in 25% of patients, with two requiring reoperation and neurological sacrifice. Distant metastasis was observed in 10% of cases, with embolization performed in one instance. Postoperative complications affected 60% of patients. The most common issues were surgical wound dehiscence with delayed healing (35%) and visceral changes affecting the bowel and urination (25%). No mechanical complications were reported. Conclusion: Technological advancements and refined surgical techniques have improved the efficacy of sacrectomy, yet challenges remain. Future research should focus on optimizing surgical approaches, reducing complication rates, and enhancing long-term oncologic and functional outcomes. Image-guided surgery and predictive models hold promise for better outcomes and personalized treatment plans. This study underscores the complexity of sacrectomy and the need for ongoing evaluation and improvement in surgical and postoperative strategies. Venkatesh Dasari 1 , Navin Singh 1 , Kartik Soni 1 , Masih Sabri 1 , Saikat Roy 1 , Aditya Sundar Goparaju 2 1 Raipur Institute of Medical Sciences, Raipur, India , 2 Care Hospital, Raipur, India Introduction: Spinal cord tumors constitute a less travelled path in the field of spine surgery, specifically due to it’s rare nature and hence limited training. These tumors may arise from Meninges, Nerve Root, Spinal Cord and other structures in spine, and can be benign as well as malignant. Majority of the time these are incidentally and/or surprisingly found in imaging studies while managing suspected cases of Cervical/Dorsal Myelopathy, UMN/LMN Paresis, and even bladder/bowel disturbances. Spinal cord tumors can be divided into ExtraDural, IntraDural-ExtraMedullary, and Intra-Medullary, in decreasing pattern of incidence. As per general trends of practice and level of understanding & training, ExtraDural and IntraDural-ExtraMedullary cases are being operated by even Spine Surgeons in India, while neurosurgeons operate all including Intra-Medullary cases. This retrospective study is a compiled outcome of 16 cases of spinal cord tumors, including ExtraDural & IntraDural-Extramedullary cases which were managed surgically in the Spine Surgery Unit, in a single center medical college setup in rural central India. Material and Methods: 16 Patients with diagnosed Spinal Cord tumors who underwent surgery from March 2023 to August 2024, over the period of 1.5 years were included in this study, excluding the Intra-Medullary Cases. These patients presented with various complains including radicular pain, patchy weakness and bowel-bladder disturbances. Pre-surgery data including demographics, Contrast Enhanced 1.5Tesla MRI scans, ands routine investigations, along with detailed clinical and neurological examination were recorded. The patients were followed up till 6 months post-surgery and Owestry Disability Score, American Spinal Injury Association (ASIA) grading, SF-36 Questionnaire, Nurick’s Grading of Disability, and Neurocharting was monitored serially. The patients underwent surgery under operating microscope and surgical loupes, under the Spine Surgery Unit. Detailed histopathological examination was done for all. Results: With the mean age of 58 ± 2.4 years, there was a female pre-disposition (62.5%) amongst the cases. Majority cases were IntraDural-ExtraMedullary with the most common tumor was found to be Schwannoma (37.5%), followed by Meningiomas (25%), Neurofibromas (18.75%), Myxopapillary Ependymoma (12.5%). Only One case of ExtraDural tumor was found to be a Lipoma (6.25%). Majority of the cases were of Dorsal spinal cord (93.75%) with only the ExtraDural Lipoma being Lumbar (6.25%). Gross total resection was achieved in 75% of the cases. There was significant improvement in all follow up scores, with no neurological deterioration. There was CSF leak in one case (6.25%) which re-exploration and repair. Conclusions: The surgical management of spinal cord tumors remains a challenging yet underexplored area in spine surgery. While advancements in surgical techniques have improved outcomes, there is still much to be learned about optimizing patient care. Given the complexity and potential risks associated with these procedures, it is essential that spine surgeons place greater emphasis on this field, dedicating more research and training to improve outcomes. As a road less traveled in spine surgery, spinal cord tumor resection deserves heightened attention to ensure better long-term prognosis and quality of life for patients. Georgios Zilidis 1 , Clare Jacobs 2 , Gerard Mawhinney 3,3 , Jeremy Reynolds 4 , Yaron Berkowitz 5 , Emma Kenney-Herbert 6 , Ather Siddiqi 7 , James Teh 8 , Basavaraj Chari 8 , Martin Gillies 9 , Tim Mccormick 10 , Ami Sabharwal 7 , Stana Bojanic 11 , Hayley Jones 6 , Alex Anderson 12 , Claire Worrall 12 , Niamh Louwman 12 , Harriet Dent 12 , Mariam Latif 10 , Tomasz Bajorek 13 , Victoria Bradley 12 , Nicolas Beresford-Cleary 1 1 Oxford University Hospitals, Oxford Spinal Surgery Unit, OxMINT, Oxford, United Kingdom , 2 Oxford University Hospitals, Department of Clinical Oncology, Churchill Hospital, OxMINT, Oxford, United Kingdom , 3 Oxford University Hospitals, Oxford Spinal Surgery Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom , 4 Oxford University Hospitals, Oxford Spinal Surgery Unit, Oxford, United Kingdom , 5 Oxford University Hospitals, Department of Musculoskeletal Radiology, Experimental Medicine Division, Nuffield Department of Experimental Medicine, University of Oxford, Oxford, United Kingdom , 6 Oxford University Hospitals, Department of Clinical Oncology, Churchill Hospital, Oxford, United Kingdom , 7 Oxford University Hospitals, Orthopaedic Oncology and Arthroplasty, Oxford, United Kingdom , 8 Oxford University Hospitals, Department of Musculoskeletal Radiology, Oxford, United Kingdom , 9 University of Oxford, Neurosurgery, Oxford, United Kingdom , 10 Oxford University Hospitals, Department of Anaesthesiology, Oxford, United Kingdom , 11 Oxford University Hospitals, Neurosurgery, Oxford, United Kingdom , 12 Oxford University Hospitals, Department of Palliative Medicine, Oxford, United Kingdom , 13 Oxford University Hospitals, Department of Psychiatry, Oxford, United Kingdom Introduction: Metastatic or secondary bone tumours are known to be associated with skeletal-related events, such as pathological fractures, spinal cord compression, or hypercalcemia. These deposits are often highly painful and cause significant functional impairment and harm to quality of life. We would estimate based on rising prevalence of cancer in the UK predicted to reach 3.5million in 2025, the number of patients living with bone metastases will reach epidemic proportions. There are a growing number of treatment options available to patients many of whom have variable physiological frailty due to their advanced malignancy. Clinical decision making around the best intervention across the spectrum of possibilities from major surgery, radiological, neuromodulatory or anaesthetic procedures to supportive pharmacotherapy is extremely challenging and current scores to guide this are specialty specific and thus lack the breadth of approach necessary to guide intervention in a landscape with many options. Methods: We will describe a feasibility study looking at traditional medical statistics and machine learning and artificial inteligence to develop and test a clinical decision aid to support patient choice around appropriate levels of intervention. Our longer term aim is to bring together traditional single specialty scoring systems like the Spinal instability neoplastic score the Tokuhashi Scoring System, Eastern Cooperative Oncology Group, Karnofsky Performance Scale and imaging data to create a comprehensive decision-making framework with the support of collaborating and data sharing organisations in both Europe and North America. Results: We hope to present a first draft decision guide which would support informed joint decision making with patients without additional burden to patient or clinician. Conclusion: Clinical decision making in any setting is challenging but in a multi-specialty environment with frail and co-morbid patients with finite prognosis the stakes are higher than ever. We aim to present the results of a feasibility study into how we might develop a clinical decision guide to support patients and clinicians in this setting. Victoria Yushenko 1 , Artem Ilgeldiev 1 , Yahya Habib 1 , Anne Carolus 1 , Veit Braun 1 1 Diakonie Jung-Stilling Hospital, Neurosurgery, Siegen, Germany Introduction: Primary melanoma of the spinal cord is a rare pathology, with less than 70 cases reported in the literature since 1906. Hayward's classification of primary spinal cord melanoma relies on the absence of a melanoma outside of the spinal cord and histologic confirmation of melanoma. We present the case of a 77-year-old female who was referred to our neurosurgical outpatient clinic with a one-year history of progressive gait disturbance and lower extremity ataxia. Her symptoms initially began a year prior when she was admitted to an external hospital for acute back pain, a history of multiple falls, and a background of atrial fibrillation managed with Marcumar. Initially lower limb ataxia was noted, but no other neurological deficits were identified. A head CT scan revealed dilated ventricles, and further MRI of the head, neck, and thoracic spine showed an intradural extramedullary hematoma at the Th6-9 levels with compression of the spinal cord and complete obliteration of the spinal canal. Additionally, syringomyelia was noted above the mass. After reversing the anticoagulant effects of Marcumar, the patient received an external ventricular drainage and was transferred to the ICU. Upon examination, the lower limb ataxia remained unchanged and a new urinary incontinence was noted. Surgical decompression of the hematoma was not pursued. The patient was then transferred to a rehabilitation center. At the initial visit in our clinic one year later, an MRI of the thoracic spine revealed an intraspinal, extramedullary lesion with homogeneous contrast enhancement between the Th6-9 levels. The patient subsequently underwent subtotal resection of the lesion, a complete resection was not possible due to an infiltrative character of the mass. Histopathological analysis confirmed the diagnosis of malignant melanoma. A comprehensive diagnostic work-up was performed, including MRI of the spinal axis and head, a full-body PET scan, and upper GI-endoscopy as well as colonoscopy. Additionally, gynecological, maxillofacial, ophthalmological, and dermatological evaluations were conducted. No other lesions were identified. The case was reviewed in an interdisciplinary oncology conference, where radiation therapy followed by chemo- and immunotherapy was recommended. Material and Methods: An extensive literature review was conducted using PubMed's electronic database to provide an updated overview. Results: CNS metastasis from melanoma is the third most common cause of metastatic disease to the CNS, while primary CNS melanoma accounts for only 1% of all cases. Primary spinal cord melanoma is even rarer. Primary spinal cord melanoma is most commonly found in the cervical and thoracic regions. The most frequent symptoms include weakness and paresthesia of the extremities. MRI is the preferred diagnostic tool, although it does not provide specific features to distinguish primary spinal melanoma from other tumors. While gross total resection is the primary surgical goal, the extent of resection is not directly linked to overall survival. Patients who receive a combination of surgery and adjuvant therapy, however, tend to have improved median survival rates. Conclusion: This case highlights the challenges in diagnosing primary spinal cord melanoma and emphasizes the importance of a thorough diagnostic work-up. Ethics committee approval: 2024-011-f-S Artem Ilgeldiev 1 , Victoria Yushenko 1 , Anne Carolus 1 , Yahya Habib 1 , Johannes Dillmann 1 , Veit Braun 1 1 Diakonie, Jung-Stilling Hospital, Neurosurgery, Siegen, Germany Introduction: This study investigates patients diagnosed with hematogenous spondylodiscitis (M46.4) and spinal metastases (C41.2) in the thoracic spine, both of which cause secondary spinal canal narrowing and spinal cord compression. The goal is to explore correlations between radiological findings and factors that predispose to neurological impairment. Materials and Methods: Radiological data was systematically assessed and compared with neurological exams. The following scales were utilized: • Weinstein-Boriani (WB) • Epidural Spinal Cord Compression (ESCC) • Axial MRI residual spinal canal measurements in percentage • Tomita-Score Results: The study included 23 M46.4 patients and 51 C41.2 patients, with statistically significant male predominance (p = 0.452267) in both groups. Patients with spondylodiscitis were younger than 65, while those with spinal metastases were typically older, with 17% over 85 years. Spondylodiscitis mainly affected the lower thoracic spine, sparing the rigid Th1-Th2 region. In contrast, no Th4/5 involvement was observed in the C41.2 group, a statistically significant difference (p = 0.002475). Residual canal space in M46.4 ranged from 38% to 100% (median 88%, mean 77%), while in C41.2 it ranged from 4% to 100% (median 31%, mean 44%), with a significant difference (p = 0.000397). There was a direct correlation between reduced residual canal space and severe neurological deficits, especially in C41.2 patients. Neurological deficits were observed in 61% of M46.4 patients preoperatively (26% ASIA A p = 0.004926) with more severe impairments in those with intraspinal abscesses or empyemas. In the C41.2 group, 59% had neurological deficits (17% ASIA C, 18% Spinal ataxia; p = 0.0258 Fisher exact test). WB combinations A, B, C, D appeared in 64.7% of cases, corresponding to ESCC 3, indicating maximal or near-maximal stenosis. ESCC grading showed high accuracy (Spearman's correlation 0.785952, p < 0.05). A negative correlation was found between WB (WB 1-12) and residual spinal canal diameter (Spearman's correlation = -0.376933, p < 0.05), confirming the WB scale’s diagnostic value. Inflammatory spinal changes in spondylodiscitis corresponded to higher Tomita types (5-6) compared to C41.2 (4-5). However, the Tomita score did not predict neurological deficits, nor did the growth rate of metastases. CRP levels showed opposing trends, decreasing in M46.4 patients but increasing in C41.2 patients during treatment, suggesting distinct disease dynamics. Conclusion: This study demonstrates a significant correlation between radiological findings and neurological deficits in thoracic spinal pathologies. Spinal canal narrowing, assessed using WB and ESCC scales, was closely linked to neurological impairment, in the M46.4 group neurological deficits were more severe than in the C41.2 group. The WB and ESCC scales proved valuable in predicting neurological deficits, supporting their use in clinical decision-making. Ethics committee approval: 2024-011-f-S Zohra Souei 1 , Atef Ben Nsir 1 , Elouni Emna 1 , Affes Ameur 1 , Wiem Boudabbous 1 1 Fattouma Bourguiba, University Hospital of Monastir, Department of Neurosurgery, Monastir, Tunisia Introduction: Malignant schwannomas are uncommon primary tumours of nerve sheath origin. They are rarely found within the spine and spinal canal, and little is known about their management in this unusual location. Material and Methods: We report the case of a 31-year-old patient who presented to our department with heaviness in both lower limbs. Examination revealed spastic paraparesis and a T7 sensory level. Imaging identified an intra-dural extramedullary tumor lesion at the D7 level, with extension into the spinal canal and compression of the spinal cord. A subtotal tumor resection was performed via a posterior approach. Histopathological examination confirmed the diagnosis of a benign schwannoma. Results: The patient was readmitted four months later due to neurological deterioration caused by tumor recurrence, which had progressed to involve the D7 and D8 vertebral bodies, with mediastinal extension and pulmonary invasion. A biopsy was performed, and histological examination confirmed malignant transformation. The patient underwent adjuvant radiotherapy, but this did not result in significant clinical improvement. Unfortunately, the patient passed away a year later from acute respiratory failure. Conclusion: Benign spinal schwannomas with malignant transformation are exceptional. The diagnosis should be raised in the setting of an abnormal tumor growth and an more aggressive behavior. The prognosis remains poor in the majority of cases despite multimodal treatment. Wièm Mansour 1 , Ghassen Gader 1 , Mohamed Amine Gharbi 2 , Bahri Farah 1 , Hdhili Houssem 1 , Aziz Bedioui 1 , Mohamed Zouaghi 1 , Mouna Rkhami 1 , Mohamed Badri 1 , Kamel Bahri 1 , Zammel Ihsen 1 1 Trauma and Burns Center, Department of Neurosurgery, Ben Arous, Tunisia , 2 Monji Slim Hospital, Department of Orthopedics, Tunis, Tunisia Introduction: Ewing’s sarcoma is the third most common malignant bone tumor after osteosarcoma and chondrosarcoma in adolescents and young adults. It represents the undifferentiated form of primitive neuroectodermal tumors. The pelvis is the most frequent location of this tumor, followed by the femur, humerus and scapula. Vertebral location is seldom. Observation: We report the cases of a 10-year-old girl, and a 24-year-old man. In both cases, cauda equina syndrome was the reason for hospitalization. Our patients had a lumbar MRI showing an expansive intra-canal process. Both had an emergency decompression procedure followed by adjuvant treatment. Discussion: Genetically, Ewing's sarcoma is related to a characteristic t (11; 22) chromosomal translocation. All the bones of the skeleton may be affected, but in different proportions as they are mainly diagnosed in the flat bones. Vertebral location accounts for 3.5% to 15% of all lesions. Molecular biology has an essential place for prognosis. MRI is the key exam to appreciate local extension and for therapeutic decision. The prognosis of Ewing's sarcoma is poor in the vertebral location. But some authors report different outcomes between sacral and extrasacral locations. Conclusions: The management of Ewing's sarcoma is based on a combination of surgery, radiotherapy and chemotherapy. Despite the therapeutic progress, the prognosis of this localization remains reserved. Luis Rodríguez Pino 1 , Bolos Ten Laura 2 , Antonio Martín-Benlloch 2 , Disch Alexander C. 1 1 University Center of Orthopaedics, Traumatology & Plastic Surgery and University Comprehensive Spine Center (UCSC), Dresden, Germany , 2 Spine Surgery Unit, University Hospital Dr. Peset, University of Valencia, Valencia, Spain Introduction: En bloc spondylectomy (EBS) is a technique that allows aggressive resection of a spinal tumor in selected cases. The small number of cases of extradural primary tumors, the rare scenario of solitary metastases and the complexity of the procedure lead to the technique being performed in specialised centres with the support of a multidisciplinary team. The aim of this study was to analyse aggressive resections and reconstructions in a multicentric setting, particularly with regard to mechanical complications and to provide evidence to recommend the optimal reconstruction technique depending on the preexisting conditions. Material and Methods: A total of 63 patients (35 M and 28 F) with a mean age of 47.9 years (SD 16.8) treated between 2015 and 2022 were analysed. Thirty-five cases were included at the University Hospital of Dresden, Germany, and 28 cases at different university hospitals in Valencia, Spain. 36 primary spinal tumours and 27 solitary metastases were indicated for EBS. The distribution of cases between the two entities was similar in both countries. The most common entities for metastases were breast cancer (16%), and chordoma as primary spinal tumour (15%). Results: The centres used comparable implant materials for spinal reconstruction after aggressive resection. The majority of cases analysed involved at least 2 segments above and below the defect (86% of cases). The remaining cases fusing less than 2 segments below included mainly lower lumbar reconstructions. We observed a total of 11 cases (17%) of material failure. The majority (63%) of reconstructions showed complications at the thoracolumbar junction, but all cases demonstrated construct failure at the lumbar spine. CFR-PEEK materials were used in 63% of cases. In 45% of cases, a post-operative infection was observed before or during material failure. Patients who were primarily stabilised with CFR-PEEK material showed a higher incidence of complications (higher failure rate, 100% revision rate) compared to titanium constructs. Revision procedures were performed by changing the rod to titanium and/or implanting a double-rod construct. Conclusion: The results presented show, as previously described in the literature, a higher rate of mechanical complications in the thoracolumbar and particularly over long instrumentations at the lumbar spine, especially in cases where CFR-PEEK materials were used for reconstruction. Although the data correlates with published results, it should be considered that a small sample size and an overall lower complication rate may wrongly influenced the outcome. The study presented here clearly shows, that there is room for improvement in planning and proceeding reconstruction following major spinal resections. It paves the way for further analysis and research into potential planning errors, the avoidance of which has already shown a significant improvement in patient outcomes if a certain standard is maintained. Juan Lourido 1 , Juman Rasheed 2 , Thooba Saeed 2 , Miuvaan Shujau 2 , Thihnan Solih 2 1 TreeTop Hospital, Neurosurgery, Hulhumale, Maldives , 2 TreeTop Hospital, Medicine, Hulhumale, Maldives 57 y/o female, conus intramedullary tumor biopsied and diagnosed of high grade astrocytoma. Developed encephalitic syndrome and Froin syndrome. Further treatment initially denied, underwent revision surgery for updated diagnosis and shunt. 56 y/o female, mid thoracic intramedullary tumor, targeted removal and biopsy as patient would not accept any risk, with secondary revision after confirmation of ependymoma of high grade. Case presentation of two patients treated for intramedullary malignant tumors of glial origin. Each one of them was managed respectively in a higher resources or a lower resources clinical setting (Surgical videos available). Challenges and implications, as well as lessons learned, are discussed regarding this type of operative procedures in different settings from different points of view: knowledge and skills, equipment and instruments, disposables, internal assets and coordination, external coordination, postoperative management, auxiliary diagnostics. Angela Carrascosa 1 , Juan Castaño Montoya 1 , Rebeca Perez Alfayate 1 , Pedro Alonso 1 1 Hospital Clinico San Carlos, Madrid, Spain Introduction: Ewing sarcoma (ES) is a malignant neoplasm that primarily involves extremity long bones, the pelvis, and soft tissues of children. ES represents 33% of primary bone tumors in young patients, and affects more men than women (1.5:1). The prevalence of Ewing vertebral sarcoma is approximately 3.5%, with the highest prevalence occurring in the sacral region (55%). Few cases of primary intradural extramedullary Ewing's sarcoma have been reported. We present 1 case of ES of the cervicodorsal spine managed with combined surgical approach and its evolution. To our knowledge, there is a case report of 34 cases of Edwing vertebral Sarcoma. Material and Methods: A 33-year-old male presented with cervical pain, severe quadriparesis, altered sensitivity and sphincter involvement in the last 2 days. Both motor and sensory disturbances were revealed on both legs at the clinical examination. The cervical MRI revealed a large cervicodorsal tumor that invades both the anterior and posterior spinal canal. It extends from C7 to the pulmonary apex without infiltrating it, medially invades the C7-D1 and D1-D2 conjunction foramina with their expansion, and invasion towards the spinal canal with marked spinal cord compression. Results: C7-D1 laminectomy was performed urgently with resection of the posterior tumor lesion and C6-D2 fixation. For the resection of the anterior cervical mass with right C7D1 foraminal invasion, a right supraclavicular approach was performed, completely resecting the tumor without the need for sternotomy. The pathological diagnosis confirmed SE, so the patient underwent systemic chemotherapy and local radiotherapy. PET CT did not show distant disease. The patient recovered strength in his lower limbs and left arm completely and in his right arm 4-/5. Imaging studies show complete tumor resection and the patient is independent. Conclusion: Intradural extramedullary Ewing sarcoma is extremely rare and therefore not usually considered when evaluating lesions of this region. These are highly malignant tumors and require intensive chemotherapy and radiation therapy after surgical resection. The prognosis is poor overall with frequent local recurrence and distant metastasis. Close follow up is therefore an essential component of management. The supraclavicular approach allows resection of tumor lesions in the upper cervicodorsal region without the need to perform a sternotomy, which increases morbidity in these patients. It is essential to perform a preoperative study of the anatomy in all the sections of the imaging tests, evaluating the relationship of the lesion with vascular and visceral structures and the pulmonary apex. The spinal resection and reconstruction followed by adjuvant treatment reduce the risk of local recurrence, and improve long-term survival. Georgios Zilidis 1 , Clare Jacobs 2 , Gerard Mawhinney 3 , Jeremy Reynolds 4 , Yaron Berkowitz 5 , Emma Kenney-Herbert 2 , Ather Siddiqi 6 , James Teh 7 , Basavaraj Chari 7 , Martin Gillies 8 , Tim Mccormick 9 , Ami Sabharwal 2 , Stana Bojanic 10 , Hayley Jones 2 , Alex Anderson 11 , Claire Worrall 11 , Niamh Louwman 11 , Harriet Dent 12 , Mariam Latif 9 , Tomasz Bajorek 13 , Mehrunisha Suleman 14 , Victoria Bradley 12 , Nicolas Beresford-Cleary 1 1 Oxford University Hospitals, Oxford Spinal Surgery Unit, OxMINT, Oxford, United Kingdom , 2 Oxford University Hospitals, Department of Clinical Oncology, Churchill Hospital, OxMINT, Oxford, United Kingdom , 3 Oxford University Hospitals, Oxford Spinal Surgery Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom , 4 Oxford University Hospitals, Oxford Spinal Surgery Unit, Oxford, United Kingdom , 5 Oxford University Hospitals, Department of Radiology, Experimental Medicine Division, Nuffield Department of Experimental Medicine, University of Oxford, Oxford, United Kingdom , 6 University of Oxford, Orthopaedic Oncology and Arthroplasty, Oxford, United Kingdom , 7 Oxford University Hospitals, Department of Musculoskeletal Radiology, Oxford, United Kingdom , 8 University of Oxford, Neurosurgery, Oxford, United Kingdom , 9 Oxford University Hospitals, Department of Anaesthesiology, Oxford, United Kingdom , 10 Oxford University Hospitals, Department of Neurosurgery, Oxford, United Kingdom , 11 Oxford University Hospitals, Department of Palliative Medicine, Oxford, United Kingdom , 12 Oxford University Hospitals, Department of Palliative Medicine, OxMINT, Oxford, United Kingdom , 13 Oxford University Hospitals, Department of Psychiatry, Oxford, United Kingdom , 14 University of Oxford, Medical Ethics and Law, Oxford, United Kingdom Introduction: The OxMINT MDT is a novel collaboration between a broad group of specialties including Neurosurgery, Spine Surgery, Orthopaedic Surgery, Interventional Radiology, Interventional Pain, Clinical Oncology, Palliative Medicine and Psychological Medicine. The group meet weekly to discuss clinical cases and to plan potential treatment options. This appears to be a novel collaborative we can find no model for elsewhere in the UK or globally, and has a particular focus on symptomatic management which is highlighted by the chair being held by Palliative Medicine. It is currently not job planned and thus functions as a special interest forum with all staff who have joined offering their time because they’re invested in the concept and believe it is the right service development to support. Staff have often been asked to join by current members and have been invited due to their proactive and positive approach to patient care and service delivery. Materials and Methods: We will describe a pilot ethnographic study to explore how collaborative decision making occurs in a multi-specialty MDT setting in the NHS. Observation of the OxMINT weekly MDTs is being undertaken to try to best understand the strengths and weaknesses of the current model. Additionally focus groups or interviews with key members will be undertaken if useful to add additional information. Results: The descriptive results of this study will be presented: 1. Understanding how interpersonal dynamics inform decision making in the context of a team that forms regularly but only for the purpose of clinical decision making and draws from a variety of medical specialties with their own innate cultures and perceptions. This team is formed in an informal manner offering a unique opportunity to explore decision making in a relatively unusual setting for healthcare. Does friendship improve frank exchange or limit truthful speaking? Does informality encourage debate or lead to blind spots? 2. Understanding how hierarchies influence decision making in the context of a team made up of specialties who tend to offer an innate deference to particular fields e.g. surgical decision-making taking preference over less interventional fields due to both healthcare dynamics and the prioritisation of the potential for cure in medicine. Does a waterfall effect down the specialties ensure that appropriate consideration is always given to key options, or is it reductive and limit creative approaches? 3. Understanding how decision making around intervention can be perceived to be truly shared in the context of a team where only certain individuals undertake those said interventions and thus traditionally hold total responsibility for them. Does group buy-in reduce the pressure felt by a surgeon or is it at best tokenistic? Conclusion: We aim to present the key ethnographic descriptors of a novel multi-disciplinary team focused around group decision making, in the hope these elements will be translatable to other settings. Our aspiration is to then broaden the study to look at other meetings including spinal surgeons including the Oxford Spinal Service Complex Case MDT and the Spine Oncology Meeting to compare and contrast culture and styles. Valerija Teodosic 1,2 , Milos Vasic 1 , Uros Novakovic 1,2 , Milos Mladenovic 1 , Ivan Tulić 1,2 , Slavisa Zagorac 1,2 1 University Clinical Center of Serbia, Clinic of Orthopaedic Surgery and Traumatology, Department of Spine Surgery, Belgrade, Serbia , 2 Faculty of Medicine, University of Belgrade, Belgrade, Serbia Introduction:  Secondary metastases of the spinal column of different origins are much more common than primary tumors. Acute metastatic spinal cord compression with symptoms such as severe pain or neurological impairment is an emergency situation that requires multidisciplinary approach. However, there is still controversy about the appropriate timing of operative treatment. Material and methods: We searched multiple databases for studies involving adult patients who had symptomatic spinal metastasis with spinal cord compression who underwent early or late surgical decompression with or without fixation, and also studies involving adverse postoperative events, for past ten years. Results: We analyzed eight studies who had met inclusion criteria, with 588 patients involving, and discovered that patients who underwent urgent surgical decompression (within 24 or 48 hours) and those who underwent late surgical decompression (after 48 hours) had similar rate of neurological improvement, but patients who underwent urgent decompression had lower complications rate than those who underwent surgical decompression after 48 hours, respectively. Conclusion: Our study shows that, despite of each patient must be approached individually and a decision about a timely operation must be made on the basis of a multidisciplinary approach, a 48h window seems to be the most beneficial and also the safest for patients with symptomatic spinal metastases. Keywords: Spinal metastases, Timely surgery, Early decompression Bahri Farah 1 , Ghassen Gader 1 , Wièm Mansour 1 , Hdhili Houssem 1 , Aziz Bedioui 1 , Mohamed Zouaghi 1 , Mouna Rkhami 1 , Mohamed Badri 1 , Kamel Bahri 1 , Zammel Ihsen 1 1 Trauma and Burns Center, Department of Neurosurgery, Ben Arous, Tunisia Introduction: Spinal dermoid cysts are rare congenital lesions that can present significant diagnostic challenges, particularly when infected. While typical cases are often diagnosed using MRI, infected dermoid cysts can present with ambiguous clinical symptoms and nonspecific radiological features, misleading the diagnosis. Materials and Methods: We report the case of a 14-month-old boy with a previously normal psychomotor development. Over the course of one week, the child exhibited a rapid onset of febrile torticollis and regression in motor skills. Initial diagnosis suggested bacterial meningitis caused by E. coli. However, the onset of paraplegia motivated lumbar MRI, which revealed an extensive intradural collection extending from L1 to S2. The child underwent urgent surgery, during which intraoperative findings included the presence of hair and sebaceous material within the dural sac at the L4 and L5 levels. Histopathological examination of the resected tissue confirmed a dermoid cyst with acute inflammatory changes and suppuration. Following the surgery, the patient regained his motor function quickly. Discussion: Spinal dermoid cysts are rare, benign pseudotumors that develop from an ectodermal inclusion early in embryonic development and account for less than 1% of spinal tumors. These cysts are usually found in the lumbosacral and sacrococcygeal regions and often present with symptoms of cauda equina syndrome. Infection of dermoid cysts is uncommon but presents significant diagnostic problems. When infected, these cysts can simulate bacterial meningitis, manifesting as fever and meningeal signs that can overshadow motor symptoms. MRI is essential for diagnosis, typically showing distinctive features. Surgical treatment involves aspiration of the cyst contents, but complete removal of the cyst capsule is often difficult due to its adherences to surrounding tissues. Incomplete resection can lead to complications, including adhesive arachnoiditis. Despite mostly positive surgical results, the presence of infection can worsen the prognosis and complicate healing. Accurate diagnosis and skillful surgery are therefore essential for effective management. Conclusion: Spinal dermoid cysts are rare benign lesions, mainly diagnosed by MRI. Infected cysts can mimic bacterial meningitis, clouding the clinical picture. Effective management requires accurate imaging to identify the characteristics of the cyst and careful surgical intervention to meet the challenges of complete resection. Despite generally positive surgical outcomes, complications related to infection highlight the need for thorough diagnostic and therapeutic approaches to optimize patient recovery and prognosis. Emre Yilmaz 1,2,3 , Thomas O'Lynnger 2 , Sandra Vermuelen 4 , Christian Fisahn 1,2,3 , Sarah Strot 2 , Marc Moisi 5 , Basem Ishak 1,2 , Joseph R. Dettori 6 , Clifford Pierre 1,2 , Luke Jouppi 1,2 , Rod Oskouian 1,2 , Jens Chapman 1,2 1 Seattle Science Foundation, Seattle, United States, 2 Swedish Neuroscience Institute, Seattle, United States, 3 Ruhr University Bochum, BG University Hospital Bergmannsheil, Department of General and Trauma Surgery, Bochum, Germany, 4 Swedish Radiosurgery Center, Seattle, United States, 5 Hurley Medical Center, Department of Neurosurgery, Fenton, United States, 6 Spectrum Research Consulting, Tacoma, United States Introduction: Primary incidental spinal schwannomas, neurofibromas, and meningiomas are typically treated with surgical resection. Few studies have examined the effects of radiosurgery as the primary treatment of spinal benign tumors. The aim of this study was to evaluate the efficacy of radiosurgery as a primary treatment option for this pathology. Methods: In this retrospective single-center study, the authors included all patients who were treated for spinal schwannomas, neurofibromas, and meningiomas with either radiosurgery or operative intervention from 2006 to 2016. Data points recorded include age, sex, BMI, smoking, immunosupression status, neurological exam, functional scores, radiographic follow-up data, recurrence and treatment, medical comorbidities, and margins of resection. Results: A total of 17 patients (14 females/ 3 males) underwent radiosurgery with a mean age of 54.8 ± 12.4 years. 39 patients (15 females/24 males) with a mean age 49.7 ± 15.5 years underwent surgical resection. 13 out of 17 radiosurgical patients had an unchanged tumor size after treatment. There was no significant difference in preoperative symptoms, including motor weakness, sensory loss, pain or the preoperative tumor volume. Comparing both groups, there was no difference in pain improvement, neurological symptoms, readmission or reoperation rate. Conclusions: Radiosurgery is a feasible and safe primary treatment for spinal schwannomas. Surgical resection was superior in decreasing the tumor volume, however, there was no significant difference in the postoperative pain scores, improvement in neurological symptoms, occurrence of adverse effects, or the rate of readmission and reoperation between both groups. Fabio Cofano 1 , Giuseppe Di Perna 2 , Bianca Baldassarre 2 , Flavio Panico 1 , Marco Ajello 1 , Nicola Marengo 1 , Fulvio Tartara 3 , Francesco Zenga 1 , Diego Garbossa 1 1 AOU Città della Salute e della Scienza Torino, Turin, Italy , 2 Policlinico Riuniti di Foggia, Foggia, Italy , 3 Humanitas Gradenigo, Turin, Italy Introduction: The impact of neurological deficits plays a role of inestimable importance in patients with a neoplastic disease. The role of surgery for the management of symptomatic spinal cord compression (SSCC) cannot be overemphasized, as surgery represents often the first and paramount step in patients presenting with motor deficits. The traditional paradigm of simple bilateral laminectomy for the treatment of spinal cord compression has been reviewed. The need to achieve a proper circumferential decompression of the spinal sac has been progressively highlighted in combination with the development of the more comprehensive and multidisciplinary concept of separation surgery. Material and Methods: This is a retrospective observational study investigating symptomatic patients that underwent surgical treatment for spinal metastases at author's Institutions from January 2010 to June 2019. Data recorded concerned patient demographics, tumor histology, peri -operative and follow-up neurological status (ASIA), ambulation ability, stability (SINS), grade (ESCC) and source of epidural compression and type of decompression (anterior/anterior-lateral (AD); posterior/posterior-lateral (PD/PDL); circumferential (CD). Results: A total number of 84 patients was included. AD/CD patients showed higher chance of neurological improvement and reduced rates of worsening compared to PD/PLD group (94.1%/100% vs 60.4%; 11.8% vs 45.8% respectively). Univariate logistic regression identified immediate post-operative improvement to be a significative protective factor for worsening at last follow-up. Stratifying patients for site of compression and considering anterior and circumferential groups, immediate post-operative neurological improvement, was mostly associated with AD and CD (p 0.011 and 0.025 respectively). Walking at last follow up was influenced by post-operative maintenance of ambulation (p 0.001). Conclusion: The necessity to remove the epidural metastatic compression from its source should be considered of paramount importance. Since the majority of spinal cord compression involves firstly the ventral part of the sac, CD/AD are associated with better neurological outcomes and should be achieved in case of circumferential or anterior/anterolateral compression. Majdi Ben Romdhane 1 , Ben Theyer Maher 1 , Bedoui Mootez 1 , Majdi Sghaier 1 , Tejouri Achref 1 1 Internal Security Hospital, La Marsa, Tunisia Introduction: Primary hyperparathyroidism is a rare condition. We present a case where hyperparathyroidism was identified through a pathologic fracture of the D11 vertebra, an unusual presentation. Materials and Methods: A 30-year-old woman with no prior medical history presented with isolated low back pain following a minor trauma, which persisted for one year. Clinical examination revealed localized tenderness over the dorsal-lumbar spinous processes without radiation or signs of disc-radicular conflict. Neurological examination was unremarkable. Imaging showed vertebral collapse of D11, suspected of malignancy, with lytic lesions confirmed on CT scan. MRI suggested a diagnosis of Langerhans cell histiocytosis or malignant hematopathy. The radiographic and CT scan findings indicated subperiosteal bone resorption with granular osteoporosis of the skull and multiple lytic bone lesions, raising suspicion of primary hyperparathyroidism. MRI revealed vertebral body collapse with extension of the lesion into the canal. Results: Elevated parathyroid hormone levels were observed without hypercalcemia. Scintigraphy showed hyperfixation in all four parathyroid glands, and ultrasound identified a parathyroid adenoma. After excluding secondary hyperparathyroidism, a diagnosis of normocalcemic primary hyperparathyroidism was confirmed. The patient showed good clinical progress under medical treatment, with near-complete resolution of bone metastases. Conclusion: We report a rare case of primary hyperparathyroidism revealed by bone involvement. This pathology should be considered in the differential diagnosis of bone matrix disorders suggestive of acquired osteodystrophy. Rukhsar Hussain 1 , Priyanshu Saha 1 , Charles Taylor 1 , Zion Hwang 1 , Adnan Sheikh 1 , Hasan Raza 1 , Liam Rose 1 , James Geddes 1 , Jason Bernard 1 , Timothy Bishop 1 , Darren Lui 1 1 St George's University Hospitals NHS Foundation Trust, Department of Orthopedic and Spinal Surgery, London, United Kingdom Introduction: In the past few decades, there has been a significant improvement in management of breast cancer through the use of genetics leading to further improvements in prognosis. Current systemic anti-cancer therapy continues to advance. Surgery for breast related MSCC should therefore be part of the surgical armamentarium. Palliative surgery to preserve ambulation and continence is important but even more so, those with oligometastatic disease should be considered for radical oncological surgery. Materials and Methods: This study reviewed 2514 patients with MSCC discussed at a spinal oncology meeting at a quaternary hospital in London from 2017 to 2023. Data collected included patient demographics, type of surgery, surgical approach, complications, ICU and hospital stay duration, Tokuhashi scores, CCI scores, and Frankel scores. For non-operative cases, data on chemotherapy or radiotherapy treatments were gathered. Statistical analyses were conducted to evaluate the impact of these factors on patient prognosis and outcomes. Results: Out of the 147 breast cancer patients, 39 underwent surgery, with the most common age for surgery being between 40-50 years. More than 95% of the sample were female. The lowest Charleston Comorbidity Index (CCI) score was 2, with majority of patients scoring higher suggesting a less than 5% estimated 10-year survival. The CCI score of 12 had a mortality of less than 1 year. Out of the 147 patients, 4 died within 30 days of admission. The Tokuhashi score for non-operative patients was a minimum of 5 due to the primary breast cancer, whilst the highest Tokuhashi score was 14 implying a less than 6-month prognosis. The Frankel score showed improvement in neurological deficits post-surgery with 3 patients having a rise to Frankel E scores (no neurological deficit) and 5 less patients had incomplete neurological deficit. Conclusion: Breast cancer represents a large percentage of MSCC at our hospital. Despite improving prognosis for patients the number of operative cases only represented 33.8% of breast MSCC cases. Overall, operative patients have better prognosis the younger they were due to few co-morbidities. The Frankel score has showed how surgical management has had a significant positive impact on patients as scores rose post-surgery (as neurological deficit improved). This research begins to highlight the benefits of these scoring systems, thus expanding research into different cancer types and patients from different demographics may help to increase the representativeness of this research. Yasemin Keith 1 , Priyanshu Saha 1 , Charles Taylor 1 , Zion Hwang 1 , Adnan Sheikh 1 , James Geddes 1 , Liam Rose 1 , Hasan Raza 1 , Jason Bernard 1 , Timothy Bishop 1 , Darren Lui 1 1 St George's University Hospitals NHS Foundation Trust, Department of Orthopedic and Spinal Surgery, London, United Kingdom Introduction: Gynaecological cancers comprise a significant proportion of female cancer cases. Despite advances in treatment, it is still associated with significant mortality. Metastatic spinal cord compression (MSCC) is a rare complication of gynaecological cancer. This paper aims to assess factors affecting outcomes in MSCC from gynaecological cancers. Materials and Methods: This is a retrospective study of MSCC from gynaecological primary cancers, identified from a Spinal Oncology MDT from 2017 to 2023 (2,503 total MSCC cases). Cases of uterine, cervical, ovarian, vulval and vaginal cancer were included. Data collected included key patient demographics such as age, sex, primary tumour type, treatment type, Charlson Comorbidity scores, Tokuhashi scores, ECOG performance scores, Frankel scores, and clinical outcomes, including total survival time & 30-day mortality. Predicted prognoses determined by Tokuhashi scores were compared to actual clinical outcomes. Results: Identified 23 patients, 8 (34.8%) underwent surgery, and 15 (65.2%) did not. The mean age was 64 years, ranging from 47-81 years. Surgical patients were older than non-surgical patients, with mean ages of 67 and 62 respectively. Surgical patients also had better average ECOG performance scores and Frankel scores at presentation. Average survival was 47.5 months in those aged 40-49, compared to 10 months for those aged 80-89. Those scoring 0 points in the Charlson comorbidity score had greater survival (28.5 months) than those scoring 2 (18.5 months) or 3 (0 months). Cervical cancer was the most common cancer (43.5%). Vulval and vaginal cancers were less well-represented (4.35% each). The longest survival time was seen in vaginal cancer (77 months), and the shortest was uterine cancer (8.83 months). Mean survival time was 16.7 months for surgical patients, versus 28.9 months for non-surgical patients. 30-day mortality rates were 12.5% for surgical patients, and 0% for non-surgical patients. Patients scoring between 0-8 on the Tokuhashi score had an actual average survival of 24.2 months, whereas those scoring between 9-11 had an average survival of 26.1 months. Conclusion: Average survival time was longer in younger patients, and those with a lower Charlson comorbidity score. Surgical patients were younger, with better average ECOG performance scores and Frankel scores at presentation. Differences were also observed between survival times of different cancers – cases of uterine cancer MSCC had significantly shorter survival compared to others. However, the low prevalence of gynaecological MSCC in this cohort may have affected findings, particularly in the less common primary cancers. Surgical patients had lower mean survival time, and greater 30-day mortality, and more analysis is needed to explain this. There was some correlation between the revised Tokuhashi score and survival time, but this was not predictive of prognosis as they are rare, therefore they were not included separately in the Tokuhashi score, which in modern oncology is starting to show its age as a scoring system. Bahri Farah 1 , Ghassen Gader 1 , Nessrine Jemel 2 , Hdhili Houssem 1 , Wièm Mansour 1 , Aziz Bedioui 1 , Mohamed Zouaghi 1 , Mouna Rkhami 1 , Mohamed Badri 1 , Kamel Bahri 1 , Zammel Ihsen 1 1 Trauma and Burns Center, Department of Neurosurgery, Ben Arous, Tunisia , 2 CHUM, Department of Neurosurgery, Montréal, Canada Introduction: Meningiomas are among the most common primary tumors of the central nervous system. They are mainly intracranial tumors. They are characterized by the abnormal proliferation of arachnoid cells, resulting in lesions that are generally benign and extra-axial. Spinal meningiomas are rare, and are most often intradural and extramedullary. They may be solitary or multiple, the latter often associated with neurofibromatosis type 2. Clinically, spinal meningiomas cause progressive compression of the spinal cord, with the majority localized in the thoracic spine. Early diagnosis and surgical resection are essential to preserve functional autonomy, as these tumors can lead to significant neurological deficits. Materials and Methods: This study retrospectively analyzed 18 patients who underwent surgery for spinal meningiomas at the neurosurgery department of the Trauma and Burns Center, Ben Arous, from January 2014 to December 2020. The aim was to evaluate how epidemiological, clinical, topographical, surgical, and histological factors impact functional outcomes. The study focused on preoperative and postoperative evaluations using the modified Rankin Scale (mRS). Results: The average age of our patients was 60 years, with female predominance (89%). One patient had neurofibromatosis type 2. Clinical presentation was mainly represented by motor symptoms (94%), sensory disorders (88%), and genito-sphincteric disorders (83%). At the time of diagnosis, the majority of patients had lost their autonomy. The average preoperative mRS score was 3. MRI revealed tumors that are typically iso- to hypointense on T1-weighted images (WI) and iso- to hyperintense on T2-WI. Contrast enhancement was intense and homogeneous in most of our cases. All our patients underwent surgery. Posterior approach was performed in all cases, even in those where the lesion was strictly anterior. Adjuvant radiation therapy was proposed when resection was incomplete or in cases of recurrence. Postoperatively, 14 patients had an mRS score < 3 compared to only 6 preoperatively. At the last consultation, eleven patients had an mRS score of 1, with an average score of 1.8. Only one recurrence was noted after 5 years. Conclusions: Spinal meningiomas, although rare, represent significant problems due to their ability to cause neurological damage. They generally have a favorable prognosis, with high rates of recovery and low recurrence if completely resected. Early diagnosis using advanced imaging techniques and timely surgical intervention remains challenging but is essential for optimal results. Factors influencing neurological outcome include age, delay in treatment, preoperative functional status and tumor location. Continued research and advances in imaging and surgical methods will improve the management and treatment of spinal meningiomas, as well as patients' quality of life and long-term outcomes. Bahri Farah 1 , Ghassen Gader 1 , Aziz Bedioui 1 , Wièm Mansour 1 , Hdhili Houssem 1 , Mohamed Zouaghi 1 , Mouna Rkhami 1 , Mohamed Badri 1 , Kamel Bahri 1 , Zammel Ihsen 1 1 Trauma and Burns Center, Department of Neurosurgery, Ben Arous, Tunisia Introduction: Chordomas are rare malignant bone tumors that account for 1-4% of primary bone neoplasms, mainly located in the clivus and sacro-coccygeal region. Chordomas are among the most encountered lesions of the sacro-coccygeal region, representing up to 20%. These tumors are characterized by slow development, leading to delayed diagnosis. Our study focuses on the clinical and radiological features of sacral chordomas, as well as their therapeutic strategies and outcomes depending on the surgical approach. Material and Methods: We went through a retrospective study on eight patients operated on for sacral chordomas between January 2012 and December 2022 at the Trauma and Burn Center of Ben Arous. Results: The mean age for our patients was 46 years, with a slight male predominance. The most frequent complaint was pain, with sacralgia being the most frequent, followed by radiculopathy. Sensory and motor deficits were observed in half the cases generally associated to sphincter dysfunction or genital disorders. Imaging revealed large lytic lesions centered on the sacral foramina, often extending beyond the midline, with notable destruction of the sacral vertebrae. A combined approach was used for 2 patients, in whom complete resection was achieved. The remaining 6 patients underwent a strictly posterior approach, with complete resection achieved in 4 of these cases. Combined approach was associated with greater blood loss. Postoperative infection of the surgical site was the most common complication, occurring in 7 patients. Tumor recurrence occurred in 3 patients after a mean follow up of 36 months after surgery. They have all been reoperated via a strictly posterior approach. On follow up, we noticed that the combined approach did not demonstrate superiority over the posterior approach. The main prognostic factor seems to be the quality of resection, whatever the surgical approach was. Conclusions: Sacral chordomas are difficult to diagnose because of their slow progression and late onset of symptoms. Imaging is key to diagnosis, with MRI enabling detailed characterization of the tumor. Surgical treatment, consisting mainly on wide excision via a posterior or combined approach, remains the gold standard for a radical treatment. Complete surgical excision with tumor-free margins improves prognosis. Despite aggressive treatment efforts, the prognosis remains uncertain, as survival rates and functional outcomes are heavily influenced by the extent of the tumor resection and the risk of metastasis. Continuous monitoring and multimodal therapeutic approaches, including radiotherapy, are essential for the management of these complex tumors. Prabodh Kantiwal 1 1 All India Institute of Medical Sciences, Orthopaedics, Jodhpur, India Introduction: Sacral chordoma is a locally aggressive malignant tumour originating from ectopic notochordal cells. Due to the poor response to adjuvant therapy, complete tumour resection is the choice. We present our experience of the single posterior approach for wide local resection and reconstruction of SI joint with autologous fibular strut and posterior stabilisation with either spino-pelvic fixation or trans-iliac plating. Material and Methods: This study examines the clinical progression, surgical response, and outcomes of eight patients with sacrococcygeal chordoma. Diagnostic methods included lumbopelvic magnetic resonance imaging (MRI), metastatic work-up either with ‘radionuclide bone scan + contrast-enhanced computed tomography of thorax and abdomen’ or ‘positron emission tomography (PET) scan’, and image-guided core needle biopsy with pathological evaluation and staging. Nerve root involvement was evaluated using preoperative imaging (MRI), emphasising preserving bilateral S1 and S2 nerve roots whenever possible without compromising the resection margins. In the standard prone position, we initiated a vertical midline incision in the lumbosacral area, with the distal end situated above or up to the natal cleft. Results: Preoperative embolisation was performed on one patient with a huge neglected Sacro-coccygeal Chordoma in a post-poliosis residual paralysis patient in the left lower limb. At the same time, no patient underwent preoperative chemotherapy. One patient encountered a postsurgical minor wound complication. All the patients are recurrence-free during the latest two-year follow-up period. Conclusion: Performing sacrectomy for large or giant sacral tumours through a posterior approach is both feasible and safe, resulting in reduced morbidity and no significant change in overall survival. Sami Bahroun 1 , Masmoudi Zied 1 , Anis Bouaziz 1 , Mohamed Samih Kacem 1 , Mohamed Samir Daghfous 1 1 Kassab Hospital, Orthopaedic Department B, Tunis, Tunisia Introduction: Osteoid osteoma is a benign bone tumor. It accounts for about 10% of benign skeletal tumors, and typically occurs in long bones, mainly the proximal femur. Spinal localization is found in only 10% of cases. Material and Methods: We reviewed 12 patients, 6 males and 6 females, with an average age of 16 years and 3 months, all diagnosed with histologically confirmed spinal osteoid osteoma. They were operated on and followed up at the Kassab Orthopedic Institute. Back pain was the main symptom, associated with spinal stiffness and a scoliotic posture in seven cases. Structural scoliosis was found in 2 cases. Two patients had neurological deficit signs. The diagnosis was made on average 18 months after the onset of pain. A scintigraphy performed on 8 patients showed increased focal uptake at the nidus with low uptake in reactive zone peripherally. CT scans performed on 11 patients revealed the nidus in 9 cases. The osteoma was located in the posterior arch in 11 cases and in the vertebral body in one case. Surgical resection was performed for all patients. Three patients had bone grafts, and one patient underwent scoliosis instrumentation. Results: All patients experienced rapid pain relief, though two had a recurrence of symptoms, with one requiring revision surgery, which resulted in a good outcome. The spinal syndrome resolved on average 7 months after resection. Patients reviewed after an average follow-up of 5 years and 5 months were satisfied with the outcome, with complete pain relief and restored spinal alignment. One patient developed well-tolerated pseudarthrosis of the graft. Conclusion: Spinal osteoid osteoma is a rare condition. Diagnosis is often delayed and challenging. It should be considered in case of atypical back pain associated with stiffness or spinal deviation. Surgical resection allows for histological diagnosis and cure, but localization can be challenging. intraoperative CT-guidance can be very beneficial in these procedures. Vasanth Bharathidasan 1 , Nigil Palliyil 2 , Jim Vellara 2 1 Amrita School of Medicine, Kochi, India , 2 Amrita Institute of Medical Sciences, Kochi, India Introduction: Multiple myeloma (MM) is the second most common hematological malignancy and the most common primary malignancy of the adult spine. Though radiosensitive, the bone tumor may cause neurological impairment or spinal instability warranting surgical intervention prior to radiotherapy. This paper aims to present the epidemiology, surgical indications, and outcomes of 30 patients with multiple myeloma of the spine operated in a single center over 7 years. Secondarily, we analyzed the association between pre-operative serum albumin levels and post-operative length of hospital stay and complications in this study. Material and Methods: Surgical instability was the criteria for selection, which was done by analyzing the SIN scores of the patients. All the patients who underwent posterior instrumentation at our institution for multiple myeloma from January 2016 to July 2023 were screened, and 30 patients met the inclusion criteria for the study. Details regarding the patient's biodata, comorbidities, ASA class, functional status, level of surgery, post-operative complications, and mortality were analyzed. In addition, the patient's pre-operative serum albumin, serum creatinine, WBC count, and platelet count were also collected and analyzed with the post-operative length of stay. Results: In the 30 patients, 19 were male (63.33%) and 11 patients were female (36.67%). The average age of patients was 56.77 ± 10.07 years. 2 patients (6.67%) were classified as ASA class 1, 24 patients (80%) were ASA class 2, and 4 patients (13.33%) were ASA class 3. Pre-operatively, when assessed for functional status, 1 patient (3.33%) was independent, while 21 patients (70%) were partially dependent and 7 patients (23.33%) were completely dependent; one patient was not assessed. These patients had an average SIN score of 10.71 ± 1.72. 24 patients (80%) underwent open surgery, while 6 patients (20%) underwent MIS. The mean follow-up period for patients was 6.68 ± 7.28 months. 6 patients (20%) had unplanned readmissions within 6 months of the procedure. At the time of final follow-up, 1 patient (3.33%) expired, and 2 patients (6.67%) had undergone reoperation (1 excision of tumor and 1 posterior instrumentation). 20 patients (66.67%) were found to have normal serum albumin values, while 10 patients (33.33%) were hypoalbuminous pre-operatively; the mean serum albumin level was 3.87 ± 0.67. The average length of stay was 12.74 ± 8.99. No significant difference in length of hospitalization was seen for hypoalbuminous and normal patients and between patients with higher and lower SIN scores. There was a statistically significant difference in length of stay observed in older patients (> 55 years) (p = 0.044). Conclusion: In this 7-year study, we aim to report the outcomes and associated factors in multiple myeloma patients who underwent posterior instrumentation for spinal instability. We also found that there was no significant relation between pre-operative albumin and the length of hospitalization of the patient. Sofia Mavili 1 , Priyanshu Saha 1 , Charles Taylor 1 , Zion Hwang 1 , Adnan Sheikh 1 , Liam Rose 1 , James Geddes 1 , Hasan Raza 1 , Jason Bernard 1 , Timothy Bishop 1 , Darren Lui 1 1 St George's University Hospitals NHS Foundation Trust, Department of Orthopedic and Spinal Surgery, London, United Kingdom Introduction: Despite significant advances in lung cancer treatment, metastatic spinal cord compression (MSCC) secondary to lung cancer remains a complication with poor prognosis for patient survival and quality of life. Lung cancer prognosis has improved due to systemic anti-cancer therapy (SACT). The introduction of targeted therapy such as KRAS inhibitors targeting KRAS gene mutations in lung cancers have been improving disease prognosis and survival outcomes. With more patients surviving beyond five years and a growing proportion remaining disease-free due to recent advancements in pharmacotherapy, the role of radical surgery for MSCC, once considered too high-risk, is being re-evaluated as a viable option to further improve survival outcomes. It remains paramount to advance the longevity alongside the quality of life of patients. This retrospective audit aims to investigate the survival outcomes of lung cancer patients with MSCC who underwent surgical intervention and the use of SACTs in these patients. Material and Methods: A retrospective study was conducted on 131 lung cancer patients with MSCC from a database of 2500 patients between 2017-2024. Data were collected from electronic patient records, including patient age, sex, date of presentation, surgical details, Frankel score, site of cancer, number of vertebrae affected, metastases to major organs, number of extra spinal bone metastases, Charlson Comorbidity Index (CMI), survival duration, and preoperative and postoperative pharmacotherapy. The Tokuhashi scoring system was used to predict survival outcomes, with scores categorized into three groups: 0-8 ( 1 year survival). Results: 119 patients had Tokuhashi scores between 0-8, while 12 patients scored between 9-11. 40% of the patients had a survival greater than 2-fold the expected survival outcome. The Tokuhashi score accurately predicted 58.8% survival in patients with an expected survival of 12 months. The proportion of deceased patients was greater in surgical patients (76%) than the non-surgical (62%) group. Among 42 surgical patients, 27 received SACT post-operatively where average survival was 23 months whereas in the group without SACT post-operatively average survival was 22 months. Patients with lower Tokuhashi scores who were managed conservatively had poorer survival outcomes than patients in the surgical and non-surgical group who had received SACT. Conclusion: Overall surgical patients had lower Tokuhashi scores, indicating a worse prognosis compared to non-surgical patients pre-operatively. Those managed conservatively similarly had a lower Tokuhashi score and were less likely to survive beyond six months. Of patients who received surgical intervention survival outcomes were marginally greater alongside SACT. The results of this study suggest that SACT improves survival times in patients with MSCC whether they had surgery or not. Priyanshu Saha 1 , Charles Taylor 1 , Zion Hwang 1 , Adnan Sheikh 1 , Hasan Raza 1 , Liam Rose 1 , James Geddes 1 , Jason Bernard 1 , Timothy Bishop 1 , Darren Lui 1 1 St George's University Hospitals NHS Foundation Trust, Department of Orthopedic and Spinal Surgery, London, United Kingdom Introduction: Metastatic spinal cord compression (MSCC) is a significant complication in advanced prostate cancer, affecting approximately 19% of patients with spinal metastases. Prompt decision-making between surgical and conservative management is crucial to prevent long-term neurological deficits and spinal instability. Conservative treatments include radiotherapy, chemotherapy, and corticosteroids. This retrospective audit investigates the clinical parameters influencing management choices and outcomes in MSCC patients with prostate cancer, focusing on clinical scoring systems and survival rates. Material and Methods: This study retrospectively reviewed 398 patients with MSCC secondary to prostate cancer treated at St George’s Hospital from 2017 to 2023. Data were collected on patient demographics, type of surgery, surgical approach (anterior or posterior), surgical complications, Charlson Comorbidity (CC) scores, Frankel scores, and Tokuhashi scores. The primary outcomes assessed were survival time and neurological function, evaluated through clinical scoring systems. Results: Of the 398 patients, 52 (15%) underwent surgery, while 85% were managed conservatively. Surgical patients had higher Tokuhashi scores, indicating a better prognosis compared to non-surgical patients. Those managed conservatively had a lower Tokuhashi score and were less likely to survive beyond six months. As the Tokuhashi score increased, the difference in survival between surgical and non-surgical groups diminished, potentially due to recurrent or further inoperable metastases. The Frankel score, assessing motor and sensory function, showed that the majority of surgical patients experienced no post-operative neurological loss, with some regaining function they had lost pre-surgery. Conclusion: Surgical intervention in MSCC patients with prostate cancer is associated with better survival outcomes and preservation or restoration of neurological function. Higher Tokuhashi scores correlate with improved survival, regardless of the management approach, though the benefit is more pronounced in surgical patients. The audit highlights the need for comprehensive data collection and multi-center studies to validate these findings and improve patient management strategies. Further research should explore the impact of additional prognostic factors and alternative treatments for patients unsuitable for surgery. Junya Kusakabe 1 , Ko Hashimoto 1 , Takahiro Onoki 1 , Kenichiro Yahata 1 , Kohei Takahashi 1 , Toshimi Aizawa 1 1 Tohoku University Graduate School of Medicine, Orthopaedic Surgery, Sendai, Japan Introduction: A cancer survivor is a person who is in all stages of life from cancer recognition to death. As the number of cancer survivors has been increasing in recent years, their spinal surgeries are also estimated to be increasing. The purpose of this study was to identify the characteristics of cancer survivors who underwent spine surgery for pathologies other than skeletal related events of the cancer. Material and Methods: Out of a total of 226 patients (male:female = 123:103, mean age 55 years) who underwent spine surgery at Tohoku University Hospital between January 2021 and December 2023, those who had a history of cancer and underwent spine surgery for a disease other than metastatic spinal tumors were extracted. Cancer type, history and timing for cancer treatment, spinal disease to be operated on, surgical procedure, and preoperative general condition (American Society of Anesthesiologists Physical Status system classification: ASA-PS) were investigated retrospectively. Results: Twenty-four cancer survivors (male:female = 10:14, average age 63 years), accounting for 10.6% of 226 patients, underwent spine surgery for non-skeletal-related cancer events. The types of cancer were as follows: breast cancer in 6 cases, gastric cancer in 5 cases, renal cancer in 3 cases, and lung cancer, pediatric cancer, uterine cervical cancer, and hematologic malignancies in 2 cases each; thyroid cancer, skin cancer, colon cancer, and bladder cancer were observed in 1 case each. Twenty-five cases had prior cancer surgery, eight had prior chemotherapy and three had prior radiation therapy. The time from the start of cancer treatment to spinal surgery was less than five years in 5 cases, between five and 10 years in 17 cases, more than 10 years in 7 cases, and unknown in 2 cases. Spinal diseases included 17 patients with degenerative diseases (3 in the cervical spine, 3 in the thoracic spine, and 11 in the lumbar spine), 3 patients with spinal tumors, 1 patient with symptomatic scoliosis, 1 patient with epidural hematoma, and 2 patients with other conditions. Eight patients underwent spinal surgery with instrumentation and 16 patients underwent spinal surgery without instrumentation. ASA-PS 1-4 were classified in 1, 12, 10, and 1 patient, respectively. Discussion and Conclusion: The cancer types of survivors who underwent spine surgery were diverse, not only those with a generally good prognosis. The study included patients with a short cancer course, more than half of whom underwent surgery for degenerative disease of the spine, and about half of whom had an ASA-PS of 3 or higher. These results could be attributed to the aging of cancer survivors’ population. Also, spine surgeries for cancer survivors were performed regardless of cancer type, timing of cancer onset, or systemic complications which could attribute to longer survival of the cancer survivors because of recent advance in cancer treatment, and demands for better quality of life by cancer survivors. Marcel Castelo 1,2 , Johan Hurtado 1 1 Hospital Antonio Lorena, Department of Neurosurgery, Cusco, Peru , 2 Universidad Nacional San Antonio Abad del Cusco, Cusco, Peru Background: Spinal schwannomas are benign nerve sheath, intradural and extramedullary tumors within the spinal canal (70%). Nevertheless, intraosseous schwannomas, which are extremely rare especially in the lumbar spine (less than 0.5%), can set up as an extradural, fast growing and very aggressive mass that compresses dural sac and destroys vertebral body, facing very challenging on management for neurosurgeons and oncologists. Case Description: We present the case of a 52-year-old male patient with chronic progressive low back pain, sciatica and bilateral paresthesias; in relation to an intraosseous lytic lesion within the spinal canal and vertebral body of L5, which was previously irradiated in other institution without biopsy. Complete surgical excision by posterior approach (intraoperative monitoring) and instrumented stabilization, titanium mesh grafting and fusion was performed, with good clinical results. Histopathology results confirmed a World Health Organization grade III immature schwannoma. Unfortunately, 6 months after during oncotherapy a very invasive recurrence and behavior was achieved with rapid deterioration and metastases. Conclusions: Intracanal and intraosseous malignant schwannoma is an extremely rare tumor in lumbar spine (this is the seventh case reported), which can be handle with multidisciplinary approach including complex surgery; but it has a very poor prognosis in the short term due to a very fast-growing rate and aggressive behavior. So, it's advised to talk to patient and family for outcome expectations. Jose Dangond 1 , Diana Lopez 2 1 Hospital Serena del Mar / Clinica Campbell, Orthopedicts, Spine, Cartagena / Barranquilla, Colombia , 2 Hospital Serena del Mar, Orthopedicts, Spine, Cartagena, Colombia Introduction: Myelopathy, a spinal cord injury with devastating consequences, can lead to transient or permanent neurological deficits, depending on the severity and location of the injury. This condition results in a range of symptoms, including pain, paralysis, altered sensitivity, and incontinence, often leaving the patient dependent on caregivers and external aids, confined to a wheelchair or bed. The etiologies of myelopathy are diverse, with the majority attributed to either traumatic or degenerative causes. Traumatic injuries, often due to compression or spinal cord trauma, are the predominant cause in individuals under 45 years of age, frequently resulting from traffic accidents. In contrast, patients over 45 typically experience atraumatic, degenerative injuries, commonly caused by falls. Myelopathy can also arise from various other underlying conditions, such as primary infections of the nervous system, neurosyphilis, head injury, neoplasms, cerebral abscesses, and tuberculomas. Spinal cord infarctions, although rare, have also been reported as a potential cause, as exemplified by the case of a teenage girl who developed acute myelopathy following a mild trauma. Accurate diagnosis of myelopathy is crucial, as it relies on a combination of clinical examination and complementary imaging studies, particularly magnetic resonance imaging. Electromyography can also be a valuable tool in the assessment of nerve root compression and anterior horn cell syndromes. Material and Methods: The case of a 36-year-old female patient with a diagnosis of breast cancer with metastasis to the thoracic spine is presented, who went to the emergency room of the Serena del Mar hospital due to paraplegia of the lower limbs after chemotherapy with subsequent loss of sensory and motor functions in lower limbs. Results: A case report is carried out and an extensive review of the literature, finding mainly reports and case series on this aggressive and devastating complication. Conclusion: Chemotherapy-induced myelopathy, although rare, is a serious complication that requires a high index of suspicion for diagnosis. Discontinuation of the causative agent and symptomatic management are essential to improve clinical outcomes. Research continues to identify more effective prevention and treatment strategies. Leon Cleres Penido Pinheiro 1 , Rodrigo Kei Kuromoto 1 , Walterney Amancio Filho 1 , Marlon Cesar Melo de Souza Filho 1 , Gustavo Lordelo 1 , Rodrigo Almeida Cunha 1 , Andrei Joaquim 1 , Eloy Rusafa Neto 1 , Osmar Jose Santos de Moraes 1 , Roger Schimidt Brock 1 1 Sao Paulo University, Sao Paulo, Brazil Background: The analysis of intradural spine lesions is fundamental to spine surgery. Understanding lesion histologic distribution is essential for refining treatment protocols and improving surgical outcomes. This study examines the variety of intradural lesions treated at a tertiary public hospital in Brazil. Methods: We retrospectively reviewed medical records of patients treated for intradural tumors from 2017 to 2024, focusing on histological diagnosis distribution. The histological findings were analysed separately for intradural extramedullary lesions and intramedullary lesions. Results: Among 118 patients treated, there were 77 cases of intradural extramedullary tumors and 41 intramedullary tumors. The histological breakdown was as follows: meningiomas (25.5%), schwannomas (30.4%), ependymomas (23.5%), astrocytomas (3.5%), neurofibromas (2.5%), arachnoid cysts (3.5%), intramedullary cavernomas (1.7%), lymphomas (1.7%), lipomas (1.7%) and hemangioblastomas (1.7%). Additionally, neuroendocrine tumors, and malignant undifferentiated lesions each constituted 0.9%. Conclusion: Meningiomas and schwannomas were the most prevalent intradural extramedullary lesions identified, followed by ependymomas as the most common intramedullary lesion. The presence of various rare lesions underscores their importance in the differential diagnosis of intradural spine lesions. Bilal Raza Slote 1 , Akbar Jaleel Jaleel 1 , Javeria Saeed 2 , Muhammad Ahsan Sulaiman 1 , Masood Umer 1 1 Aga Khan University Hospital, Section of Orthopedics, Department of Surgery, Karachi, Pakistan , 2 Aga Khan University Hospital, Department of Surgery, Karachi, Pakistan Introduction: Sacral tumors are rare, constituting a small percentage of primary bone and spinal tumors, and their treatment primarily involves complete surgical excision. This is a complex surgery which has risks of iatrogenic injury to surrounding structures, necessitating hyper-specialized teams, including colorectal, gynecological, urological, and plastic surgeons, alongside orthopedic and spine tumor surgeons. Techniques like neuromonitoring and preoperative angioembolization help avoid or minimize complications, while minimally invasive robotic surgeries are being explored in developed countries. In resource-constrained countries, management is adapted to available facilities. In our hospital where the study is being conducted, a multidisciplinary tumor board approach guides individualized patient care. This study reviews the outcomes of sacral tumor management at our tertiary health care center. Material and Methods: All cases between January 2017 to December 2022 who underwent surgical resection of sacral tumors at a single tertiary care center were studied. All the cases were extracted from ERC (ethical review committee) approved tumor registry. Demographics, tumor pathology, involvement of multiple surgical teams perioperatively were recorded and outcomes were studied. Results: During the study duration, a total of 13 sacral tumor cases were seen, out of which 8 underwent surgical resection. One of our patients had a metastatic sacral deposit which was solitary, hence excised. Five primary benign tumors and two primary malignant tumors constituted the list. As per tumor pathology, fifty percent of the cases (four out of eight) were giant cell tumors. Wound dehiscence was recorded in three patients and only one patient had motor deficits. Conclusion: Excision of sacral tumors is effectively performed in resource constrained regions. Multidisciplinary approach plays an important role in improved treatment outcomes. Angela Carrascosa 1 , Juan Castaño Montoya 1 , Javier Buendia 1 , Cristina Gomez 1 , Rebeca Perez Alfayate 1 , Pedro Alonso 1 1 Hospital Clinico San Carlos, Madrid, Spain Introduction: Chordomas account for 1% to 4% of primary tumors of the spine and sacrum. The mobile spine is affected in 10-15% of cases but chordomas are extremely rare in the cervical spine. Methods: 56-year-old woman with chronic cervicalgia who has been experiencing distal paresis in the left hand and neuropathic pain in C7C8 for 6 months. MRI shows a mass centered in the body of C6 measuring 5.5 x 3.5 x 7.6 cm with extension to the left prevertebral and carotid spaces and posterior extension encompassing the body of C7 and the C5-C7 foramina and invading the spinal canal anterolaterally. The mass displaces the carotid bundle and the left vertebral artery laterally until it enters the C5 foramen. The mass causes a 21% stenosis of the v1 and v2 segments. The intracanal component occupies 70% of the canal and causes severe spinal cord compression at C6, while it occupies 50% at C5C7. A needle biopsy revealed a conventional chordoma. Block resection is decided but the patient does not accept due to root sequelae. Results: A posterior approach was performed with fixation to lateral masses C3C4C5D1D2, laminectomy C5C6C7D1, resection of the lateral mass and pedicle of C5C6C7 on the left and C6 on the right with clear visualization of the radicular of C7C8 on the left, while C5C6 was surrounded and infiltrated by the tumor lesion. The lesion invades the dura mater at the anterolateral level at C5C6C7. In the second surgical stage, an anterior cervical and left supraclavicular approach is performed, supraclavicular dissection until the vertebral artery and left brachial plexus are visible, not invaded but compressed. The lower tumor plane is dissected in D1 without requiring pulmonary collapse or sternotomy. Corpectomy C5C6C7, tumor resection at the foraminal level from C4C5 to C7D1 connecting the posterior resection to the anterior one, preserving the roots. Infiltrated longus colli muscle is resected, preserving the cervical sympathetic chain with the stellate and middle ganglion. A vascularized fibular flap is placed from the anterior tibial artery to the superior thyroid artery and two venous drains to the anterior jugular vein. A 70 mm anterior cervical plate is placed with screws in C4 and D1. The cervical plate is covered with fatty tissue from the peroneal flap and fatty tissue posterior to the esophagus. The postoperative MRI showed only tumor remnants that included the roots previously infiltrated, so it was decided to perform treatment with proton therapy. After 1 year of follow-up, the root remains remained unchanged and the patient recovered the preoperative paresis after decompression. Conclusion: Spine chordoma, commonly located in the cervical and epidural region, is extremely rarely met. Their locally aggressive behavior typically prompts consideration of aggressive surgical resection. Bloc resection is the preferred surgical treatment for the management of chordomas. The use of pre- and/or post-operative photon image-guided radiotherapy, should be considered for the treatment of primary and recurrent chordomas in the mobile spine and sacrum, since these RT modalities may improve local control. Leon Cleres Penido Pinheiro 1 , Rodrigo Kei Kuromoto 1 , Marlon Cesar Melo de Souza Filho 1 , Walterney Amancio Filho 1 , Gustavo Lordelo 1 , Rodrigo Almeida Cunha 1 , Andrei Joaquim 1 , Eloy Rusafa Neto 1 , Osmar Jose Santos de Moraes 1 , Roger Schimidt Brock 1 1 Sao Paulo University, Sao Paulo, Brazil Background: Intradural spinal tumors are categorized into intradural extramedullary and intramedullary lesions, each differing significantly in histological origins, epidemiology, and treatment approaches. This study compares the epidemiological characteristics and outcomes of these two types of lesions. Methods: A retrospective analysis was conducted on patients with intradural spinal tumors treated at a tertiary hospital in São Paulo, Brazil, from 2017 to 2024. Data collected included patient demographics, presenting symptoms, tumor location, time from diagnosis to surgery, and pre- and post-operative functional status using the McCormick Scale and modified Rankin Scale. Results: The study found no significant differences in age and gender between the intradural extramedullary and intramedullary groups. Intramedullary lesions involved more spinal levels (p < 0.001) and had a longer time from diagnosis to surgery (p = 0.015). Functional outcomes were similar at baseline between the groups (McCormick Scale p = 0.07173; mRS p = 0.2267) but diverged significantly at discharge and during late follow-up, with intramedullary patients exhibiting worse outcomes (McCormick Scale p = 0.0063; mRS p < 0.001). Surgical approaches also differed, with complete laminectomies more frequent in intramedullary cases (82.8% vs. 34.5%) and hemilaminectomies more common in extramedullary cases (60.3% vs. 10.3%; p < 0.001). Conclusion: The site of tumor development and its histological type significantly influence treatment strategies and outcomes in patients with intradural spinal tumors. This study underscores the importance of understanding these differences to enhance patient care continually. Leon Cleres Penido Pinheiro 1 , Rodrigo Kei Kuromoto 1 , Marlon Cesar Melo de Souza Filho 1 , Matheus Yamaki 1 , Walterney Amancio Filho 1 , Gustavo Lordelo 1 , Rodrigo Almeida Cunha 1 , Andrei Joaquim 1 , Eloy Rusafa Neto 1 , Osmar Jose Santos de Moraes 1 , Roger Schimidt Brock 1 1 Sao Paulo University, Sao Paulo, Brazil Background: Intradural extramedullary tumors are lesions that develop inside the spinal canal but outside the spinal cord. The most common examples are schwannomas and meningiomas. These conditions can be challenging to treat, and the most important factors associated with recovery after surgery are still under discussion in the literature. This study aimed to understand the recovery of patients with intradural extramedullary tumors as a function of the time elapsed before surgical intervention. Methods: A retrospective analysis was conducted on patients with intradural extramedullary tumors treated at a tertiary hospital in São Paulo, Brazil, from 2017 to 2024. The values of the McCormick Scale (MCS) and modified Rankin Scale (mRS) were obtained before surgery and 12 months after surgery. The variation coefficient was calculated by subtracting the preoperative value from the 12-month postoperative value. The correlation between the time from clinical complaint to surgery (TCS) and the variation coefficient was analyzed using Spearman’s Rank Correlation. Results: A total of 77 patients underwent surgery for intradural extramedullary tumors. The average time from clinical complaint to surgery was 12.8 months. The correlation coefficient between the McCormick Scale variation coefficient and TCS was 0.65 (S = 9637.1, p < 0.001). The correlation coefficient between mRS variation and TCS was 0.70 (S = 8115.1, p < 0.001). Conclusion: There is a significant statistical association between the 1-year postoperative status and the time elapsed before receiving appropriate treatment. These results are relevant for prioritizing surgery for patients suffering from intradural extramedullary tumors. Priyanshu Saha 1 , Charles Taylor 1 , Zion Hwang 1 , Adnan Sheikh 1 , Liam Rose 1 , Hasan Raza 1 , Timothy Bishop 1 , Jason Bernard 1 , Darren Lui 1 1 St George's University Hospitals NHS Foundation Trust, Department of Orthopedic and Spinal Surgery, London, United Kingdom Introduction: Gastrointestinal (GI) cancers, particularly colorectal cancer can be effectively treated with surgery and systemic anti cancer therapy (SACT). However, metastatic spinal disease conveys a poor prognosis compared to other regions of metastases. This study aims to compare the characteristics and outcomes of surgical versus non-surgical management of MSCC in Lower GI cancer patients, particularly colorectal cancer. Materials and Methods: This retrospective study from a prospectively collected database of 2500 MSCC patients discussed in spinal oncology multidisciplinary team meetings from 2017 to 2023. Data were collected using iClip PowerChart, covering primary tumor location, symptoms at presentation, MDT decision date, surgery date, date of death, age at presentation, hospital and ICU stay duration, and survival time. Additional data on surgical techniques, complications, and perioperative treatments were recorded. Frankel scores, revised Tokuhashi scores, and Charlson Comorbidity Index scores were also analyzed. Statistical analyses were performed to compare surgical and non-surgical patient outcomes. Results: Out of 154 patients, 21 underwent surgery, while 75 received non-surgical management. Surgical patients had a mean ICU stay of 0.64 days and a mean hospital stay of 13.3 days, compared to 2.43 days for non-surgical patients, who did not require ICU care. The mean survival time was 6.35 months for surgical patients and 5.15 months for non-surgical patients. Surgical patients were younger, with a mean age of 61.9 years compared to 67.1 years in the general MSCC population. Colorectal cancer was the most common primary tumor, accounting for 54% of cases. Conclusion: Lower GI and colorectal disease only represent a small proportion of MSCC patients. The majority of cases are not deemed suitable for surgery with low Tokuhashi scores concordant with low Oncologist predicted survivorship. The procedure is mainly palliative to preserve ambulation and continence with surgery allowing a mean survivorship of 6 months. Kaike Eduardo da Silva Lobo 1 , Numa Rajab 2 , Yan Silva 3 1 State University of Pará, Belém, Brazil , 2 Sulaiman Al Rajhi University, Al Bukairyah, Saudi Arabia , 3 Hospital Ortopédico do Estado, Salvador, Brazil Introduction: Intradural extramedullary (IDEM) schwannomas are slow-growing tumors arising from the nerve sheaths in the spine. Standard treatment involves gross total resection, typically via laminectomy, although this has documented complications such as spinal instability and kyphosis. However, with a growing interest in minimally invasive procedures, hemilaminectomy has emerged as an effective alternative in approaching these tumors. To assess the efficacy and safety of both approaches, we conducted a meta-analysis comparing their outcomes. Material and Methods: We systematically searched PubMed, Embase, Cochrane Library, and Web of Science for randomized controlled trials and observational studies comparing laminectomy with hemilaminectomy for surgical resection of IDEM schwannoma. The outcomes assessed included length of hospital stay, intraoperative blood loss, operative time, Visual Analog Scale (VAS) scores, and postoperative complication rate. Mean difference (MD) and odds ratio (OR) were calculated for continuous and binary outcomes, respectively, with 95% confidence interval (CI). Results: Of 189 articles screened, a total of 3 studies were included, comprising 160 patients, of whom 79 (49.4%) underwent laminectomy and 81 (51.6%) received hemilaminectomy. Hemilaminectomy was not able to significantly reduce the length of hospital stay (MD 3.00; 95% CI -0.02, 6.01; p = 0.05; I 2 = 69%) and intraoperative blood loss (MD 79.44; 95% CI -126.56, 285.45; p = 0.45; I 2 = 67%) in comparison with laminectomy. However, hemilaminectomy was associated with a significantly decreased operative time (MD 66.83; 95% CI 27.56, 106.09; p = 0.0009; I 2 = 62%). Additionally, there was no significant difference between groups in VAS score (MD 1.00; 95% CI -1.06, 3.05; p = 0.34; I 2 = 94%) and complication rate (OR 4.21; 95% CI 0.85, 20.83; p = 0.08; I 2 = 0%). Conclusion: In this meta-analysis evaluating patients who underwent surgical resection of IDEM schwannoma, hemilaminectomy did not significantly reduce hospital stay or intraoperative blood loss compared to laminectomy, though it was associated with a significantly shorter operative time. No significant differences were observed between the two procedures in terms of pain or complication rate. Further research is needed to explore other potential benefits of hemilaminectomy and to better define its long-term outcomes in this patient population. Victor Cury 1,2 , Leonardo Simoes 1 1 NeuroSpine Group, Neurocirurgia, Rio de Janeiro, Brazil , 2 Instituto Estadual do Cérebro Paulo Niemeyer, Neurocirurgia, Rio de Janeiro Introduction: Vertebral hemangiomas (VHs) are the most common benign tumors of the spinal column and are often encountered incidentally during routine spinal imaging. VH are usually asymptomatic and, therefore, are commonly detected as accidental findings on spinal imaging on computed tomography (CT) and magnetic resonance (MR) imaging of the spine. When their imaging appearance is “typical” (coarsened vertical trabeculae on radiographic and CT images, hyperintensity on T1- and T2-weighted MR images), the radiological diagnosis is straightforward. Nonetheless, VHs mightalso display an “atypical” appearance on MR imaging because of their histological features (amount of fat, vessels, and interstitial edema). No treatment is indicated when they’re incidentally, nevertheless, some hemangiomas may clinically manifest axial pain and neurological deficit and require surgery or other treatment. Material and Methods: Review about the management of VHs in symptomatic cases whith filters included “vertebral hemangioma”, “symptomatic vertebral hemangiomas”, “radiology about vertebral hemangiomas”, and discussion about a case-report of a symptomatic woman and atypical radiology image. Results: I.R.S.B.P. 60y, came to neurosurgeon with back pain getting worst along two years, after a fall from heigh stated with radiculopathy in lower limbs, associated a dysesthesia. In MR with tumor infiltrative and expansive and contrast-enhancing lesion affecting the vertebral body, pedicles, right transverse process, posterior lamina, bilateral articular facets, right superior articular facet and spinous process of the first lumbar vertebra, with slight reduction in vertebral height, facilitated diffusion suggesting low cellularity , with extra-osseous soft tissue components that occupy the anterior and right posterolateral extra-dural intraspinal space at this level, stenosing the spinal canal and compressing the conus medullaris which has a faint hypersignal on STIR due to compressive myelopathy and insinuation of the right neural foramen D12-L1. The neurosurgical approach was then chosen to resect the lesion and compress the conus medullaris. Patient underwent arthrodesis from D11 to L3 with L1 corpectomy associated with laminectomy at the same level, with complete resection of the lesion. The postoperative period was carried out in an ICT, to follow hemodynamic surveillance, since due to the possibility of massive bleeding during surgical procedure and there may still be some degree of bleeding in the postoperative period, which happened mild form in case presented with loss of 2 points of hemoglobin in the postoperative period despite intra and postoperative red blood cell replacement, but with rapid stabilization. Neurlogical developed mild transient paresis in the right hallux, with complete improvement within 3 days. Then discharged with improvement in initial symptoms and good postoperative evolution with outpatient follow-up. Histopathological report reinforces the initial diagnosis of vertebral hemangioma. Post-operative thoracolumbar tomography showed complete resection and good results as scheduled pre-operatively. Conclusion: VM is a condition that usually has benign characteristics with an incidental asymptomatic finding, however in some cases, they present with an aggressive evolution, compressing the spinal canal and vertebral root at the level in question due to local bleeding or rapid growth, when we call it aggressive hemangioma. In this cases we should undergo surgical resection to control symptoms and block disease progression. Chan Hee Koh 1 , Constantinos Thoma 1 , Theofanis Giannis 1 , George Prezerakos 1 , Adrian Casey 1 1 National Hospital for Neurology and Neurosurgery, London, United Kingdom Introduction: Spinal cavernomas are vascular malformations that arise due to endothelial dysmorphogenesis from congenital lesions. Although cavernomas are often managed conservatively with clinical and radiological follow-up, there is a risk of intramedullary haemorrhage that can lead to significant morbidity. This study aims to delineate the natural history and surgical outcomes of spinal cavernomas as reported by patients. Material and Methods: An online 36-item survey was distributed via two cavernoma patient groups using their respective social media outlets. The length of follow up, management undertaken, extent of resection, and rebleed events were recorded. The rebleed survival rates were analysed using an interval censored survival analysis and Sun’s log-rank test. The expected value of postoperative changes in symptoms across time were analysed using a Bayesian multinomial mixed-effects regressions. Results: There were a total of 117 participants included in this study. 36/177 (24.8%) underwent surgical resection of their cavernoma, of which 29 were told they had a complete resection, and 81/177 (69.2%) underwent conservative management. Patients who underwent surgical management had a significantly greater 20-month survival rates (96.0%) compared to those who received surgical management (64.7%; p = 0.02). The 20-month survival rate for those with complete resection were 100%, in comparison to 83.3% for those who received incomplete resection (p = 0.46). In those who underwent surgical resection of their cavernoma, the symptoms were on worse on average in the immediate postoperative period, although these has resolved to at lease baseline between 3-months and 60-months (p < 0.03). However, around 30% of patients continued to report worsened symptoms compared to their preoperative baseline. Conclusions: Surveying social media based patient participation groups has the potential to amplify data in rare pathologies. The survival rates of patients undergoing surgical resection of the spinal cavernomas in this cohort were significantly higher than those managed conservatively. Although the symptoms after surgical management were on average the same or better, a significant minority reported worsened symptoms after.

Yasutsugu Yukawa 1 , Takuhei Kozaki 2 , Fumihiko Kato 1 , Hiroshi Yamada 2 1 Nagoya Kyoritsu Hospital, Spine Center, Nagoya, Japan , 2 Wakayama Medical University, Orthopedic, Wakayama, Japan Introduction: Increased signal intensity (ISI) is usually recognized at the disc level of the responsible lesion in the patients with cervical myelopathy. However, it is occasionally seen at the vertebral body level, below the level of compression. We aimed to investigate the clinical significance and the radiographic characteristics of ISI at the vertebral body level. Material and Methods: This retrospective study included 135 patients with cervical spondylotic myelopathy who underwent surgery and with local ISI. We measured the local and C2-7 angle at flexion, neutral, and extension. We also evaluated the local range of motion (ROM) and C2-7 ROM. The patients were classified into group D (ISI at disc level) and group B (ISI at vertebral body level). Results: The prevalence was 80.7% (109/135) and 19.3% (26/135) for groups D and B, respectively. Local angle at flexion and neutral were more kyphotic in group B than in group D. The local ROM was larger in group B than in group D. Moreover, C2-7 angle at flexion, neutral and extension were more kyphotic in group B than in group D. There was no significant difference of clinical outcomes 2 years postoperatively between both groups. Conclusion: Group B was associated with the kyphotic alignment and local greater ROM, compared to group D. As the spinal cord is withdrawn in flexion, the ISI lesion at vertebral body might be displaced towards the disc level, which impacted by the anterior components of the vertebrae. This should be different from the conventionally held pincer-mechanism concept. Benno Bullert 1,2 , Jula Gierse 1,2 , Paul Alfred Grützner 1,2 , Sven Vetter 1,2 1 BG Trauma Center Ludwigshafen, Ludwigshafen, Germany , 2 University of Heidelberg, Heidelberg, Germany Introduction: Lateral lumbar interbody fusion (LLIF) for ventral stabilization of the spine has become very popular in recent years. This approach has advantages in terms of blood loss, hospitalization time and costs [1]. The rise of minimally invasive approaches in spinal surgery has led to an increase in the radiation exposure of the OR team and the patient due to intraoperative imaging [2]. The use of ultra-low radiation combined with image enhancement software (enhanced fluoroscopy) can reduce radiation exposure. The aim of this study is to compare the radiation exposure of the OR team and the patient between enhanced fluoroscopy and conventional fluoroscopy in LLIF surgery. Material and Methods: The study is a single-center prospective randomized trial from in a Level-1 Trauma Center. All patients since 03/2023 who have had a ventral fusion of the spine using a lateral approach at levels Th10 to L5 and consented to the study were included. They were then randomized to one of the two groups (enhanced fluoroscopy (eFluoro) vs. conventional fluoroscopy (cFluoro)). The radiation exposure of the operating room staff was recorded using live dosimeters. The patient’s radiation exposure was assessed by analyzing the C-arm’s dose report. Normal distributed data were analyzed using an unpaired t-test, non-normal distributed data were analyzed using the Mann-Whitney U-test. Results: A total of n = 30 patients have been included in the study to date, of which n = 28 were included in the analysis (eFluoro n = 14, cFluoro n = 14). Two eFluoro cases were excluded as they were switched to cFluoro because the OR staff were not sufficiently trained in the use of the image enhancement software. The radiation exposure of the OR staff was significantly lower when using eFluoro compared to cFluoro (surgeon: 14.23 µSv vs. 43.00 µSv, p < 0.001; assistant: 3.31 µSv vs. 15.90 µSv, p < 0.001; scrub nurse: 1.74 µSv vs. 4.60 µSv, p = 0.004). There was no significant difference in the duration of surgery (p = 0.674), the number of X-rays (p = 0.113) and the fluoroscopy time (p = 0.114). The reduction in patient radiation exposure based on the DAP was also not significant (4272.51 mGy*cm 2 vs. 7889.74 mGy*cm 2 , p = 0.081). Conclusion: This preliminary analysis shows that the use of ultra-low radiation combined with image enhancement software (enhanced fluoroscopy) significantly reduces the radiation exposure for the OR team. The patient's radiation exposure also shows a recognizable trend towards a radiation reduction, although this is not yet significant, presumably because the number of cases is limited. References 1. Xu DS, Walker CT, Godzik J, Turner JD, Smith W, Uribe JS: Minimally invasive anterior, lateral, and oblique lumbar interbody fusion: a literature review. Ann Transl Med 2018, 6 (6):104. 2. Yu E, Khan SN: Does Less Invasive Spine Surgery Result in Increased Radiation Exposure? A Systematic Review. Clinical Orthopaedics and Related Research® 2014, 472 (6):1738-1748. Adnene Benammou 1,2 , Habib Sanaa 1,2 , Cherif Kamoun 1,2 , Souha Bennour 1,2 , Yasmine Ben Abdeladhim 1,3 , Mehdi Bellil 1,2 , Mohamed Ben Salah 1,2 1 University Tunis el Manar, Faculty of Medecine of Tunis, Tunis, Tunisia , 2 Charles Nicolle Hospital, Orthopedic Surgery Department, Tunis, Tunisia , 3 Charles Nicolle Hospital, Radiology Department, Tunis, Tunisia Introduction: The iliolumbar vein most commonly arises from the common iliac vein and drains the fourth and fifth lumbar vertebrae and the iliac and psoas muscles. These veins are encountered during the anterior approach to the lower lumbar spine. They are characterized by significant anatomical variability and vulnerability during surgery, which can lead to massive and potentially fatal intraoperative bleeding. To avoid these complications, a thorough knowledge of vascular anatomy is essential, hence the interest of our study, which aims to investigate the anatomical characteristics of the iliolumbar vein in the Tunisian population. Material and Methods: This is a descriptive study involving 30 patient who had an abdominal angio CT-scan, collected from the radiology department of Charles Nicolle Hospital. Results: Our study included 30 patients. The average age was 52 years with a sex ratio of 2. The level of aortic bifurcation was located at L4 in 44% of cases, L3-L4 in 28% of cases, and L4-L5 in 22% of cases. The level of iliocaval confluence was located at L4-L5 in 28% of cases and at L5 in 56% of cases. The iliolumbar vein was present in 78% of cases, unilateral in 11% of cases, and bilateral in 67% of cases. The angle between the iliolumbar vein and the left primitive iliac vein averaged 101°. The distance between the termination of the iliolumbar vein and the confluence of the two primitive iliac veins averaged 60 mm. The Vascular windows L4-L5 which correspond to the distance between the lateral border of L4-L5 and the edge of the iliocaval vein averaged 26 mm. Conclusion: The knowledge of the morphometric parameters of the iliolumbar vein is vital for determining surgical approach, risk of avulsion, and for identifying it for ligation during the exposure phase. CT scans are essential for preoperative planning, especially in the case of L3-L4 and L4-L5 ALIFs. In fact, it enables us to study the vascular anatomy and avoid complications that could be fatal for the patient. However, are these CT results really correlated with those found intraoperatively Despite the difference in the patient's position, which may be responsible for modifying anatomical landmarks? Josephine Coury 1 , Fthimnir Hassan 1 , Nathan Lee 2 , Steven Roth 3 , Thomas Zervos 1 , Chun Wai Hung 4 , Michael Vitale 1 , Benjamin Roye 1 , Zeeshan Sardar 1 , Joseph Lombardi 1 , Ronald A. Lehman 1 , Lawrence Lenke 1 1 Columbia University Irving Medical Center, New York, United States , 2 Midwest Orthopaedics at RUSH, Chicago, United States , 3 University of Florida Medical Center, Gainesville, United States , 4 Houston Methodist, Houston, United States Introduction: MRI-based spinal cord shape type estimates the risk of intraoperative neuromonitoring data loss in spinal deformity surgery. Cord shape types I, II, and III (TI, TII, TIII) are identified from axial MRI based on cord shape and CSF presence at the deformity apex. Frequently in deformity patients, screening MRI, which includes only sagittal and coronal sequences, is a cost effective and time-saving method used to evaluate for spinal cord anomalies, such as a syrinx or Chiari malformation. This study aims to determine the reliability of assessing spinal cord type on screening MRI without apical axial images. Methods: This was a randomized, blinded survey assessment of 4 spinal deformity fellows and 6 attending spinal deformity surgeons. 88 pediatric and 177 adult deformity patients with full sequence spine MRI were identified. From these, 36 patients were randomly selected using a random number generator, and their cord shape type was determined from axial MRI. A survey, featuring scrollable videos of only sagittal and coronal MRI sequences for each patient, was created and completed by the spine surgery attendings and fellows. Our primary objective was quantitatively determining the inter-observer agreement on spinal cord shape type, calculated using Fleiss kappa coefficients. Results: The overall agreement for cord shape type was 67.90% with a moderate Fleiss kappa value of 0.52. Using both sequences, TI cord inter-observer agreement was 59.40% (n = 12, k = 0.39), TII 68.06% (n = 13, k = 0.52), and TIII 78.79% (n = 11, k = 0.68). Coronal MRI evaluation only for patients with coronal deformity showed an inter-observer agreement of 67.74% (k = 0.52). For coronal deformity TI cords, the agreement was 73.31% (k = 0.60), for TII 61.67% (k = 0.42), and for TIII 81.11% (k = 0.72). Sagittal deformity cord shape type determined based on sagittal MRI had an inter-observer agreement of 71.11% (k = 0.57). For specifically sagittal TI cords, the agreement was 50% (k = 0.25), for TII 55.56% (k = 0.33), and for TIII 78.57% (k = 0.68). Additionally, patients with a deformity greater than 60° had a significantly increased risk of TII or TIII cord (53.6° vs 64.6°, p 60 1.37, OR 1.66). Conclusions: The screening MRI sequence showed fair to moderate reliability in determining cord type for TI and TII patients (k = 0.39-0.60), but for TIII patients it was substantially reliable (k = 0.68-0.72). Although axial MRI remains the gold standard for accurately determining spinal cord shape, in patients with a major cobb deformity less than 60°, screening MRI alone is likely sufficient to rule out type 3 cord. Chikara Hayakawa 1 , Ichiro Okano 1 , Yusuke Dodo 1 , Koki Tsuchiya 1 , Yoshifmi Kudo 1 1 Showa University School of Medicine, Tokyo, Japan Introduction: Although surgeons sometimes state whether certain patients “seemingly” have osteoporosis or not, only based on radiographs or computed tomography (CT) images, there is no report assessing diagnostic abilities based on human intuition. This study examined the accuracy of the intuitive diagnosis of low bone mineral density (BMD) by orthopedic surgeons using lumbar spine radiographs and sagittal CT images. Methods: This study was approved by the institutional review board. We recruited board-certified orthopedic surgeons and non-orthopedic specialists, including specialist physicians other than orthopedics or radiologists, medical students, non-specialized interns, and orthopedic residents from our university and affiliated hospitals. Dual-energy X-ray absorptiometry (DXA) was used to diagnose osteoporosis. As the diagnostic criterion for osteoporosis and osteopenia, a T-score cut-off value of -2.5 and -1.0 was used, according to the guidelines of the Japanese Osteoporosis Society. The participants were asked to respond to a binary questionnaire on whether each image corresponded to that of a patient with osteoporosis, using 45 lateral lumbar spine radiographs and CT images. Data on the years of clinical experience, frequency of encountering osteoporosis, and frequency of lumbar spine imaging evaluation were collected. Results: Data from 92 (42 orthopedic and 50 non-orthopedic) evaluators were included in the final analysis. The overall percentages (±standard deviation) of correct answers at the T-score cut-off values of -2.5 and -1.0 were 53.4 ± 8.6% and 50.1 ± 14.4% for radiographs, respectively, 52.9 ± 11.0% and 53.9 ± 14.4% for CT images, respectively. When the T-score cut-off value was changed from -2.5 to -1.0, the diagnostic accuracy rates increased among board-certified orthopedic specialists but decreased among non-specialists for both radiographs (T-score cut-off value, -2.5; 55.2 ± 8.0% vs. 51.9 ± 8.8%; p = 0.098, T-score cut-off value, -1.0; 57.4 ± 11.3 vs. 44.0 ± 9.9%; p < 0.001) and CT images (T-score cut-off value, -2.5; 59.2 ± 9.0% vs. 47.7 ± 9.7%; p < 0.001, T-score cut-off value, -1.0; 63.7 ± 11.9% vs. 45.7 ± 11.0%; p < 0.001). A positive correlation was observed between diagnostic accuracy and years of clinical experience. However, no correlation was observed when the examiners were limited to board-certified orthopedic specialists. A moderate correlation was observed between the diagnostic accuracy of lumbar spine CT and the frequency of image evaluation (r = 0.408, p < 0.001). Otherwise, no correlation was observed between accuracy, frequency of lumbar spine radiographic evaluation, or frequency of encountering patients with osteoporosis. Discussion and Conclusion: The overall accuracy of the intuitive diagnosis of osteoporosis was low for all participants. The accuracy of board-certified orthopedic specialists was slightly better than that of non-specialists. The changes in accuracy when altering the T-score cut-off values suggest that orthopedic specialists used strict internal criteria for osteoporosis, whereas non-specialists did not. The absence of a correlation between the accuracy rates and clinical experience when the examiners were limited to board-certified orthopedic specialists suggests that intuitive diagnostic ability may be primarily developed slowly during training. Although there are potential measurement errors in the DXA method owing to degenerative changes, osteophytes, and calcifications of the great vessels, our results indicate the inherent limitations of the human diagnostic ability for osteoporosis. Therefore, formal diagnostic modalities should be used to determine whether patients have osteoporosis. Esteban Espinoza 1 , Manuel González 1 , Stefano Smoquina 1 , Gonzalo Monroy 2 1 Hospital San Camilo, Division of Neurosurgery, San Felipe, Chile , 2 Universidad de Valparaíso, San Felipe, Chile Introduction: The clinical utility of Hounsfield unit (HU) measurements in lumbar computed tomography (CT) scans for managing osteoporotic spinal fractures has been increasingly recognized. This method is being evaluated as a viable alternative to dual-energy X-ray absorptiometry (DXA) for assessing bone mineral density (BMD) and diagnosing osteoporosis, particularly in patients with spinal pathology. Material and Methods: A narrative literature review was conducted to evaluate the efficacy of HU measurements in CT for the management of osteoporotic spinal fractures. The review included observational studies and systematic reviews published in English or Spanish. The target population comprised adult patients with diagnosed osteoporotic vertebral fractures. The primary outcome was the clinical utility of HU measurements in guiding decision-making for the management of osteoporotic spinal fractures. Studies that did not include HU measurements in CT scans, along with case reports and letters to the editor, were excluded. A comprehensive search was performed in the PubMed database using MeSH terms related to Hounsfield Units, spinal fractures, osteoporosis, computed tomography, bone mineral density, surgery, and prognosis. The search was limited to articles published from 2010 onwards. Two independent reviewers screened the titles and abstracts of the retrieved articles. The full texts of eligible studies were subsequently reviewed to ensure adherence to inclusion and exclusion criteria. Any disagreements were resolved by consulting a third reviewer. Extracted data were tabulated, and a narrative synthesis was conducted. Results: Correlation between HU and BMD: - HU values from CT scans correlate significantly with BMD and T-scores obtained from DXA, suggesting that HU can be a reliable indicator of bone quality. - HU measurements are particularly useful in patients with degenerative spinal diseases where DXA may overestimate BMD due to calcifications and other artifacts. Threshold values for diagnosing osteoporosis: - Several studies have identified specific HU thresholds for diagnosing osteoporosis. Commonly cited thresholds include 110 HU for L1, 100 HU for L2, 85 HU for L3, and 80 HU for L4. - A meta-analysis suggests a threshold of 135 HU for diagnosing osteoporosis. - Clinical utility in surgical planning: - HU measurements can inform surgical planning by predicting the success of spinal instrumentation and the risk of complications such as screw loosening and cage subsidence. - HU values have been shown to correlate with biomechanical strength, further supporting their use in preoperative assessments. Opportunistic screening: - HU measurements can be obtained from existing CT scans performed for other reasons, providing a method for osteoporosis screening. - This opportunistic screening can help identify undiagnosed osteoporosis, particularly in lumbar degenerative diseases. - Machine learning applications: - Machine learning models using HU values from CT scans can accurately predict osteoporotic status, potentially enhancing diagnostic accuracy and aiding in clinical decision-making. Conclusion: The measurement of HU in lumbar CT scans is a valuable tool for managing osteoporotic spinal fractures. It offers a reliable alternative to DXA, particularly in patients with degenerative spinal conditions, aids in surgical planning, facilitates opportunistic screening, and may enhance diagnostic accuracy with machine learning models. Frank Hassel 1 , Babak Saravi 2 , Alisia Zink 1 , Uelkuemen Sara 1 , Sébastien Couillard-Després 3 , Gernot Michael Lang 2 1 Loretto Hospital, Spine Surgery, Freiburg, Germany , 2 Faculty of Medicine University of Freiburg, Orthopedics and Trauma Surgery, Freiburg, Germany , 3 Paracelsus University Salzburg, Institute of Neuroregeneration, Salzburg, Austria Introduction: Low back pain is a widely prevalent symptom and the foremost cause of disability on a global scale. Although various degenerative imaging findings observed on magnetic resonance imaging (MRI) have been linked to low back pain and disc herniation, none of them can be considered pathognomonic for this condition, given the high prevalence of abnormal findings in asymptomatic individuals. Nevertheless, there is a lack of knowledge regarding whether radiomics features in MRI images combined with clinical features can be useful for prediction modeling of treatment success. The objective of this study was to explore the potential of radiomics feature analysis combined with clinical features and artificial intelligence-based techniques (machine learning/deep learning) in identifying MRI predictors for the prediction of outcomes after lumbar disc herniation surgery. Material and Methods: We included n = 172 patients who underwent discectomy due to disc herniation with preoperative T2-weighted MRI examinations. Extracted clinical features included sex, age, alcohol and nicotine consumption, insurance type, hospital length of stay (LOS), complications, operation time, ASA score, preoperative CRP, surgical technique (microsurgical versus full-endoscopic), and information regarding the experience of the performing surgeon (years of experience with the surgical technique and the number of surgeries performed at the time of surgery). The present study employed a semiautomatic region-growing volumetric segmentation algorithm to segment herniated discs. In addition, 3D-radiomics features, which characterize phenotypic differences based on intensity, shape, and texture, were extracted from the computed magnetic resonance imaging (MRI) images. Selected features identified by feature importance analyses were utilized for both machine learning and deep learning models (n = 17 models). Results: The mean accuracy over all models for training and testing in the combined feature set was 93.31 ± 4.96 and 88.17 ± 2.58. The mean accuracy for training and testing in the clinical feature set was 91.28 ± 4.56 and 87.69 ± 3.62. Conclusion: Our results suggest a minimal but detectable improvement in predictive tasks when radiomics features are included. However, the extent of this advantage should be considered with caution, emphasizing the potential of exploring multimodal data inputs in future predictive modeling. Erika Chiapparelli 1 , Ranqing Lan 2 , Krizia Amoroso 1 , Ali Guven 1 , Gisberto Evangelisti 1 , Paul Koehli 1 , Jan Hambrecht 1 , Bruno Verna 1 , Koki Tsuchiya 1 , Jiaqi Zhu 2 , Jennifer Shue 1 , Andrew Sama 1 , Federico Girardi 1 , Frank Cammisa 1 , Alexander Hughes 1 1 Hospital for Special Surgery, Spine Surgery, Research, NYC, United States , 2 Hospital for Special Surgery, Biostatistics Core, Research, NYC, United States Introduction: Alcohol abuse, characterized by excessive consumption leading to health risks as defined by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), significantly contributes to tissue degeneration. Chronic alcohol intake elevates acetaldehyde levels, a damaging metabolite, which accelerates collagen type I degradation across various tissues, including skin and bone. Recent studies have highlighted the link between skin dermal ultrasound (US) echogenicity and bone quality. Despite this, there remains a limited number of studies on US as a biomarker for tissue degeneration. This study hypothesizes that alcohol abuse correlates with increased dermal US echogenicity, poor tissue quality, and reduced skin thickness (ST), suggesting the utility of skin US for preoperative assessment of bone quality in lumbar fusion patients. We aim to explore the relationship between skin US parameters and alcohol abuse in patients with lumbar spine degenerative disease undergoing open lumbar fusion surgery. Material and Methods: We identified patients with a history of alcohol abuse (more than 14 drinks per week for males, more than 8 for females) undergoing open lumbar fusion surgery. Patients lacking preoperative US were excluded. US measurements were taken at two standardized lumbar locations, evaluating the average dermal (AD) layer, upper 1/3 of the dermal (UD) layer, and lower 1/3 of the dermal (LD) layer. ST was assessed at three dermal sites, with averages used for analysis. Echogenicity and ST were calculated using our institution’s imaging platform. The Wilcoxon rank sum and Fisher’s Exact tests analyzed continuous and categorical variables, respectively. Linear regression, adjusted for age, sex, and BMI, examined the relationship between alcohol abuse and US parameters, with statistical significance set at p < 0.05. Results: Of 466 patients undergoing posterior lumbar fusion, 459 (50.5% male, median age 63.67 years [55.35, 71.83], BMI 28.74 kg/m2 [25.40, 33.00]) were included after excluding 7 with missing skin US measurements. Female patients had significantly higher US echogenicity values in the dermal layer (median AD: 121 [110.75, 133.25], UD: 119 [107.35, 128.25], LD: 124.75 [110.75, 141.75]) compared to males (median AD: 111.75 [98.92, 124.50], UD: 112.25 [102.06, 120.13], LD: 115.5 [98.14, 131.75]), p < 0.0001. Conversely, ST was significantly higher in males (2.97 [2.59, 3.38]) than in females (2.65 [2.21, 3.01]), p < 0.0001. Alcohol abuse history was associated with increased LD echogenicity (regression coefficient 14.86 [0.85-28.87], p < 0.038) and decreased ST (0.35 [-0.67- -0.03], p = 0.034). Conclusion: We found a significant association between high alcohol consumption and dermal layer degradation as measured by US. This supports existing evidence linking excessive alcohol intake to tissue impairment and highlights the potential of skin US as a preoperative biomarker for bone quality in fusion surgery patients. Our study contributes to the growing body of literature on US utility in this context and highlights the need for further research to fully understand the clinical implications and develop therapeutic strategies. Stone Sima 1 , Xiaolong Chen 2 , Kyle Sheldrick 1 , Allen Lu 1 , Victor Martin-Gorgojo 3 , Brian Hsu 3 , Ashish Diwan 1 4 5 1 Spine Labs, St George and Sutherland Clinical School, University of New South Wales, Sydney, Australia , 2 Department of Orthopaedics, Xuanwu Hospital, Capital Medical University, Beijing, China , 3 NSW Spine Specialists, Sydney, Australia , 4 Spine Service, Department of Orthopaedics, St George Hospital, Sydney, Australia , 5 Chair of Spine Surgery, Discipline of Orthopaedic Surgery, School of Medicine, University of Adelaide, Adelaide, Australia Introduction: Isthmic spondylolisthesis (IS) is defined as the anterior translation of one lumbar vertebra relative to the next caudal segment as a result of a unilateral or bilateral fracture of the pars interarticularis. These fractures are interchangeably known as “pars defects” or “spondylolysis”. Many risk factors have been proposed to explain the progression of a spondylolytic defect to IS, however, none are validated . This systematic review provides an overview of various radiological and imaging parameters that can help predict the risk of progression of a spondylolytic defect into IS. Materials and Methods: Medline, Embase and Cochrane online database were searched. The various correlations between imaging features with observed spondylolisthesis prevalence or severity or spondylolysis rates of spondylolisthesis were evaluated to provide a list of imaging risk factors to predict IS. Significance of the correlations in the original article was recorded to enable comparison of the collected evidence of separate image features. Results: All searches combined generated a total of 431 results of which 26 articles were included into this study. Of the 22 potential risk factors identified, 5 were found to be statistically insignificant, 8 were found to be significant and 9 had mixed results. The following features were found to be significant risk factors in at least on study: Disc degeneration, Transverse process width, Pelvic Incidence, Pelvic tilt, Sacral Slope, Lumbar lordosis, Lumbar Index, Thoracic Kyphosis, Facet Joint angle above the level of defect, Facet Joint Degeneration, Facet Tropism, Multifidus size, Lateral Erector Spinae Size, Mesenteric Fat Thickness, Subcutaneous Fat Thickness and Soft tissue calcification. Conclusion: Our research suggests that only disc degeneration had a moderately strong evidence with consistent significant associations with development of IS in patients with spondylolysis. Transverse process width, Pelvic Incidence, Pelvic tilt, Sacral Slope, Lumbar lordosis, Lumbar Index, Thoracic Kyphosis, Facet Joint angle above the level of defect, Facet Joint Degeneration, Facet Tropism, Multifidus size, Lateral Erector Spinae Size, Mesenteric Fat Thickness, Subcutaneous Fat Thickness and Soft tissue calcification had some evidence. All other radiological factors had weak evidence. The results of this study can be used to improve early clinical decision making for patients with spondylolysis. Erika Chiapparelli 1 , Krizia Amoroso 1 , Ali Guven 1 , Ranqing Lan 2 , Gisberto Evangelisti 1 , Paul Koehli 1 , Jan Hambrecht 1 , Bruno Verna 1 , Koki Tsuchiya 1 , Jiaqi Zhu 1 , Jennifer Shue 1 , Andrew Sama 1 , Federico Girardi 1 , Frank Cammisa 1 , Alexander Hughes 1 1 Hospital for Special Surgery, Spine Surgery, Research, NYC, United States , 2 Hospital for Special Surgery, Biostatistics Core, Research, NYC, United States Introduction: Collagen quality plays a crucial role in bone strength and can impact surgical outcomes. Recent studies suggest that skin ultrasound (US) parameters might serve as biomarkers for bone collagen quality, given the shared presence of collagen type I in both skin and bone. Anti-osteoporotic medications such as denosumab, teriparatide, and bisphosphonates are often prescribed to enhance bone mineral density (BMD) in patients with deteriorated bone quality. This study explores the relationship between skin US and anti-osteoporotic medication in patients with severe osteoporosis undergoing lumbar fusion surgery. We hypothesize that patients on these medications will show higher US echogenicity in the dermal layer, indicative of poor tissue quality, potentially reflecting changes in tissue composition due to their osteoporotic condition and treatment. Material and Methods: Patients undergoing lumbar fusion surgery were enrolled, excluding those without preoperative US measurements. We identified patients with a history of osteoporosis treated with denosumab, teriparatide, or bisphosphonates. US measurements were taken at two standardized lumbar locations, assessing skin echogenicity in the average dermal (AD), upper 1/3 of the dermal (UD), and lower 1/3 of the dermal (LD) layers. Skin thickness (ST) was measured at three dermal sites, and averages were used for analysis. Measurements were calculated using our institution’s imaging platform (PACS). The Wilcoxon rank sum and Fisher’s Exact tests analyzed continuous and categorical variables, respectively. Linear regression analysis, adjusted for age, sex, BMI, and BMD, examined the relationships between anti-osteoporotic medications and US parameters, with statistical significance set at p < 0.05. Results: Of 466 patients undergoing posterior lumbar fusion, 459 (50.5% male, median age 63.7 years [55.3, 71.9], BMI 28.7 [25.4, 33], BMD 112.75 [88, 137]) were included after excluding 7 with missing skin US measurements. A linear regression analysis for each medication revealed that 44 patients on denosumab, bisphosphonates, or teriparatide had significantly higher US echogenicity in the LD: denosumab RC 12.4 [1.4-23.5] (p = 0.03), bisphosphonates RC 13.9 [0.7-27.3] (p = 0.04), and teriparatide RC 14.6 [3.2-25.9] (p = 0.01). Denosumab was associated with a significant decrease in ST (RC -0.3 [-0.6- -0.04]). Combining data from all medication groups, there was a significant increase in US echogenicity in the AD (RC 10.9 [4.7-17.1]) and LD (RC 16.4 [8.8-24.01], p < 0.001), and a decrease in ST (RC -0.34 [-0.5- -0.2], p = 0.001). Conclusion: Our study shows significant associations between skin US parameters and anti-osteoporotic medication in patients undergoing lumbar fusion surgery. Patients on these medications exhibited higher US echogenicity, particularly in the LD, and lower ST. These changes may reflect the severity of osteoporosis rather than the medications themselves. These findings highlight the need for comprehensive assessment and management strategies for osteoporosis patients undergoing surgery. Further research is needed to understand the mechanisms behind these associations and to optimize clinical outcomes. Ali Guven 1 , Kyle Finos 1 , Isaac Nathoo 1 , Marco Burkhard 1 , Erika Chiapparelli 1 , Paul Koehli 1 , Jan Hambrecht 1 , Gisberto Evangelisti 1 , Bruno Verna 1 , Koki Tsuchiya 1 , Jennifer Shue 1 , Andrew Sama 1 , Federico Girardi 1 , Frank Cammisa 1 , Alexander Hughes 1 1 Hospital for Special Surgery, New York, United States Introduction: Paraspinal muscle atrophy is linked to degenerative spine conditions, chronic back pain, and poor postoperative outcomes. Commonly assessed parameters, such as fatty infiltration (FI) and functional cross-sectional area (fCSA), overlook lean muscle quality. Increased T2 MR imaging intensity is a proposed marker for muscle aging, associated with reduced function. We introduce a novel paraspinal muscle quality (PMQ) score, normalizing T2 intensity of lean muscle to cerebrospinal fluid (CSF), and aim to examine its relationship with key demographics, conventional atrophy parameters and functional status. Methods: Patients who underwent lumbar spinal surgery for degenerative lumbar disease from December 2014 to July 2023 were analyzed. Data collected included age, sex, BMI, smoking status, hypertension, diabetes, ASA score, vertebral bone mineral density (BMD), and functional status as assessed by the Oswestry Disability Index (ODI) and its subsections. Erector spinae and multifidus muscles were segmented at the L4 upper endplate on axial T2-weighted MRI. Fat and muscle areas were determined using automated signal intensity thresholding, with fCSA defined as lean muscle area normalized to height squared. FI percentage was calculated as fat area divided by total muscle area. A region of interest (ROI) was set at the same axial level in the cerebrospinal fluid (CSF) or the closest level if stenosis was present. The PMQ score was the ratio of lean muscle intensity to CSF intensity, ranging from 0 to 1. Right and left measurements were averaged. Interrater agreement for PMQ in 46 randomly selected patients was assessed using ICC. Spearman’s correlation was used to analyze parameter relationships. Proportional odds models with ordinary outcomes were used to assess the relationship between multifidus PMQ and the ODI-subsection pain intensity, adjusting for age, sex, BMI, and FI. Results: A total of 481 patients (53.4% female) with a median age of 66 years (IQR: 58 - 72) were included. For both muscles, PMQ had a highly significant positive correlation (p < 0.01) with age, female sex, BMI, ASA score, and hypertension. A highly significant negative correlation was observed with vertebral BMD. Both erector spinae and multifidus PMQ had a significant positive correlation with corresponding muscle FI with a rho of 0.50 and 0.52, respectively (p < 0.001), and a significant negative correlation with muscle fCSA with a rho of -0.10 (p = 0.037) and -0.12 (p = 0.006), respectively. Multifidus PMQ significantly predicted pain intensity with an odds ratio of 4.39 (95% CI: 1.13 – 17.08, p = 0.033). The interrater reliability for PMQ was high for both muscle groups, with an ICC estimate of 0.867 (95% CI: 0.720 to 0.932) for erector spinae and 0.874 (95% CI: 0.767 to 0.931) for multifidus. Conclusion: The novel PMQ score correlates with age, female sex, BMI, comorbidities, and predicts low back pain. As a potential indicator of muscle aging, this parameter can be integrated into paraspinal muscle assessment and implemented in future research in addition to conventional parameters. Erika Chiapparelli 1 , Ali Guven 1 , Quinton Wright 1 , Paul Koehli 1 , Ranqing Lan 2 , Krizia Amoroso 1 , Gisberto Evangelisti 1 , Jan Hambrecht 1 , Bruno Verna 1 , Koki Tsuchiya 1 , Jiaqi Zhu 1 , Jennifer Shue 1 , Eve Donnelly 1 , Andrew Sama 1 , Federico Girardi 1 , Frank Cammisa 1 , Alexander Hughes 1 1 Hospital for Special Surgery, Spine Surgery, Research, New York, United States , 2 Hospital for Special Surgery, Biostatistics Core, Research, New York, United States Introduction: Collagen type I is vital for the strength and functionality of bone and other supportive tissues, including tendons, ligaments, and skin. In bone, collagen undergoes modifications such as non-enzymatic cross-linking, forming advanced glycation endproducts (AGEs) that are linked to compromised bone quality. Although bone AGEs can be quantified via biopsy, this is impractical for preoperative assessments, especially in spine patients. Dermal ultrasound (US) offers a non-invasive alternative to assess dermal properties microscopically. While previous studies have associated skin US parameters with AGEs measured by confocal fluorescence microscopy, the relationship between dermal US and AGEs assessed by Second Harmonic Generation (SHG), which provides additional details about bone collagen fibers, remains underexplored. This study aims to determine if dermal US measurements correlate with AGEs in lumbar fusion patients, potentially serving as a non-invasive biomarker. Material and Methods: We conducted a single-center cross-sectional analysis using a prospectively maintained database. Patients undergoing open lumbar fusion surgery from 2014 to 2021 who consented to preoperative US dermal measurements and intraoperative iliac crest bone biopsy were included. Exclusion criteria included the absence of both preoperative US and bone biopsy. US measurements were taken at two standardized lumbar locations. We measured skin echogenicity in the average dermal (AD), upper 1/3 of the dermal (UD), and lower 1/3 of the dermal (LD) layers. Echogenicity was calculated using our institution’s imaging platform. Bone biopsies were imaged using multiphoton microscopy to assess collagen crosslink density and alignment. SHG imaging was employed to capture collagen structures, and metrics like fibril ellipticity and homogeneity were calculated using custom MATLAB scripts. Statistical analysis included the Wilcoxon rank sum test, Chi-Squared, Fisher’s Exact tests and linear regression adjusted for age, sex, BMI, and diabetes mellitus p < 0.05. Results: We enrolled 204 patients undergoing posterior lumbar fusion, excluding 31 due to missing bone biopsies or skin US measurements. The final cohort included 173 patients (50.9% female, median age 62.2 years [54.2, 70.1], BMI 29.41 kg/m2 [26.6, 35.1]). Female patients had significantly higher US echogenicity in the dermal layer (median AD: 119.3 [104.5, 130.3], UD: 122.5 [112.4, 132.4], LD: 118 [101.2, 133]) compared to males (median AD: 108.3 [94.1, 120.7], UD: 116.5 [109.4, 123.9], LD: 104.7 [88.6, 122.5]), p < 0.001. No significant differences were found in SHG parameters between sexes. Linear regression analysis indicated that LD echogenicity significantly predicted collagen crosslink density in both cortical (Estimate: 0.054, 95% CI: 0.0025 - 0.1051, p = 0.040) and trabecular bone (Estimate: 0.076, 95% CI: 0.0162 - 0.1359, p = 0.013). Conclusion: Dermal US parameters, particularly LD echogenicity, are predictive of AGE accumulation in bone. These findings support the notion that changes in skin collagen may reflect underlying bone collagen alterations, reinforcing the potential of non-invasive dermal ultrasound as a tool for evaluating bone quality. This approach could be especially valuable for assessing patients at risk of poor surgical outcomes due to compromised bone health, improving clinical decision-making in lumbar fusion surgery. Further research is warranted to validate these findings and explore the clinical implications. Luke Pearson 1 , Seung Lee 2 , Jared Weeks 1 , Emilio Supsupin 1 , Daryoush Tavanaiepour 1 , Kourosh Tavanaiepour 1 , Dunbar Alcindor 1 , Aboubakr Amer 1 , Vashisht Sekar 1 1 University of Florida Jacksonville, Jacksonville, United States , 2 Mayo Clinic Jacksonville, Jacksonville, United States Introduction: Subaxial cervical pedicle screws (C3-C7) are increasingly utilized in complex cervical spine reconstructions, offering greater fixation strength compared to traditional techniques. However, anatomical variability and potential for screw malpositioning raise concerns regarding the safety and efficacy of this technique. First described by Abumi et al. in 1994, cervical pedicle screw fixation provided high stability and strength in the treatment of traumatic cervical spine injuries without any neurovascular complications in an era prior to neuronavigation. Cervical pedicle screws are considered riskier than lateral mass screws and generally reserved for situations in which lateral mass instrumentation is not possible. Measurement techniques have evolved, with advancements in imaging modalities playing a pivotal role in preoperative planning. CT scans are increasingly utilized to obtain precise measurement of pedicle dimensions, allowing for tailored screw selection. This study aimed to quantify subaxial cervical pedicle diameters in a large cohort using computed tomography (CT) scans to provide valuable anatomical data for surgical planning and screw selection. Material and Methods: This study analyzed 50 consecutive CT scans of the cervical spine from patients without previous cervical surgery. All scans were acquired using a standardized protocol with 1 mm slice thickness. The diameters of the subaxial cervical spine pedicles were measured (250 vertebrae or 500 pedicles). The measurements were performed using the measurement tools of the CT imaging software. The pedicle diameters were measured based off the most outer cortex of the pedicle, taken perpendicular to the axis of the pedicle, and measured in millimeters up to 0.1 mm. Results: The mean transverse diameters of the cervical pedicles of C3, C4, C5, C6, and C7 in males were 5.1, 5.3, 5.6, 5.9, and 6.6, respectively. The mean transverse diameters of the cervical pedicles of C3, C4, C5, C6, and C7 in females were 4.5, 4.5, 4.9, 5.0, and 6.0, respectively. Using a transverse diameter cutoff of 4 millimeters necessary to accommodate a 3.5-millimeter screw, between 0% and 13.4% of pedicles in our male population could not have pedicle screw fixation and between 0% and 21.1% of pedicles in our female population could not have pedicle screw fixation. Conclusion: This study provides a comprehensive quantitative analysis of subaxial cervical pedicle diameters in a large cohort, highlighting the significant anatomical variations present within this region. The results emphasize the importance of pre-operative planning and meticulous screw selection to ensure accurate placement and minimize the risk of complications. These data can inform surgical decision-making and aid in choosing appropriate screw sizes and trajectories, ultimately contributing to safer and more effective cervical spine surgeries utilizing subaxial cervical pedicle screws. Further research exploring the impact of other factors, such as age, ethnicity, bone density, and degenerative changes, on pedicle dimensions, is warranted to enhance our understanding of cervical spine anatomy and improve patient outcomes. Arman Zaden 1 , Erika Chiapparelli 1 , Krizia Amoroso 1 , Paul Koehli 1 , Jiaqi Zhu 1 , Ali Guven 1 , Gisberto Evangelisti 1 , Jan Hambrecht 1 , Koki Tsuchiya 1 , Jennifer Shue 1 , Andrew Sama 1 , Federico Girardi 1 , Frank Cammisa 1 , Alexander Hughes 1 1 Hospital for Special Surgery, Spine Surgery, Research, NYC, United States Introduction: Sarcopenia, characterized by progressive loss of skeletal muscle mass and function, significantly impacts patients with lower back pain, increasing disability, fall risk, fractures, and surgical needs, thereby affecting quality of life. While glucagon-like peptide-1 agonists (GLP-1a) are well-known for managing diabetes and obesity, their effects on muscle quality, size, and function remain poorly understood. This study investigates how GLP-1a use affects muscle functional cross-sectional area (fCSA) and fatty infiltration (FI), focusing on paraspinal muscles over time. Material and Methods: We reviewed non-surgical patients at a single orthopedic hospital diagnosed with lower back pain and diabetes who had been on GLP-1a since 2014. Exclusion criteria included previous lumbar decompression or fusion, inadequate MRI imaging, inconsistent GLP-1a use, or significant comorbidities. Muscle measurements were taken at two time points for each patient: baseline before GLP-1a use and a secondary measurement between 6 to 24 months after starting GLP-1a. Using ITK-SNAP version 3.8, we segmented the bilateral psoas, erector spinae (ES), and multifidus (MF) muscles from preoperative T2-weighted axial MR images at the superior endplate of L4. We calculated total muscle, fCSA, fat content, and muscle FI areas with a custom Matlab™ program. Measurements were normalized to baseline values to account for interpatient variability. Statistical analysis used the Kruskal-Wallis test and Pearson’s correlation for continuous variables, and chi-square and Fisher’s Exact tests for categorical variables. Statistical significance was set at p < 0.05. Results: We reviewed 216 non-surgical patients on GLP-1a with at least two images taken 3 months apart. The final analysis included 41 patients (61% male, median age 67 years [IQR 60-72]). Baseline imaging was within a year of starting GLP-1a. At 6 months, 7 (17%) patients had imaging, 23 (56%) had imaging at 12 months, and 21 (51%) had imaging at 24 months. At 12 months, there was a significant increase in FI of the ES (median 7% [IQR 1.01, 1.13], p < 0.001) and a significant decrease in the fCSA of the MF (median 15% [IQR 0.78, 0.97], p < 0.001). At 24 months, there was a significant increase in FI for both the ES (median 14% [IQR 1.06, 1.26], p < 0.001) and MF (median 18% [IQR 1.04, 1.26], p < 0.001), along with a decrease in fCSA for both the ES (median 12% [IQR 0.73, 0.96], p < 0.001) and MF (median 14% [IQR 0.73, 0.96], p < 0.001). No significant changes were observed at 6 months. Conclusion: This study finds that diabetic non-surgical back pain patients using GLP-1a experience decreased fCSA and increased FI in posterior paraspinal muscles at 12 and 24 months. These results suggest that GLP-1a use may contribute to the progression of sarcopenia. Further research is needed to fully understand the impact of GLP-1a on muscle quality, particularly for patients at risk of sarcopenia. Future analyses will compare these findings with matched diabetic controls. Luke Jouppi 1,2 , Christopher Seidel 3 , Clifford Pierre 1,2 , Gerrit Lewik 1,2,4 , Luke DiPasquale 5 , Chelsea Bush 3 , Amit Patel 6 1 Seattle Science Foundation, Seattle, United States , 2 Swedish Neuroscience Institute, Seattle, United States , 3 WellSpan Health, York, United States , 4 Ruhr University Bochum, BG University Hospital Bergmannsheil, Department of General and Trauma Surgery, Bochum, Germany , 5 Kettering Health, Dayton, United States , 6 OSS Health, York, United States Introduction: Cervical stenosis is commonly treated with anterior cervical discectomy and fusion (ACDF) performed through a Smith-Robinson approach. Recently, facet fusion achieved with implantable devices from a posterior approach has been described as an alternative. To our knowledge, no anatomic studies have been performed comparing the combined surface area of the facet joints to the surface area of the intervertebral space. This study aimed to evaluate the cervical facet joints versus the interbody spaces and provide a better understanding of the potential surface area for fusion surgery. Methods: We performed a cross-sectional retrospective review using cervical spine CT scans conducted from 2014-2017. Using our institution’s imaging software, we measured the area within the intervertebral space and the facet joints bilaterally. Surface areas for each intervertebral space were compared using a paired t-test to the cumulative surface area of the facet joints calculated at each level. Results: Two-hundred twelve patients (120 male, 92 female) were eligible for the analysis based on our inclusion and exclusion criteria. The mean age was 33 years (range 18-55). The mean BMI was 29 (range 19-58). In each of the comparisons, the combined intra-facet joint surface area (IFSA) was significantly greater than the intervertebral surface area (IVSA) of the corresponding interbody space. Conclusion: Our study found that the surface area between the IFSA is two to three times greater than the IVSA. This study may help establish an anatomic basis for comparable fusion results between the traditional intervertebral space method and an intra-facet joint fusion. Thiago Coutinho 1 , Carlos Tucci 1 , Rafael Sugino 1 , Alipio Omand 2 , Marco Ratti 2 , Rafael Marcon 3 , Alexandre Fogaça 3 1 Instituto VITA, São Paulo, Brazil, 2 Radiologia Fleury, São Paulo , 3 IOT - Instituto de Ortopedia e Traumatologia HCFMUSP, São Paulo, Brazil Introduction: With the rise of single-position surgery, two main frameworks for LLIF in a single position have been developed: one with the patient in the prone position and the other with the patient in the traditional lateral position, each with its own set of advantages and limitations. Thus, understanding the movement dynamics of important structures, such as the psoas muscle and lumbar plexus, that occur in different positions is crucial to evaluate the safety of the procedures. Material and Methods: Cross-sectional imaging study. Ten volunteers underwent lumbar magnetic resonance imaging in four different positions: dorsal, prone, right lateral decubitus, and left lateral decubitus. Support pads were used to emulate the true surgical position in the prone and lateral decubitus positions. The following measures were used: size of the vertebral body, distance from the tip of the psoas to the anterior border of the vertebral body (negative values indicating posterior to the anterior margin of the vertebral body), and distance from the lumbar plexus to the posterior wall of the vertebral body (negative values indicating posterior to the posterior border). All relative values (in relation to vertebral body size) were derived from the mean vertebral body size (i.e., VBZ dorsal + VBZ prone + VBZ right + VBZ left ). In order to evaluate the psoas and plexus, only the “free-psoas” of the lateral decubitus was considered (i.e: left psoas from the right lateral decubitus). The mean variance between the groups was compared using the permutation Welch t-test, in the case of non-Gaussian distribution, or the traditional Welch t-test, in the case of normal distributions. p was set at p < 0.05. Results: When comparing the distance of the anterior margin of the left psoas muscle between the right decubitus and ventral decubitus, there were significant differences in the L3L4 [p = 0.049; effect size = -0.28; SE = 0.09] and L4L5 levels (p = 0.03; effect size = -0.29, SE = 0.09]. However, when comparing the anterior margin dislocation of the right psoas muscle between the left decubitus and ventral decubitus, there were significant differences in the L4L5 level [p = 0.02, effect size = -0.12; SE = 0.04), but there was no difference in the L3L4 disc level [p = 0.16]. When comparing the plexus distance from the posterior margin of the vertebral body in relation to the vertebral body size, there were no significant differences between the L3L4 level [p = 0.58] or the L4L5 level [p = 0.18] when comparing the left plexus between the right decubitus and ventral decubitus. Similarly, no significant difference was found between the right plexus position at the L3L4 [p = 0.4] or L4L5 [p = 0.06] level. Conclusion: When positioning the patient in a lateral decubitus there is an inherently shift of the “free-psoas” towards an anterior position when compared to the ventral positioning. However, a similar shift was not observed when analyzing the lumbar plexus between the lateral and ventral decubitus positions. Liam Rose 1 , James Geddes 1 , Tesfaladet Kurban 1 , Libby Gooda 1 , Marijn van Stralen 2 , Peter Seevinck 2 , Peter Terjanian 3 , Zachary Dossett 3 , Mary Smitheman 4 , Helen Adams 5 , Timothy Bishop 1 , Darren Lui 1 , Jason Bernard 1 1 St George's University Hospital, London, United Kingdom , 2 MRI Guidance, Utrecht, Netherlands , 3 Mighty Oak Medical, Colorado, United States , 4 Edge Medical, Manchester, United Kingdom , 5 Ovidius Medical, Worcestershire, United Kingdom Background: CT scans can be used to produce custom made spine models to guide accurate pedicle screw insertion. The main drawback, similar to intraoperative navigation, is radiation dose. A novel option is to use a Synthetic CT generated from an MRI scan. We compared Synthetic CT to traditional CT scans to establish if they could produce similar spine models on which to base jigs and plan screw trajectory. Methods: We obtained MRI and CTs on 2 consecutive scoliosis patients. Pre-op planning CT with 0.625 mm axial cuts were taken. Simultaneous MRI scans were obtained and automatically converted to synthetic CTs using BoneMRI software. The Original CT and synthetic CT were segmented for Firefly 3D model creation at each vertebral level. Both models were virtually overlaid and compared for similarity with volumetric analysis. This produced a Dice coefficient to statistically compare the similarity at each vertebral level for both modalities. Results: Analysis was possible at 30 vertebral levels, due to exclusions because of cut-offs. The mean Dice coefficient was 0.94 (Thoracic mean 0.94, Lumbar mean 0.95). Discussion: Both scan types were successfully converted into virtual models capable of planning screw trajectories, 3D printed models & jigs. Segmentations from the traditional and synthetic CT demonstrated high dice coefficients when compared to levels reported in literature (0.8875). The Synthetic CT produced a highly comparable model to Standard CT, and would make it possible to produce accurate custom jigs using synthetic CT alone. This could obviate the need for additional radiation and cost of planning CTs. Thiago Coutinho 1 , Carlos Tucci 1 , Rafael Sugino 1 , Alipio Omand 2 , Marco Ratti 2 , Rafael Marcon 3 , Alexandre Fogaça 3 1 Instituto VITA, São Paulo, Brazil , 2 Radiologia Fleury, São Paulo, Brazil, 3 IOT - Instituto de Ortopedia e Traumatologia HCFMUSP, São Paulo, Brazil Introduction: Anterior lumbar interbody fusion (ALIF) is one of the oldest and most well established interbody fusion techniques. This technique is feasible for the treatment of a wide range of pathologies, including simple disc degeneration and complex high-grade spondylolisthesis. With the advancement of concepts and technology in spinal surgery, the ALIF technique can be performed in a lateral frame, allowing true single-position surgery. Although this technique has proven to be safe, some concerns have been raised regarding the surgical window in lateral ALIF. Therefore, the aim of the present study was to investigate the safety corridor of anterior lumbar interbody fusion in the lateral decubitus position. Material and Methods: Cross-sectional imaging study. Ten volunteers underwent lumbar magnetic resonance imaging in three different positions: dorsal, right lateral decubitus, and left lateral decubitus. The following measurements were taken: angle between the center of the vertebral body and inner margin of the iliac vein, distance between the two iliac veins, total peritoneal area, and peritoneal area in the relevant hemisphere of access. To assess the impact of patient decubitus position on the investigated metrics, the generalized linear mixed model technique was utilized, and the estimated marginal mean (contrast) technique was used to investigate the differences between each position. P was set at p < 0.05. Results: There were no significant differences between the groups in terms of angulation between the center of the vertebral body and the iliac vein. Similarly, there were no significant differences in the distance between the iliac veins between groups. When analyzing the peritoneal content, there was a significant difference between the peritoneal content in the dorsal decubitus and the content in the right lateral decubitus (effect size: -5811 mm 2 ; p = 0.01), and between the dorsal decubitus and the left lateral decubitus (effect size: -5503 mm 2 ; p = 0.01). Interestingly, there was only a difference in the “surgical hemisphere” peritoneal content when comparing the dorsal decubitus and left lateral decubitus positions (-1290 mm 2 , p = 0.02). Finally, there was no difference between the skin incisions in the different decubitus positions. Conclusion: The present study suggests that there is no significant difference between in the surgical corridor between what is seen in the dorsal MRI and in the lateral MRIs, except for an increase in the peritoneal content, both total and surgical side. Furthermore, the study demonstrated that there was no significant difference in the surgical corridor between patients in the left or right decubitus position. Thiago Coutinho 1 , Carlos Tucci 1 , Rafael Sugino 1 , Alipio Omand 2 , Marco Ratti 2 , Rafael Marcon 3 , Alexandre Fogaça 3 1 Instituto VITA, São Paulo , 2 Radiologia Fleury, São Paulo, Brazil, 3 IOT - Instituto de Ortopedia e Traumatologia HCFMUSP, São Paulo, Brazil Introduction: The OLIF is a safe and effective technique to treat both degenerative and deformity cases. The key aspect of this technique is that it allows for the placement of a relatively large cage in a pseudo-corridor that is created between the major vessels and the anterior margin of the psoas muscle, thus reducing the risks of vascular and neurological injuries, feared in ALIFs or LLIFs. However, given the lateral position of the patient to perform the OLIF technique, it is not clear if is possible to trust the OLIF corridor seen in the dorsal MRI when evaluating the feasibility of the technique. Therefore, the aim of the present study is to evaluate the OLIF corridor in both dorsal decubitus and in left lateral decubitus. Material and Methods: Cross-sectional imaging study. Twenty-eight volunteers underwent lumbar magnetic resonance imaging in two different positions: Dorsal and right lateral decubitus. The following measure was taken size of the OLIF corridor [distance between the inner most part of the psoas muscle and the inner most portion of the aorta/iliac arteries]. The mean variance between the groups was compared using the permutation Welch t-test, in the case of non-Gaussian distribution, or the traditional Welch t-test, in the case of normal distributions. P was set at p < 0.05. Results: The mean values of the corridor size decreased in more caudal levels significantly in more caudal levels compared to cranial levels (p = 0.04). When comparing the corridor size between the decubitus, the only level that presented a statical significant difference was the L1L2 (p = 0.02; effect size = -3.41, SE = 1.5), with the patients in a lateral right decubitus presenting a significantly greater corridor space. For the other level the effects size and p values were as follows, L2L3 [effect size: 1.80; p = 0.2], L3L4 [0.84; p = 0.3] and L4L5 [2.23; p = 0.19]. When investigating the corridor size of the patients and the permitted antero-posterior size of the cages, the majority of the corridors in lateral decubitus allowed an 8mm cage (82%), for the 10 mm cage, 74% of the corridors were feasible, for the 14mm cage, 48% of the corridors were feasible, for a cage with 18 mm of anterior posterior size, only 28% of the corridors were feasible, and for the 20mm cage, only 15% of the corridors were feasible. Conclusion: The present study demonstrates that placing the patient in a right decubitus does not exert significant influence over the OLIF safe corridor when compared to the corridor seen in the dorsal MRI. Thus, suggesting that it is safe to trust in the dorsal MRI to assess the viability of performing the OLIF technique. Furthermore, the study shows that, only 28% of the corridors would allow the placement of a cage with 18 mm anterior posterior size, and only 15% would allow a 20mm cage, without increasing the corridor size with a retraction of the psoas muscle. Rafael Barreto Silva 1 , Carlos Andres Amelunge Rodriguez 1 , Jose Carlos Barbi Goncalves 1 , Luís Eduardo De Lábio Parra 1 , Alexandre Jaccard 1 , Ricardo Acacio Dos Santos 1 , Gabriel Pokorny 1 1 Instituto da Coluna Campinas, Campinas / São Paulo, Brazil Introduction: In an attempt to find an ideal entry point for each patient, some authors have proposed the use of preoperative CT or MRI scans to identify the location of the retroperitoneal structures and then assess how horizontal a lateral access could be. However, one of the main difficulties with this analysis is that the retroperitoneal structures move to a more anterior position, between the dorsal position (CT or MRI position) and the prone position (surgical position). The aim of this study is therefore to analyze the position of the retroperitoneal structures and their movement using MRI in prone and dorsal decubitus, as well as to verify the theoretical risk of retroperitoneal injury at each of the following entry points. Material and Methods: Cross-sectional observational, comparative, non-randomized study. The inclusion criteria was as follows, Patients over the age of 18, who have consented to take part in the study by filling in the free consent form, and who have no medical contraindications to undergoing on MRI. And the exclusion criteria was patients with any pathology that makes it impossible to take the measurements proposed in the study. Patients who, for whatever reason, have a low-quality image exams. The risk of violation of peritoneal content was assessed both in dorsal and ventral decubitus from two different starting points (red line and green line). Data was compiled in a spreadsheet and analyzed using R software. Categorical variables were described as count and percentage. To compare the impact of different entry points in the risk of peritoneal violation a generalized linear mixed model with binomial distribution family was built. To compare the contrasts and obtain estimations of the odds of peritoneal violation, the estimated marginal means contrasts were analyzed. P values lower than 0.05 were deemed significant. Results: 28 patients were included in the work, of those 16 were female (57%), with the mean age of 39 years old. The risk of peritoneal violation in the “red line” approach was significantly greater than the risk of peritoneal violation in the “green line” approach, showing significant difference in every studied level, both in ventral as in dorsal decubitus. The probability estimated by model of peritoneal violation in ventral decubitus (DV) for the “green line” in L1L2 was 5% (1% - 13%), while for the “red line” the estimative was around 83% (68% - 92%), p < 0.0001. Similarly, in the L2L3 level, the “green line” approach had an 1% (0.3% - 3%) risk of peritoneal violation, compared to 53% (33% - 77%) form the “red line”, p < 0.0001. Furthermore, similar discrepancies were noted in L3L4 (0.3% vs. 23%) and L4L5 (0.6% - 38%). Conclusion: The use of the “red line” approach led to a high risk of peritoneal violation, even in the ventral decubitus. On the other hand, the use of the “green line” entry point, led to diminutive risks of violation in the ventral decubitus with estimated probability of peritoneal violation smaller than 2% for every level below L1-L2. Sebastián Vial Juillerat 1,2 , Dennys Gonzales 2 , Andrea Contreras Alfaro 1 1 Universidad de Chile, Santiago, Chile , 2 Instituto Traumatológico dr. Teodoro Gebauer, Santiago, Chile Introduction: Pedicle screw loosening remains one of the most common complications associated with spinal instrumentation. It is influenced by multiple factors, with a prevalence ranging from less than 1% to 15% in non-osteoporotic patients and exceeding 60% in cases of osteoporosis. Despite its prevalence, the definition of pedicle screw loosening varies across different studies. The primary objective of this study is to determine the interobserver agreement in the imaging diagnosis of pedicle screw loosening and the measurement of Hounsfield Units (HU) on computed tomography (CT) scans. A secondary objective is to establish associations between the measured variables and pedicle screw loosening. Material and Methods: A cross-sectional study was conducted, collecting clinical and imaging variables from thoracolumbar CT scans taken between May 2023 and April 2024 in patients who underwent surgery for degenerative spine pathology. Interobserver agreement was assessed by comparing the results of a musculoskeletal radiologist, a spine surgeon with over 5 years of experience, a spine surgery fellow, and an orthopedic and trauma surgery resident. Krippendorff's alpha test was used to assess interobserver reliability. For associations between variables and screw loosening, descriptive statistics were performed, and chi-square tests and t-tests were used for comparison of means. Data analysis was carried out using JASP and SPSS software. Results: A total of 95 participants were included in the study, 20 of whom were diagnosed with pedicle screw loosening. The majority were male, with an average age between 61 and 65 years. The level of interobserver agreement for screw loosening was 0.71 (95%CI: 0.59-0.80) and 0.58 (95%CI: 0.45-0.69) for Hounsfield Units. However, when excluding the observer with the least experience, the agreement scores increased to 0.80 and 0.78, respectively. Statistically significant associations were found between screw loosening and the number of operated levels, as well as the presence of pseudoarthrosis. The group of patients with screw loosening exhibited a lower average HU (129 ± 53 vs. 150 ± 48), although this difference was not statistically significant. Conclusion: Our study is the first to evaluate multidisciplinary interobserver agreement in the diagnosis of pedicle screw loosening. It demonstrates that the experience level of observers significantly impacts the evaluation of imaging variables, with an improvement in agreement when the least experienced observer is excluded. Additionally, associations were found between screw loosening and variables such as fused levels, Hounsfield Units, and the presence of pseudoarthrosis, which are also described in the international literature.

Elie Najjar 1 , Ahmed Hassan 1,2 , Weronika Nocun 1 , Nasir Quraishi 1 1 Queen's Medical Centre, Nottingham University Hospitals, Nottingham, United Kingdom , 2 Department of Orthopedics and Trauma Surgery, Assiut University School of Medicine, Assiut, Egypt Background: Lean methodology, inspired by Toyota’s production system, aims at improving performance, more specifically quality and profitability through reducing time and resources spent on non-value-added tasks. Such principles are increasingly being applied to health services to identify the least wasteful way to provide better and safer patient care with less delays. Yet only few studies have discussed the use of lean principles in spine surgery. Objective: To systematically evaluate the relevant literature regarding the use of lean principles in the operating room for spinal surgery. Methodology: A systematic review of the English language literature dating up until June 2023 was undertaken. The search criteria (‘Lean’ and ‘Spine’ or ‘Spinal’ or ‘Neurosurgery’) were used with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Results: Of a total of 193 articles, 4 studies used Lean principles in a total of 220 spinal surgery patients. All were retrospective case studies. Lunardini et al (2014), audited their use of spinal instrumentation in 38 surgical cases and found that 41% of the instruments could be removed from the trays, without compromising the surgery. This amounted to projected cost savings of $41,000 annually. Cawley et al (2020), applied the lean principles to optimize the use of intraoperative navigation in 20 cases of Adolescent Idiopathic Scoliosis Surgeries. Optimising accuracy (of the images) was the biggest factor influencing repeat intraoperative scans and this was reliant on incremental changes to the operative setup and techniques. Sethi et al (2022), measured costs across entire episodes of care for 157 spinal patients using time-driven activity-based costing (TDABC), in combination with lean methodology. Inpatient stays were 1-3 days and they reported that those discharged on post-operative day 3, had statistically significantly more time spent with medical/nursing staff, than those going home on day 2 and day 1 (who had the least). The study by Liu et al (2018), was the only intra-operative study of Lean methodologies in 5 spinal patients. Their assessment showed significant temporal variabilities in duration of the different surgical steps (decompression vs closure and hardware vs closure were significantly different, p = 0.003). Variability in procedural step duration was smallest for closure and largest for exposure. Waste was predominantly from waiting (14.8%), overprocessing (18.8%) and instrument defects (66%). Conclusion: The use of Lean methodology in operating room for spinal surgery, allows standardisation of surgical steps and can improve patient outcomes, reduce costs, and lead to higher value healthcare. Michael Tawil 1 , Marc Prablek 1 , Timothy Yee 1 , Anthony di Giorgio 1 , Alysha Jamieson 1 , Vivian Le 1 , Domagoj Coric 2 , Eric Potts 3 , Erica Bisson 4 , John Knightly 5 , Kai-Ming Fu 6 , Kevin Foley 7 , Mark Shaffrey 8 , Mohamad Bydon 9 , Dean Chou 10 , Andrew Chan 10 , Scott Meyer 5 , Anthony Asher 2 , Christopher Shaffrey 11 , Jonathan Slotkin 12 , Michael Wang 13 , Regis Haid 14 , Steven Glassman 15 , Paul Park 6 , Michael Virk 6 , Praveen Mummaneni 1 1 University of California, San Francisco, San Francisco, United States, 2 CNSA, Charlotte, United States, 3 Goodman Campbell brain and spine, Carmel, United States, 4 University of Utah, Salt Lake City, United States, 5 Maxim Spine, Cedar Knolls, United States, 6 Cornell, New York, United States, 7 Semmes Murphey, Memphis, United States, 8 University of Virginia, Charlottesville, United States, 9 Mayo, Rochester, United States, 10 Columbia University, New York, United States, 11 Duke, Durham, United States, 12 Geisinger, Danville, United States, 13 University of Miami, Miami, United States, 14 Atlanta Brain and Spine, Atlanta, United States, 15 Norton, Louisville, United States Introduction: Previous studies have suggested regional variation in disability after surgery for lumbar spondylolisthesis. However, long-term data regarding this geographic variability after PLIF or TLIF has not been well described. Material and Methods: We analyzed patients with lumbar grade 1 spondylolisthesis undergoing PLIF/TLIF from the 12 highest enrolling sites in the prospective Quality Outcomes Database. We analyzed baseline and 60-month postoperative outcomes. Differences in demographics, comorbidities, and ODI were compared across geographic regions of the United States with univariate and multivariate methods. Results: Among the 608 patients who underwent surgery for grade 1 lumbar spondylolisthesis across 12 surgical sites, 385 underwent P/TLIF. Baseline and 60-month ODI values were available for 310 (80.5%). By geographic region, the Northeast had 15 patients across 3 centers, the West had 39 patients across 2 centers, the Midwest had 58 patients across 2 centers, and the South had 198 patients across 5 centers. Patients in the South tended to be younger, have higher BMI, have higher rates of coronary artery disease, have lower rates of at least college-level education, and have significantly worse mean ± SD ODI at baseline (51.3 ± 14.5) compared to the Northeast (44.7 ± 18.7), West (43.9 ± 15.4), and Midwest (40.9 ± 16.0) (p < 0.001). Patients in the South had the largest 60-month improvement in mean ± SD ODI (25.9 ± 20.5), followed by the Midwest (21.2 ± 17.1), the Northeast (20.9 ± 24.0), and the West (13.3 ± 22.9) (p = 0.004). This resulted in similar 60-month ODI values across regions. Region did not predict baseline, change, or 60-month ODI scores in multivariate regression. Conclusion: Among patients undergoing P/TLIF for grade 1 lumbar spondylolisthesis, those residing in the Southern United States had the worst disability at baseline but improved to a greater degree than other regions, resulting in similar 60-month ODI scores across all geographic regions. Michael Tawil 1 , Marc Prablek 1 , Anthony di Giorgio 1 , Nima Alan 1 , Sammer Zammar 1 , Dean Chou 2 , Christopher Shaffrey 3 , Oren Gottfried 3 , Erica Bisson 4 , Anthony Asher 5 , Domagoj Coric 5 , Eric Potts 6 , Kevin Foley 7 , Michael Wang 8 , Kai-Ming Fu 9 , Michael Virk 9 , John Knightly 10 , Scott Meyer 10 , Paul Park 9 , Cheerag Upadhyaya 11 , Mark Shaffrey 12 , Luis Tumialan 13 , Jay Turner 13 , Regis Haid 14 , Mohamad Bydon 15 , Juan Uribe 13 , Praveen Mummaneni 1 1 University of California, San Francisco, San Francisco, United States, 2 Columbia University, New York, New York, United States, 3 Duke, Durham, United States, 4 University of Utah, Salt Lake City, United States, 5 CNSA, Charlotte, United States, 6 Goodman Campbell brain and spine, Carmel, United States, 7 Semmes Murphey, Memphis, United States, 8 University of Miami, Miami, United States, 9 Cornell, New York, New York, United States, 10 Maxim Spine, Cedar Knolls, United States, 11 UNC, Chapel Hill, United States, 12 University of Virginia, Charlottesville, United States, 13 Barrow, Phoenix, United States, 14 Atlanta Brain and Spine, Atlanta, United States, 15 Mayo, Rochester, United States Introduction: In the United States, there is regional variations in the outcomes of spine surgery for various pathologies. Here we study the regional variation in patients who underwent anterior cervical discectomy and fusion (ACDF) for cervical spondylotic myelopathy (CSM). Material and Methods: We queried the Quality Outcomes Database from the 14 highest enrolling sites for patients diagnosed with CSM and underwent 1, 2, or 3-level ACDF. Our primary outcome measure to assess regional variation was the minimal clinically important difference (MCID) in patient-reported outcomes (PROs), including neck disability index (NDI) and EuroQol 5 Dimension 5 (EQ-5D) scores at baseline and 24 months postoperatively. Results: Among the 1141 patients that underwent surgery for CSM, 396 patients underwent a 1, 2, or 3 level ACDF with baseline and 24-month PROs available. The number of patients per region included: Northeast (n = 61), South (n = 154), Midwest (n = 114), and West (n = 67). For the entire cohort, there were no statistical differences in regional variations for the percentage of patients who achieved MCID for NDI (p = 0.121) or EQ-5D (p = 0.257). In subanalysis of patients who underwent 1-level ACDFs (n = 170), the Midwest had the highest percentage of patients who achieved MCID for NDI (83.3%), followed by the Northeast with 23 patients (76.7%), the West with 14 patients (53.8%), and the South with 32 patients (53.3%) (p = 0.002). No difference was found in the percentage of patients achieving MCID for EQ-5D (p = 0.331). In multivariate regression, region was not predictive of achieving MCID for NDI (p > 0.05). In similar subanalyses in patients who underwent 2- level, or 3-level ACDF there were no significant regional variations in MCID for NDI or EQ-5D. Conclusion: In the United States, there is no difference in outcomes among regions for patients undergoing a 1, 2 or 3 level ACDF. Karen Weissmann 1 , Francoise Descazeaux 1 1 Patagonia Spine Foundation, Santiago, Chile Introduction: The representation of women in the Orthopedics and Traumatology society in our country is 14.4%, while in the Spine Committee it is 4.3%. The perception of treatment has been studied in other countries but not in ours. Materials and Methods: A survey was conducted among spine surgeons and female orthopedic surgeons in our country. All participants were asked, “Do you think women are treated as equals by the fraternity?” Men were additionally asked, “How would you characterize your relationship with your female colleagues?” and women were asked, “How do you think your male colleagues characterize their relationship with you?” The survey was distributed via the social network WhatsApp. Results: 56 men and 96 women responded to the survey. For the first question 87% of men and 37.6% of women responded affirmatively. Regarding the characterization of relationships, men responded that 43.6% consider their female colleagues as just another colleague, 25.6% have no female colleagues on their team, 15.4% view them as friends, 9.0% as mentors, 2.6% as sisters, 2.6% as secretaries, and 1.3% as disciples. Women reported feeling that men perceive them as friends (46.9%), responsible wives (36.5%), gender-neutral colleagues (27.1%), younger sisters (17.7%), 15.6% as either rockstars, older sisters, or mothers mothers of adolescente childrend; 13.5% though of them as studious colleagues or executive wives; 7.3% felt they where being characterized as annoying wives or hysterical mothers; 6.3% felt as art school teachers; 6.3% as seductresses; 5.2% as a mother of toddlers; 3.1% as either a servants or a math teacher and 1% felt they where tretaed as unconditional lovers. Conclusion: Female spine surgeons are still underrepresented in scientific societies. There is a severe disparity between male and female spine surgeon’s perceptions of their relationships in working teams; which may hinder communication between them. Ayush Sharma 1 1 Dr BR Ambedkar Memorial Hospital, Spine Surgery, Mumbai, India Background: The economic burden of loss of productivity due to chronic lumbar degenerative disorders is enormous. Surgical management of these chronic disorders is proven to reduce disability and improve quality of life in most patients. Minimally invasive spine surgery (MIS) offers distinct advantages in terms of less tissue trauma and consequently can lead to quicker recovery. The aim of the current narrative review was to assess the effect of minimally invasive approach on return to work after elective lumbar surgery. Methods: The current study is a narrative literature review of the studies comparing time taken for return to work among open vs MIS approaches. Studies in the time duration (2004-2024) focusing only the lumbar spine, and procedures ranging from 1-2 level discectomies, decompression and lumbar fusion were included in the review. Results: Out of 21 studies assessed, eight studies directly compared open lumbar fusion with MIS lumbar fusion. Six studies reported quicker return to work for MIS lumbar fusion and endoscopic discectomy. Two studies did not report any significant difference between MIS and open approach. Studies assessing endoscopic decompression and discectomies report time to return to work to be as short as 5-11 days post-surgery. Conclusion: There is inadequate evidence to clearly establish the superiority of MIS approach over open technique in time to return to recovery. Some studies point towards sooner return to recovery among patients undergoing MIS lumbar fusion compared to open fusion. Endoscopic decompression and discectomies provide promising results for a short return to recovery time duration. Ari Halpern 1,2 , Gabriely Rangel 1 , Marina Siqueira 1 , Marilia Navarro 1 , Lucas Correa 1 , Carlos Tucci 1,3 1 Hospital Israelita Albert Einstein, CEPPS - Centro de Estudos e Promoção de Políticas em Saúde, São Paulo, Brazil , 2 HCFMUSP, Reumatologia, São Paulo, Brazil , 3 Sociedade Brasileira de Coluna, Comissão de Políticas em Saúde, São Paulo, Brazil Spine-related conditions (SRC) are increasingly prevalent and pose a major challenge to the universal Brazilian healthcare system (SUS) due to their high direct and indirect costs, coupled with a low awareness and absence of specific policies. Most cases of routine back pain are typically a benign, self-limiting condition that does not require imaging. However, there is ongoing confusion and inconsistency regarding the appropriate use of imaging for back pain patients. Unnecessary imaging can result in higher healthcare costs, expose patients to avoidable radiation, and lead to potentially unnecessary treatments. To date, only a few studies with heterogeneous methodologies have addressed SRC inpatient and outpatient costs within SUS. The aim of this paper is to estimate and evaluate SUS outpatient total and categorized costs in 2014 and 2023 years. Material and Methods: A top-down cost of illness study, in 2014 and 2023 years was performed, with data extracted from SUS outpatient database (SIA-SUS), based on SRC ICD-10. An additional and complementary analysis based on SUS coding specific SRC procedures list (SIGTAP) to fulfill ICD input in patients’ records was performed since only about 30.8% of the records had ICDs filled in. This two steps data extraction method aimed to provide a more comprehensive, specific, and standardized approach. Some outpatient procedures, like specialized consultations, need the ICD input to identify the type of consultation. Since only 30.8% of records include this code, we extrapolated the approved value of the procedures to capture others SRC records that lack ICD inputs. All data costs were summed up and updated to inflation-adjusted and currency values to estimate SRC outpatient direct costs. Results: Total SRC outpatient direct costs in SUS summed USD 127.9 million in 2014 and USD 123,3 million in 2023 that represent respectively 15.4 and 18.1 million procedures. Of this total, in 2023 USD 82.3 million (64.4%) were attributable to diagnostic procedures, USD 45.0 million (35.2%) to clinical procedures, USD 309.3 thousand (0.2%) to orthoses, prostheses and special materials, and USD 255.8 thousand (0.2%) to complementary actions such as remuneration for travel compensation. Interestingly, the percentage of costs related to diagnostic procedures such as X-rays, CT scans, and MRI increased about 17%, between 2014 and 2023. Conclusion: The present study confirms the high burden of SRC to SUS with a total USD 123,3 million in 2023 (BRL 624.7 million). Despite its great importance, the recording of spine-related conditions (SRC) in the SUS databases is still very inconsistent, as evidenced by the high frequency of unspecified ICD codes. Despite extensive scientific evidence against the use of imaging in most cases of spine-related issues, spending on imaging exams increased from 2014 to 2023 and now represents the largest portion of outpatient care costs for SRC. While the findings suggest that a new methodology may be needed to ensure a more comprehensive, specific, and standardized approach, further investigation in future studies is warranted. Carlos Tucci 1 , Marina Siqueira 1 , Gabriely Rangel 1 , Ari Halpern 1 , Marilia Navarro 1 , Lucas Correa 1 1 Hospital Israelita Albert Einstein, CEPPS - Centro de Estudos e Promoção de Políticas em Saúde, São Paulo, Brazil Introduction: In a country of continental dimensions and complex inequalities, with great reliance on the public health system (SUS), the availability of information systems with reliable and complete data is a great ally to qualify the healthcare provided and the health system management. Among the procedures covered by SUS, osteomuscular surgeries play a relevant role in terms of volume, reimbursement costs, and impact on patients' lives. In this context, this study assesses the proportion and territorial distribution of osteomuscular surgeries within SUS’ outpatient information system (SIA) with no registry of the associated primary condition (ICD-10), and the changes in this registration in the last decade. The outpatient focus is justified because while coding the main diagnosis is mandatory in the hospital information system (SIH) the same does not apply to SIA. We also analyze pertinent hospital procedures (SIH) with low specificity. Methods: This descriptive-exploratory study used publicly available data to analyze the non-completion of associated conditions (ICD-10) among osteomuscular surgeries (SIA), and the low specificity of procedures related to the osteomuscular specialty (SIH). Results: In 2023, 192.678 osteomuscular surgeries were registered within SIA, of which, 571 (0.3%) had no ICD-10. Compared to the other seventeen surgical specialties provided by SUS, this is one of the lowest levels of non-completion, only behind oncological and neurological surgeries (with no procedure without an ICD-10), and contrasting to the circulatory system and oral-maxillofacial surgeries (with more than 90% of procedures without an ICD-10). A great improvement in this completion has been observed in the last decade. Of the 399,004 outpatient osteomuscular surgeries performed in 2014, 9.9% had no ICD-10 information. Considering the osteomuscular surgeries by Brazilian region, the regional disparities in the proportion of procedures with no ICD-10 information were much more accentuated in 2014 (varying from 20,3% in the Mid-Weast to 7,2% in the Southeast) when compared to 2023 (from 0.4% in Southeast to 0.1% in South). An additional point of attention concerns multiple and sequential procedures in orthopedics and polytrauma, not allowing the identification of which specific procedures were performed together. Such procedures are performed only in hospitals (SIH), but their numbers are significant and growing in SUS: 58,400 procedures with a total value of R$208.3 million in 2014 vs. 100,727 procedures and R$334.5 million in 2023. Conclusion: The results highlight improvements in the registry of osteomuscular outpatient surgeries. However, while other surgical specialties have shown that it is possible to attain informed ICD-10 for all procedures, a non-negligible number of osteomuscular surgeries are still performed with no information regarding the primary condition. Better incentives for a complete registration, such as training health professionals responsible for data collection, or the completeness of registries being a requisite for SUS payment, are worth discussing among policymakers, especially in regions with worsening tendencies or the highest levels of no ICD-10 registration. Another gap refers to the increasing number of sequential/multiple hospital procedures. Although not representing data incompleteness within SIH, they indicate the need for greater specificity in coding procedures covered by the SUS. Alisson R. Teles 1 , Antonio Gutemberg Martins 1 , Guilherme Ludwig 1 , Maiara Anschau Floriani 1 , Paulo Worm 1 , Albert Brasil 1 1 Hospital São José - Santa Casa de Porto Alegre, Porto Alegre, Brazil Objective: To evaluate the impact of healthcare system on clinical outcomes after spine surgery in Brazil. Methods: Retrospective review of prospectively collected data as part of our institutional spine clinical registry. All patients undergoing spine surgery for degenerative disease of the cervical or lumbar spine were included. Treatment was performed by the same surgical group, in the same hospital, for patients in the public and private healthcare systems. Baseline, perioperative, 3 months and 1 year after surgery data were collected using a standard protocol. Bivariate and multivariate statistics were performed using SPSS. Results: A total of 904 patients were included: 288 SUS / 616 private. There were 186 cervical and 718 lumbar cases. In general, 48.5% were female, mean age was 52.6 (±14.9), mean BMI 27.4 (±4.37), 12.8% were smokers, and 12.1% had previous spine surgery. Baseline features of the sample suggest that severity of disease at presentation is different according to healthcare system: patients in the public sector presented with higher percentage of myelopathy for cervical cases (70.5% x 47%, p = 0.003) and radicular deficit for lumbar cases (42.7% x 28.8%, p < 0.001). At baseline, SUS patients presented with higher axial pain, disability and anxiety (p < 0.001) compared to private patients. Access to surgical care was also different between the groups, with SUS patients presenting longer duration of symptoms and more severe myelopathy scores. No difference in perioperative variables (surgical technique, diagnosis, surgical timing, blood loos, number of levels, complications) were observed between the groups. In general, surgery significantly improved pain, disability and quality of life in patients in the public and private healthcare system (p < 0.001). Public healthcare system patients presented significantly less improvement in quality of life (mean difference in PC-SF36 6.23 x 13.7; MC-SF36 6.29 x 14.5), pain (mean difference NRS back -1.07 x -3.68; NRS radicular -1.47 x -4.24), and disability (mean difference ODI -15.3 x -28.9; NDI -6.2 x -18.5) in comparison with private patients. At 1 year follow-up 33.1% of SUS patients were on disability benefits in comparison with 6.5% in the private group (p < 0.001). At 3 months follow-up, 89.5% were satisfied with treatment (no difference between the groups) and 84.9% at 1 year after surgery (88.4% x 78.4%, p = 0.005). Logistic regression model with predictors for satisfaction at 1 year follow-up identified SUS as an independent predictor of dissatisfaction (B = -0.84, Adjusted OR = 0.42, CI95% 0.23 - 0.77, p = 0.005). Conclusion: Healthcare system impacts PROMs after spine surgery for degenerative disease in Brazil. After controlling for baseline confounders, SUS was associated with 58% less likelihood of satisfaction after spine surgery. Non-medical social determinants of health play a major role on the clinical outcomes of spine surgery for degenerative disease in Brazil. Alisson R. Teles 1 , Guilherme Ludwig 1 , Antonio Gutemberg Martins 1 , Maiara Anschau Floriani 1 , João Roth 1 , Albert Brasil 1 1 Hospital São José - Santa Casa de Porto Alegre, Porto Alegre, Brazil Objective: The impact of anesthetic technique on spine surgery outcome is controversial. General anesthesia (GA) is the most commonly used anesthetic technique when performing lumbar spine surgeries. However, some centers have reported improved outcomes employing regional anesthesia (RA) techniques as part of an enhanced recovery after surgery protocol. The objective of this study was to compare the outcomes of general and regional anesthesia in patients undergoing lumbar decompression in the same hospital. Methods: Retrospective review of prospectively collected data of patients selected for lumbar decompression for stenosis or disc herniation. Inclusion criteria: unilateral decompression, single-level, and no previous lumbar spine surgery. Baseline features, surgical data, and patient reported outcome measures (PROMs = ODI, EQ5D, NRS of pain, satisfaction) were collected at baseline and during follow-up as part of the institutional spine clinical registry. All patients underwent lumbar decompression using minimally invasive tubular approach by the same surgeon. RA protocol consisted of spinal anesthesia with bupivacaine and sedation with propofol as needed. Total direct cost was also collected. Statistical analyses were performed using SPSS. Results: 39 patients were included: 25 in the GA and 14 in the RA group. Baseline features and PROMs were similar between the groups. In general, 51.3% were female, mean age was 47.7years (±13.0), mean was BMI 27.2 (±4.17), 68.3% had disc herniation and 31.7% stenosis. Length of hospital stay was 24h in 7.8%, with no difference between the groups. Estimated blood loos and surgical time were similar between the groups. There was no intra-operative complication, no readmission or reoperation within 3 months after surgery in this cohort. No patient had urinary retention in this series. Pain scores during recovery room were similar between the groups. The incidence of nausea/vomiting was similar between the groups (RA = 14.3%, GA = 18.5%, p = 0.73). At follow-up, pain scores (NRS back and leg), disability (ODI) and quality of life scores (EQ5D) were similar between the groups. No statistically significant difference in total hospital cost was observed between the groups (mean hospital cost R$3247 ±1488). Conclusion: Our initial experience shows that regional anesthesia is well tolerated in this group of patients. No difference in the main outcomes of lumbar decompression were observed using GA and RA. Anna Gorbacheva 1 , Angela Kantor 1 , Clifford Pierre 1,2 , Julius Gerstmeyer 1,2,3 , Donald Davis 1,2 , Mark Kraemer 1,2 , Nicholas Minissale 1,2 , Tara Heffernan 1 , Luke Jouppi 1,2 , Cameron Hogsett 1,2 , Colin Gold 1,2 , Amir Abdul-Jabbar 1,2 , Rod Oskouian 1,2 , Jens Chapman 1,2 1 Seattle Science Foundation, Seattle, United States , 2 Swedish Neuroscience Institute, Seattle, United States , 3 Ruhr University Bochum, BG University Hospital Bergmannsheil, Department of General and Trauma Surgery, Bochum, Germany Introduction: Sacroiliac joint (SIJ) fixations have emerged as treatment for symptomatic SIJ dysfunction (SIJD) when conservative measures have failed. Over time, SIJ fixation SIJF) techniques have evolved into less invasive and more biomechanically diverse applications. Through our bibliometric analysis, we investigate the progression of SIJF as a whole over time, with special focus on indications and techniques as expressed in publications, citations, publishing countries, authors, keywords, and topics. Methods: The Web of Science (WoS) database was used to retrieve articles on July 26, 2024 from the time period January 1, 1982 to July 26, 2024 with the search terms “SI Joint Fusion” OR “Sacroiliac Joint Fusion” OR “SI Joint Fixation” OR “Sacroiliac Joint Fixation” OR “SI Joint Stabilization” OR “Sacroiliac Joint Stabilization” OR (“SIJF” AND “spine surgery”). Using Excel, we created the citation and publication trend analyses. VosViewer™ was used to generate network visualization diagrams. Results: We found two-hundred fifty articles with a notable increase in yearly publications starting in 2013 and peaking in 2022 with 50 publications. In corollary fashion, there was an increase in citations that crested in 2022 with 492 citations. Co-occurrences of key terms cited in studies remained consistent, in linking with diagnosis and treatment of SIJD as seen during 2019-2023. Conclusion: This comprehensive bibliometric analysis on SIJ fixations offers insights into the evolving landscape of research, authorship, and publication trends of this more recently introduced clinical entity and surgical management strategy. Increased clinical and industry focus has been accompanied by a substantial rise of scientific publications on this subject matter. Daryll Dykes 1 , Jill Ruppenkamp 1 , Katherine Corso 1 , Caroline Smith 1 , Michelle Costa 1 1 Johnson & Johnson, Raynham, United States Introduction: A 2007 meta-analysis of cervical fusion outcomes reported fusion rates of 89.5%. Despite innovation, there is no evidence to suggest improved fusion rates since that study. Our study evaluated the two-year healthcare utilization associated with cervical fusion surgery using contemporary data. Material and Methods: Patients with cervical-only fusion surgery between October 2015 and December 2020 and ≥ two years continuous enrollment post-surgery in the Merative MarketScan Commercial Claims database were identified. Outcomes included two-year complication and reoperations rates, and costs. Variables included patient demographics, index surgery approach, number of levels fused and instrumentation use. Descriptive analytics were conducted for all outcomes. Healthcare costs were adjusted to 2022 inflation and analyzed using generalized linear models. Results: 28,674 patients with average age 51, including 53% females, were identified in the database. Half of all patients were treated in the inpatient setting, 40% in outpatient, and 10% in ambulatory surgical care. The average Elixhauser index patient comorbidity score was 1.6 (standard deviation (SD): 1.5) and nearly 24% patients had ≥ 3 comorbidities. Obesity and diabetes affected 14% and 16% cases, respectively. Degenerative disc disease (DDD) and deformity were diagnosed in 87% and 8% cases, respectively, and 58% cases had two or more levels fused. At 2-year follow-up, new cervical operations affected 12% cases, but only one third of those cases had a diagnosis of spinal fusion complication at the time of the new procedure. Pseudarthrosis was reported in 6% cases, and infection in 2.2% cases. Healthcare costs associated with pseudoarthrosis or infection, without reoperation, averaged $33,055 (95% confidence interval (CI): $24,514-$51,596) and $108,173 (95%CI: $86,890-$129,455), respectively. When reoperations were performed, costs increased by $49,354 (95%CI: $39,113-$59,596). Conclusion: By 2-year post-operative, 12% patients with cervical fusion underwent additional cervical surgery, suggesting outcomes consistent with those reported in the 2007 meta-analysis. Daryll Dykes 1 , Jill Ruppenkamp 1 , Katherine Corso 1 , Caroline Smith 1 , Michelle Costa 1 1 Johnson & Johnson, Raynham, United States Introduction: Spinal lumbar fusion has been associated with high revision rates. Our study evaluated the two-year healthcare utilization associated with lumbar fusion surgery using comprehensive, contemporary data. Methods : Patients with lumbar-only fusion surgery between October 2015 to December 2020 and ≥ two years continuous enrollment post-surgery in the Merative MarketScan Commercial Claims database covering > 100 million lives were identified. Outcomes included two-year follow-up for: reoperations with diagnoses of spinal complications; any new spinal surgery; healthcare costs; and costs associated with pseudarthrosis and infection. Exploratory outcomes included discharge disposition and post-operative filled prescription use. Variables included patient demographics, index surgery approach, number of levels fused and instrumentation use. Descriptive analytics were conducted for all outcomes. Healthcare costs were adjusted to 2022 inflation and analyzed using generalized linear models. Results: 14,527 patients with average age 52, including 56% females, were included in the analysis. The majority were treated in the inpatient setting (88%, hospital outpatient: 7%, ambulatory surgical care: 5%). The average Elixhauser index patient comorbidity score was 1.8 (standard deviation (SD): 1.6) and ∼ 30% patients had ≥ 3 comorbidities. Diabetes affected 17% cases. Degenerative disc disease and deformity were diagnosed in 88.3% and 16.6% cases, respectively. One-level fusion was performed in 67% cases. At 2-year follow-up, new lumbar operations were performed in 11% cases, of which 57% had a diagnosis of spinal fusion complication at the time of the new lumbar procedure. Pseudarthrosis and infection were reported in 6% and 4% of all cases, respectively. Healthcare costs associated with pseudoarthrosis and infection, without reoperation costs, averaged $32,302 (95% confidence interval (CI): $20,773-$43,831) and $80,539 (95%CI: $61,270-$99,807), respectively. When reoperations were performed, costs increased by $73,603 (95%CI: $57,519-$89,688). Conclusion: For > 10% of patients, lumbar spinal surgery is associated with additional lumbar surgical interventions and high overall healthcare costs. Reoperation costs exceeded $70K. Ramkumar Mohan 1 , Joanne Fang Nian Lim 1 , Eunice Wilianto 1 , Andrew Wu Guan Ru 1 , Jacob Oh 1 1 Tan Tock Seng Hospital, Singapore, Singapore Introduction: With the recent push for Enhanced Recovery After Surgery (ERAS) pathways in Spine surgery, it has become increasingly important for early identification of patients who will need step down care post operatively. Our study team aims to create a tiered scoring system to stratify and identify patients pre-operatively for step down rehabilitation facility admission , thereby reducing waiting time for placement to such institutions, length of stay in acute hospitals and overall healthcare costs. We aim to do this by initially identifying independent predictive factors for Community hospital admission based on patients in our institution who underwent single or double level lumbar spinal fusion procedures. Material and Methods: Our study included 83 patients from January 2021 to June 2022. A multivariate generalized logistic regression model was initially constructed using clinically relevant variables believed to influence the decision to discharge patients either to home or a community hospital for rehabilitation following spinal surgery. To refine the model, a bidirectional stepwise selection process based on the Akaike Information Criterion (AIC) was employed. The final model retained the variables with the strongest association with the discharge destination. Results: In the univariate analysis, significant findings included the use of walking aids pre-operatively (odds ratio [OR] = 5.100, p = 0.022). Additionally, while age over 65 years showed a trend towards significance (OR = 7.500, p = 0.063), it did not reach statistical significance. In the multivariate analysis, age over 65 years was significantly associated with increased odds of admission (p = 0.0371), as were lower Visual Analogue pain Scores (VAS) (p = 0.001). The use of walking aids, while significant in univariate analysis, showed a non-significant association in multivariate analysis (p = 0.6213). Pre-operative weakness approached significance (p = 0.0916), suggesting its importance as a predictor. Conclusion: Our study team has identified lower pre operative VAS and higher age as independent risk factors for step down rehabilitation facility admission. We aim to include further pre and post operative variables and larger cohort size to refine our tier based predictive tool. As well as further studies for prospective validation for the use of this tool in clinical practice. We believe that these tools will allow clinicians to identify patients in need of such step down care early, in the pre-operative or immediate post-operative period and thereby facilitate careful patient selection for ERAS pathways. Markian Pahuta 1 , Mohamed Sarraj 2 , Nicolas Dea 3 , Nathan Evaniew 4 , Greg McIntosh 5 , Daipayan Guha 6 1 McMaster University, Orthopaedic Surgery, Health Research Methods, Evidence, Impact, Hamilton, Canada , 2 McMaster University, Orthopaedic Surgery, Hamilton, Canada , 3 University of British Columbia, Spine Surgery , Vancouver, Canada , 4 University of Calgary, Orthopaedic Surgery, Calgary, Canada , 5 Canadian Spine Outcomes Research Network, Markdale, Canada , 6 McMaster University, Neurosurgery, Hamilton, Canada Introduction: Degenerative Cervical Myelopathy (DCM) is a debilitating condition and current recommendations encourage shared decision-making (SDM) between surgeons and patients. SDM is a process in which clinicians and patients jointly deliberate possible options on treatment and related risks so that the patient is well informed and makes a decision aligned with their preferences. A potential barrier to the implementation of SDM in Degenerative Cervical Myelopathy is physicians’ perception of understanding DCM patients’ values and preferences. Our objective was to quantify the importance of factors that may drive physicians’ treatment decisions for DCM. Material and Methods: Using snowball sampling, spinal surgeons and family physicians were recruited from across Canada. Demographic and practice information were collected. Participants then completed an online discrete-choice experiment survey. In a series of 10 questions, respondents chose between two hypothetical health states defined in terms of five attributes, or “decision factors”: (i) upper extremity neurologic function, (ii) lower extremity neurologic function, (iii) risk of cervical spine surgery, (iv) dysphagia, and (v) C5 palsy. Participants were asked to choose which ‘life’ they preferred, and a regression model was used to quantify the importance of each decision factor. Results: Fifty family physicians and fifty spinal surgeons participated in this study. For family doctors, the rank order of decision factor importance was: lower extremity neurologic function > upper extremity neurologic function > dysphagia > >C5 palsy > risk of revision surgery. Whereas for spinal surgeons, upper and lower extremity neurologic function were equally important and weighed more highly than dysphagia. Notably, C5 palsy and risk of revision surgery were not considered important decision factors by spinal surgeons. Other than revision surgery, surgeons valued all complications as less important than family doctors. Conclusion: This is the first study to quantify physicians’ valuation of factors which may drive treatment decisions for DCM. This is a companion study to our previous research on the importance of factors that may drive physicians’ treatment decisions for DCM. We can compare physicians’ results to those for DCM patients who were waiting for surgery, and those who had undergone surgery. In general, the importance of neurologic function and potential complications was inversely related to knowledge of the DCM disease process and treatment. In spine surgery, previous research has shown that SDM discussions are particularly lacking in the exploration of harms. Our findings suggest a possible explanation: physicians assign a lower importance to complications than patients. Our work demonstrates that patients’ values may differ from those of physicians, and that knowledge and experience of the disease process and treatment shape values. In SDM discussions for DCM treatment, surgeons should explicitly ask patients to state their values, and discuss the possibility of values changing through the experience of surgery.

Yushi Hoshino 1,2 , Yoshifumi Kudo 2 , Ichiro Okano 2 , Syu Sakai 1 , Hajime Nishida 2 , Ryo Yamamura 2 , Yusuke Oshita 2 , Ai Sakai 1,2 , Satoshi Yoshiyama 1,2 , Yoshinori Imaizumi 1 1 Deptartment of Orthopedic Surgery, Asahi University Hospital, Gifu, Japan , 2 Deptartment of Orthopedic Surgery, Showa University Hospital, Tokyo, Japan Purpose: The management of acute postoperative pain is important because it affects patient satisfaction, treatment efficacy, and prolonged postoperative pain. Recent studies have also reported gender differences in pain. However, there are few reports on gender differences in acute postoperative pain. In this study, we investigated whether there are gender differences in acute postoperative pain in lumbar posterior decompression surgery. Subjects and Methods: A total of 79 consecutive lumbar posterior decompression surgeries (longitudinal split spinous process widening) were performed at our hospital from January 2020 to October 2021. Pain was evaluated preoperatively and at 1.3.6 hours and 1.3.7 days postoperatively using the Numerical Rating Scale (NRS) to determine pain intensity and the rate of additional analgesic use. All patients underwent multimodal analgesia for postoperative pain management, which consisted of IV-PCA, acetaminophen, and pentazocine administered intravenously at regular intervals. Results: 45 males and 34 females. Mean age: 64 years for males and 69 years for females. Mean number of decompressed vertebrae: male 1.8 vertebrae, female 1.9 vertebrae. Each NRS was as follows: preoperative: male 7 female 7.3; 1 hour postoperative: male 4.1 female 4.4; 3 hours postoperative: male 3.1 female 3.6; 6 hours postoperative: male 2.5 female 1.9; 1 day postoperative: male 4.6 female 4.1; 3 days postoperative: male 3.5 female 3.1; 1 week postoperative: male 2.1 female 1.9. No significant differences were found at any of the timings. Additional analgesics were used in 7 men (15.5%) and 3 women (5.9%). Males tended to use additional analgesics more often. Discussion: Spinal surgery is often associated with severe postoperative pain and difficulty in managing that pain. Recent studies have recognized that women have a low pain threshold and are more susceptible to pain stimulation. In addition, although it has long been thought that there is a single mechanism that produces pain, it has become clear that pain pathways differ by gender, and the possibility has emerged that they may be diverse beyond biological sex. In our current study, acute postoperative pain expressed comparable pain without differences between the sexes. However, we found that men tended to seek additional analgesic rescue medications more often, suggesting that men may have a weaker tolerance to pain stimuli. However, women also accept and are aware of pain similar to men, suggesting the need for aggressive postoperative pain management regardless of gender, regardless of the expression of pain. Conclusion: No differences in postoperative pain after lumbar posterior decompression surgery were found between the sexes. However, men tended to use additional analgesics more frequently. Alexander Baur 1 , Keith Lustig 1 1 Liberty University College of Osteopathic Medicine, Lynchburg, United States Introduction: Spinal cord stimulators (SCS) have gained widespread popularity as a promising tool for managing chronic neurogenic pain. Despite the growing adoption of SCS as a therapeutic approach, there is a lack of demonstrated efficacy. The clinical utilization of SCS is on the rise, despite potential severe complications and the absence of clear evidence supporting its therapeutic benefits. Materials and Methods: The research encompasses a detailed retrospective analysis of the patient's hospital course, focusing on multiple urgent surgical decompressions, with an emphasis on identifying potential preventive measures against such severe complications. This study presents a case involving a liver transplant recipient who developed an acute spinal epidural hematoma subsequent to spinal cord stimulator (SCS) placement. The patient's extensive medical history, characterized by chronic immunosuppression, is thoroughly examined and documented to provide insights for future clinical management. Additionally, all acute hospital management was evaluated to prevent similar complications in the future. Results: The patient experienced acute bilateral leg weakness, sensory deficits, and urinary dysfunction two days following SCS placement. Despite undergoing multiple debridement procedures, there was no improvement in neurological function, and the patient remained paraplegic. This case highlights the critical significance of careful patient selection and rigorous postoperative monitoring. This uncommon scenario also underscores the importance of prompt intervention upon the development of epidural hematomas. Conclusion: This case highlights the need for cautious consideration of SCS due to its serious and lasting side effects in treating chronic back pain. Surgeons should reevaluate the widespread use of SCS, advocating for reserved usage in controlled trials until therapeutic benefits are firmly established. Despite potential pain relief, the risk of complications, including spinal epidural hematoma, should not be underestimated. Further research is urged to understand therapeutic benefits and assess short- and long-term complications comprehensively. Keywords: Spinal epidural hematoma, Spinal cord stimulator, paraplegia, case report Ayrat Syundyukov 1 , Pavel Kornyakov 1 1 Federal State Budgetary Institution «Federal Center for Traumatology, Orthopedics and Arthroplasty» of the Ministry of Health of the Russian Federation (Cheboksary), Russia, Pediatric Orthopedic, Cheboksary, Russian Federation Introduction: Three-column spinal osteotomy is a complex surgical procedure with risks of complications, but often necessary for the correction of severe deformities. Purpose: To evaluate complications of three-column osteotomies in the correction of spinal deformities. Methods: Retrospective comprehensive assessment of patients (n = 67) who underwent Schwab 3 (n = 40), 4 (n = 10), 5 (n = 17) three-column osteotomies. Mean age 19.3 (95% CI: 16.1-22.41). Follow-up period: 56.5 months (95% CI: 49.92-63.07). Hemivertebral resections in children were excluded from the study. Results: The overall complication rate was 37%. The revision surgery rate after this procedure was 9%. Neurological complications and complications associated with major blood loss occurred. The nature of the neurological complications was temporary. An infectious complication was observed in 1 case. Most often in our practice, mechanical complications were noted associated with the development of PJK and DJK, as well as pseudarthrosis and fracture of the spinal systems. Differences in the percentage of complications depending on the type of osteotomy are not statistically significant. Conclusions: Despite the complexity of the procedure, according to our data, the level of complications is low. Abhinav Sharma 1 , Frederik Heath 1 , Manaav Mehta 2 , Nicole Goldenhersh 1 , Jason Liang 1 , Nischal Acharya 3 , Michael Steinhaus 4 , Hao-Hua Wu 1 , Sohaib Hashmi 1 , Don Park 1 , Yu-po Lee 1 , Zorica Buser 5 , Nitin Bhatia 1 1 University of California, Irvine, Department of Orthopaedic Surgery, Orange, United States , 2 University of Massachusetts Chan Medical School, Worcester, United States , 3 University of California, Irvine, Department of Neurological Surgery, Orange, United States , 4 The Spine Institute, Salt Lake City, United States , 5 NYU Grossman School of Medicine, Department of Orthopedic Surgery, New York, United States Introduction: Obesity portends worse outcomes after elective spine surgery. The effect of body mass index (BMI) classification on postoperative outcomes, pulmonary embolism (PE), and deep vein thrombosis (DVT), following elective cervical spine surgery has yet to be previously evaluated at a large scale. The purpose of this study was to evaluate the effect of obesity class on perioperative complications following elective cervical spine surgery. Material and Methods: Inclusion criteria were adults ≥ 18 years of age who underwent elective cervical spine surgery from 2015 to 2021 included in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. 30-day post-op complication data was evaluated using multivariate models examining the risk of return to OR, readmission, PE, and development of DVT. Obesity was further classified as type 1 (BMI 30-34.9), type 2 (BMI 35-39.9), and type 3 (BMI > 40). Predictors included BMI category, age, sex, smoking, diabetes, uremia, BUN creatinine ratio, malnourished and ASA classification. Results: Of 23,416 patients who met inclusion criteria, 82 patients developed a DVT requiring therapy and 67 developed a PE. There was no statistically significant increased risk of developing DVT postoperatively among BMI classification. There was, however, a significantly elevated risk of developing postoperative PE according to obesity class in both univariate and multivariate analysis, with type 3 obesity corresponding to a univariate odds ratio (OR) of 2.42 (p = 0.04) and multivariate OR of 3.16 (p = 0.009). Type 1 obesity was significantly associated with readmission on univariate (OR 0.81; p = 0.04) and multivariate (OR 0.80; p = 0.03) analyses. Univariate odds ratios for type 1 (OR 0.61; p = 0.005) and type 2 (OR 0.62; p = 0.03) obesity, and multivariate odds ratio for type 1 obesity (OR 0.60; p = 0.005) were significantly decreased for return to OR. Malnourished patients were at elevated risk for DVT (OR 3.25; p < 0.0001), and increased age (OR 1.03; p = 0.006) and smoking elevated risk for PE (OR 2.12; p = 0.006). Conclusion: Increasing BMI results in elevated postoperative complication risk following elective cervical spine surgery, specifically for PE in those with type 3 obesity. However, rates of readmission and return to OR were demonstrated to decrease with BMI and obesity class. Due to the elevated risk of poorer outcomes according to severity of obesity, multidisciplinary counseling and possible deferral of elective surgery until nutritional status is optimized and bariatric evaluation is complete may be warranted. Abhinav Sharma 1 , Paramveer Birring 1 , Manaav Mehta 2 , Nicole Goldenhersh 1 , Nischal Acharya 3 , Frederik Heath 1 , Jason Liang 1 , Maziar Moslehyazdi 1 , Amanda Tedesco 1 , Michael Steinhaus 4 , Hao-Hua Wu 1 , Sohaib Hashmi 1 , Don Park 1 , Yu-po Lee 1 , Zorica Buser 5 , Nitin Bhatia 1 1 University of California, Irvine, Department of Orthopaedic Surgery, Orange, United States , 2 University of Massachusetts Chan Medical School, Worcester, United States , 3 University of California, Irvine, Department of Neurological Surgery, Orange, United States , 4 The Spine Institute, Salt Lake City, United States , 5 NYU Grossman School of Medicine, Department of Orthopedic Surgery, New York, United States Introduction: The choice of decompression with fusion or decompression alone for management of degenerative spondylolisthesis (DS) is controversial. Advantages of fusion include a potentially reduced rate of revision surgery; however, fusion has also been shown to be associated with increased rates of postoperative complications, length, complexity, and cost of surgery. The purpose of this study was to investigate differences in perioperative outcomes of lumbar DS patients treated with decompression and fusion versus decompression alone. Material and Methods: Inclusion criteria were adults ≥ 65 years of age who presented with spondylolisthesis of the lumbar or lumbosacral region (ICD10: M43.16 and M43.17) and had undergone surgical procedures including laminectomy, laminotomy (CPT codes 63047, 63030) with or without fusion (CPT code 22612) included in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. 30-day post-op complication data and American Society of Anesthesiologist (ASA) physical status classification were evaluated through Chi-square and analysis of variance (ANOVA) tests, with results further stratified according to ASA classification using ANOVA with post-hoc Tukey and Chi-square analyses. Complications consisted of estimated 30-day mortality and morbidity, reintubation, unplanned reoperation, unplanned readmission, and length of stay in the hospital (days), superficial infection, deep wound infections, sepsis, bleeding requiring transfusions, deep vein thrombosis, pulmonary embolism, urinary tract infection, renal insufficiency, renal failure, myocardial infection, cardiac arrest, and stroke. Results: 1,299 patients met inclusion criteria. Patients undergoing decompression with fusion had higher mean mortality (estimated probability 0.003 vs. 0.002, p = 0.021), morbidity (estimated probability 0.041 vs. 0.037, p < 0.001), mean length of stay (4.0 ± 5.9 d vs. 2.9 ± 5.3 d, p < 0.001), bleeding risk necessitating transfusion (9.6% vs. 5.9%, p < 0.017), and cardiac arrest (0.0% vs. 0.5%, p = 0.023). Stratification by ASA scores demonstrated an overall higher rate of 30-day postoperative complications associated with increasing ASA score for both cohorts, with a correspondingly greater increase in complications in the decompression and fusion cohort relative to decompression alone patients within each ASA group. Conclusion: In patients undergoing surgery for lumbar DS, decompression with fusion is associated with higher estimated mortality, morbidity, and risk of immediate postoperative complications, including bleeding risk necessitating transfusion, cardiac arrest requiring CPR and longer length of stay relative to decompression alone in the first 30 days after surgery. These findings suggest consideration of decompression alone as an appealing treatment option for lumbar DS, particularly for patients with higher ASA scores and those at higher risk for postoperative complications. Rodrigo Muscogliati 1,2 , Elie Najjar 1 , Ahmed Hassan 1,3 , Weronika Nocun 1 , Nasir Quraishi 1 1 Queen's Medical Centre, Nottingham University Hospitals, Nottingham, United Kingdom , 2 Hull-York Medical School, Hull, United Kingdom , 3 Department of Orthopedics and Trauma Surgery, Assiut University School of Medicine, Assiut, Egypt Background: Incidental durotomies are well known complications in spinal surgeries. Due to paucity of literature, the difference in efficacy of early mobilization after such a complication between minimally invasive (MISS) and open spine surgery (OSS) remains unclear. Objective: To systematically evaluate the relevant literature regarding the outcomes of mobilization within 24 hours after an incidental durotomy in OSS versus MISS lumbar or thoracic surgery with respect to the length of hospital stay, minor complications and reoperation rates. Methods: A systematic review of the English language literature using Pubmed, Embase and Cochrane and dating up until October 2022 was undertaken following Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Quality of evidence was assessed using a modified version of Sackett's Criteria of Evidence Support. Results: Of a total of 102 articles, 11 studies met the inclusion criteria (1 Level I and 9 level III and 1 Level IV evidence) and were analyzed. Overall, 398 patients of mean age 59.9 (23-78) years had an incidental dural tear (IDT) during an OSS and were mobilized within 24 hours. Dural repair was performed in 95% of the cases. The average follow-up period was 8.3 months (3-12 months). The average length of stay (LOS) was 5.7 (2.6-8.3) days. Thirty four out of 398 (8.5%) patients required reoperation while the rate of minor complications was 82 out of 350 (25.4%) (5 studies). Additionally, 161 patients of mean age 61.5 (30-85) years with IDT during an MISS were mobilized after 24 hours; 98% underwent a primary repair. The average follow-up was 7.3 months (2-17 months). The average LOS was 1.25 (0.75-3.3) days. Five patients required reoperation (1.04%) while the rate of minor complications was 12 out of 161 (4.7%). Conclusion: MIS techniques are much more forgiving when it comes to major and minor complications when compared to OSS, while also leading to a shorter length of stay. Chun Wai Hung 1 , Fthimnir Hassan 2 , Nathan Lee 3 , Steven Roth 4 , Justin Scheer 5 , Joseph Lombardi 2 , Zeeshan Sardar 2 , Ronald A. Lehman 2 , Lawrence Lenke 2 1 Houston Methodist, Houston, United States , 2 Columbia University Irving Medical Center, New York, United States , 3 Midwest Orthopaedics at RUSH, Chicago, United States , 4 University of Florida Medical Center, Gainesville, United States , 5 Cedar Sinai Medical Center, Los Angeles, United States Introduction: Within the spinal cord shape classification system (SCSCS), type 3 spinal cords (actual cord deformation on apical axial MRI scan) have been shown to be associated with much higher risk of intraoperative neuromonitoring (IONM) data loss. The current study is to identify whether there are variables among type 3 cord shapes that further predicts the likelihood of IONM changes within this subgroup. Methods: This is a retrospective cohort study of consecutive patients with type 3 spinal cords undergoing spinal deformity surgery from a single academic institution between 2016-2023. The primary outcome examined was whether there was IONM data loss. Demographic, clinical, operative, and radiographic variables were compared in those patients with and without IONM data loss. Results: A total of 79 patients with type 3 spinal cords meeting the inclusion criteria were identified. Of these, 30 pts (38%) had IONM data loss, while 49 pts (62%) did not. In comparing the IONM loss group with the no IOMN change group, there were no differences between the groups in age or BMI. There were no significant differences in the mean preoperative coronal deformity angular ratio (C-DAR), sagittal DAR (S-DAR), or total DAR (T-DAR). In addition, there were no significant differences in the mean change in C-DAR, S-DAR, or T-DAR between the groups when comparing the postoperative versus preoperative measurements. There was no difference in proportion of patients with a vertebral column resection (VCR), or in the mean instrumented number of levels. However, there was a significantly higher estimated blood loss (EBL) (1320 ± 614 vs 1049 ± 468, p = 0.03) in the IONM loss group. Conclusions: In this largest reported cohort patients with type 3 spinal cords undergoing spinal deformity surgery, somewhat surprisingly, the only factor found to be significantly associated with risk of IONM data loss was higher EBL. Thus this is important for deformity surgeons to realize when treating this specific group of high risk patients. Sarthak Mohanty 1 , Stephen Stephan 2 , Christopher Mikhail 3 , Josephine Coury 4 , Fthimnir Hassan 4 , Erik Lewerenz 4 , Nathan Lee 5 , Justin Scheer 3 , Steven Roth 6 , Chun Wai Hung 7 , Joseph Lombardi 4 , Zeeshan Sardar 4 , Ronald A. Lehman 4 , Lawrence Lenke 4 1 Massachusetts General Hospital, Boston, United States , 2 Scripps Health, La Jolla, United States , 3 Cedar Sinai Medical Center, Los Angeles, United States , 4 Columbia University Irving Medical Center, New York, United States , 5 Midwest Orthopaedics at RUSH, Chicago, United States , 6 University of Florida Medical Center, Gainesville, United States , 7 Houston Methodist, Houston, United States Introduction: Nearly 20% of adult spinal deformity (ASD) patients require revision within five years – largely due to either pseudarthrosis or proximal junctional kyphosis (PJK). In clinical counseling, revision patients are often homogenized due to scarcity of data comparing outcomes between them. This study sought to compare patient reported outcomes (PROs) among patients undergoing revision for pseudarthrosis (Pseudo) versus patients undergoing revision for proximal junctional kyphosis (PJK). Methods: This study compared patients undergoing revisions for pseudarthrosis (Pseudo) and proximal junctional kyphosis (PJK) following adult spinal deformity (ASD) surgery at a single center from 2016 to 2021. The primary outcomes were two-year patient-reported outcomes (PROs) and the attainment of the minimum clinically important difference (MCID). Patients were propensity score matched (PSM) based on baseline sagittal alignment measures, including the Maximum Coronal Cobb angle, pelvic incidence, T1 pelvic angle (T1PA), sagittal vertical axis relative to the cranium (CrSVA-Hip), and C7 sagittal vertical axis (C7 SVA). To validate the findings from the PSM cohort, a multivariable model was employed to assess the impact of Pseudo versus PJK on MCID attainment, adjusting for age, sex, and baseline alignment measures. Results: 119 patients with average age 64.43, 65.55% females, 17.8% osteoporotic, and 33.61% receiving 3CO were included. Compared to Pseudo patients (n = 78), PJK (n = 41) cohort was younger (65.83 vs 61.78, p = 0.0527) and had lower PI-LL mismatch (31.12 vs 21.68, p = 0.011) and CrSVA-H (72.67 cm vs 43.37 cm, p = 0.0367). After 1:1 PSM, the Pseudo and PJK groups (n = 37 each) had comparable age (p = 0.1514), gender (72.97% female, p > 0.9999), ASA (p = 0.7499), Coronal Cobb (21.31 vs 21.75, p = 0.7962), CrSVA-H (57.88 cm vs 44.77 cm, p = 0.591), PI-LL (p = 0.1529), and T1PA (p = 0.2899). At baseline, the PSM cohort showed no preop differences in SRS Activity, Pain, Appearance, Satisfaction, Total, or ODI (p > 0.05), except for SRS Mental Health, which was significantly better in the Pseudo cohort (3.64 vs 3.3, p = 0.0154). At 2Y follow-up, Pseudo patients had superior SRS Pain (3.57 vs 3.08, p = 0.015), Mental Health (4.02 vs 3.55, p = 0.0021), and Total scores (3.68 vs 3.31, p = 0.0133). Pseudo patients had greater improvement in SRS pain (1.41 vs 0.94, p = 0.0095) and SRS-Total (1.01 vs 0.74, p = 0.0119). A higher proportion of Pseudo patients attained MCID in SRS Pain (93.94% vs 69.7%, OR: 3.145, p = 0.0363) and Appearance (93.94% vs 66.67%, OR: 3.523, p = 0.0203). In a multivariable model with all included patients, Pseudo independently had higher odds of achieving MCID (vs PJK) in SRS Pain (OR:2.380; p = 0.017), Appearance (OR:2.474; p = 0.013), and ODI (OR:2.725; p = 0.047). Conclusions: Revision patients for pseudarthrosis have superior two-year patient reported outcomes versus PJK patients. Fthimnir Hassan 1 , Zeeshan Sardar 1 , Lawrence Lenke 1 , Sarthak Mohanty 2 , Peter Passias 3 , Eric Klineberg 4 , Virginie Lafage 5 , Shay Bess 6 , Justin Smith 7 , D. Kojo Hamilton 8 , Jeffrey Gum 9 , Renaud Lafage 5 , Jeffrey Mullin 10 , Michael Kelly 11 , Bassel Diebo 12 , Thomas Buell 8 , Justin Scheer 13 , Breton Line 6 , Han Jo Kim 14 , Khaled Kebaish 15 , Robert Eastlack 16 , Alan Daniels 12 , Alex Soroceanu 17 , Gregory Mundis 16 , Richard Hostin 18 , Themistocles Protopsaltis 3 , Munish Gupta 19 , Frank Schwab 5 , Christopher Shaffrey 20 , Christopher Ames 21 1 Columbia University Irving Medical Center, New York, United States, 2 Massachusetts General Hospital, Boston, United States, 3 New York University, Langone Medical Center, New York, United States, 4 UTHealth McGovern Medical School, Houston, United States, 5 Lenox Hill Hospital, New York, United States, 6 Denver International Spine Center, Denver, United States, 7 University of Virginia Health System, Charlottesville, United States, 8 University of Pittsburgh Medical Center, Pittsburgh, United States, 9 Norton Leatherman, Louisville, United States, 10 University of Buffalo, Buffalo, United States, 11 Rady's Childrens Hospital, San Diego, United States, 12 Warren Alpert School of Medicine, Brown University, Providence, United States, 13 Cedar Sinai Medical Center, Los Angeles, United States, 14 Hospital for Special Surgery, New York, United States, 15 Johns Hopkins University School of Medicine, Baltimore, United States, 16 Scripps Health, La Jolla, United States, 17 University of Calgary, Calgary, Canada, 18 Southwest Scoliosis Institute, Plano, United States, 19 Washington University in St Louis, St Louis, United States, 20 Duke University Medical Center, Durham, United States, 21 University of San Francisco, San Francisco, United States Introduction: Reports have shown that cell saver salvage (CS) processing introduces fragile RBCs with sub-lethal injuries to its recipients. In a propensity-score matched analysis, Mohanty et al discerned that a CS to estimated blood loss (EBL) ratio (CS:EBL) ≥ 0.33 is shown to be associated with higher rates of 30D readmissions. We aim to analyze the effect of this ratio on cardiopulmonary (CP) and renal complications. Methods: This study is an analysis of a prospective, multicenter cohort of ASD patients with ≥ 1 procedural and/or radiographic criteria: PI-LL ≥ 25°, TPA ≥ 30°, SVA ≥ 15 cm, thoracic scoliosis ≥ 70°, thoracolumbar scoliosis ≥ 50°, global coronal malalignment ≥ 7 cm, ≥ 12 instrumented levels, and/or undergoing 3-column osteotomy (3CO). Patients were dichotomized based on whether they received a CS:EBL ratio ≥ 0.33 or < 0.33. Patients were excluded if they had no CS transfused. Key outcomes included renal and CP-related medical complications. Patient characteristics, preoperative labs, operative data, and radiographic parameters were compared through bivariate analyses to assess for key differences in patient and treatment characteristics. A conceptual multivariable logistic regression model was built to assess risk factors associated with the primary outcome. Results: 406 patients were included in this analysis with 10.6% (N = 43) and 89.4% (N = 363) patients having CS:EBL ≥ 0.33 and < 0.33, respectively. The CS:EBL ≥ 0.33 patients were older (66.2 ± 12.2yrs vs 58.9 ± 16.4, p = 0.0007), experienced less EBL intraoperatively (1048.3 ± 852.2cc vs 1695.6 ± 1295.3cc, p < 0.0001), less instrumented levels (TIL) (12.2 ± 3.3 vs 14.1 ± 3.6, p = 0.0001), less posterior column osteotomies (PCOs) performed (72.1% vs 86.8%, p = 0.0103) and less major coronal cobb correction (-17.0 ± 14.6 vs -22.7 ± 16.7, p = 0.0373). Despite comparable transfusion rates, CS:EBL ≥ 0.33 patients has lesser packed red blood cells (pRBC), fresh frozen plasma (FFP), and platelet units transfused intraoperatively (p < 0.05). No significant differences were observed among overall CP and renal complications. However, when stratifying CP complications by type, CS:EBL ≥ 0.33 patients experienced a greater rate of pulmonary embolisms (PE) (9.3% vs 1.4%, p = 0.0093) within 30D of surgery. A multivariable logistic regression model adjusting for age, EBL, PCOs performed, TIL, change in the max coronal cobb angle, and colloids, pRBC, FFP, and platelet units transfused discerned CS:EBL ≥ 0.33 to be an independent risk factor for the development of PE, conferring an OR of 6.57 (1.75-24.66) with excellent model diagnostics (Model p-value = 0.0031, AUC = 0.92, Hosmer and Lemeshow Goodness-of-Fit Test p-value = 0.7264). Conclusions: Patients with a CS:EBL ratio ≥ 0.33 have a 6.57x greater risk of developing a pulmonary embolisms early postop independent of EBL and transfusions administered. The findings support the re-evaluation of CS use in this patient population based on perceived benefits. Henry Avetisian 1 , Nicole Hang 1 , Zabiullah Bajouri 2 , Zoe Fresquez 1 , Zorica Buser 3 , John Liu 4 , Jeffrey C. Wang 1 1 Keck School of Medicine of USC, Department of Orthopaedic Surgery, Los Angeles, United States , 2 Dartmouth Health, Department of Neurological Surgery, Lebanon, United States , 3 NYU Grossman School of Medicine, New York, United States , 4 USC Keck School of Medicine, Department of Neurological Surgery, Los Angeles, United States Introduction: Parkinson’s Disease (PD) is a chronic, progressive neurodegenerative disease characterized by tremor, rigidity, bradykinesia, and postural instability, all of which severely interfere with daily activities. Of particular interest concerning the clinical symptoms of PD is its negative impact on bone quality. As such, patients with Parkinson’s Disease are at a higher risk of both degenerative and deformative spine pathology, which then necessitates a higher rate of spine surgery in comparison to otherwise healthy individuals. Due to the increasing rise of spinal fusion rates in patients with Parkinson’s Disease, it is crucial to identify the rates of postoperative complications. Of particular interest is the thoracic region of the spine, which is notorious for being difficult to access due to the various sensitive anatomical structures located in the region. Although the complication rates of cervical, cervicothoracic, thoracolumbar, and lumbar spine fusion in patients with Parkinson’s Disease have been extensively reviewed, the complication rates associated with thoracic spine fusion in this patient population have yet to be assessed. Methods: Using ICD-10 codes, the PearlDiver database was queried from quarter 3 of 2015 to 2020 to identify the experimental group; individuals who were concomitantly afflicted with Parkinson’s disease and thoracic spine pathology, and the control group; non-Parkinson’s disease patients who were afflicted with thoracic spine pathology. From there, CPT codes were used to identify the number of patients who underwent thoracic spine fusion in each patient population. Finally, ICD-10 codes were used to assess the complication rates 90 days after the index procedure for both the PD and non-PD groups. Results: In total, the PearlDiver database identified 2833 patients who were concomitantly diagnosed with a thoracic spine pathology and PD. Of that patient population, 236 patients (8.33%) underwent thoracic spine fusion from quarter 3 of 2015 to 2020. 9081 control (Patients without a PD diagnosis who underwent thoracic spine fusion due to a thoracic spine pathology) patients were identified. Patients with Parkinson’s disease who underwent thoracic spine fusion are more likely to experience gastrointestinal (28.39%), neurological (25%), respiratory (19.92%), dermatological (11.86%), psychiatric (15.25%), and cardiovascular complications (22.46%) 90 days after the index procedure when compared to the control group. Conclusion: Patients with PD who undergo spinal fusion for thoracic spine pathology experience significantly higher complication rates. At times, the odds of experiencing post-operative complications were as high as 3 (GI complications) compared to patients who receive T-spine surgery and do not have Parkinson’s Disease. When offering thoracic spine surgical procedures for patients with PD, it is important to consider the increased morbidity that these patients face. Samir Dalvie 1 , Sourav Chatterjee 2 , Kshitij Chaudhari 2 1 PD Hinduja National Hospital, Spine Surgery, Mumbai, India , 2 PD Hinduja National Hospital, Mumbai, India Background: Age and general health status are major points of concern in the decision-making process when it comes to cervical spine surgeries in the elderly. While there have been studies on the various frailty indices in their ability to predict outcomes in spine surgery, there have been few articles that have investigated the utility of the 5-point modified Frailty Index (mFI-5) for this purpose. Our study attempts to have a granular view of the problem of frailty in the elderly and study the correlation between the mFI-5 and American society of anesthesiologists (ASA) classes, and the 90-day surgical outcome of patients of 60 years and above, operated for degenerative cervical spine pathologies. Materials and Methods: This is a single-center retrospective study of prospectively collected data on 41 patients aged 60 years and above who were operated at our institute between January 1, 2017, and December 31, 2022. We studied the correlation of mFI-5, ASA class and the Spinal Surgical Invasiveness Index (SII) with various outcome variables like length of hospital stay, need for ICU stay, complications, severe adverse events (Clavien Dindo grade 4 and above), re-intubation, unplanned re-admission, and need for re-operation. Results: Statistical analysis showed a significant correlation between ASA class and mFI-5 scores (Chi square test, p-value: 0.0401) and between ASA scores and the need for an ICU stay (Chi square test, p-value: 0.0047). SII was found to correlate with length of hospital stay (Spearman rank test, p-value: 0.0037) and with need for ICU care (Mann-Whitney U test, p-value 0.0422). However, there was no significant correlation between the mFI-5 scores and the outcome variables. Conclusion: Although there was no significant correlation between mFI-5 and the 90-day surgical outcome, variables like ASA and SII had a bearing on it. Thus, it can be stated that the outcome of cervical spine surgery in the elderly is multifactorial. While frailty should put the healthcare team on alert while dealing with such patients, it should not discourage them from offering a surgical solution when required, as efficient peri-operative management by the surgical, anesthesia, and critical care teams can lead to favorable 90-day outcomes. Klaus Schnake 1,2 , Denis Rappert 1 , Olga Cheremina 1 , Alexander Hammer 1,3 1 Malteser Waldkrankenhaus St. Marien, Center for Spinal and Scoliosis Surgery, Erlangen , 2 Paracelsus Medical University, Department of Orthopedics and Traumatology, Nuremberg, Germany , 3 Paracelsus Medical University, Department of Neurosurgery, Nuremberg, Germany Introduction: Obesity is an increasing problem regarding healthcare in terms of coherent morbidities but also in terms of increasing revision rates in surgery. A collective of posterior thoracolumbar spinal fusion surgery up to 4 segments was examined regarding the impact of obesity on early revision surgery (≤ 3 months). Material and Methods: In this monocentric, prospective study over a period of 24 months, 227 patients were included. Besides obesity (Body mass index ≥ 30) the impact on early revision surgery (up to 3 months) of dural tear, previous local surgery, age, sex, ASA-grade (American Society of Anesthesiologists), diabetes mellitus, preoperative anticoagulation, number of segments, intraoperative blood loss, and length of surgery were examined in terms of univariate (Chi square test, t-test, Mann-Whitney-U-Test) and multivariate (logistic regression analysis) testing. Results: BMI ≥ 30 (10.9% / BMI < 30 vs 25.3% BMI ≥ 30; p = 0.005) was a significant factor in univariate testing leading to increased early revision rates besides ASA-grade (12.4% ASA grade 1 and 2 vs 24.4% ASA grade ≥ 3; p = 0.019) and increased intraoperative blood loss (474.1 ml ± 275.3 ml vs 587.2 ml ± 310.5 ml; p = 0.026). In multivariate testing every additional BMI point came along with increased early revision rates (OR 1.09; 95% CI 1.02-1.16; p = 0.012). Early revision rates of the obesity subcategories ranged from 5.7% in patients with normal weight to 31.0% in extremely obese (BMI ≥ 35 kg/m2) patients (OR 0.13; 95% CI 0.035-0.51; p = 0.0017). Conclusion: For the prediction of early revision surgery in posterior thoracolumbar spinal fusion surgery up to 4 segments obesity is an important factor. Yushi Hoshino 1 , Syu Sakai 1 , Hajime Nishida 2 , Ichiro Okano 2 , Yusuke Oshita 2 , Ai Sakai 1 , Satoshi Yoshiyama 1 , Chikara Hayakawa 2 , koutaro tsuchiya 2 , Yoshinori Imaizumi 1 , Yoshifumi Kudo 2 1 Asahi Univ. Hospital, Gifu, Japan , 2 Showa Univ. Hospital, Tokyo, Japan Purpose: The management of acute postoperative pain is important because it affects patient satisfaction, treatment efficacy, and prolonged postoperative pain. There are various types of lumbar spine surgery, and it has been reported that the intensity of postoperative pain varies depending on the surgical technique. In recent years, however, postoperative pain has been improved by aggressive pain management. In particular, postoperative multimodal analgesia has improved postoperative pain. In this study, we investigated whether postoperative posterior lumbar decompression and posterior lumbar intervertebral fusion can be performed with the same level of postoperative pain intensity by using active postoperative multimodal analgesia. Subjects and Methods: From January 2020 to September 2022, 45 patients underwent lumbar posterior decompression surgery (Group D) and 26 patients underwent lumbar posterior intervertebral fusion surgery (Group P), each with one vertebra, consecutively at our hospital. Pain was evaluated preoperatively, 1.3.6 hours postoperatively, and 1.2.3.7 days postoperatively using the Numerical Rating Scale (NRS). For postoperative pain management, all patients underwent IV-PCA and multimodal analgesia with IV acetaminophen and pentazocine on the day of surgery. On the day after surgery, all patients received IV-PCA, regular IV acetaminophen, and oral NSAIDs. On the second postoperative day and thereafter, only NSAIDs were administered. Results: Gender: Group D: 26 males and 19 females; Group P: 15 males and 11 females; mean age: Group D: 56 years; Group P: 66 years; operative time: Group D 76.2 minutes; Group P 138.2 minutes. Mean intraoperative blood loss: Group D 43.2 ml, Group P 170.9 ml. Each NRS was as follows: preoperative: Group D 7.2, Group P 7.6; 1h postoperative: Group D 5.8, Group P 6.1; 3h postoperative: Group D 3.9, Group P 4.8; 6h postoperative: Group D 3.8, Group P 3.3; 1d postoperative: Group D 2.9, Group P 5.2; 2d postoperative 2d: Group D 4.1, Group P 4.4, 3d: Group D 3.6, Group P 4.4, 1w: Group D 2, Group P 2.8. At 1d postoperatively, Group P was significantly more painful. Discussion: Spinal surgery often causes severe postoperative pain that is difficult to control. In recent years, Multimodal analgesia for acute postoperative pain has been shown to improve pain management in the early postoperative period. In the present study, it was expected that postoperative pain would be more intense with PLIF, but due to the effect of multimodal analgesia, the pain intensity on the day of surgery improved to almost the same level as that of lumbar posterior decompression surgery. However, on the day after surgery, when physical activity became possible, the intensity of pain temporarily increased with PLIF, suggesting that active involvement at the start of physical activity is necessary for pain management in PLIF. Conclusion: In terms of the effect of multimodal analgesia on acute postoperative pain, lumbar posterior decompression and lumbar posterior intervertebral fusion had the same level of pain on the day of surgery, but the intensity of pain on the day after surgery was higher with lumbar posterior intervertebral fusion. Olga Sergeenko 1 , Alexandr Burtcev 1 , Dmitriy Savin 1 1 Ilizarov Center, Spinal Department, Kurgan, Russian Federation Objectives: This study aims to report and analyze two cases of tension hemothorax in patients with neurofibromatosis type 1 (NF1) undergoing scoliosis surgery, highlighting the incidence, etiology, and optimal treatment strategies. Methods: We present two detailed cases of tension hemothorax in NF1 patients who underwent scoliosis surgery. Clinical presentations, diagnostic findings, treatment interventions, and outcomes were meticulously documented. A literature review was conducted to contextualize these cases within the broader spectrum of tension hemothorax in NF1 patients undergoing similar surgeries. Results: Both cases involved severe complications requiring immediate surgical interventions. The first patient experienced arterial bleeding necessitating endovascular embolization, while the second patient required open thoracotomy. Postoperative management included intensive monitoring and multidisciplinary care. The literature review supported these findings, indicating that surgical interventions such as chest tube insertion, thoracoscopy, and angiography with endovascular embolization are common in such cases. Conclusion: These cases underscore the critical need for vigilance and prompt intervention in managing tension hemothorax in NF1 patients undergoing scoliosis surgery. A multidisciplinary approach is essential for optimizing treatment outcomes and improving understanding of this rare but life-threatening complication in this specific surgical context. Keywords: neurofibromatosis type 1; neurofibromatosis-induced vasculopathy; tense hemothorax; dystrophic scoliosis. Gonzalo Kido 1 , Nicolas Molho 1 , Patricio Encinar 1 , Matias Petracchi 1 , Carlos Sola 1 , Marcelo Gruenberg 1 1 Hospital Italiano de Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina Introduction: Postoperative complications significantly contribute to morbidity, mortality, prolonged hospital stays, and increased healthcare costs. Identifying ideal candidates for surgical treatment and predicting postoperative outcomes is crucial. The American College of Surgeons developed a frailty index that was initially comprised of 11 items but was later modified to 5 items. Both versions have been validated across various surgical specialties and specifically for spinal surgery. However, there are limited studies assessing the 5-item modified frailty index (IFm) as a predictor of morbidity and mortality in low-complexity spinal surgeries. This study aims to evaluate the discrimination and calibration of the IFm for predicting major complications (Dindo-Clavien classification grade 3 or higher) at 90 days in patients undergoing thoracolumbosacral spine surgery and to compare its predictive performance in low-complexity versus medium-high complexity surgeries. Materials and Methods: We conducted a retrospective cohort analysis of patients aged over 18 who underwent thoracolumbosacral spine surgery at the Italian Hospital of Buenos Aires from January 2017 to December 2020. The 5-item IFm was utilized to assess frailty. Postoperative complications were classified from grades 1 to 5 according to the Dindo-Clavien classification within the first 90 days. We recorded days until a major complication occurred, any unscheduled readmissions or reoperations within 90 days, and whether there were deaths during the 180-day follow-up. Demographic data (age, sex, BMI) and surgery-related variables (type of pathology, surgical procedure, complexity: low, moderate, high) were collected. Results: A total of 839 patients participated, with a mean age of 62.8 years (SD 16.8). Among these, 69 patients (8.22%) experienced at least one major complication (Dindo-Clavien grade 3 or higher). The cohort included 478 patients (57%) who underwent low-complexity surgery, 236 (28.1%) moderate-complexity, and 125 (14.9%) high-complexity procedures. Compared to patients with an IFm of 0, those with an IFm of 2 had 3.8 times greater odds (OR: 3.8, SD 1.3; p < 0.01) and those with an IFm of 3 had 7.7 times greater odds (OR: 7.7, SD 3.8; p < 0.01) of experiencing a major complication. The model had an area under the ROC curve (AUC) of 0.66 (95% CI 0.60-0.70), with the optimal cut-off at IFm ≥ 2, yielding a sensitivity of 50% and specificity of 79%. Calibration assessments indicated excellent performance (slope of 1, CITL of 0). The Hosmer-Lemeshow test p-value was 0.99. When analyzing complication rates by surgical complexity, low-complexity surgeries had a 5% major complication rate, moderate complexity 10%, and high complexity 18% (p < 0.01). Discrimination between low complexity and moderate-high complexity groups was slightly lower for low complexity (AUC: 0.63, 95% CI 0.50-0.74) than moderate-high complexity (AUC: 0.67, 95% CI 0.60-0.75), with no significant difference (p: 0.5). Conclusion: This study confirms that the IFm predicts major postoperative complications in thoracolumbar spine surgery and can discriminate frail patients at risk of complications during low-complexity surgeries. Asrul Syamin Hisyam Yong 1 , Siti Munira Binti Seri Masran 2 1 Hospital Sungai Buloh, Orthopaedics & Traumatology, Sungai Buloh, Malaysia , 2 Hospital Sultan Abdul Aziz Shah, University Putra Malaysia, Orthopaedics & Traumatology, Serdang, Malaysia Introduction: Iatrogenic vascular injury following pedicle screw insertion is rare but can lead to significant morbidity. This complication has been reported in less than 0.1% of cases. Despite these low rates, numerous instances of early or late aortic injuries due to pedicle screws have been documented. Most cases have been managed by hardware removal with assistance from vascular or thoracic surgeons, using various techniques. Here we present the case of a patient with a T6 malpositioned pedicle screw abutting the aorta, which was removed using Video Assisted Thoracoscopy (VAT). Material and Methods: A 25-year-old patient presented to our center with a complaint of T6 radiculopathy pain on the left side of her trunk. She had previously undergone Posterior Spinal Instrumentation and Fusion (PSIF) from T6 to L3 for Adolescent Idiopathic Scoliosis 1 year earlier at another center. Physical examination was unremarkable, except for reduced sensation in the left T6 dermatome. A CT scan revealed a malpositioned left T6 pedicle screw, with its tip near the esophagus and the screw shaft abutting the thoracic aorta. No hematoma or thickening of the thoracic aortic wall was observed in that region. After a thorough discussion with the patient, as well as the vascular and thoracic teams, we planned for removal of the left T6 pedicle screw with the assistance of Thoracic Endoscopic Aortic Repair (TEVAR) and Video-Assisted Thoracoscopy (VAT). The patient was induced and a double lumen endotracheal tube was inserted by the anaesthesia team. This is to facilitate single lung ventilation if open thoracotomy is needed. The patient was placed in a semi-prone position, and the incision was made following the previous PSIF scar. The left rod was cut in situ. Prior to unscrewing the left T6 pedicle screw, the thoracic team performed thoracoscopy for direct visualization during screw removal. The procedure was completed without complications and a prophylactic chest tube was inserted. Results: Postoperatively, the patient was stable, peripheral vascular status remains intact and the chest tube was subsequently removed. Nevertheless, the radiculopathy still remains the same. At 1 year post-operatively, there was an improvement of the radiculopathy pain, however the sensation at T6 dermatome remains reduced. Conclusion: Thoracic pedicle screw malposition is one of the most commonly reported complications in Scoliosis surgery with the rate of between 11% and 15.7%. Despite these high rates, pedicle screw malposition causing vascular injury is rare. When such injuries do occur, optimal management requires close collaboration between vascular surgeons, thoracic surgeons and the anaesthesia team to ensure the best possible outcome. In this case report we shown that VAT is useful because we have direct visualization of the aorta during screw removal. Additionally, TEVAR was already on standby if needed. Rachel Huang 1 , Jonathan Dalton 1 , Otitochukwu Ezeonu 1 , Jeremy Heard 2 , Rajkishen Narayanan 1 , Fatimah Alhassan 1 , Gabrielle Kozlowski 1 , Chloe Herczeg 1 , Jarod Olson 1 , Jose Canseco 1 , Alan Hilibrand 1 , Alex Vaccaro 1 , Chris Kepler 1 , Gregory Schroeder 1 1 Rothman Orthopaedic Institute, Philadelphia, United States , 2 Brown University, Orthopaedic Surgery, Providence, United States Introduction: Spine fusion is one of the most performed orthopedic surgeries in the United States. Metformin, a first-line treatment for type 2 diabetes mellitus (T2DM), is well tolerated and works by activating AMP-activated protein kinase to reduce hepatic glucose production and enhance insulin sensitivity. Several animal studies have demonstrated that metformin can attenuate neuropathic pain via decreased activation of microglia and suppression of inflammatory signaling. To date, no clinical studies have evaluated the impact of metformin on postoperative outcomes following spine surgery. The present study aims to examine the effects of metformin on postoperative pain, surgical outcomes, and patient reported outcome measures (PROMs). Material and Methods: A Structured Query Language (SQL) search was used to identify all patients (> 18 years old) who underwent a 1-2-level posterior lumbar decompression and fusion (PLDF) surgery between 2018-2020. The SQL search, combined with manual chart reviews, was used to gather patient demographics and confirm diabetes diagnoses. Charts were also checked for metformin use and dosage. Surgical outcome data including length of stay (LOS), inpatient complications, hospital readmission, emergency department visits, and reoperations were also recorded. Opioid consumption data, including total prescriptions and morphine milligram equivalents (MME), for one year before to one year after surgery, was obtained from the Pennsylvania Prescription Drug Monitoring Program (PDMP). In-hospital MME and preoperative and postoperative PROMs were obtained through SQL search including the mental (MCS) and physical (PCS) component scores of short-form 12, Oswestry Disability Index (ODI), visual analogue scale (VAS) back pain, and VAS leg pain. Statistical analysis was performed and a p-value < 0.05 was statistically significant. Linear and Poisson regressions were also conducted. Results: Of the 149 patients with T2DM who underwent a 1-2 level PLDF surgery, 109 (73.2%) were taking metformin. The metformin group had fewer total preoperative opioid prescriptions (2.27 ± 3.26 vs. 4.4 ± 4.93; p = 0.020), higher MMEs from 30-60 days preoperatively (26.7 ± 45.2 vs. 7.6 ± 19.5; p = 0.008), but no difference in MMEs in the 30 days prior to surgery or the 30 days after surgery compared to the no metformin group. Patients on metformin had a lower Elixhauser (2.12 ± 1.32 vs. 2.98 ± 1.49; p = 0.001) but were otherwise similar in demographic and surgical characteristics than patients not on metformin. Patients on metformin had lower postoperative MMEs at 30-90 days (32 ± 55.9 vs. 57.9 ± 68.4; p = 0.008) and 90-365 days (66 ± 180 vs. 139 ± 269; p = 0.013). Linear regression analyses identified metformin use as independently predictive of fewer postoperative MMEs (Estimate -21.58, CI -42.43 to -0.72; p = 0.045). Metformin patients had shorter hospital LOS (3.93 ± 3.02 vs. 4.52 ± 1.57; p = 0.002) and more improvement from pre- to postoperative VAS leg pain scores (-2.60 ± 3.80 vs. -5.67 ± 2.41; p = 0.010). All other PROMs were similar between groups. Conclusion: Our study demonstrates that metformin may reduce postoperative opioid consumption in T2DM patients undergoing spine surgery. This study suggests a strategy for better postoperative pain management, potentially reducing opioid dependence and tolerance, and improving overall patient outcomes. Karel Willems 1 , Alexander Debois 1 1 AZ Delta Roeselare, Orthopaedic Surgery, Roeselare, Belgium Introduction: Endoscopic decompression surgery is increasingly favored for its minimally invasive approach and faster recovery times in lumbar spine conditions. However, the limited visual field necessitates precise anatomical knowledge and careful identification of surgical landmarks. This article presents anatomical variations, including a previously undocumented variation high split of the sacral nerve roots at L5-S1, that poses significant challenges during surgery. Objective: To highlight the importance of advanced imaging and intraoperative vigilance in identifying and managing anatomical anomalies, particularly during endoscopic lumbar spine surgery. Discussion: The anatomical anomaly in this case, characterized by a high split of bilateral S2 nerve roots, does not fit into existing classifications of spinal cord malformations or conjoined nerve roots. Unlike typical split cord malformations, this anomaly lacked signs of spinal dysraphism. The rarity and unique presentation of this high split make it important for surgeons, particularly during endoscopic lumbar spine surgeries, to recognize and account for such variations to avoid complications. During the interlaminar endoscopic lumbar discectomy (IELD), precise identification of the dural sac and nerve roots is critical, as misidentification could lead to compromised spinal cord integrity. Retrospective MRI analysis underscored the importance of thorough preoperative imaging and high intraoperative vigilance to detect these anomalies and prevent serious surgical complications. Conclusion: Surgeons must be aware of uncommon anatomical variations like high splits of sacral nerve roots to prevent intraoperative complications. Advanced imaging and vigilant surgical approach are crucial in ensuring safe and effective outcomes in minimally invasive spinal procedures. Rachel Huang 1 , Jonathan Dalton 1 , Michael Carter 1 , Rajkishen Narayanan 1 , Andrew Kim 1 , Hamd Mahmood 1 , Robert Oris 1 , Joydeep Baidya 1 , Jose Canseco 1 , Alan Hilibrand 1 , Alex Vaccaro 1 , Gregory Schroeder 1 , Chris Kepler 1 1 Rothman Orthopaedic Institute, Philadelphia, United States Introduction: As the aging population with cervical spine disease grows, so will the need for posterior cervical decompression and fusion (PCDF). PCDF has a 15-25% complication rate, with wound healing issues being the primary concern due to poor blood flow. Intravenous (IV) dexamethasone, which is a high-potency, long-acting glucocorticoid, has both analgesic and anti-inflammatory effects. However, there have been mixed reports regarding the safety of their use during posterior cervical fusion, mainly due to wound healing concerns. Diabetes is a major cause of morbidity and mortality in the aging population. Dexamethasone can cause hyperglycemia in diabetic patients, which can further compound dexamethasone’s inherent impairment of wound healing. To date, no clinical studies have evaluated the impact of intraoperative IV dexamethasone administration on wound healing in diabetic patients undergoing PCDF. This study aims to evaluate the impact of IV dexamethasone on wound healing and opioid consumption in diabetic patients following PCDF. Material and Methods: All adult patients who underwent a PCDF between 2018-2022 with a diagnosis of type 2 diabetes mellitus (T2DM) were identified via Structured Query Language (SQL) search. Patient demographics and surgical characteristics were collected and recorded. Patient charts were manually reviewed to verify diabetes diagnoses and determine whether intraoperative IV dexamethasone was administered. Preoperative hemoglobin A1c levels and all in-hospital blood glucose readings were recorded. Glycemic variability, defined as the coefficient of variation of all in-hospital glucose levels, was calculated. Surgical outcome data including wound complications and delayed wound healing were also documented. Delayed wound healing was defined as suture removal greater than 21 days after surgery. One year preoperative and postoperative opioid use, and utilization of gabapentinoids, muscle relaxants, and benzodiazepines were all obtained from the Pennsylvania Prescription Drug Monitoring Program. In-hospital morphine milligram equivalents (MME) were obtained from an SQL search. Statistical analysis was performed and a p-value < 0.05 was considered statistically significant. Linear regression was conducted for glycemic variability as the dependent variable. Results: Amongst the 105 patients (38.1% female) with T2DM who underwent a PCDF between 2018-2022, 49 (46.7%) received IV dexamethasone intraoperatively. Those who received IV dexamethasone were younger (61.4 ± 9.35 vs. 65.4 ± 10.5 years; p = 0.042) and had greater postoperative glycemic variability during their hospital stay (30.1 ± 22.1 vs. 23.3 ± 13.2; p = 0.019) than those who did not receive IV dexamethasone. No other differences in demographics, surgical characteristics, readmission rates, wound infections, or delayed wound healing were found between groups. There was no difference in preoperative, in-hospital, and postoperative opioid use and MMEs. Other forms of pain medications were also similarly utilized between groups. Linear regression analyses did not identify dexamethasone use to be a predictor of glycemic variability. Conclusion: This study suggests the safety of perioperative dexamethasone use for posterior cervical fusion in terms of wound healing issues. However, the present work does not appear to suggest a decrease in pain medication requirements after dexamethasone. This indicates that dexamethasone should be utilized when clinically appropriate, but further research is needed to support its inclusion in standardized postoperative protocols. Jonathan Dalton 1 , Rachel Huang 1 , Michael Carter 1 , Gregory Toci 1 , Rajkishen Narayanan 1 , Hamd Mahmood 1 , Ryan Cha 1 , Michelle Davis 1 , Xavier Becsey 1 , Matthew Culkin 1 , Jose Canseco 1 , Alan Hilibrand 1 , Alex Vaccaro 1 , Chris Kepler 1 , Gregory Schroeder 1 1 Rothman Orthopaedic Institute, Philadelphia, United States Introduction: Degenerative cervical myelopathy (CM) is the most common etiology of spinal cord disease amongst elderly patients and is often treated with posterior cervical decompression and fusion (PCDF). The impact of age on surgical outcomes remains controversial. While numerous studies have examined patient reported outcome measures (PROMs) between the young and the old, our goal is to specifically compare preoperative and postoperative PROMs in the elderly population, stratified by decade. Material and Methods: Adult patients who underwent a PCDF between 2017-2022 were identified and their preoperative and postoperative (3 months, 6 months, and 1 year) PROMs were collected via Structured Query Language (SQL) search. Patient PROMs include neck disability index (NDI), visual analog score (VAS) neck and arm, modified Japanese orthopedic association (MJOA), and Short-Form 12 (SF-12) composed of the mental (MCS) and physical (PCS) component score. Patient demographics and surgical characteristics including age, sex, body mass index (BMI), Charlson Comorbidity Index (CCI), smoking status, primary diagnosis, and levels fused were collected through manual chart review and an SQL search. Patients were subsequently divided into decades based on age (50-59, 60-69, 70-79 years). Results: The present study identified 65 (33.5%) patients aged 50-59 years, 87 (44.8%) patients aged 60-69, and 42 (21.6%) aged 70-79. Both CCI (2.40 ± 0.83 (50-59) vs. 3.62 ± 1.06 (60-69) vs. 30.5 ± 6.01 (70-79); p < 0.001) and the average levels fused (3.37 ± 1.81 (50-59) vs. 4.25 ± 1.91 vs. 4.64 ± 2.05 (70-79); p = 0.005) increased with each increase in decade. Preoperatively, those in the 70-79 age group had better performance on NDI (20.4 ± 11.1 (50-59) vs. 17.1 ± 9.91 vs. 13.7 ± 8.06 (70-79); p = 0.022) and VAS neck (5.46 ± 3.19 (50-59) vs. 4.74 ± 2.92 vs. 3.77 ± 2.60; p = 0.028) and worse performance on MCS (45.1 ± 11.0 (50-59) vs. 47.7 ± 11.7 vs. 51.1 ± 11.3 (70-79); p = 0.046) compared to those in 60-69 and 50-59 groups. No significant differences were seen in preoperative and postoperative MJOA, VAS arm, and PCS scores, or in the changes from preoperative to postoperative scores for any PROMs at any time point (3 months, 6 months, 1 year). Conclusion: The current study demonstrates that patients across differing age decades (50-59 vs. 60-69 vs. 70-79 years) achieve similar magnitude of improvement in PROMs following PCDF. This suggests that older patients, despite having more comorbidities and requiring more extensive surgery, can benefit similarly from PCDF compared to younger patients. Sanjit Shah 1,2 , Rebecca Garner 1,2 , Daryn Cass 3 , Dylan Dupont 2 , Christiana Cornea 1,2 , Janesh Karnati 2 , Justin Virojanapa 1,2 , Joseph Cheng 1,2 , Rani Nasser 1,2 1 University of Cincinnati Medical Center, Neurosurgey, Cincinnati, United States, 2 University of Cincinnati College of Medicine, Cincinnati, United States, 3 Loyola University Medical Center, Maywood, United States Introduction: Deep vein thrombosis (DVT) and pulmonary emboli (PE) are complications frequently associated with elective spine surgery. Surgeons must weigh the risk of patients developing pulmonary emboli if thromboprophylaxis is not administered with the risk of developing a possible post-operative epidural hematoma from thromboprophylaxis. Current guidelines by governing bodies regarding the use of DVT prophylaxis in elective spine surgery are generally inconclusive and based on limited evidence. The aim of this study was to evaluate if there is a difference in the rate of DVT, PE, or postoperative hematoma requiring re-operation with administration of DVT prophylaxis in elective spine surgery. Material and Methods: We conducted a single-institution, retrospective cohort study examining the rates of DVT, PE, and hematoma formation requiring surgical evacuation in patients undergoing elective spinal surgery by neurosurgeons or orthopedic surgeons from July 2020 to July 2022 at our institution. Cases for trauma, infection, and tumor were excluded. Known preoperative DVT, presence of pre-existing comorbidity requiring resumption of anticoagulation within 3 days of surgery, and discharge home the day of surgery also met exclusion criteria. For patients who underwent surgery more than once during the study, only their index case was considered for analysis. Length of operative time (minutes), BMI, gender, tobacco use, length of stay, presence of diabetes mellitus (DM), and presence of coronary artery disease (CAD) or peripheral vascular disease (PVD) were included in data collection. Multivariate logistic regression analysis was performed to evaluate the primary outcomes. Chi square analysis was performed to evaluate categorical variables. Results: A total of 1236 patients met study criteria. 679 patients (54.9%) received DVT prophylaxis, while 557 patients (45.1%) did not. Of patients receiving DVT prophylaxis, 621 (91.5%) had prophylaxis administered within 24 hours of surgery, while 58 (8.5%) had prophylaxis first administered 72 hours after surgery. 25 patients receiving prophylaxis developed a DVT (3.7%), while 1 patient developed a DVT in the non-treatment group (0.2%). Of the 6 patients who returned to the OR for evacuation of epidural hematoma, 3 (50%) had received DVT prophylaxis. Multivariate regression analysis of all patients showed no significant effect of DVT prophylaxis on development of DVT (p = 0.19) or PE (p = 0.19), but did demonstrate that longer operative times (p < 0.001), age (p = 0.04), and LOS (p < 0.001) were significantly associated with increased rates of both DVT and PE. Similarly, there was no significant increase in rate of return to OR for hematoma for patients who received DVT prophylaxis (p = .54), but administration of early prophylaxis rendered a significantly higher rate of hematoma compared to late prophylaxis (p < 0.001). Conclusion: Our data supports the conclusion that DVT prophylaxis does not significantly impact rate of DVT or PE formation in elective spine surgery. Earlier administration of prophylaxis was associated with higher rates of hematoma requiring reoperation, though this only held true for specific surgical groups during subgroup analysis. Ultimately, our findings support pursuing further studies on whether DVT prophylaxis is necessary in elective spine surgery. Jeremy Heard 1 , Jonathan Dalton 2 , Rachel Huang 2 , Otitochukwu Ezeonu 2 , Bryan Nardone 3 , Ryan Dwosh 4 , Chris Kepler 2 1 Brown University, Orthopaedic Surgery, Providence, United States , 2 Rothman Orthopaedic Institute, Philadelphia, United States , 3 Thomas Jefferson University, Anesthesiology, Philadelphia, United States , 4 University of Vermont Medical Center, Anesthesiology, Burlington, United States Introduction: As the number of patients undergoing lumbar spine surgery continues to increase, it becomes increasingly important to understand factors that can improve surgical outcomes. Recent research has explored the effects of pharmacologic agents administered to reverse neuromuscular blockade induced during general anesthesia. Two examples of these agents include 1) sugammadex and 2) the combination of neostigmine (acetylcholinesterase inhibitor) and glycopyrrolate (antimuscarinic agent). These two agents work via completely different mechanisms, with sugammadex having a theoretical side effect advantage due to not inhibiting acetylcholinesterase. While these agents have been studied in various surgical specialties, there is limited literature examining their effects during spine surgery. The purpose of this study is to evaluate the inpatient complication profiles of patients receiving neuromuscular blockade reversal via sugammadex compared to those receiving neostigmine with glycopyrrolate. Material and Methods: All adult patients (≥ 18 years old) who underwent a primary one- to two-level posterior lumbar fusion between 2018-2021 were retrospectively identified. Patient demographics, surgical characteristics, surgical outcomes, and the type of neuromuscular blockade reversal agent used (sugammadex versus neostigmine/glycopyrrolate (NG)) were collected through a combination of Structured Query Language search and manual chart review. Appropriate statistical analysis was conducted, including multivariate linear regression. Alpha was set at 0.05. Results: Amongst the 549 patients identified, 151 (27.5%) received sugammadex and 398 (72.5%) received NG. Surgery duration was longer in the NG group (182 ± 55.9 vs. 174 ± 55.9 minutes, p = 0.039), however no other demographic or surgical differences were noted between groups. Patients who received NG had a greater incidence of overall complications (124 (31.2%) vs. 30 (19.9%); p = 0.012), and experienced a higher rate of overall complications per person (0.40 ± 0.66 vs. 0.28 ± 0.62; p = 0.046). For patients who received NG, incidence (76 (19.1%) vs. 17 (11.3%); p = 0.040) and rate per person (0.23 ± 0.50 vs. 0.13 ± 0.37; p = 0.009) of cardiac complications, in particular, were higher. Regression analysis indicated that sugammadex was independently associated with a reduction in inpatient complications (estimate = -0.124; p = 0.045), while Elixhauser comorbidity index was associated with an increase in inpatient complications (estimate = 0.073; p < 0.001). Conclusion: This study indicates that the neuromuscular blockade reversal agent, sugammadex, is independently associated with an overall reduction in complications compared to NG amongst patients undergoing lumbar fusion. Additionally, the use of sugammadex was associated with a decreased rate of cardiac complications compared to NG. This finding is particularly significant because many lumbar spine surgeries are performed with patients in the prone position, which can elevate abdominal pressure and impose additional strain on the heart. Therefore, sugammadex may be a superior neuromuscular reversal agent in terms of reducing cardiac complications. These findings may be related to the mechanism of action of sugammadex, which avoids acetylcholinesterase inhibition. However additional research is necessary before definitive clinical recommendations can be made. Stevin Lu 1 , Wyatt Vander Voort 2 , Zachary Booze 2 , Dagoberto Pina 2 , Hania Shazad 2 , Yashar Javidan 2 , Rolando Roberto 2 , Hai Le 2 1 Creighton School of Medicine, Omaha, United States , 2 UC Davis Medical Center, Sacramento, United States Introduction: Patients are commonly discharged using a transitional care approach to assist with recovery following elective lumbar fusion surgery. Discharge disposition has previously been reported to be associated with future emergency department (ED) or readmission encounters following surgery, which can lead to increased costs and low patient satisfaction. However, this topic remains unclear in patients undergoing elective lumbar fusion surgery. This study assesses how discharge disposition can affect rates of return to ED or readmission when controlling for patient and clinical variables. Material and Methods: Patients aged ≥ 18 years undergoing elective lumbar or lumbosacral fusion surgery for degenerative pathology from 2018 to 2022 at a single academic institution were included. Patients undergoing surgery for trauma, tumor, and/or deformity were excluded. A retrospective review of medical records was conducted. Patient and surgical characteristics including age, gender, American Society of Anesthesiology (ASA) score, Charlson Comorbidity Index (CCI), postoperative complications (pneumonia, wound infection, wound dehiscence, bacteremia), payer status, numbers of levels fused, fusion to pelvis, hospital length of stay, and discharge disposition were obtained. Patients were classified into 2 groups: Home health (N = 414) and Skilled Nursing Facility (SNF)/Inpatient Rehabilitation Facility (IRF) (N = 81). Return to the emergency department and readmission visits within 3 months postoperatively were recorded. Univariate and multivariate regression models were used to identify independent factors associated with ED presentation or readmission (p < 0.05). Results: 495 patients were included. 268 (54.1%) of the patients were male. Average age and body mass index (BMI) were 65.3 ± 11.2 years and 30.9 ± 9.2, respectively. Average ASA and CCI scores were 2.7 ± 0.5 and 3.4 ± 2.0, respectively. The overall readmission rate was 15.2% and the overall rate of ED utilization was 19.0%. Bivariate analysis for readmissions indicated significant differences in discharge status, postoperative complications, age, gender, payer status, ASA scores, length of hospital stay and CCI (p < 0.05). Bivariate analysis for return to ED had significant differences in postoperative complications, ASA scores, CCI length of hospital stay (p < 0.05). Patients with a greater number of levels fused and fusion to pelvis also had higher rates of return to ED and readmission to the hospital postoperatively (p < 0.05). In the univariate model looking at discharge disposition only, patients who were discharged to SNF or IRF had 3.81 (p < 0.01) times higher odds of readmission and 1.51 (p = 0.15) times higher odds of return to ED than patients who were discharged to home. After adjusting for potential confounding effects from postoperative complications, gender, payor plan, ASA score, fusion to pelvis, and CCI using a multivariate model, the odds ratio for readmission and return to ED were 2.12 (p = 0.021) and 0.97 (p = 0.927), respectively. Conclusion: This study demonstrates that patients who were discharged to either SNF or IRF following their hospitalization often had poorer outcomes with higher odds of readmission to the hospital within 3 months when adjusting for patient and surgical variables. However, this association was not seen for ED visits. The information found in this study can assist with future considerations prior to the discharge of patients to improve postoperative outcomes following lumbar fusion spine surgery. Sharif Ahmed Jonayed 1 1 National Institute of Traumatology and Orthopaedic Rehabilitation, NITOR, Spine Surgery, Dhaka, Bangladesh Introduction: Scoliosis, a prevalent spinal deformity, spans various age groups and demands clinical attention. While commonly observed in teenagers, it also affects extreme age groups & adults. Timely surgical intervention yields favorable functional and radiological outcomes, emphasizing the importance of correction and cosmesis. Objective: This study aims to assess the radiological and functional outcomes of scoliosis surgery utilizing pedicle screws, rods, and spinal osteotomies through a posterior-only approach. Materials and Methods: A prospective case series comprising 28 scoliosis patients treated between July 2018 and June 2022 at NITOR and a private hospital. Preoperative assessments included investigations and clinical evaluations. Patients and attendants received comprehensive explanations about the procedure, associated risks, and benefits. Radiological outcomes were measured using pre- and postoperative Cobb angle assessments, determining the percentage correction. The lower instrumented vertebra served as the neutral vertebra (when indicated), with its level recorded. Functional outcomes were evaluated using the Scoliosis Research Society (SRS) 22 r Patient questionnaire. Results: Among the 28 patients, 19 were male and 9 female, with an average age of 17.7 years. The mean preoperative Cobb angle was 79°, reducing to 20° postoperatively, signifying a 78% correction. Average follow-up duration was 2.6 years. One major complication involved postoperative neurological deterioration, while two minor complications were related to wound infection. SRS scores indicated favorable outcomes: pain (4.3), self-image (4.1), functional status (4.2), mental status (3.6), and satisfaction (4.5). No significant correlation was found between scoliosis correction percentage and functional outcome. Patients with higher preoperative Cobb angles tended to experience improved functional and mental statuses postoperatively. No association was observed between the lower instrumented vertebra and functional outcomes. Conclusion: Posterior instrumentation combined with spinal osteotomies emerges as a reliable, safe, and effective technique for scoliosis treatment when surgery is warranted. Successful outcomes hinge on thorough preoperative assessment planning and adequate training in spinal deformity correction. Keywords: scoliosis, spinal deformity, SRS 22 r Patient questionnaire, posterior instrumentation, spinal osteotomies. Angel Paz 1 , Masato Tanaka 2 1 Instituto de Ortopedia Avanzada, San Pedro Garza Garcia, Mexico , 2 Okayama Rosai Hospital, Vice President, Head of Orthopedic Surgery, Okayama, Japan Introduction: Occipitocervical (OC) and atlantoaxial (AA) fusion are established techniques for upper cervical instability. However, there is very little evidence comparing both methods. Material and Methods: This study included 90 patients who underwent upper spinal fusion surgery for mechanical instability (OC fusion 38 patients, 58.7 yrs; AA fusion 52 patients, 62.8 yrs). Surgical outcomes were evaluated by surgical time, intraoperative blood loss, postoperative complications, and revision surgery rate. Radiographic assessments were performed to identify screw malposition, rod breakage, and nonunion. Results: The OC group had significantly longer surgical time (175.4 mins vs. 150.7 mins, p-0.020), higher complication rate (41.6% vs. 11.1%, p < 0.0001), and higher revision surgery rate (22.2% vs. 3.7%, p = 0.0007) than the AA group. The reoperation rate was 22.2% (8/36) in the OC group and 3.9% (2/52) in the C12 group, demonstrating a statistically significant difference between the two groups (p = 0.0073). Regarding blood loss, the OC group had an average blood loss of 223.5 ml compared to 307.9 ml in the OC group, with no significant difference in ABL (p = 0.947). Conclusion: While OC fusion is indispensable for certain patients, particularly those with basilar invagination, its higher risk profile compared to AA fusion warrants careful consideration. Vitor Viana Bonan de Aguiar 1 , Emilson Camapum 1 , Israel Buzzatti Queiroz 1 , Alex Oliveira de Araujo 2 , Ricardo de Amoreira Gepp 1 , Asdrubal Falavigna 3 1 Sarah Network of Rehabilitation Hospitals, Neurosurgery, Brasília, Brazil , 2 Sarah Network of Rehabilitation Hospitals, Orthopaedics, Brasília, Brazil , 3 University of Caxias do Sul, Neurosurgery, Caxias do Sul, Brazil Introduction: Open-door cervical laminoplasty (CL) is an option for treating degenerative cervical myelopathy. In general, the procedure is indicated when there is no kyphosis, more than two levels of compression, and calcification of the posterior longitudinal ligament. A possible complication of CL observed postoperatively is paresis related to the C5 root. There is a discussion about the possible mechanisms that lead to C5 paresis (PC5). The study evaluated the stenosis of the C5 root foramen, preoperative clinical conditions, and surgical time as possible risk factors for triggering PC5. Material and Methods: Retrospective study. Data collection in electronic medical records. A total of 421 patients were included in the study, all > 18 years old from January 2017 to January March 2022. Data on age and preoperative clinical conditions classified by the American Society of Anesthesiologists (ASA) were collected. All patients should have had computed tomography (CT) performed preoperatively. The diameter of the C5 root foramen was measured bilaterally in an axial CT scan, measuring the distance from the uncinate process to the superior articular process. Fifteen patients with (PC5) were identified, but two patients did not undergo preoperative CT. From the population of 421 CL patients and 13 patients with PC5, a sample calculation was performed with a confidence interval of 95%, sampling error of 5%, sampling power of 80%, the significance level of 5%, reaching a population of 58 patients for evaluation of foramina. The demographic profile and clinical data were characterized using absolute frequency, relative frequency, mean and standard deviation. Data normality was verified using the Kolmogorov-Smirnov test. The distribution of the sample profile of the groups was tested using Pearson's chi-square test and Student's t-test. ROC curve analysis was performed to detect the cut-off, sensitivity, and specificity of C5 paresis. The significance level adopted was 5% (p = 0.05). Results: The parameters: Age (years) in the normal group (GN) 58.58 ± 11.60 and Group with C5 paresis (GP5) 56.92 ± 16.30 and the total 58.21 ± 12.66. Surgery time (minutes): GN = 128.53 ± 42.72, GP5 = 171.54 ± 81.10 and total 138.17 ± 55.86 p = 0.01. Diameter of C5 root foramina (mm): GN = 2.77 ± 0.54, GP5 2.37 ± 0.47 and total 2.68 ± 0.55 p = 0.02. ASA 2 GN = 37 (82.2%) GP5 = 9 (69.2%) and ASA 3 = GN 8 (17/8%) and 4 (30.8%). The ROC Curve Analysis of the groups as a function of the mean foramen size: area of ​​0.71, criterion < 2.2 mm; p = 0.01. Conclusion: The study shows that the greater the stenosis of the foramen, the greater the possibility of C5 paresis. The chances also increase the longer the surgical time. These results associated with future studies may contribute to understanding this complication. Guilherme Pajanoti 1 , Matheus Castanheira 1 , Delio E. Martins 1 , Michel Kanas 1 , Marcelo Wajchenberg 1 , Nelson Astur 1 1 Hospital Israelita Albert Einstein, Sao Paulo, Brazil Introduction: Low back pain and sciatica account for about 40% of work absences. Treatments include rest, analgesia, physical therapy, exercises, interventional procedures, and spinal surgery. Lumbar epidural steroid injections and facet blocks are increasingly used for both diagnostic and therapeutic purposes. While most complications are minor (2.4% to 9.6%), serious complications like infection, hematoma, and spinal cord infarction can occur. This case involves a perineural hematoma causing acute radiculopathy and requiring urgent surgical decompression. Material and Methods: A 55-year-old woman presented with a 7-month history of low back pain radiating to her right thigh and leg, unresponsive to analgesia and physical therapy. Her physical examination was normal. MRI showed a scoliotic posture of the lumbar spine with minimal degenerative retrolisthesis from L2 to L4, diffuse disc degeneration (worse at L4-L5 and L5-S1) with Modic type I changes, bilateral disc bulging at L3-L4, L4-L5, and L5-S1, and multilevel facet hypertrophy. Given persistent pain, lumbar facet injections from L2 to S1 bilaterally and right L3 and L4 nerve root injections were performed under fluoroscopic guidance. During the procedure, Omnipaque contrast (0.5 mL per level) was injected, followed by a solution containing 1.5 mL of triamcinolone 20 mg/mL, 1.5 mL of ropivacaine 7.5 mg/mL, and 2 mL of 0.9% saline, administered in fractional doses. The procedure was uneventful, and the patient remained asymptomatic postoperatively. However, on the third day post-injection, she reported progressive weakness in her left leg, sensory loss in the L3 dermatome, and gait dysfunction. An urgent MRI with gadolinium revealed an abnormal signal in the left L3-L4 foraminal region, compressing the left L3 nerve root, with peripheral inflammatory enhancement. Results: Infection and extruded disc herniation were considered unlikely etiological factors based on imaging findings and symptom timing, with hematoma being the primary diagnostic hypothesis. The patient underwent urgent left L3-L4 tubular lumbar decompression surgery. Pathological examination confirmed the diagnosis of hematoma, revealing fibrous connective tissue fragments associated with areas of organizing hemorrhage. On the first postoperative day, the patient's symptoms improved, returning to baseline within a month, with normalization of strength, sensation, and relief from pre-procedural pain. Based on a literature review, the hematoma in this case may have been caused by increased epidural pressure from contralateral foraminal injection or direct needle injury during facet infiltration at the same level as the hematoma. Although the needle entered the right L3-L4 intervertebral foramen, the epidural hematoma was located in the contralateral foraminal and extra-foraminal regions, with facet infiltration potentially contributing to the hematoma’s formation. Conclusion: Physicians performing these procedures must be vigilant for epidural hematoma, as it can lead to permanent damage. In addition to direct vascular injury, hematomas can result from increased pressure during medication injection, even without signs of bleeding or anticoagulant use. Prompt evaluation with MRI is essential, as case reports suggest the need for immediate surgical decompression. The sooner the intervention, the better the outcomes, with an inverse relationship between symptom duration and recovery. Juan Cárdenas 1,2 , Thais Cunha 3 , Rachel Boy 4 , Alfredo Guiroy 5 6 , Cristiano Menezes 1 2 7 1 Columna Institute, Belo Horizonte, Brazil , 2 Hospital Vila da Serra, Orthopedics/Spine Surgery, Belo Horizonte, Minas Gerais, Brazil , 3 Hospital Vila da Serra, Physiotherapy, Belo Horizonte, Minas Gerais, Brazil , 4 Hospital Vila da Serra, Neurology, Belo Horizonte, Minas Gerais, Brazil , 5 Clinica de Cuyo, Mendoza, Argentina , 6 Elite Spine Health and Wellness Center, Spine Surgery, Florida, United States , 7 Federal University of Minas Gerais (UFMG), Locomotor System, Belo Horizonte, Brazil Introduction: Anterior lumbar interbody fusion surgeries in lateral decubitus (L-ALIF) allow for combined 360º reconstructions, considerably reducing surgical time. However, it is critical to know how to recognize and treat possible related complications in a timely manner, making the use of intraoperative neuromonitoring (IONM) a great ally in these situations. This case aims to report a rare and unusual form of arterial injury during an L-ALIF procedure associated with IONM alterations. Material and Methods: Case report. Results: An 81-year-old patient with a history of chronic low back pain with progressive worsening, bilaterally radiating to the lower limbs and limping gait, refractory to conservative treatment due to degenerative lumbar scoliosis and multilevel stenosis has been reviewed. A three level lateral lumbar interbody fusion (LLIF) of L2-L5 and L-ALIF L5-S1 with percutaneous posterior instrumentation of L2-S1 was planned and performed using multimodal IONM (IONMm). During the intraoperative period, a significant alteration in the amplitude of the right lower limb's motor evoked potentials (MEPs) was evident only after the metabolization of muscle relaxants after the anterolateral approaches, with partial recovery by the end of the surgery. On the first postoperative day, the patient developed sensory and motor alterations in the right lower limb, initially suggesting possible sympathetic plexus dysfunction or injury/irritation of the lumbar plexus. However, after angiography, dissection of the right common iliac artery was evident due to injury to the intima, so angioplasty with successful revascularization was performed. Despite rapid management of the complication, the patient developed ischemic necrosis of the anterolateral aspect of the right leg, requiring multiple fasciotomies and debridements, with subsequent muscle flap. Conclusion: Based on the present case and its evolution, we emphasize the importance of using IONMm in combined anterolateral surgeries and that at the slightest suspicion of any unusual alteration of the IONMm or that is not explainable intraoperatively, vascular etiology should be considered among the primary differential diagnoses with early multidisciplinary management as complications can be devastating. Daniel de Reus 1,2 , Harmen Kuijten 2 , Priyanshu Saha 3 , Diego Abelleyra Lastoria 3 , Aliénor Warr-Esser 3 , Charles Taylor 3 , Olivier Groot 2 , Darren Lui 3 , Jorrit-Jan Verlaan 2 , Daniel Tobert 1 1 Massachusetts General Hospital, Boston, United States , 2 University Medical Center Utrecht, Utrecht, Netherlands , 3 St. George's Hospital, London, United Kingdom Introduction: A machine learning (ML) model was recently developed to predict massive intraoperative blood loss (> 2500 mL) during posterior decompressive surgery for spinal metastasis that performed well on external validation within the same region in China. We sought to externally validate this model across new geographic regions (North America and Europe) and patient cohorts. Material and Methods: Multi-institutional retrospective cohort study. We retrospectively included patients 18 years or older who underwent decompressive surgery for spinal metastasis across three institutions in the United States, the United Kingdom, and the Netherlands between 2016 and 2022. Inclusion and exclusion criteria were consistent with the development study with the additional inclusion of (1) patients undergoing palliative decompression without stabilization, (2) patients with multiple myeloma and lymphoma, and (3) patients who continued anticoagulants perioperatively. Model performance was assessed by comparing the incidence of massive intraoperative blood loss in our cohort to the predicted risk generated by the ML model. Blood loss was quantified in 6 ways in addition to the formula from the development study as no gold standard exists, and the method in the development paper was not clearly defined. We estimated blood loss using the anesthesia report and calculated it using transfusion data and preoperative and postoperative hemoglobin levels. The following five input variables required for risk calculation by the ML model were manually collected: tumor type, smoking status, ECOG score, surgical process, and preoperative platelet count. Model performance was assessed with accuracy, Brier score, area under the curve (AUC), and calibration intercept & slope for our total cohort, and for the North American and European cohorts separately. A sub-analysis, excluding the additional included patient groups, assessed the predictive model's performance with the same inclusion and exclusion criteria as the development cohort. Results: A total of 880 patients were included with a massive blood loss range from 5.3% to 18% depending on which quantification method was used. Using the most favorable quantification method, the predictive model overestimated risk in our total validation cohort and scored poorly on overall performance (accuracy: 0.477, Brier score: 0.278), discrimination (AUC: 0.631 [95% CI: 0.583, 0.680]), and calibration (intercept: -2.082 [95% CI: -2.285, -1.879], slope: 0.283 [95% CI: 0.173, 0.393]). Similar poor performance results were observed in the sub-analysis excluding the additional included patients (n = 676) and when analyzing the North American (n = 539) and European (n = 341) cohorts separately. Conclusion: To our knowledge, this is the first published external validation of a predictive ML model within orthopedic surgery to demonstrate poor performance. This poor performance might be attributed to overfitting and sampling bias as the development cohort had an insufficient sample size, and distributional shift as our cohort had key differences in predictive variables used by the model. Our results emphasize the importance of extensive validation in different geographical areas before implementation in clinical practice, as untested models can cause more harm than good. Furthermore, addressing known biases and pitfalls in ML model development - such as sampling bias, overfitting, ensuring adequate sample size, and distributional shift - is crucial. Nader Hejrati 1 , Benjamin Martens 2 , Bernhard Jost 2 , Oliver Bozinov 1 , Martin Stienen 1 1 Spine Center of Eastern Switzerland, Cantonal Hospital of St. Gallen & Medical School of St. Gallen, Department of Neurosurgery, Cantonal Hospital of St. Gallen & Medical School of St. Gallen, St. Gallen, Switzerland , 2 Spine Center of Eastern Switzerland, Cantonal Hospital of St. Gallen & Medical School of St. Gallen, Department of Orhopaedics and Traumatology, Cantonal Hospital of St. Gallen & Medical School of St. Gallen, St. Gallen, Switzerland Introduction: Expandable spacer technology is innovative and increasingly considered for lumbar interbody fusion. Outcomes of expandable cages have only been infrequently reported. While cage subsidence has been associated with the use of expandable spacers, data on the rates of cage collapse is sparse. Herein, we present our single-center experience with a specific expandable transforaminal lumbar interbody fusion (TLIF) / posterior lumbar interbody fusion (PLIF) device. Material and Methods: In this retrospective, single-center observational cohort study we reviewed consecutive PLIF/TLIF patients using the Catalyft TM PL and PL40 expandable titanium interbody implant (Medtronic, Minneapolis (USA)) between 07/2022-11/2023. We recorded patient demographics, surgical parameters, adverse events, radiological parameters and clinical outcomes according to the MacNab criteria. Results: We identified 57 patients (mean age 68.7 ± 11.2 years; 52.6% female; mean BMI 25.4 ± 4.4kg/m 2 ; 26.3% smokers; 29.8% with osteoporosis), in which 98 Catalyft TM spacers were implanted, mostly at L4/5 (n = 38; 38.8%) and L5/S1 (n = 33; 33.7%) for degenerative (n = 48; 84.2%), deformity (n = 7; 12.3%) or other indications (n = 2; 3.5%). We noticed secondary collapse of 21 (21.4%) spacers in 12 patients (21.0%) occurring after a mean time of 5.1 ± 4.9 months postoperatively. No statistically significant differences were observed in terms of patient-specific (age, sex, BMI, pathology) and surgery-related risk factors (previous surgery involving same segment, spinal level, type of interbody spacer used) between groups. Pseudarthrosis was evident in eight patients (14.0%), of which four (7%) required revision surgery. Clinical outcome at last follow-up (mean 6.6 ± 4.2 months) was excellent/good in 31 (54.4%), fair in 15 (26.3%) and poor in seven patients (12.3%). Conclusion: We provide a critical analysis of our series of patients with use of a specific type of expandable interbody spacer. We noticed failure and secondary collapse in an unacceptably high number of implants, some of which required revision surgery. Louise Brage 1 , Lukas Bobinski 2,3 , Patricia Hägglund 1 , Eva Levring-Jäghagen 4 , Thorbjörn Holmlund 5 1 Umeå University, Department of clinical sciences, Speech and Language Pathology, Umeå, Sweden , 2 Umeå University, Department of Diagnostics and Intervention, Umeå, Sweden , 3 Umeå University Hospital, Department of Orthopedics, Spine Unit, Umeå, Sweden , 4 Umeå University, Department of Odontology, Oral and Maxillofacial Radiology, Umeå, Sweden , 5 Umeå University, Department of Clinical Sciences, Otorhinolaryngology, Umeå, Sweden Introduction: Dysphagia is one of the most common adverse effects after anterior cervical spine surgery (ACSS), with an incidence of up to 79% during the first week after surgery. Although many patients recover within three months, few studies have investigated the long-term effect of ACSS on dysphagia and swallowing function. Swallowing dysfunction may lead to several secondary complications, such as aspiration pneumonia, malnutrition, dehydration, and prolonged stay in intensive care. Hence, early diagnosis and treatment are of great importance. The gold standard method for diagnosing objectively measured dysphagia is either with flexible endoscopic evaluation of swallowing (FEES) or videofluoroscopic evaluation of swallowing (VFS). Regrettably, most studies on this topic are retrospective and mostly utilize questionnaires, the method with the lowest sensitivity for correct diagnosis of objectively measured dysphagia. Materials and Methods: This ongoing prospective, observational cohort study is conducted in collaboration between the departments of speech and language pathology, ear, nose and throat, oral and maxillofacial radiology and spine surgery at Umeå University Hospital. The goal of the study is to identify the incidence and natural course of dysphagia/dysfunction in patients who undergo ACSS above the level of Th1. The swallowing function is assessed with FEES within 14 days after surgery (baseline). Patients with postoperative swallowing dysfunction are followed up within four weeks with repeated assessment using FEES. All enrolled patients treated with ACSS, regardless of the swallowing status at baseline, undergo a 12 months follow-up with FEES. Preliminary Results: The interim analyzes included 52 participants, assessed at baseline and 12 months post-surgery (27 women and the median age was 67 years, range 37-85 years). Of these, 36 participants had surgery due to degenerative cause (20 women, the median age was 65 years, range 42-78 years), 10 participants had surgery due to trauma (5 women, median age was 70 years, range 37-85 years) and 6 participants had surgery due to other or mixed etiology. For the total group of participants, the procedure type of surgery varied; 46 participants underwent anterior discectomy with fusion, 5 participants corpectomy and fusion, and one participant underwent a combination of both. The surgery level varied from one-level (19 participants), two-level (16 participants), three-level (14 participants) and four-level (3 participants). Four participants required additional posterior stabilization. For the total group of participants, dysphagia was present in 32 participants (62%) according to FEES-assessment at baseline. Of these, dysphagia was still observed in 12 participants (38%) at follow-up 4 weeks post-surgery. At the follow-up assessment 12 months post-ACSS of all enrolled patients, 20 participants (38%) demonstrated dysphagia. Notably, at the follow-up assessment 12 months post-surgery, 6 participants (12%), who did not have swallowing dysfunction at baseline, developed dysfunction one year after surgery. All these 6 participants were operated due to degenerative spine disease. Conclusion: Our preliminary findings indicate a high incidence of objectively measured dysphagia after ACSS, highlighting the importance of early identification and management to minimize adverse outcomes and improve patient rehabilitation. Luke Jouppi 1,2 , Zeyad Daher 1 , Bryan Anderson 1,2 , Clifford Pierre 1,2 , Donald Davis 1,2 , Neel Patel 1,2 , Julius Gerstmeyer 1,2,3 , Gautam Rao 1 , Daniel Norvell 4 , Giorgio Cracchiolo 1 5 , Amir Abdul-Jabbar 1,2 , Rod Oskouian 1,2 , Jens Chapman 1,2 1 Seattle Science Foundation, Seattle, United States , 2 Swedish Neuroscience Institute, Seattle, United States , 3 Ruhr University Bochum, BG University Hospital Bergmannsheil, Department of General and Trauma Surgery, Bochum, Germany , 4 Spectrum Research Consulting, Tacoma, United States , 5 Humanitas Research Hospital, Milan, Italy Introduction: Distal junctional kyphosis (DJK) and distal junctional failure (DJF) are known complications of adult multilevel spinal fusion surgery. Previous literature has extensively investigated proximal junctional kyphosis (PJK) and proximal junctional failure (PJF), but DJK and DJF are relatively under-studied. This study investigates the association between bone mineral density (BMD) and DJK/DJF via a Systematic Review (SR) and Meta-Analysis (MA). Methods: A literature search was conducted across PubMed, Cochrane, Web of Science, Embase, and Scopus to find studies reporting DJK, DJF, and BMD. A 12-month minimum follow-up and radiographic biomarker for BMD (Hounsfield units {HU} or a T-score) individually reported for each patient type were required for inclusion. Studies that did not report individualized biomarkers but provided averaged estimates of the effect of BMD on DJK/DJF development were used for SR. Results: Our search yielded 12 unique studies with 1,094 patients, of which five studies with a total of 519 patients were suitable for comparison by MA. Patients who developed DJK/DJF had significantly lower HUs (113.17 ± 33.86) than patients who did not develop DJK/DJF (142.51 ± 41.39). No significant difference was found with regards to DEXA measurements, age, or BMIbetween patients who did and did not develop DJK/DJF. Conclusions: Patients who developed DJK/DJF had significantly lower CT-measured HU as compared to those without DJK/DJF. Our findings highlight the potential importance of BMD evaluation with CT prior to multilevel spine fusion surgery, though further research would be helpful to evaluate the significance of DEXA-based BMD measurements on DJK/DJF development. Rowen Lin 1 , Evan Minami 1 , Jahan Jazayeri 1 , Matt Sung 1 , Kevin Mo 2 , William Fang 2 , Haley Nadone 3 , Sohaib Hashmi 3 , Don Park 3 , Yu-po Lee 3 , Nitin Bhatia 3 , Hao-Hua Wu 3 1 Touro University Nevada, Henderson, United States , 2 Valley Hospital Medical Center, Las Vegas, United States , 3 University of California, Irvine, Department of Orthopedic Surgery, Orange, United States Introduction: Adjacent segment disease (ASD) is a complication that occurs in vertebrae adjacent to a site of spinal fusion, often necessitating revision surgery when nonoperative treatments fail. There is ongoing debate regarding the optimal surgical approach for managing ASD, specifically whether decompression alone or decompression combined with fusion yields better outcomes. This systematic review aims to provide a comprehensive comparison of these two surgical strategies by examining reoperation rates, reasons and timing for reoperation, important intraoperative factors, and changes in pain and functionality. Material and Methods: A systematic review was conducted by searching PubMed, Embase, and Cochrane Library databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of evidence was assessed using the Newcastle-Ottawa Scale (NOS). Statistical analyses were performed using STATA software to synthesize the data and compare outcomes between the two surgical strategies. Results: The review included 15 articles with a total of 406 patients. For the decompression-only group, the reoperation rate was 16.2% (range: 0% - 33%). The average operative time was 81.6 minutes (range: 52.7 - 96 minutes), and the average hospital length of stay was 3.88 days (range: 1.5 - 5.7 days). The mean improvement in pain (VAS) was 4.91, and functionality (ODI) improved by 32.67 points. In contrast, the decompression plus fusion group had a lower reoperation rate of 9% (range: 0% - 26.3%). The average operative time was 135.3 minutes (range: 60.6 - 214.1 minutes), and the average hospital stay was 4.81 days (range: 1.8 - 9.5 days). The mean improvement in pain (VAS) was 3.65, and functionality (ODI) improved by 22.25 points. Only one study directly compared decompression alone with decompression plus fusion. Conclusion: Decompression with simultaneous lumbar fusion is associated with a lower rate of reoperation compared to decompression alone, but it also involves a longer operative time and extended hospital stay. Conversely, decompression alone results in a more significant improvement in pain and functionality. The scarcity of direct comparisons between the two approaches highlights the need for further research to determine the most effective surgical strategy for treating ASD. Future studies should aim to provide more direct comparisons and long-term outcomes to guide clinical decision-making. Nan Wu 1 , Jianle Yang 1 , Ziquan Li 1 , Shengru Wang 1 , Jianguo Zhang 1 , Deciphering Disorders Involving Scoliosis and COmorbidities Study Group 1 1 Peking Union Medical College Hospital, Beijing, China Introduction: Early-onset scoliosis (EOS) is defined as a manifestation of scoliosis before the age of ten. Operative treatment of EOS can be very challenging with a variety of perioperative complications. The identification of risk factors associated with complications is essential for the management of patients with EOS. Material and Methods: Patients with EOS who underwent spinal surgery with a minimum of five-year follow-up after the initial surgery were included, as part of the Deciphering disorders Involving Scoliosis and COmorbidities (DISCO) study. Standard demographic information, radiographical data, genetic testing results, and surgical records were reviewed. Potential risk factors were identified by univariate analysis and multivariate logistic regression. In addition, a subgroup analysis of syndromic EOS patients was performed. Results: A total of 299 patients were recruited. For 252 of the patients, the etiology of scoliosis was congenital; for 41, syndromic; for four, idiopathic; and for two, neuromuscular. The mean postoperative follow-up was 103.0 months (range, 64 to 217 months). Patients with syndromic EOS were molecularly diagnosed by pathogenic variants in 29 genes. A total of 73 (24.4%) patients developed postoperative complications. 27 of the patients experienced implant-related complications, 27 had alignment-related complications, ten had wound-related complications, and nine had other complications. The univariate analysis revealed that the age, etiology, molecular classification, curvature number, and surgical procedure were significantly associated with the development of complications (p < 0.1). Multivariate analysis revealed that the age (odds ratio [OR], 0.888; 95% CI, 0.818, 0.965; p = 0.005), syndromic EOS caused by chondrogenesis-related genes (odds ratio [OR], 0.164; 95% CI, 0.044, 0.618; p = 0.008), fusion levels (odds ratio [OR], 2.678; 95% CI, 1.236, 5.806; p = 0.013), curvature number (odds ratio [OR], 2.6414; 95% CI, 1.158, 5.899; p = 0.021), and surgical procedure (odds ratio [OR], 2.434; 95% CI, 1.104, 5.368; p = 0.028) were the independent risk factors for the complications. After subgroup analysis, we found that the incidence of complications in syndromic EOS was higher than that in non-syndromic EOS. Conclusion: By integrative analysis of clinical and genetic information, we found that younger age at index surgery, the diagnosis of syndromic EOS, fusion levels greater than 4, surgical procedure with growing-rod implantation, and curvature number greater than 2 were independent risk factors for complications following surgical treatment in patients with EOS. Of note, our findings revealed that patients with syndromic EOS experience a higher rate of complications. This underscores the importance that a comprehensive genetic analysis of EOS population may play a vital role in clinical care. Henry Avetisian 1 , William Karakash 1 , Chimere Ezuma 1 , Jeffrey C. Wang 1 , Raymond Hah 1 , Ram Alluri 1 1 Keck School of Medicine of USC, Department of Orthopaedic Surgery, Los Angeles, United States Introduction: COVID-19 has been associated with an increased risk of severe postoperative complications across various surgical specialties. In spine surgery, recent studies have reported higher rates of venous thromboembolism (VTE), sepsis, pneumonia, and readmissions in patients who contracted COVID-19 shortly before their procedure. While a two-week delay for elective spine surgery has been suggested, no formal guidelines exist, and the optimal timing remains unclear. This retrospective analysis of a large national database examines the complications of lumbar spine fusion in patients with COVID-19 within 14 days before surgery, aiming to clarify the risks and appropriate timing for surgery post-infection. Methods: A retrospective analysis was conducted using the PearlDiver Mariner database to identify patients who underwent one-to-two level lumbar fusion between 2020-2022. Relevant diagnoses and procedures were extracted using ICD-9, ICD-10, and CPT codes. Exclusion criteria included patients under 18 years of age, previous lumbar fusion, fusion > 2 levels, and those with surgical indications for malignancy, infection, trauma. Patients were stratified by positive COVID-19 diagnosis within 14 days of surgery, and matched 1:10 to a group of patients without COVID-19 diagnosis 90 days before or after surgery. Cohorts were matched based on age, sex, Elixhauser Comorbidity Index (ECI). Statistical analyses included student’s t-tests and chi-squared tests for continuous and categorical data, respectively. Results: Patients diagnosed with COVID-19 within 14 days of lumbar fusion demonstrated significantly increased rates of 30- (OR = 12.15, p < 0.001) and 90-day all-cause readmission (OR = 9.94, p < 0.001).These patients also exhibited higher rates of medical complications, including sepsis (OR = 3.37, p < 0.0001), deep vein thrombosis (DVT) (OR = 5.37, p < 0.0001), acute kidney injury (AKI) (OR = 4.16, p < 0.0001), acute renal failure (OR = 3.90, p < 0.0001), postoperative anemia (OR = 2.05, p < 0.0001), pneumonia (OR = 8.59, p < 0.0001), infection (OR = 2.58, p < 0.01), urinary tract infection (UTI) (OR = 2.81, p < 0.0001), and overall medical complications (OR = 3.28, p < 0.0001). Surgical complications were also more frequent, with increased rates of surgical site infections (OR = 2.24, p < 0.05) and hardware-related complications (OR = 2.23, p < 0.05). Additionally, these patients showed higher rates of 90-day (OR = 1.79, p < 0.05) and 1-year (OR = 1.64, p < 0.04) incision & drainage or debridement procedures. Discussion: This analysis shows that patients with a positive COVID-19 diagnosis within two weeks of lumbar fusion surgery face significantly higher risks of complications, readmissions, and reoperations. These findings support the suggestion of a two-week waiting period before surgery. Further research is needed to develop guidelines for managing patients with recent COVID-19 infections. Spine surgeons must carefully weigh the risks of proceeding with surgery against the risk of delaying surgery in these cases. Nan Wu 1 , Aoran Maheshati 1 , Kexin Xu 1 , Jianguo Zhang 1 , Deciphering Disorders Involving Scoliosis and COmorbidities Study Group 1 1 Peking Union Medical College, Beijing, China Background: B3GALT6-related disorders are extremely rare skeletal and connective tissue disorders. Severe early-onset spinal deformities are clinical hallmarks and usually require surgical corrections. Results: We enrolled four patients molecularly diagnosed with B3GALT6-related disorders and received spinal surgeries, and retrospectively reviewed the medical records. Patient 1 presented with severe kyphoscoliosis and segmentation defects and received a pedicle subtraction osteotomy with short fusion and dual growing rods from T3 to L3. However, coronal imbalance was observed at the 18-month follow-up.Genetic testing revealed biallelic disease-causing variants in B3GALT6. A revision surgery was successfully performed, with the level of the lowest instrumented vertebra (LIV) extended from the touched vertebra (TV, L3) to the substantially touched vertebra (STV, L4). The LIV was similarly extended to the STV in the index surgery for two subsequent patients who received pre-operative genetic testing results, and no complication has been observed. Patient 4 underwent preoperative Halo-pelvic traction to minimize complications, followed by posterior spinal fusion. The curves were successfully reduced without complications. A literature review identified (kypho)scoliosis management in 12 of the 63 patients with B3GALT6-related disorders. Limited surgical experience has been reported, with an increased rate of complications including death. Conclusions: Selecting STV as the LIV is recommended considering the joint hypermobility in patients with spinal deformities associated with B3GALT6-related disorders. Preoperative Halo-pelvic traction may also be safe and effective. Furthermore, preoperative molecular diagnosis is essential for enabling precise medicine and minimize complications. Keywords: Scoliosis; Spinal Surgery; B3GLAT6; Joint Hypermobility; Ehlers-Danlos Syndrome; Spondyloepimetaphyseal dysplasia; Genetic Testing Haley Nadone 1 , Joshua Lee 2 , Ryan Hoang 1 , Ryan Le 1 , Sohaib Hashmi 1 , Don Park 1 , Yu-po Lee 1 , Nitin Bhatia 1 , Hao-Hua Wu 1 1 University of California, Irvine, Department of Orthopaedic Surgery, Orange, United States , 2 University of Southern California, Los Angeles, United States Introduction: Extradural spine tumor surgery often presents complex challenges, with patients exhibiting a range of baseline characteristics that may influence surgical outcomes. Elevated creatinine levels, indicating impaired renal function, is a potential predictor of postoperative complications. This study explores the impact of elevated creatinine levels on surgical outcomes by comparing patients with elevated versus normal creatinine levels who underwent extradural spine tumor resection from 2013 to 2022. Understanding these differences is crucial for optimizing patient management and improving surgical strategies. Material and Methods: We queried the ACS-NSQIP database for patients who underwent extradural spine tumor surgery from 2013 to 2022. Inclusion criteria were patients over 18 years old who had undergone procedures coded under CPT codes 63275, 63276, 63277, 63278, 63290, 63300, 63301, 63302, 63303, 63308 for extradural spinal cord tumor resection. We recorded demographics, comorbidities (e.g., diabetes, smoking status, COPD), laboratory values (preoperative albumin, creatinine, white blood cells, hematocrit), and operative details (inpatient/outpatient status, anesthesia class, operation time). We assessed 30-day complication rates, including mortality, wound complications, and readmissions. Multivariable Poisson regression was used to evaluate if elevated creatinine levels were associated with complications, adjusting for demographics and comorbidities. Results: Our study included 3,089 patients with baseline creatinine levels from 2013 to 2022, of which 225 had elevated creatinine and 2,864 had normal levels. In a univariate analysis, patients with elevated creatinine were older (66.49 ± 10.95 vs. 60.11 ± 14.68 years, p < 0.001) and had a higher proportion of males (76.00% vs. 67.49%, p = 0.008) and higher BMI scores (29.04 ± 6.84 vs. 28.62 ± 6.32, p = 0.360). Those with elevated creatinine had longer hospital stays (10.25 ± 7.60 vs. 8.37 ± 7.95 days, p < 0.001) and more bleeding events requiring transfusion (37.8% vs. 19.7%, p < 0.001). Rates of wound infection were similar between groups (2.7% vs. 2.5%, p = 0.914). Poisson regression, adjusted for demographics and comorbidities, did not identify elevated creatinine as a significant predictor for mortality (χ 2 = 0.012, p-value = 0.913), bleeding events (χ 2 = 0.579, p-value = 0.447), urinary tract infection (χ 2 = 0.121, p-value = 0.728), sepsis (χ 2 = 0.262, p-value = 0.609) or operation time (χ 2 = 2.494, p-value = 0.114). Conclusion: Our findings reveal that patients with elevated creatinine levels experience longer hospital stays and higher rates of bleeding events requiring transfusion compared to those with normal creatinine levels. Although elevated creatinine is a significant predictor of length of stay and bleeding events, it does not significantly predict wound complications, cerebrospinal fluid leaks, dural tears, or neurological injuries. These insights underscore the importance of monitoring renal function in preoperative assessment and tailoring surgical strategies to mitigate risks associated with elevated creatinine levels. Haley Nadone 1 , Joshua Lee 2 , Ryan Hoang 1 , Ryan Le 1 , Sohaib Hashmi 1 , Don Park 1 , Yu-po Lee 1 , Nitin Bhatia 1 , Hao-Hua Wu 1 1 University of California, Irvine, Department of Orthopaedic Surgery, Orange, United States , 2 University of Southern California, Los Angeles, United States Introduction: Extradural spine tumor resection is a complex surgical procedure with inherent risks and complications. Previous studies have suggested that various preoperative factors, including chronic steroid use, may influence surgical outcomes. Chronic steroid use is a common treatment for various medical conditions, but its impact on surgical outcomes remains a topic of interest. In particular, the effects of chronic steroid use on patients undergoing extradural spine tumor resection have not been extensively studied. This research aims to assess the outcomes of patients on chronic steroids who undergo surgery for extradural spine tumors, focusing on postoperative complications and recovery metrics using data from the ACS-NSQIP database. Material and Methods: We analyzed ACS-NSQIP data for patients who underwent extradural spine tumor resection between 2013 and 2022, including those with relevant CPT codes (63275, 63276, 63277, 63278, 63290, 63300, 63301, 63302, 63303, 63308). Data collected included demographics, comorbidities, preoperative lab values, and operative details. We compared outcomes between patients on chronic steroids and those not using immunosuppressants. Annual 30-day complication rates were examined, and multivariable Poisson regression was used to assess whether chronic steroid use was a predictor of complications. Results: A total of 4,486 patients were analyzed, comprising 553 patients on steroids and 3,933 not using immunosuppressants. In a univariate analysis, the steroid cohort was significantly older (61.58 ± 12.66 vs 59.12 ± 14.93 years, p < 0.001) and had higher proportions of chronic obstructive pulmonary disease (6.87% vs 4.07%, p = 0.003) and hypertension requiring medication (48.1% vs 43.7%, p = 0.050). Conversely, fewer patients in the steroid cohort were smokers (13.7% vs 18.0%, p = 0.009). Notably, the steroid cohort experienced greater occurrence of pneumonia (6.5% vs 3.0%, p ≤ 0.001) and higher bleeding events requiring transfusion (26.0% vs 20.9%, p = 0.006). Wound infection rates did not differ significantly between cohorts (3.43% vs 2.95%, p = 0.531). Poisson regression revealed that steroid use was a significant predictor for pneumonia (χ2 = 5.447, p = 0.020), but not for increased deep vein thrombosis (χ2 = 0.174, p-value = 0.676) and readmission (χ2 = 0.657, p = 0.418). Conclusion: Chronic steroid use is associated with an increased risk of certain postoperative complications following extradural spine tumor resection, including increased risk of pneumonia and higher rates of bleeding events. Surgeons and patients should be aware of these risks to optimize preoperative planning and postoperative care for patients on chronic steroid therapy. Juan Castaño Montoya 1 , Rebeca Perez Alfayate 1 , Angela Carrascosa 1 1 Hospital Clínico San Carlos, Neurosurgery, Madrid, Spain Introduction: Pseudomeningocele is one of the most frequent complications after surgery for lesions in the craniocervical junction, presenting in some cases persistent symptoms and being a potential source for cerebrospinal fluid fistula with the devastating consequences associated with the development of infections in the central nervous system. Despite its high frequency, there are few reports about its management, being in some cases a surgical challenge due to its multifactorial pathogenesis. Material and Methods: This is a 28-year-old male patient who was admitted to the emergency room for progressive tetraparesis and was diagnosed through an MRI of an intradural extramedullary lesion dependent on the right C2 root with an intra and extracanal component, that compresses the spinal cord at this level and with signs of myelopathy. The patient was operated on through a posterolateral approach, achieving a complete resection and had an immediate postoperative period without incidents, being discharged in the following week after the intervention. One month after the intervention, the patient returned to the emergency room for headache that worsened with Valsalva maneuvers and bulging of the neck region. Imaging tests were performed where he was diagnosed with a tension pseudomeningocele and surgical repair was decided. Results: The surgical technique used consists of debridement of the edges of the cavity, followed by packing with fascia lata (150% larger than the maximum diameter of the cavity), placement of a subfascial drain and subsequent closure with tension sutures achieving anchoring of the fascia lata and approximation of the posterior cervical muscles. The subfascial drain is maintained for 2 weeks, achieving a decrease in the pressure exerted in the epidural space and favoring the integration of the fascia lata with the adjacent tissues and an effective closure of the surgical wound. After removal of the drain, the tension sutures are removed one by one at 48-hour intervals and the patient was discharged after removal of the last suture. A post-surgical control MRI was performed, showing a small, contained pseudomeningocele without complications. During follow-up, the patient has remained asymptomatic and has not presented any accumulation in the posterior cervical region. After one year, a new MRI was performed, showing complete resolution of the pseudomeningocele. Conclusion: Fascia lata packing and tension suturing could be a useful technique for repairing symptomatic pseudomeningoceles and refractory spinal cerebrospinal fluid fistulas secondary to large dural defects in patients undergoing surgery for craniocervical junction pathology. Rohit Bhan 1 , Salim Yakdan 1 , Jacob Greenberg 1 , Brian Neuman 1 1 Washington University in St. Louis, Orthopaedic Surgery, St. Louis, United States Introduction: Adult spinal deformity (ASD) surgery has been shown to provide substantial long-term benefit to patients, however many patients ask about short-term recovery in the 4-6 weeks after surgery. Traditional patient reported outcomes (PROs) have failed to reliably predict post-operative course, with studies showing inconsistent results. This may reflect PROs capturing a single moment in time, whereas pain, function, and activity are dynamic processes. Wearable biometric data (WBD), including motion trackers like Fitbit, provide a more comprehensive picture of physical activity. We aim to evaluate the relationship between WBD, Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function, and postoperative course after ASD surgery. Materials and Methods: ASD patients were enrolled at their preoperative visit. PROMIS scores were collected, and patients were provided a Fitbit to wear prior to surgery. Preoperatively, various activity metrics were recorded for a minimum of 1 week. Perioperative course and complications were recorded for 30 days after discharge, such as reoperation, deep vein thrombosis, dehiscence, infection, and others. Parametric and non-parametric analyses were performed to assess significance. Results: A total of 23 ASD patients were enrolled. Average fusions levels were 10.4 (SD = 3.6), all patients were fused to pelvis. All-posterior surgery was received by 8 patients and 15 received anterior-posterior surgery. Perioperative complications were experienced by 8 patients (35%) and 3 (13%) patients were readmitted within 30-days of discharge. Patients with greater activity measured by WBD were less likely to experience complications. Between complication and non-complication groups, number of steps per activity bout was 44.5 and 81.0 (p = 0.017), active time per bout was 1.78 and 2.59 (p = 0.028), and number of steps per minute of activity was 23.5 and 29.1 (p = 0.028) respectively. No difference was found for PROMIS Physical Function between complication groups (p = 0.104). Conclusion: Increased preoperative activity determined by WBD was associated with decreased complications, however no relationship was found with self-reported activity questionnaires. These preliminary findings suggest that WBD is superior to traditional PROs in assessing activity levels and may have utility in predicting perioperative course. Rohit Bhan 1 , Vy Pham 1 , Elizabeth Yanik 1 , Brian Neuman 1 1 Washington University in St. Louis, Orthopaedic Surgery, St. Louis, United States Introduction: The prevalence of symptomatic spinal disease requiring fusion is increasing with an aging population. Patients are counseled there is a 3% annual risk of additional surgery due to adjacent segment disease (AdSD), though this may not account for advances in surgical technique. The UK BioBank (UKB) is a large population-based cohort of 500,000 deidentified people, with in-depth genetic and non-genetic information, as well as linked hospital records. The database is regularly updated and includes >20 years of hospital records. We aim to investigate the rate of AdSD after primary cervical and lumbar fusion in the UKB cohort, as well as risk factors that may contribute. Materials and Methods: UKB patients that underwent primary lumbar or cervical fusion, as well as anterior cervical fusion (ACF) or posterior cervical spine fusion (PCF) were identified using OPCS-4 codes. AdSD was the endpoint, defined as subsequent fusion, revision, or decompression within the same spine. Risk factors were assessed using multivariable Cox regression analysis. Cumulative incidence was calculated to estimate the annualized risk of AdSD. GWAS analysis was performed to identify small nucleotide polymorphisms (SNPs) associated with AdSD. Results: 3487 patients underwent primary fusion in the cervical (N = 1732, ACF = 1571, PCF = 121, combined = 42) or lumbar (N = 1755) spine. 211 (12.1%) cervical and 230 (13.1%) lumbar patients were revised for AdSD. 5-year AdSD rate was 8.33% (cervical) and 10.24% (lumbar), and at 20-years was 20% (cervical) and 19.84% (lumbar), amounting to an annual risk of ∼1%. Unemployed/Retired status achieved significance as a risk factor for all AdSD patients (p = 0.0063). GWAS analysis for all AdSD patients identified a novel SNP (rs116459848, Chromosome 5). Previously reported SNPs associated with degenerative pathologies (spondylolisthesis, disc disease, spinal stenosis) failed to achieve significance. Conclusion: The combined risk of AdSD for lumbar and cervical spine fusion is lower than previously reported, 1% annually with about 40% of cases occurring within the first 5 years and the remainder of cases occurring in the following 15 years. There may be risk factors accounting for the increased early rate of AdSD, including surgical factors and patient factors. We identified a novel SNP that associated with AdSD cases in the absence of SNPs associated with degenerative pathologies. This suggests there may be a novel genetic component to AdSD, and AdSD may represent a separate disease. Bahri Farah 1 , Ghassen Gader 1 , Abdelhafidh Slimane 2 , Wièm Mansour 1 , Hdhili Houssem 1 , Aziz Bedioui 1 , Mohamed Zouaghi 1 , Mouna Rkhami 1 , Mohamed Badri 1 , Kamel Bahri 1 , Zammel Ihsen 1 1 Trauma and Burns Center, Department of Neurosurgery, Ben Arous, Tunisia , 2 National Institut of Neurology, Department of Neurosurgery, Tunis, Tunisia Introduction: Pneumocephalus, defined as the presence of air within the skull, is an unusual complication typically linked to head trauma or surgeries that disrupt the continuity of the skull and its meninges. Although rare, it can occur following spinal surgeries, particularly in the context of iatrogenic dural tears. The condition often presents with non-specific symptoms, which can mislead diagnosis and delay proper management. Materials and Methods: We present two cases of symptomatic pneumocephalus after spinal surgery. The first case refers to a 70-year-old woman who underwent an anterior cervical discectomy and fusion for a herniated C5-C6 disc. The second case involved a 40-year-old woman who underwent lumbar discectomy for a herniated L4-L5 disc. In both cases, there was an iatrogenic dural tear, resulting in Cerebrospinal fluid leakage. Due to the lateral location of the breach, it was not possible to suture the tear and no biological glue or sealant were used. Within 24 hours of surgery, both patients developed headaches and seizures, with pneumocephalus diagnosed by emergency brain CT scans. Both cases were treated conservatively. Full clinical assessments, imaging findings and treatment protocols were reviewed to unravel the presentation and outcomes of pneumocephalus in these surgical settings. Results: Pneumocephalus often presents with non-specific symptoms, such as headache and altered consciousness. In our cases, the primary symptoms were headaches and seizures, with seizures being a less common but more severe manifestation of the condition. Accidental breaches of the dura mater during spinal surgery can lead to cerebrospinal fluid (CSF) leakage and the entry of air into the cranial cavity. This air can exert pressure on brain tissue, potentially resulting in tension pneumocephalus, which may cause severe neurological outcomes such as seizures, and, if untreated, brainstem herniation. Additionally, the decrease in intracranial pressure from CSF leakage can exacerbate symptoms and lead to further complications. Management of symptomatic pneumocephalus generally involves conservative measures. In our cases, this included monitoring and symptomatic treatment. Techniques such as positioning and overhydration can help reduce intracranial pressure and promote air resorption. Other strategies, such as hyperbaric oxygen therapy and overhydration, might be considered, though their effectiveness can vary. Our cases demonstrate that conservative management can be effective, with both patients showing resolution of symptoms and no further complications at follow-up. Preventing pneumocephalus involves avoiding breaches of the dura mater. If Such breaches occur, immediate and systematic repair is essential to minimize complications. Conclusion: Symptomatic pneumocephalus, while rare following spinal surgery, presents a critical challenge in postoperative management. Our cases demonstrate that early recognition through imaging and prompt conservative management are essential for recovery. Prevention through careful surgical technique and immediate repair of dural breaches is essential to reduce the risk of this complication. Hdhili Houssem 1 , Ghassen Gader 1 , Bouzouita Kais 2 , Bahri Farah 1 , Wièm Mansour 1 , Aziz Bedioui 1 , Mohamed Zouaghi 1 , Mouna Rkhami 1 , Mohamed Badri 1 , Kamel Bahri 1 , Zammel Ihsen 1 1 Trauma and Burns Center of Ben Arous, Department of Neurosurgery, Ben Arous, Tunisia , 2 National Institute of Neurology of Tunis Mongi Ben Hamida, Department of Neurosurgery, Tunis, Tunisia Introduction: Interlaminar discectomy in lumbar disc herniation surgery is considered a minimally invasive procedure. It is commonly practiced today despite the advent of new so-called minimally invasive techniques. However, this surgery is not without complications. Epidural fibrosis (EF) is a major cause of failure due to the recurrence of disabling radiculopathies. Despite the variety of therapeutic modalities, the strategy remains debated. Material and Methods: We went through a retrospective descriptive study concerning 42 cases of postoperative epidural fibrosis among 369 patients operated on for lumbar disc herniation via the intralaminar approach in the neurosurgical department of the trauma and burns center of Ben Arous during the period ranging between January 2021 and December 2023. Results: The prevalence of symptomatic disc herniation was 11.38%, with an average age of 40.5 years. The male-to-female ratio was 2.23. The onset of symptoms occurred within the first six months in 76.19% of cases. Clinical examination revealed a positive Lasègue sign in 30.95% of cases, hypoesthesia in 73.8%, and no motor deficits or genitourinary-sphincter disorders. All patients underwent lumbar magnetic resonance imaging (MRI). The most affected disc spaces were L4-L5 (59.52%) and L5-S1 (38.09%), which were the sites of the surgeries. The radiological grade was significant (between 3 and 4) in 66.66% of cases. All patients received medical treatment including pregabalin, gabapentin, and amitriptyline. 14% were reoperated with poor outcomes, experiencing a recurrence of symptoms after 3 months. The confirmed risk factors included diabetes, with a prevalence of 50% among patients with disc herniation compared to 15.6% in the general population. Tobacco use was also a risk factor, with a prevalence of 69.24%. The average blood loss was 139.28 ml in patients with disc herniation compared to 87.61 ml in others. The average duration of surgery was 104.28 minutes compared to 50.27 minutes. Clinical outcomes were good in 35% of patients, with a significant correlation found with the radiological grade. Conclusion: Postoperative epidural fibrosis is a disabling condition. It presents a therapeutic challenge due to its impact on morbidity and socioeconomic costs. However, prevention remains a crucial aspect by addressing risk factors. The interlaminar approach remains a minimally invasive technique with a relatively low incidence of epidural fibrosis. Joydeep Baidya 1 , Jonathan Dalton 1 , Rajkishen Narayanan 1 , Rachel Huang 1 , Chloe Herczeg 1 , Robert Oris 1 , Jarod Olson 1 , Michael Carter 1 , Nicholas Pohl 1 , Matthew Sabitsky 1 , Sebastian Fras 1 , Shane Kozick 1 , Jose Canseco 1 , Alan Hilibrand 1 , Alex Vaccaro 1 , Gregory Schroeder 1 , Chris Kepler 1 1 Rothman Orthopaedic Institute, Philadelphia, United States Introduction: Ankylosing spondylitis (AS) is the most common form of spondyloarthritis and usually manifests in inflammatory back pain and excess bone formation in the spine. Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory condition that is characterized by contiguous ossification of 4 or more vertebral bodies and can present similarly to AS. The goal of this study is to address a gap in the literature regarding surgical and patient-reported outcomes after elective cervical and lumbar surgery amongst patients with these conditions. Material and Methods: Adult patients with AS or DISH undergoing elective spine surgery at a tertiary care center were retrospectively identified (2004-2023) using ICD-9/10 codes and keyword searches. Exclusion criteria—trauma indication, and combined anterior-posterior approaches. Patients were 3:1 propensity score matched to a control cohort of patients without AS/DISH undergoing similar procedures. Demographic and surgical variables were collected. Outcomes included discharge disposition, 0-30 and 31-90 day readmission rates, 1-year revisions and reoperations, and patient-reported outcome measures (PROMs). Results: 66 patients with AS/DISH met inclusion criteria - 42 underwent cervical surgery (25 ACDF, 17 PCDF) and 24 underwent lumbar surgery (17 PLDF, 7 TLIF). In the cervical cohort, CCI was greater in the AS/DISH group (3.02 ± 1.65 vs. 1.92 ± 2.07, p < 0.001). Patients with AS/DISH experienced higher rates of 0-30 day readmission in both cohorts (Cervical: 9.52% vs. 1.59%, p = 0.035; Lumbar: 20.8% vs. 2.78%, p = 0.010). In the cervical cohort, AS/DISH patients experienced higher rates of 31-90 day readmission (7.14% vs. 0.79%, p = 0.049) while in the lumbar cohort, a greater proportion of them were discharged to skilled nursing facilities (19.0% vs. 4.55%, p = 0.002). Patients in neither cohort experienced any differences in 1-year reoperation or revision. In the cervical cohort, 1-year VAS Neck and VAS Arm; 2-year VAS Arm; 3-month, 1-year, and 2-year mJOA; and 1-year and 2-year MCS were better for AS/DISH. In the lumbar cohort, delta 6-month VAS Back was better while preoperative and 6-month VAS Back; delta 6-month and 1-year VAS Leg; and delta 6-month and 2-year MCS were worse for AS/DISH patients (all p < 0.05). Conclusion: AS/DISH is associated with short-term readmissions after elective cervical and lumbar surgeries. Although there were differences in several postoperative PROMs between AS/DISH and control patients, the change from baseline was generally similar. Surgeons should attempt to avoid readmissions and optimize outcomes for AS/DISH patients via early postoperative mobilization, pain expectation counseling and proactive multimodal pain control, and proper DMARD management to minimize infection complications. However, these results indicate that patients with AS/DISH can safely undergo elective spine surgery without significant additional burden of postoperative complications. Devender Singh 1 , Eeric Truumees 1 , Morgan Laviolette 1 , Qais Zai 1 , Vik Kohli 1 , Matthew Geck 1 , John Stokes 1 , Rory Mayer 1 1 Ascension, Austin, United States Introduction: Hematogenous spinal osteomyelitis poses significant risks of morbidity and mortality. The clinical presentation and outcomes of these patients vary based on factors such as age, comorbidities, spinal region involvement, and antibiotic use. Effective risk stratification could allow for improved treatment protocols and better clinical outcomes by identifying high-risk patients. The aim of this study was to analyze the clinical characteristics and outcomes of patients with hematogenous spinal osteomyelitis and develop a multivariate risk score to predict adverse outcomes, specifically sequelae. Additionally, the study sought to determine the impact of long-term antibiotic use, age, BMI, comorbidities, and spinal area on patient outcomes. We hypothesized that age, BMI, comorbidities, spinal area involvement, and pre-antibiotic use would be significant predictors of adverse clinical outcomes in hematogenous spinal osteomyelitis. Furthermore, it was hypothesized that a multivariate risk score could effectively stratify patients into high- and low-risk groups for sequelae. Material and Methods: Outcomes measured were sequelae, reoperation, length of stay (LOS), and mortality. Descriptive statistics and multivariate logistic regression were employed to identify significant predictors of sequelae, and a risk score was developed based on the model coefficients. Risk score thresholds were optimized to balance sensitivity and specificity for predicting sequelae. Results: The analysis included 98 patients, with a median age of 65 years and a majority of patients were male. Patients presented with a wide range of BMIs, from underweight to severely obese. Comorbidities such as diabetes and cardiovascular disease were prevalent. Age, comorbidities, and pre-antibiotic use were found to be significant predictors of sequelae. Older patients had a higher likelihood of developing sequelae (coefficient: 0.1348), while higher BMI was associated with a slight protective effect (coefficient: -0.0723). The presence of comorbidities significantly increased the risk of sequelae (coefficient: 0.2976), and patients who received antibiotics prior to admission were at increased risk (coefficient: 0.5554), likely reflecting the severity of their condition. The multivariate risk score demonstrated strong predictive ability, and a threshold of 0.4 provided an optimal balance between sensitivity (65%) and specificity (85%). Patients classified as high-risk were more likely to develop sequelae, while those in the low-risk category had fewer complications. Long-term antibiotic use was associated with a slight reduction in mortality, from 8.7% to 4.4%, but did not significantly impact sequelae rates. Conclusion: This study highlights the critical role of age, comorbidities, and pre-antibiotic use in determining outcomes for patients with hematogenous spinal osteomyelitis. The multivariate risk score developed provides a valuable tool for clinicians to stratify patients by risk and tailor their treatment approaches accordingly. Targeted management of high-risk patients, especially those with comorbidities and advanced age, along with early antibiotic intervention, may improve clinical outcomes. The slight reduction in mortality with long-term antibiotic use suggests a potential survival benefit for extended antibiotic therapy, but further research is required to understand the optimal duration and impact on long-term complications. Further research should focus on prospective validation of this risk score and its integration into clinical decision-making. Tiffany Lung 1 , Shikha Duggal 1 , Norah Matthies 1 , Chloe Cadieux 1 , Jed Lazarus 1 , Christopher J. Nielsen 1 , Raja Rampersaud 1 1 University Health Network, Toronto Western Hospital, Toronto, Canada Introduction: There is a plethora of literature supporting higher rates of risk of surgical site infections (SSI) in patients with diabetes. In spine surgery patients, diabetes has been shown to be an independent risk factor for SSI and all-cause complications. Despite this, preoperative Hemoglobin A1c (HbA1c) and/or postoperative glucose checks are not routinely performed at our institution. Material and Methods: This is a prospective pilot study evaluating patients who had inpatient elective spine surgery in 2022 from a single surgeon at a single institution, and a HbA1c measurement within 90 days of surgery. The primary outcomes of interest are the number of patients with unknown diabetes or prediabetes, or elevated perioperative glucose. Secondary outcomes of interest include length of stay, reoperation rates, rates of SSI, all-cause complications, readmission rates, discharge rates to home, post-operative visit to ED, and mortality rates. Results: One hundred and four patients had a preoperative HbA1c measured within 90 days of surgery. Of these patients, we did not identify any patients with unknown diabetes, however, there were four patients with unknown pre-diabetes. Furthermore, only 33 patients had their blood glucose measured on postoperative day 0, 1, or 2. Thirteen patients had hyperglycemia postoperatively and they all were either pre-diabetic or diabetic. No patients with a HbA1c less than 6 had hyperglycemia post operatively. Conclusion: In our study, we found 4 patients with unknown prediabetes, and elevated blood glucose levels only in patients with prediabetes or diabetes. In the future, HbA1c should be ordered routinely to identify patients who would have abnormal glucose regulation which would put them at higher risk of SSI and surgical complications. Prerana Katiyar 1 , Zeeshan Sardar 2 , Caroline Taber 2 , Grant Feuer 2 , Justin Reyes 2 , Matan Malka 2 , Fthimnir Hassan 2 , Prakash Gorroochurn 2 , Lawrence Lenke 2 1 Hospital for Special Surgery, New York, United States , 2 Columbia University Medical Center, New York, United States Introduction: Complex spinal deformity surgeries are notable for their risk of major blood loss. Traditionally, blood loss is compensated with allogenic blood transfusions, such as packed red blood cells (RBCs). However, allogenic blood transfusions carry their own risks and complications. Instead, cell saver (CS) uses each patient’s own RBCs to re-administer blood intraoperatively. While many studies have demonstrated the efficacy and cost effectiveness of CS in adult spinal deformity (ASD) surgery, some studies have failed to replicate this. Recent literature has noted that high CS volumes (> 550 mL) may be correlated with early postoperative medical complications. Given the conflicting role of CS in ASD surgery, the aim of this study was to investigate if high CS volumes (CS > 550 mL) are associated with cardiopulmonary complications in the early postop period (i.e. 90 days). Methods: 228 ASD patients who underwent surgery at a single center from 2015-2021 with > 1.5L EBL and > 4 levels of fusion who received CS were identified. 7 patients had no documented volume of and were excluded from analysis. Ages ranged from 18-77 yrs at surgery. 2 groups were stratified: high CS group (CS > 550 mL) and low CS group (CS ≤ 550 mL). Demographics, intraoperative transfusion data, postoperative transfusion data, 90-day readmission/reoperation rates, and cardiopulmonary complications such as anemia, thrombocytopenia, hypotension, venous thromboembolism (VTE), pulmonary edema (PE)/vascular congestion/acute respiratory distress syndrome (ARDS), and atelectasis/pneumothorax were collected. Multi-logistic regression was utilized to identify relationships between intraoperative CS and 90-day postop cardiopulmonary complications, and readmissions/reoperations. SPSS 28.0.0.0. was utilized to conduct all analysis). Results: The average age at surgery was 51.9 yrs, 154 pts were female (68%) and 74 were male (32%). 151 pts were in the high CS group (66%) and 77 pts were in the low CS group (34%). Out of 228 ASD pts, 65/228 (28.5%) had anemia, 19/228 (8%) had thrombocytopenia, 74/228 (32%) had hypotension, 9/228 (4%) had VTE, 44/228 (19.2%) had PE/vascular congestion/ARDS, and 30/228 (13%) had atelectasis/pneumothorax (13%) at 90-day postop status. Additionally, 34/228 (15%) had a reoperation while 41/228 (18%) of pts were readmitted. Age at surgery, total instrumented levels (TIL), packed RBCs transfused, and EBL were adjusted for. Multi-logistic regression showed that CS > 550 mL transfused during surgery was not significant for anemia (p = .529), thrombocytopenia (p = .609), VTE (p = .290), PE/vascular congestion/ARDS (p = .323), atelectasis/pneumothorax (p = .211), 90 day readmissions (p = .099), 90 day reoperations (p = .315). However, interestingly, CS > 550 mL was associated with hypotension (p = .005, 95% CI = [1.367, 6.137]). Conclusions: High CS volumes administered during ASD surgeries are not positively correlated with most cardiopulmonary complications. However, CS volumes > 550 mL may induce hypotension in the early postop phase in pts undergoing ASD correction. Further studies are needed to investigate the relationship between CS volume and postop medical complications. Emily Tse 1 , Yijie Luo 1 , Amalvin Fritz 1 , Ryan Hoang 1 , Ryan Le 1 , Joshua Lee 1 , Noah Ross 1 , Joe Morrissey 1 , Haley Nadone 1 , Don Park 1 , Sohaib Hashmi 1 , Hao-Hua Wu 1 , Nitin Bhatia 1 , Yu-po Lee 1 1 University of California, School of Medicine, Irvine, United States Introduction: Anterior cervical discectomy and fusion (ACDF) is a common surgical procedure used to treat cervical radiculopathy or myelopathy. In the past decade, ACDF utilization has increased significantly as a result of high patient reported success rates along with low rates of pseudoarthrosis and adjacent segment disease. The growing popularity of ACDF, driven by its favorable outcomes, highlights the need for further investigation into postoperative outcomes and risk factors of ACDF. Previous literature, which investigated trends in ACDF outcomes from 2006 to 2016, determined risk factors for unfavorable postoperative outcomes and increased rates of readmission without significant changes in other outcomes. However, after 2016 there is a lack of literature on the trends in the post-operative outcomes of ACDF procedures from 2012 to 2022. Material and Methods: Patients ≥ 18 years old undergoing ACDF between 2012-2022 were identified using the ACS-NSQIP database with CPT code 22551. Patient comorbidities including diabetes, smoking, COPD, heart failure, hypertension, and steroid use were studied. Clinical outcomes were also reported including wound infection, readmission, reoperation, length-of-stay, intraoperative blood transfusions, and mortality. ANOVA was performed to compare comorbidities and complication rates between years. Results: Changes in rates of wound infection, urinary tract infection, deep vein thrombosis, reoperation, and mortality between 2012 and 2022 were non-significant. Rates of pneumonia increased from 0.62% in 2012 to 0.79% in 2022 (p = 0.015). The occurrence of sepsis remained at 0.28% in 2012 and 0.28% in 2022 with a minor increase to 0.49% in 2020 (p = 0.05). Readmission rates increased from 2.89% in 2012 to 3.25% in 2022 (p < 0.001). The average length of stay decreased from 1.94 days in 2012 to 1.76 days in 2022 (p < 0.001). Conclusion: From 2012 to 2022, rates of diabetes, smoking, COPD, heart failure, hypertension, and steroid use among ACDF patients significantly increased. Despite increasing medical complexity, the rate of most complications remained constant. Readmission rates and pneumonia increased gradually from 2012 to 2022 with the average length of stay decreasing gradually. The rate of pneumonia peaked at 1.1 % in 2020 with readmission rates peaking in 2021 at 3.61%. These findings are valuable in identifying outcomes where quality improvement has been successful and others where further improvement is needed. Aiyana Williams 1 , Joshua Lee 1 , Eisa Razzak 1 , Noah Ross 1 , Joe Morrissey 1 , Ashish Ramesh 1 , Amalvin Fritz 1 , Haley Nadone 1 , Charlotte Yuan 1 , Yu-po Lee 1 , Nitin Bhatia 1 1 University of California Irvine, School of Medicine, Irvine, United States Introduction: Posterior cervical fusion (PCF) is a surgical technique performed in the back of the neck to join two or more damaged cervical vertebrae using a bone graft that fuses the vertebrae over time. Posterior cervical laminectomy (PCL) is a surgical procedure aimed at alleviating pressure from the spinal cord and surrounding nerves in the back of the neck. There is a lack of studies in the literature examining certain risk factors and their corresponding effects on postoperative outcomes in both single and multilevel PCF and PCL procedures. Material and Methods: National Surgical Quality Improvement Program (NSQIP) patient cases from 2012 to 2022 were included and adult patients undergoing PCF between 2006 and 2022 were identified. Poisson regression models were used to analyze correlation between comorbidities and outcomes from 2012 to 2022. Results: A total of 30,572 patients undergoing surgical procedures PCF and PCL between 2012-2022 were included. The mean age among the study population was 63.08 ± 12.46 years and the mean body mass index (BMI) was 30.69 ± 6.91 kg/m2. Age significantly impacted rates of pneumonia, uterine tract infections (UTIs), blood transfusions, deep vein thrombosis (DVT), readmission, and length of stay (LOS). Over the study period, BMI and diabetes increased from an average of 29.41 to 30.33 (p ≤ 0.001) and 19.03% (p = 0.037) respectively. There is a casual link between BMI and wound infection (p < 0.001), UTIs (p = 0.033), reoperation (p ≤ 0.001), readmission (p = 0.001), and LOS (p ≤ 0.001). Diabetes appears to have a direct correlation to wound infection (p = 0.002), UTIs (p = 0.018), sepsis (p < 0.001), reoperation (p = 0.007), readmission (p < 0.001), and LOS (p < 0.001). Additionally, heart failure appears to have a link to wound infection (p = 0.006), pneumonia (p < 0.001), UTIs (p = 0.007), blood transfusions (p = 0.021), reoperation (p = 0.014), readmission (p < 0.001) and LOS (p < 0.001). Finally, steroid use appears to be directly correlated to several comorbidities, including wound infection, pneumonia, UTI, blood transfusion, sepsis, reoperation, readmission, and LOS, each with p < 0.001 respectively. Conclusion: Multilevel instrumentation leads to higher complication rates and longer recovery periods, especially for older patients as well as patients with a large BMI, diabetes, heart failure, and steroid use. Further study with targeted strategies may provide further insight on treatments to mitigate these risk factors. Additionally, lifestyle changes, minimally invasive techniques and structured therapy programs may reduce postoperative complications. Kamrul Ahsan 1 1 Bangladesh Sheikh Mujib Medical University (BSMMU), Orthopaedic Surgery, Dhaka, Bangladesh Introduction: Discitis is a rare but dreaded complication following discectomy. To perform retrospective analysis of 75 post-operative disc space infections after open lumbar discectomy (OLD) and to assess the outcome of their medical and surgical management in a tertiary-level hospital. Material and Methods: Records of 50 men and 25 women aged 26-65 (mean, 42.53) years who underwent treatment for post-operative discitis (POD) after single level OLD at L3-4 (n = 8), L4-5 (n = 42), L5-S1 (n = 25) level. The POD was diagnosed according to specific clinical signs, laboratory and radiographic investigations and all of them received initial intravenous antibiotics (IVA) for at least 4-6 weeks followed by oral ones. Successful responders (n = 55) were considered in Group-C and remainder [Group-S (n = 20)] were operated at least after 4 weeks of failure. Demographic data, clinical variables, hospital stay, duration of antibiotic treatment and post-treatment complications were collected from the hospital record and assessment before and after treatment were done by using visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score. Comprehensive outcome was evaluated by modified criteria of Kirkaldy-Willis. Results: The mean follows up was 36.38 months. Significant improvement of mean VAS and JOA score was achieved in both conservative (76.36% satisfactory) and operative (90% satisfactory) groups although the difference was statistically insignificant. Conclusion: Although insignificant, early surgical intervention provided better results (e.g., functional outcomes, length of hospital stay and duration of antibiotic treatment therapy) than conventional conservative treatment in post-operative discitis. Ahmed Hassan 1,2 , Mohamed Hassanien 1,2 , Ahmed Shawky Abdelgawaad 2,3 1 Queen`s Medical Centre, Nottingham University Hospitals NHS Trust, Centre for Spinal Studies and Surgery, Nottingham, United Kingdom , 2 Assiut University School of Medicine, Department of Orthopedics and Trauma Surgery, Assiut, Egypt , 3 Helios Klinikum Erfurt, Erfurt, Germany Introduction: Incidental durotomy is a very common complication in spine surgery, with an incidence ranging between 1 and 17%. However, the vast majority of those cases are identified and managed intraoperatively with various techniques of dural repair. Rarely, some dural tears can go unrecognized and present with symptoms of cerebrospinal fluid (CSF) leakage, ranging from headache to wound discharge, many days after the surgery. Those late presenting dural tears (LPDT) are considered much more challenging in their management as they are associated with increased postoperative morbidity and an increase in surgeon malpractice liability. The main aim of our study was to assess all the available literature on LPDT, trying to shed more light on their risk factors and different management options. Material and Methods: A systematic review of the English-language literature was conducted using PubMed, Web of Science, and Cochrane databases up to September 2024, adhering to the PRISMA guidelines using free text forms and Boolean operators. All Study designs, except review articles, were included in our study. Studies, where a dural tear was identified in the index surgery or studies without adequate intra-operative details of the index procedure, were excluded. The Risk of Bias (ROB) was assessed using the Joanna Briggs Institute (JBI) tool. Results: Out of the 960 articles that were initially identified, only 25 articles were assessed for eligibility. A total number of 13 articles were finally included in the study. The main reasons for exclusion were the identification of a dural tear in the primary surgery (5 articles) followed by the lack of adequate information from the primary surgery confirming the absence of a dural tear (4 articles). 11 articles were either case series or case reports (level IV) and only two articles were retrospective cohort studies (Level III). Meta-analysis could be performed due to the limited number of comparative studies. Across all studies, 217 patients developed a late presenting dural tear, with a slight male predominance (118 male vs. 99 female). Their age ranged from 15 to 84 years. The main presenting symptom was headache (94%), followed by wound discharge (4.6 %), with only three patients complaining of radicular pain (1.4%). CT myelography was the imaging modality of choice in most cases. Most surgeries involved the thoracolumbar spine (197 cases), with only twenty cervical spine cases. The mainstay of treatment was surgical re-exploration and dural repair, if possible, with the removal of any identified bone spicules or mal-positioned implants. Conservative management was successful in only 5 cases (2.3%). Three cases (1.4%) were managed by an epidural blood patch, and 2 cases (0.9%) with an external ventricular drain. Conclusion: Despite being a rare complication, LPDT remains challenging to diagnose and manage. Based on our study, we recommend using CT myelography as the diagnostic modality of choice in cases presenting with symptoms of CSF leakage after spinal surgery. After establishing the diagnosis, early surgery with exploration and dural tear repair provides better outcomes compared to conservative treatment or other treatment modalities such as epidural blood patches. Michal Krakowiak 1 , Jarosław Dzierżanowski 1 , Klaudia Kokot 2 , Rami Yuser 2 , Piotr Zieliński 1 1 Medical University of Gdansk, Neurosurgery, Gdansk, Poland , 2 Medical University of Gdansk, Students’ Scientific Circle of Neurosurgery, Gdansk, Poland Introduction: Cerebrospinal fluid leaks (CSFL) as complications after spine surgeries are a wide problem. The occurrence ranges between 2-20% and often requires surgical intervention. The aim of this study is to investigate the economic burden of CSFL readmissions. Material and Methods: The study includes a retrospective analysis of postoperative CSFL patients who were emergently admitted to the Department of Neurosurgery at the University Clinical Center in Gdansk from 01.2020 up to 07.2024 and treated surgically. Data was gathered on the basis of ICD 10 classification and ICD9 procedure list. Economic data was provided by SGA company by the website MyHospital. Results: 25 patients were included into the analysis. The mean age of patient was 53 years. The mean hospital stay was 9 days. The mean hospitalization cost was 19877 PLN. 16 cases (64%) generated loss to the Department. The mean financial result of hospitalization was -6042.68 PLN. Age was an statistically insignificant factor when compared patients generating loss and not for the Department. Conclusion: The results of this economic analysis show that the economic burden due to readmission of CSFL is great. Prevention measures should be undertaken to reduce the economic burden caused by readmissions. Jacequeline Tobin 1 , John Martin 1 , Mark Kouame 1 , Gabriella Rivas 1 , Charles Reitman 1 , John Glaser 1 , James Lawrence 1 , Robert Ravinsky 1 1 Medical University of South Carolina, Charleston, United States Introduction: Anterior cervical discectomy and fusion (ACDF) is considered an effective, low risk treatment for a wide variety of pathologies of the cervical spine. The position of the hyoid pre-operatively, in relation to the cervical spine, is considered a possible risk factor for the development of dysphagia following ACDF. Previous studies have demonstrated that the hyoid position can vary significantly in relation to the cervical spine and have shown that surface landmarks – such as the hyoid bone – are not reliable markers to guide an anterior approach to the cervical spine. Pre-operative knowledge of the hyoid position and its exact anatomical relation to the cervical spine could affect the risk of dysphagia post-operatively. As such, this study is designed to investigate the correlation between hyoid position and ACDF post-operative complications, specifically, dysphagia. Methods: Retrospective review of patients undergoing ACDF at a single, tertiary-care institution, during a 10-year period. Cases were excluded if the patient had undergone previous cervical spine surgery, if ACDF was performed due to trauma, any levels outside of C2/3 and C3/4 and C2-4, and any three-level fusions. Data were collected on patient demographics, surgical characteristics, radiographic determination of the hyoid level via k-line measurement of pre-operative films, and 30-day complication rates. Results: A total of 43 patients were included, with a 1.4:1 male to female ratio and an average age of 61.12 ± 15.98 years. The hyoid bone was commonly measured at the level of the C3 vertebral body (33%), C4/5 disc (26%), and C4 vertebral body (19%). The rate of dysphagia status-post ACDF in this cohort was 14% (6/43), with 50% (3/6) of these patients requiring referral to speech-language pathologists. Rate of 30-day readmission and mortality was 5% and 0%, respectively. 4/6 patients who experienced dysphagia had a hyoid body measured at the level of the C3 body. The other two patients had hyoid bodies measured at the level of the C4 vertebral body and C4/5 disc. Discussion: Preliminary data demonstrates a trend towards increased rate of dysphagia in patients with higher measured hyoid bones, at the level of the C3 body. Further research is required to better ascertain the relationship between the hyoid position in relation to the cervical spine and the rate of dysphagia in patients undergoing elective ACDF. Alexandro Duenki 1 , Adrian Kohler 1 , Hagen Bomberg 1 , Mazda Farshad 2 , Urs Eichenberger 1 , Sathish Muthu 3 4 5 , Andreas Demetriades 6 , S. Tim Yoon 7 1 Balgrist University Hospital, Department of Anaesthesiology, Intensive Care Medicine and Pain Medicine, Zurich, Switzerland , 2 Balgrist University Hospital, University Spine Centre, Zurich, Switzerland , 3 Government Medical College, Department of Orthopaedics, Karur, India , 4 Karpagam Academy of Higher Education, Department of Biotechnology, Coimbatore, India , 5 Orthopaedic Research Group, Department of Spine Surgery, Coimbatore, India , 6 Royal Infirmary Hospital, Department of Clinical Neurosciences, Edinburgh, United Kingdom , 7 Emory University, Department of Orthopaedics, Atlanta, United States Introduction: Thromboprophylaxis after thoraco-lumbar spine surgery has been controversially discussed for decades. Clear evidence-based guidelines for the best prophylaxis modality are still missing. In this international survey, we queried the spine surgeons on their postoperative thromboprophylactic practices to know the current practice preferences and its outcomes. Methods: The survey was distributed electronically to all members of the AO Spine Foundation worldwide. A total of 240 respondents were recorded between June 26, 2024 and July 10, 2024. The survey consisted of 27 questions of which 14 were analyzed in this study (12 questions addressed general information and 2 addressed the way in which thromboprophylaxis were performed in patients without or with heightened risk of venous thromboembolism with the use of either compression stockings, intermittent pneumatic compression devices, low molecular weight heparin or other methods). We defined consensus for binary (yes/no) question at > 80% or < 20%, intermediate consensus between 60-80% or 20-40% and between 40-60% were designated controversial. Results: The practice regions of the 240 respondents were Asia Pacific (21%), Europe and Southern Africa (33%), Latin America (20%), Middle East and Northern Africa (15%), and North America (11%). The way in which thromboprophylaxis was carried out remained controversial in patients without heightened risk of venous thromboembolism. In contrast, in patients with an increased risk of venous thromboembolism, an intermediate consensus of 75% was found for low molecular weight heparin only. However, low molecular heparin and pneumatic compression devices are the preferred methods in high risk patients in Europe and North America respectively. Conclusion: Our results show that the way in which thrombosis prophylaxis is currently carried out remains controversial and varies in the different practice regions. There is a need for a practice guidelines on this regard to standardize the thromboprophylactic practice to ensure the best possible benefits avoiding the unnecessary harms to the patients undergoing spine surgery.

Roman Khalepa 1,2 , Yuliy Kubeckiy 1 , Evgeniya Amelina 3 1 Federal Center of Neurosurgery, Spinal Neurosurgical Department, Novosibirsk, Russian Federation , 2 Novosibirsk State Medical University, Department of Neurosurgery, Novosibirsk, Russian Federation , 3 Novosibirsk State University, Center for Technology Transfer and Commercialization, Novosibirsk, Russian Federation Introduction: Lumbar spinal stenosis is the most common cause of spinal surgery in elderly patients. Current surgical option for lumbar spinal stenosis is microsurgical bilateral “Over the top” decompression. At the present intralaminar full endoscopic bilateral decompression for spinal stenosis is a safe surgical procedure but it’s effectiveness is still being discussed. The goal of this study is to compare the results of full endoscopic decompression with those of the standard microsurgical technique in patients with degenerative lumbar spinal stenosis. Material and Methods: 99 patients aged 51 to 88 with symptomatic spinal stenosis underwent bilateral over the top microsurgical decompression (n = 48) and full endoscopic decompression (n = 51). Standard scales and questionnaires were used to objectify symptoms of the disease before and after surgery: walking distance in meters, back and leg pain (VAS), Oswestry Disability Index (ODI). MRI used to determine the cross-sectional area of the dural sac before and after surgery. Clinical outcome defined during 12 months after surgery. Clinical efficacy was assessed according to the MCID (Minimal Clinical Important Difference). Results: Blood loss in the endoscopic group was less than in microsurgical. In the first days after surgery, back and leg pain was less in patients after endoscopic decompression compared to microsurgical due to less soft tissue injury. There is no statistically significant difference of backpain between the groups of patients in 10-12 months after surgery. Before surgery there is no difference in VAS backpain (p = 0.889), ODI (p = 0.191) between endoscopic and microsurgical patients, but leg pain, walking distance were better (p < 0.05) in endoscopic group. Also, there was larger cross-sectional area of dural sac before surgical procedure in endoscopic group (p = 0.018). After surgery backpain decreased and the cross-sectional area of the dural sac increased without a statistically significant difference (p > 0.05) between the groups. Significantly better was ODI, walking distance, leg pain in the endoscopic group (p = 0.021). Surgical treatment in both groups was effective, which is confirmed by the MCID (Minimal Clinical Important Difference) for leg and backpain (VAS), ODI. There is no difference between rate of complications in both groups. Conclusion: Comparative analysis of endoscopic and microsurgical decompression in degenerative lumbar spinal stenosis showed that both methods made it possible to increase the size of the spinal canal and provided regression of clinical symptoms. In the early postoperative period better VAS leg, back pain after endoscopic surgery may be due to less invasiveness of endoscopic surgery, and less preoperative pain in this group. In 10-12 months after surgery there was no statistically significant differences between the groups in VAS back pain. Less leg pain, ODI and walking distance in 11-12 months after surgery in endoscopic group are most likely associated with better baseline values and a larger cross-sectional area of the dural sac. Summarizing the above, we can conclude that the results of the comparison do not allow us to reasonably judge the advantages of one of the methods, which dictates the need for further research. David Shin 1 , Olumide Danisa 2 , Wayne Cheng 3 1 Loma Linda University School of Medicine, Loma Linda, United States , 2 Duke University Health System, Orthopaedic Surgery, Durham, United States , 3 Jerry L Pettis Memorial Veterans Hospital, Orthopaedic Surgery, Loma Linda, United States Introduction: Advancements in correcting kyphotic deformity have attempted to mitigate vertebral fractures and cement leakage of osteoporotic patients. However, osteoporotic patients continue to have high rates of postoperative complications and face significant risks such as subsequent fractures and spacers telescoping into vertebral bodies. This study proposes a novel anterior cement augmentation technique for correction of kyphotic deformity involving an oblique lateral interbody fusion approach. Materials and Methods: Patient 1 underwent a stage-one procedure including anterior lateral L3 corpectomy via an oblique lateral interbody fusion approach. Cement was placed anterolaterally at L2 and L4 and an expandable cage was placed. A stage-two procedure was performed two days following stage one. A posterior T12-to-pelvis instrumented fusion was performed with prophylactic cement augmentation at T11, followed by T12, L1, and L2 vertebral body augmentation. Pontine osteotomy and compression were performed and applied between L2-L4. Patient 2 underwent an anterior C4-T2 and posterior C4-S1 osteotomy and instrumented fusion. The patient developed immediate postoperative instrumentation failure with kyphosis at L4-L5 and instrumentation loosening and migration from L4-S1 within 2 weeks of surgery. The patient then underwent oblique lateral interbody fusion at L4-L5 with anterior cement augmentation, followed by a revision lumbar-pelvis instrumentation. Results: Both patients demonstrated significant kyphotic deformity correction with follow-up records suggesting favorable outcomes. See images. Conclusion: Our anterior cement augmentation technique presents a novel alternative for correction of kyphotic deformity and restoration of sagittal alignment in the lumbar spine of osteoporotic patients. Using a minimally invasive, anterior-to-psoas approach may decrease morbidity of approach related complications. Federico Landriel 1 , Fernando Padilla Lichtenberger 1 , Liezel Ulloque-Caamano 2 , Emily Guerra 1 , Florencia Casto 1 , Santiago Hem 1 1 Hospital Italiano de Buenos Aires, Spine Unit - Neurosurgery, Buenos Aires, Argentina , 2 Hospital Padilla, Neurosurgery, San Miguel de Tucuman, Argentina Introduction: The intraoperative localization of an intercostal nerve schwannoma (INS) is extremely difficult because the lesion is generally not palpable, and the fluoroscopic visualization of anatomic landmarks in the ribs is unsatisfactory. Using activated carbon suspension to mark the soft-tissue approach could improve INS localization. We present a novel, simple, reproducible carbon-assisted minimally invasive transtubular approach for an INS. Material and Methods: The patient was a 57-year-old man with a painful 12th left INS arising below the floating rib. A computed tomography image-guided, tumor-to-skin marking with aqueous carbon suspension was performed 48 hours before surgery. A minimally invasive transtubular approach following the carbon path allowed a precise tumor location. Results: The INS was completely removed. The patient's thoracic radicular pain was immediately relieved after surgery. He was discharged the following day with residual numbness on the left thoracic side. At the 5-year follow-up, no tumor recurrence was noted in the control MRI. Conclusion: This study presents an alternative novel technique for resecting an intercostal schwannoma. Using a transtubular approach with carbon-marking assistance allowed a tumor gross total resection with immediate pain relief and a successful outcome. Varun Agarwal 1 1 Rohilkhand Medical College and Hospital, Orthopedics, Bareilly, India Introduction: Cervical Degeneration and Disc Disease is common entity. It is usually managed by anterior cervical discectomy and fusion and cervical arthroplasty in select cases. However these require general anaesthesia and prolonged recovery. Anterior Percutaneous cervical endoscopy is an out patient procedure done under local anaesthesia for prolapsed intervertebral discs. It a true motion preservation surgery with early recovery and patient discharged same day. Material and Method: This is a study involving 10 patients treated by Anterior Percutaneous cervical endoscopy under local anaesthesia in out patient setting. Patient is laid supine and head fixed with tapes to prevent sudden motion. Level identified under c arm and local anaesthetic infiltrated in skin. Index finger is used to push trachea and oesophagus medially and middle finger is used to push carotid bundle laterally. Usually one can directly palpated bone in the interval. Needle is inserted in disc space under c arm guidance. Then Guide wire is inserted thru needle and needle withdrawn. Incision is expanded to 5 mm. Dilator is inserted over guide wire and working sleeve of endoscope over guide wire. Dilator is removed and endoscope with working channel and continuous irrigation is inserted into disc space. Using endoscopic rongeurs targeted discectomy is done and bipolar is used for bleeding control. Awake and aware patient under local anaesthesia is able to tell immediate relief of radiculopathy on successful fragment removal. This indicates the end of surgery. Endoscope is removed and wound closed with one stitch and patient shifted to recovery and made ambulatory in 3-4 hrs as tolerated. Result: Post operative patient was allowed to walk after 4 hrs of surgery with discharge by 8 hrs post operative. Conclusion: Anterior Percutaneous cervical endoscopy is an out patient procedure done under local anaesthesia for prolapsed intervertebral discs. It a true motion preservation surgery with early recovery and patient discharged same day. Delfina Mazza Elizalde 1 , Carlos Zanardi MD 2 1 Hospital General de Agudos “Dr. Ignacio Pirovano”, Buenos Aires, Argentina , 2 Clinica La Pequeña Familia , Junin , Argentina Introduction: The intermuscular/Wiltse approach for transpedicular screws offers several advantages over the conventional midline approach, including reduced intraoperative bleeding, improved postoperative pain management, lower infection rates, and reduced risk of adjacent level disease. This technique can be employed to address a variety of pathologies such as degenerative, tumoral, trauma and infectious. At our center, through the use of a modified Gelpy retractor we are able to treat different pathologies in both the lumbar and the dorsal spine by means of an intermuscular approach and low-cost equipment. This retractor eliminates the need of a percutaneous system coupled with the tubular system for a 360º spine instrumentation. The use of this retractor, along with our expertise in identifying muscular planes during dissection, has enabled us to apply a minimally invasive philosophy in patient treatment. Material and Methods: From March 2023 to January 2024, we instrumented 68 patients using the intermuscular approach with the modified Gelpy retractor. Fifty-six patients from our total cohort had degenerative pathologies and among them, 51 underwent 360º spine instrumentation (transpedicular screws and transforaminal interbody fusion). Six patients were treated for trauma-related stabilization, five for tumor pathology, and one for infection. The spinal regions treated included 62 lumbar, 2 thoracolumbar, and 4 thoracic cases. The key feature of the retractor is its long, narrow prongs (7 cm long), which provide adequate visualization of the anatomical structures for both screw placement and interbody fusion. Results: The experience in our center has been of optimal therapeutic results in line with what the literature reports about this approach. The average postoperative stay was of one day, no patient required a blood transfusion and postoperative pain was solely managed with NSAID intake. Conclusion: Minimally invasive techniques prioritize muscle preservation and are not solely defined by small incisions. The use of affordable surgical instruments, such as the modified Gelpy retractor, allows us to offer optimal surgical treatment to patients. This retractor facilitates both screw placement and interbody fusion through a transforaminal approach and can be employed in a wide variety of surgical and economic settings. Sunil Chodavadiya 1 1 Bombay Hospital, Orthopaedics, Mumbai, India Introduction: Tubular decompression is a minimally invasive surgical technique commonly used for the treatment of lumbar spinal stenosis. The choice of anaesthesia, whether spinal or general, plays a significant role in the perioperative experience and outcomes of these procedures. However, limited research directly compares the perioperative complications associated with spinal versus general anaesthesia in the context of tubular decompression. Methods: This retrospective comparative study aimed to assess and compare perioperative complications in 180 patients undergoing tubular decompression under spinal versus general anaesthesia. Of these, 100 patients received spinal anaesthesia (Group A), while 80 patients underwent general anaesthesia (Group B). Results: The incidence of perioperative complications, including wound infections, neurological deficits, hematoma formation, and cerebrospinal fluid leaks, was recorded and compared between the two anaesthesia groups. Conclusion: The findings of this study provide valuable insights into the impact of anaesthesia selection on perioperative complications in tubular decompression surgeries. Understanding the differences in complication rates between spinal and general anaesthesia can aid surgeons and anesthesiologists in optimizing patient care and improving surgical outcomes in minimally invasive spinal procedures. Keywords: Tubular decompression, spinal anaesthesia, general anaesthesia, perioperative complications, comparative study. Mario Benvenutti 1 , Misael Salazar-Alejo 1 , Alfonso García-Chávez 2 , Felix Dominguez Cortinas 3 1 Centro Médico Zambrano Hellion, Instituto de Neurología y Neurocirugía, San Pedro Garza García, Mexico , 2 Hospital Ángeles Tijuana, Tijuana, Mexico , 3 Hospital Ángeles Pedregal, Ciudad de México, Mexico Introduction: Cervical spondylotic radiculopathy is a common condition that can lead to significant pain and functional impairment, often requiring surgical intervention when conservative treatments fail. Posterior endoscopic cervical foraminotomy (PECF) has emerged as a minimally invasive surgical option, offering potential benefits such as reduced tissue damage, shorter recovery times, and lower complication rates compared to traditional open surgery. This systematic review and meta-analysis aim to synthesize the existing evidence on PECF, evaluating its clinical outcomes and safety profile in the management of cervical spondylotic radiculopathy. Material and Methods: A comprehensive literature search was conducted across the MEDLINE, Web of Science, and Scopus databases to identify studies relevant to the treatment of cervical osseous foraminal stenosis using PECF. Eligible studies were limited to case series published in English or Spanish. The primary outcome measures assessed included operation time, blood loss, complication rate, length of hospital stay, and patient-reported outcomes such as the Visual Analogue Scale (VAS) for back and leg pain, the Japanese Orthopedic Association (JOA) score, and the Neck Disability Index (NDI). A random-effects meta-analysis was performed to synthesize the pooled effects from the included studies, while the incidence of complications was evaluated using a generalized linear mixed model to account for variability among studies. Results: Out of 692 screened reports, 6 studies met the eligibility criteria, including a total of 333 patients. The NDI scores showed significant improvement at 3 months (RMD 15.21 points, 95%CI 12.02-18.4, p < 0.001), 6 months (RMD 16.7 points, 95%CI 13.47-19.93, p < 0.001), and 12 months (RMD 13.04 points, 95%CI 8.37-17.71, p < 0.001). The mean operation time was 69 minutes (95%CI 54-84 minutes), with an average hospital stay of 5.87 days (95%CI 0.83-0.92 days). The complication rate was low, estimated at 1% (95%CI 0-25%). Due to the limited number of studies, an analysis of the JOA scores and blood loss could not be performed. Conclusion: PECF has shown clinical efficacy in the treatment of cervical osseous foraminal stenosis, as evidenced by significant improvements in VAS-back, VAS-leg, and NDI scores. However, further research is necessary to better understand its effects on blood loss and myelopathic symptoms. Additionally, there is a need for standardized and systematic methods to assess complications, which will improve the accuracy of complication rate estimates and enhance our understanding of the procedure’s overall impact. This will ultimately contribute to refining and optimizing the use of PECF in clinical practice. Takeshi Kaneko 1 , Ryoji Tominaga 2 , Hiroki Iwai 2 1 Inanami Spine and Joint Hospital, Tokyo, Japan , 2 Iwai Orthopedic Hospital, Tokyo, Japan Objective: This study aims to compare the clinical outcomes and irrigation fluid usage between biportal surgery using an arthroscope, also known as unilateral biportal endoscopy (UBE), and using a Uniportal scope in assisted full endoscopic spine surgery (AFESS). While UBE is traditionally performed with an arthroscope, the Uniportal scope offers the advantage of internally managing both irrigation inflow and outflow, which may reduce fluid consumption during surgery. This research evaluates the differences in irrigation fluid usage between UBE and AFESS and their respective clinical outcomes. Methods: From June 2022 to October 2023, 89 patients diagnosed with lumbar spinal stenosis who underwent biportal surgery were analyzed. The UBE group consisted of 52 patients, while the AFESS group included 37 patients. The primary outcome was the measurement of intraoperative irrigation fluid usage per hour. Additionally, postoperative wound pain was assessed using the Numeric Rating Scale (NRS) on the day after surgery, and patient satisfaction scores were compared between the two groups two weeks postoperatively. A multivariate analysis was conducted to evaluate the potential influence of age, gender, and body mass index (BMI) on irrigation fluid usage. Results: Among the 89 patients, 52 underwent UBE, and 37 underwent AFESS. There was no significant difference in patient satisfaction scores at two weeks postoperatively between the two groups, indicating that both procedures achieved comparable clinical outcomes. However, the AFESS group demonstrated significantly lower hourly irrigation fluid usage compared to the UBE group. The multivariate analysis revealed no significant influence of age, gender, or BMI on irrigation fluid consumption in either group. Conclusion: AFESS significantly reduces irrigation fluid usage compared to UBE, which may contribute to reduced medical resource consumption, including the costs associated with fluid disposal. The absence of significant influence from patient characteristics, such as age, gender, or BMI, suggests that the observed difference in fluid usage is likely due to the technical aspects of the surgery. The Uniportal scope’s internal management of irrigation, along with surgical factors like the skin incision, may contribute to the lower fluid usage seen in AFESS. Therefore, AFESS presents a more efficient technique in terms of fluid management, potentially improving surgical efficiency and reducing healthcare costs without compromising clinical outcomes. Kunfeng Song 1 , Daniel Rosenthal 2 1 Third People's Hospital of Henan Province, Minimally Invasive Spine Surgery Center, ZhengZhou, China , 2 Hochtaunus-Kliniken, Minimally Invasive Spine Surgery Center, Bad Homburg, Germany Introduction: To evaluate the short-term efficacy of percutaneous anterior thoracoscopic surgery for the treatment of thoracic disc herniation. Material and Methods: A retrospective analysis was conducted on patients with thoracic disc herniation who underwent percutaneous anterior thoracoscopic surgery from January 2021 to December 2022. Clinical outcomes were assessed using the Visual Analog Scale (VAS) for pain, the Oswestry Disability Index (ODI) for functional status, and radiographic imaging for surgical success. Preoperative and postoperative data were compared to determine the effectiveness of the procedure. Results: A total of 30 patients (18 males and 12 females, aged 35-65 years) were included in the study. The mean follow-up period was 12 months. Postoperative VAS scores significantly decreased from an average of 8.2 ± 1.1 to 2.3 ± 0.9 (p < 0.01). The ODI scores improved from a preoperative mean of 60.4% ± 12.3% to a postoperative mean of 20.5% ± 7.8% (p < 0.01). Radiographic analysis showed successful decompression in all cases with no significant complications such as infections or neurological deficits. Conclusion: Percutaneous anterior thoracoscopic surgery is an effective and minimally invasive approach for treating thoracic disc herniation, offering significant pain relief and functional improvement in the short term. Josh Schroeder 1 , Harem Rouhi 1 , Ohad Einav 1 , Leon Kaplan 1 , Jose Cohen 2 1 Hadassah Medical Center, Department of Orthopedics, Jerusalem, Israel , 2 Hadassah Medical Center, Department of Neurology, Jerusalem, Israel Introduction: Vertebral compression fractures (VCFs) are a common occurrence in the geriatric population, associated with significant patient morbidity. In recent years kyphoplasty, has become a standard method of treatment. Kyphoplasty is a minimally invasive surgical procedure used to treat VCFs. The procedure involves injecting cement into the fractured vertebra to stabilize it and reduce pain. A common complication of kyphoplasty is cement leakage into the spinal canal, which can compress the spinal cord or nerve roots. In this study we aimed to assess the safety and efficacy of the two-phase cement injection technique for kyphoplasty. Material and Methods: A retrospective study was conducted of 150 patients who underwent the two-phase cement injection technique for the treatment of VCFs. The rate of cement leakage, pain relief, functional status, and complications were assessed. Results: The rate of cement leakage was less than 1%. The mean visual analog scale (VAS) pain score decreased from 7.5 ± 1.2 prior to the procedure to 2.1 ± 0.9 at 6 month follow-up. The mean Oswestry Disability Index (ODI) score decreased from 52 ± 12 prior to the procedure to 22 ± 8 at 6 month follow-up. The most common complication was mild back pain, which occurred in 10% of patients. Conclusion: We report our experience with a two-phase cement injection technique for treatment of VCFs. Our findings suggest that this procedure is a safe and effective treatment method. Furthermore, our results indicate that this technique significantly relieves pain and improves functional status with a low rate of complications. Mario Benvenutti 1 , Misael Salazar-Alejo 1 , Alfonso García-Chávez 2 , Felix Dominguez Cortinas 3 1 Centro Médico Zambrano Hellion, Instituto de Neurología y Neurocirugía, San Pedro Garza García, Mexico , 2 Hospital Ángeles Tijuana, Tijuana, Mexico , 3 Hospital Ángeles Pedregal, Ciudad de México, Mexico Introduction: Lumbar spine stenosis is a prevalent condition that significantly impacts quality of life, particularly in the aging population. Traditional surgical approaches, while effective, are associated with considerable morbidity, prolonged recovery times, and potential complications. Posterior full-endoscopic lumbar spine decompression (PFELSD) has emerged as a minimally invasive alternative, offering the potential for reduced surgical trauma and faster recovery. This systematic review and meta-analysis aim to critically evaluate the existing literature on PFELSD, focusing on its clinical outcomes, safety profile, and overall efficacy in treating lumbar spine stenosis. Material and Methods: A literature search was performed using the MEDLINE, Web of Science, and Scopus databases to identify relevant studies. Eligible studies included case series published in English or Spanish that focused on treating central or lateral recess lumbar stenosis with lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD) or interlaminar endoscopic lateral recess decompression (IE-LRD), respectively. The primary outcome measures evaluated were operation time, blood loss, complication rate, length of hospital stay, the Visual Analogue Scale (VAS) for back and leg pain, the Japanese Orthopedic Association (JOA) score, and the Oswestry Disability Index (ODI). A random-effects meta-analysis was conducted to estimate pooled effects across studies, while the incidence of complications was analyzed using a generalized linear mixed model. Results: A total of 1,661 reports were screened, with 18 studies meeting the eligibility criteria, encompassing a total of 1,304 patients. The VAS-back showed a significant reduction at 3 months (RMD 3.92 points, 95%CI 2.88-4.97, p < 0.001), 6 months (RMD 4.49 points, 95%CI 3.69-5.28, p < 0.001), and 12 months (RMD 4.61 points, 95%CI 3.78-5.44, p < 0.001). Similar improvements were observed in the VAS-leg scores at 3 months (RMD 5.31 points, 95%CI 4.65-5.97, p < 0.001), 6 months (RMD 5.64 points, 95%CI 5.03-6.24, p < 0.001), and 12 months (RMD 5.94 points, 95%CI 5.34-6.55, p < 0.001). The JOA scores also indicated significant improvement at 6 months (RMD 11.61 points, 95%CI 4.40-18.81, p < 0.001) and 12 months (RMD 12.06 points, 95%CI 4.93-19.18, p < 0.001). The ODI demonstrated a progressive improvement from 1 month (RMD 32.61%, 95%CI 17.92-47.31%, p < 0.001) through 3 months (RMD 38.43%, 95%CI 27.70-49.15%, p < 0.001), and 6 months (RMD 42.23%, 95%CI 32.43-52.02%, p < 0.001), with sustained benefits at 12 months (RMD 41.56%, 95%CI 32.24-50.88%, p < 0.001) and up to 24 months (RMD 37.1%, 95%CI 22.88-51.32%, p < 0.001). The mean surgical time was 72 minutes (95%CI 63-82 minutes), with a mean blood loss of 21 ml (95%CI 10-32 ml), and an average hospital stay of 3.4 days (95% CI 1.4-5.4 days). The overall incidence of complications was estimated at 6% (95%CI 4%-9%). Conclusion: Additional research is warranted to enhance our understanding of the long-term benefits of this intervention and its impact on myelopathic symptoms. Additionally, there is a need for standardized and systematic methods to assess complications. PFELSD for spinal stenosis has shown a favorable safety profile and significant clinical efficacy, as evidenced by improvements on the VAS-back, VAS-leg, JOA, and ODI scales, with some benefits extending up to 2 years. Nicolás Prada Ramírez 1 , Gabriel Alonso Cuéllar 1 , Jorge Ramirez 1 , José Rugeles 1 , Carolina Ramirez 1 , David Coronado Pantoja 1 1 LESS Invasiva Academy, Research & Education, Bogotá, Colombia Introduction: Spinal fusion or arthrodesis remains the gold standard for treating various degenerative pathologies of the spine, including spondylosis, herniated disc, spondylolisthesis, deformity, and tumors. Despite their advantages and versatility, fusion procedures are associated with different complications, including adjacent segment degeneration (ASD). Fusion surgeries have had a marked increase in patients over 65, creates a significant challenge in treating ASD in elderly patients. Different high-level evidence articles have demonstrated the effectiveness of endoscopic spine surgery (ESS) in managing degenerative spine pathology. Since 2007, with its description, [8] the interlaminar approach for endoscopic discectomy has presented a new alternative for the endoscopic management of degenerative spine disease. The study aims to report the clinical outcomes obtained in patients > 60 with ASD treated with endoscopic surgery using the interlaminar approach. Material and Methods: Patients > 60 years old admitted with radicular symptoms secondary to ASD histories between May 2020 and January 2023 who underwent endoscopic surgery using a uniportal interlaminar approach were retrospectively reviewed. Patient-reported outcome measures (PROMs) were collected, including pre-and postoperative visual analog scale index (VAS), Oswestry ODI criteria, and patient satisfaction with the MacNab criteria. Results: A total of 8 patients were included in the study, including five women and three men with an average age of 72.8 ± 7.89 years. The median time to disease development (between arthrodesis, development of the adjacent segment, and the need for endoscopic surgical intervention) was 63 months ± 58.7 (range, 12-192 months). The average time of the endoscopic interlaminar procedure - including anesthesia time - was 105 ± 50.6 minutes. The estimated volume of blood loss was 19.4 ± 8.63 ml (range, 10-30 ml). The average follow-up time was 23.0 ± 16.7 months. VAS and ODI scores decreased. The difference averaged 5.75 ± 2.12, going from 9.13 ± 0.99 in the preoperative period to 3.30 ± 2.26 (p = 0.014). Likewise, ODI decreased on average by 59 ± 17.3%, going from 80.5 ± 10.7 before the procedure to 21.5 ± 21.1% (p = 0.008). At the last follow-up, the distribution of the MacNab criterion showed 87.5% of excellent and good results (n = 7). the relationship between obesity and AD achieved in the VAS and ODI was analyzed, and it was observed that overweight and obesity were related to worse improvement rates without these results being statistically significant. There were no intraoperative complications; only one case had to be reoperated with a conventional technique. No patient had a hospital stay. Conclusion: Ambulatory uniportal interlaminar endoscopic surgery is a technique that may become a safe and effective alternative for the treatment of symptomatic ASD in patients over 65 years. Patient selection and adequate communication regarding their expectations are essential for better resolution. Research requires greater follow-up and more experimental designs that allow for the determination of its effectiveness and safety. Juliano Dias 1 , Maria Fernanda Negreli 2 , Thiago Martins da 2 1 Hospital Universitário Risoleta Tolentino Neves, Belo Horizonte, Brazil, 2 Universidade Federal de Minas Gerais, Belo Horizonte, Brazil Introduction: The evolution of the spine endoscopic surgery has demonstrated a huge increase in their clinical indications and use. Initially, in the first-generation endoscopic spine surgery, we have seen emerging the transforaminal approach for lumbar disc herniation treatment. After that, have emerged the second generation that was marked using interlaminar approach; and with the use of that, have started the third-generation endoscopic surgery of lumbar decompression in stenosis cases. The fourth-generation endoscopic spine surgery is more clearly been defined using endoscope to arthrodesis purposes. And then, is emerging the fifth-generation endoscopic surgery, that will be used to treat spinal tumors, intradural management of lesions and other diseases related to gentler and challenging intradural maneuvers. In our paper, we have proposed a three-portal endoscopic use to treat and manage intradural lesions, with the convenience of using a bimanual tissue manipulation, that was possible because of using the endoscope in a third fixed portal. Material and Methods: We have used a complete endoscopic set of mono and biportal endoscopes and instruments. Allied to that, we have used an endoscopic holder table arm instrument to fix the endoscope in third portal and it made possible using a bimanual endoscopic procedure. We have prepared the cadaveric specimen and marked our points entrances using the “physics sines law” to triangulate the instruments and then, proceed to endoscopic manipulation. We have drilled the posterior arch of first cervical vertebrae and the base of foramen magnum. With some proper instrument developed by our team, we have opened the dura mater layer and then, have opened the arachnoid layer. Results: With this opening and exposure, we were able to identify the medullar tissue and first cervical radicular components as well as the lower cranial nerves like hypoglossal nerve, spinal component of accessory nerve, and other nerves emerging out from jugular foramen exit. When we have opened the dura layer more cranially, it was possible to identify the gracile and cuneiform tubercles as well as the Magendie foramen and the fourth ventricle floor. After that wonderful exposure and structures identification, we have proceeded to dura mater layer closure using bimanual suture maneuvers that demonstrate that it was possible a good suture with an effective margins closure. Conclusion: We were able to conclude that is possible, feasible and secure the use of multiportals approaches in cadaveric specimens to explore the “intradural universe” using the endoscopic spine approaches. This vertebral endoscopic exposure and manipulation we have called “videovertebroscopy” and it could be the first step of a multiple possible of using the robot assistance in complex spine surgeries in a close future. Rizwan Akram 1 , Zubair Khalid 1 , Latif Khan 1 1 Ghurki Trust Teaching Hospital, Department of Orthopedic and Spine, Lahore Pakistan Introduction: Lumbar disc herniation (LDH) affects 70 to 85 percent of people, often causing significant back pain. While some cases may resolve spontaneously, surgery is needed for those with neurological deficits or persistent symptoms, typically treated with open lumbar microdiscectomy (OLM). However, OLM is invasive and may result in ongoing pain. The unilateral biportal endoscopic (UBE) technique offers advantages like smaller incisions and shorter recovery times. This study evaluates UBE’s efficacy and safety for LDH treatment in Pakistan, aiming to enhance patient outcomes and contribute to global understanding of minimally invasive spine surgery. Material and Methods: A prospective study at Ghurki Trust Teaching Hospital, Lahore, from October 2023 to March 2024, evaluated 50 patients aged 20-60 with lumbar disc herniation and canal stenosis using Owstery Disable Index, visual analogue course and modified McNab’s criteria for satisfaction. All the collected data were entered and analyzed using SPSS version 27 & R-studio version 4.2.1. All the p-value ≤ 0.05 was considered to be statistically significant. Results: In our study, 41 (82.4%), were male patients, while 9 (17.6%) were female cases with a mean age of 40.94 ± 8.76 ranging from 29 to 60 years. A slight majority of patients have right-sided disc herniation (54.1%) compared to left-sided (45.9%). Thee mean duration of symptoms is 8.47 ± 7.30 months, with a range from 1 to 36 months. The average length of hospital stay is 1.41 ± 0.76 days ranging from 1 to 4 days. The mean ODI score significantly decreased among patients indicating improvemnet in functional outcome nad pain score was significantly.Preoperative scores averaged 32.96, reflecting moderate disability. Postoperative scores showed a drastic reduction: 10.69 on the day of surgery, 8.31 on the first postoperative day, and further decreases to 3.35 at three weeks, 1.27 at six weeks, and 0.58 at twelve weeks 87% patients did not have any complication after surgical intervention .2 cases of Dura was reported but with no post-op problems. According to Modified Macnab Criteria, 70.59% of patients were very satisfied, indicating no pain. Conclusion: Our results showed that this technique is safe and effective as other MIS techniques, majority of our patients showed significant improvement after surgery. Keywords: Unilateral Bi-portal endoscopy, Lumbar disc herniation, Oswestry Disability Index (ODI) Vadim Byvaltsev 1,2,3 , Andrei Kalinin 1,3 , Marat Aliyev 4 , Bobur Yussupov 4 , Yurii Pestryakov 1 , K. Daniel Riew 5 6 1 Irkutsk State Medical University, Neurosurgery, Irkutsk, Russian Federation , 2 Irkutsk State Medical Academy of Postgraduate Education, Traumatology, Orthopedic and Neurosurgery, Irkutsk, Russian Federation , 3 Railway Clinical Hospital, Neurosurgery, Irkutsk, Russian Federation , 4 Asfendiyarov Kazakh National Medical University, Neurosurgery, Almaty, Kazakhstan , 5 Columbia University, Orthopedic Surgery, New York, United States , 6 Weill Cornell Medical Schoo, Neurological Surgery, New York, United States Introduction: Combination of degenerative spinal canal stenosis in the cervical and lumbar spine is described in the literature as tandem stenosis. This pathology is detected in more than 25% of cases in people over 50 years of age. The widespread nature of degenerative changes of the spinal segments determines the different nature of neurological manifestations, which complicates the diagnosis and treatment tactics of such patients. The purpose of this study was to evaluate the results of surgical treatment in patients with cervical and lumbar tandem stenosis after dorsal simultaneous operations. Material and Methods: The study included 45 patients with cervical and lumbar tandem stenosis. We performed posterior decompression both the cervical as well as lumbar spine. Total operative time, estimate blood loss, length of hospitalization, complications and clinical data (NDI score, ODI score, VAS neck pain score, VAS arm pain score, VAS back pain score, VAS leg pain score, Macnab scale) were analyzed. Results: The average total duration of the surgery was 132 (100; 153) min, median of the total blood loss - 200 (160; 280) ml. All patients were activated the next day after the operation. A significant decrease of pain according to VAS after operation registered: neck pain from 76 (63; 84) to 8 (4; 18) (p = 0.002), arm pain from 87 (71; 92) to 4 (0; 8) (p < 0.001), back pain from 62 (54; 72) to 10 (6; 17) (p = 0.004), leg pain from 89 (73; 98) mm to 4 (2; 6) (p < 0.001). An improvement in the functional state according to NDI from 36 (32; 44) points to 4 (2; 6) points (p < 0.001) and ODI from 66 (54;72) points to 10 (4; 12) points (p < 0.001). Most patients noted the effectiveness of the surgery according to Macnab scale as excellent and good - 84%. Postoperative complications were recorded in 3 cases (6.7%). Conclusion: Simultaneous dorsal surgery for cervical and lumbar tandem stenosis have low number of postoperative complications, as well as high clinical efficacy confirmed by a decrease in the severity of the pain syndrome and improvement of the functional state. Rodrigo Lima 1 1 Hospital Santa Lucia, Brasilia-DF, Brazil Introduction: There has been rapid technological advancement in guided navigation for minimally invasive surgery over the past two decades, and these technological advancements make it an invaluable assistant for surgeons, essentially enabling virtual reconstruction of the patient’s anatomy in real-time. The goals of these navigation and robot-assisted procedures are to reduce the likelihood of neural and vascular injury, decrease hospital stay, reduce bleeding and postoperative pain, shorten healing time, and lower infection rates. Material and Methods: A single-center retrospective cohort study was conducted evaluating the pre- and postoperative clinical and radiographic outcomes of the first patients in Latin America with a diagnosis of lumbar degenerative disease who underwent lumbar interbody fusion, L4-L5 via LLIF - Single Position Prone approach. A total of 80 patients (40 assisted by fluoroscopy, 40 - assisted by robotics) - 320 percutaneous pedicle screws were evaluated. Results: The primary outcomes analyzed and compared were the radiation exposure to the team per screw (seconds), the skin-to-skin operation time (minutes), and recovery time (days). Secondarily, observed outcomes included lumbar pain intensity (Visual Analog Scale - VAS), reported functional disability (Oswestry Disability Index), and any potential complications. All secondary outcomes were collected postoperatively. Comparing MIS interventions with free-hand instrumentation and robotic instrumentation, a statistically significant difference was identified in radiation time per screw and in surgery time. Conclusion: The literature on the Robotic Spine Surgery is limited; however, MIS surgery with robotic assistance appears advantageous in terms of radiation exposure and surgical time. Vadim Byvaltsev 1,2,3 , Andrei Kalinin 1,3 , Yurii Pestryakov 1 , Dmitriy Hozeev 1 , K. Daniel Riew 4 5 1 Irkutsk State Medical University, Neurosurgery, Irkutsk, Russian Federation , 2 Irkutsk State Medical Academy of Postgraduate Education, Traumatology, Orthopedic and Neurosurgery, Irkutsk, Russian Federation , 3 Railway Clinical Hospital, Neurosurgery, Irkutsk, Russian Federation , 4 Columbia University, Orthopedic Surgery, New York, United States , 5 Weill Cornell Medical Schoo, Neurological Surgery, New York, United States Introduction: To date, there are no studies in the specialized literature that compare long-term neurological outcomes and return to work after conservative and surgical treatment of lumbar intervertebral disc herniations in railway workers. In addition, numerous risk factors of the production process that cause the progression of spinal degeneration make the above-mentioned cohort of patients unique, which was the impetus for a comprehensive analysis of their treatment results. The purpose of this study was to study of long-term neurological outcomes and analysis of return to work rate after conservative and surgical treatment of lumbar disc herniations (LDH) in railway workers. Material and Methods: The results of treatment of 2329 patients with LDH treated in 2010-2020 at the Neurosurgery Center of the Irkutsk Clinical Hospital were analyzed. Two groups of patients with a single-level LDH at the L4-L5 or L5-S1 with radicular compression pain syndrome were identified: they were treated conservatively (group I, n = 782) and using microsurgical or endoscopic discectomy (group II, n = 809). The clinical outcomes of 683 patients in group I (87.3%) and 718 patients in group II (88.7%) were assessed within 4.6 to 13.2 years after the initial discharge from the neurosurgical department. For comparative analysis the following were used: neurological examination, visual analogue scale of pain for the lumbar spine and lower extremities, ODI and SF-36, average periods of temporary disability, return to work rate, readmissions, complications and reoperations. Results: At baseline patients of two groups were comparable according to clinical data, anthropometric parameters and preoperative workload intensity. Conservative and surgical strategies for providing neurosurgical care to railway workers with lumbar IVD hernias in the late period contributed to the improvement of clinical parameters. At the same time, in the group of patients initially subjected to surgical treatment, better neurological outcomes and a higher frequency of return to work rate, as well as a smaller average number of days of incapacity for work and the number of readmissions, complications and reoperations were registered compared with the group of long-term conservative treatment of lumbar IVD hernias in railway workers. Conclusion: In this single-center study involving railway workers with lumbar IVD hernias, surgery strategy was superior to conservative care with respect to pain intensity, functional status, life quality and return to work rate at long term follow-up. Gabriel Alonso Cuéllar 1 , Nicolás Prada Ramírez 1 , Jorge Ramirez 1 , Carolina Ramirez 1 , José Rugeles 1 1 LESS Invasiva Academy, Research & Education, Bogotá, Colombia Introduction: The COVID-19 pandemic was a complex situation that extremely rapidly influenced the way of life of most of the planet's population. One of the most affected disciplines was the medicine. Added to all the health challenges that health professionals faced, medical education - formal and continuing - was utterly suspended due to quarantines and isolation measures. As a response to the impossibility of developing face-to-face content, educational processes had to be implemented taking advantage of technologies, and thus, the adoption of a pedagogical methodology that until then had been explored in a limited way or just as a complement to teaching processes: virtual medical education (VME). Considering the above, a synchronous virtual course in Endoscopic Spine Surgery (ESS) was developed for spine surgeons but complemented with a series of surveys that would allow measuring the impact that VME may have had on the clinical practice of the participating specialists. This study aims to report the experience with a new virtual learning model in ESS and measure the impact and perceptions of surgeons from more than 27 countries participating in the course. Material and Methods: During August and December 2020, a virtual ESS course was implemented. Then, a descriptive cross-sectional study was carried out in which, through three surveys implemented at three different times, health personnel related to and interested in ESS were asked about their experience, perceptions, and impact of a synchronous VME program. The first survey was before starting the activity; the second was after 20 days of finishing the activity; and, finally, the third was a year after having answered the second survey. Results: 996 specialists from 27 countries from 4 continents (America, Europe, Asia, and Africa) were enrolled. Regarding the health profession, among the preliminary enrollees, there were 42.8% orthopedists, 29.4% neurosurgeons, and 3% anesthesiologists. The adherence (participants who completed the learning model requirements and obtained certification) was 37%, with participants reporting 97.8% satisfaction with a score greater than 8 points out of 10. The 93.1% stated that the course significantly contributed to their clinical practice. After 1.11 ± 0.08 years of completing the course, the percentage of participants who had performed some ESS went from 39.2% to 60.8% (p < 0.05). After one year, 63.6% of those surveyed indicated having completed some other training process between face-to-face conferences, cadaver courses, surgical stays, and formal programs. Conclusion: Based on the findings of this study, it can be concluded that VME can be a helpful tool in the teaching processes of surgical techniques, expanding the audience, making it multicultural, and taking advantage of discussion spaces. It cannot be considered the only way to train skills and abilities, but it maximizes the time of this other type of training. Technological and simulation tools clearly must be complemented with practical activities. However, what is reported in this study shows excellent potential for the expansion of ESS techniques in Ibero-Latin America, which will translate into benefits for spine patients. Gabriel Alonso Cuéllar 1 , Nicolás Prada Ramírez 2 , Jorge Ramirez 3 , Carolina Ramirez 3 , José Rugeles 3 , Viviana Plazas Bedoya 3 1 LESS Invasiva Academy, Research & Education, Bogotá, Colombia , 2 Clínica Foscal Internacional, Bucaramanga, Colombia , 3 Clínica Reina Sofía, Bogotá, Colombia Introduction: Spinal pathologies are commonly reported in high-performance athletes (HPA). Lumbar pain prevalence in HPA is comparatively higher than in the general population. At the elite level, more than 30% of professional athletes report lumbar pain during their sports career, being the leading cause of loss of active playing time. Along with an increased rate of presentation of spinal pathologies, tread HPA implies the additional clinical challenge of offering the patient a rapid return to activity in conditions of competence at least equal to those he or she previously had. To reach a successful return-to-play (RTP) criteria (defined as a return to the active roster for at least one professional regular season game after treatment), the first treatment option should be medical management, which is effective in a high percentage of cases. Conventional surgery has proven to be an effective treatment option. Between 75% and 100% of athletes return to activity after an open surgical procedure. However, some athletes who undergo surgery with traditional techniques for the management of spinal disease are often unable to recover to their preoperative sporting level, and the recovery time is longer. Considering the importance and dependence on the preservation of vital anatomy for the maintenance of function in athletes, Endoscopic Spine Surgery ESS is positioned as a motion preservative surgery, reducing the surgical morbidity associated with muscle dissection and denervation of the structures responsible for the functional stability of the spine. In this study, we report the results of ESS in high-performance athletes with lumbar axial pain. Material and Methods: This is a retrospective case series where we analyze the medical records of high-performance athletes' patients treated with ESS for lumbar radicular pain. The inclusion criteria considered: (1) high-performance athletes with cervical or lumbar pain of more than six months of evolution and whose medical management - including epidural injections ESI - has been unsuccessful; (2) without any instability evident on plain and dynamic X-ray in the segments adjacent to the fusion. The exclusion criteria were (1) patients for whom a minimum clinical follow-up of 6 months was not achieved, (2) previous surgery, and (3) patients with symptoms of depression. Results: ESS procedures were performed on 9 patients. The most intervened level was L4-L5. At 24 months of follow-up, the VAS had an average reduction of 7.1 points, and the ODI dropped an average of 41.5 points. Furthermore, for the Macnab criterion, 90% of the patients were completely satisfied with the treatment. The average return to training was 16,8 days; for high-performance sports activity, it was 65.5 days. The performance percentage after surgery was 105%. Conclusion: Spine degenerative diseases in athletes are an important pathology; its correct diagnosis and adequate treatment increase the possibility of achieving the athlete's return and continuity. ESS using local or regional anesthesia and mild sedation could be a feasible and beneficial alternative for surgical management of radiating low back pain in patients who perform high-performance sports activities. Emilson Camapum 1 , Tiago Nobre 2 , Flavio Lima 3 , Benicio de Lima 3 , Baldomero Soares 4 1 Sarah Network of Rehabilitation Hospitals, Neurosurgery, Brasília , 2 Escola Superior de Ciências da Saúde, Medicine, Brasília , 3 Hospital da Criança de Brasília, Neurosurgery, Brasília , 4 Hospital de Base do Distrito Federal, Neurosurgery, Brasília Introduction: Diastrophic dysplasia (DTD) is a rare disorder that affects the development of cartilage and bone. It is an autosomal recessive skeletal dysplasia that results in short stature with limb shortening, contractures of large joints, spinal deformities, cleft palate, clubfoot, cystic swelling of the external ear and deformities of the hands. The spine frequently develops excessive lumbar lordosis, cervical and thoracolumbar kyphosis, and scoliosis. Spinal stenosis can also be found, but it is less commonly reported. Material and Methods: This study retrospectively reports a case of congenital spinal stenosis caused by DTD, leading to conus medullaris syndrome in a pediatric patient, which was treated using full endoscopic bilateral over-the-top decompression through an interlaminar technique. Results: The patient achieved complete symptomatic recovery without any perioperative complications from the procedure. Conclusion: This is the first report of a full endoscopic decompression for spinal stenosis caused by DTD in the literature. Also, this is the first report of full endoscopic decompression for congenital spinal stenosis in a pediatric patient. Cristiano Menezes 1,2,3 , Juan Cárdenas 1,2 , Luca Cordeiro 4 , Guillermo Julio Tatis 5 , Gabriel Lacerda 2 6 1 Columna Institute, Belo Horizonte, Brazil , 2 Hospital Vila da Serra, Orthopedics/Spine Surgery, Belo Horizonte, Minas Gerais, Brazil , 3 Federal University of Minas Gerais (UFMG), Locomotor System, Belo Horizonte, Brazil , 4 Hospital Pequeno Príncipe, Orthopedics/Spine Surgery, Curitiba, Brazil , 5 The Panama Clinic, Orthopedics/Spine Surgery, Ciudad de Panamá, Panama , 6 Hospital Felício Rocho, Orthopedics/Spine Surgery, Belo Horizonte, Minas Gerais, Brazil Introduction: Anterior lumbar interbody fusion (ALIF) is the gold standard for realignment, spinopelvic correction, and indirect decompression. When combined with lateral and posterior procedures, it enhances arthrodesis rates and improves postoperative outcomes. However, one of the problems of this technique is the need for repositioning of the patient to perform lateral and posterior procedures, increasing surgical and anesthesia time, as well as the complications related to it. As a solution to this problem, ALIF in lateral position (L-ALIF), a modification of the original technique, was described, preserving its advantages and making the surgery compatible with single position 360º fusion procedures. The technique requires the surgeon to have a broad knowledge of abdominal and retroperitoneal anatomy, which is often unfamiliar to the spine surgeon. Therefore, in most cases, a vascular surgeon is responsible for access and exposure of the disc segment to be operated on due to his familiarity with the retroperitoneal structures. However, experienced spine surgeons, with a large number of cases, a long learning curve and mastery of the technique, perform their own access when the vascular anatomy is favorable with the same safety and efficiency. The study shows data from 150 patients undergoing L-ALIF in a center without a routine access surgeon. Material and Methods: Retrospective analysis of databases collected from May 2019 to May 2024 by the same spine surgeon at a center without a routine access surgeon. Patients with symptomatic degenerative disc disease refractory to conservative treatment with or without sagittal malalignment were included. Patients with previous abdominal or retroperitoneal surgeries were excluded. Data collected included: Age, comorbidities, body mass index (BMI), visual analogue scale (VAS), intraoperative data and complications. Results: Forty-eight percent (N = 72) of patients were women and 52% (N = 78) were men, with a mean BMI of 28.5 (range 19.9-41.3) and a follow-up time of 28.2 months (range 4-64 months). Among comorbidities, diabetes was the most common in 12.3% of cases. The diagnosis were degenerative disk disease with foraminal stenosis (66.3%), followed by spondylolisthesis (23.2%), pseudoarthrosis (7.1%), adjacent disk disease (2.7%) and spondylodiscitis (0.66%). One hundred and twenty-one patients underwent bilateral posterior pedicle fixation, the most common association being LLIF with transpsoas technique (62.5%) and twenty-nine patients were left standalone. The surgical time and estimated blood loss related to the L-ALIF procedure alone were 95 minutes and 178 ml, respectively. The hospital stay was 2.64 days overall and 1.2 days in patients undergoing standalone. The mean preoperative VAS was 6.98, decreasing to 2.42 postoperatively. The identified complications were vascular injury (9.33%), of which only 2% required direct repair, followed by incisional hernia (3.5%). Conclusion: The analysis shows the efficacy, safety and low incidence of complications in L-ALIF surgeries performed without a routine access surgeon, being a reliable technique, however demanding, due to its learning curve and need for mastery of retroperitoneal anatomy. Kristine Mae Andujare 1 , Jose Miguel Marco Lumawig 1 1 The Medical City, Pasig City, Philippines Introduction: Lumbar interbody fusion has become a standard procedure in spine surgery, evolving with technological advances to include both open and minimally invasive techniques. Among the most common approaches are Open Transforaminal Lumbar Interbody Fusion (TLIF) and Minimally Invasive TLIF (MIS-TLIF), each with unique advantages and challenges. This research seeks to explore the perceptions of Filipino spine surgeons, particularly members of the Philippine Spine Society, regarding these two methods. The study will address whether previously identified barriers to MIS-TLIF, such as technical difficulty, limited training, and radiation exposure, remain relevant and if new challenges have emerged. Through a survey-based approach, this study aims to identify surgeon preferences, their impact on patient care, and potential ways to increase the accessibility and feasibility of MIS-TLIF in the Philippines. Material and Methods: This study utilized a cross-sectional survey design to assess the perceptions of Filipino spine surgeons regarding Minimally Invasive (MIS-TLIF) versus Open Transforaminal Lumbar Interbody Fusion (TLIF). Data was collected through a validated online questionnaire distributed to members of the Philippine Spine Society (PSS) via various communication channels. The survey included sections on demographic information, perceptions and preferences, surgical decision-making, patient care, and the future of minimally invasive spine surgeries. Data was analyzed using descriptive statistics for quantitative responses and thematic analysis for open-ended questions. Confidentiality was strictly observed, with all responses anonymized and securely stored. Statistical tests were applied to compare preferences and identify factors influencing surgical decisions, ultimately aimed at improving MIS-TLIF adoption and accessibility in the Philippines. Results: The results show that 83% of the surveyed spine surgeons responded, with the majority being male (89.57%) and practicing in urban settings (93.04%). Most worked in private hospitals (43.48%) and had access to essential resources like spine implants (91.30%) and imaging modalities (95.65%). Surgeons showed a neutral preference between open and MIS-TLIF surgeries, with surgeon training being the top factor influencing their choices. MIS-TLIF was favored for faster recovery and less trauma, though cost (41.74%) and radiation exposure (26.09%) were significant drawbacks. Postoperative pain management mainly involved medication (98.26%), and patients undergoing MIS-TLIF had significantly shorter hospital stays than those receiving open TLIF. Surgeons highlighted technical difficulty, radiation, and limited training as barriers to adopting MIS-TLIF, suggesting that increased training and cost reduction could encourage its wider use. Conclusion: This study explored the preferences, perceptions, and limitations of Filipino spine surgeons regarding minimally invasive spine surgery (MISS), specifically MIS-TLIF. With a response rate of 83%, the findings indicate a neutral preference between MIS-TLIF and open TLIF, with surgeon training, patient characteristics, and surgical outcomes being key influencers. While MIS-TLIF is favored for its faster recovery and reduced postoperative pain, significant barriers, such as high costs, limited training, and restricted access to equipment, hinder wider adoption. Surgeons acknowledge the potential benefits of MISS, but overcoming these challenges through improved training, resource allocation, and cost reduction is essential for its broader implementation in the Philippines. Chang-Il Ju 1 1 Department of Neurosurgery, Chosun University, College of Medicine, Gwangju, South Korea Background: Transforaminal decompression for foraminal stenosis is very useful technique of full endoscopic surgery. However, L5-S1 foraminal stenosis is very difficult due to anatomical limitations such as large L5 transvers process, iliac crest. narrowed transforaminal entry zone. However, L5-S1 foraminal stenotic lesions could be decompressed by full endoscopic surgical approach. The purpose of this study was to determine the efficacy and feasibility of full endoscopic lumbar foraminotomy PELF) for exiting nerve decompression from lateral recess, foraminal to extraforaminal zone stenosis of the L5-S1. Methods: A retrospective study was performed on 50 patients who underwent full endoscopic transforaminal approach due to coexisting lateral recess, foraminal, and extraforaminal stenosis at the L5-S1 level. L5 Transvers process, isthmus, base of Superior articular process of S1, L5-S1 discectomy, tip of SAP of S1 was decompressed in turn. Postoperative radiculopathic leg pain were analyzed. Visual analog scale (VAS) pain scores, modified Oswestry Disability Index (ODI) scores, and MacNab criteria for evaluating pain disability and response were analyzed. Results: The L5-S1 foraminal stenosis type was divided into lateral recess type (n = 13, 26%), foraminal type (n = 21, 42%), extraforaminal type (n = 7, 14%) and combined type (n = 9, 18%). The mean visual analog scale score for radiating leg pain, assessed preoperatively and at 6 months and 12 months postoperatively, improved from 7.3 ± 1.7 to 2.52 ± 1.02, 2.31 ± 1.35, respectively. The mean Oswestry Disability Index improved from 61.53% preoperatively to 23.5% at 6 months and 15.8% at 12 months postoperatively. 5 complications were detected after PELF. Conclusions: Full endoscopic transforaminal decompression is an effective procedure to resolve combined stenosis (lateral recess, foraminal, and extraforaminal region) with one surgical approach at the L5-S1 level. This technique can decompress directly DRG and facet joint preserving procedure in lateral recess, foraminal and extraforaminal decompression. Gunter Munguia 1 , Helmut Munguia 2 , Marco Medina 1 1 Clinica Internacional, Unidad de Columna y Medula Espinal, Lima, Peru , 2 Discal Centro, Lima, Peru Full endoscopic lumbar discectomy is a minimally invasive technique that has been used in different countries since the late 1980s for the treatment of herniated discs. Objective: To describe the results of full endoscopic lumbar disectomy in a series of patients with complex lumbar hernias. Materials and Methods: In a group of 150 patients and 180 discs operated between July 2021 and 2024 in Lima, Peru. Data such as age, sex, clinical image and imaging abnormalities using TEM and MRI were collected. And the cases were selected according to the Classification of Hyeun Sung Kim et al. The Oswestry scores (ODI) pre and postoperatively were assessed at 8 weeks after the procedure. Macnab criteria, operation duration, hospitalization time, surgical complications and the need for reintervention for cases with score 4 grade IV were also evaluated. Results: 15 patients and 16 herniated discs were operated on. Score 4 grade IV. The average reduction in ODI at 8 weeks was 48 points (SD = 5), representing an average reduction percentage of 85% (SD = 8). According to Macnab criteria, 86.6% of patients had a good evolution, 13.3% had a fair evolution. The average surgery time was 110 minutes and the hospitalization time was 27.2 hours. Conclusions: In our series of surgical patients with complex lumbar herniated discs, full endoscopic lumbar discectomy proved to be a technique with very good results in pain reduction, short surgical duration, no complications and short hospital stay. Don Park 1 , Thomas Olson 2 , William Sheppard 2 1 UC Irvine, Orthopaedic Surgery, Orange, United States , 2 UCLA, Los Angeles, United States Objective: This study aims to establish patient-specific variables that contribute to the necessity for an overnight or inpatient stay following a single or double level dual portal lumbar endoscopic decompression. Methods: A retrospective analysis was conducted on 84 patients who underwent one- or two-level lumbar decompression with a preoperative indication of lumbar disc herniation and/or central canal stenosis. Trauma, tumor, infection, and revision cases were excluded. Patients were divided into cohorts of same-day discharge and those staying one or more nights in recovery. Patients were scored using a proposed fragility index score according to age, body mass index (BMI), procedure performed, and existing comorbidities ranging from 0 to 20 points. Sarcopenia as a contributing factor was quantified using a previously established psoas muscle index (PMI) as a ratio of psoas muscle cross sectional area over bone cross sectional area in preoperative imaging. Cutoff values for predicting hospital stay were analyzed using Youden’s J statistic and receiver operating curve (ROC) analysis. Results: Same-day surgical patients were found to be younger than inpatients (55.3 v. 68.5, respectively; p = 0.0003) and had a lesser American Society of Anesthesiologists (ASA) score (2.0 v. 2.7; p < 0.0001) and Charlson Comorbidity Index (1.6 v. 3.5; p < 0.0001). There was no difference in mean BMI (p = 0.4341). Outpatients were significantly more likely to undergo discectomy, whereas inpatients were more likely to undergo unilateral laminectomy for bilateral decompression (p < 0.0001). Inpatients were additionally more likely to undergo two-level surgery (p = 0.0014). Upon contribution of these variables to the proposed fragility scoring system, a cutoff value of ≥ 9 points was found to predict a stay of one or more nights with an area under the curve (AUC) of 0.791. There was no difference in PMI between inpatient and outpatient groups (p = 0.6732), with an AUC of 0.417. This relationship remained upon stratification by gender, with an AUC for males and females 0.482 and 0.487, respectively. The correlation between the proposed fragility score and PMI is -0.130. Conclusion: The fragility scoring system proposed in this study demonstrates a significant ability to predict the likelihood of an inpatient stay following single or double-level dual portal lumbar endoscopic decompression, with a cutoff score of ≥ 9 points. This score incorporates patient-specific factors such as age, comorbidities, and surgical procedure. The absence of a significant difference in BMI and PMI suggests that body habitus and sarcopenia are less predictive of hospital stay duration in this context. The fragility index can serve as a useful tool in preoperative planning, helping to identify patients at higher risk for extended recovery times and optimizing resource allocation in surgical care. Monty Khela 1 , Obiajulu Agha 2 , Lisa Bonsignore-opp 2 , Mark Xu 2 , David Gendelberg 2 , Ashraf El Naga 2 1 Creighton University School of Medicine, Omaha, United States, 2 University of California, San Francisco (UCSF), Orthopaedic Surgery, San Francisco, United States Introduction: Displaced U-type spinopelvic dissociations present significant challenges due to the associated instability, focal kyphosis, and potential for long-term disability. Traditional open surgical techniques often result in significant soft tissue trauma and prolonged recovery times. A minimally invasive reduction technique utilizing percutaneous methods offers an alternative, allowing for effective reduction of sacral kyphotic deformities while minimizing soft tissue damage and postoperative complications. We introduce a novel percutaneous spino-pelvic reduction technique for treating displaced U-type sacral fractures with associated focal kyphosis, highlighting its advantages in terms of biomechanical stability and clinical outcomes. Material and Methods: The novel technique involved the use of percutaneous external fixation combined with transiliac trans-sacral screw placement and S1-pelvis fixation. Under fluoroscopic guidance, external Schanz pins were placed bilaterally in the S1 pedicles and iliac crests. A controlled reduction of the sacral kyphosis was achieved by applying a lordotic force through the Schanz pins, followed by fixation using a trans-sacral screw and S1-pelvic screws. The use of the external fixator provided provisional stability, allowing for fine-tuning of the reduction before final fixation. The technique ensured minimal disruption to the soft tissue envelope, reducing operative time and intraoperative blood loss, and avoidance of crossing the lumbosacral junction. Results: Postoperative imaging confirmed a 20-degree reduction in sacral kyphosis (from 37.1 degrees preoperatively to 17.1 degrees postoperatively), with excellent hardware placement and restored spinopelvic alignment. Functional improvements were notable, with bilateral lower extremity motor strength improving from 4/5 preoperatively to 5/5 at discharge. The patient was able to mobilize with minimal assistance, and early weight-bearing was achieved without complication. No wound infections or hardware-related complications were observed. Conclusion: This novel percutaneous spino-pelvic reduction technique offers a safe, effective, and minimally invasive option for managing U-type sacral fractures with focal kyphosis. The technique demonstrated substantial reduction in sacral deformity similar to what has been reported in prior open series, with immediate patient functional improvement and minimized soft tissue trauma compared to traditional open techniques. By preserving the soft tissue envelope and utilizing percutaneous methods, this approach may reduce perioperative morbidity and expedite recovery, proving to be a valuable alternative for complex sacral fractures. Future studies should further evaluate the long-term outcomes and potential applications of this technique in broader clinical contexts. Miguel Carvalho 1 , Miguel Varzielas 1 , Eduardo Mendes 1,2 , João Morais 1,3 , Alfredo Carvalho 1,4 , Joana Araújo 5 1 Hospital CUF Viseu, Viseu, Portugal , 2 Centro Hospitalar Tondela-Viseu, Viseu, Portugal , 3 Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal , 4 Centro Hospitalar e Universitário Cova da Beira, Covilhã, Portugal , 5 Neurosafe, Lda, Viseu, Portugal The development of neurological deficit following spinal surgery is a devastating complication. Some of these complications are known to occur without any recognizable adverse event during surgery. Recently, multimodality intraoperative neurophysiological monitoring (IONM), including somatosensory-evoked potentials (SSEPs), motor-evoked potentials (MEPs), and electromyography (EMG) has been utilized and has been proven effective for preventing neurological injury during spinal surgery. Few studies have investigated the clinical meaning of an improved IONM signal during surgery. Recent studies describe that signal improvement during surgery can rule out intraoperative neural injury and neurological function can be expected to improve post-operatively. In the present study the authors retrospectively reviewed patients submitted to decompressive lumbar endoscopic surgery with the use of IONM. From September, 2018 to May, 2024, 66 endoscopic surgical and IONM reports were reviewed. Uni-portal approach was performed in 47 cases with 33.3% of total surgeries being Uni-portal Transforaminal (UTF), 37.9% Uni-portal Interlaminar (UIL) and 28.8% Biportal Interlaminar (BIL). The more frequent surgery was UIL L5-S1 decompression. One patient had a neurological complication with need for emergent open surgical revision after UIL approach. Three patients needed revision surgery weeks after for same level disk herniation one of which was reoperated by the same surgical approach (UIL)and the other two by MISS approach. IONM improvement were recorded in 43.9% of surgeries. Surgeries performed for acute sciatic pain had the higher rate of IONM signal improvement (54.2%), high above surgeries performed for chronic sciatic pain (40%) or neurogenic claudication (33.3%). Timing of the improvement on IONM revealed that, on average, it occurs at 60% of total surgery time. This study reveals that improvement on IONM signals is frequent on endoscopic surgeries and it can be helpful in preventing neurological injury. These signal improvements on IONM can be another intra-operative clue for surgery completeness which can lead to reduced surgical time. Clinical studies must be designed to assess if improvement IONM signals can lead to favorable clinical outcomes. Kunfeng Song 1 , Hejun Yang 1 1 Third People's Hospital of Henan Province, Minimally Invasive Spine Surgery Center, ZhengZhou, China Introduction: To explore the innovation and clinical application value of bloodless unilateral biportal endoscopy (UBE) in minimally invasive spine surgery. Material and Methods: 80 patients with lumbar spine diseases treated between January 2020 and January 2023 were selected as the study subjects, all of whom underwent UBE minimally invasive spine surgery. The patients were randomly divided into two groups: the conventional UBE group (40 cases) and the bloodless UBE group (40 cases). Both groups underwent surgery using the unilateral biportal endoscopy technique. In the bloodless UBE group, optimized endoscopic channels and drainage systems were designed to achieve almost bloodless visualization during surgery. The operation time, intraoperative blood loss, postoperative recovery time, incidence of complications, and clinical outcomes were compared between the two groups. Results: The bloodless UBE group showed significantly better results than the conventional UBE group in terms of intraoperative blood loss, operation time, and postoperative recovery time (p < 0.05). Additionally, patients in the bloodless UBE group had significantly lower postoperative pain scores, shorter hospital stays, and a lower incidence of complications (p < 0.05). Conclusion: The bloodless UBE minimally invasive spine surgery technique, through innovative surgical channels and equipment improvements, achieves almost bloodless operation during surgery, significantly reducing surgical risks and complications and shortening postoperative recovery time. This technique provides a safer and more efficient treatment option for minimally invasive spine surgery, with broad clinical application prospects and promotion value. Pranit Kumaran 1 , Ishan Shah 1 , Andy Ton 2 , Vivek Satish 1 , William Karakash 1 , Jacob Ball 1 , Jeffrey C. Wang 1 , Raymond Hah 1 , Ram Alluri 1 1 Keck School of Medicine of USC, Los Angeles, United States , 2 University of California, Department of Orthopedic, Los Angeles, United States Introduction: Lumbar decompression procedures are a standard treatment for lumbar spinal stenosis (LSS). Recent advancements have focused on minimally invasive surgery (MIS) approaches, aiming to improve clinical and patient-reported outcomes compared to traditional open techniques. The L4-L5 spinal level is most frequently associated with LSS and is the most common site for operative decompression. This study compares MIS and open surgery for L4-L5 decompression, evaluating both perioperative and patient-reported outcomes. Material and Methods: A retrospective analysis was conducted on patients who underwent L4-L5 decompression (laminectomy/laminotomy) for LSS between 2015 and 2023 at a single tertiary academic hospital. Exclusion criteria included age < 18 years, history of lumbar fusion, undergoing lumbar concurrent fusion, and surgical indications for trauma, malignancy, or infection. Outcome measures included estimated blood loss (EBL), pain Numerical Rating Scale (NRS), Oswestry Disability Index (ODI), operative time (OT), complications, length of stay (LOS), and reoperation rates. Cohorts were 1:1 propensity matched for age, sex, body mass index, American Society of Anesthesiologists (ASA) class, smoking status, diabetes, osteoporosis, and number of levels decompressed. Statistical analysis was done with Chi-square and Student’s t-tests. Results: The study included 118 patients: 59 in the open surgery group (mean age 65.4 ± 11.1 years, 42.4% female) and 66 in the MIS group (mean age 61.4 ± 14.8 years, 30.5% female). Baseline characteristics were similar between groups (p > 0.05). The MIS group demonstrated significantly lower EBL (22.8 ± 28.1 vs. 135.0 ± 157.0cc, p = 0.0001) and OT (136.4 ± 68.8 vs. 201.17 ± 159.3 minutes). MIS patients also reported lower immediate postoperative NRS (2.1 ± 1.9 vs 5.2 ± 2.2, p = 0.0001) and improved ODI scores at 2 weeks, 3 months, and 1 year postoperatively (p 0.05). Conclusion: MIS decompression at L4-L5 is associated with significantly reduced blood loss, shorter operative times, and improved short-term and long-term patient-reported outcomes compared to conventional open approaches. While these findings provide preliminary evidence supporting the safety and efficacy of MIS techniques, further research is necessary to comprehensively evaluate their benefits and technical limitations in clinical practice. Panapol Varakornpipat 1 1 Department of Orthopedic, Faculty of Medicine, Naresuan University, Phitsanulok, Thailand Introduction: Early postoperative mobilization is an importance in spinal surgery that can reduce pulmonary complication and DVT but postoperative orthostatic intolerance may obstructive early recovery or lead to fainting, falls, and fracture. However, the prevalence of orthostatic intolerance has not been instituted after Minimally invasive lumbar interbody fusion. This study assessed the hemodynamic response to early mobilization after surgery ERAS program for Minimally invasive Lumbar Interbody Fusion. Material and Methods: Orthostatic intolerance and blood pressure response to sitting and standing were evaluated by used non-invasive hemodynamic monitor devices with a two-difference mobilization protocol at preoperative, 6, 12, 24, 48 hours after surgery in 30 patients undergoing single level Minimally invasive lumbar interbody fusion with an ERAS regimen. Two protocols were compared: (A) Patients supine, sit and suddenly stand. (B) Patients supine, sit and rest 30 seconds and stand. Haemoglobin, fluid balance, and opioid use were recorded. Systolic (SBP) and diastolic (DBP) arterial pressure, heart rate (HR), cardiac output (CO), stroke volume (SV) and oxygen saturation were measured. Results: In standard protocol (A), no demonstrated OI before surgery, whereas 8 (27%) patients had OI at 6 hours after surgery but no patients had symptoms of OI at 12, 24, 48 hours. OI was associated with significantly decreased orthostatic responses in SBP, DBP, SV, CO, MAP at 6 hours (p < 0.001). However, protocol B showed significantly decreased rate of OI at 6 hours compared protocol A (p < 0.001). Postoperative haemoglobin concentration and opioid dose was not associated OI. The Clinical outcomes were significantly improved in all patients. All patients were discharged to home on postoperative day 3 without complications or readmission. Conclusion: ERAS protocol showed incidence of OI often occur 6 hours after surgery. We suggest that patients should rest at sitting position at least 30 seconds before ambulation. ERAS in MI spine surgery provide early postoperative ambulation at 12 hours no demonstrated OI, reductions in length of stay, opioid use, complication, readmission and improve patient outcomes and functional recovery. Kunfeng Song 1 , Daniel Rosenthal 2 1 Third People's Hospital of Henan Province, Minimally Invasive Spine Surgery Center, ZhengZhou, China , 2 Hochtaunus-Kliniken, Minimally Invasive Spine Surgery Center, Bad Homburg, Germany Introduction: This study aims to systematically evaluate the safety and efficacy of Single-portal Coaxial Spine Endoscopy (SCSE) and Unilateral Biportal Endoscopy (UBE) in the treatment of Thoracic Spinal Stenosis (TSS). Material and Methods: A comprehensive search was conducted across several databases, including PubMed, EMBASE, Cochrane Library, and China National Knowledge Infrastructure (CNKI), to identify randomized controlled trials and retrospective studies that met the inclusion criteria. The comparison between SCSE and UBE focused on surgical time, intraoperative blood loss, complication rates, and clinical outcomes such as pain scores and functional scores. A meta-analysis was performed using random-effects or fixed-effects models to assess heterogeneity, and funnel plots and Egger's test were used to evaluate publication bias. Results: A total of 17 studies, involving 956 patients, were included in this meta-analysis. The results indicated that the SCSE group had significantly shorter surgical time and less intraoperative blood loss compared to the UBE group (p 0.05). Additionally, the complication rate in the SCSE group was lower than that in the UBE group, but the difference was not statistically significant (p > 0.05). Conclusion: Both SCSE and UBE demonstrate good safety and efficacy in the treatment of thoracic spinal stenosis. SCSE has advantages in terms of shorter surgical time and less intraoperative blood loss, making it suitable for patients sensitive to surgical trauma. Further high-quality randomized controlled trials are needed to confirm these findings. Amir Sharif 1,2 , Hamid Reza Abbasi 1 1 Inspired Spine , Spine Surgery, Burnsville, MN, United States , 2 Sana Regio Klinikum Pinneberg, Spine Surgery, Pinneberg, Germany Introduction: The standard treatment for lower back pain, interbody fusion, in an invasive procedure that requires stripping the muscles and soft tissue (TLIF). This leads to increased blood loss and a long recovery time. However, during the TLIF procedure, muscles are detached and denervated which may cause significant morbidity. To address these issues, minimally invasive (MI) TLIF was developed. While MI TLIF has been shown to decrease blood loss and complication rates relative to open TLIF, surgery times and long-term outcomes have been reported to be similar.Oblique posterior lateral lumbar fusion (OLLIF) is a surgical procedure designed for a minimally invasive spinal fusion. The OLLIF procedure allows for fusion of the lumbar spine through a single 10-15 mm incision, with faster surgery times and easier approach than previous technique. This procedure is normally performed for patients that require a spinal fusion with shorter recovery time required in a traditional spinal fusion surgery. Material and Methods: Anesthesia/surgery times and blood loss were recorded for all patients entered into the EMR database immediately after surgery. Because no suction is used in OLLIF procedures, blood loss for the OLLIF group was measured by weighing sponges and subtracting dry weight. To monetize the cost per minute for an operating room (OR) per case and for an average hospital day, a published reference for this amount was identified in the medical literature and adjusted by using consumer price index for medical costs. These values were reported both in aggregate and stratified based on the number of levels they had addressed at the time of their surgery (1, 2, 3 or 4).Mann-Whitney U-tests were utilized to test the null hypothesis that the OLLIF and TLIF groups have the same or identical mean distributions for age, BMI, blood loss, and the uncensored time duration variables. All data analyses were performed using SPSS. Results: Overal, across all surgeries studied, LOS for OLLIF surgeries was 58.5% of that seen with TLIF surgeries (3.1 vs. 5.3 days). The trend of shorter LOS for OLLIF surgeries remained consistent when surgeries were stratified and matched for the same number of levels involved (2.6 vs. 4.2 for one level, 3.2 vs. 5.8 for two levels, 3.2 vs. 4.3 for three levels, and 4.6 vs. 6.7 for four levels). Overall, when LOS was converted to inpatient operating costs of the hospital, the difference in cost of surgical admission was $6,701 for OLLIF vs. $11,583 for TLIF. Conclusion: The cost reductions and faster recovery times associated with the OLLIF procedure make it an appealing alternative to the traditional open fusions available for patient and insurance providers. The reduction in the use of these key hospital resources suggests that hospitals that are constrained by OR or hospital bed availability may be able to achieve greater throughput efficiency by increasing the overall percentage of patients receiving the OLLIF surgery. Songwut Sirivitmaitree 1 1 Bandung Crown Prince Hospital, Udon, Thailand Background: Biportal endoscopic spine surgery is a type of minimally invasive spine surgery that uses two small incisions to insert an endoscope and surgical instruments. Biportal endoscope provides various procedures, such as decompression, discectomy, and fusion. BE- TLIF is a surgical technique that combines the advantages of minimally invasive and endoscopic spine surgery. It is a type of spinal fusion surgery through a transforaminal approach that aims to stabilize the spine and relieve pain caused by various spinal disorders, such as degenerative disc disease, spondylolisthesis, and recurrent disc herniation. The advantage of BE- TLIF does not require a tubular retractor which may reduce muscle damage ,independent endoscopic and instrument ports were easily to contralateral decompression and reduce postoperative pain. Biportal endoscopic TLIF is a promising alternative to conventional open or minimally invasive TLIF, but it requires a learning curve and more studies to evaluate its long-term outcomes. Material and Method: Retrospective cohort study. This study included 72 patients with 81 fusion segments who underwent BE-TLIF between January 2020 and March 2022. All of the patients were observed at least a 12-month follow-up. We collected demographic data, total operation time and length of hospital stay. Clinical outcomes measures included visual analogue scale (VAS) scores for lower back pain and leg pain, Oswestry Disability Index (ODI),Plain film x-ray 1, 3, 6,12 months postoperatively and then every year thereafter. Computed tomography (CT) of the lumbar spine 6 and12 months postoperatively. The fusion rate was assessed using the Bridwell interbody fusion grading system. Cage subsidence was classified into no subsidence, no more than 2 mm, and more than 2 mm, Postoperative complications were also noted. Result: There were significant improvement in VAS for lower back pain from 6.3 ± 0.8 to 1.2 ± 0.5, VAS for leg pain from 5.8 ± 1.3 to 1.2 ± 0.4, ODI from 58.1 ± 11.9 to 13.4 ± 4.6. The p-values were all < 0.001. The average hospital stay was 4.7 ± 1.1 days. The CT studies available for 52 fusion segments. 6 months after surgery showed successful fusion (Bridwell grade I or grade II) in 33 segments (63.5%). 1 year after surgery showed successful fusion (Bridwell grade I or grade II) in 49 segments (94.2%). Significant cage subsidence of more than 2 mm was only noted in 46 segments (56.1%). Complications included 2 dural tear, 1 pedicle screws malposition, and 3 transient paresthesia, in which 1 patient required reoperations. Conclusion: BETLIF may have favorable clinical outcomes, high fusion rate and lower complication. BETLIF may be a good alternative treatment for lumbar spine disorder (stenosis, instability, and spondylolisthesis). Further studies with large samples and long-term follow-up are needed. Amir Sharif 1,2 , Hamid Reza Abbasi 1 1 Inspired Spine, Spine Surgery, Burnsville, MN, United States , 2 Sana Regio Klinikum Pinneberg, Spine Surgery, Pinneberg, Germany Introduction: Degenerative deformities of the spine have traditionally been treated with extensive open surgeries. However, these open procedures are associated with a high degree of surgical morbidity. In this study, we explore whether clinical improvement in patients with spinal deformities can be achieved using a new minimally invasive surgery (MIS) called oblique lateral lumbar interbody fusion (OLLIF). OLLIF is a MIS single surgeon procedure in which the disc is approached through Kambin's triangle. OLLIF can achieve correction of spinal deformities through careful cage placement. The purpose of this study is to establish the safety and efficacy of using OLLIF to correct spinal deformities and to collect early outcome data. Collected data includes perioperative outcomes, patient reported outcomes, and radiographic outcomes. Material and Methods: This study is a retrospective review of 37 OLLIF surgeries in 36 patients with symptomatic degenerative spinal deformity. Collected perioperative data included surgery time, blood loss, and hospital stay. Follow-up was conducted at least 150 days post surgery. We recorded complications and patient reported outcomes such as Oswestry Disability Index (ODI) and pain scale. Imaging was conducted pre- and post-surgery. Fusion rates and changes in Cobb angle were also measured. Results: A total of 37 surgeries that treated 100 vertebral levels were performed. For two and three level procedures, respectively, the mean blood loss was 83 and 178 ml, the average surgery time was 74 and 158 minutes and the average hospital stay was 2.6 and 3.3 days. The patients ambulated within 24 hours in all but two cases. The patients reported pain improvements on the ten-point pain scale from 8.3 to 3.7 (p < 0.001) and on the ODI from 53% to 32%. Cobb angles decreased from 16° to 9.3° (p < 0.001), amounting to 2.5° of correction per level of surgery. Detailed imaging was reviewed by independent radiologists for 24 cases and 100% interbody fusion was achieved along with 71% right posterolateral and 74% left posterolateral fusion. There were three cases of mild nerve irritation/neuropraxia and no infections. Conclusion: OLLIF is a safe and effective MIS technique to correct adult degenerative scoliosis. Unlike alternative procedures, OLLIF is technically less complex than comparable procedures and can safely be used from the thoracolumbar junction to S1. Atif Ali 1 , Muhammad Farrukh Bashir 1 1 Ghurki Trust Teaching Hospital Lahore, Orthopaedics and Spine Department, Lahore, Pakistan , Background: The management of degenerative lumbar disorders often involves transforaminal lumbar interbody fusion (TLIF). Minimally invasive TLIF (MIS-TLIF) and open TLIF (open-TLIF) with bilateral decompression are common techniques. This study retrospectively compares these approaches using data from 50 patients who underwent surgery at Ghurki Trust Teaching Hospital, Lahore. Methods: A total of 50 patients, 25 each undergoing MIS-TLIF and open-TLIF with bilateral decompression, were reviewed. All surgeries were performed in the last two years. Patient outcomes were evaluated based on pain relief (VAS), functional improvement (ODI), operative time, blood loss, length of hospital stay, and complication rates. Preoperative and postoperative data were analyzed for comparison. Results: The MIS-TLIF group demonstrated significantly lower intraoperative blood loss (average of 150 mL vs. 300 mL, p < 0.01) and shorter hospital stays (average of 3 days vs. 5 days, p < 0.05) compared to the open-TLIF group. Both groups achieved comparable improvements in pain relief and functional outcomes (VAS and ODI scores) at the 6-month follow-up. The incidence of complications was similar between the two groups, although the open-TLIF group had a slightly higher rate of wound infections (8% vs. 4%). Conclusions: MIS-TLIF with unilateral decompression offers advantages in terms of reduced blood loss and shorter recovery times compared to open-TLIF. However, both techniques are effective in improving pain and function. The choice of surgical approach should be individualized based on patient-specific factors and surgical goals. Luke Pearson 1 , Seung Lee 2 , Jared Weeks 1 , Emilio Supsupin 1 , Daryoush Tavanaiepour 1 , Kourosh Tavanaiepour 1 , Dunbar Alcindor 1 , Aboubakr Amer 1 , Vashisht Sekar 1 1 University of Florida Jacksonville, Jacksonville, United States , 2 Mayo Clinic Jacksonville, Jacksonville, United States Introduction: Lateral mass fractures of the axis (C2 vertebra) are common injuries, often resulting from high-energy trauma. While most are stable and managed conservatively, unstable fractures, particularly those associated with ligamentous injuries, require surgical intervention to prevent neurological compromise. This case report presents a 49-year-old female who underwent a minimally invasive C1-C2 posterior instrumented fusion for an unstable lateral mass fracture of C2 with posterior atlantoaxial membrane ligamentous injury. Material and Methods: The patient presented with neck pain and tenderness following a motor vehicle accident. Imaging studies, including CT scans and MRI, revealed a lateral mass fracture of C2 with associated posterior atlantoaxial membrane ligamentous injury, indicating an unstable fracture. Due to the instability and the patient’s symptoms, a minimally invasive C1-C2 posterior instrumented fusion was recommended. The surgery was performed under general anesthesia. A minimally invasive approach was employed, utilizing a midline incision and a muscle and fascia sparing technique to access the posterior elements of the C1 and C2 vertebrae. The fracture fragments were reduced and stabilized using a C1 lateral mass to C2 parsicle screw fixation system. Allogenic bone graft was placed to promote fusion. No surgical drain was necessary. Results: Post-operatively, the patient demonstrated significant pain relief and improved neck stability. The fracture fragments remained well-aligned and the bone graft showed evidence of fusion on follow-up imaging studies. The patient was able to return to her pre-injury activities without any neurological deficits. Conclusion: This case report illustrates the efficacy of minimally invasive C1-C2 posterior instrumented fusion in treating unstable fractures requiring stabilization. The minimally invasive approach allows for less tissue disruption, reduced blood loss, and a quicker recovery compared to traditional open techniques. This procedure effectively restores stability, reduces pain, and allows for a return to normal function. While further research is needed to evaluate long-term outcomes and optimize the technique, this case highlights the potential of minimally invasive C1-C2 posterior instrumented fusion as a safe and effective treatment option for this challenging condition. Amir Sharif 1,2 , Hamid Reza Abbasi 1 1 Inspired Spine, Spine Surgery, Burnsville, MN, United States , 2 Sana Regio Klinikum Pinneberg, Spine Surgery, Pinneberg, Germany Introduction: The oblique lateral lumbar interbody fusion (OLLIF) is a relatively new method of lumbar interbody fusion (LIF) that utilizes a trans-Kambin approach to the disc space. The OLLIF can be performed from T12-S1 in the majority of cases but is occasionally obstructed at the L5-S1 level by osteophytes, an overgrown facet joint and/or prominent sacral ala. Transfacet OLLIF (TF-OLLIF) is a novel method for LIF in which the disc space is accessed by drilling through hypertrophic facets with an OLLIF approach. We provide a proof-of-concept report on the TF-OLLIF surgical technique and report the clinical and perioperative outcomes for the first 29 patients who underwent this procedure. Material and Methods: This is a retrospective single surgeon cohort study of 29 patients with lumbar spinal stenosis (LSS) who underwent TF-OLLIF procedures between 8/2018 and 1/2021. The primary outcome was a change in the Oswestry Disability Index (ODI) one year after surgery. Secondary outcomes were surgery time, blood loss, hospital stay, and complications. The TF-OLLIF was performed using the approach and instrumentation of OLLIF. When osseous hypertrophy is reached during the approach, an 8 mm drill is used to drill through the obstructing bone with continuous neuromonitoring. Discectomy and interbody placement are performed with subsequent posterior pedicle screw fixation. Results: ODI improved from 49% pre-op to 31% at one-year follow-up. Estimated blood loss ranged from 97.6 ± 93.3 ml for one level TF-OLLIF to 146.2 ± 60.3 ml for a 3+ level TF-OLLIF. Operative time ranged from 57.4 ± 19.5 minutes for a one-level TF-OLLIF to 102.9 ± 27.8 minutes for a 3+ level TF-OLLIF. The average length of hospital stay (LOS) was 0.4 ± 0.8 days for one-level TF-OLLIF and 1.6 ± 1.9 days for 3+ level TF-OLLIF. Complications included five cases of nerve root irritation immediately postoperatively, with three of these patients still reporting mild L5 distribution numbness at the last follow-up, which was not clinically limiting. Conclusion: The first 29 cases of TF-OLLIF demonstrated that it is a safe method of interbody fusion that yields good clinical results. This is an important development for practitioners of OLLIF as it enables interbody placement with OLLIF instruments and approach even for challenging L5-S1 levels without compromising surgical outcomes. Amir Sharif 1,2 , Hamid Reza Abbasi 2 1 Sana Regio Klinikum Pinneberg, Spine Surgery, Pinneberg, Germany , 2 Inspired Spine, Spine Surgery, Burnsville, MN, United States Introduction: This study presents findings from an investigation into the correlation of neuromonitoring techniques in minimally invasive lumbar fusions and their open counterparts regarding acceptable thresholds for screw stimulation. The threshold for acceptable stimulation value for open surgery has been established. The study compared acceptable thresholds for open pedicle screws where there is more connection between the screw and the soft tissue. Material and Methods: The neuromonitoring data of 17 patients who underwent oblique lateral lumbar interbody fusion (OLLIF) procedures between September 2023 to May 2024 were reviewed. Neuromonitoring was conducted throughout surgeries, recording stimulation thresholds for pedicle screws insulated and uninsulated, to simulate the environment of a screw during open and minimally invasive surgery respectively. Patients' BMI was also collected for potential correlation analysis. Results: Results indicate a discernible correlation between stimulation thresholds in open and minimally invasive surgeries, but no definitive correlation with BMI due to sample size limitations. Though a significant correlation between the two stimulating styles is apparent, there is a good correlation to suggest what threshold should determine a standard stimulation threshold for minimally invasive surgeries. Conclusion: The study emphasizes the need for refined neuromonitoring strategies in minimally invasive spinal fusion (MISF) surgeries to ensure patient safety and surgical effectiveness. Further research with larger cohorts is recommended to establish optimized protocols that have a clearly defined amplitude for MISF thresholds. Marisa Pérez Solís 1 , Andrea Sinagra 1 1 University of Buenos Aires, Postgraduate, Neurosurgery, Buenos Aires, Argentina Introduction: Kambin’s triangle is the key to different approaches to the intervertebral disc, including transforaminal lumbar interbody fusion (TLIF) and endoscopic approaches. The classical description as a foramen is no longer enough and requires a new 3D vision in which this anatomical structure should be described as a corridor. The object of this work is to redefine the anatomic boundaries which constitute this fundamental surgical corridor and propose the new term Kambin’s conduct. Material and Methods: We evaluated the morphology of the intervertebral conduct in 15 cadavers in cervical, dorsal and lumbar regions and we compared them to 90 radiological studies. Results: The redefinition of anatomical structures defining the transforaminal corridor should lead to the improvement of transforaminal approaches and to lessen the lesions of the nerve roots emerging from this corridor. Apart from the x and the y coordinates, we should add a third dimension for depth, which incorporates the superior articular process. These three coordinates’ geometric form describe an actual conduct. Conclusion: The new approaches to the intervertebral disc have led to the revision of a classic anatomical structure such as Kambin’s triangle. The 3D vision allows us to redefine its limits, showing that it is actually a conduct and not a triangle, which is a fundamental concept for those surgeons using transforaminal approaches, reducing complications and lesions of the nerve roots. Andrea Sinagra 1 , Marisa Pérez Solís 1 1 University of Buenos Aires, Postgraduate, Neurosurgery, Buenos Aires, Argentina Introduction: Facet joint disease is the cause of many cases of lumbar pain. To treat LBP originating from the FJs, different types of therapies have been developed, being Radiofrequency denervation the most extended treatment. We propose endoscopic denervation as a safe treatment which provides longer term pain relief and describe technique and complications. Material and Methods: Endoscopic denervation was fulfilled in 25 patients suffering facet joint disease in whom conservative treatment had failed after 3 months, between March 2022 and April 2023. The procedure was done under sedation in OR. Results: Endoscopic FJ denervation provided a longer term pain reduction when compared to other percutaneous techniques and results were measured with VAS. It allowed changing the classic target, medial dorsal branch, to the joint capsule, which allows longer period of relief. Conclusion: Endoscopic FJ denervation offers the possibility of addressing not only the dorsal medium ramus but also the surrounding tissue, yealding a longer term pain reduction compared to percutaneous techniques. We propose the treatment of the joint capsule as new target in treatment of FJ pain. Liliana Silva 1 , Jose Sauri 2 , Eduardo Callejas 2 1 IMSS, Puebla, Mexico , 2 Centro Medico ABC, Ciudad de México, Mexico Introduction: Endoscopic surgery is indicated for intervertebral disk herniation, spinal stenosis, infective spondylodiscitis, spondylolisthesis, and even revision surgery. In Mexico, very few surgeons are trained in full-endoscopic techniques. Objective: We describe our experience with the first one-hundred cases of endoscopic surgery in the lumbar spine performed in our institution. Methods: We revised the medical files of the first one-hundred cases of endoscopic surgery in the lumbar performed at the ABC Medical Center. We included demographic information; perioperative data; lumbar and leg pain visual analog scale (VAS) and Oswestry score at preoperative 1, 3, 6, and 12 months; and complications. We used central dispersion statistics and student t-tests for comparisons. Results: The first case was performed on 9th May 2017. A total of 55 patients were male, and 45 patients were female; the mean age was 54. The most frequent diagnosis was disk herniation. Singlelevel surgery was done in 92% of the cases, most frequently in L5-S1 (49%), with an interlaminar approach in 55% of the cases. We had a 16% rate of complications. Axial and radicular pain and Oswestry scores in the preoperative and postoperative periods had statistically significant differences (p < 0.01). All patients were operated using intraoperative neurophysiologic monitoring (IOM). Conclusion: Endoscopy is a safe, reproducible, and successful surgical technique that has comparable results with the current gold standard. Our results compare to those in the international series. Marco Gonzalez-Gomez 1 1 Hospital Clínica Nova, Neurosurgery, Spine Surgery, San Nicolas de los Garza, Mexico Introduction: Spinal canal stenosis is a pathological condition characterized by the abnormal narrowing of the spinal canal, resulting in the compression of neural structures, including the spinal cord and nerve roots. This condition can occur in any segment of the spine, but it is more common in the lumbar and cervical regions. The etiology of spinal stenosis is multifactorial, including congenital, degenerative, traumatic, and iatrogenic factors. As the global population ages, the prevalence of spinal stenosis has significantly increased, becoming a major cause of chronic pain and disability in older adults. Symptoms range from localized pain and radiculopathy to neurogenic claudication and progressive neurological deficits, severely impacting the quality of life of patients. The search for less invasive techniques led to the development of minimally invasive laminectomy in the late 20th century. This technique was designed to reduce surgical trauma by minimizing incision size and soft tissue disruption. Advances in endoscopic and microsurgical technology have been fundamental to the development of this technique. Material and Methods: A retrospective, cross-sectional, descriptive, and analytical study was conducted on patients over 64 years old with grade 1 spondylolisthesis who underwent minimally invasive laminectomy and “over the top” decompression between 2019 and 2023 at the Neuro Surgery and Spine Surgery Service of Hospital Clínica Nova in Monterrey, Nuevo León, México. The patients included in the study were treated according to neurosurgical practice guidelines from January 2019 to December 2023. Clinical-surgical and radiological care will remain in the clinical and radiological archive of the institution. The institution's radiological archive was utilized to measure the magnitude of spondylolisthesis in millimeters pre- and post-operatively, in order to quantitatively document the relationship between the surgical procedure and the persistence or increase of the condition. Patient follow-up regarding intra- and post-hospital management and care was reviewed in the clinical records. Inclusion Criteria: Patients over 64 years old with grade 1 spondylolisthesis and spinal canal stenosis requiring surgical management. Exclusion Criteria. • Patients aged 64 years or younger. • Spinal canal stenosis that does not require surgical management. • Patients without spondylolisthesis. • Patients with grade 2 or higher spondylolisthesis. Results: Fifty-two patients underwent minimally invasive laminectomy and “over the top” decompression at Hospital Clínica Nova from January 2019 to December 2023. With an average age of 69 years and a standard deviation of ± 4 years, there were 30 male patients and 22 female patients. A prevalence of 31% for systemic arterial hypertension and 15.7% for type 2 diabetes mellitus was found. Among the treated segments, 37 patients had the L4-5 segment (71.1%) and 15 patients had the L5-S1 segment (28.9%). The average surgical time was 84 minutes ± 15 minutes, with intraoperative bleeding of 50 ml ± 10 ml and a hospital stay of 36 hours ± 6 hours. An improvement in average pain scores was documented, with the numerical pain scale. Conclusion: Clinical and Radiological satisfactory results. Recovery of daily activities. A good alternative to traditional surgery. Steep learning curve. Daniel Navarro Arriaga 1 , Michael Dittmar 1 , Francisco Cruz López 1 , Alejandro Tejera 1 , Francisco Javier Sánchez García 1 , Jorge De Haro Estrada 1 , Jared Muñoz López 1 1 Re-espalda A.C., Spine Surgery, Zapopan, Jalisco, Mexico Introduction: Lumbar stenosis is a degenerative condition that affects a large number of people. This condition is characterized by narrowing of the spinal canal in the lumbar region, which puts pressure on the spinal cord and nerve roots, causing symptoms such as lower back pain, muscle weakness, and limitation in the ability to walk or stand. Advances in endoscopic spine surgery generate new opportunities to minimize tissue damage in this type of surgery. Comparison between both approaches is scarce, and concerns about safety and benefits remain under investigation. The main objective was to compare the clinical results of endoscopic versus tubular decompression in lumbar stenosis. Material and Methods: PRISMA guidelines were followed to conduct a systematic review in MEDLINE, Embase and Cochrane databases of studies published from 2019-2023. The following search was used: (((“lumbar stenosis” OR “lumbar spinal stenosis”) AND (“Endoscopy” OR “Endoscopic”)) OR ((“MI” OR “Minimally invasive”) AND (“MISS TLIF” OR “Minimal Invasive Spinal Surgery with Transforaminal Lumbar Interbody Fusion))). Two pools of patients were formed, those with tubular and endoscopic surgery, to compare clinical characteristics, functional results, complications, days of hospitalization, and bleeding. The chi square test and student's t were used to study the differences in the analyzed variables. Results: 25 articles were found, 11 unrelated to the topic were eliminated. Patients were grouped according to the technique, tubular (T) or endoscopic (E). The average follow-up was 16.2 ± 4 months. The T group had 930 patients, and the E group had 1030. The age was 57.9 ± 11 and 63.4 ± 10 years, for the T and E groups, respectively. The proportion of women was 61% for tubular and 52% endoscopic. The average intraoperative hemorrhage was greater by 128 ml in group T (p 0.20). The average hospitalization was greater by 2.6 days in group T (p 0.38). The frequency of complications was 4.5% for technique E, compared to 9.6% for group T (p 0.02). Success of surgery measured through clinical improvement and mobility in the first year was 94% for group T, and 100% for E (p 0.03). Conclusion: As found in this analysis, the endoscopic approach improves the benefits even more than the tubular approach. An ultra-minimally invasive approach reduces trauma and complications, but according to the studies reviewed it has a steep learning curve. Planning and training are critical variables in this approach. The main finding of the present analysis is that both tubular and endoscopic decompression provide significant clinical improvement and high success rates at a minimum follow-up of 12 months. Dong-Wuk Son 1 1 Pusan National University Yangsan Hospital, Neurosurgery, Pusan, South Korea Introduction: Spinal fusion at the L5/S1 level presents unique challenges due to high mechanical loading. The Oblique Lateral Interbody Fusion (OLIF) approach offers advantages over traditional posterior methods, notably in the use of larger, taller, and more lordotic cages. However, vascular anatomy at L5/S1 can limit OLIF's feasibility and poses risks of vessel injury. This presentation shares our experiences with vascular damage in the L5/S1 OLIF approach. Material and Methods: From April 2018 to May 2024, we reviewed 948 OLIF patient cases, focusing on L5/S1 level interventions, excluding posterior approaches. Data were collected on cases requiring vascular repair or surgeon assistance due to major bleeding. We detail the causes and management of vascular injuries and postoperative complications. Results: Of the OLIF patients, 119 involved L5/S1. This group included 75 with a between bifurcation approach, 26 with a pre-psoas approach, and 18 with posterior fusion. Vascular injury prevention strategies were used in three cases. Complications occurred in four cases, three managed by the surgeon and one requiring a vascular specialist. Two cases experienced intraoperative hypotension, but there were no mortalities or postoperative lower extremity venous circulation problems. Conclusion: Vascular injury rates at L5/S1 were higher than other lumbar level (L2-5). Most bleeding events were surgeon-manageable. Reducing vascular injury risk involves thorough preoperative imaging review and careful orientation during surgery. Sealing techniques for hemostasis were effective, and in case of failure, maintaining visibility and using clipping strategies are recommended. Mauricio Cardoso 1 , Rodrigo Cruzeiro 1 , Andre Castilho 1 , Pedro Torres 1 1 Hospital Unimed, Belo Horizonte, Brazil Introduction: Lumbar disc herniation during pregnancy is a rare but challenging condition, affecting approximately 1 in 10,000 pregnant women. Surgical management in this population requires careful consideration of potential risks to both mother and fetus. Methods: A 32-year-old woman at 22 weeks and 4 days of gestation presented with a right-sided L5-S1 lumbar disc herniation. The patient reported a two-month history of pain, with significant worsening in the past week. Previous treatments, including morphine, tramadol, and weekly acupuncture, provided minimal relief. She experienced severe pain (VAS 9/10) in the right gluteal region, posterior right thigh, and right calf, without motor or sensory deficits. After multidisciplinary evaluation, endoscopic spine surgery was performed. The patient was positioned prone with thoracic and pelvic support, leaving the abdomen free. An obstetrician monitored fetal heart rate (FHR) throughout the procedure using a portable device. The surgery lasted 1 hour and 56 minutes, with only 12 fluoroscopic images taken to confirm endoscope positioning. FHR ranged between 127 and 131 bpm during the procedure. The patient's postoperative course was uneventful. At the 15-day follow-up, she reported complete pain resolution (VAS 0/10). The pregnancy continued without complications, resulting in a full-term delivery. Conclusion: This case demonstrates that endoscopic surgery for lumbar disc herniation can be safely performed during the second trimester of pregnancy when indicated. Key factors contributing to the successful outcome included: 1. Multidisciplinary approach involving orthopedic surgery and obstetrics. 2. Use of minimally invasive technique. 3. Careful patient positioning. 4. Continuous fetal monitoring. 5. Limited radiation exposure (12 fluoroscopic images). The procedure's safety was further evidenced by stable fetal heart rates and the uncomplicated progression of the pregnancy to term. In selected cases and with appropriate precautions, endoscopic surgery for lumbar disc herniation may be a safe and effective option during the second trimester of pregnancy. This approach minimizes risks associated with open surgery, although general anesthesia was used in this case. The successful outcome highlights the importance of a multidisciplinary approach and careful perioperative management. However, further studies are needed to establish definitive management protocols for these challenging cases. Senol Jadik 1 1 Kuwait Hospital, Neurosurgery, Kuwait City, Kuwait Introduction: Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) has gained prominence as a preferred surgical technique for managing degenerative spine conditions, such as spondylolisthesis and disc degeneration. This technique aims to provide effective decompression, precise reduction of olisthesis, and optimal cage insertion while minimizing tissue disruption. Additionally, the integration of robotic assistance in pedicle screw placement has further enhanced surgical precision and patient outcomes. Materials and Methods: A retrospective analysis was conducted on over 300 cases of MIS TLIF. The surgical technique focused on meticulous nerve root decompression, olisthesis reduction, and appropriate space creation for cage insertion. In a subset of cases, a robotic tool was utilized to aid in pedicle screw placement, aiming to improve accuracy and reduce intraoperative radiation exposure. Patient outcomes, including ambulation time, postoperative pain, infection rates, and hospital stay duration, were recorded and compared to conventional open approaches. Results: Patients treated with MIS TLIF exhibited several advantages over traditional open lumbar fusion techniques. Key outcomes included faster ambulation, reduced postoperative pain, lower rates of infection, and shorter hospital stays, leading to earlier discharges. The robotic-assisted pedicle screw placement significantly improved the accuracy of screw positioning, while reducing radiation exposure and operative time. These improvements were associated with enhanced safety and a more rapid overall recovery process. Conclusion: MIS TLIF, combined with robotic-assisted pedicle screw placement, offers distinct advantages in the surgical management of degenerative spine pathologies. The technique's minimally invasive nature leads to quicker recovery, reduced postoperative complications, and shorter hospital stays. The integration of robotic technology further enhances the accuracy and safety of pedicle screw placement, while minimizing radiation exposure. These findings support the adoption of MIS TLIF as a preferred approach for lumbar interbody fusion in appropriate patient populations, particularly when the precision of robotic assistance can be utilized. Peter Hudak 1 , Kristian Varga 1 , Martin Sedliak 1 , Milan Liska 1 , Jan Kozak 1 , Benedikt Trnovec 2 1 Department of Neurosurgery, University Hospital in Bratislava - Ružinov, Bratislava, Slovakia, 2 Neurosurgery Department, Bory Hospital, Bratislava, Slovakia Most hangman’s fractures are treated conservatively. If surgery is indicated, an anterior approach using a C2/C3 graft and plate fusion is usually preferred. Direct transpedicular osteosynthesis of hangman’s fracture according to Judet is a “physiological operation” that does not cause fusion and creates anatomical conditions. Dorsal approach is frequently rejected because of the high risk of spinal cord damage or vertebral artery tear. Computed tomographic (CT) guidance is used to ensure safe and exact introduction of two screws from the posterior approach. The procedure also allows for accurate intraoperative control of instrument and implant placement, screw tightening, fracture reduction and anchoring of the screw tip in the contralateral cortex, using repeated CT scans. This new aspect of the surgical procedure ensures highly accurate screw placement and minimal risks, and fully achieves the “physiological” internal fixation. Bernardo Aramuni Mariano Aramuni Mariano 1 , Gleidson Guilherme Carvalho da Silva 2 , Matheus Ramos Lopes 2 , Antonio Campos 1 , Vinicius Moreira Vasconcellos 1 , Orlandil Donato Rocha Donato Rocha 1 , Raphael David Pimenta de Carvalho 1 , Athos Guimarães Soares 1 , Pedro Nilo Vilaça e Silva 1 , Giovanni Inácio Batista 1 , Paulo Henrique Lopes Bezerra 1 , Rafael Vitor Silva Gaioso dos Santos 1 , José Queiroz de Deus e Silva 1 , Fábio Santana Carvalho 1 , Gustavo Silvério Laguna 1 , Audrey Beatriz Santos Araújo 1 , Mariana Torres Alcântara 1 , Pedro Henrique Santos Ribeiro Henrique Santos Ribeiro 1 , Lina Márcia de Araújo Herval 1 , João Pedro Oliveira Rezende 2 1 Odilon Behrens Municipal Hospital, Neurosurgery Department, Belo Horizonte, Brazil , 2 Federal University of Ouro Preto, Ouro Preto, Brazil Introduction: Spinal canal stenosis can progress with compression of both the spinal cord (myelopathy) and the nerve roots (radiculopathy) and develops insidiously, leading to progressive spinal cord dysfunction. The Nurick classification system is used to assess the patient's functionality and quantify the progression of myelopathy. Traditionally, open anterior cervical discectomy & fusion (ACDF) and posterior laminectomy and laminoplasty are the most commonly used techniques for decompressing the cervical spine. However, due to the great anatomical disruption, they cause complications and post-operative morbidity, which justifies a high demand for new, less invasive techniques. In this sense, a new option is biportal endoscopic spinal surgery (UBE), a technique adapted from uniportal endoscopy for thoracolumbar segments. This is based on the opening of two unilateral paravertebral accesses in the cervical region that allow endoscopic exploration and decompression with minimal laminectomy and facetectomy. Its use allows for a better field of vision for the surgeon, less iatrogenic damage to the patient and post-operative complications, shorter recovery time and a more aesthetic scar. Therefore, the aim of this paper is to present the results of a series of 7 cases in which UBE was used for spinal decompression. Material and Methods: These were cases received at a Brazilian hospital, referred to the hospital's neurosurgery department and then assessed using a full history and physical examination and classified according to the Nurick scale. The patients were referred for cervical decompression surgery. The medical records were registered in the hospital's system and all patients signed an informed consent form. Results: Seven patients with an average age of 54 years complaining of cervicobrachialgia, myasthenia, limb paresis and incontinence were enrolled. The average chronology of symptoms was 56 months. Of these patients, 1 had Nurick's Grade I, 2 Grade II, 1 Grade IV and 3 Grade V. They then underwent magnetic resonance imaging which revealed 2 patients with unisegmental involvement (C5-C6) and 4 with multisegmental involvement (C3/T1). Among these, the following diagnoses were made: narrow cervical canal, progressive cervical myelopathy, joint spondylosis, spinal canal stenosis and radiculopathy with foraminal stenosis. They were then referred for spinal decompression surgery via biportal cervical endoscopy with an average surgical time of 3.5 hours. After the procedure, CT scans showed effective decompression in all 7 cases. However, 1 patient remained with tetraparesis and speech deterioration, 1 with dysparesis, 1 with lower limb hyperreflexia and 1 with right hemiparesis. Despite this, the Nurick score improved or was maintained in all cases and none of the patients needed to be converted to open surgery or reoperation. Conclusion: As demonstrated in our experiences, the use of cervical UBE was effective in achieving results similar to those of open decompression and avoiding its associated complications. Brandon Morales Pineda 1,2 , Alfonso Nuñez Salazar 2 , Humberto Diaz castillo 2 , Manuel Sanchez Prado 2 1 Angeles Valle Oriente, Columna, San Pedro, Nuevo Leon, Mexico, 2 Angeles Valle Oriente, San Pedro, Nuevo Leon, Mexico Introduction: Lumbar fusion is a treatment alternative for patients with degenerative or traumatic lumbar spine pathology. However, the rate of revision surgeries in these procedures has been increasing, with foraminal stenosis being the most frequent cause of revision, from 25 to 29%. Patients with failed lumbar spine surgery usually require revision surgery, but the success rate decreases with each surgical reintervention, while the complication rate increases due to fibrosis and post-surgical anatomical changes, causing most frequently dural injuries or nerve injuries. This is why the use of minimally invasive technology becomes an acceptable therapeutic option, reducing the risk of injuries and presenting considerable pain relief at one-year follow-up. Material and Methods: A case series was conducted of patients with persistence of radicular symptoms and narrow lumbar canal with a history of more than one lumbar spine surgery treated with selective endoscopic neurological decompression using an extraforaminal approach on the affected side. It is a descriptive, retrospective study, with comparison of pre-surgical and post-surgical clinical variables evaluated 4 weeks after surgery. The variables were: Daniels scale of pelvic limbs, sensitivity, pre- and postoperative pain scale, Oswestry disability index; and post-operative CT evaluations. Results: The study included 3 patients (2 F, 1 M), with an average age of 67.3 years, the average preoperative VAS was 8 with a preoperative disability index of 52% (severe disability), with a Daniels scale in the affected segment of 2/5 and dysesthesia of the affected segment. The postoperative results after one month of evaluation were VAS 4 in the affected leg, strength 4/5 of the affected segment, they reported persistence of dysesthesia with less intensity. In the postoperative tomographic measurements, the average height of the foramen was 14 mm with a length of 16.5 mm. Among the complications, a dural injury was reported and one of the patients developed radiculopathy on the contralateral side to the one operated on. Conclusion: Selective neurological decompression with endoscopy using an extraforaminal approach is a reliable technique, which showed a significant improvement in radicular symptoms, low back pain, and improved sensitivity and strength of the affected segment.

Melanie Schindler 1 , Nike Walter 1 , Jan Reinhard 2 , Stefano Pagano 2 , Dominik Szymski 1 , Volker Alt 1 , Markus Rupp 1 , Siegmund Lang 1 1 University Hospital Regensburg, Trauma Surgery, Regensburg, Germany , 2 University Hospital Regensburg, Orthopedic Surgery, Bad Abbach, Germany Background: Pyogenic vertebral osteomyelitis (VO) represents a clinical challenge and is linked to substantial morbidity and mortality. This study aimed to examine mortality as well as potential risk factors contributing to in-hospital mortality among patients with VO. Methods: This retrospective analysis involved patients receiving treatment for VO at University Regensburg in Germany from January 1, 2000, to December 3, 2020. The criteria were: Onset of symptoms occurring after one month of hospitalization without signs of vertebral osteomyelitis upon admission, hospital admission within six months prior to symptom onset, outpatient diagnostic or therapeutic interventions within six months prior to symptom onset (long-term use of a central venous catheter, arteriovenous fistula for hemodialysis, invasive intravascular techniques, urological, gynecological, or gastrointestinal procedures, and skin procedures), spondylodiscitis cases not meeting any of the above criteria were classified as community-acquired vertebral osteomyelitis (CAVO). It included in-hospital mortality rate, comorbidities and pathogens. Patients were identified using ICD-10 diagnosis codes: M46.2, M46.3, M46.4, and M46.5. Kaplan–Meier probability plots and odds ratios (OR) for mortality were calculated. Results: So, a total of 155 patients, included 88 men and 67 women, who were treated for VO, were collected in the study between 2010 and 2020 at a University Hospital in Germany. The average age of these patients was 66.7 ± 12.4 (26-93) years. The mean CCI stood at 4.1 ± 3, while the mean ACCI was recorded at 2.1 ± 1. The average length of hospital stay for these patients was 36.5 ± 36.3 (1-343) days. Out of the total cohort of 155 patients with VO, 53 patients (34.1%) died during a mean follow-up time of 87.8 ± 70.8 months. The overall mortality was 17.2% at one year, 19.9% at two years and 28.3% at five years. Patients with congestive heart failure (p = 0.005), renal disease (p < 0.001), symptoms of paraplegia (p = 0.029), and sepsis (p = 0.006) demonstrated significantly higher overall mortality rates. In 56.1% of cases, pathogens were identified, with Staphylococcus aureus (S. aureus) and other unidentified pathogens being the most common. Renal disease (OR 1.85) and congestive heart failure (OR 1.52) were identified as significant risk factors. Conclusion: Early assessment of the specific risk factors for each patient may prove beneficial in the management and treatment of VO to reduce the risk of mortality. These findings demonstrate the importance of close monitoring of VO patients with underlying chronic organ disease and early identification and treatment of sepsis. Prioritizing identification of the exact pathogens and antibiotic sensitivity testing can improve outcomes for patients in this high-risk group. Adnene Benammou 1,2 , Souha Bennour 1,2 , Seddik Akremi 1,2 , Yassine Grissa 1,2 , Mehdi Bellil 1,2 , Mohamed Ben Salah 1,2 1 University Tunis el Manar, Faculty of Medecine of Tunis, Tunis, Tunisia , 2 Charles Nicolle Hospital, Orthopedic Surgery Department, Tunis, Tunisia Introduction: The spine is the third location when it comes to tuberculosis and while chemotherapy has proven its effectiveness alone its associated with spinal kyphotic deformity. Non-surgical management has long been used but it’s usually insufficient to prevent the deformity. Percutaneous pedicle screw fixation is an alternative minimally invasive surgical technique to prevent complications related to spinal instability. Material and Methods: A retrospective descriptive monocentric study was lead between 2018 and 2020 including patients having benefited from percutaneous pedicle screw fixation for a tuberculosis spondylodiscitis in the thoracolumbar spine with no neurological impairment. Clinical parameters collected were age and past medical history, symptoms that lead to diagnosis and the duration of treatment before surgery . Functional parameters were mainly the Visual analogical scale (VAS) and the Core outcome measure index (COMI) and Oswestry Disability scale (ODI) . Radiological parameters noted on MRI were the signs of spondylodiscitis and the level of injury . Standard x rays were used to measure the regional kyphosis pre and postoperatively and the loss of correction at last follow up. A CT scan was used to evaluate the fusion rates. Early and delayed complications were noted. Results: Thirty patients were included in the study with a mean age of 50.2 years and gender ration of 1.14. The mean duration of TB chemotherapy before surgery was of 20 days. The T10-T11 and T11-T12 were the most frequently observed levels of injury. 22 patients benefited from a short segment fixation. 70% of patients were able to ambulate day one following surgery. The mean VAS went from 8 to 5 post operatively and the COMI from 63.8 to 26.6%. The mean cobb angle was measured at 8 preoperatively and 7.18 at last follow up. Loss of correction was estimated at 2.13 at last follow up. 25 patients benefited from a CT scan to evaluate the fusion with complete fusion being obtained in 56% of cases. Mechanical failure with rod breakage was noted in 3 patients and operative site infection was noted in 3 cases managed successfully with irrigation and debridement. Conclusion: While surgical management of TB related spondylodiscitis is associated with good radiological results Peroperative and postoperative morbidity is relatively high. Percutaneous pedicle screw fixation comes as a minimally invasive effective technique to allow adequate healing. In absence of neurological impairment and major deformity (≤ 10°) percutaneous screw fixation is associated with good radiological results and significant pain relieve. However, such advantages come with the radiation exposure that decreases with the learning curve. Adnene Benammou 1,2 , Habib Sanaa 1,2 , Seddik Akremi 1,2 , Souha Bennour 1,2 , Mehdi Bellil 1,2 , Mohamed Ben Salah 1,2 1 University Tunis el Manar, Faculty of Medecine of Tunis, Tunis, Tunisia , 2 Charles Nicolle Hospital, Orthopedic Surgery Department, Tunis, Tunisia Introduction: Cervical spondylodiscitis is a rare. In contrast with other locations of spinal infections, possible severely septic and neurological complications make cervical spondylodiscitis a life-threatening disease in which urgent treatment is mandatory. The aim of our study is to evaluate the clinical and radiological results of surgical treatment of cervical spondylodiscitis. Material and Methods: This is a retrospective study of patients treated for Cervical spondylodiscitis in the orthopedic surgery and traumatology department at Charles Nicolle Hospital between January 2019 and January 2022. Results: Our study included 18 patients with an average age of 58 years. Average follow-up was 1 year. The most affected stage was C6-C7 in 40% of cases. The most isolated germ was Staphylococcus aureus . Epidural abscess was present in 70% of cases.16 patients underwent corpectomy, debridement and anterior fusion. 2 patients had posterior laminectomy and fusion. 30% of patients had neurological signs preoperatively. Improvement in neurological signs was noted in 16 patients and no neurological deterioration were noted. VAS score decreased from 8/10 preoperatively to 5/10 immediately postoperatively and to 3/10 at 6 months postoperatively. Radiologically, bony fusion was achieved in all patients and the cervical lordosis angle at the final follow-up recorded a mean improvement of 5°. Conclusion: Spondylodiscitis of the cervical spine is a rare but serious disease due to the narrow anatomic dimensions of the cervical spinal canal. Operative treatment of spondylodiscitis seems to be the preferable therapeutic option. In fact, surgical treatment has a diagnostic interest by directly removing the disc and addressing it to laboratory examination, a neurological interest by relieving nerve decompression, a septic interest by debridement to accelerate healing and bony fusion, and a mechanical interest by restoring spinal statics. Also, it has shown a good outcome with partial or complete resolution of neurologic symptoms. However, this treatment is still a controversial issue when it comes to the placement of implants in a septic environment. This problem is generally resolved by using titanium implants and a 15-day of antibiotics pre-operatively. Adnene Benammou 1,2 , Mokhtar Abderrahim 1,2 , Seddik Akremi 1,2 , Habib Sanaa 1,2 , Mehdi Bellil 1,2 , Mohamed Ben Salah 1,2 1 University Tunis el Manar, Faculty of Medecine of Tunis, Tunis, Tunisia , 2 Charles Nicolle Hospital, Orthopedic Surgery Department, Tunis, Tunisia Introduction: Spinal tuberculosis is the most prevalent and the most aggressive of all the musculoskeletal tuberculosis localizations. Its subacute course is associated with delayed diagnosis causing devastating consequences, neurological signs and spinal deformities. Symptoms can be misleading and mimic other pathology such as degenerative disk disease and disc herniation. We report the case of a young male who presented and was treated for a lumbar disc herniation that appeared to be a spinal tuberculosis. Material and Methods: We report the case of a 28-year-old male who was diagnosed as lumbar disc herniation but a spinal tuberculosis was discovered when operating the patient. Results: We report the case of a 28-year-old male with no previous medical history, who presented with right L5-type sciatica resistant to medical treatment. Physical examination and biology were unremarkable. MRI findings concluded a lumbar disc herniation at the L4-L5 level. Surgical treatment with herniectomie was decided. When operating the patient, at the time of opening the Posterior longitudinal ligament, there was pus outlet. We realized multiple sampling and saline irrigation with a wound closure. On the immediate postoperative course, the patient noticed an improvement in the symptomatology. Laboratory results of PCR tuberculosis of the sampling came positive and confirmed the diagnosis of spinal tuberculosis. The patient was treated with anti-tuberculosis treatment and immobilization. At 2 months postoperative, the patient presented with collection on the surgery site. MRI showed a multilevel spinal tuberculosis with a posterior collection. The patient was treated with a second surgery with debridement, sampling and irrigation with saline. The sampling from the second surgery revealed a positive culture for Pseudomonas aeruginosa. The patient received an adapted antibiotics for the second germ with the treatment of the tuberculosis. At 12 months follow-up, the patient was pain free and resumed his work and his activities. Conclusion: Spinal tuberculosis can be a misleading diagnosis mimicking multiples diagnosis such as disc herniation and degenerative disk disease. Surgeons must be aware of this entity especially in endemic countries. Thorough examination of the MRI must be realized. Bacteriological and histological sampling are mandatory at the slightest doubt. Mutaleeb Shobode 1 , Gbadebo Ibraheem 2 , lukman Ajiboye 3 , Misbahu Ahmad 4 , Oladapo Ekundayo 5 , Mohammed Kabir Abubakar 6 , Mohammed Salihu 7 , John Onuminya 8 1 Nationwide Children's Hospital, Department of Orthopaedics, Clinical research, Columbus, Ohio, United States , 2 University of Ilorin Teaching Hospital, Department of Orthopaedics, Kwara, Nigeria , 3 Usmanu Dan Fodiyo University Sokoto, Department of Surgery, Sokoto, Nigeria , 4 Aminu Kano Teaching Hospital, Department of Surgery, Kano, Nigeria , 5 University of Alberta, Division of Orthopaedics, Edmonton, Nigeria , 6 Aminu Kano Teaching Hospital, Department of Orthopaedics, Kano, Nigeria , 7 University of Abuja Teaching Hospital Gwagwalada, Department of Orthopaedics, Abuja, Nigeria , 8 Irrhua Specialist Hospital, Deaprtment of Orthopaedics, Edo, Nigeria Introduction: Surgical treatment Tuberculous Spondylitis is indicated in the presence of worsening neurology, unacceptable kyphotic deformity and mechanical instability. Anterior decompression/debridement and replacement with healthy autologous fibular graft restores column stability, corrects deformity, encourages fusion and reduces rate of subsidence due to similar Young’s modulus. Objective: To highlight the pathology and provide a preliminary report on the outcome of surgical treatment of TB Spondylitis using Tri-fibular Strut Graft. Materials and Methods: Twenty-seven patients with Gulhane Askeri Tıp Akademisi (GATA) type II and III spinal tuberculosis had anterior surgical debridement and replacement with either a mesh cage or autologous trifibular strut graft (ATSG). Of these patients, 17 had ATSG while 10 had mesh cage replacement. All the patients were evaluated with Full blood count and erythrocyte sedimentation rate, plain radiographs, and MRI scan. ASIA- IS was used to assess neurological recovery. Plain radiograph and CT scan were used to assess graft union. Results: They were aged 12 to 64 years. Standalone ATSG was used in 13 patients in the thoracic spine while 4 patients had a 540 0 fusion in the lumbar spine. There was similar neurological recovery in both groups of patients. Average duration of surgery was 90 minutes in the mesh cage group (7 thoracic and 3 lumbar procedures done as standalone) while the ATSG was 120 minutes for thoracic and 4 hours for the lumbar combined procedures. Blood loss was also significantly higher in the ATSG group. Conclusions: The use of autologous trifibular strut graft is safe, versatile and the graft is readily available. It affords good mechanical stability and promotes bony fusion Keywords: Trifibular Strut Graft, GATA, Tuberculous Spondylitis, ASIA-IS Julius Gerstmeyer 1,2,3 , August Avantaggio 3 , Clifford Pierre 2,3 , Neel Patel 2,3 , Donald Davis 2,3 , Bryan Anderson 2,3 , Periklis Godolias 4 , Thomas Schildhauer 1 , Amir Abdul-Jabbar 2,3 , Rod Oskouian 2,3 , Jens Chapman 2,3 1 BG University Hospital Bergmannsheil, Department of General and Trauma Surgery, Bochum, Germany , 2 Swedish Neuroscience Institute, Seattle, United States , 3 Seattle Science Foundation, Seattle, United States , 4 St. Josef Hospital Essen-Werden, Department of Orthopedics and Trauma Surgery, Essen, Germany Objective: Spondylodiscitis (SD) poses an increasing challenge to healthcare providers by its insidious onset and diverse clinical manifestations, concurrent with an aging population, immunocompromising conditions, substance abuse, diabetes mellitus, renal diseases and enhanced diagnostic testing. Overall mortality remains relatively high, up to 7.3%, despite advancements in diagnostics and treatment. Past studies have struggled to differentiate leading causes for mortality. With this study we want to utilize the large data group available through the National Inpatient Sample (NIS) to assess the in-hospital mortality in patients with SD in different age-groups and to identify risk factors. Methods: Utilizing the 2020 NIS, Healthcare Utilization Project (HCUP) adults (> 18 years) were screened using the primary diagnosis of SD by ICD-10 Code (M46.2x, M46.3x and M46.4x). Demographic information, admission details, clinical data, comorbidities, and surgical treatment were extracted using the Clinical Classifications Software Refined (CSSR) categories. Age was categorized into 3 groups (< 65 years; ≥ 65-79: ≥ 80). The primary outcome was in-hospital mortality, with multivariable logistic regression analysis used to identify independent risk factors. Results: In total 3,975 patients met our inclusion criteria resulting with an in-hospital mortality rate of 0.9%. The mortality group was significantly older (70.86 years to 58.74 years compared to the survival group) with elective admission being more common (p ≤ 0.001) with a similar sex distribution. Patients ages 65-79 were more common in the mortality group. Overall fourteen comorbidities differed significantly between the two groups. Chronic diseases were more common in the mortality group, whereas alcohol and substance abuse were more prevalent in the survival group. Age, especially patients < 65 years, elective admission status, paralysis and pneumonia were identified as independent risk factors for mortality. Conclusion: Management of SD remains complex. Our study revealed a lower rate of in-hospital mortality and length of stay than previous studies. Elective admission status was the strongest predictor of mortality, highlighting the benefits of early diagnosis and treatment. Patients > 65 years, especially octogenarians, were identified to be particular at risk. Risk factors for mortality in SD might differ to those causative SD, identifying potential further research. Prabhat Agrawal 1 1 AIIMS Patna, Orthopaedics, Patna, India Introduction: Spinal tuberculosis accounts for approximately 1% of cases in patient with active pulmonary tuberculosis and typically involves 2-3 contiguous vertebra. Non contiguous multifocal spinal tuberculosis with extensive involvement of all spinal region is very rare and only few cases are reported which are treated surgically. Here we present an interesting case which involves all the spinal region and was treated surgically in single stage. Material and Method: A 26 year old male presented with non functional power in all limb, unable to sit even with support and severe pain in neck, back and pelvic area. He was diagnosed with pulmonary TB and on anti tubercular therapy for last 2 months. He his bedridden for last 2 months. MRI shows extensive involvement of all spinal region with paravertebral, retropharyngeal abscess, cervical kyphosis. NCCT shows gross destruction of multiple cervical vertebra and near total destruction of thoraco-lumbar and lumbo- sacral region. Keeping in mind early total care we decided to decompress theca sac and reconstruction of spinal column in single sitting so that he can be nursed properly. Through anterior retropharyngeal approach cervical was fixed from C5 to T2 with corpectomy of C6 and C7 vertebra and then through posterior approach lateral mass fixation was done from C4 to T2. As his T-L region and LS region was completely destroyed and there was no obvious theca sac compression at these level we planned to by- pass these region by fixing thoracic region to pelvis by utilising dual iliac screws and sub muscular rod. Patient was kept in ICU for a day and was discharged after 5 days on Anti tubercular drugs and guided exercises. He showed remarkable recovery post operatively and he is now fully functional after a year of follow up. Discussion/Result: Multifocal spinal tuberculosis patients are more prone to neurological involvement because of double crush neural phenomenon and by fulminating disease process. Goal of management is to provide stable spinal column and proper theca sac decompression and chemotherapy so that these patients can be out of bed as soon as possible. Very few cases have been reported for such an extensive disease process and most of them had opted for staged surgery. Here as our patient is young who can tolerate long duration surgery and was bed ridden for last 3 months so we opted for single staged surgery and have provided holistic care to the patient. Dual iliac screws are generally utilised for adult spinal deformity to stabilise lumbo-pelvic fixation and in sacral tumour cases here we used in a case of infectious disease which is not reported in literature before. Conclusion: Astute clinical examination, imaging of whole spine, proper anti tubercular therapy based on RT PCR, assessment of requirement of patient, keeping in hand all the possible implants is crux in the management of such extensive disease. David Campos Pacheco 1 , Miguel Fuentes Rivera 1 , Amado González Moga 1 1 Instituto de Seguridad Social del Estado de México y Municipios, Cirugía de Columna, Traumatología y Ortopedia, Ecatepec de Morelos, Mexico Objective: To present a complex clinical case of post-surgical infection after lumbar instrumentation, describing the pharmacological and surgical interventions necessary for the resolution of the infectious process, and highlighting the critical decisions made from admission to discharge of the patient. Methods: The clinical history of a patient undergoing 360 PLIF L4-L5 arthrodesis was reviewed, who developed a post-surgical infection that required multiple interventions. The timeline included hardware removal surgeries, surgical clean-ups, debridements, and VAC repositioning. Cultures were positive for Staphylococcus aureus and Escherichia coli. In addition, various antibiotics were administered: Ceftriaxone, Amikacin, Clindamycin, Cephalexin, Vancomycin, Metronidazole, and Ertapenem. The dates of each intervention and the periods of antibiotic administration were recorded. Results: The patient was initially admitted on January 29, 2024 for arthrodesis and discharged on January 31. He was readmitted on April 5, 2024 due to signs of infection. Between March 14 and April 29, 2024, the patient underwent nine additional surgeries, including hardware removal, transpedicular instrumentation, multiple surgical clean-ups, and debridements with VAC placement and repositioning. Initial cultures showed Staphylococcus aureus infection, for which Vancomycin and Metronidazole were administered. Subsequent cultures revealed Escherichia coli infection, treated with Ertapenem. Finally, on April 29, 2024, the surgical wound was closed and the patient was discharged on May 3, 2024. Conclusions: The management of post-surgical infections in lumbar instrumentation, especially in the presence of pathogens such as Staphylococcus aureus and Escherichia coli, requires a multidisciplinary approach, involving multiple surgical interventions and an antibiotic regimen adjusted according to culture results and clinical response. In this case, the combination of repeated debridements, management with VAC systems, and specific antibiotic therapy resulted in the resolution of the infectious process and the recovery of the patient. These findings highlight the importance of close follow-up and rapid response to post-surgical complications to achieve favorable outcomes in patients with severe infections after spinal surgery. Keywords: Post-surgical infection, lumbar instrumentation, comprehensive management, pharmacological treatment, surgical treatment, Staphylococcus aureus, Escherichia coli, surgical cleaning, microbiological cultures, rehospitalization. Weijian Zhu 1 , Wei Xiong 1 1 Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China Introduction: Aspergillus fumigatus spondylitis is a rare fungal spondylitis that often occurs in immunocompromised patients. Material and Methods: We report the clinical presentation, diagnosis, and prognosis of a patient with Aspergillus fumigatus spondylitis. We conducted a literature review and retrospective case series to determine clinical characteristics, treatment strategy, and outcomes of Aspergillus fumigatus spondylitis. Results: A 63-year-old male presented to the clinic with low back pain for over one month, followed by painful numbness in both lower extremities. There was no specific past medical history. Inflammatory indicators were slightly high, and T1W sequences showed localized low-signal shadows, with the discs and vertebral rims poorly visualized. Fluid sequences showed diffuse high-signal at T12-L1, with a reduced disc height, and the disc morphology was still intact. After three weeks of antibiotic treatment, the patient showed no improvement in symptoms and underwent posterior approach lesion debridement and autologous iliac bone grafting with pedicle screw internal fixation. Following the surgery, fungal culture and Next-generation Sequencing (NGS) tests were conducted on the vertebral body and intervertebral disc tissues. The results indicated Aspergillus fumigatus. Consequently, Voriconazole was administered for ten weeks, resulting in improved symptoms and the patient's discharge from the hospital. In immunocompetent patients with nonspecific clinical signs, Aspergillus fumigatus spondylitis should also be considered. Aspergillus spondylitis often leads to the formation of an annular high signal on fluid sequences around intervertebral discs. It also results in the development of large paraspinal abscesses. Prompt diagnosis and treatment can improve the patient’s prognosis. Conclusion: This report summarizes the distinctive MRI features of Aspergillus spondylitis. This is the first report of this sign in similar patients. Bastian Stemmer 1 1 University Hospital Augsburg, Department of Neurosurgery, Augsburg, Germany Introduction: The aim of this study was to identify potential risk factors for surgical site infections after spinal surgery. Methods: A retrospective analysis of all patients who suffered a postoperative infection after spinal surgery in our hospital between April 2023 and November 2023 was performed. Potential risk factors were identified and analyzed. Results: 24 consecutive patients were identified (50% male, 50% female). Degenerative spine disease was the most common diagnosis (50%) followed by tumor (33.3%). As potential risk factors could be identified Diabetes mellitus (42%), renal insufficiency (17%), rheumatism (12.5%), art. Hypertension (25%), obesity (75%), reduced mobility (37.5%), dural lesion (17%). In 67% of cases, implants were used. As the causative agent Staph. aureus (25%) could be detected followed by Staph. epidermidis (12.5%) and Corynebacterium striatum (12.5%). Conclusion: We could identify several risk factors for surgical site infections after spine surgery. On average, more than 2 risk factors applied per case. Zaccaria Richard 1 , Kenny Hagar 1 , Bernd Wegener 1 , Christof Birkenmaier 1 , Trobisch Per 2 , Randal Betz 3 1 LMU Klinikum München, Traumatology, Orthopedic Surgery, Munich, Germany , 2 Eifelklinik St. Brigida, Zentrum für Orthopädische Chirurgie, Zentrum für Wirbelsäulenchirurgie, Simmerath, Germany , 3 Institute for Spine & Scoliosis, Lawrenceville, NJ, United States Background: Posterior correction and fusion using pedicle screws and rods is the standard treatment for progressive adolescent idiopathic scoliosis (AIS). The Vertebral Body Tethering (VBT) method was developed to achieve scoliosis correction while maintaining mobility and avoiding the drawbacks of rigid systems. VBT, based on growth modulation principles, is relatively new with limited experience and no validated algorithms for implant-associated complications such as infections. Case Presentation: A 15-year-old girl with idiopathic thoracolumbar scoliosis of Lenke type 6 underwent flexible anterior correction using Vertebral Body Tethering (VBT) from T10 to L3. Following an uncomplicated course, she was discharged from inpatient care. Two months later, she presented with progressive left-sided flank pain. Initial diagnostics showed no significant findings, but later, a suspected incisional hernia was confirmed and repaired laparoscopically. Subsequent wound issues led to the detection of Staphylococcus aureus and a paravertebral abscess. Treatment included vacuum-assisted closure (VAC) and a staged approach to remove and later re-instrument the implant. After removal of the osteosynthesis material and infection control, re-instrumentation from T10 to L4 was necessary due to the altered curve. Postoperative X-rays showed successful correction, and the patient was discharged after an uncomplicated course. Discussion: This case illustrates the complex challenges and limited experience with VBT, particularly concerning implant-associated infections. Various treatment options have their advantages and drawbacks. Prolonged antibiotic therapy allows for implant retention but poses significant risks, while removing the implant risks correction loss and increased morbidity. In this case, the staged removal and re-instrumentation approach successfully controlled the infection and restored postoperative stability. Conclusion: Treating peri-implant infections in VBT is complex and not adequately covered by existing guidelines. The case underscores the need for further research and development of specific treatment recommendations for VBT-associated infections. The successful outcome following a flexible, individualized treatment approach highlights the importance of a well-thought-out management strategy for these rare complications. Adhi Prayoga Ida Bagus 1 1 Bangkalan General Hospital, Orthopaedy, Kota Surabaya, Indonesia Introduction: World Health Organization (WHO) assessed that 845,000 cases of tuberculosis (TB) and 200,000 new cases of leprosy are registered annually worldwide. Both diseases share a similar pathogenesis cascade caused by intracellular Gram-positive aerobic acid-fast bacilli that induces host’s immune response and ended with chronic granulomatous infections. Many case reports and cohorts studies have been published reporting the frequent correlation between TB and leprosy with multiple clinical presentation regarding the affected organs, but the simultaneous infection of spinal tuberculosis and leprosy within one host has rarely been reported. We hereby report two patients with spinal tuberculosis and leprosy co-infection. Material and Methods: Thirty-three patients from March 2018 – June 2024 that visited Bangkalan General Hospital – East Java were initially evaluated and has been confirmed with spinal tuberculosis with various severity of back pain, neurologic deficit and pathologic fracture of spinal columns. Twenty-seven patients were treated surgically whereas five patients with milder symptoms were treated conservatively using braces. During follow-up of treatment of four drug regimens of antituberculosis therapy (ATT), two patients showed clinical sign of leprosy and later enrolled in this study. Results: The first patient come from surgically treated group and the second patient is from conservative treatment group. Both of the patients with initial TB workup showed a positive interferon-gamma release assays (IGRAs), negative sputum acid fast bacilli (AFB) with chest radiography (CXR) showed a mild perihilar infiltrate, giving suspicion for active TB despite minimal respiratory symptoms. Throughout the therapy they reported a reddish skin patch around their face and body followed by numbness around their extremity. Further Fite-Faraco staining showed granular acid-fast bacilli in macrophages and nerves. The treatment converted to rifampicin, isoniazid, pyrazinamide, and ethambutol, with the addition of dapsone once diagnosis of leprosy was confirmed. Conclusion: The simultaneous infection between TB and leprosy and its impacts on the incidence of each other remain a matter of debate. Dual mycobacterial infections of TB and leprosy are not uncommon yet infrequently reported. Environmental and genetic factors including the immunological milieu of the host seem to influence the paradoxical susceptibility and the development of both TB and leprosy. It is considered that other foci of infection may induces the exacerbated inflammatory response. Correct and timely treatment for both infections must be established to prevent poor outcomes. Saadi Chedi 1 , Meddeb Mehdi 1 , Ben Mohamed Oussema 1 , Mzid Ahmed 1 , Khalil Habboubi 1 , Mondher Mestiri 1 1 Kassab Institute of Orthopedics, Mannouba, Orthopedic Surgery “Adultes “, Manouba, Tunisia Introduction: Spinal echinococcosis is a rare but severe complication of echinococcosis, characterized by the formation of hydatid cysts in the spinal column. This case study chronicles the prolonged and complex journey of a patient with spinal echinococcosis over more than twenty years. Material and Methods: NK, a 25-year-old female from Gafsa, initially diagnosed with multi-visceral echinococcosis at age 3, was treated with Albendazole for renal, hepatic, and peritoneal hydatid cysts. Subsequent developments included a psoas muscle cyst and recurrence of hepatic and renal cysts by age 6, and in 2004, the emergence of debilitating back pain due to an intra-canalicular cyst at D12-L1, leading to a surgical intervention involving laminectomy and hemilaminectomy. The patient experienced post-operative complications including lower limb weakness and recurrent dorsalgia, which led to further surgical procedures in 2007 and 2019. In 2019, the patient presented with severe back pain, claudication, paraparesis, and significant spinal deformity due to recurrent echinococcosis at D11, leading to extensive spinal destruction and paravertebral extension. Emergency surgery included vertebrectomy from T10 to T12, laminectomy, corporectomy of the destroyed D11 vertebra, and hydatid cyst removal. Post-operatively, the patient demonstrated notable improvement with resolution of back pain and urinary symptoms. Results: The multi-stage surgical approach led to a significant correction of spinal deformity, alleviation of back pain, and resolution of urinary and sphincter dysfunction. The patient, previously confined to bed and unable to continue her studies, was successfully rehabilitated and currently undergoing physical therapy. Conclusion: Spinal echinococcosis presents as a challenging and often insidious condition with significant risks for spinal cord and nerve root compression. Early and aggressive medical and surgical management is critical, involving comprehensive decompression and stabilization to mitigate long-term complications. Prevention and health education remain vital in managing and reducing the incidence of such chronic conditions. Tae Sik Goh 1,2 , Jung Sub Lee 1,2 , Yoon Jae Cho 2 , Hansol Kim 2 1 Pusan National University, Orthopaedic Surgery, Busan, South Korea, 2 Pusan National University Hospital, Busan, South Korea Introduction: Surgical site infection (SSI) following spine surgery is a critical complication impacting patient recovery. Traditional serum inflammatory markers like C-reactive protein (CRP) and white blood cell count (WBCC) are commonly used to detect SSI. However, the need for earlier diagnostic tools has prompted the exploration of alternative markers. This study investigates the diagnostic potential of platelet count and mean platelet volume ratio as immediate postoperative indicators of SSI, offering a potentially quicker assessment of infection risk than CRP and WBCC. Material and Methods: In this retrospective study, we analyzed patients who underwent lumbar spine surgery from January 2013 to December 2023. The study comprised 32 patients requiring escalated postoperative care, matched in a 1:3 ratio with 96 control patients based on age, sex, and fusion levels. Parameters measured included CRP, ESR, CRP/albumin ratio, neutrophil to lymphocyte ratio, immature granulocyte count, and platelet count to mean platelet volume ratio, taken immediately after surgery and on POD3. Operation time and estimated blood loss (EBL) were also compared. The study aimed to evaluate the sensitivity, specificity, and likelihood ratios of these biomarkers in predicting SSI. Results: Significant elevations in CRP, ESR, and CRP/albumin ratio were observed on POD3 in the patient group, indicating an inflammatory response linked to SSI. Notably, the platelet count to mean platelet volume ratio was the only marker that showed a significant increase immediately post-surgery in the patient group, suggesting its effectiveness as an early infection indicator. Conclusion: The platelet count to mean platelet volume ratio stands out as a more immediate and effective marker for early detection of SSI following lumbar spine surgery, compared to traditional markers like CRP. This early detection capability could enable quicker clinical interventions, potentially improving patient outcomes and reducing the incidence of postoperative complications. The study highlights the importance of incorporating this platelet index into postoperative monitoring protocols for spine surgery patients. Muhammad Jawad Saleem 1 , Shahzaib Baloch 1 1 Orthopedic Spine Institute, Lahore, Pakistan Objective: To Study outcome of Transforaminal lumber interbody debridement and fusion (TLIDF) with posterior instrumentation and Spinal fusion (PISF) in cases of infective spondylodiscitis. Method: Our study comprised of 150 patients who were diagnosed with Lumbar Discitis who underwent TLIDF using Vancomycin and Tobramycin plus bone graft substitute and PEEK cage with PISF from 2017 to 2020 at Orthopaedic Spine Institute. All patients received 6 weeks of IV antibiotics followed by 6 weeks of oral antibiotics and minimum follow up of 18 months were included in study. There functional Outcomes were assessed using the Oswestry Disability Index (ODI), Visual Analog Scale (VAS), and Kirkaldy-Willis function outcome criteria at preoperative and then at 18months post-surgery. Serial CRP and ESR were taken as infection markers. Serial Radiographs were taken to assess Fusion and sagittal alignment of fusion segments. Results: Majority of our patient population were males with 63% patients. Most of our preop ODI scores came under crippling category and our 18 months follow-up scores came down under moderate level of disability. The mean Visual Analogue score came down to 2 from a preoperative mean score of 7, at 18months follow-up. The Kirkaldy-Willis functional outcome criteria was categorized to good at 18 months from poor at pre-op. Intraoperative Culture was positive in 75 percent of cases. Methicillin Resistant Staph Aureus (MRSA) was most common Pathogen. In one case there was deep wound infection and implant was removed at 3 months. 90 percent was the fusion rate in infective segments. Lordotic angle of lumber spine and infective segment was improved 15 degree and 10 degree respectively. Conclusion: It was concluded TLIDF in infective spondylodiscitis provides good clinical outcome, infection eradication with good fusion rate and improved sagittal balance post-operatively. Keywords: Transforaminal Lumber Interbody Debridement Fusion(TLIDF), Posterior Instrumentation Spinal Fusion (PISF), Methicillin Resistant Staph Aureus (MRSA). Majdi Ben Romdhane 1 , Bedoui Mootez 1 , Ahmed Msakni 1 , Tejouri Achref 1 , Charfi Mahdi 1 , Rafik Elafrem 2 1 Internal Security Forces Hospital, La Marsa, Tunisia Introduction: Lumbar sciatica often presents diagnostic and therapeutic challenges, especially in elderly patients with comorbid conditions such as diabetes and Parkinson's disease. These comorbidities can obscure the clinical picture and complicate management. The rapid worsening of symptoms, including motor and sphincter disturbances, underscores the necessity for urgent evaluation to differentiate between benign conditions and serious diagnoses like spondylodiscitis. Spondylodiscitis is an infectious inflammation of the intervertebral disc and adjacent vertebrae, which can present similarly to disc herniation on imaging studies but requires a different treatment approach. We present a case of a 69-year-old woman whose initial diagnosis of lumbar sciatica due to disc herniation was revised to spondylodiscitis following further investigations. Case Report: A 69-year-old woman with a history of diabetes and Parkinson's disease, presented with diffuse lumbar sciatica and a poorly defined spinal syndrome. Despite increasing the dosage of Levodopa and Benserarazide, her symptoms failed to improve. Over time, her condition deteriorated, resulting in urinary disturbances, severe difficulty walking, and significant motor deficits (ASIA score 38/50 and 108/112). The MRI initially revealed a paramedian disc herniation at L1-L2 on the right with 20 mm caudal migration, along with a central disc herniation at L5-S1. However, given the lack of improvement and the development of new symptoms, a re-evaluation of the MRI was undertaken. This review, coupled with the clinical picture and laboratory findings, led to the diagnosis of disc-vertebral spondylodiscitis. The biological assessment revealed a markedly elevated CRP level of 271 mg/L, and cultures from both urine and sputum identified Klebsiella pneumoniae . Empirical antibiotic therapy with cefotaxime was promptly initiated and later refined to cefotime based on the antibiogram results. Discussion: Spondylodiscitis, though rare, is a serious condition that can present with symptoms similar to those of disc herniation, especially in elderly or immunocompromised patients. This case highlights the critical need for re-evaluation of the initial diagnosis when faced with atypical clinical signs and unresponsive symptoms. The discrepancy between the initial imaging results and the final diagnosis underscores the importance of considering spondylodiscitis in differential diagnoses for patients with severe and worsening lumbar sciatica. The patient's significant improvement following the initiation of targeted antibiotic therapy emphasizes the necessity for prompt and accurate diagnosis to prevent potential neurological and functional complications. Conclusion: This case illustrates the need for rigorous diagnostic re-evaluation in elderly patients presenting with lumbar sciatica, particularly those with complex comorbidities. While spondylodiscitis is rare, it should be considered in the differential diagnosis. Early initiation of appropriate antibiotic therapy can lead to significant functional recovery and prevent severe complications. Ahmad Kareem Almekkawi 1 , Dylan Glaser 2 , Brandon Edelbach 3 , James P. Caruso 4 , Ghewa Sbaiti 5 , Salah Aoun 6 , Carlos Bagley 1 1 Saint Luke's Hospital, Neurosurgery, Kansas City, United States , 2 University of Missoure - Kansas City, School of Medicine , Kansas City, United States , 3 Loma Linda University, School of Medicine, Loma Linda, United States , 4 NYU Langone, Orthopedic Surgery, New York, United States , 5 UT Southwestern, Pharmacy, Dallas, United States , 6 UT Southwestern, Neurosurgery, Dallas, United States Introduction: Recent literature has demonstrated that surgical management of primary osteomyelitis may provide more benefit to patients. This study aimed to systematically review the literature on surgical management of primary osteomyelitis discitis and perform a meta-analysis comparing the efficacy of different surgical approaches used to treat this pathology. Material and Methods: A comprehensive literature review was performed. Studies that compared conservative treatment with surgical management of primary osteomyelitis and reported details of the type of surgical procedure were included. A random-effects model was used to determine differences in rates of clinical deterioration, re-operation, and length of hospital stay. Differences in positive clinical outcomes between the operative approach and procedure type were determined with ANOVA. Results: Thirty-eight studies involving 1,885 patients were included in this study. A total of 917 (48.6%) of patients were managed conservatively and 968 (58.4%) received surgical intervention. There were no significant differences in rates of clinical deterioration, rates of re-operation, or duration of hospital stay between the two groups. Stratification of the data according to operative approach or procedure type revealed no significant differences when assessing clinical outcomes. Stratification of the combined operative approach and procedure type revealed significant differences in rates of clinical improvement (p = 0.33). Anterior decompression and debridement were associated with significantly greater rates of improved clinical outcomes when compared to combined anterior and posterior decompression and debridement with instrumentation (p = 0.47) and anterior instrumentation with decompression and debridement (p = 0.38). Conclusion: There were no significant differences in rates of clinical deterioration, re-operation, or duration of hospital stay between patients who were managed conservatively or received surgical intervention. When assessing the surgical approach and procedure type, anterior decompression and debridement may be more advantageous when compared to anterior and posterior decompression and debridement with instrumentation and anterior instrumentation with decompression and debridement. However, the choice of surgical approach and procedure is multifactorial and may require more than just decompression and debridement due to vertebral column instability. Majdi Ben Romdhane 1 , Bedoui Mootez 1 , Ben Theyer Maher 1 , Majdi Sghaier 1 , Lafrem Rafik 1 1 Internal Security Hospital, La Marsa, Tunisia Introduction: Tuberculosis is an endemic disease in Tunisia. Pott disease, also known as tuberculosis spondylitis is the most common osteoarticular localization of tuberculosis and has the potential to cause serious morbidity, including permanent neurologic complications and spinal deformities. Material and Methods: It is a retrospective study about 19 tuberculosis spondylitis. There was a predilection for male patients with a sex ratio 2/1. The mean age was 49 years. All patients had undergone a complete physical examination and plain radiographs. Computed tomography (CT) and Magnetic resonance imaging (MRI) were done in respectively 12 cases and 11 cases. Pulmonary radiographs were normal in 17 cases. Decreased range of motion was present in 13 cases. Dysphagia and hoarseness due to a retropharyngeal abscess were present in one case. Results: Spinal deformities were present in 5 cases: 1 torticolis, 1 dorsal kyphosis and 3 kyphosis of the lumbar spine. Neurologic abnormalities occurred in 36% of cases and included spinal cord compression with paraplegia in 2 cases, paresis and impaired sensation in2 cases, nerve root pain in a 2 cases, and cauda equina syndrome in one case. Cervical spine was affected in 1 case, thoracic spine in 3 cases, thoracolumbar hinge in 2 cases, lumbar spine in 11 cases and sacrum in 2 cases. Cervical spine tuberculosis is a less common presentation but is potentially more serious because severe neurologic complications are more likely. Although the thoracic and lumbar spinal segments are nearly equally affected in persons with Pott disease, the thoracic spine is frequently reported as the most common site of involvement. Together, these segments make up 80-90% of spinal tuberculosis site. Conclusion: Every spinal segment has its particular clinical features in the diagnosis of Pott disease. Its diagnosis should be investigated if strong clinical suspicion exists, even if suggestive pulmonary radiology findings are absent. Ahmad Kareem Almekkawi 1 , Brandon Edelbach 2 , Dylan Glaser 3 , James P. Caruso 4 , Ghewa Sbaiti 5 , Salah Aoun 6 , Carlos Bagley 1 1 Saint Luke's Hospital, Neurosurgery, Kansas City, United States , 2 Loma Linda University, School of Medicine, Loma Linda, United States , 3 University of Missouri - Kansas City, School of Medicine, Kansas City, United States , 4 NYU Langone, Orthopedic Surgery, New York, United States , 5 UT Southwestern, Pharmacy, Dallas, United States , 6 UT Southwestern, Neurosurgery, Dallas, United States Introduction: Primary osteomyelitis discitis is a challenging condition with varying management strategies. This study aimed to systematically review the literature on management of primary osteomyelitis discitis and perform a network meta-analysis comparing the efficacy of different antibiotic treatment durations. Methods: A comprehensive literature search was conducted. Studies reporting outcomes for treatment of primary osteomyelitis discitis were included. A random-effects network meta-analysis was performed comparing antibiotic treatment durations of < 4 weeks, 4-8 weeks, 8-12 weeks, and 12-16 weeks. The surface under the cumulative ranking curve (SUCRA) was used to rank treatment effectiveness. Results: Sixty-three articles with 4,233 patients were included. Staphylococcus aureus was the most common causative agent (57.6%). The 4-8 week antibiotic duration ranked highest across fixed-effect and random-effects models (SUCRA 0.8207 and 0.8343). The 12-16 week duration ranked highest in the fixed-effect model (SUCRA 0.8460) but dropped substantially in the random-effects model (SUCRA 0.3067). The < 4 week duration showed mixed results. The 8-12 week duration consistently ranked lowest. No statistically significant differences were found between durations for symptomatic relief. Conclusion: Antibiotic therapy for 4-8 weeks may provide the optimal balance of efficacy and treatment duration for most patients with primary osteomyelitis discitis. However, treatment should be individualized based on clinical response. Further prospective studies are needed to clarify optimal management strategies for this complex condition. Shahid Ali 1 , Muhammad Jawad Saleem 1 , Abubakar Atiq Durrani 1 1 Orthopedic Spine Institute, Spine Surgery, Orthopedic Sugery, Lahore, Pakistan Introduction: Spinal tuberculosis is not only a challenge to developing world but developed countries also dealing with immunocompromised patients presenting with Spinal Tuberculosis. Here we are presenting our data regarding outcome of Transforaminal interbody debridement and fusion (TIDF) with posterior instrumentation and Spinal fusion (PISF) in cases of Thoracolumbar Tuberculus spondylodiscitis. Material and Methods: Our study comprised of 100 patients who were diagnosed with Thoracolumbar Discitis who underwent TIDF using Vancomycin and Tobramycin plus bone graft substitute and PEEK cage/Pyramish cage with PISF from Feb 2019 to Jan 2022 at Orthopaedic Spine Institute. All patients received 12 weeks of Intensive Regimen of Antitubercular Therapy (ATT) and 15 months of maintenance therapy with two drug regimen. Patients were followed up for a period of 18months. All patients had preoperative MRI, Xray, TLC, CRP and ESR. There functional Outcomes were assessed using the Oswestry Disability Index (ODI), Visual Analog Scale (VAS), and Kirkaldy-Willis function outcome criteria at preoperative and then at 18months post-surgery. Serial CRP and ESR were taken as infection markers. Serial Radiographs were taken to assess Fusion and sagittal alignment of fusion segments while MRI was taken at 9 months and 18months post surgery. Results: Majority of our patient population were males with 55% patients. Most of our preop ODI scores came under crippling category and our 18 months follow-up scores came down under minimal level of disability. The mean Visual Analogue score came down to 2 ± 0.7 from a preoperative mean score of 8 ± 0.5, at 18months follow-up. The Kirkaldy-Willis functional outcome criteria was categorized to good at 18 months from poor at pre-op. Intraoperative Culture was positive in 30 percent of cases while Histopathology was diagnostic in all cases. Two patients had proximal screw loosening. Interbody Fusion was achieved in 95% patients at an average of 10months. Correction in sagittal parameters achieved at Lumbar lordosis and thoracic kyphosis at operated levels remained within ± 5 degrees while over all thoracic and lumbar sagittal balance improved in long term. Conclusion: It was concluded TIDF with PISF in Thoracolumbar Tuburculus spondylodiscitis provides good clinical outcome, infection eradication with good fusion rate and improved sagittal balance post-operatively. Keywords: Transforaminal Interbody Debridement Fusion (TIDF), Posterior Instrumentation Spinal Fusion (PISF ). Laksh Agrawal 1 , Shrinivas Prabhu 1 , Anil Khandekar 1 , Nilesh Vishwakarma 1 1 MGM Hospital, Kamothe, Orthopaedics, Navi Mumbai, India Introduction: Pyogenic spondylitis and tuberculous spondylitis are common causes of spinal infection. It is essential to make a microbiological diagnosis as treating tubercular (TB) vs pyogenic causes are starkly different. Since a definitive diagnosis with a biopsy of the affected spine is often not possible in resource-constrained settings, there is a heavy reliance on clinical presentation and radiological findings. However, this is challenging as all infections significantly overlap in their radiological features. Staphylococcus aureus is the most frequent cause of spinal infections, accounting for more than 50% of cases. In contrast, Mycobacterium tuberculosis accounted for < 25% of the cases. Here, we present a rare case of mixed tubercular and pyogenic spondylodiscitis. Material and Methods: A 30-year-old male patient visited a local hospital with severe lower back ache, bilateral positive SLRT, and normal power. On investigating in the form of radiographs and magnetic resonance imaging, he was diagnosed with L3-4 spondylodiscitis, prompting further investigation in the form of a CT guided biopsy. Samples from the biopsy presented positive for TB GeneXpert and TB MGIT. As per protocol, patient was stated on CAT-1 Antitubercular drugs at the same hospital. The patient presented to MGM Hospital, Kamothe, 4 months later with worsening lower backache, bilateral lower limb weakness with knee extension (3/5) and ankle dorsiflexion (3/5). On repeating radiological investigations, radiographs showed progressive destruction of L3 and L4 disc space and a magnetic resonance imaging with contrast showe increased abscess collection within the spinal canal compressing the thecal sac at L3-4 level. In view of the significant stenosis, expanding abcess and progressive deficit, surgery was planned in the form of decompression, fixation and fusion with curettage and biopsy. A short segment fixation from L2 to L4 was planned along with Laminectomy at L3 level and Transpedicular decompression and curettage of Sequestrum at L3-4-disc space followed by placement of large titanium cage and bone graft. Intra-op samples were sent for histopathological examination and culture, were positive for Mycobacterium tuberculosis but were also positive for Staphylococcus aureus. Results: Post operatively, antibiotics were started according to the reports and patient was discharged with suture removal advised at 2 weeks post-op. At 3 month follow up, patient did complain of some residual back pain but improved VAS and ODI scores along with recovering neurological deficit and improving blood and radiological parameters with no evidence of implant loosening. Conclusion: Multiple risk factors may be associated with the development of polymicrobial abscesses in the lumbar spine. Careful anticipation, identification, and isolation of the causative micro-organisms can ensure effective antibacterial treatment. Early diagnosis, expeditious surgical decompression, and antibiotic treatment are associated with promising outcomes. Shahidul Islam 1,2 , Saleh-Al-Nayem Chy. 2 , Tonima Sabikun 2 1 Ad-din Women’s Medical College, Orthopedics and Spine Surgery, Dhaka, Bangladesh , 2 Barak PRP Medical Centre, Orthopedics and Spine Surgery, Dhaka, Bangladesh Introduction: Chronic low back pain has multiple etiologies, including degenerative, neoplastic, inflammatory and infectious causes. Among them, the major cause of infection is tubercular spondylodiscitis. The concomitant occurrence of TB spondylodiscitis and pyogenic infection is extremely rare and possesses unique diagnostic and therapeutic challenges. Although, tuberculosis of spine or Pott’s disease is common in Indian subcontinent, pyogenic infection of spine is rare. In this case report, we aim to describe the diagnosis and management of a highly uncommon case of simultaneously occurring TB and pyogenic infection of spine in a 70-year-old male. Materials and Methods: The patient presented with chronic low back pain and inability to walk for 2.5 months. MRI revealed a paraspinal mass at the L2-L5 level, suggestive of TB spondylitis, and disc herniation at L3/4 and L4/5. The patient underwent laminectomy of L3, L4, and L5, along with discectomy of L3/4 and L4/5, followed by stabilization using eight titanium pedicle screws. Per-operative pus was collected and culture was done, identifying E. coli and S. aureus . Biopsies from the L4-L5 disc done in two diagnostic centers showed conflicting results: one indicated inflammation, and the other confirmed TB spondylodiscitis. Result: Post-operatively, the patient showed significant improvement in pain and mobility. No intraoperative or postoperative complications occurred. The patient was discharged from hospital with appropriate medication along with anti TB drugs and advised for follow up. Conclusion: The rare co-occurrence of TB and pyogenic spondylodiscitis exhibits diagnostic and therapeutic challenge. Timely diagnosis and proper management is crucial for a significant clinical outcome. Pankaj Kandwal 1 , Parshwanath Bondarde 2 , Kaustubh Ahuja 2 , Siddharth Sethy 2 1 All India Institute of Medical Sciences, Rishikesh, Orthopaedics, Rishikesh, India , 2 All India Institute of Medical Sciences, Rishikesh, Rishikesh, India Background: The drug resistance of tuberculosis has worsened the existing burden. This prospective observational study was conducted to ascertain drug resistance pattern and analyse outcomes of chemotherapy in drug resistant spine tuberculosis. Methods: An observed cross-sectional study was conducted. 324 cases were clinic-radiologically diagnosed as tuberculosis of spine. Tissue samples obtained percutaneously (45.67%, 148/324) and during surgery (54.32%, 176/324) were subjected to molecular studies (CBNAAT, LPA) and culture (BACTEC MGIT 960 culture). All the patients were serially followed up with radiological investigation, blood parameters and PROMs. Results: Females (56.2%) outnumbered males. Majority of cases were young patients (Avg age = 29.2 ± 16.6), early presenters and neurologically intact at presentation. The drug sensitivity testing revealed 16 (4.93%) cases of drug resistance, 14 cases were multi drug resistant (87.5 %) and 2 mono resistant cases to isoniazid (12.5%). 11 of 16 cases were managed by surgical intervention. No significant statistical difference between post operative PROMs of MDR and NON MDR. Conclusion: Incidence of drug resistance in spinal tuberculosis is 4.93 percent. Multi drug resistance to both isoniazid and rifampicin is common. Drug resistant tuberculosis fair similarly as non-resistant tuberculosis. Empirical chemotherapy resulted in good healing similar to non-resistant tuberculosis. Istvan Klemencsics 1 , Balazs Szollosi 1 1 Buda Health Centre, Spine Surgery, Budapest, Hungary Introduction: Platelet-rich plasma (PRP) is a new biological therapy being investigated for use in LBP. Lumbar intradiscal PRP injections can be a cheap, feasible and safe treatment to counter IVD degeneration associated LBP. Disc space infection is an especially rare adverse event following the injection of PRP. Material and Methods: 43-year-old man patient without any internal diseases underwent PRP injection at the level of L.IV/V and L.V/S.I due to disc degeneration in a private outpatient pain clinic. He had worsening LBP 2 weeks later. His back pain worsened 2 weeks after the procedure. Multiple control MRI examinations showed the development of spinal infection in the L.IV-S.I level. Despite prolonged oral and IV antibiotic therapies, spinal infection progressed locally, causing bone destruction. One of the bacterial cultures verified Staphylococcus epidermidis infection. The patient applied for an examination at our clinic 5 months later after the PRP injection. CT and MRI showed significant progression with endplate lesions, and inflammatory signs in the foramens and paravertebral tissues. Results: We performed surgical debridement 2-level TLIF fusions and L.IV-V-S.I posterior stabilization. Intraoperative cultures showed Coagulase-negative staphylococci (CoNS) species. Patient received prolonged antibiotic therapy after surgical treatment (2 weeks intravenous, and 3 months oral antibiotic therapy). The patient’s mobility and the load capacity of his lumbar spine improved considerably after surgery. No complications occurred in the early postoperative period. 3 months after the operation, the patient does not need analgesics and can walk 5 km without an aid. Conclusion: Based on literature data, intradiscal infection after lumbar intradiscal PRP injection is extremely rare. According to the results of bacterial cultures, contamination and inadequate sterility of the intervention may have caused the extensive spinal infection. Due to the fact that this case is sporadic, general conclusions cannot be drawn from it. However, the case provides useful information about rare but serious complications that can occur with PRP therapy. Romdhane Denguezli 1 , Mohamed Amine Triki 1 , Sofien Benzarti 1 , Hassini Lassaad 1 , Mahmoud Ben Maitigue 1 , Karim Bouattour 1 1 Sahloul Hospital, Orthopedic Department, Sousse, Tunisia Introduction: Infectious spondylodiscitis of the cervical spine is a serious and relatively rare condition, especially in children. Diagnosis is often challenging due to a nonspecific clinical presentation. It can progress to nerve irritation, either through nerve compression and/or cervical spine deformity. Materials and Methods: We report the case of a 4-year-old boy who presented with torticollis without a history of trauma. On examination, the child was afebrile, and the only notable finding was cervical stiffness. He was admitted to the pediatric department, where cervical ultrasound revealed multiple cervical lymphadenopathies. His C-reactive protein (CRP) was 49, and leukocyte count was 8,000; however, the bacteriological investigation was negative. MRI findings suggested Langerhans cell histiocytosis of the C5 vertebral body with inversion of cervical lordosis. A percutaneous biopsy showed C5 spondylodiscitis. The child was subsequently transferred to the orthopedic surgery department. A follow-up MRI revealed the presence of a prevertebral abscess at C5 with intramedullary expansion. Despite the initiation of cervical traction and antibiotic therapy, the clinical course was marked by the onset of pyramidal signs and worsening cervical kyphosis. Results: The patient subsequently underwent C4-C5 and C5-C6 discectomy with debridement, placement of an expandable cage, and cervical plate osteosynthesis, along with intravenous antibiotic therapy using glycopeptides and third-generation cephalosporins for 3 weeks. The cervical spine was stabilized with a full cervical collar. Histopathological examination revealed the presence of caseous necrosis, confirming the tuberculous origin of the lesion. The child was then placed on antituberculous therapy for 8 months. Postoperatively, the course was uncomplicated. The child regained the ability to walk, and neurological signs resolved. At an 8-month follow-up, the examination showed no abnormalities. Conclusions: This nonspecific clinical presentation initially led us to consider an infectious origin. Given the context, a pyogenic cause was unlikely, but other bacteria, such as Kingella kingae, were possible. Brucellosis and hematological malignancies were also considered. The worsening kyphosis prompted us to contemplate osteosynthesis despite the likely septic context. The emergence of neurological signs compelled us to take the risk of performing the osteosynthesis, a relative risk since the underlying condition turned out to be tuberculosis. In this pediatric indication, the use of an expandable cage is an advantageous alternative that does not hinder growth and is particularly relevant in this case. Maria Ilaria Borruto 1 , Laura Scamuzzo 1 , Calogero Velluto 1 , Domenico Alessandro Santagada 1 , Giovangiuseppe Mazzella 1 , Luca Proietti 1 1 Policlinico Universitario A Gemelli IRCSS, Rome, Italy Introduction: Pediatric spondylodiscitis’ management requires a multidisciplinary approach involving spine surgeons, infectious disease specialists, interventional radiologists. The prevalence of this disease has increased in frequency, virulence, and soft tissue involvement in recent years. There has also been a resurgence of certain types of infections, such as tuberculosis, fungi, and viral pathogens. Diagnosis is often achieved through a detailed history, physical examination, laboratory analysis, and imaging studies. Sometimes, a more invasive diagnostic approach is needed, including core or open biopsy. The treatment of spondylodiscitis in children is sometimes complex, and while many infections can be treated non-surgically with antibiotic therapy, some more extensive infections require surgical intervention. Timely diagnosis is important as it allows early start of appropriate antimicrobial therapy and reduces the likelihood and complexity of surgery. Often no etiological agent is identified, and early empirical therapy alone has been sufficient to control and resolve the condition. Material and Methods: Our study is a case series of two patients under 2 years of age (one affecting C2 and the other the thoraco-lumbar spine) and a literature review that analyzes the diagnosis and management of pediatric patients with spondylodiscitis. Results: There is a triphasic distribution of primary vertebral infections, with 79% of cases occurring between six months and four years of age, 20% in the juvenile and adolescent age group, and 1% in children under six months. The most affected site is the lumbar spine. Symptoms of pediatric spondylodiscitis depend on the child's age: in infants, it manifests as irritability, while in toddlers, it presents as limping, refusal to sit or walk, and abdominal pain; 75% of them will not have a fever. Older children may present with back pain and tenderness to palpation. Diagnosis is often delayed (an average of 29 days). It must be differentiated from eosinophilic granulomas, leukemia, lymphoma, fibrous dysplasia, or Ewing's sarcoma. In 50.7% of cases, antibiotic therapy is empirical, in the absence of positive blood cultures, and in 73% of cases, treatment is conservative. Conclusion: Pediatric spinal infections, though rare, require a prompt and accurate diagnosis to minimize the risk of complications and the need for surgery. A multidisciplinary approach is essential for effective management. Early identification of symptoms, even in the absence of fever or positive cultures, is crucial for timely treatment, reducing the likelihood of delayed diagnosis and long-term morbidity. As demonstrated in our case series and literature review, understanding the age-specific presentation and differential diagnoses is key to improving outcomes in pediatric patients with spondylodiscitis. Aminu Nuraddeen 1 , Kabir Abubakar 2 , Kawu Ahidjo 3 1 National Orthopaedic Hospital, Dala, Spine UNit, Kano, Nigeria , 2 Ansar Orthospinal Hospital, Kano, Nigeria , 3 University of Abuja, Orthopaedics, Abuja, Nigeria Abstract: Spinal infections typically present with pain, fever, paralysis, incontinence and other manifestations. In developing countries with high endemicity for Pott’s disease, poor resources and limited access to healthcare, presentation with deformities is common. While the literature is replete with neuroschistosomiasis with spinal schistosomiasis a more common form of it, vertebral schistosomiasis with kyphotic deformity is rarely reported. We present a case of vertebral schistosomiasis with kyphotic deformity that mimicked Pott’s disease and was treated as such until a histologic diagnosis supported by a history suggestive of schistosomal infection obtained in retrospect proved otherwise. Introduction: Schistosomiasis is a disease of poverty that leads to chronic ill-health. It affects almost 240 million people worldwide and more than 700 million people live in endemic areas. Human schistosomiasis is caused by five species of the parasitic genus schistosoma. S. mansoni, S. japonicum, S. mekongi, and S. intercalatum cause intestinal disease while S. haematobium causes urogenital disease. Africa is by far the most affected by schistosomiasis with 85% of estimated global cases occurring on the continent. Spinal schistosomiasis, the best known form of neuroschistosomiasis is a rare and a severe underdiagnosed form of schistosomiasis that occur at any time during the parasitic infection. It is caused by ectopic deposition of schistoma eggs in the spinal cord and occasionally adult worms have been found in leptomeningeal veins. Mycobacterium tuberculosis is a common pathogen found to be a more prevalent cause of infectious myelopathy in Africa (30%). Spinal tuberculosis is estimated to occur in 1-5% of all TB cases. It is the most common cause of kyphotic deformity in many parts of the world. The clinical manifestations are caused by destruction of vertebrae or by a paraspinal abscess. Hence, the diagnosis of Pott’s disease is by far the more likely in the setting of kyphotic deformity of infective origin. Case Summary: The patient is a 25 year student who was referred from another tertiary centre with history of mid back pain of 12 years and gradual onset of lower limb weakness and paraesthesia of a month duration. The back pain had worsened 6 months prior to presentation and he had developed a kyphotic deformity with increasing difficulty in carrying out activities of daily living. His sphincters were not impaired. A diagnosis of Pott’s disease was made and he was commenced on antituberculous treatment 3 months prior to presentation albeit with worsening of pain and neurology. Significant findings on examination were mild pallor, gibbus deformity in the lower thoracic spine with tenderness and paravertebral muscle spasm. Power on the right L2-S1 was 4/5 on MRC scale while on the left L2-L4 was 2/5 and L5-S1 was 4/5. There was also hypotonia and hyporeflexia. His pain score was 8 on the Visual analog scale (VAS). Plain radiograph revealed T12 collapse with obliteration of T12/L1 intervertebral space and a kyphotic angle of 28 0 . MRI revealed. He had an ESR of 98mmhr -1 and mantoux was 7mm. He was placed on analgesics initially and he later had posterior decompression and kyphotic deformity correction with pedicle screws and rods and the resected vertebral wedge was sent for histology and microscopy culture and sensitivity. Patient improved post operatively with neurology returning to normal and back pain reducing to 4 on VAS. He was also able to walk upright, lie flat and tolerate sitting and standing for long periods. Histology yielded aggregates of epithelioid histiocytes with occasional giant cells ingesting schistosoma ova. Other areas in the stroma also demonstrated numerous calcified schistosoma ova. In retrospect, a history of haematuria for 15 years and bathing in streams and ponds was obtained from the patient. He was subsequently treated with praziquantel and back pain subsided completely. Discussion: The characteristic clinical features of spinal tuberculosis include local pain, local tenderness, stiffness and spasm of the muscles, a cold abscess and a prominent spinal deformity. Spinal deformity is a hallmark feature of spinal tuberculosis. Type of spinal deformity depends on the tuberculous vertebral lesion, kyphosis the most common spinal deformity occurs with lesions involving the thoracic vertebrae. The current clinically recognized indications for surgery are severe back and/or radicular pain, resistance to conservative treatment, developing neurological deficit, significant kyphosis (> 30%) or progressive deformity. Worldwide 90% of cases of neuroschistosomiasis are estimated to occur in sub-Saharan Africa although an increasing number of cases outside of endemic areas are being noted due to global travel. Diagnosis can be difficult and significantly delayed. The clinical, radiological and laboratory manifestations of the index patient mirror that of Pott’s disease which serendipitously led to the histological diagnosis of schistosomiasis. Parasitic infections present a unique challenge in treatment, particularly due to a delay in diagnosis thereby preventing patients from receiving early antihelminthic treatment. A thorough patient history, pertinent serological tests and most notably advanced imaging are necessary for correct diagnosis. Although these diagnostic aids may help guide the clinician towards identifying the cause of the patient’s presenting symptoms, biopsy and histology will be necessary in most unsolved cases. It is evident from our case that a history suggestive of schistosomiasis was not sought as all features mimicked Pott’s disease and this presentation is not a common presentation as our literature search only found one case that presented in this manner. The relief from pain was not complete despite surgery, antikoch’s medications and analgesics until antihelminthic agents were administered Conclusion: Despite the endemicity of schistosomiasis in sub-Saharan Africa, detailed history suggestive of schistosomiasis does not feature prominently in the clinical evaluation of patients with infectious diseases of the spine leading to significant delay in diagnosis and treatment. This becomes even more so when the presentation is that of a vertebral disease rather than a myelopathy. Such history should be routine and clinicians should have a high index of suspicion especially when response to antiKoch’s medications is not satisfactory. Keywords: Vertebral schistosomiasis, spinal schistosomiasis, Pott’s disease, kyphotic deformity, kyphotic deformity correction Nishank Mehta 1 , Bhavuk Garg 1 1 All India Institute of Medical Sciences, New Delhi, India Introduction: Spinal tuberculosis (STB) has a high prevalence in developing countries. With increasing life expectancy and better access to healthcare, increasing cases of STB in geriatric population are coming forth. The present study aims to highlight the presenting features and prognosis (treatment outcomes and complication rates) of STB in the geriatric population, and compare it with a younger population cohort. Materials and Methods: Hospital records of STB patients treated over 7 years (2015-2021) were retrospectively reviewed - patients were segregated into a study group (patients aged > 60 years) and comparator group (patients aged ≤ 60 years). Patients were treated in accordance with the ‘middle-path regime’, with surgery being reserved for selected indications. The two groups were compared with respect to pre-defined clinical, radiological and functional outcome measures. Results: A total of 167 geriatric patients and 1252 younger adult patients were included. Geriatric patients had a more delayed presentation (5.4 ± 2.6 months v/s 3.8 ± 2.1 months), lower incidence of constitutional symptoms at presentation (27% v/s 36%) and a higher affliction with concomitant comorbidities (75% v/s 17%). A significantly higher proportion of patients aged more than 60 years presented with a neurological deficit (55/167, 33% v/s 237/1252, 19%) and eventually required surgery (46/167, 27% v/s 127/1252, 10%) - one of more complications during the course of treatment were seen in 61/167 (37%) of patients in the study group, with the most common complication being intolerance to one or more first-line antitubercular drugs. There was a higher proportion of geriatric patients with multi-level involvement (25% v/s 17%) and a ‘central’ type of tubercular lesion (19% v/s 12%). The diagnostic yield of image-guided biopsy (histological or microbiological diagnosis confirming tuberculosis) was poorer in geriatric patients compared to the younger population. Conclusion: STB in geriatric patients presents unique challenges – possibly due to their poor bone quality, presence of comorbidities and a relatively compromised immune status. Significant differences in the presentation, treatment outcomes and complication rates were noted in these patients when compared to a younger population cohort. A more cautious and pro-active stance is warranted in geriatric patients with spinal tuberculosis to avoid complications and poor outcomes. Carlos Pacichana 1 , Carlos Alberto Carmona Lorduy 2 , Eliana Melissa Marcillo Vinueza 1 , Saidy Inés Buendia Pérez 1 , Gina Velásquez Solano 3 , Nelly Patricia Martinez Muñoz 4 1 Universidad de Cartagena, Cartagena, Colombia , 2 Hospital Universitario del Caribe, Cartagena, Colombia , 3 Universidad de los Andes, Bogotá, Colombia , 4 Hospital San Jose , Popayan, Colombia Introduction: Surgical site infections occur in 2% to 5% of all surgical procedures, leading to significant economic losses and increased postoperative morbidity, prolonged hospitalization, and healthcare costs. Properly using a systematic approach and negative pressure instillation therapy (NPIT) can be an effective alternative for treating postoperative infections in the lumbar spine. This approach aims to reduce complexity, avoid complications, and promote wound closure by applying subatmospheric pressure and periodic washing of the affected wound. Material and Methods: This study included 10 patients admitted to two hospitals in Cartagena, Colombia, who required surgical management for spinal pathologies and negative pressure therapy with instillation (NPIT). These patients had a history of spinal surgery and presented symptoms such as local heat, erythema, cutaneous fistulas, and purulent secretion. Initial treatments with surgical lavages and debridements every 48 hours showed poor response. Results: In one case, removal of spinal instrumentation was necessary. In the remaining 9 cases, 4 patients had lumbar osteosynthesis material, and 1 patient had a bone defect after a previous surgery. After initiating negative pressure therapy with instillation, all patients showed satisfactory results, with clean granulation tissue suitable for closure. This approach reduced surgical times, the need for systemic anesthetics, and orotracheal intubations, and allowed for a staged closure. Conclusion: Infections following spinal surgery are a significant problem, leading to morbidity and mortality. The use of negative pressure therapy with instillation can reduce healthcare costs, promote faster healing, and shorten hospital stays. This approach also minimizes the need for systemic anesthetics and orotracheal intubations and optimizes the debridement of infected wounds.

David Shin 1 , Olumide Danisa 2 , Wayne Cheng 3 1 Loma Linda University School of Medicine, Loma Linda, United States , 2 Duke University Health System, Durham, United States , 3 Jerry L Pettis Memorial Veterans Hospital, Orthopaedic Surgery, Loma Linda, United States Introduction: Modern neurosurgical technique requires clearance of the iliac crests during anterior and anterolateral approaches. Understanding the level of the iliac crests is crucial in planning for transpsoas fusion approaches. This study aimed to determine if the iliac crests are truly at the level of L4-L5, accounting for patient demographic and anthropometric characteristics. Materials and Methods: We measured the umbilicus and iliac crests relative to the lumbar spine using computed tomography (CT) of patients without spinal pathology, accounting for the influences of patient height, weight, body mass index (BMI), sex, race, and ethnicity. Results: A total of 834 patients, 391 male and 443 female, were reviewed. The location of the umbilicus relative to the lumbar spine demonstrated a unimodal distribution pattern clustered at L4 while the iliac crests were most frequently located from L4 to L5. 26.5% of the time, iliac crests were located above the L4-L5 disc space. 29.8% of the time, iliac crests were located at the L4-L5 disc space. No correlations were observed between the umbilicus and iliac crests with patient height, weight, or BMI. There was no difference in the location of the umbilicus with respect to patient sex, race, and ethnicity. The locations of the iliac crests were cephalad in females compared to males, and in Hispanics compared to African American, Caucasian, and Asian subjects. Conclusions: The iliac crests were located above the level of the L4-L5 disc space approximately 26% of the time. The umbilicus is most frequently at the level of the L4 vertebral body. Patient height, weight, and BMI do not influence the location of the umbilicus nor the iliac crests relative to the lumbar spine. Patient sex and ethnicity influence the location of the iliac crests but not the umbilicus relative to the lumbar spine. Diana Chávez 1 , Alberto Perez 1 1 Hospitales Angeles, Neurosurgery, Mexico, Mexico Introduction: The morphometric evaluation of the intervertebral disc involves the quantitative analysis of its shape, size, and structure. This assessment is crucial for diagnosing and monitoring conditions that affect the spine, such as disc degeneration, herniation, or trauma. By utilizing advanced imaging techniques like magnetic resonance imaging (MRI) or computed tomography (CT) scans, healthcare professionals can obtain precise measurements of height, volume, and other parameters of the disc to assess its health and integrity. Morphometric evaluation plays a key role in treatment planning, patient management, and evaluating treatment outcomes for spine-related disorders. Using 7D neuronavigation for the morphometric evaluation of the intervertebral disc involves advanced technology to accurately measure and analyze the dimensions and characteristics of the disc. Neuronavigation systems provide real-time image-guided assistance during spinal surgeries, enabling surgeons to navigate with greater precision and efficiency. Material and Methods: A 45-year-old male patient has been diagnosed with degenerative disc disease at the L5S1 level. An anterior approach interbody fusion at L5S1 was performed using 7D neuronavigation. Pre-procedure measurements were taken to select the specific interbody cage that met the surgical objectives. Comparative measurements of the treated level were conducted to assess outcomes. Results: The pre-procedure measurements were as follows: anterior disc height of 11.3 mm, posterior disc height of 6.6 mm, intersomatic angulation of 9.2 degrees, anteroposterior length of 29.4 mm, and platform width of 53.1 mm. The post-procedure measurements were: anterior disc height of 14.3 mm, posterior disc height of 8.1 mm, and intersomatic angulation of 11.9 degrees. Conclusion: The intraoperative use of morphometric measurements with 7D neuronavigation provides the opportunity to place a specific implant and offers greater precision in pre-planned corrections for patients undergoing lumbar surgery with interbody fusion. This approach also helps reduce subsidence related to the size of the implant. Eu Gene Teo 1 , Sang Xian, Leonard Leong 2 , Chin Hwee Goh 3 , Sii Hieng Wong, Albert 1 1 Sarawak General Hospital, Neurosurgery, Kuching, Malaysia , 2 Hospital Sungai Buloh, Neurosurgery, Sungai Buloh, Malaysia , 3 Hospital Melaka, Neurosurgery, Melaka, Malaysia Introduction: Pedicle screw insertion for spinal fixation is a commonly used technique to immobilise an unstable spine. The emergence of Image Guided Surgery (IGS) has revolutionised spinal surgery, allowing surgeons to perform pedicle screw insertion with greater accuracy and safety. One of the key components of an IGS system is the reference array, which has to remain at a fixed point throughout the surgery. The aim of this study was to investigate the relationship between pedicle screw insertion accuracy and the distance from the IGS reference array. Material and Methods: A total of 93 pedicle screws (18 cervical, 49 thoracic, and 26 lumbar) were inserted in 21 patients at Hospital Umum Sarawak between October 2017 and July 2022. The accuracy of screw placement was evaluated using post-operative CT scans. The screws were rated on the Gertzbein-Robbins (GR) classification scale, which assigned Grades 0-3 (Grade 0: Screw within pedicle, Grade 1: ≤ 2 mm breach, Grade 2: > 2 - 4 mm breach, Grade 3: > 4 mm breach). The pedicle screw placement was further divided into “Satisfactory Placement” (Grade 0-1) and “Unsatisfactory Placement” (Grade 2-3). Results: The accuracy of screw placement was satisfactory (≤ 2 mm) in 80.6% of all segments. A distance from the reference array of up to four segments did not significantly affect screw placement accuracy when using IGS guidance. One patient experienced a CSF leak likely due to a dural tear during the initial pedicle screw fixation. The results suggested that the distance from the reference array did not significantly affect screw accuracy within the studied range (up to four segments). Conclusion: IGS guided pedicle screw insertion is a valuable technique for improving accuracy and safety in spinal fusion surgery. Qin Huang 1 , Priyambada Kumar 1 , John Ruiz 1 , Naresh Kumar 1 1 National University Health System, Orthopaedic Surgery, Singapore, Singapore Study design: Case report. Introduction: Lumbar spondylolysis, a common stress fracture in middle and high school athletes, is typically managed conservatively in its early stages. Although surgical repair using Buck’s technique is well-documented, there is limited literature on the minimally invasive Buck’s repair aided by intra-operative O-arm navigation. In this study, we present the case of a 14-year-old student athlete with recurrent lumbar spondylolysis, successfully treated using O-arm-assisted pars defect repair with minimally invasive Buck’s technique. Methods: We present the case of a 14-year-old student athlete suffering from chronic, debilitating lower back pain that did not improve with multiple conservative treatments and epidural blocks. Radiological imaging identified left-sided L5 lumbar spondylolysis. PET CT scan showed no active uptake in this region, confirming the chronic nature of the lesion. After thorough informed counselling, the patient underwent surgery for repair of the left pars defect. A navigation clamp was placed at the L4 spinous process. Through a 3cm left paraspinal incision, the defect was located under O-arm guidance, and the defect edges were decorticated and filled with autologous bone graft harvested from the ipsilateral iliac crest. A single fully threaded 4.0-mm-diameter titanium cannulated screw was inserted across the defect, achieving direct compression. While autologous bone graft was used in this case, the use of BMP for filling the fracture defect is a viable alternative . Results: The operative time was 190 minutes and estimated blood loss was 50ml. There were no intra-operative or peri-operative complications. The patient was made to mobilise on post operative day 1 under physiotherapist care and was allowed to return to non-strenuous activities of daily life in the next 3 weeks. Length of hospital stay was 2 days. VAS score for back pain was 4/10 at 10 days post-operatively and 0/10 at 6 weeks and 0/10 at 6 months post-operatively. ODI score was 22 & 8 at 3 and 6 months post-operatively. CT scan done at 6 months post-operatively revealed a united fracture defect. Conclusion: Lumbar spondylolysis treatment with a minimally invasive direct pars repair is a safe and technically feasible option that minimizes muscle and soft-tissue dissection, which may particularly benefit adolescent patients with a desire to return to a high level of physical activity. Shrey Binyala 1 , Vishal Peshattiwar 1 1 Kokilaben Dhirubhai Ambani Hospital, Mumbai, Maharashtra, Spine Surgery, Mumbai, India Introduction: The anatomy of the S1 pedicle is peculiar with a large diameter, short length, highly cancellous, and lacks a cortical ring. The L5-S1 junction is a transitional motion segment and has an oblique disc space which increases the shearing forces acting at this junction to a great extent. All these factors lead to the loosening of the S1 pedicle screw by about 41%. The known anteromedial and anterior trajectories allow the placement of 30-40 mm screws. Material and Methods: This Prospective study was conducted between 2019 and 2022 with 117 patients who underwent L5-S1 MIS-TLIF (Minimally Invasive Spine Surgery – Transforaminal Lumbar Interbody Fusion), hence we analyzed 234 screws inserted under CT navigation. In our study, we took an entry point 15 mm caudal and 10 mm lateral to the base of the superior articulating facet for percutaneous placement of the S1 pedicle screws, with the cranio-caudal angulation of 60° and the latero-medial angulation of 20°. Results: In our study of 52.14% females, we analyzed 234 S1 pedicle screws. We observed that in males we could use a mean length of 45.90 mm and 44.88 mm in females. The mean cranio-caudal angulation of all our screws averaged between 50-65°. The structural finite element analysis was done with the help of OptiStruct: Optimization-enabled Structural Analysis. Our construct was found to be biomechanically superior as compared to the conventional method of inserting the S1 pedicle screw. This new trajectory allowed us to use a longer and more acute angled lever arm to hold the L5-S1 segment in place, ultimately increasing the construct's pull-out strength. Bridwell grade 1 fusion was seen in 115 out of 117 patients by the end of 2 years. Conclusion: A new trajectory of the S1 screw with an entry point caudal to the standard point and an increase in craniocaudal angulation allowed us to put longer S1 pedicle screws of 45mm or more giving a better load-bearing strength and overall higher biomechanical stability as compared to the conventional technique for L5-S1 fusio

Bruno Verna 1 , Artine Arzani 1 , Thomas Caffard 1,2 , Vidushi Tripathi 1 , Erika Chiapparelli 1 , Jiaqi Zhu 3 , John Carrino 4 , Jennifer Shue 1 , Andrew Sama 1 , Frank Cammisa 1 , Federico Girardi 1 , Alexander Hughes 1 1 Hospital for Special Surgery, Spine Care Institute, New York, United States , 2 University of Ulm, Department of Orthopedic Surgery, Ulm, Germany , 3 Hospital for Special Surgery, Department of Epidemiology and Biostatistics, Weill Cornell Medicine, New York, United States , 4 Hospital for Special Surgery, Department of Radiology and Imaging, New York, United States Introduction: Evidence that individuals with osteoporosis have demonstrated an increased susceptibility and frequency of sarcopenia has led to the creation of the term “osteosarcopenia”. Given DXA's limitations in spine BMD assessment, novel techniques such as MRI-based vertebral bone quality (VBQ) are increasingly being utilized to quantify site-specific bone quality in the spine. The relationship between cervical paraspinal muscle morphology and cervical bone quality has not been investigated. This study aims to explore the relationship between cervical VBQ scores and paraspinal muscles parameters. Material and Methods: Patients with preoperative cervical MRI imaging who underwent anterior cervical discectomy and fusion between 2015 and 2018 were reviewed. Muscles from C3 to C7 were categorized into 4 functional groups: sternocleidomastoid group, anterior group, posteromedial and posterolateral group. For all groups, the cross-sectional area (CSA), functional CSA (fCSA), and percent fat infiltration (FI) were measured. VBQ scores of the cervical vertebral bodies were performed using prior established methodologies. Multivariable linear regression analyses adjusted for age, sex, and body mass index were performed. The Benjamini-Hochberg procedure was applied to adjust p-values. Results: A total of 75 patients (median age 55.4 years; 26 females) were included. A greater VBQ score indicates high fat content of the bone and was significantly associated with the presence of osteopenia/osteoporosis, meaning that high VBQ scores indicate lower bone quality and low VBQ scores indicate better bone quality. After adjusting for age, gender and body mass index and adjusting p-values with the Benjamini-Hochberg procedure, regression analysis revealed significant negative correlations between the fCSA of anterior muscle group and VBQ scores from C2 to T1 and a significant positive correlation between the FI of the anterior muscle group with VBQ scores from C2 to T1. Conclusion: This study presents novel insights into the relationship between cervical vertebral bone mineral quality and paraspinal muscle parameters, particularly at the C3 level, which shows the highest number of significant correlations. The findings suggest that measurements of paraspinal muscles at C3 could serve as a proxy for assessing bone quality across the subaxial cervical spine, offering a new perspective in preoperative evaluations for cervical spine surgery. This study is the first to report significant correlations between VBQ measured bone mineral quality and paraspinal muscle throughout the subaxial cervical spine. Yan Silva 1,2 , Newton Pimenta 2 , Bernanrd LaRue 2 , Jerome Couture 2 , Jocelyn Blanchard 2 , Julien Goulet 2 1 Hospital Ortopédico do Estado, Salvador, Brazil, 2 Université de Sherbrooke, Sherbrooke, Canada Introduction: The most familiar defects in the neural arch of the spine are spina bifida occulta and spondylolysis, retrossomatic CLEFTs are a less common one. They may occur as persistant synchondrosis, pedicular (retrosomatic) cleft, pars (Spondylolysis), retroisthmic, paraspinous, and supraspinous (Spina bifida). The aim of the study is to describe a rare case of spinal malformation encompassing multilevel bilateral lumbar retrosomatic cleft and pedicular dysplasia in a patient that presented with a vertebral compression fracture. Materials and Methods: A 60 y.o. female known for controlled systemic scleroderma and hypothyroidism presented with a typical low-energy osteoporotic compression fracture at L1 after lifting a heavy object. She is otherwise healthy and working in a physically demanding environment. She had back pain and neurological examination was normal. No clinical stigmas of neurofibromatosis (NF) was found. The X-ray showed a typical lumbar compression fracture at L1 and dense thin pedicules at the lumbar levels. CT scan showed an acute on chronic burst fracture of the upper endplate of L1. It showed an overall enlargement of the thoracolumbar spinal canal secondary to multiple bilateral retrosomatic clefts from T12 to L3 within which small asymmetrical round calcifications were found. The patient was treated conservatively without bracing and had a good recovery, returning to her full time job 8 months after the event. Results: As Johansen et al found, clefts may occur in the pedicle, pars or lamina. From that we know, this is the first documented case of multilevel retrosomatic cleft presenting which such diastasis between pedicular margins. Most cases describes a single level vertical sclerotic cleft at the base of the pedicule. Soleimanpour et al described a multilevel case in a rhumatoid patient without enlarged spinal canal. Although the pedicular dysplasia is similar to the neurofibromatosis radiological stigmas, no clinical history or objective signs suggest a concomitant NF diagnosis in this case. It’s important to recognize the condition and the treatment in any patient with spinal congenital anomalies must be tailored according to a thorough evaluation of clinical, radiological and surgical factors. Conclusion: In summary, this case highlights the rarity of atypical pedicular malformations with multilevel lumbar retrosomatic cleft and associated pedicular dysplasia. The unique nature of this case emphasizes the potential challenges and considerations in spinal surgery. Josephine Coury 1 , Fthimnir Hassan 1 , Gabriella Greisberg 2 , Justin Reyes 1 , Alexandra Dionne 1 , Yong Shen 3 , Joseph Lombardi 1 , Zeeshan Sardar 1 , Ronald A. Lehman 1 , Lawrence Lenke 1 1 Columbia University Irving Medical Center, New York, United States , 2 Touro College of Osteopathic Medicine, New York, United States , 3 The Johns Hopkins Hospital, Baltimore, United States Introduction: Lower instrumented vertebra (LIV) selection in Adult Idiopathic Scoliosis (AdIS) surgery presents challenges in achieving optimal alignment while minimizing fused motion segments. Traditionally in adolescent idiopathic scoliosis, the last touched vertebra (LTV) on upright films is selected, however recent literature suggests the supine LTV can also serve as a safe LIV. This study aimed to evaluate the LTV on both upright and supine films as well as the impact of substantial contact with LIV on radiographic outcomes. Methods: This was a retrospective study of AdIS patients from a single center with fusion constructs ending proximal to the sacrum and minimum 2-year follow-up. Radiographic measurements included C7-trunk shift, distance from center of LIV to CSVL (central sacral vertical line), disc angle below LIV, and C7-SVA (sagittal vertical axis) and were measured at preop, immediately postop, and at 6 months, 1, and 2 years. All measurements were performed on standing radiographs (except for preop supine LTV). Patients were categorized into 6 groups based on the upright LTV, supine LTV, and LIV: 1) had identical LTV for both upright and supine which was used as LIV, 2) upright LTV was LIV, 3) supine LTV was LIV. Differentiators A and B were added to indicate if the LTV had substantial contact, either touching/medial (A) or lateral (B) to the pedicle. Results: 55 AdIS patients were identified with average 2.6yr follow up, predominantly coronal deformity (average major curve 57°, range 34°-136°), and an LIV between T12-L5. Postop, average trunk shift decreased from 17.81 mm preop to 6.79 mm after 2 yrs (p < 0.0001). C7-SVA also improved from 22.95 mm to 11.33 mm in 2 years (p < 0.01). Disc angle distal to LIV decreased from 2.8° postop to 0.7° in 2 years (p < 0.001). No instances of distal adding on, junctional kyphosis, or revision surgery occurred. The most notable differences were observed between groups A (n = 3 6) and B (n = 17). At 6 months and 2 years, the distance from CSVL to LIV was lower in groups 1A (n = 6), 2A (n = 18), 3A (n = 13) compared to1B (n = 3), 2B (n = 6), 3B (n = 9) (3.7 vs 7.5, p = 0.004; 3.2 vs 6.9, p = 0.01). This distinction was seen immediately postop and at 2 years in trunk shift (10.8 vs 18.4, p = 0.05; 5.2 vs 9.3, p = 0.03) and at 2 years in C7-SVA (7.6 vs 16.5, p = 0.003). Group 3B had a larger distance from CSVL to LIV at 6 months compared to 1A and 2A (8 vs 2.33 and 2.76, p < 0.03). Trunk shift was notably lower in 2A vs 3B immediately and at 6 months (7.4 vs 23.33, p = 0.071; 5.22 vs 18.66, p = 0.0146). C7-SVA was lower immediately and at 2yrs in 2A vs 3B (10.95 vs 26.05, p = 0.025; 7.24 vs 18.3, p = 0.01). No other differences were found between groups. Conclusions: Choosing the supine LTV when it touches at or medial to the pedicle is a viable strategy for LIV selection in AdIS. Having the preoperative CSVL lateral to the pedicle of the ultimate LIV in upright and particularly in supine films correlated with residual trunk shift and distance from CSVL to LIV. Josephine Coury 1 , Fthimnir Hassan 1 , Gabriella Greisberg 2 , Justin Reyes 1 , Alexandra Dionne 1 , Yong Shen 3 , Joseph Lombardi 1 , Zeeshan Sardar 1 , Ronald A. Lehman 1 , Lawrence Lenke 1 1 Columbia University Irving Medical Center, New York, United States , 2 Touro College of Osteopathic Medicine, New York, United States , 3 The Johns Hopkins Hospital, Baltimore, United States Introduction: Selecting the lower instrumented vertebra (LIV) in Adult Idiopathic Scoliosis (AdIS) fusion constructs poses challenges in achieving optimal alignment while minimizing fused motion segments. Previous research has demonstrated that failure to include the stable sagittal vertebra (SSV) within the construct can increase the incidence of postoperative malalignment and distal junctional kyphosis (DJK) in Adolescent Idiopathic Scoliosis (AIS). This study aimed to evaluate SSV on standing films and the impact of contact with LIV in the sagittal plane on outcomes in AdIS patients. Methods: This is a retrospective, single center case series of AdIS patients with fusion constructs ending proximal to the sacrum and minimum 2-year follow-up. Coronal and sagittal radiographic measurements were collected at baseline, immediately postop, at 6 months, 1 and 2 years postop, all on standing radiographs. Patients were categorized into 3 groups: grade 1) PSVL crossing in the anterior half of LIV, grade 2) PSVL crossing in the posterior half of LIV, and grade 3) crossing all posterior to LIV. Results: 55 AdIS patients were identified with average 2.6 year follow up (range 2-6), predominant coronal deformity (average major curve 57°, range 34°-136°), and LIV between T12 to L5. For all patients, C7-SVA improved from 22.95mm to 11.33 mm in 2 years (F = 9.58, p < 0.01). At 1 and 2 years, patients with LIV bisected by PSVL (grade 1 or 2) had a lower C7-SVA compared to grade 3 (7.5 mm and 7.65 mm vs 13.6 mm, F = 7.11, p = 0.01; 4.11 and 7.03 vs. 16.11, F = 12.36, p < 0.01). No difference was identified between grade 1 and 2 at any time point. No instances of distal adding on, distal junctional kyphosis, or subsequent revision surgery occurred. Conclusions: AdIS patients with a LIV bisected by PSVL, whether anterior or posterior, exhibited significantly lower C7-SVA at 1 and 2 years postoperatively compared to those where the LIV was untouched in the sagittal plane. Sarthak Mohanty 1 , Fthimnir Hassan 2 , LaRae Klarenbeek-Mitchell 3 , David Ruderman 3 , Eric Schaum 3 , Erik Lewerenz 2 , Zeeshan Sardar 2 , Joseph Lombardi 2 , Ronald A. Lehman 2 , Lawrence Lenke 2 1 Massachusetts General Hospital, Boston, United States , 2 Columbia University Irving Medical Center, New York, United States, 3 New York Presbyterian/Och Spine Hospital, New York, United States Introduction: Preoperative rehabilitation preceding adult spinal deformity (ASD) correction is associated with less postoperative disability. The impact of preoperative fitness on patients' presentation and subsequent outcomes remains unclear. The purpose of this study is to assess whether baseline functional fitness assessments can delineate distinct phenotypes within adult spinal deformity (ASD) patients and predict perioperative surgical complications post-correction. Methods: This is a retrospective, single surgeon cohort study of patients that underwent posterior spinal fusion (PSF) ≥ 8 levels and had sagittal deformity [pelvic incidence minus lumbar lordosis (PI-LL) ≥ 20°, T1 pelvic angle (T1PA) ≥ 20°, or C7 sagittal vertical axis (SVA) ≥ 4 cm]. Preoperative fitness was prospectively assessed through 6-Minute Walk Test (6MWT) and the Timed 5 time Sit-to-Stand Test (5xSTST). Fuzzy K-means machine learning clustering algorithm categorized patients into three fitness-based clusters (ordered from worst to best): Deconditioned, Intermediate, and Strongly Conditioned. The primary outcome was the difference in 90-day (90D) medical readmission rates. Secondary outcomes included the length of hospital stay (LOS) and intra-operative complications. An exploratory analysis was conducted to compare Oswestry Disability Index (ODI) sub-domains in 75 patients with baseline and two-year ODI scores. Clusters were compared using Tukey’s post-hoc test following ANOVA with data presented as: [worst vs intermediate vs best fitness, p-value (ANOVA or Chi-Square)]. Multivariable logistic and linear regression models assessed the impact of preoperative fitness on 90D medical readmissions and two-year ODI scores respectively after adjusting for demographics, medical comorbidities, preoperative alignment, pelvic fixation, and total instrumented levels. Results: 108 patients (32 Deconditioned, 40 Intermediate, 32 Strongly Conditioned) were included. Age (p = 0.1923), gender (p = 0.5543), instrumented levels (p = 0.9714), pelvic fixation (p = 0.1397), preop T1 pelvic angle (T1PA) (p = 0.9470), and SVA (p = 0.4893) were comparable across cohorts. Patients with the best conditioning had the lowest systolic blood pressure (SBP) (130.6 mmHg vs 126.0 mmHg vs 119.8 mmHg; p = 0.0002), shortest 5xSTST (12.71s vs 11.5s vs 8.9s; p = 0.0035), highest speed during 6 MWT (1.23 m/s vs 1.69 m/s vs 2.15 m/s; p = 0.0103) and walked the farthest (1331.1 ft vs 1659.95 ft vs 1771.22 ft; p < 0.0001). While LOS was similar across cohorts (6.44 vs 6.95 vs 6.11 days; p = 0.2697), intraoperative complication rates decreased with increasing fitness levels (50% vs 25% vs 11.11%, p = 0.0015). 90 D readmission was also lowest among patients with the best preop conditioning (37.5% vs 18.18% vs 11.11%; p = 0.0014). Multivariable analysis demonstrated that patients with the strongest preop conditioning [OR: 0.17, 95% CI: 0.04.55, p = 0.0054)] had significantly lower odds of 90D readmissions compared to deconditioned patients. In the exploratory analysis, preop ODI was significantly better with improved fitness (43.83 vs 34.0 vs 26.0; p < 0.0001) with significant differences in all ODI domains aside from sleeping and standing. Two-year ODI scores were superior in patients with best baseline fitness (23 vs 25.4 vs 12.5; p = 0.0005). In the multivariable model, strong preoperative conditioning (relative to deconditioned status) was an independent driver of two-year ODI scores [Beta: -14.32, 95% CI: -21.78- -6.86, p = 0.0003]. Conclusions: Baseline functional fitness profiling in adult spinal deformity patients offers a predictive value for postoperative complications and outcomes. Better preoperative fitness is associated with lower intra-operative complication rates, lower early readmissions, and better two-year ODI scores. Viprav Raju 1 , Anjishu Banerjee 1 , Yin Li 2 , Aditya Vedantam 1 1 Medical College of Wisconsin, Neurosurgery, Milwaukee, United States , 2 University of Wisconsin-Madison, Madison, United States Introduction: Degenerative Cervical Myelopathy (DCM) is a progressive condition characterized by spinal cord compression leading to impaired hand dexterity and balance. Delays in diagnosis are common in DCM leading to delays in surgical intervention and poorer outcomes. Lack of objective diagnostic tools contribute to delays in diagnosis and is an unmet clinical need for DCM. In this study, we tested a novel smartphone-based computer vision tool to detect hand and balance impairment in DCM. Materials and Methods: We collected smartphone video recordings from DCM patients and healthy controls (HC) performing a 10-second grip and release test for hand dexterity and a 10-second stepping task for postural stability. The grip and release test involved analyzing metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joint angles to assess release (maximum extension) and grip (minimum flexion) positions. For the stepping task, we evaluated maximum knee and hip flexion angles, trunk tilt, and the rate of change of joint angles. MediaPipe markerless tracking software was used to measure joint angles and their rates, calculated in degrees per frame. Statistical comparisons were made between the DCM and HC groups using the Mann-Whitney U tests. Results: Thirty-four participants- 17 DCM patients (mean age 63.4 ± 11.3 years; 9 males) and 17 HCs (mean age 60.2 ± 13.4 years; 8 males) were recruited. In the grip and release test, DCM patients showed significantly lower release joint angles for the index finger MCP (163.64° in DCM vs. 176.71° in HC; p < 0.001) and index PIP (174.66° in DCM vs. 176.49° in HC; p < 0.001), indicating a reduced range of finger extension. The DCM group also had higher grip angles for index finger MCP (158.04° in DCM vs. 154.98° in HC; p < 0.405) and with significantly higher angles for index PIP (7.99° in DCM vs. 5.08° in HC; p < 0.001), indicating altered finger motion during gripping. Additionally, DCM patients exhibited slower rate of change of joint angles during the grip and release tasks- index MCP (1.20°/frame in DCM vs. 1.32°/frame in HC; p < 0.05) and index PIP (7.01°/frame in DCM vs. 8.12°/frame in HC; p < 0.05). For the stepping task, DCM patients demonstrated a significantly lower maximum right knee angle (82.35° in DCM vs. 95.82° in HC; p = 0.044), and maximum left hip angle (71.91° in DCM vs. 82.34° in HC; p < 0.001).Additionally, median rates of change of joint angles were significantly lower in the DCM group compared to the HC group for left knee (1.72°/frame in DCM vs. 4.24°/frame in HC; p < 0.001), right knee (1.28°/frame in DCM vs. 2.86°/frame in HC; p = 0.043), left hip (1.01°/frame in DCM vs. 2.74°/frame in HC; p < 0.001), and right hip (1.19°/frame in DCM vs. 4.00°/frame in HC; p < 0.001). A greater trunk tilt was observed in DCM (10.26° in DCM vs. 5.79° in HC; p < 0.001). Conclusion: We demonstrate the utility of a smartphone-based computer vision tool to detect DCM-specific impairments in finger motion and postural stability in the clinic. These results demonstrate a promising objective tool for the early detection of subtle motor deficits in DCM, potentially reducing delays in diagnosis for DCM. Marcos Vaz de Lima 1,2 , Claudio Santili 1 , Maria Fernanda Silber Caffaro 1 , Robert Watkins 3 1 Santa Casa de São Paulo, São Paulo, Brazil , 2 Instituto Tecnológico de Aeronáutica - ITA, São José dos Campos, Brazil , 3 Watkins Spine, Los Angeles, United States Introduction: Spondylolysis, a lytic lesion affecting the pars interarticularis of the lumbar vertebrae, is commonly found in athletes due to repetitive stress during sports activities. This condition, if untreated, may lead to spondylolisthesis, where a vertebra slips anteriorly. The incidence of low back pain in athletes can reach up to 86%, with spondylolysis being a significant contributor in 60% of cases. The aim of this study is to provide an updated review of the diagnosis and treatment of spondylolysis and spondylolisthesis in athletes, based on clinical experience and literature review. Methods: This study reviews the epidemiology, clinical diagnosis, imaging, risk factors, and treatment options for spondylolysis and spondylolisthesis. Data from various sports disciplines are examined, including the prevalence of these conditions among athletes in high-impact sports such as hockey, tennis, diving, and rugby. Results: The incidence of spondylolysis is notably high in athletes, with some sports showing a prevalence of up to 44%. Diagnostic imaging, including radiography, CT, and MRI, plays a crucial role in the detection and classification of spondylolysis and spondylolisthesis. Conservative treatment, consisting of rest and rehabilitation, is generally effective, although surgical intervention may be required for athletes who do not respond to conservative measures within six months. Discussion: Spondylolysis and spondylolisthesis are common in athletes who engage in repetitive flexion-extension and rotation movements of the spine. Early diagnosis is critical in preventing progression to spondylolisthesis and ensuring a successful return to sports. Imaging techniques have evolved, with MRI now playing a central role in early diagnosis. For cases refractory to conservative treatment, surgical options, including direct pars repair and arthrodesis, have shown promising outcomes, with athletes returning to pre-injury performance levels in up to 90% of cases. Conclusion: Spondylolysis and spondylolisthesis in athletes require a comprehensive approach to diagnosis and treatment. Early identification, appropriate imaging, and tailored treatment plans are essential to minimize downtime and prevent long-term complications. Future advancements in minimally invasive surgical techniques may further improve recovery times and outcomes for affected athletes. Vivek Shankar 1 , Nitish Jagdish 1 , Swayam Dash 1 , Venkatesan Kumar 1 , Vijay Kumar 1 , Rishi Madan 2 1 All India Institute of Medical Sciences, Orthopaedics, New Delhi, India , 2 AIIMS, Orthopaedics, New Delhi, India Introduction: Foot drop can result from a central spinal pathology or a peripheral peroneal neuropathy. This diverse origin presents a diagnostic enigma in physical trainers who often engage in strenuous weightlifting and intense strength training, with lumbosacral radiculopathy (due to herniated disc or foraminal stenosis) being a more common cause. We present a case of Slimmer’s paralysis in a young male who experienced right-sided foot drop following rapid weight changes and to highlight the diagnostic challenges between lumbosacral plexopathy/radiculopathy and common peroneal neuropathy. Slimmer’s paralysis is a peripheral mononeuropathy of the common peroneal nerve (CPN), typically associated with rapid weight loss resulting in loss of subcutaneous fat-pad and subsequent neural compression at the fibular head. Material and Methods: It is a case report on a young male with a 1-year history of right-sided foot drop, preceded by rapid weight gain over 2 days due to binge eating followed by intentional weight loss of 11kg in 15 days (equivalent to 13% of body weight reduction (0.73 kg/day) from his baseline weight of 84 kg). Laboratory tests for systemic/metabolic disorders, radiology of the lumbosacral spine and electrophysiological studies were conducted. Confounding factors included high-intensity training, frequent squatting, and stretching. Results: Inflammatory markers and metabolic screening tests were within normal limits and tests for connective tissue disorders were negative. The radiographs of the lumbosacral spine and lower limb were normal. Motor nerve conduction studies (NCS) displayed non-recordable latency, amplitude, and velocity in the right peroneal nerve, F waves were non-recordable. Sensory NCS was normal. Electromyography (EMG) showed denervation changes. Conclusion: This case underscores the diagnostic dilemma between lumbosacral plexopathy/radiculopathy and common peroneal neuropathy. Persistent denervation on electrophysiological studies suggest that surgical decompression has no role, emphasizing the need for tendon transfer. Muhamad Aulia Rahman 1 , Hidenori Matsuoka 2 , Michihisa Narikiyo 2 , So Ohashi 2 , Renindra Ananda Aman Nanda 3 , Setyo Nugroho 3 1 Primaya Hospital, Spine Department, Neurosurgery Department, Bekasi, Indonesia , 2 Kawasaki Saiwai Hospital, Spine Department, Kawasaki, Japan , 3 Universitas Indonesia, Neurosurgery Department, Jakarta, Indonesia Introduction: We present a case study of epidural contrast visualization during lumbar discography. Material and Methods: A 58-year-old male was admitted to Kawasaki Saiwai Hospital with intermittent claudication and pain in the left leg. Magnetic Resonance Imaging (MRI) showed canal and foraminal stenosis resulting from disc herniation in the paracentral region of the L5-S1 vertebrae. The patient subsequently underwent Percutaneous Endoscopic Discectomy (PED), which was preceded by discography. Discography was performed under general anesthesia on the left side immediately before PED using a Chiba Needle (gauge and length). The injection substance was a mixture of 2,5 cc Indigo Carmine (Daiichi Sankyo) and contrast (Omnipaque, GE Health Care Pharma). The injection point was pointed using 1/3 anterior portion of the disc space in oblique 45 °fluoroscopy and slightly tilted cranially (following the disc space) until we obtained a true oblique picture to enter the L5-S1 disc space due to the presence of the iliac crest at the L5-S1 level. After we found the projection trajectory in the skin, we touched the disc surface with a Chiba needle in the orthogonal direction with fluoroscopy confirmation and continued to enter the disc space a little, changing the fluoroscopy to the lateral position to obtain a depth confirmation. Contrast concoction injection was performed and checked using fluoroscopy. Contrast concoction was found inside the disc and epidural spaces (between the posterior longitudinal ligament {PLL} and dural sac). An anteroposterior (AP) view was performed, which revealed contrast following the S1 left root. Results: Discography was first performed in 1941 by Swedish radiologist Lindblom by injecting a red lead contrast into a cadaveric disc. In the 1995 The North American Spine Society (NASS) recommended the use of discogram for persistent back pain, negative imaging findings, suspected intervertebral disc abnormality, and being considered to spinal fusion surgery. In addition to discography as a diagnostic tool, discography with Indigo Carmine is also used to assist minimally invasive spine surgery, and is called chromodiscography. Indigo carmine with contrast dye was used for material injection. Indigo carmine accumulates in the degenerative nucleus pulposus as a contrast stain and helps remove the disc. Normally, during discography, the contrast material will enter only the disc space, but we found that a type of new-onset transligamentous disc herniation can lead to contrast appearance in the epidural space and go through the foramen. PLL is a structure that hold the integrity and flexibility of the vertebral body from the posterior side.4 This feature hold the herniated disc if the direction is in the central or paracentral. PLL width varies from to 2-2,25 mm at the L5-S1 level. PLL is attached to the edge of the vertebral body and annulus fibrosus. The disruption of PLL attachment due to transligamentous disc herniation is suspected to result in contrast in the epidural space. Conclusion: Epidural contrast appearance during discography is a sign of connection between the disc space and epidural space through transligamentous herniation and not a sign of a false route in discography. David Van Schaik 1 , Lisa Goudman 2,3 , Tjeerd Jager 1 , Maarten Moens 2,4,5 , Thierry Scheerlinck 1 1 Free University of Brussels, Orthopaedics and Traumatology, Brussels, Belgium , 2 Free University of Brussels, Stimulus Research Group, Brussels, Belgium , 3 Research Foundation - Flanders, Brussels, Belgium , 4 Faculty of Physical Education and Physiotherapy, Free University of Brussels, Pain in Motion (PAIN) Research Group, Department of Physiotherapy, Human Physiology and Anatomy, Brussels, Belgium , 5 Universitair Ziekenhuis Brussel, Radiology, Brussels, Belgium Introduction: Sexual health is rarely discussed in a public healthcare context. Patients' barriers to discussing sexual health are the taboo nature of the topic and the inappropriateness of visit conditions, while neurosurgeons cite the patient's age, lack of knowledge, and lack of initiative from patients to bring up the subject as the main barriers. Therefore, the aim of this study is to further explore to what extent influencing factors can alter the discussion about sexual health. More specifically, we will evaluate the influence of healthcare profession, the sex of the patient, and the proposed surgical approach. Material and Methods: An online survey was sent to neurosurgeons, anesthesiologists, and orthopedists in Belgium and The Netherlands in April 2019. Participants were asked about their counseling routine, knowledge, and opinions on sexual health in spinal care. Answers were scored on a 5-point Likert scale. To test for independence between the response levels on the one hand and type of surgery and profession on the other, likelihood-ratio chi-squared tests were used to compare the expected frequencies with the observed frequencies. Results: In total, 350 respondents were approached, of whom 57 completed the survey. The majority of respondents (61.4%) indicated that they rarely or never discussed sexual disturbances. Communication on sexual disturbances was independent of profession. Both before and after surgery, there were more anesthesiologists who never asked about sexual functionality than expected under independence. For ALIF procedures, more physicians discussed sexual functionality than expected. Profession and type of surgery influenced discussions on erectile dysfunction, retrograde ejaculation, and alterations in orgasms, but not on disturbed lubrication. Thirty-five percent of healthcare providers considered it the patient's responsibility to bring up the subject of sexual health. Conclusion: Sexual health is rarely addressed by healthcare providers during spinal care. The profession of the healthcare provider and the type of surgery seem to play a role in whether sexual health is discussed during consultations, strongly advocating for standardization in sexual health counseling during spinal care. Omar Diaz 1 , Michael Dittmar 1 1 Hospital Puerta de Hierro, Guadalajara, Mexico Introduction: Sagittal balance of the spine is the key to understanding the fundamental biomechanics of spinal pathologies, especially during aging. The sagittal vertical axis (SVA) is a commonly used method to quantify sagittal balance. The vertical sagittal axis is measured by the distance between a vertical plumb line from C7 to the superior posterior corner of S1. Its calculation is done through a panoramic x-ray of the spine in a lateral position. This x-ray is sometimes difficult to obtain, whether is not available in the different hospitals or primary care units or the cost is very high. Material and Methods: We propose a non-radiological method to determine sagittal balance and compare it with the traditional method of panoramic x-rays. All patients in the medical consult will be included, they will be classified by age and sex. A vertical plumb line measurement will be made from the external auditory canal in relation to the midpoint of the femoral trochanter to determine if there is positive or negative sagittal balance. We measured the distance from the plumb line to the femoral greater trochanter and observed the relationship with the panoramic radiograph and the sagittal imbalance. We compared both methods. Results: We included 10 patients of different ages, 5 men and 5 women. First, we measured the distance of the vertical plumb line to the femoral trochanter and then we compared it with the measurements carried out on the x-rays. We observed non-significant variation to determine whether the balance was positive or negative. Conclusion: The proposed clinical method helps to obtain sagittal balance parameters with similar outcomes without the need to perform panoramic x-rays, which are non-standardized studies in all radiology centers, in addition, they have a much higher cost than conventional radiographs. Mthunzi Ngcelwane 1 , Shaheed Vally Omar 2 , Meshack Bida 3 , Mohamed Said 4 1 University of Pretoria, Orthopaedics, Pretoria, South Africa , 2 National Institute for Communicable Diseases, Johannesburg, South Africa , 3 Department of Anatomical Pathology, Pretoria, South Africa , 4 Department of Medical Microbiology, University of Pretoria, Pretoria, South Africa Introduction: The workstream for the diagnosis of tuberculosis (TB) involves isolation and culture of the organism and drug resistance testing using phenotypic methods. Xpert MTB/RIF Ultra is a genetic-based method that detects for Mycobacterium tuberculosis DNA in the rpoB gene. Whole Genome Sequencing (WGS) is a newer genetic-based method that assesses the whole genome of the bacterium. Very few studies have reported the use of WGS in extrapulmonary TB. The aim of the study was to evaluate the utility of WGS in drug resistance testing, lineage of the organisms, and organism-related factors responsible for bacilli settling in the spine. Material and Methods: Tissues from 61 patients undergoing TB spine surgery underwent histologic examination, Xpert MTB/RIF Ultra, and culture and sensitivity testing. DNA from the cultured bacteria was sent for WGS. The test bacterial genome was compared to a reference strain of pulmonary TB. Results: Acid-fast bacilli were observed in 9/58 specimens. Histology confirmed TB in all the patients. Bacilli were cultured in 28 patients (48.3%), and the average time to culture was 18.7 days. Xpert MTB/RIF Ultra was positive in 47 patients (85%). WGS was performed in 23 specimens. 45% of the strains belonged to lineage 2. There was one case of multidrug-resistant TB and two cases of non-tuberculous mycobacteria. We could not confirm any genomic difference between pulmonary and spine strains. Conclusion: WGS can diagnose multidrug-resistant TB and non-tuberculous mycobacteria more accurately. No mutations were identified responsible for spine TB. Paul Köhli 1,2 , Ali Guven 1 , Jan Hambrecht 1 , Erika Chiapparelli 1 , Lukas Schönnagel 2 , Gisberto Evangelisti 1 , Krizia Amoroso 1 , Roland Duculan 3 , Jennifer Shue 1 , Koki Tsuchiya 1 , Marco Burkhard 1 , Carol Mancuso 1 , Andrew Sama 1 , Federico Girardi 1 , Frank Cammisa 1 , Alexander Hughes 1 1 Hospital for Special Surgery, Department of Orthopaedic Surgery, New York, United States , 2 Charité Universitätsmedizin Berlin, Center for Muskuloskeletal Surgery, Berlin, Germany , 3 Hospital for Special Surgery, New York, United States Introduction: Identifying patients with impaired bone quality before lumbar surgery is essential for personalized treatment, including antiosteoporotic therapy, to reduce mechanical complications in spine surgery. One emerging screening tool for detecting osteoporosis or osteopenia is the T1 MRI-derived vertebral bone quality (VBQ) score, which measures the mean intensity of circular regions of interest (ROI) in the L1-4 vertebrae, normalized to CSF intensity. A VBQ measured only in L1 and L2 could provide faster assessment and would be suitable for patients with prior fusions or Modic changes in the lower lumbar spine. Materials and Methods: A secondary analysis of a prospective study involving patients undergoing lumbar surgery for degenerative spondylolisthesis at L4/5 was performed. Patients without preoperative thin-slice CT or sufficient MRI for VBQ measurements were excluded. VBQ L1-2 was measured by placing circular ROIs in the L1 and L2 vertebrae body on mid-sagittal T1-weighted images of the. For VBQ L1-4 , the circular ROIs were placed in the vertebral bodies of L1 through L4. Both measurements were normalized by dividing the mean intensities of ROIs L1-2 respective L1-4 by the intensity of the cerebrospinal fluid at the L2/3 level. BMD was assessed using opportunistic qCT per American College of Radiology guidelines, with osteoporosis defined as BMD < 80 mg/cm 3 and impaired bone quality (osteoporosis or osteopenia) as BMD < 120 mg/cm 3 . Descriptive and comparative statistics were performed, and the Intraclass Correlation Coefficient (ICC) for agreement between VBQ L1-2 and VBQ L1-4 was calculated. ROC analysis with Youden index optimization was conducted to evaluate the predictive performance of both VBQ versions for osteoporosis and impaired bone quality. Results: A total of 144 patients (median age 69 years, inter quartile range 64-73, 39% male) were included. The prevalence of osteopenia was 47% (68/144) and osteoporosis was 22% (31/144), resulting in 69% (99/144) of patients exhibiting impaired bone quality. The ICC between VBQ L1-2 and VBQ L1-4 was 0.988 (95% CI: 0.982-0.991). ROC analysis showed that VBQ L1-2 had an AUC of 0.71 for predicting osteoporosis (Cut-off: 2.30, Sensitivity: 94%, Specificity: 45%), while VBQ L1-4 had an AUC of 0.68 (Cut-off: 2.55, Sensitivity: 74%, Specificity: 61%). For predicting impaired bone quality, VBQ L1-2 had an AUC of 0.68 (Cut-off: 2.26, Sensitivity: 77%, Specificity: 56%), and VBQ L1-4 had an AUC of 0.67 (Cut-off: 2.69, Sensitivity: 47%, Specificity: 82%). Conclusion: The VBQ L1-2 showed excellent agreement with the classic VBQ L1-4 , and the predictability of the VBQ L1-2 to detect osteoporosis or osteopenia was not lower than that of the VBQ L1-4 . The VBQ L1-2 may offer a faster and more broadly applicable alternative, facilitating the wider use of MRI-based bone quality screening. However, further, larger studies are needed to explore the relationship between VBQ L1-2 and BMD in different patient populations, and to establish optimal cutoffs and applications. Chao-Yuan Ge 1 , Wen-Long Yang 1 , Zheng-Wei Xu 1 , Ding-Jun Hao 1 1 Honghui Hospital, Xi’an Jiaotong University, Xi’an, China Introduction: At present, the surgical options for multi-level lumbar degeneration remain controversial. The aim of this study is to explore the guiding value of ultrasound-guided selective nerve root block (SNRB) in surgical treatment decision making in patients with multi-level lumbar degenerative diseases. Material and Methods: A retrospective analysis was performed on 90 patients with multi-level lumbar degenerative disease who were surgically treated in our hospital from January 2019 to October 2022. The patients were divided into SNRB group and non-SNRB group according to whether or not they underwent SNRB before surgery. There were 48 patients in the SNRB group. Their responsible segments were identified by ultrasound-guided SNRB, combined with symptoms and imaging examination before surgery. Then decompression was performed on the responsible segments. A total of 42 patients in the non-SNRB group, and conventional multi-level lumbar spinal canal decompression was performed because their responsible segments were not clear. The operative time, intraoperative blood loss, the VAS score and JOA score of lumbar and leg pain before surgery, the 3rd day after surgery, 6 months after surgery, and the last follow-up were recorded and compared between the two groups, and the occurrence of intra-operative complications were also recorded. Results: The operation was successfully completed in both groups, and no serious complications occurred during surgery. One case of dural tear occurred in the non-SNRB group and was repaired intraoperatively. The operative time and blood loss in SNRB group were significantly less than those in non-SNRB group (p < 0.05). The VAS scores and JOA scores of low back pain and leg pain in SNRB group were better than those in the non-SNRB group on the 3rd day after surgery, 6 months after surgery and at the last follow-up, with statistical significance (p < 0.05). No loosening, or displacement of the instrumentation were found in the two groups, and the bone grafting healed well. Conclusion: This study showed that preoperative ultrasound-guided SNRB could identify the responsible segments and provide surgical guiding value for patients with multi-level lumbar degeneration. Ahmad Kareem Almekkawi 1 , James P. Caruso 2 , Angela Hawkins 1 , Rayaan Rauf 3 , Mayar Al-Shaikhli 3 , Salah Aoun 4 , Carlos Bagley 1 1 Saint Luke's Hospital, Neurosurgery, Kansas City, United States , 2 NYU Langone, Orthopedic Surgery, New York, United States , 3 University of Missouri - Kansas City, School of Medicine, Kansas City, United States , 4 UT Southwestern, Neurosurgery, Dallas, United States Introduction: This study aimed to investigate the accuracy of large language models (LLMs), specifically ChatGPT and Claude, in surgical decision-making and radiological assessment for spine pathologies compared to experienced spine surgeons. Material and Methods: The study employed a comparative analysis between the LLMs and a panel of attending spine surgeons. Five written clinical scenarios encompassing various spine pathologies were presented to the LLMs and surgeons, who provided recommended surgical treatment plans. Additionally, MRI images depicting spine pathologies were analyzed by the LLMs and surgeons to assess their radiological interpretation abilities. Spino-pelvic parameters were estimated from a scoliosis radiograph by the LLMs. Results: Qualitative content analysis revealed limitations in the LLMs' consideration of patient-specific factors and the breadth of treatment options. Both ChatGPT and Claude provided detailed descriptions of MRI findings but differed from the surgeons in terms of specific levels and severity of pathologies. The LLMs acknowledged the limitations of accurately measuring spino-pelvic parameters without specialized tools. The accuracy of surgical decision-making for the LLMs (20%) was lower than that of the attending surgeons (100%). Statistical analysis showed no significant differences in accuracy between the groups. Conclusion: The study highlights the potential of LLMs in assisting with radiological interpretation and surgical decision-making in spine surgery. However, the current limitations, such as the lack of consideration for patient-specific factors and inaccuracies in treatment recommendations, emphasize the need for further refinement and validation of these AI models. Continued collaboration between AI researchers and clinical experts is crucial to address these challenges and realize the full potential of AI in spine surgery. Haolin Sun 1 , Xueyuan Su 2 1 Peking University First Hospital, Beijing, China , 2 Peking University First Hospital Taiyuan, Taiyuan, China Introduction: This study introduces the key points of clinical diagnosis and treatment of fungal infections of the spine through a combination of case report and literature review. Material and Methods: The case reported is a 52-year-old female patient with moderate to severe lower back pain for 7 months, accompanied by intermittent fever (Tmax: 40°C). Laboratory tests revealed varying degrees of elevated white blood cell count, erythrocyte sedimentation rate, C-reactive protein, and procalcitonin. Imaging studies, including lumbar X-ray, CT, and MRI, showed progressive disc space collapse and subendplate bone destruction at the L4/5 segment, along with localized kyphotic deformity. Despite intermittent bed rest, lumbar bracing, and empirical antibiotic therapy (vancomycin + imipenem for 2 weeks, followed by linezolid for 10 weeks), there was no clinical improvement. The patient underwent minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) at L4-5 via a transforaminal approach, with debridement, interbody grafting, and pedicle screw fixation. Postoperative culture results indicated Scedosporium species. Antifungal therapy with voriconazole was administered postoperatively. Results: At the 6-month follow-up, the patient's clinical symptoms significantly improved, and laboratory markers returned to normal. Follow-up CT and MRI of the lumbar spine showed significant control of the infection. The literature review focuses on the clinical features, imaging characteristics, treatment methods, and outcomes of spinal fungal infections in the past five years. Conclusion: Fungal infections of the spine have an insidious onset. Early identification of the pathogen and regular antifungal treatment are essential. Surgical debridement and stabilization of the affected vertebrae can effectively help control the infection. Sami Bahroun 1 , Masmoudi Zied 1 , Mohamed Samih Kacem 1 , Anis Bouaziz 1 , Mohamed Samir Daghfous 1 1 Kassab Hspital, Orthopaedic Department B, Tunis, Tunisia Introduction: Adolescents are not exempt from experiencing low back pain, as their growing spines are subject to various mechanical stresses. We present a series of 15 cases of common low back pain in individuals under 18 years old, in which we outline the clinical, radiological, and progression characteristics of low back pain. Material and Methods: This retrospective study spans three years (2020-2023) and includes 15 patients (6 girls and 9 boys) aged 14 to 18. Patients were referred from rheumatology, pediatric orthopedics, or physical medicine consultations. Each patient underwent a detailed history, covering the onset of symptoms and potential triggers, complete physical examination, and standard radiological assessment. Treatment approaches and patient outcomes were also documented. Results: The delay between symptom onset and consultation varied from 2 months to 2 years. A traumatic trigger was identified in 9 cases, with 6 of these linked to sports-related injuries. Clinical findings included significant spinal syndrome in 10 patients, muscle contracture in 8, and positive provocation test in 6 patients. Neurological exams were normal in all patients. Radiological assessments revealed discopathy in 4 cases, and signs of Scheuermann’s disease in 4 others. In 5 children, a bone lesion was suspected, but bone scintigraphy was normal. Of the 3 patients who underwent MRI, 2 had normal results, while 1 showed discopathy with disc herniation and an enlarged dural sac. Treatment consisted of medication, including analgesics, NSAIDs, and muscle relaxants, with short-term corticosteroids added for 3 patients. Physical therapy was administered to 8 patients. Back pain resolved in 9 patients after an average follow-up period of 12 months (ranging from 4 to 36 months). Pain persisted in 3 patients. While 3 patients were lost to follow-up. Conclusion: Though the sample size is small, it shows that low back pain in adolescents can be indicative of an underlying condition. Before attributing symptoms to growth-related pain, conditions such as disc herniation and tumors should be ruled out. Joydeep Baidya 1 , Jonathan Dalton 1 , Olivia Opara 1 , Rajkishen Narayanan 1 , Alec Giakas 1 , Yunsoo Lee 1 , Jeremy Heard 1 , Lauren Micou 1 , Thomas Swiderski 1 , Nicholas Yeo 1 , Jose Canseco 1 , Alan Hilibrand 1 , Alex Vaccaro 1 , Chris Kepler 1 , Gregory Schroeder 1 1 Rothman Orthopaedic Institute, Philadelphia, United States Introduction: Postoperative fluid collections can be a common occurrence following spine surgery, with the incidence of asymptomatic collections reaching as high as 89%. These may spontaneously resorb within a few months of surgery without significant impacts on patient symptoms or outcomes. Symptomatic postoperative fluid collections, on the other hand, can cause neurologic compromise or radicular pain resulting from mass effect and mechanical compression of neural elements. While their incidence is relatively low, the outcomes of delayed treatment can be catastrophic, including cauda equina syndrome and paralysis. When suspected, MRI is the preferred modality of diagnostic imaging. Prompt imaging is crucial as surgical evacuation and decompression has been associated with improved neurologic outcomes. However, the presenting symptoms of patients that may contribute to findings of compressive fluid collections on MRI have yet to be elucidated. As such, the current study aimed to examine the relationship between presenting symptomatology and radiologic findings on MRI, as well as characterize subsequent management and outcomes. Material and Methods: Patients > 18 years of age who underwent posterior cervical decompression and fusion (PCDF) or lumbar fusion at a tertiary care center from 2017-2022 and had an MRI within 14 days following surgery were retrospectively reviewed. Those undergoing surgery for trauma, tumor, infection, revision, or using anterior approaches were excluded. Demographic and surgical characteristics including age, sex, race, BMI, smoking status, diabetes, Charlson Comorbidity Index, length of stay, OR time, estimated blood loss, and number of levels fused/decompressed were collected. Outcomes of interest were indications for undergoing MRI stratified into numbness/pain and neurologic deficit/weakness; presence of fluid collection on MRI; surgical drain characteristics including time, number, and output; and subsequent treatment, symptomatic improvement, readmission within 2 weeks, surgical complications, and discharge disposition. P-value < 0.05 was considered to be the threshold for statistical significance. Results: A total of 58 patients who met inclusion criteria were included. Of these, 15 patients underwent MRI for numbness/pain while 43 underwent it for neurologic deficit/weakness. There were no differences between the groups with regards to demographic or surgical characteristics. The presence of fluid collection with or without neural compression; all surgical drain characteristics; incidence of operative versus nonoperative treatment, symptomatic improvement, 2-week readmission, and surgical complications; and discharge disposition were similar between groups. When the cohort was stratified based on the presence of fluid collection, as well as subgroup analysis performed on patients with evidence of fluid collection with neural compression on MRI, all outcomes of interest continued to be comparable between groups. Conclusion: The current study found no association between presenting symptomatology and patients’ demographic or surgical characteristics. Symptomatology was also not associated with fluid collection findings on MRI, type of treatment utilized, or rates of improvement and subsequent outcomes. Further research should focus on identifying other, more granular aspects of patient presentation that may indicate the need to evaluate for postoperative fluid collection, and possible return to the OR. Elyette Lugo 1 , Gabriel Nazario-Ferrer 1 , Eleanor Farris 1 , Amit Jain 1 1 Johns Hopkins, Orthopaedic Surgery, Baltimore, United States Introduction: Anterior cervical discectomy and fusion (ACDF) is a widely performed procedure for treating cervical spine disorders, including disc degeneration and spinal stenosis. Despite its prevalence, complications like dysphagia, wound infection, and pseudoarthrosis remain significant concerns. Achieving successful radiographic fusion is critical, as it correlates with long-term stability and symptom relief. However, the literature reports a wide discrepancy in fusion rates following ACDF, underscoring the need for a more reliable estimate. This study aims to provide a robust assessment of successful radiographic fusion rates using data from FDA Investigational Device Exemption (IDE) clinical trials to guide clinical decision-making and optimize patient outcomes. Material / Methods: A systematic review following PRISMA guidelines was conducted to identify FDA IDE clinical trials that evaluated radiographic fusion rates after ACDF. Eligible studies were those that included adult patients undergoing 1- or 2-level ACDF, utilized FDA-approved devices, and reported radiographic fusion outcomes. Data extracted included patient demographics, surgical details, radiographic fusion criteria, and follow-up intervals. Statistical analysis was performed using unpaired t-tests to compare fusion rates, with significance set at p ≤ 0.05. Results: Eleven FDA IDE clinical trials with 1,926 patients (84.8% undergoing 1-level ACDF and 15.2% undergoing 2-level ACDF) were included. Fusion was assessed using various criteria, including the presence of bridging bone and lack of motion on radiographs. The mean age was 44.6 years for 1-level ACDF patients and 46.8 years for 2-level patients. At 12 months, the weighted mean fusion rate for 1-level ACDF was 87.3%, increasing to 98.6% at 72 months. For 2-level ACDF, fusion rates ranged from 81.3% at 24 months to 91.6% at 84 months. Statistically significant differences were noted between 1-level and 2-level ACDF fusion rates at 24 and 84 months (p < 0.01). Only 7 studies further specified that less than 50% of the graft-vertebra should exhibit radiolucent lines and 6 studies set the cutoff at ≤ 2° for angular motion on flexion/extension radiographs. The fusion rate in these studies was 88% and 86%. Conclusion: This study provides a comprehensive analysis of radiographic fusion rates following ACDF, highlighting the variability in reported outcomes due to differing fusion assessment criteria. The findings underscore the need for standardized methods to reliably measure successful fusion, which would enhance clinical decision-making and improve long-term patient outcomes.

Siril Teja Dukkipati 1,2 , Mark Driscoll 1,2 1 Musculoskeletal Biomechanics Research Lab, Department of Mechanical Engineering, McGill University, Montreal, Canada , 2 Orthopaedic Research Laboratory, Research Institute MUHC, Montreal General Hospital, Montreal, Canada Introduction: Conventional finite-element based spine biomechanical models often adapt linear material properties and overlook the role of intra-abdominal pressure (IAP) in spinal load-sharing during flexion movements. Additionally, due to their inherent nature of solving for variables across the entire geometrical domain, these models tend to be computationally demanding, making them less suitable for high-fidelity applications such as muscle recruitment simulations and machine learning. This study aims to overcome these challenges by developing a novel validated, fast-solving high-fidelity musculoskeletal spine model that incorporates IAP while maintaining anatomical accuracy. Material and Methods: The model comprised of L1-S1 vertebrae, intervertebral discs, a lumped thoracic spine and ribcage, diaphragm, spinal muscle groups including the rectus abdominis, multifidus, and internal and external obliques, and spinal ligaments, specifically the supraspinous, interspinous, and intertransverse ligaments. The skeletal components were derived from 2mm 3D MRI scans of a healthy adult male, while the intervertebral discs were modeled as three-degree-of-freedom (3DOF) gimbal joints, with a custom torque feedback mechanism for joint control inclusive of damping to model joint hysteresis. The muscles were modeled as point-to-point tensile-only forces, and the ligaments as nonlinear tension-only springs. The IAP was modeled as normal force vectors acting on the spine and diaphragm with their magnitudes proportional to IAP (Method #1). Additionally, a novel alternative approach to model IAP was proposed, employing spring-damper elements within the abdominal cavity (Method #2). The model was assembled in MATLAB and had a total of 15 DOFs, controlled by 279 independent force-generating elements, providing a detailed and comprehensive representation of spinal anatomy. Thereafter, the model was subjected to 7.5Nm pure bending moments while fixing the sacrum to validate spinal stiffness. The extensor torque generated by the increase in IAP on the spine was used to validate the IAP models. Results: The model's L1-S1 segmental range of motion (ROM) under pure bending moments in flexion-extension, lateral bending (LB), and axial rotation (AR) demonstrated strong agreement with multiple ex vivo literature datasets with a maximum ROM of 16.05° in flexion and 16.03° in extension at 7.5 Nm, and an average ROM of 18.96° in LB and 12.38° in AR. The model observed distinct load-unload paths under sinusoidal moments displaying hysteresis, owing to the damping component in its joint implementation. A linear increase in extensor torque about the L3 vertebra at 50° trunk flexion was observed in the model with increase in IAP from 0.8Kpa to 3.3KPa (Method #1), aligning with in vivo measurements. The IAP method #2 also demonstrated an increased spinal stiffness (0.47-0.79Nm/deg) with increase in abdominal stiffness (0-1KN/m), agreeing with literature. The whole model compiled in 5.9 ± 0.13 sec and the average run time was 1.4 ± 0.03 sec. Conclusion: A fast-solving high-fidelity rigid body spine model inclusive of IAP was developed and validated against multiple in vivo data sets in various loading scenarios. The fast run time suggests that this model is suitable for iterative biomechanical problems like optimization and robotic control systems. This lightweight parametric simulation platform offers an intuitive tool to visualize physiological loads on the torso. Elie Najjar 1 , Ahmed Hassan 1,2 , Weronika Nocun 1 , Spyridon Komaitis 1 , Nasir Quraishi 1 1 Queen's Medical centre, Nottingham University Hospitals, Nottingham, United Kingdom , 2 Department of Orthopedics and Trauma Surgery, Assiut University School of Medicine, Assiut, Egypt Aims: Spinopelvic dissociation stands out as a challenging entity involving demanding decision-making and effective interdisciplinary communication. Multiple classification systems exist in the literature and mainly bank on morphological criteria for categorization. The current annotation aims to set foundations for a novel biomechanics-driven classification of spinopelvic-dissociation (SPD) injuries that can underpin the selection of optimal reduction techniques. Methods: Drawing upon pre-existing knowledge from traditional classification systems as well as expert opinion from our center, we devise a new classification for spinopelvic-dissociation type injuries. Results: Deformation forces leading to spinopelvic dissociation range from hyperflexion to vertical shear. The combination of forces in action, lumbopelvic biomechanics and anatomy, result on distinct fracture and displacement patterns. Recognizing the causative deformation vectors can help to extrapolate valuable information on the ideal reduction technique, ranging from extension manoeuvres for hyperflexion injuries to traction for vertical shear induced injuries. Conclusion: Conception of a new classification system for SPD is presented with the potential of driving decision-making related to reduction techniques. Ahmed Hassan 1,2 , Elie Najjar 1 , Mostafa Meshneb 1 , Anish Isapure 1 , Khalid Salem 1 , Weronika Nocun 1 , Nasir Quraishi 1 1 Queen's Medical Centre, Nottingham University Hospitals, Nottingham, United Kingdom , 2 Department of Orthopedics and Trauma Surgery, Assiut University School of Medicine, Assiut, Assiut, Egypt Background: The optimal treatment of traumatic thoracolumbar fractures (TLF) remains controversial. Both minimally invasive surgical techniques (MIS) using polyaxial screws and open surgery (OS) using Schanz screws has been widely used. The effect of each technique on the global sagittal alignment post operatively has not yet been reported. Study Design: a retrospective comparative cohort study. Purpose: To compare between the effects of MIS and OS in thoracolumbar fractures on global sagittal alignment. Methods: 22 patients with traumatic TLF underwent open posterior stabilization using open transpedicular Schanz screw-rod construct (OS) and were compared to 15 patients who underwent minimally invasive surgery (MIS) using percutaneous pedicle screws-rods construct. The reported radiological parameters measured on preop CT scan and immediate postop standing x-ray and final follow-up whole spine standing x-ray included: Pelvic incidence (PI), Pelvic Tilt (PT), Lumbar Lordosis (LL), Preoperative segmental kyphosis (Preop-K), immediate post operative segmental Kyphosis (postop-Ki), final post operative segmental kyphosis (postop-Kf), sagittal vertical axis (SVA) and spino-sacral angle (SSA). Results: The average age of the OS group was 42.5 years (17-76), 5 (22%) patients had AO type B and 17 (78%) patients had AO type A (A3 and A4) fractures. The average follow-up was 16.8 months. The average radiological parameters were as follows: PI = 54.9°, PI-LL = 3°, PT = 17.6°, preop-K = 16.2°, postop-Ki = 8.7°, final postop-Kf = 14.3°, SVA = 4.58 cm, SSA = 101.8°. The average age of the MIS group was 43.4 years (17-66), 5 (33%) patients had AO type B and 10 (66%) patients had AO type A fractures. The Average follow-up was 25 months. The average radiological parameters were as follows: PI= 51°, PI-LL = 8°, PT = 18°, preop-K = 18.4°, postop-Ki = 11.6°, postop-Kf = 14.3°, SVA = 6.4cm, SSA= 106°. Conclusion: Despite sagittal imbalance at final follow-up in patients with traumatic thoracolumbar fractures treated with either MIS or OS, there was no statistically significant difference between both groups in regard to correction of local kyphosis and global spine alignment parameters. Weishi Liang 1 , Yihan Yang 1 , Yong Hai 1 1 Beijing Chaoyang Hospital, Capital Medical University, Orthopedic Surgery, Beijing, China Introduction: Cervical hybrid surgery optimizes the use of cervical disc arthroplasty (CDA) and zero-profile (ZOP) devices in anterior cervical discectomy and fusion (ACDF) but lacks uniform combination and biomechanical standards, especially in revision surgery (RS). This study aimed to investigate the biomechanical characteristics of adjacent segments of the different hybrid RS constructs in ACDF RS. Material and Methods: An intact 3-dimensional finite element model generated a normal cervical spine (C2-T1). This model was modified to the primary C5-6 ACDF model. Three RS models were created to treat C4-5 adjacent segment degeneration through implanting cages plus plates (Cage-Cage), ZOP devices (ZOP-Cage), or Bryan discs (CDA-Cage). A 1.0-Nm moment was applied to the primary C5-6 ACDF model to generate total C2-T1 range of motions (ROMs). Subsequently, a displacement load was applied to all RS models to match the total C2-T1 ROMs of the primary ACDF model. Results: The ZOP-Cage model showed lower biomechanical responses including ROM, intradiscal pressure, maximum von Mises stress in discs, and facet joint force in adjacent segments compared to the Cage-Cage model. The CDA-Cage model exhibited the lowest bio mechanical responses and ROM ratio at adjacent segments among all RS models, closely approached or lower than those in the primary ACDF model in most motion directions. Additionally, the maximum von Mises stress on the C3-4 and C6-7 discs increased in the Cage-Cage and ZOP-Cage models but decreased in the CDA-Cage model when compared to the primary ACDF model. Conclusion: The CDA-Cage construct had the lowest biomechanical responses with mini mal kinematic change of adjacent segments. ZOP-Cage is the next best choice, especially if CDA is not suitable. This study provides a biomechanical reference for clinical hybrid RS decision-making to reduce the risk of ASD recurrence. Federico Landriel 1 , Jorge Rasmussen 2 , Fernando Padilla Lichtenberger 1 , Florencia Casto 1 , Tomas Saavedra Azcona 1 , Alfredo Guiroy 3 , Santiago Hem 1 1 Hospital Italiano de Buenos Aires, Spine Unit - Neurosurgery, Buenos Aires, Argentina , 2 Hospital Español, Neurosurgery, Mendoza, Argentina , 3 Clinica de Cuyo, Spine Unit - Neurosurgery, Mendoza, Argentina Introduction: Minimally invasive hemilaminectomy is a safe and effective alternative to open laminectomy for treating intradural extramedullary tumors. There are no reports of postoperative kyphosis after this approach. This study aims to determine whether performing minimally invasive spine surgery hemilaminectomy for intradural extramedullary tumors can prevent the development of postlaminectomy kyphosis (PLK) or lordosis loss. Material and Methods: Sixty-five patients with spinal intradural extramedullary tumors who underwent minimally invasive hemilaminectomy surgery and complete pre and postoperative radiologic imaging were included. The effect of the surgical approach on the spinal sagittal axis was assessed by comparing pre- versus postoperative segmental and local Cobb angles at different spinal levels, considering anatomical localization (cervical, thoracic, lumbar, and transition segments) and functional features (mobile, semi-rigid, and transition segments), as well as the extent of the surgical approach (1, 2, or 3 levels) and follow-up. Results: None of the patients had an increase in thoracic kyphosis nor a loss of cervical or lumbar lordosis greater than or equal to 10° after undergoing the minimally invasive spine surgery hemilaminectomy approach. More than 5° of increase in kyphosis was detected on 7.4% and 11.1%, for the segmental and the local angles, respectively; meanwhile, for patients with loss of lordosis, this deviation was detected in 5.3%, for both angles. The occurrence of PLK was more common than that of lordosis loss, but mainly manifested in postoperative angle impairment of less than 5°. No significant differences were evidenced, considering the approach length. Conclusion: Hemilaminectomy represents a promising approach for preventing PLK and postlaminectomy lordosis loss following intradural extramedullary tumor resection. Keywords: Hemilaminectomy; Postlaminectomy kyphosis; Postlaminectomy lordosis loss; Postoperative deformity; Postoperative kyphosis. Matthew Magro 1 , William Sheppard 2 , Colin Rhoads 3 , Arpan Patel 4 , Landon Reading 3 , Theodore Rudic 5 , Lauren Boden 5 , Jason Savage 5 , Michael Steinmetz 4 , Edin Navzeti 6 , Alex Spiessberger 4 1 Ohio University Heritage College of Osteopathic Medicine - Cleveland, Warrensville Heights, United States , 2 UCLA, Orthopedic Surgery, Los Angeles, United States , 3 Cleveland Clinic Foundation, Orthopedic Surgery, Warrensville Heights, United States , 4 Cleveland Clinic Foundation, Neurosurgery, Cleveland, United States , 5 Cleveland Clinic Foundation, Orthopedic Surgery, Cleveland, United States , 6 Denver Health Medical Center, Neurosurgery, Denver, United States Introduction: Pelvic fixation is a corner stone of multi-level spinal fusion constructs. Different fixation techniques have been established, including conventional iliac, S1-alar-iliac (S1ai), S2-alar-iliac (S2ai), and S3-alar-iliac (S3ai) fixation. The use of novel self-harvesting porous sacral-alar-iliac (SAI) screws with an integrated tulip in long spinal fusion constructs requiring bilateral SAI screw placement is becoming more popular Less is known about the biomechanical profile of such rigid pelvic fixation. We present a finite element analysis (FEA) evaluating the biomechanical impact of combined S1ai and S3ai pelvic fixation in comparison to other fixation methods. The results of this study have potential utility in clinical guidance and decision making, by matching the biomechanical properties of a fixation technique to the specific needs of a patient’s pathology. Material and Methods: Six L1-pelvis FEA spinal models were created comparing one noninstrumented control to 5 instrumented variants with pelvic fixation via: iliac bolt, S1ai, S2ai, S1ai + S3ai (8.5mm), and S1ai + S3ai (10.5mm). Interbody fusion was also modeled at L5-S1 in all instrumented variants. Loading conditions included flexion, axial-loading, and lateral bending at 100N, 200N, and 300N. Bony, discal and hardware related von Mises Stress (VMS) was calculated an analyzed for each variant and loading condition. Range of motion (ROM) was calculated for all motion segments. Results: The S1ai+S3ai large caliber screws (V6) demonstrated the lowest L5/S1 and L2/3 segmental mean ROM and provided the best pelvic stress shielding. Variant 3 (S1ai 8.5 mm x 80 mm screws) did not provide sufficient stability of a long fusion construct. Conclusion: This FEA reveals biomechanically significant differences with pelvis fixation in long spinal fusion constructs. Combined S1ai+S3ai large caliber pelvic screws outperformed all other fixation variants under investigation. In clinical practice we would expect lower hardware failure rates, superior stress shielding of the pelvis and possible improved kinematics at the cranial adjacent level. Devender Singh 1 , Matthew Geck 1 , John Stokes 1 , Eeric Truumees 1 , Vik Kohli 1 1 Ascension, Austin, United States Introduction: Spinal alignment is a critical factor in maintaining posture and reducing compensatory mechanisms, particularly in individuals with varying levels of pelvic incidence (PI). The interaction between PI, T1 Pelvic Angle (T1PA), and the cervical C2 plumbline is of paramount importance in achieving balanced spinal alignment. This study aims to explore how different combinations of these parameters influence spinal stability, providing insights into the optimal strategies for clinical spinal corrections. The study seeks to analyze the impact of varied PI, T1PA, and C2 plumbline configurations on spinal stability and alignment using data derived from 27 biomechanical models. It aims to identify the key radiographic parameters that determine optimal strategies for spinal correction across different PI categories. Methods and Materials: This study involved 27 biomechanical models representing various combinations of PI (high, medium, and low), target T1PA (10°, 15°), and adjustments to the C2 plumbline (through hips, 0°). Three corrective strategies were implemented for each model: PI-10 = Lumbar Lordosis (LL) (less curved), PI = LL (ideally curved), and PI+10 = LL (more curved). The data analyzed included key radiographic parameters such as T1 slope, PI-LL mismatch, and C2PL. Statistical methods including trend analysis, ANOVA, and cluster analysis were employed to discern significant differences and patterns across these strategies. Results: One of the corrective strategies consistently resulted in higher T1 slope values across all PI groups, indicating potential alignment issues, while another strategy showed lower PI-LL values, suggesting possible misalignment. The ANOVA revealed no significant difference (F-statistic: 0.53, p-value: 0.595) in T1 slope outcomes across the PI groups, suggesting that the strategies applied do not lead to significantly varied results in this parameter. Concordance analysis demonstrated a moderate positive correlation (τ = 0.374, p = 0.011) between PI and T1PA, emphasizing the role of PI in achieving better T1PA alignment. Cluster analysis further categorized the strategies into three groups, with Cluster 0 showing balanced outcomes, while Clusters 1 and 2 exhibited deviations that may lead to adverse effects. Principal component analysis highlighted that cervical alignment measures, particularly T1-CL and C2 Slope, were the primary drivers in differentiating the strategies. Conclusion: This study underscores the importance of optimizing PI over C2 plumbline adjustments in achieving favorable spinal alignment, particularly with respect to T1PA. While some strategies provide better stabilization, others frequently lead to misalignment. The findings suggest that clinical interventions should prioritize PI adjustments, especially in high PI cases, to achieve optimal spinal correction. Additionally, strategies leading to lower PI-LL values should be approached with caution. The results highlight the need for personalized treatment strategies based on individual PI characteristics to achieve balanced and stable spinal alignment outcomes. Devender Singh 1 , Matthew Geck 1 , Vik Kohli 1 , John Stokes 1 , Eeric Truumees 1 1 Ascension, Austin, United States Introduction: Spinal alignment is crucial for maintaining biomechanical integrity and functional stability, with parameters such as T1 Slope (T1 SPI) and T1 Pelvic Angle (TPA) serving as critical indicators of spinal health. The relationship between these parameters and varying spinal curvatures defined by Pelvic Incidence (PI) provides key insights into the biomechanical responses associated with spinal deformities and clinical conditions. This study aims to elucidate the behavior of T1 Slope and TPA across different degrees of spinal curvature, categorized by low, moderate, and high PI, to determine whether T1 Slope remains stable and whether TPA exhibits significant disruption with increasing spinal curvature. Our Null hypothesis was that T1 Slope remains relatively stable across different levels of spinal curvature categorized by pelvic incidence (PI), while T1 Pelvic Angle (TPA) progressively increases and becomes significantly disrupted with higher degrees of spinal curvature. Materials and Methods: A dataset comprising 75 radiographic measurements was analyzed, collected from biomechanical models encompassing various spinal curvature profiles. Spinal curvature was categorized based on PI values into three groups: low (PI ≤ 45), moderate (45 < PI < 75), and high (PI ≥ 75). Statistical analysis was performed using one-way ANOVA to assess the significance of differences in T1 Slope and TPA across these categories, supplemented by correlation analysis to examine the associations between PI, T1 Slope, and TPA. Boxplot visualizations were employed to delineate trends and distributions within the curvature categories. Results: The results indicated that T1 Slope remained relatively consistent across different PI categories, with mean values of -2.38 (low), -4.94 (moderate), and -5.14 (high). The ANOVA p-value of 0.301 indicated that these differences were not statistically significant, affirming the hypothesis that T1 Slope remains minimally affected by changes in spinal curvature. Conversely, TPA exhibited a progressive increase with rising curvature severity, with mean values of 9.55 (low), 13.10 (moderate), and 15.59 (high). The ANOVA p-value of 0.044 demonstrated statistical significance, supporting the hypothesis that TPA becomes increasingly disrupted as spinal curvature intensifies. Conclusion: The findings substantiate the stability of T1 Slope across varying levels of spinal curvature, underscoring its reliability in clinical evaluation frameworks. In contrast, the significant disruption observed in TPA with increasing curvature severity highlights its sensitivity to changes in spinal alignment. The moderate positive correlation between PI and TPA suggests that while PI exerts a discernible influence, other biomechanical factors may also contribute to TPA variability. Future investigations should focus on identifying additional determinants and refining curvature classification criteria to enhance the precision and applicability of these findings in clinical contexts. Oleksii Nekhlopochyn 1 , Vadim Verbov 2 , Ievgen Cheshuk 2 , Michael Karpinsky 3 , Oleksandr Yaresko 3 1 Romodanov Neurosurgery Institute, Spine Neurosurgery, Kyiv, Ukraine , 2 Romodanov Neurosurgery Institute, Restorative Neurosurgery Department, Kyiv, Ukraine , 3 Sytenko Institute of Spine and Joint Pathology, Laboratory of Biomecanics, Kharkiv, Ukraine Introduction: In the structure of all traumatic spine injuries, the thoracolumbar junction is predominant, accounting for over 53% of all vertebral fractures. One of the most clinically significant types of injuries in this area is burst fractures. The aim of our study is to analyze the stress-strain state of the model of the thoracolumbar spine with a burst fracture of the Th12 vertebra under various transpedicular fixation options influenced by compressive loading. Materials and Methods: The study developed and investigated a finite element model of the thoracolumbar spine with a burst fracture of the Th12 vertebra. The burst fracture was modeled by dividing the vertebral body of Th12 into several planes, transforming it into separate fragments. The gaps between these fragments were filled with a material that simulated the interfragmentary regenerate. Variants of transpedicular stabilization using different types of screws, mono- or bicortical, and with or without cross-links, were examined. The model was analyzed under compressive loading. Results: The maximum level of stress among the bone structures directly involved in fixation was registered in the L2 vertebral body. It amounted to 19.9, 15.6, 19.4, and 15.1 MPa, respectively, for models with monocortical screws without cross-links, with bicortical screws without cross-links, with monocortical screws with cross-links, and with bicortical screws with cross-links. Simultaneously, the screw entry zone into the arch of this vertebra shows values of 10.1 MPa, 15 MPa, 10.2 MPa, and 14.3 MPa for these models respectively. Peak loads on the metal structure elements are observed on the rods, amounting to 212.5 MPa, 159.6 MPa, 203.7 MPa, 142.8 MPa respectively for the considered models. When analyzing the load distribution directly on the transpedicular screws, which are the second most common site of implant failure, it was observed that the screws implanted in the vertebral bodies of Th10 and L2, located distally from the fracture site, bear the highest loads. The recorded stress values for the models were 21.4, 23.5, 20.6, and 22.6 MPa for the Th10 screws, and 35.8, 41.4, 33.2, and 39.6 MPa for the L2 screws. Conclusion: The results of the study showed that under the influence of compressive loading when modeling a burst fracture of the thoracolumbar junction, the use of long screws leads to a reduction in stress levels, both in the elements of the metal structure and in the bone elements of the model, while the use of transverse connectors has a negligible effect. Javier Castro 1 , James Mok 1 , Karl Bruckman 1 , Calvin Chan 1 , Anna Karnowska 1 , Harsh Wadhwa 1 , Olivia Okoli 1 , Jayme Koltsov 1 , Serena Hu 1 1 Stanford University, Stanford, United States Introduction: Dental composites are commonly used for fixing orthodontic brackets to teeth. We hypothesize that it could be used as an alternative fixation method to bone for applications such as spinal instrumentation. With properties such as flexibility, bioactivity, and adhesive strength, composites present a promising option for applications necessitating robust adhesion to bone. This porcine study investigates the impact of composite area on vertebral bonding strength. Material and Methods: 20 vertebrae from a fresh frozen porcine specimen were meticulously harvested and cleaned of all soft tissues for testing purposes. The vertebrae were then randomly divided into four groups with various number of brackets and composite (Filtek™ Bulk Fill Posterior Restorative, OptiBond Solo Plus) footprint: 1) single bracket with 5mm composite footprint, 2) single bracket with 10mm footprint, 3) double brackets with 5 mm footprint, and 4) double brackets with 10mm footprint. The lamina was treated with etching acid solution and dental bonding agent before an orthodontic metal bracket was attached. Each specimen was attached to an Instron universal testing machine ( E10000 ) to assess the axial ultimate load (pull-out) of each construct. A t-test analysis compared the ultimate load among the four groups. Results: A single bracket with a 5mm footprint exhibited an ultimate load of 95.9 ± 28.7N, which was significantly lower than the single bracket with a 10 mm footprint, 147.7 ± 29.7N (p < 0.001), double bracket with a 5 mm footprint each, 133.4 ± 38.1N (p < 0.05), and double bracket with a 10 mm footprint area, 161.8 ± 69.4N (p < 0.05). There was no significant difference between the remaining three groups (p = 0.5). Conclusion: Greater composite surface area was associated with greater axial load strength, while number of brackets did not affect it. Orthodontic brackets can effectively be implanted on porcine vertebra to assess fixation stability. Dental composite can be used as a type of vertebral fixation in a porcine model. Composite surface area correlates with fixation strength. Fabian Kress 1 , Konrad Schütze 1 , Florian Gebhard 1 1 University of Ulm, Ulm, Germany Introduction: Osteoporotic pelvic ring fractures are increasingly common due to demographic shifts. This study evaluates the biomechanical stability of different fixation techniques for fragility fractures of the pelvis (FFP) type IIc, focusing on combined anterior and posterior pelvic ring fracture treatment. Material and Methods: Twelve fresh frozen female cadaveric pelvises (mean age 86.9 ± 10.5 years) were used. FFP type IIc fractures were simulated and stabilized posteriorly with a transsacral-transiliac screw. Anterior fixation methods included: (1) no fixation (control), (2) external fixator, (3) 4.5 mm retrograde screw, and (4) 7.3 mm antegrade screw. Biomechanical testing simulated one-leg stance conditions with cyclic loading until failure. Fracture displacement and stability were analyzed using optical cameras. Statistical analysis used the Mann-Whitney U test with a significance level of 0.05. Results: Initial construct stiffness showed no significant differences between groups (p = 0.997). Both screw fixation techniques demonstrated superior performance in cycles to failure, with significant differences observed for the 5mm ramus displacement criterion (p = 0.005). The retrograde screw group showed the highest number of cycles to failure (10,819 ± 3,227), followed by the antegrade screw group (9,714 ± 5,485). Total displacement at the ramus fracture point differed significantly between groups (p < 0.001), with screw fixations showing significantly less displacement compared to the control group. Posterior dislocation was lower for external fixator and screw groups compared to the control, without statistical significance. Conclusion: Antegrade and retrograde screw fixation techniques provided enhanced stability and longevity compared to external fixation or no fixation for FFP type IIc fractures. These findings may have important implications for the surgical management of osteoporotic pelvic ring fractures, potentially leading to improved patient outcomes and reduced complications. Mauro Bruzzone 1 , Abel Benedetto 2 , Andrey Martinez Pardo 1 , Pablo Rizzi 1 1 Hospital Español de Buenos Aires, Orthopaedics, Buenos Aires, Argentina , 2 HZGA General Manuel Belgrano, Orthopaedics, Spine Surgery, San Andrés, Provincia de Buenos Aires, Argentina Introduction: The loss of lumbar lordosis can cause sagittal imbalance, which can result in “ flat-back syndrome ”. Our aim was to define if the position of rectangular interbody cages can cause changes in the lordosis of the segment where they are placed. Likewise, we attempted to correlate changes in the lordosis of the L4-L5 and L5-S1 segments, as well as global postoperative lordosis, with the position of the cage in the sagittal plane. Material and Methods: Retrospective analysis of x-rays of 35 patients with posterior lumbar fusion using cages without angulation, surgically treated between 2018 and 2019. 10 cases (28.6%) were L5-S1 fusions, and 25 (71.4%) are L4-S1 fusions. 20 patients (57.1%) were men and 16 (45.7%) were women. The entire series were operated by the same team, using cages with 0° of lordosis. All the cases had a preoperative radiograph and a postoperative radiograph in the postoperative month, and another one between 1 and 2 years postoperative. None of these cases were patients with L4-L5 arthrodesis only or presented any sign of loosening or infection during the postop. A statistical analysis was performed using t -test for paired samples to assess differences between pre- and postoperative L4-L5 and L5-S1 lordosis. The correlation between preoperative lordosis and the global lumbar lordosis (GLL) posterior gap ratio (PGR) and center point ratio of each segment (CPR) for L4-L5 and L5-S1 was assessed using Pearson correlation. The correlation between postoperative global lordosis and segmental lordosis of each segment caudal to L1-L2 was analyzed using the same test. The α level was set at 0.05 for statistical significance. Results: Changes in lordosis both in the early and late postoperative period, with respect to preoperative lordosis, did not show significant differences (early postop {EP}: p = 0.893, late postop {LP} p = 0.957). The correlation between the postoperative lordosis and the early postoperative segmental lordosis of the L2-L3 and L3-L4 segments was significant, with the addition of L1-L2 in the late postoperative period (EP: p = 0.03 for L2-L3; p = 0.02 for L3-L4, LP p = 0.001 for L2-L3; p = 0.001 for L3-L4, p = 0.006 for L1-L2). The changes in L4-L5 segmental lordosis in the preoperative compared to the postoperative period were not significant. They were significant in L5-S1, where lordosis was even decreased (L4-L5 EP: p = 0.529, LP: p = 0.923; L5-S1 EP: p = 0.023, LP: p = 0.026). We found no correlation between cage position in terms of cage centroid ratio (CPR) and posterior space ratio (PGR), with respect to postoperative segmental lordosis or postoperative global lordosis (L4-L5 EP: p = 0.39, LP: p = 0.913; L5-S1 EP: p = 0.85, LP: p = 0.68; GLL EP: p = 0.913; LP: p = 0.68). Conclusions: In the present study we found that the variations in L4-L5 segmental lordosis comparing pre and postoperative were not significant. The difference between pre and postoperative segment L5-S1 (loss of lordosis) was significant. The global lumbar lordosis did not change. Segmental lordosis with the use of rectangular cages does not improve segmental or global lordosis, regardless of its anterior placement. Jan Wulf 1 , Nele Baur 1 , Kistler Manuel 1 , Titus Kuehlein 1 , Kenny Hagar 1 , Hannes Traxler 2 , Carl Neuerburg 1 , Böcker Wolfgang 1 , Holzapfel Boris 1 , Adrian Cavalcanti Kußmaul 1 1 Musculoskeletal University Center Munich, Trauma and Orthopedic Surgery, Munich, Germany , 2 Medical University of Vienna, Center of Anatomy and Cell Biology, Division of Anatomy, Vienna, Austria Introduction: In the revision of S2AI (S2 alar-iliac) screws, choosing the correct screw diameter is not just a technical necessity but is crucial for ensuring surgical success. This biomechanical study aims to address an important question: Does increasing the screw diameter to 11.5 mm provide a significant stability advantage over using a 10.5 mm screw in revision surgeries? Materials and Methods: To investigate this, we implanted S2AI screws with a diameter of 9.5mm bilaterally into 13 human cadaveric pelvises, separated along the parasagittal plane at the level of the S1 neuroforamen. Each screw was subjected to cyclic vertical loading via a connecting rod until a loosening of more than 5mm occurred. Following this, a revision surgery was performed bilaterally using either a 10.5 mm or 11.5 mm screw on each side of one pelvis. The same rigorous loading procedure was then repeated to assess the difference in the load required to induce the same level of loosening. The outcomes were analyzed in a matched-pair analysis using a two-tailed paired t-test. After excluding 5 specimens with reduced stability after revision surgery, absolute and relative increases in stability were further analyzed using a two-tailed Wilcoxon matched-pairs signed rank test. Results: Revision with the 10.5mm screw significantly improved stability compared to the original 9.5 mm screw, with a mean increase from 306.2N to 348.1N until loosening occurred (p = 0.021). The 11.5 mm screw also showed a significant improvement compared to the 9.5 mm screw, with a mean increase from 265.5N to 319.3N (p = 0.024). However, when comparing the two revision screws directly, the expected additional benefit of the larger 11.5 mm screw was not observed. There was no significant difference in the median absolute increase in load capacity between the 10.5 mm and 11.5 mm screws (+46.5N vs. +56N; p > 0.999). Additionally, the relative increase in load, measured as fold change compared to the initial 9.5mm screw, was similar between the two groups (1.19 vs. 1.21; p = 0.844). Conclusion: Both 10.5 mm and 11.5 mm revision screws provide a significant increase in stability compared to the original 9.5mm screws. However, the 11.5 mm screw does not offer a significant additional stability benefit over the 10.5mm screw. This suggests that, in revision surgeries, opting for a 1mm larger diameter screw is likely sufficient. Additionally, other factors seem to influence overall stability, as observed with reduced load until failure in 5 cases. Future research should explore additional factors beyond screw diameter that may affect the stability of revision screws. Junyu Li 1 , Lizhi Xu 1 , Haotian Wang 1 , Yinhao Liu 1 , Zhuo Ran Sun 1 , Yongqiang Wang 1 , Miao Yu 1 , Weishi Li 1 , Yan Zeng 1 1 Peking University Third Hospital of China, Beijing, China Introduction: In the background of the aging population, osteoporotic vertebral compression fracture (OVCF) is one of the main complications of osteoporosis. Patients with severe OVCF usually suffer from local kyphosis or even sagittal imbalance, which seriously affecting the patients’ quality of life and causing nerve damage and back pain. For OVCF patients with severe spinal kyphosis, osteotomies may be necessary to correct sagittal alignment, and it is effective for relieving neurological impairments due to spinal cord compression. Several osteotomy methods have been introduced into clinical practice. Considering advanced age and severe osteoporosis in OVCF patients, there is high perioperative risk and high incidence of postoperative mechanical complications which leaves a clinical challenge to choose the optimal osteotomy method for orthopedic surgeons. Thus we conduct this study, in which we compared the clinical outcomes of different osteotomy methods for OVCF and applied finite element analysis to evaluate the biomechanical features of a spine after several osteotomies, in order to verify the most ideal osteotomy method for OVCF kyphosis. Material and Methods: A total of 33 continuous patients with no significant difference in risk factors related to the complications was enrolled in this retrospective study. Sagittal parameters were measured in the pre-, post-operative and following-up orthostatic flat films. An finite element (FE) model was created using CT scanning from a female volunteer with OVCF but no other severe spinal deformities. PSO, VCR and mPSO for OVCF were simulated on FE model. Stress distribution characteristics, load sharing, strain displacement and strain angle change were measured. Results: Clinical - All differences in preoperative spinal sagittal parameters were not statistically significant. Compared to PSO, mPSO showed a significant delince in postoperative LL, TKmax, SVA and TPA, as well as in last followingup TPA. The difference in post-operative SVA and TPA values between mPSO and VCR is statistically significant. The operation duration and intraoperative blood loss of mPSO are less than the other two. For postoperative complications, no statistically significant differences were observed. Biomachanical - Six operating conditions (flexion, extension, left/right bending, left/right twisting) for each post-operative FE model have been examined. In most actions, the displacement of mPSO is similar to that of PSO, with both larger than that of VCR. All the maximum equivalent stress on the vertebral body is within the safe range. The stress is mainly distributed on the T10 vertebral body and the fixed vertebral body L2, while the stress of VCR is greater than that of mPSO and PSO. The intervertebral disc pressure is highest in VCR, followed by PSO, and lowest in mPSO under all conditions. The maximum pressure on the intervertebral discs is located between T10 and T11. Conclusion: The finite element analysis showed that mPSO has a similar spine stability to PSO, and possibly creates a better environment for bone-to-bone fusion and prevents adjacent segments degeneration. Combined with its smaller surgical risks, we believe that the modified pedicle subtraction osteotomy may be an appropriate surgical intervention for indicated cases of OVCF. Charles Taylor 1 , James Geddes 1 , Hasan Raza 1 , Liam Rose 1 , Jean Charles Le Huec 2 , Tim Bishop 1 , Jason Bernard 1 , Darren Lui 1 1 St George's Hospital, London, United Kingdom , 2 Bordeaux University Hospital, Bordeaux, France Introduction: Traditionally we consider the Pelvic Incidence to be a static parameter once we achieve skeletal maturity. A harmonious spinal ratio is when Pelvic Incidence (PI) is approximately equal to the lumbar lordosis (LL). Altering the lumbar lordosis to match the pelvic incidence is now an established best practice. However, surgically altering Pelvic Incidence (PI) may prove an effective operative stratagem following pathological spinopelvic parameter changes altering the PI- LL ratio. An H-type fracture through the sacrum may cause sacral slope angular change and Pelvic Incidence change. Therefore, an elective H type Sacral osteotomy is one such proposed method. This study uses a saw-bone and cadaveric with a single patient report to demonstrate the feasibility, safety and effectiveness of sacral osteotomy to alter PI. Material and Methods: Proof of concept was first tested with a saw bone spinal-pelvic model. An H type fracture lateral to the sacral foramina was cut. Trans-sacro-iliac screws were then inserted. Rotation with high and low sacral slope were radiographed. Secondly, a cadaveric model was tested in a similar method. Sagittal plane osteotomies were made lateral to the neuroforamina. A trans-iliac screw was passed through S1 and the osteotomy was mobilized, the sacrum rotated around the pivot to change the Pelvic Incidence. Rotational correction was locked with S1 to Iliac pedicle screw constructs and rods. Radiographic analysis was conducted. This same surgical concept was then applied to a patient who sustained complex H type S2 fractures. The H type fracture pattern emulated the elective cadaveric osteotomy. Instrumentation was inserted to change the PI. Results: In the saw-bone model the osteotomy allowed for unrestricted correction of PI in an arc from 0 - 90°. The pelvic locking screws enabled pivotal function and provided primary stability. In the cadaveric study pelvic floor attachments result in a rotational restriction to 15°. The patient case-report showed good correction of pelvic and sacral alignment with adequate post-operative outcomes. A minimum distance from osteotomy to sacral neuroforamina of at least 3mm and a safety margin towards the iliac vessels and the rectum of at least 15mm on axial CT imaging is recommended. Conclusion: Rotational sacral osteotomy appears to be feasible and safe method for modifying PI in patients with pathological changes in spinopelvic parameters. We suggest that this allows control of the Sacral Slope and some alteration of the Pelvic Incidence. Further clinical studies are required. Haolin Sun 1 , Shijun Wang 1 , Yuetian Wang 1 1 Department of Orthopedics, Peking University First Hospital, Beijing, China Introduction: Conventional pedicle screw (CPS) fixation in osteoporotic spines is challenging. Cortical bone trajectory (CBT) screws can enhance screw holding power by more cortical bone contact. However, the standard CBT (S-CBT) screws would face a series of problems such as stress concentration and poor fatigue resistance. The S-CBT screw technique was modified to accommodate longer screws, and the biomechanical behaviors of this modified CBT (M-CBT) screw technique were investigated. Material and Methods: This is a finite element analysis and biomechanical cadaveric study. A validated nonlinearly L1-S1 finite element model was employed in this study. Three L4-5 fusion models, namely CPS, M-CBT, and S-CBT, were generated using interbody fusion cages and different screw fixations. Next, the models were loaded to simulate flexion, extension, lateral bending, and rotation motion. The range of motion (ROM) and peak Von Mises stress of the Cage, rods, screws, and intervertebral discs were analyzed. Besides, three types of cadaveric lumbar fusion modes were constructed by various screw trajectories. The models underwent 10000 cycles of loading to record the displacement of the vertebral body. Afterward, the individual screws were subjected to axial pull-out tests, and the maximum pulling-out force was documented. Finally, the data were compared across the three different fusion models. Results: Regarding six degrees of freedom movements, the three types of fixation models significantly increased ROM of the adjacent segments (L3-4 and L5-S1) (p = 0.002), but the difference in ROM increment among the three types of models was not significant (p = 0.097). Compared with the S-CBT model, the peak Von Mises stress of the Cage in the M-CBT model was lower by 7.92%, 24.78%, 19.22%, and 56.05% during flexion, extension, right bending, and left rotation directions, respectively. Compared with S-CBT, the peak Von Mises stress of L5 screws in the M-CBT model was lower by 18.14%, 26.85%, 1.18%, 23.65%, 13.91%, and 2.68% during flexion, extension, left bending, right bending, left rotation, and right rotation, respectively. In the biomechanical test, the fatigue displacement results revealed that the displacement of M-CBT was between S-CBT and CPS under both maximum and minimum forces, with statistically significant differences (p < 0.05). Additionally, the results of the anti-pull-out test following fatigue loads demonstrated that the M-CBT group had the largest Fmax [381.80 (119.00, 852.20)], followed by the CPS group [329.10 (117.00, 507.80)] and the S-CBT group [321.50 (196.60, 887.20)], but the differences were not statistically significant (p = 0.665) in the upper vertebral subgroup. Conversely, the Fmax of M-CBT [384.20 (314.00, 851.20)] was significantly higher than that of S-CBT [264.70 (118.80, 477.40)] and CPS [282.20 (50.80, 595.20)] in the lower vertebral subgroup, and the difference between M-CBT and S-CBT was significant (p = 0.037). Conclusion: M-CBT could enhance the control force of the anterior column of the vertebral body by increasing the inserted screw length, minimizing the stress on the cages and screws, and optimizing the anti-fatigue performance of the internal fixation system compared to S-CBT. Zhaohai Pang 1,2 , Qiang Yang 2 1 Tianjin Medical University, Tianjin, China , 2 Tianjin University Tianjin Hospital, Tianjin, China Introduction: Oblique Lateral Interbody Fusion (OLIF) is an important surgical method for treating degenerative lumbar diseases. Various internal fixations can be used in conjunction with OLIF to enhance its stability and reduce complications. However, it is currently unclear whether osteoporosis affects the success of internal fixation; therefore, this study analyzes the impact of osteoporosis on OLIF combined with different internal fixations. Material and Methods: We developed and validated a three-dimensional nonlinear L3-S1 finite element (FE) model of the spine. We assigned different material properties to each part of the model to establish models of osteoporotic and normal lumbar spines. We analyzed OLIF combined with the following five internal fixation methods: OLIF Stand-alone; OLIF with lateral plate fixation (OLIF+LPF); OLIF with trans facet joint screw fixation and unilateral pedicle screw fixation (OLIF+TFJF+UPSF); OLIF with unilateral pedicle screw fixation (OLIF+UPSF); OLIF with bilateral pedicle screw fixation (OLIF+BPSF). Under different computational conditions, we calculated the range of motion (ROMs) for normal bone mass and osteoporotic models, the maximum von Mises stress of the fixation instruments (MMSFIs), and the average von Mises stress of the cancellous bone (AMSCBs). Results: Compared to the normal bone mass OLIF model, there was no significant change in any segmental ROM in the osteoporotic OLIF model. The MMSFIs increased in all five types of osteoporotic OLIF models. In the OLIF+TFJF+UPSF model, the MMSFIs increased dramatically under flexion and extension conditions. The stress changes in the OLIF+UPSF, OLIF+BPSF, and OLIF+TFJF+UPSF models were similar; all stresses showed an upward trend. In all five types of osteoporotic OLIF models, the AMSCBs decreased during extension, flexion, lateral bending, and axial rotation. The average stress of the cancellous bone was most pronounced during extension. The AMSCBs in each group of OLIF models decreased by 14%, 23.44%, 21.97%, 40.56%, and 22.44%, respectively. Conclusion: Compared to the normal bone mass OLIF model, the AMSCBs in the osteoporotic OLIF model were reduced, and the MMSFIs were increased. Therefore, the biomechanical performance of the osteoporotic model may not be as good as that of the normal model for the same fixation method; in some cases, it may increase the risk of fracture and failure of internal fixation. Gregory Malham 1 , Wenhai Wang 2 , Josh McGuckin 2 , Jonathan Mahoney 2 , Dean Biddau 1 , Brandon Bucklen 2 1 Epworth HealthCare, Melbourne, Australia , 2 Globus Medical, Philadelphia, United States Lateral lumbar interbody fusion (LLIF) is a minimally invasive surgical technique that provides a wide footprint interbody spacer for correction of lumbar coronal and sagittal deformity. Traditional spinal interbody fusion procedures utilize pedicle screws and rods for additional stability. An expandable lateral titanium interbody spacer with an integrated lateral fixation (eLLIFp) device provides a stand-alone LLIF that is intended to function autonomously. This may reduce the complexity of the surgery and the potential risks associated with supplemental posterior instrumentation. The minimum acceptable screw length to promote adequate biomechanical fixation and stability for a stand-alone eLLIFp has not been determined. To investigate the effective ratio (of screw length/spacer length) of a stand-alone eLLIFp construct that provides adequate biomechanical fixation and stability as compared to the eLLIFp with supplemental bilateral pedicle screw-rod fixation. Specimens were selected based on similar age and DEXA scores. ROM of intact specimens was measured before treatment with LLIF at L3-4. Specimens were treated with expandable lateral interbody spacers with integrated fixation (eLLIFp stand-alone) or eLLIFp with supplemental posterior fixation using bilateral pedicle screws and rods (eLLIFp + BPS). ROM was measured using a custom-built motion simulator (± 7.5 Nm) capture system and normalized as a percentage of intact. Four patient-specific lumbar functional spinal units using finite element models were developed, validated, and then instrumented with eLLIFp stand-alone devices. The integrated screw lengths were varied to achieve screw-to-spacer length ratios of 0.6, 0.75 and 0.9. Stresses were compared among the constructs under a 7.5 Nm pure moment load in FE, LB, and AR. The eLLIFp stand-alone constructs were not sensitive to the screw-to-spacer length ratio during FE and LB (with only an 8% change in motion relative to intact). However, AR had a linear 24% reduction in motion as the ratio increased. Regression analysis revealed that the median performance of eLLIFp stand-alone with a ratio of 0.9 in AR had equivalent performance to eLLIFp + BPS constructs with a ratio of 0.75. AR imposed the highest stresses on the eLLIFp and these stresses increased with higher ratios (maximum stress 268.5 MPa for ratio 0.9 during AR), yet implant failure was improbable due to the material properties of the titanium alloy used. Similarly, surrounding bone stresses were higher during AR and longer screws reduced these stresses (64.6 MPa for a 0.6 ratio, as compared to 45.7 MPa with a 0.9 ratio). For stand-alone eLLIFp, each 5 mm increase in screw length with a constant spacer length decreased torsional ROM by 8%. However, an absolute threshold ratio for optimal clinical outcome performance of eLLIFp cannot be prescribed. Stand-alone eLLIFp with a 0.9 ratio demonstrated comparable ROM to eLLIFp + BPS constructs with a 0.75 ratio. Implant stress findings reinforced torsion as the critical loading condition. Surrounding bone stress decreased as the screw length increased, indicating the benefit of using longer screws. Surgeons using eLLIFp should consider longer screw lengths aiming for an ideal screw-spacer ratio of 0.9 based on anatomical considerations. Giulia Cavazzoni 1 , Margherita Pasini 1 , Luca Cristofolini 1 , Enrico Dall'Ara 2,3 , Marco Palanca 1 1 University of Bologna, Dept. of Industrial Engineering, Bologna, Italy , 2 University of Sheffield, Division of Clinical Medicine, Sheffield, United Kingdom , 3 University of Sheffield, Insigneo Institute, Sheffield, United Kingdom Introduction: Vertebral metastases compromise the correct functionality of the spine, introducing pain, spinal instability and highly impacting patients’ quality of life. Understating the actual risk of fracture in those patients is mandatory. Among the biomechanical parameters used to stratify patients and assess the risk of fracture in metastatic vertebrae [1], poor importance is offered to the intervertebral disc (IVD) conditions. This study aimed to evaluate if and to what extent the IVD degeneration affects the mechanical behaviour of metastatic vertebrae. Material and Methods: Ethical approvals were obtained from the University of Bologna and University of Sheffield. Eight spine segments consisting of a healthy (control) vertebra and a vertebra with lytic metastases were prepared. The specimens were loaded in axial compression in physiological conditions (without inducing damage to the vertebrae and IVDs). Then, a severe disc degeneration was simulated injecting a cocktail of collagenase type II (Gibco TM , 125 U/mg) and phosphate-buffer solution (concentration 2mg/ml) in the nucleus pulposus. Finally, the specimens were tested in the same physiological loading conditions applied before degeneration, and up to failure. 5/8 specimens were tested in a custom jig placed within a microCT scanner (VivaCT80, Scanco) in order to measure the deformation inside the vertebral bodies with a Digital Volume Correlation approach [2]. 3/8 specimens (did not fit the microCT scanner) were tested in a multi-axial testing machine and a Digital Image Correlation system was used to measure the deformation on the cortical shell [3]. Compressive deformations measured in the control and metastatic vertebrae were compared before and after the degeneration using a Wilcoxon test. Failure location was identified looking at the deformation maps and overlapping the microCT scans acquired in unloaded condition and after failure. Results: The metastatic vertebrae experienced -1395 microstrain and -5002 microstrain within the vertebral bodies, before and after IVD degeneration; and -1212 microstrain and -1490 microstrain on the cortical shell, before and after IVD degeneration. The control vertebrae experienced -1365microstrain and -3857microstrain within the vertebral bodies before and after IVD degeneration; and -1203 microstrain and -1306 microstrain on the cortical shell, before and after IVD degeneration. Wilcoxon test revealed that compressive deformations measured within the vertebral bodies were different before and after degeneration (p < 0.05). No differences were observed in the cortical shell. Failure occurred in the mid-height of the metastatic and/or control vertebral body involving both the trabecular bone and the cortical shell, leading to a shift of the endplate without damaging it. Conclusion: Degeneration of the IVDs changes the deformation experienced by the vertebrae, increasing the risk of fracture. In addition, the failure location results different with respect to vertebrae loaded by healthy IVD [3]. In conclusion, these results suggest the clinical relevance of including IVDs level of degeneration evaluation to assess patients’ risk of spinal instability. References [1] Fisher et al., Spine 2010; [2] Palanca et al., Bone 2023, [3] Palanca et al., Bone 2021 Acknowledgement The study was funded by the AOSpine Knowledge Forum Associate Research Award ( AOS-KF-TUM-22-003 ). Sean Murray 1 , Mark Driscoll 2 1 McGill University, Biological and Biomedical Engineering, Montreal, Canada , 2 McGill University, Mechanical Engineering, Montreal, Canada Introduction: Low back pain (LBP) is the leading cause of disability globally, affecting as many as 84% of people. The cause remains unidentified for most, raising direct costs for treatment of back conditions to over $315B per year in the USA. Lifting velocity is a high-risk factor for LBP in occupational settings and intra-abdominal pressure (IAP), the pressure concealed within the abdominal cavity, is known to fluctuate transiently during lifting. The role of IAP in transient lifting remains largely unaddressed in biomechanical models, despite its known contribution to spine stability and apparent relevance in the multifactorial pathomechanism of LBP. The objective was to evaluate the contribution of IAP toward spinal stability at different loading rates and, further, to provide insight into how lifting velocity can affect low back injury mechanics. Material and Methods: A non-linear, transient finite element (FE) model of the lumbar spine and surrounding anatomy was developed and validated as a modified and expanded iteration of a prior spine model. An anatomically accurate abdominal compartment was created, enclosed by soft and bone tissue relevant in loading the spine via IAP. The model and discretization were validated in comparison with available data types according to industry standards. Flexion moments, combined with 1175 N follower load, were first tuned to target in vivo intervertebral rotation (IVR) patterns at 20° net L1-S1 rotation. Six load cases were then simulated transiently, driving extension back to standing posture at 80°/s, 40°/s, and 10°/s velocities, with direct IAP control 0 mmHg and 75 mmHg IAP. Intrinsic stiffness was evaluated from angular deviation from the baseline trajectory after application of a 5 Nm perturbation torque at T9 and L1. Results: The spine FE model was well aligned with published ex vivo and in vivo data for IVRs and intervertebral disc pressure. Mesh convergence showed the lumbar spine was not sensitive to further mesh refinement, with IVRs growing by 1.7% at most. Statically, high IAP introduced a 19.9 Nm extension moment. Transiently, at all flexion-ascension velocities, high IAP reduced the angular response to perturbation. The effect was greatest at fast movement with a 0.948 Nm/° or a 33% gain in stiffness, compared to 30% and 24% at slow and medium velocities. Without IAP, stiffness increased proportionally to velocity when calculated relative to the starting angle, but the differences were mostly negated by the offsetting effect of faster baseline trajectories. Intrinsic stiffness was slightly higher at 40°/s, with 3.1 Nm/°. Conclusion: These findings indicate an airbag-like role of IAP during lifting as it heightens lumbar spine stability by increasing intrinsic stiffness. Since faster lifting is induced by larger loads, the passive displacement-limiting gain of IAP holds greater weight with increasing velocity. The results further support the importance of IAP as a factor in the pathomechanism of LBP, highlighting the potential for stability gain without the cost of additional loading on the spine. Ineffective abdominal muscle activation to generate IAP or poor timing during a lift can increase low back injury risk due to insufficient lumbar spine stability. Saif Toumi 1 , Majdi Ben Romdhane 2 , Alaa Lessoued 3 1 Ben Arous Orthopedic and Trauma Center, Tunis, Tunisia , 2 La Marsa Interior Forces Hospital, Tunis, Tunisia , 3 Ben Arous Orthopedic and Trauma Center, Tunisia Introduction: The Roussouly classification provides a framework for categorizing lumbar lordosis patterns based on radiographic measurements, potentially influencing the development of lumbar pain. This study aims to evaluate the incidence of lumbar pain (lombalgia) among patients classified according to the Roussouly classification. Material and Methods: A retrospective analysis was conducted involving 100 patients who underwent lumbar spine radiography and were subsequently classified using the Roussouly system. Patient data, including demographic details, clinical history, and incidence of lombalgia, were collected and analyzed. The correlation between Roussouly classification types and reported lumbar pain was assessed. Results: Of the 100 patients, 70% were classified as Roussouly type I, 15% as type II, 10% as type III, and 5% as type IV. Lombalgia was reported in 45% of patients. The incidence of lombalgia varied by Roussouly type: 40% in type I, 53% in type II, 60% in type III, and 80% in type IV. A significant association was found between Roussouly types and the prevalence of lombalgia (p < 0.05). Conclusion: The Roussouly classification correlates with the incidence of lombalgia, with higher prevalence observed in patients with more pronounced sagittal imbalance as classified by the Roussouly system. This suggests that sagittal spinal alignment may be a factor in the development of lumbar pain. Further research is warranted to explore the underlying mechanisms and to refine treatment strategies based on Roussouly classification. Emiliano Vialle 1 , Otávio Vitório Alvarenga Pereira 1 , Vinícius Lopes Fruet 1 , Paulo Meira 1 , Luan Araujo 1 1 Pontifícia Universidade Católica do Paraná, Hospital Universitário Cajuru, Orthopedics and Traumatology Service, Spine Surgery group., Curitiba - PR, Brazil Introduction: Degenerative lumbar diseases are one of the most common causes of disability, affecting around 266 million people annually. With the degeneration of the spine, it is common for changes in spinopelvic parameters to occur in patients. Currently, it is known that to maintain proper sagittal alignment after surgery and reduce energy expenditure during walking, it is necessary to adjust lumbar lordosis according to pelvic incidence. Our goal is to evaluate the difference between standing and supine lumbar lordosis (lordosis delta) as a predictor of lumbar spine stiffness in patients undergoing surgical treatment for degenerative lumbar diseases. Materials and Methods: Patients with degenerative lumbar diseases undergoing surgical treatment at Cajuru University Hospital were included in the study. Inclusion criteria: patients aged 18 years or older, diagnosed with degenerative lumbar disease (spinal canal stenosis with or without degenerative spondylolisthesis), pre- and postoperative standing X-rays, preoperative lumbar MRI, and lumbar decompression with or without posterior fixation and additional interbody fusion. Spinopelvic parameters and lumbar lordosis were assessed on X-rays and MRI. Lumbar lordosis (LL), segmental lordosis, and pelvic incidence (PI) measurements were recorded on preoperative X-rays, preoperative MRI, and postoperative X-rays. Sagittal balance was calculated using the PI-LL formula (a value ≤10 indicates balance). The Roussouly classification was used to categorize lumbar lordosis. Results: Forty-nine patients (25 women and 24 men) were included. Operated levels: 24 cases (49.0%) at L4-L5, 19 cases (38.8%) at L5-S1, and 6 cases (12.2%) at L4-L5-S1. Type 3 lumbar lordosis was the most frequent (26 cases, 53.1%), followed by types 2 (12 cases, 24.5%), 1 (6 cases, 12.2%), and 4 (5 cases, 10.2%). The most common diagnosis was degenerative disc disease (DDD) in 41 cases (83.7%) and degenerative spondylolisthesis in 8 cases. Pearson's correlation test showed a significant correlation between pre- and postoperative lumbar lordosis measurements, both global and segmental. This suggests that an increase in preoperative lumbar lordosis delta is associated with a corresponding postoperative delta increase. Conclusion: This study demonstrated that lumbar lordosis delta is correlated with postoperative lumbar fusion radiographic outcomes. A high lumbar lordosis delta indicates greater spinal flexibility, which may reduce the need for additional invasive procedures during surgery. These results highlight the importance of preoperative spinal flexibility assessment, including lumbar lordosis delta, for a more personalized and effective approach to surgery for degenerative lumbar disorders. Agoston Jakab Pokorni 1,2 , Máté Turbucz 1 , Rita Maria Kiss 3 , Aron Lazary 1,4 , Peter Eltes 1,4 1 National Center for Spinal Disorders, In Silico Biomechanics Laboratory, Budapest, Hungary , 2 Semmelweis University, School of PhD Studies, Budapest, Hungary , 3 Budapest University of Technology and Economics, Faculty of Mechanical Engineering, Department of Mechatronics, Optics and Mechanical Engineering Informatics, Budapest, Hungary , 4 Semmelweis University, Department of Orthopaedics, Department of Spine Surgery, Budapest, Hungary Introduction: Total en bloc spondylectomy (TES) effectively treats spinal tumors. The surgery requires a vertebral body replacement (VBR), for which several solutions were developed, whereas the biomechanical differences between these devices still need to be completely understood. This study aimed to compare a femur graft (FEM-GRAFT-C), a polyetheretherketone implant (PEEK-IMP-C), a titan mesh cage (MESH-C), and a polymethylmethacrylate replacement (PMMA-C) using a finite element model of the lumbar spine after a TES of L3. Material and Methods: The models with different VBRs were compared under the same loads. The lower endplate of the L5 vertebra was fixed, while a follower load of 400 N and a moment of 7.5 Nm were applied through the upper endplate of the L1 vertebra to simulate the effect of upper body weight and muscle force in flexion-extension, lateral bending, and axial rotation. The comparison evaluated the rotational stiffness of the structure, the segmental range of motion, and the distribution and maximum of the von Mises stress in the bony endplates of the L2 and L4 vertebrae adjacent to the vertebral replacements. Results: All models provided adequate initial stability by increasing the rotational stiffness and decreasing the ROM between L2 and L4. The PMMA-C had the highest stiffness for flexion-extension, lateral bending, and axial rotation (215%, 216%, and 170% of intact model), and it had the lowest segmental ROM in the instrumented segment (0.2°,0.5°, and 0.7°, respectively). Maximum endplate stress was similar for PMMA-C and PEEK-IMP-C but lower for both compared to MESH-C across all loading directions. Conclusion: These results suggest that MESH-C has the highest risk of subsidence and that PMMA-C had similar or better primary spinal stability than other VBRs, which may be related to the larger contact surface and the potential to adapt to the patient’s anatomy. Máté Turbucz 1 , Benjamin Hajnal 1,2 , Agoston Jakab Pokorni 1,2 , Peter Varga 3 , Áron Lazáry 3,4 , Peter Eltes 1,3,4 1 National Center for Spinal Disorders, Buda Health Center, In Silico Biomechanics Laboratory, Budapest, Hungary , 2 Semmelweis University, School of PhD Studies, Budapest, Hungary , 3 National Center for Spinal Disorders, Buda Health Center, Budapest, Hungary , 4 Semmelweis University, Department of Orthopaedics, Department of Spine Surgery, Budapest, Hungary Introduction: Following total sacrectomy, lumbopelvic reconstruction is essential to restore continuity between the lumbar spine and pelvis. Although many lumbopelvic reconstruction techniques (LPRTs) have been previously analyzed, the biomechanical effect of lumbopelvic distance reduction (LPDR) has not been investigated yet. Out aim was to evaluate and compare the biomechanical properties of four LPRTs while considering the effect of LPDR using the finite element (FE) method. Material and Methods: The FE models following total sacrectomy were developed to analyze four LPRTs, with and without LPDR. The closed-loop reconstruction (CLR), the sacral-rod reconstruction (SRR), the four-rod reconstruction (FRR), and the improved compound reconstruction (ICR) techniques were analyzed. Lumbopelvic stability was assessed through the shift-down displacement and the relative sagittal rotation of L5, while implant safety was evaluated based on the stress values at the bone-implant interface and within the rods. Results: Regardless of LPDR, both the shift-down displacement and relative sagittal rotation of L5 consistently ranked the LPRTs as ICR < SRR < FRR < CLR, with ICR being the stiffest for both parameters. LPDR decreased both the shift-down displacement and the relative sagittal rotation values. Due to LPDR, the stress values at the bone-implant interface values were reduced by 31% in flexion, by 17% in extension, by 29% in lateral bending, and by 29% in axial rotation. In addition, LPDR lowered the stress values within the rods by 16% in flexion, by 9% in extension, by 11% in lateral bending, and by 12% in axial rotation. Conclusion: LPDR significantly improved both lumbopelvic stability and implant safety in all reconstruction techniques after total sacrectomy. LPDR reduced the shift-down displacement, the relative sagittal rotation of L5, and the stress values at the bone-implant interface. Furthermore, in the ICR and SRR techniques, LPDR decreased the maximum stress values within the rods. All four investigated LPRTs demonstrated suitability for lumbopelvic reconstruction, with the ICR technique exhibiting the highest lumbopelvic stiffness. Domenico Compagnone 1 , Riccardo Cecchinato 2 , Andrea Pezzi 2 , Francesco Langella 1 , Marco Damilano 1 , Daniele Vanni 1 , Andrea Redaelli 1 , Claudio Lamartina 1 , Pedro Berjano 1 1 IRCCS Ospedale Galeazzi Sant'Ambrogio, Milan, Italy , 2 University of Milan, Milan, Italy Introduction: This study aims to evaluate the biomechanical variations of the spine in healthy adults based on the Roussouly classification, using radiographic analysis. The Roussouly classification describes four distinct types of spinal alignment, and understanding these variations is crucial for improving outcomes in spinal deformity surgery. Material and Methods: A retrospective analysis was performed on 125 adults who underwent EOS radiographic imaging. Participants were aged 18 to 50 and had no history of spinal or orthopedic diseases. Radiographic parameters were collected. Spines were classified according to the Roussouly classification (Types 1-4), and data were statistically analyzed using SPSS to determine differences in spinal morphology. Results: The cohort consisted of 53 females and 72 males, with an average age of 30.4 years. Significant differences in spinopelvic alignment were observed between Roussouly types. Linear regression analysis showed variability in lumbar lordosis across Roussouly types for similar pelvic incidence values. - Comparison between Roussouly type 1 and Type 2 . Type 1 spines have a greater lower lumbar lordosis (LLL) at 39° compared to 31°. Type 1 spines show a higher percentage of lordosis concentrated in the lower lumbar area, 77% versus 63% in Type 2. The lordosis between L5 and S1 is also higher in Type 1 at 23°, compared to 15° in Type 2. Furthermore, very interestingly the mismatch between pelvic incidence and lumbar lordosis (PI-LL) is greater in Type 1: a different LL may be physiological for the same PI, related to the spinal morphotype. - Comparison between Roussouly Type 3, Type 3A and Type 4 . The premise for classifying a spine as Type 3A is a PT remarkably low, at 1° (SD 3.0) in our cohort, contrasting with Type 3's 11° (SD 4.2). LL is greater in Type 3A, measuring 67° (SD 5.9) compared to 62° (SD 4.9) in Type 3. The LLL is also slightly higher in Type 3A at 41° (SD 5.5) compared to 38° (SD 5.0) in Type 3. Both types have similar percentages of lower lumbar lordosis (%_LLL), with Type 3A at 62% (SD 10) and Type 3 at 62% (SD 7.0). The PI-LL mismatch is significantly more negative in Type 3A at -23 (range -45 to -11) compared to -11 (range -24 to 1) in Type 3. Type 4 is quite similar to the Type 3 spinal shape, with a higher SS due to higher PI. Greater PI leads to greater magnitude of sagittal spinal curves with higher degrees of lumbar lordosis. The higher PI and LL justify the upper localization of the IP (located in L3), which consequently leads to the different %_LLL (62 ± 7 in Type 3 vs. 53 ± 5.6 in Type 4). Conclusion: The study highlighted the biomechanical diversity of the spine, demonstrating that individuals with the same pelvic incidence may have different lumbar lordosis based on their Roussouly type. These findings underscore the importance of considering the Roussouly classification, not just PI, when planning surgical interventions, as it influences spinal biomechanics and stress distribution.

Ali Guven 1 , Lukas Schönnagel 1 , Erika Chiapparelli 1 , Gaston Camino-Willhuber 1 , Jiaqi Zhu 1 , Thomas Caffard1 1 , Artine Arzani 1 , Kyle Finos 1 , Isaac Nathoo 1 , Krizia Amoroso 1 , Jennifer Shue 1 , Andrew Sama 1 , Frank Cammisa 1 , Federico Girardi 1 , Alexander Hughes 1 1 Hospital for Special Surgery, New York, United States Introduction: The multifidus muscle is an important stabilizer of the lumbar spine. In lumbar foraminal stenosis (LFS), the compression of the segmental nerve can give rise to radicular symptoms and back pain. LFS can impede function and induce atrophy of the segmentally innervated multifidus muscle. The objective of the present study is to evaluate the relationship between LFS and multifidus muscle atrophy. Material and Methods: Patients with degenerative lumbar spinal conditions who underwent posterior spinal fusion for degenerative lumbar disease from December 2014 to February 2024 were analyzed. Multifidus fatty infiltration (FI) and functional cross-sectional area (fCSA) were determined at the L4 upper endplate axial level on T2- weighted MRI scans using dedicated software. Severity of LFS was assessed at all lumbar levels and sides using the Lee classification (Grade: 0 . 3). For each level, Pfirrmann and Weishaupt gradings were used to assess intervertebral disc disease (IVDD) and facet joint osteoarthritis (FJOA), respectively. Multivariable linear mixed models were run for the LFS grade of each level and side separately as the independent predictor of multifidus FI and fCSA. Each analysis was adjusted for age, sex, BMI, as well as FJOA and IVDD of the level corresponding to the LFS. Results: A total of 216 patients (50.5% female) with a median age of 61.6 years (IQR = 52.0 - 69.0) and a median BMI of 28.1 kg/m2 (IQR = 24.8 - 33.0) were included. Linear mixed model analysis revealed that higher multifidus FI (Estimate [Confidence interval] = 1.7% [0.1 - 3.3], p = 0.043) and lower fCSA (-18.6 mm2 [-34.3 . -2.6], p = 0.022) were both significantly predicted by only L2-L3 level LFS severity. Conclusion: The observed positive correlation between upper segment LFS and multifidus muscle atrophy points towards compromised innervation. This necessitates further research to establish the causal relationship and guide prevention efforts. Abdolhamid Khoshab 1 1 UVN FN, Neurosurgical, Ruzomberok, Slovakia Introduction: Traditional surgical management of lumbosacral spondylolisthesis is technically challenging and is associated with significant complications. The advent of minimally invasive surgical techniques offers patients treatment alternatives with lower operative morbidity risk. The combination of percutaneous pedicle screw reduction and an axial presacral approach for lumbosacral discectomy and fusion offers an alternative procedure for the surgical management of low-grade lumbosacral spondylolisthesis. Case presentation: 24 patients who had L5-S1 grade 2 spondylolisthesis and who presented with axial pain and/or lumbar radiculopathy were treated with a minimally invasive surgical technique. Under O-Arm guidance and spinal navigation, spondylolisthesis was reduced with a percutaneous pedicle screw system, resulting in interspace distraction. Then, an axial presacral approach with the AxiaLIF System was used to perform the discectomy and anterior fixation. Once the axial rod was engaged in the L5 vertebral body, further distraction of the spinal interspace was made possible by partially loosening the pedicle screw caps, advancing the AxiaLIF rod to its final position in the vertebrae, and retightening the screw caps. The operative time ranged from 140 to 185 minutes, and blood loss was minimal (40-50 mL). Indirect foraminal decompression and adequate fixation were achieved in all cases. All patients were ambulatory after surgery and reported relief from pain and resolution of radicular symptoms. No perioperative complications were reported, and patients were discharged in two to three days. Fusion was demonstrated radiographically in all patients at one-year follow-up. Conclusions: Percutaneous pedicle screw reduction combined with axial presacral lumbar interbody fusion offers a promising and minimally invasive alternative for the management of lumbosacral spondylolisthesis. Devender Singh 1 , Eeric Truumees 1 , Eva Moroz 1 , Ashley Duncan 1 , Qais Zai 1 , Matthew Geck 1 , John Stokes 1 , Morgan Laviolette 1 , Vik Kohli 1 1 Ascension Texas Spine and Scoliosis, Austin, United States Introduction: Effective postoperative pain management is vital for patients undergoing lumbar spinal fusion surgery, as it influences opioid consumption, recovery time, and overall patient outcomes. The Erector Spinae Plane (ESP) block has emerged as a promising technique for analgesia in this patient population. This study tests the null hypothesis that there is no difference in pain control between patients receiving ESP blocks and those who do not. This retrospective study aims to evaluate the efficacy of ESP blocks in postoperative pain management and their impact on opioid consumption, recovery times, and patient-reported outcomes in individuals undergoing 1 or 2 level posterior lumbar surgery. Material and Methods: The study included 38 patients who received ESP blocks and 108 patients who did not. Demographic, clinical, and patient-reported outcome data were collected and analyzed. Variables included age, BMI, gender distribution, employment status, comorbidity index (CI), smoking status, ASA score, levels treated, operative time, estimated blood loss, need for transfusion, opioid consumption (measured in morphine milligram equivalents - MME), length of hospital stay (LOS), postoperative ambulation distance, and pain scores (measured using the Visual Analog Scale - VAS). Results: Demographics were comparable between the ESP block and no-block groups, with no significant differences in mean age (50.2 vs. 49.1 years), BMI (33.6 vs. 31.4), gender distribution (63.4% vs. 58.7% female), employment status (67% vs. 63%), CI (1.05 vs. 1.08), or smoking rates (7.6% vs. 9.7%). Mean ASA scores (2.6 vs. 2.5) and levels treated (1.2 vs. 1.2) were similar. The ESP block group had a longer mean operating room time (294.9 ± 63.4 vs. 272.4 ± 72.5 min) but lower estimated blood loss (207.3 ± 190.4 vs. 220.7 ± 143.9 ml). A smaller percentage of patients in the ESP block group required transfusion (12.9% vs. 25%). Patients receiving ESP blocks had lower mean total MME (304.9 ± 296.4 vs. 327.1 ± 278.4) and mean MME/day (88.1 ± 60.8 vs. 94.7 ± 49.1). The ESP block group also had shorter mean LOS (2.8 ± 1.6 vs. 3.6 ± 2.2 days) and greater mean postoperative ambulation distances (day 0: 46.7 ± 34.2 vs. 22.7 ± 17.6 ft, day 1: 258.4 ± 244.3 vs. 238.1 ± 210.6 ft, day 2: 283.6 ± 238.5 vs. 261.7 ± 168.9 ft). Mean postoperative pain scores (VAS) were similar between the groups. Conclusion: This study suggests that Erector Spinae Plane (ESP) blocks may be effective in managing postoperative pain in patients undergoing lumbar spinal fusion surgery. The use of ESP blocks was associated with reduced opioid consumption, shorter hospital stays, improved ambulation, and comparable pain scores. Further research and prospective studies are needed to validate these findings and assess the long-term benefits of ESP blocks in this patient population. Devender Singh 1 , Eeric Truumees 1 , Ashley Duncan 1 , Eva Moroz 1 , Qais Zai 1 , John Stokes 1 , Matthew Geck 1 , Morgan Laviolette 1 , Vik Kohli 1 1 Ascension Texas Spine and Scoliosis, Austin, United States Introduction: Prescription Drug Monitoring Programs (PDMPs) databases allow physicians to have real time information regarding a patient’s narcotic, sedative, and stimulant prescriptions. The NARX score, ranging from 000-999, gives an overview of current and past prescriptions, number of prescribers and overlapping prescriptions and morphine milligram equivalents (MME). This study’s aim was to see how NARX scores correlated with patient reported outcomes (PROs) in patients who underwent one- or two-level lumbar fusions. Material and Methods: Retrospective analysis of patients who underwent a one- or two-level lumbar fusion. 24 independent variables were collected, including general demographics, social histories, Charlson Comorbidity Index (CCI) scores, surgical, and postoperative MME data. Oswestry Disability Index (ODI), Pain Visual Analog Scale (VAS) and PROMIS Physical Function (PF), Pain Interference (PI) and Satisfaction with Social Roles (SR) were collected preoperatively and at various post-operative intervals up to 1 year. Revision and complication data was also collected. Results: Two cohorts were created based on NARX score distribution. There were 98 patients in the NARX ≤ 200 and 69 patients in NARX > 200. The cohorts were similar in age and BMI, but the higher NARX cohort had more females and also had higher uses of nicotine, Marijuana and daily alcohol consumption than their counterparts. Both cohorts had very similar surgical data, but the higher NARX cohort consumed higher MMEs during their inpatient stay despite no difference in length of stay. Higher NARX score patients were more likely to have a diagnosed psychiatric diagnosis and visit the Emergency Department during their post-operative recovery period. While both groups reported improvements in their PROs, patients with lower NARX scores had a more improvement in ODI and VAS than patients with higher NARX scores. Lower NARX scores patients reported comparatively more improvement in the PROMIS PF, PI and SR domains. Conclusions: Higher NARX scores in post-op one or two level lumbar fusion was associated with female sex and social history positive for nicotine, marijuana and daily alcohol consumption. These patients were significantly more likely to have a psychiatric diagnosis, consume more MME during inpatient recovery and visit the ED during their postop recovery. Lower NARX scores were associated with more significant improvement in disability and pain PROs. The results of this study support the pre-operative consideration of NARX score in conjunction with social histories and psychiatric comorbidities in the treatment decision making process. High NARX score patients should consider pre-operative optimization efforts such as opioid weaning, preoperative counseling, and other psychosocial support. Additionally, these data can be used in post-operative expectation management. Devender Singh 1 , Eeric Truumees 1 , Eva Moroz 1 , Ashley Duncan 1 , Qais Zai 1 , John Stokes 1 , Matthew Geck 1 , Morgan Laviolette 1 , Vik Kohli 1 1 Ascension Texas Spine and Scoliosis, Austin, United States Introduction: The Oswestry Disability Index (ODI) and Patient Reported Outcomes Measurement Information Systems (PROMIS) domains are common patient-reported assessment tools used in the evaluation of spine interventions. Previous studies have aided in developing crosswalks between ODI and the different PROMIS domains. The aim of this study is to determine correlation of measures pre-operatively (pre-op) in patients undergoing spinal fusion for degenerative lumbar disease and determine any patterns in demographics that could contribute to establishing benchmarking data that could aid in preoperative counseling and surgical decision making. Material and Methods: Retrospective data collection and analysis of patients completing pre-op ODI and PROMIS Physical Function (PF), Pain Interference (PI) and Satisfaction in Social Roles (SR) prior to lumbar fusion for degenerative spine disease. Results: 140 patients’ charts were reviewed. Group I (ODI 58). Group I consisted of 37 patients with a mean age 66.4 ± 11.9 years and 50% female; Group II had 69 patients with a mean age of 68.1 ± 9.6 years and 58% female; Group III had 34 patients with a mean age of 59.5 ± 11.3 years and 50% female. Mean age of Group III was significantly younger than Groups I and II. In addition to the higher ODI scores, Group III had lowest mean PF (28.4 ± 4.4) and SR (31.6 ± 5.0) PROMIS scores as well as highest mean PI (72.4 ± 4.7) scores. Negative correlations existed, as expected, across all Groups between ODI vs. PF, and ODI vs. SR, whereas a positive correlation was observed between ODI vs. PI across all groups as well. Conclusions: Patients with the highest self-reported disability and pain interference scores, were significantly younger than patients with lower ODI and PI scores. These younger patients also reported lower physical function and dissatisfaction in social roles than the other patients. This study supports the observation that higher self-reported pain scores are increasingly being seen in younger spine populations. Devender Singh 1 , Eeric Truumees 1 , Eva Moroz 1 , Ashley Duncan 1 , Qais Zai 1 , Matthew Geck 1 , John Stokes 1 , Morgan Laviolette 1 , Vik Kohli 1 1 Ascension Texas Spine and Scoliosis, Austinb, United States Introduction: The Oswestry Disability Index (ODI) and Patient Reported Outcomes Measurement Information Systems (PROMIS) domains are common patient-reported assessment tools used in the evaluation of spine interventions. Previous studies have aided in developing crosswalks between ODI and the different PROMIS domains. The aim of this study is to determine correlation of measures pre-operatively (pre-op) in patients undergoing microdiscectomies or decompressions for degenerative lumbar disease and determine any patterns in demographics that could contribute to establishing benchmarking data that could aid in preoperative counseling and surgical decision making. Material and Methods: Retrospective data collection and analysis of patients completing pre-op ODI and PROMIS Physical Function (PF), Pain Interference (PI) and Satisfaction in Social Roles (SR) prior to lumbar microdiscectomy or decompression for degenerative spine disease. Results: 158 patients’ charts were reviewed. Group I (ODI 58). Group I consisted of 40 patients with a mean age 59.5 ± 15.8 years and 46.7% female; Group II had 77 patients with a mean age of 60.3 ± 15.5 years and 46.3% female; Group III had 41 patients with a mean age of 51.7 ± 15.8 years and 35.5% female. Mean age of Group III was significantly younger than Groups I and II. In addition to the higher ODI scores, Group III had lowest mean PF (25.2 ± 4.6) and SR (31.1 ± 5.6) PROMIS scores as well as highest mean PI (73.2 ± 3.9) scores. Negative correlations existed, as expected, across all Groups between ODI vs.PF, and ODI vs. SR, whereas a positive correlation was observed between ODI vs. PI across all groups as well. Conclusions: Patients with the highest self-reported disability and pain interference scores, were significantly younger than patients with lower ODI and PI scores. These younger patients also reported lower physical function and dissatisfaction in social roles than the other patients. This study supports the observation that higher self-reported pain scores are increasingly being seen in younger spine populations. Yilin Lu 1,2,3 , Junyu Li 1,2,3 , Yongqiang Wang 1,2,3 , Xiang Zhang 1,2,3 , Weishi Li 1,2,3 , Miao Yu 1,2,3 1 Peking University third Hospital, Beijing, China , 2 Engineering Research Center of Bone and Joint Precision Medicine, Beijing, China , 3 Beijing Key Laboratory of Spinal Disease Research, Beijing, China Objective: To investigate the surgical risk of different GAP grades and the predictive value of GAP score on long-term complications and MCID achievement. Methods: 138 patients were included in the study. Imaging data and clinical report scores (low back pain, leg pain, JOA, SF-36 scores, etc.) were collected before, immediately after surgery and at the last follow-up. For statistical analysis, independent sample t test or randomization test was used for continuous variables and chi-square test was used for categorical variables. Results: The overall spine-pelvic parameters of the patient were significantly improved compared with those before surgery. Based on the post-op GAP score, 16 (11.59%) patients were classified as Proportioned (P), 53 (38.41%) as Moderately Disproportioned (MD), 16 (11.59%) patients were classified as proportioned (P), 53 (38.41%) as moderately disproportioned (MD), and 69 (50%) as Severely Disproportioned (SD). The number of minor complications in group P was significantly higher than that in the other two groups (P: 2.94, MD: 1.98, SD: 1.78), but there was no significant difference in other perioperative findings. At the last follow-up, the rate of MCID of low back pain and leg pain was significantly higher in group P, while the incidence of PJK was not significantly different. Conclusions: For DLS patients, achieving a better GAP score after surgery does not affect perioperative safety, and can maximize the quality of life during follow-up. The correlation between GAP score and long-term mechanical complications needs further study. Stone Sima 1 , Victor Martin-Gorgojo 2 , Sam Lapkin 3 , Zachary Gan 1 , Brian Hsu 2 , Ashish Diwan 4 1 St George and Sutherland Clinical School, Spine Labs, Sydney, Australia , 2 NSW Spine Specialists, Sydney, Australia , 3 Southern Cross University, Gold Coast, Australia , 4 Spine Service, Department of Orthopaedics, St George Hospital, Sydney, Australia Introduction: Understanding the complex nature of low back pain (LBP) is crucial for effective management. The PainDETECT questionnaire is a tool that distinguishes between neuropathic (NeP) and nociceptive (NoP) low back pain. Traditionally NeP and NoP have been primarily attributed to patho-anatomical abnormalities within the lumbar spine. However, increasing evidence points to multifaceted involvement, encompassing a range of physical, biomechanical, chemical, and psychosocial factors. The study aimed to determine the independent relationship between NeP as assessed by the PainDETECT questionnaire and non-spinal comorbid medical conditions. Methods: A prospective cohort study was conducted involving 400 patients suffering from chronic LBP (> 6 months), aged > 18 years, who complete the PainDETECT questionnaire and provided responses regarding the presence of any comorbid conditions. Patients were excluded if they had a history of lumbar spinal surgery, were diagnosed with specific pathologies spinal pathologies or if they had spinal deformities. A binary logistic regression model was used to analyse the confounding status of comorbid medical conditions and pain severity measured by NRS to determine independent relationships between specific conditions and neuropathic pain. Results: The study included 143 and 257 patients suffering from NeP and NoP, respectively. The NeP group had a 38% higher mean numerical rating scale score compared to the NoP group (8.10 ± 1.55 vs. 5.86 ± 2.26, p < 0.001). The odds of developing NeP were 2.9 Exp(B) = 2.844, 95%C.I. [1.426-5.670], p < 0.01), 2.7 (Exp(B) = 2.726, 95%C.I. [1.183-6.283], p < 0.05) and 2.8 (Exp(B) = 2.847, 95%C.I. [1.473-5.503], p < 0.05) times higher in patients suffering from gastrointestinal conditions, rheumatoid arthritis, and depression, respectively. Conclusion: NeP as determined by the PainDETECT questionnaire, is associated with gastrointestinal conditions, rheumatoid arthritis, and depression. This pioneering study has shed light on the potential involvement of the gut microbiome as a common factor connecting non-spinal comorbidities and NeP. However, future prospective cohort studies are needed to incorporate advanced analytical techniques, such as next-generation sequencing for RNA expression analysis of gut and IVD microbiomes. These findings underscore the importance of formulating personalized management plans tailored to individual pain and medical profiles, rather than relying on a blanket approach to pain management. Anton Denisov 1,2 1 Hospital CEMTRO, Madrid, Spain , 2 The Taylor Collaboration Research Center, San-Francisco, United States Introduction: In the last decade, the popularity of anterior lumbar interbody fusion (ALIF) has increased compared to posterior lumbar interbody fusion (TLIF and PLIF). But in fact, anterior techniques has many grave complications that could lead to permanent disability or mortal existus. For this way it was recollected recent studies that contemplate clinical results of both approaches. But, by the author was observed that many of them lacks of appropriate statistical and methological component that give a effort to provide more fiable information about this problem. That is why it was decided to carry out a new systematic analysis with a new meta-analysis. Material and Methods: Direct, Wiley Online Library and Medline databases were searched for published scientific papers over the last 8 years (2015.2024) for randomized controlled and observational studies, including retrospective and prospective studies. Studies with patients with DDSD or spondylolisthesis up to Meyerding grade 2 were analyzed. Keywords as «ALIF», «Anterior spondylodesis», «ALIF complication rate», «PLIF», «Posterior spondylodesis», «PLIF complication rate», «TLIF», «Transforaminal spondylodesis», «TLIF complication rate» were used. Was included 12 articles suit to inclusion criteria. Only intra and postoperative complications were taken into account (according to Schwab 2012). Results: The detailed characteristics of the studies presented with summaries. General complication rate is much lower in anterior surgery group (RR 0.89 (0.43, 0.97), but the nature of this complications is different. There is no publication beas observed (Egger's test and Funnel plot assessment provided). Conclusion: Meta-analysis can only make paired comparisons and cannot include trials with multiple groups. The characteristics of complications in anterior and posterior spinal fusion are different, which complicates the analysis. Insufficient number of studies and their heterogeneity, makes the resulting assessment difficult. Adnene Benammou 1,2 , Souha Bennour 1,2 , Seddik Akremi 1,2 , Rebh Hamada 2 , Yasmine Ben Abdeladhim 1,3 , Mehdi Bellil 1,2 , Mohamed Ben Salah 1,2 1 University Tunis el Manar, Faculty of Medecine of Tunis, Tunis, Tunisia , 2 Charles Nicolle Hospital, Orthopedic Surgery Department, Tunis, Tunisia , 3 Charles Nicolle Hospital, Radiology Department, Tunis, Tunisia Introduction: Posterior and transforaminal lumbar interbody fusion techniques have long been used to treat degenerative disk disease at the L5S1 level. However, these techniques are associated with certain drawbacks such as kyphotic deformities nonunion and some bad results with S1 screws. With the rise of minimally invasive techniques Anterior Lumbar Interbody Fusion (ALIF) is an alternative technique with low rates of complications. The aim of our study was to evaluate the clinical and radiological outcomes of ALIF in degenerative disk disease Material and Methods: A retrospective descriptive monocentric study was lead between 2014 and 2022 including patients treated with ALIF for degenerative disk disease at the L5-S1 level. Data was collected from medical files including epidemiological data clinical data notably main complaints neurological status pre and post operatively pain levels using the VAS and the ODI Score, and blood loss estimated via the hemoglobin levels. Radiological parameters collected were segmental and regional lordosis and the disk height. Complications were noted preoperatively and at last follow up. Results: Twenty-five patients were treated by ALIF for degenerative disk disease. The mean age was 59.8 and the mean follow up was at 2.4 years. All patients presented with back pain with radiculopathy associated in 80% of cases. Only 2 patients presented with focal deficit at time of surgery. A CT Angio was used in 20 patients in the planification process. Segmental lordosis increased from 12.33 to 16 postoperatively and global lordosis from 45 to 49. Disk height significantly increased from 0.61 to 1.33 (p = 0.02). ODI Score improved from an average of 45% to 15%. No major vascular complications were noted, and one case of erectile dysfunction was reported . Major vascular complications are rare in literature and the rates of retrograde ejaculation can reach 2%. Conclusion: ALIF is a minimally invasive alternative for L5-S1 degenerative disc disease. It can achieve a restoration of the lordosis, of the disk height, a decrease in pain and an improvement in clinical scores with low complication rates. Adnene Benammou 1,2 , Souha Bennour 1,2 , Seddik Akremi 1,2 , Habib Sanaa 1,2 , Mehdi Bellil 1,2 , Mohamed Ben Salah 1,2 1 University Tunis el Manar, Faculty of Medecine of Tunis, Tunis, Tunisia , 2 Charles Nicolle Hospital, Orthopedic Surgery Department, Tunis, Tunisia Introduction: Anterior Lumbar Interbody Fusion (ALIF) is an alternative treatment technique for several spinal pathologies mainly degenerative disk disease. However, the classical supine position may be problematic is obese patients with the lack of access to L5-S1 level and higher risk of vascular and visceral complications. Lateral ALIF can offer an alternative to compensate these difficulties. The aim of our study was to evaluate the advantages of each position in ALIF surgery. Material and Methods: A Retrospective descriptive monocentric study was lead between January 2020 and December 2022 including patients treated with ALIF for Degenerative disc disease with a minimum follow-up of 12 month. Data was collected from medical files with focus on age, BMI, peroperative positioning supine or lateral, operative time and estimated blood loss. Functional results were noted pre and postoperatively based on the VAS and the Oswestry Disability Index (ODI). Radiological results were based on lumbar spine X rays. Segmental lordosis and global lordosis disk height were noted pre and post operatively. Cage positioning errors were also looked for. MRI was used for the planification process to locate the aortic bifurcation and to measure the umbilicus to aorta distance. Vascular and visceral complications were noted. Results: Twenty-five patients were treated with ALIF between 2020 and 2022 for degenerative disk disease . 14 patients in the Supine position (Group 1) and 11 in the lateral position (Group 2). All patients had an ALIF for the L5-S1 level. One patient had an L5-S1 ALIF with OLIF L3-L4, L4-L5 in the same surgery, plus a posterior fixation. Two patients needed a posterior fixation in a second stage surgery patients treated in the lateral position had significantly higher BMI (p < 0.001) and umbilicus to aorta distance (p < 0.001) . The operative time was lower in the 2nd group but with no statistically significant difference . There was no statistically significant difference in functional and radiological results between the two groups . One case of cage malposition was noted in the second group needing a second intervention. No major vascular or visceral complications were noted in the two groups. Conclusion: While Outcomes of ALIF in supine or lateral decubitus are comparable, lateral ALIF can be recommended for: Obese patients with high BMI and high umbilicus-aorta distance or in cases where Multilevel fusion is needed. Adnene Benammou 1,2 , Marwen Hadj Romdhane 1,3 , Seddik Akremi 1,2 , Habib Sanaa 1,2 , Yasmine Ben Abdeladhim 1,3 , Mehdi Bellil 1,2 , Mohamed Ben Salah 1,2 1 University Tunis el Manar, Faculty of Medecine of Tunis, Tunis, Tunisia , 2 Charles Nicolle Hospital, Orthopedic Surgery Department, Tunis, Tunisia , 3 Charles Nicolle Hospital, Radiology Department, Tunis, Tunisia Introduction: The lower dorsal and lumbar spine is prone to various traumatic and degenerative pathologies requiring osteosynthesis techniques, particularly posterior pedicle screw fixation. The study of pedicle morphometry preoperatively allows us to identify the anatomical landmarks for a precise and safe surgery. Our aim was to assess the pedicle morphology in the lower thoracic and lumbar spine (T10-L5) in an adult Tunisian population. Material and Methods: It was a monocentric, descriptive, observational, cross-sectional study of 100 individuals who met the inclusion criteria and underwent CT scans of the lower dorsal and lumbar spine. We excluded subjects with traumatic, degenerative, inflammatory and/or infectious lesions of the lower dorsal and lumbar spine as well as those with postoperative sequelae. Results: We found that the vertebral pedicles of the lower dorsal and lumbar spine in our sample had an average length of 43.44 mm (±4.15), a thickness of 7.6mm (±3.3), and a transverse angulation that was always anteromedial in T10 and in the lumbar spine, sometimes anterolateral or neutral in T11 and T12 with an average of +10.55° (±7.59). We note&dacute; no difference between the right and left sides and between different age groups. We established a male superiority for the linear morphometric parameters and no significant difference between genders for the angular parameter. We obtained a very high intra-observer correlation and an improvement of the inter-observer agreement with time, showing the effect of training for the second observer. Conclusion: Pedicle screw fixation is the gold standard for instrumentation of the low dorsal and lumbar spine. Placement of these pedicle screws is associated with a significant risk of injury to the spinal cord, nerves and vascular structures. These lesions are essentially due to the narrowness of the pedicles, their anatomical variability and the proximitý of noble anatomical structures . To avoid these lesions, Surgeons therefore need to have an intimate knowledge of the anatomy of the thoraco-lumbar spine, and an appropriate preoperative assessment for each patient. This explains, among other things, the growing number of cadaveric and CT morphometric studies focusing on pedicle morphometry. The ethnic, interindividual, between spine levels and genders variability of pedicle morphometric parameters highlight the importance of preoperative computed tomography of the lower dorsal and lumbar spine to identify the anatomical landmarks for pedicle screw fixation. Clint Guitarte 1 1 Northern Mindanao Medical Center, Orthopaedics, Cagayan de Oro, Philippines Background: Pseudarthrosis is one of the most common complications of lumbar spine surgery. On average at least 15% of attempted spinal fusions result in pseudarthrosis. It is a known cause of recurrent pain and disability after spinal fusion surgery and is one of the most common indications for revision lumbar surgery. Despite its relatively high prevalence, there is a lack of robust clinical evidence on salvage options for lumbar pseudoarthrosis. Anterior lumbar interbody fusion (ALIF) is an attractive option for revision surgery of pseudarthrosis. Methods: This systematic review aims to determine the current evidence on Anterior Lumbar Interbody Fusion (ALIF) as a salvage surgical technique for lumbar pseudoarthrosis. PubMed/Medline, Google Scholar, and EMBASE were utilized for literature search. Results: In total, 318 studies were identified through database searching and other sources. After fulfilling the inclusion and exclusion criteria, only 4 studies were analysed. Patient enrolment spanned from 1984. 2016, amassing a total of 151 patients with lumbar pseudoarthrosis with mean age of 54.84 (30 . 81). The advantages of salvage ALIF include improvements in clinical and radiologic outcomes and a low complication rate after surgery: Fusion rates (100%, 95%, 96.6%, 72%); Segmental lordosis (6.23 vs 8.85), and disc height (12.25 vs 16.94) improvement at final follow-up; Overall mean improvements in the VAS (8 to 2.2; 7.25 to 3.1), ODI (54.5 to 21.2; 56.3 to 30.4), and SF12 scales (SF-12 PCS 32.2 to 41.1; SF-12 MCS 36.6 to 50.9). Reported complications include (5 vascular, 10 wound, 8 ileus, 1 hernia, 1 hematoma, 1 screw cut-out, 1 lateral femoral cutaneous neuropraxia, 1 hematuria, 8 pneumonia, 9 UTI, and 3 cardiac). Conclusion: In conclusion, this systematic review presented the evidence that ALIF is a useful for salvage surgery to treat lumbar pseudoarthrosis. Meng-Huang Wu 1,2 , Anh Tuan Bui 2 1 Taipei Medical University, Department of Orthopaedics, Taipei, Taiwan , 2 Taipei Medical University Hospital, Department of Orthopaedics, Taipei, Taiwan Background: Transforaminal lumbar interbody fusion (TLIF) is a most widely used surgical technique for addressing lumbar degenerative diseases. We have developed a fully computer-supported pipeline and a 3D printing model to predict cage height and the degree of lumbar lordosis subtraction from the pelvic incidence (PI-LL) following TLIF surgery. Methods: The artificial intelligence (AI) pipeline consisted of two primary stages. Firstly, a deep learning model was utilized to extract crucial features from X-ray images. Secondly, five machine learning algorithms were trained to identify the optimal models for predicting the interbody cage height and postoperative PI-LL. The different 20 cases were selected to construct the 3D printing model, which served as an external validation for the AI model. Results: The AI model internally predicted cage height with an RMSE of 1.01, accurately predicting 131 out of 311 cases (42.12%), with 1 mm errors in the remaining cases. For PI-LL prediction, it achieved an RMSE of 5.19 and an accuracy of 0.81 for PI-LL stratification. In external validation, the model correctly predicted cage height in 11 out of 20 cases (55%). RMSE and MAE for PI-LL prediction were 3.28 and 2.91, respectively, versus 5.19 and 3.86 in internal validation. In constructing the 3D printing model, it yielded RMSE and MAE values of 0.59 and 0.25, respectively, with an accuracy of 75%. For the prediction of PI-LL, the 3D model demonstrated lower RMSE and MAE values (2.62 and 2.02) than AI model. While there was no significant difference between AI and 3D printing in cage height prediction (p-value = 0.249), the models differed significantly in PI-LL prediction (p-value = 0.037). Conclusion: Our study demonstrated the significant potential of AI and 3D printing in enhancing the accuracy of TLIF surgeries. Cody Schlaff 1 , Sennay Ghenbot 1 , Brooke Smith 1 , Donald Fredericks, Jr. 1 , Melvin Helgeson 1 , Scott Wagner 1 , Alfred Pisano 1 1 Walter Reed National Military Medical Center, Orthopaedics, Bethesda, United States Introduction: Spondylolithesis is a common lumbar pathology that can cause mechanical back pain, radiculopathy, or neurogenic claudication. Both degenerative and isthmic spondylolisthesis untreated result in sagittal imbalance, which is commonly treated with interbody fusions such as, transforaminal lumbar interbody fusion (TLIF) or anterior lumbar interbody fusion (ALIF). Robust radiographic comparisons of TLIF vs ALIF in their power to correct sagittal imbalance is lacking. The objective of this study was to compare the power of both TLIFs and ALIFs in their ability to correct sagittal lumbar alignment and the effects each have on the lumbar spine in low grade spondylolisthesis at 1-year post-operatively. Material and Methods: A retrospective review of the Military Healthcare System (MHS) Database M2 was conducted for all available encounters from 2016. 2022 for patients with ICD10 diagnosis of spondylolisthesis who underwent surgical intervention. TLIF/PLIF or ALIF for Grade I or II degenerative or isthmic spondylolisthesis. Only patients with preoperative imaging within 1 year of surgical intervention and at least 1-year post-operative radiographs were considered for this study. Radiographic analysis included pelvic incidence (PI), pre- and post-operative pelvic tilt (PT), sacral slope (SS), global lumbar lordosis (GLL), segmental (L4-S1) lumbar lordosis (SLL), lordosis distribution index (LDI), PI-LL mismatch, index level lordosis (ILL), adjacent level cobb angle (ALC), and adjacent level disc height (ALD). Type of implant, post-operative follow-up time and patient demographics were also collected. Data analysis included 2-way ANOVA with Bonferroni post-hoc analysis, Fisher’s exact test and Welch’s t-test. Results: A total of 1,591 encounters were identified within M2 during the study period. Of these 475 and 125 encounters carried the ICD10 codes of degenerative spondylolisthesis and isthmic spondylolisthesis respectively. 94 patients underwent TLIF/PLIF (81 degenerative; 13 isthmic) and 29 underwent ALIF (17 degenerative; 12 isthmic) who met inclusion criteria. ALIFs generated greater SLL at 1-year compared to TLIFs regardless of lumbar pathology (41.4° (33.20 - 47.95) vs 31.90° (24.00 - 40.38)). ALIFs also demonstrated a greater redistribution of LDI compared to TLIFs at 1-year regardless of lumbar pathology (66.93% (60.20 - 72.37) vs. 56.37% (43.27 - 65.07) ) , as well as, for degenerative spondylolisthesis (66.57% (55.53 - 72.63) vs. 54.31% (40.87 - 65.40)). Type of implant had no effect on the redistribution of LDI post-operatively for degenerative spondylolisthesis who underwent TLIFs. Conclusion: ALIFs generate greater redistribution of lumbar lordosis to bring the LDI to a more physiologic distribution when compared to TLIFs at 1-year postoperatively regardless of whether patients have degenerative or isthmic spondylolisthesis. Additionally, ALIFs provide greater index level lordosis and segmental correction compared to TLIFs. ALIFs are a more powerful lordotic correction tool compared to TLIFs for low grade spondylolisthesis and surgeons should strongly consider their use in one/two level interbody corrective surgery. Rachael Tirjan 1 , Alex Tang 2 , Jeffrey Mun 1 , Adam Cole 1 , Russell Strom 3 , Tan Chen 4 1 Geisinger Commonwealth School of Medicine, Scranton, United States , 2 Geisinger Health, Orthopaedic Surgery Northeast Residency, Wilkes-Barre, United States , 3 Geisinger Health, Neurosurgery, Wilkes-Barre, United States , 4 Geisinger Health, Department of Orthopaedic Surgery, Wilkes-Barre, United States Introduction: It is widely accepted that unstable degenerative spondylolisthesis warrants fusion surgery, but there is no consensus on what constitutes instability, and thus the necessity of fusion remains controversial. Standing flexion-extension radiographs (XRs) have been traditionally used to assess ventral translation and stability of a spinal segment. This method, however, may not be reliable due to patient, technical and imaging factors, and may underestimate true instability in spondylolisthesis. The purpose of this study was to (1) compare translation on standing neutral, flexion, and extension XRs with supine MRI in patients with spondylolisthesis and (2) evaluate if anterior or posterior disc height is associated with ventral instability. Material and Methods: A retrospective review was performed identifying a consecutive cohort of patients who underwent one- or two-level fusion or decompression surgery for degenerative spondylolisthesis from 2020-2024. Anterior disc height (ADH), posterior disc height (PDH), and slip distance were measured on preoperative lateral lumbar XRs with the patient in standing neutral, flexion, and extension positions and on supine MRI. Delta (∆) XR.MRI was calculated as the difference in slip distance between XR and MRI with the patient in neutral, flexion, and extension when compared to supine. Descriptive and inferential statistics were performed. Results: A total of 137 patients with single or multilevel spondylolisthesis met inclusion criteria with a total of 185 spinal levels studied. Average follow-up time was 7.5 months. Mean slip distance measured on standing dynamic x-rays were significantly greater than on supine MRI (NeutralXR 5.2 mm, FlexXR 5.7 mm, ExtXR 5.6 mm, SupineMR 3.7 mm, p < 0.0001). The average slip difference between standing and supine positions was ∆NeutralXR-MR 1.57 mm, ∆FlexXR-MR 2.08 mm, and ∆ExtXR-MR 1.91 mm. Average ADH was 8.8 mm and PDH was 3.7 mm. Univariate and multivariate linear regression analyses, and Pearson’s tests demonstrated no correlation between ADH or PDH, and ∆NeutralXR-MR and ∆FlexXR-MR. A weak correlation was found between ∆ExtXR-MR, and ADH (-0.162, p = 0.028) and PDH (-0.179, p = 0.015). Conclusion: Instability in degenerative spondylolisthesis is often underestimated on traditional standing flexion-extension radiographs and may be better demonstrated in spinal positions that accentuate differences in intradiscal pressure. Our study found ventral instability was highest comparing standing flexion lumbar X-Ray and supine MRI, with a slip difference of more than 2mm. This method of measurement may provide a more reliable, sensitive and convenient method for reporting instability. Lastly, disc height was not found to be correlated with increased instability. Asham Khan 1 , Mohamed Soliman 1 , Esteban Quiceno Restrepo 1 , Jacob Greisman 1 , Isabelle Stockman 2 , Alexander Aguirre 1 , Jeffrey Mullin 1 , John Pollina 1 1 University at Buffalo Neurosurgery, Buffalo, United States , 2 Jacobs School of Medicine and Biomedical Sciences, Buffalo, United States Introduction: Degenerative Disc Disease (DDD) leads to significant spinal structural changes such as degeneration of the facets and the intervertebral discs which reduce the lumbar lordosis long term. The degree of these structural changes has not been studied extensively as a regulatory factor of the final post-operative lordosis after Extreme Lateral Interbody Fusion (XLIF). The authors aimed to review the role of DDD in the final lumbar lordosis after surgery. Materials and Methods: A retrospective review study was conducted from September 2015 to February 2017 including one to two levels XLIFs performed in our institution. All these cases were treated for symptomatic degenerative disc disease with implants of the same dimensions. The patients were stratified according to the degree of their DDD using the Pfirrmann and Parthia classifications. The authors collected data on patients’ demographics, BMI, pre-operative lordosis, pre-operative segmental lordosis, type of fixation, post-operative lordosis, and post-operative segmental lordosis. Results: Eighty patients were finally included (Age: 25-76 years old). Thirty-eight were males (47.5%). Forty-two cases (52.5%) were one-level XLIF. There were no intra-operative or post-operative complications. Blood loss was minimal (50-70 ml). Lumbar segmental lordosis and disc height were significantly improved in all our cases (p = 0.001). A significant interaction was found between the degree of DDD and pre-operative lordosis (p: .000 for Pfirrmann classification, p .001 for Parthia classification), as well as between DDD and post-operative lordosis (p: .009 for Pfirrmann classification, p .000 for Parthia classification). An analogous result was not observed in the study of segmental lordosis. Conclusions: The degree of lumbar DDD defined by Pfirrmann and Parthia classifications is an important factor for the calculation of the desirable correction of lumbar lordosis after XLIFs. Junyu Li 1 , Bowen Xie 2 , Peibo Sun 2 , Zhuo Ran Sun 3 , Yongqiang Wang 3 , Miao Yu 3 , Yan Zeng 3 , Lin Zeng 3 , Weishi Li 3 1 Peking University Third Hospital, Orthopedic Department, Beijing, China , 2 Peking University Health Science Center, Beijing, China , 3 Peking University Third Hospital, Beijing, China Introduction: Degenerative lumbar scoliosis (DLS) is a prevalent spinal condition in the elderly, with an incidence of approximately 2%-68%. Pelvic obliquity (PO), a sign of coronal imbalance, is frequently observed in patients. PO can cause joint deterioration and aberrant gait, which can have a significant negative impact on the patient's quality of life. The objectives of this study were to propose a novel classification of preoperative PO in DLS patients and to discuss how this PO classification could guide corrective surgery for scoliosis. Material and Methods: Patients with PO (POA ≥ 3°) were divided into type I and type II groups. The higher iliac spine of the pelvis was congruent with the direction of the C7 plumb line (C7PL) offset in type I, whereas in type II, the higher iliac spine was opposite to the direction of the C7PL offset. A comparative analysis was performed between the preoperative and postoperative radiological parameters and patient-reported outcomes of various patient types. Results: Patients with PO (POA ≥ 3°) were divided into type I and type II groups. The higher iliac spine of the pelvis was congruent with the direction of the C7 plumb line (C7PL) offset in type I, whereas in type II, the higher iliac spine was opposite to the direction of the C7PL offset. A comparative analysis was performed between the preoperative and postoperative radiological parameters and patient-reported outcomes of various patient types. Conclusion: Patients can be categorized into types I and II based on the proposed classification of PO and should adopt different surgical strategies accordingly. Improvement in the Cobb angle and AVT during surgery are important for correcting Type I PO, while Intraoperative SOA correction and fixation to the sacrum in Type II patients are more crucial for restoring long-term pelvic balance. Julius Gerstmeyer 1,2,3 , Anna Gorbacheva 2 , Clifford Pierre 1,2 , Daniel Norvell 4 , Tara Heffernan 2 , Arash Tabesh 2 , Thomas Schildhauer 3 , Amir Abdul-Jabbar 1,2 , Rod Oskouian 1,2 , Jens Chapman 1,2 1 Swedish Neuroscience Institute, Seattle, United States , 2 Seattle Science Foundation, Seattle, United States , 3 BG University Hospital Bergmannsheil, Department of General and Trauma Surgery, Bochum, Germany , 4 Spectrum Research Inc , Tacoma, United States Objective: Degenerative spondylolisthesis and spinal canal stenosis are some of the more common clinical conditions associated with low back pain. Various surgical techniques ranging from a standalone decompression techniques to fusion have been proposed in the past. Interspinous spacer devices (ISD) have been introduced as an intermediary surgical option. The aim was to compare the 90-day all-cause readmission rates between techniques, with secondary outcomes including total hospital charges and post-operative complications. Methods: Utilizing the 2020 Nationwide Readmission Database (NRD), adult patients (> 18 years) were selected by primary diagnosis ICD-10 code for spondylolisthesis and/or spinal stenosis. Patients were categorized by their surgical treatment: ISD, decompression, or single-level posterior fusion. Treatment techniques were compared using a multivariable logistic and linear regression while adjusting for potential confounding factors. Propensity score adjustments were performed as a sensitivity analysis. Results: In total 37,503 patients met our inclusion criteria, with the majority receiving decompression (81.2%), followed by fusion (18.3%) and ISD (0.49%). The 90-day all-cause readmission rates were 8%, 9%, and 9% respectively (p = 0.85). ISD had the lowest mean hospital charges at $109,676, compared to $118,510 for decompression and $205,024 for fusion (p < 0.001). Complication rates were similar across all groups, aside from significant differences in neurological and gastrointestinal complications. Several medical comorbidities were identified as risk factors for readmission. Conclusion: ISD had lower hospital charges with comparable readmission and complication rates versus decompression or fusion surgeries. Our results suggest that ISD may be cost-effective relative to more traditional surgical techniques for spondylolisthesis or spinal stenosis. Further research into the long-term cost-effectiveness and clinical outcomes will be needed. Christopher Chaput 1 , Gonzalo Mariscal 2 , John O'Toole 3 , Michael Steinmetz 4 , Paul Arnold 5 , Christopher Witiw 6 , Bradley Jacobs 7 , James Harrop 8 1 UT Health San Antonio, Department of Orthopedics, San Antonio, United States , 2 Institute for Research on Musculoskeletal Disorders, Valencia Catholic University, Valencia, Spain , 3 Rush University Medical Center, Chicago, United States , 4 Cleveland Clinic Lerner College of Medicine, Neurological Institute, Department of Neurosurgery, Cleveland, United States , 5 Loyola University Chicago, Department of Neurological Surgery, Chicago, United States , 6 University of Toronto, Department of Surgery, Division of Neurosurgery, Toronto, Canada , 7 University of Calgary, Department of Clinical Neurosciences, Calgary Spine Program, Calgary, Canada , 8 Thomas Jefferson University, Department of Neurological Surgery, Department of Orthopedic Surgery, Philadelphia, United States Introduction: Pseudoarthrosis after spinal fusion surgery is a prevalent adverse event, imparting substantial clinical and economic burden also leading to lower patient-reported outcomes. Smoking is a modifiable risk factor for impairing bone healing, but its definitive impact on clinical outcomes and patient-reported outcome measures (PROM) remains unknown. This systematic review with meta-analysis is aimed at evaluating the impact of smoking on spinal fusion rates and the resulting PROMs. Material and Methods: Following the PRISMA guidelines, a systematic literature search was conducted in PubMed, EMBASE, Scopus, and the Cochrane Library without date or language restrictions. The search strategy included the following terms: (spinal fusion OR fusion rate OR spine failure) AND (smoking OR tobacco OR cigarette smoking). Studies were selected using the PICOS criteria: Patients - Adults undergoing spinal fusion; Intervention - Smokers; Comparator - Non-smokers; Outcomes - Non-union rate, pseudoarthrosis, and patient-reported outcome measures (PROMs); Study Design - Comparative studies. The primary outcomes assessed were non-union/pseudoarthrosis incidence and PROMs, including VAS, ODI, EQ-5D, SF-12, SF-36, return to work, and satisfaction measured by the North American Spine Society Lower Back Pain instrument. Odds ratios (ORs) were calculated for dichotomous variables and mean differences or standardized mean differences for continuous variables. Results: A total of 29 studies were included in this analysis. The unadjusted incidence of pseudoarthrosis was significantly higher in smokers than in non-smokers (odds ratio [OR] 1.97, 95% confidence interval [CI] 1.55 to 2.52, p < 0.001). Subgroup analysis revealed significant differences in the cervical (OR 2.09, 95% CI 1.27 to 3.44, p < 0.05) and lumbar (OR 1.97, 95% CI 1.45 to 2.68, p < 0.001) regions. Adjusted analysis also showed a significantly higher incidence of pseudoarthrosis in smokers (OR 1.38, 95% CI 1.12 to 1.72, p < 0.05). Patient ODI, VAS, EQ-5D, and SF-12 and SF-36, consistently favored nonsmoking patients. Smoking was associated with a lower rate of returning to work (OR 0.70, 95% CI 0.54 to 0.90, p < 0.05) and reduced satisfaction (OR 0.24, 95% CI 0.12 to 0.49, p < 0.001). Former smokers (smoking cessation for at least 1 year prior to surgery) did not show significant differences compared to nonsmokers in terms of nonunion rate or pain scores. Conclusion: Smoking is associated with an increased risk of nonunion and lower PROM after spinal fusion surgery. Healthcare providers should emphasize smoking cessation interventions to improve surgical outcomes and patient satisfaction. Gonzalo Mariscal 1 , John O'Toole 2 , Christopher Chaput 3 , Michael Steinmetz 4 , Paul Arnold 5 , Christopher Witiw 6 , Bradley Jacobs 7 , James Harrop 8 1 Institute for Research on Musculoskeletal Disorders, Valencia Catholic University, Valencia, Spain , 2 Rush University Medical Center, Chicago, United States , 3 UT Health San Antonio, Department of Orthopedics, San Antonio, United States , 4 Cleveland Clinic Lerner College of Medicine, Neurological Institute, Department of Neurosurgery, Cleveland, United States , 5 Loyola University Chicago, Department of Neurological Surgery, Chicago, United States , 6 University of Toronto, Department of Surgery, Division of Neurosurgery, Toronto, Canada , 7 University of Calgary, Department of Clinical Neurosciences, Calgary Spine Program, Calgary, Canada , 8 Thomas Jefferson University, Department of Neurological Surgery, Department of Orthopedic Surgery, Philadelphia, United States Introduction: Obesity, a growing global public health concern, has been linked to medical and surgical complications in orthopedics and traumatology. Existing evidence on the association of obesity and spinal surgery is inconsistent, highlighting the need for a pooled meta-analysis. This study aimed to assess the impact of obesity on incidence of spinal nonunion, patient-reported outcome measures (PROMs) and costs. Material and Methods: A systematic search was conducted in four databases. Studies comparing obesity versus non-obesity in patients undergoing spinal fusion surgeries were included. The primary outcomes of interest were the incidence of spinal non-union, PROMs and costs. Odds ratios (OR) were calculated for dichotomous variables and mean differences (MD) or standard mean differences (SMD) were calculated for continuous variables. Meta-analysis was performed using RevMan 5.4 software, with random effects applied in the presence of heterogeneity. Results: 34 studies (n = 433993) were included. Obesity (BMI ≥ 30) was significantly associated with a higher nonunion frequency (OR 2.10, 95%CI 1.23-3.60; p = 0.007). The ODI was significantly worse in the obesity group (MD 5.45, 95%CI 3.28 to 7.63). Pain measured by the VAS back pain and VAS leg pain scales, patients with obesity presented greater pain in the case of lumbar surgery: (MD 0.95, 95%CI 0.17 to 1.73) and (MD 0.94, 95%CI 0.68 to 1.20) respectively. The SF-36 PCS showed significantly worse outcomes in patients with obesity (MDS -0.46, 95%CI -0.82 to -0.09). Hospitalization costs were significantly higher in patients with obesity (MDS -0.09, 95%CI -0.12 to -0.07). Patients with obesity also had a significant increase in the cost per QALY (MDS -1.49, 95%CI -1.74 to -1.24). Conclusion: This meta-analysis suggests obesity is significantly associated with higher nonunion rates, poorer PROMs including ODI, VAS, and SF-36 scores, increased hospitalization costs and higher cost per QALY following spinal fusion, confirming obesity as a factor impairing surgical outcomes. Robert Oris 1 , Jonathan Dalton 1 , Omar Tarawneh 1 , Rajkishen Narayanan 1 , Gregory Toci 1 , Jarod Olson 1 , Rachel Huang 1 , Joydeep Baidya 1 , Chloe Herczeg 1 , Hannah Bash 1 , Dominic Finan 1 , Marco Goldberg 1 , Jose Canseco 1 , Alan Hilibrand 1 , Alex Vaccaro 1 , Gregory Schroeder 1 , Chris Kepler 1 , Mark Kurd 1 1 Rothman Orthopaedics, Philadelphia, United States Introduction: Disc herniation at the upper lumbar levels, including L1-L2 and L2-L3, is rare. The anatomy in this region is relatively more complex and constrained compared to lower lumbar levels, and a small number of studies have suggested that outcomes of upper-level microdiscectomy surgery may be inferior compared to lower-level microdiscectomy. Theoretically, performing a laminectomy at upper lumbar levels allows the avoidance of the technical challenges encountered during microdiscectomy due to anatomical constraints. However, it is not known whether outcomes are inferior following open decompression at upper lumbar levels when compared to microdiscectomy performed at lower lumbar levels. Therefore, the purpose of this study was to compare patient-reported outcomes following L1, L2, or L3 laminectomy versus L4-L5 or L5-S1 microdiscectomy. Methods: Patients who underwent a single-level lumbar laminectomy at L1, L2, or L3 or a microdiscectomy at L4-L5 or L5-S1 were identified. Only patients with at least 1 patient-reported outcome measure (PROM) completed at 1 year were included. Baseline demographic variables, including age, sex, BMI, diabetes status, and Charlson Comorbidity Index (CCI), were compared between groups. PROMs were compared between groups at 1 year postoperatively. A minimum clinically important difference (MCID) was defined according to previous literature as an improvement from baseline to 1-year of at least 14.9 for ODI, 4.7 for SF-12 MCS, 8.1 for SF-12 PCS, 2.1 for VAS back, and 2.8 for VAS leg. Multivariate logistic and linear regression analyses were performed to predict SF-12 PCS MCID achievement and 1-year VAS back scores, respectively, while controlling for confounding patient variables. Results: The final cohort included 252 patients who underwent lower lumbar microdiscectomy and 94 who underwent upper-level laminectomy. No significant differences between groups were present for sex or VAS leg. Patients undergoing upper lumbar laminectomy were older (64.0 ± 11.9 vs. 46.9 ± 13.5, p < 0.001), had higher average BMI (31.4 ± 6.08 vs. 28.4 ± 5.75, p < 0.001) and CCI (3.15 ± 1.78 vs 1.56 ± 1.33, p < 0.001), and were more likely to have diabetes (19.5% versus 7.69%, p = 0.017). Patients undergoing upper-level laminectomy were less likely to achieve MCID for SF-12 PCS (48.8% vs. 64.4, p = 0.041) and had higher VAS back scores at 1 year (3.58 ± 2.77 vs. 2.75 ± 2.54, p = 0.019). After controlling for age, diabetes status, BMI, and CCI, only BMI and CCI were independently predictive of not achieving SF-12 PCS MCID and having lower 1-year VAS back scores, respectively. Conclusion: Patients undergoing upper-level laminectomy had worse 1-year VAS back and SF-12 PCS scores compared to patients undergoing lower lumbar microdiscectomy. However, these differences were attributable to greater comorbidity burden and higher BMI based on multivariate analyses. Furthermore, VAS leg scores were not significantly different between groups. Surgeons can be assured that for the appropriately selected patient, patient-reported outcomes are similar when performing a laminectomy for upper lumbar disc herniation when compared to microdiscectomy for lower lumbar disc disease. Tien Nguyen 1,2 , Thanh Vo 1,3 , Tu Ngo 1,2 , Luc Nguyen 1,2 , Phong Pham 1,2 , Long Nguyen 1,2 1 Vietduc University Hospital, Spinal Surgery Department, Hanoi, Vietnam, 2 Vietnam National University, Spinal Surgery Department, Hanoi, Vietnam, 3 Hanoi Medical University, Surgery Department, Hanoi, Vietnam Introduction: The main objective of the study was to assess the effectiveness and safety of transforaminal percutaneous endoscopic discectomy (TPED) in relation to migrated lumbar disc herniation. Material and Methods: A retrospective study, focused on 32 patients (21 males, 11 females; mean age 46.72 ± 12.91 years) who underwent TPED for migratory lumbar disc herniation between January 2022 and January 2023 was conducted. The patients were divided into the four classes based on Lee’s classification. Through VAS, ODI, and MacNab criteria, the clinical results for the patients were followed up at discharge, 6 months, and 12 months post-operatively. Results: The average operation time was 83.44 ± 15.73 minutes, and the mean amount of blood lost was 84.06 ± 23.36 ml. The average hospital stay was 3.06 ± 1.41 days. Forty-six percents of patients had foraminoplasty, however, only far-downward (zone 4) ones needed 100% of it. After six months, 84.38% of the patients had favorable outcome as measured by MacNab criteria. VAS and ODI scores recorded significant improvement in all zones. There was registered a single case of transient abdominal compartment syndrome, but it was managed conservatively. Conclusion: TPED emerged as one of the favorable treatment options by achieving a high success rate simultaneously keeping postoperative complications at a low level. Nevertheless, patient, surgeon, and knowledge of all possible complications are some of the requirements in selecting the patient for the surgery. Hendrick Francois 1 , Esteban Quiceno Restrepo 2 , Isabelle Stockman 1 , Raphael Bastianon 2 , Alexander Aguirre 2 , Benard Okai 1 , Shashwat Shah 1 , Asham Khan 2 , Mohamed Soliman 2 , Jeffrey Mullin 2 , John Pollina 2 1 Jacobs School of Medicine and Biomedical Sciences, Buffalo, United States , 2 University at Buffalo Neurosurgery, Buffalo, United States Introduction: Lumbar spine fusion is one of the most commonly performed spinal surgeries, and investigating common complications such as adjacent segment disease (ASD) is a high priority. To the authors' knowledge, there are no previous studies investigating the utility of the preoperative magnetic resonance imaging-based fatty infiltration index of the paravertebral musculature in predicting radiographic and surgical ASD after lumbar spine fusion. We aimed to investigate the predictive factors for radiographic and surgical ASD, focusing on the predictive potential of the fatty infiltration of the psoas and multifidus muscles (psoas/multifidus index). Methods: A single-center retrospective analysis was conducted of all patients who underwent 1-3 level lumbar or lumbosacral interbody fusion for lumbar spine degenerative disease. Demographic data were collected, along with patient medical, and surgical data. Preoperative MRI was assessed in the included patients using the fatty infiltration of the psoas/multifidus index to identify whether radiographic ASD or surgical ASD could be predicted. Results: A total of 117 patients were identified (mean age, 59.8 ± 12.4 years; women, 54.0%). Twenty-three (19.7%) patients developed radiographic ASD, and 16 (13.9%) developed surgical ASD. A lower fatty infiltration index was a significant predictor of radiographic ASD in univariate analysis (0.2 ± 0.15 vs 0.7 ± 0.2; p < .001) and multivariate analysis (odds ratio, 1.501; 95% CI, 1.353-1.663; p < .001). For surgical ASD, a significantly lower index was seen in univariate analysis (0.15 ± 0.17 vs 0.6 ± 0.2; p < .001) and served as an independent risk factor in multivariate analysis (odds ratio, 1.509; 95% CI,1.324-1.720; p < .001). Conclusion: The fatty index of the psoas and multifidus muscle predicted the presence of ASD after lumbar fusions. Zuhair Mohammed 1 , Sean Taylor 1 , Saurabh Rawall 1 , Luke Hiatt 1 1 University of Alabama at Birmingham, Birmingham, United States Introduction: Interbody fusion is considered as the gold standard for preforming lumbar fusion. L5-S1 is a particularly challenging segment to achieve fusion as it is a junctional area and serves as a base for long fusions. Transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) are the commonest procedures to achieve L5-S1 fusion. The advantages of TLIF are that it allows a direct neural decompression and doesn’t need an additional anterior approach or access surgeon. However, TLIF has been shown to be inferior to ALIF with regards to maintenance of disc height as well as segmental and global lumbar lordosis. TLIF with expandable cage offers a potential technological advancement that could help in better radiographic alignment than a static cage. Previous work has shown improved disc height and lumbar lordosis with expandable cage TLIF over static cage TLIF. However, the utility of expandable cage TLIF at L5-S1 has not yet been reported specifically. Materials and Methods: 46 patients met the inclusion criteria of TLIF procedures at the lumbosacral junction between January 1, 2015 and September 1, 2023. Patients were retrospectively assigned between two cohorts, a static cage group and an expandable cage group. Radiographic data points included anterior and posterior disc heights, disc angle, L5-S1 sagittal lordotic angle, L4-S1 sagittal lordotic angle, L1-S1 sagittal lordotic angle, and lumbar distribution index. Radiographic data was measured and compared at three time points: preoperatively, at the first postoperative visit, and at the second postoperative visit. Results: 43 patients were included in our final analysis, with 28 receiving static cages and 15 receiving expandable cages. At the preoperative time point, expandable cages had a significantly higher posterior disc height (3.06 vs 5.03, p < 0.001). At the first follow up, the expandable cage had a significantly higher anterior disc height (11.80 vs 18.86, p < 0.001), posterior disc height (5.30 vs 7.80, p < 0.001), and disc angle (11.82 vs 16.27, p = 0.040). When examining changes from the preoperative to second follow up time points, the expandable cohort had a significantly larger change in anterior disc height (3.27 vs 9.22, p < 0.001), disc angle (0.24 vs 7.84, p = 0.002), L5-S1 sagittal lordotic angle (-0.37 vs 7.39, p = 0.043). Conclusion: Our findings indicate that for L5-S1 TLIF, expandable cages provide significantly greater correction with regards to anterior disc height, disc angle, L5-S1 sagittal lordotic angle, and L4-S1 sagittal lordotic angle as compared to static cages. Anthony Baumann 1 , Robjert Trager 2 , Omkar Anaspure 3 , Maria LaMontagne 4 , Gordon Preston 4 , Keegan Conry 4 , Jacob Hoffman 4 1 College of Medicine, Northeast Ohio Medical University, Rootstown, United States , 2 University Hospitals, Cleveland, Cleveland, United States , 3 Perelman School of Medicine, Philadelphia, United States , 4 Cleveland Clinic Akron General, Akron, United States Purpose: This study evaluates whether early postoperative physical therapy (PT) reduces the risk and quantity of opioid prescriptions and the development of opioid-related disorders within the first year after posterior lumbar interbody fusion (PLIF). Methods: We analyzed de-identified U.S. records (TriNetX, Inc.) of opioid-naïve adults with lumbar stenosis who underwent PLIF (2014-2023). Patients were grouped by PT received within two months post-surgery and propensity matched according to variables associated with opioid prescription. Outcomes included the risk ratio (RR) and mean number of opioid prescriptions, along with the incidence and RR of new opioid-related disorders in the first year. Results: After matching, there were 4,031 patients per cohort with adequately matched covariates. Compared to patients in the no postoperative PT cohort, in the first year after primary PLIF, patients in the postoperative PT cohort had a statistically significant lower risk of oral opioid prescription [95% CI] (62.6% versus 73.4%; RR: 0.85 [0.83,0.88]; p < 0.0001), a statistically significant lower mean count of oral opioid prescriptions (2.8 versus 3.7; p < 0.0001), and a statistically significant lower risk of a new diagnosis of an opioid-related disorder (0.72% versus 1.5%; RR: 0.49 [0.32,0.77]; p = 0.0013). Conclusion: Our findings support that postoperative PT after PLIF is associated with a lower risk and reduced number of opioid prescriptions, as well as a decreased risk of opioid-related disorders in the first postoperative year. These results should be validated by prospective trials that also explore the optimal timing of PT and its impact on opioid use and related disorders. Frederic Schils 1 , Renato Gondar 1 , Emmanuel Favreul 2 , Nacer Mansouri 3 , Aurélie Toquart 4 , Ibrahim Obeid 5 , Noel Graziani 6 1 Clinique Générale Beaulieu, Geneva, Switzerland , 2 Clinique Saint Charles, Lyon, France , 3 CHRU Nancy, France , 4 Polyclinique Majorelle 6, Nancy, France , 5 Clinique du dos de Terrefort, Bruges, France , 6 Hôpital Prive Clairval, Marseille, France Introduction: Transforaminal lumbar interbody fusion (TLIF) techniques are recognized as an efficient treatment for spondylolisthesis or degenerative disc disease in order to alleviate back and leg pain, improve function and provide stability to the spine. To achieve solid fusion and optimal clinical results, surgeons may choose among several implant characteristics like design, composition (i.e PEEK or Titanium) and biomechanical properties. Recently some authors advocated superior radiological results in terms of fusion or subsidence rates associated with the use of 3D printed Titanium cages. However there remains a lack of real-world evidence from prospective studies on safety and effectiveness of these new implant technologies with large, geographically diverse samples, involving multiple surgeons in different center. The purpose of this ambispective, multicenter, international, observational cohort study is to document clinical and radiological results over a two years follow-up period. Material and Methods: Eligible adult patients with lumbar degenerative disc disease or spondylolisthesis who underwent 1 or 2-level TLIF procedures with 3D printed Titanium Cages were enrolled from 6 sites in France and Switzerland. 187 patients reported outcome measures and were followed for clinical and radiological results and potential clinical and radiological complications during a 2 years post-op period. Patients were examined preoperatively, the day of discharge as well as after 2, 6, 12 and 24 months after surgery. Outcome parameters included intraoperative blood loss, duration of surgery, pre and post op pain (visual analog scale, VAS back and leg) disability (Oswestry Disability index, ODI) and patient’s satisfaction. Adverse event, device deficiency, radiological controls and concomitant medication were collected at all follow-up intervals. Results: The final cohort included 187 patients with a mean age of 61 years with a slight female preponderance (56%). Baseline demographic variable and comorbidity were collected as follow: Mean BMI 24, smokers (21%), obesity (23%), diabetes (10%), osteoporosis (8%), previous surgery (23%). Patient’s indication consisted of spondylolisthesis (80%), spinal stenosis (52%), instability (30%), herniated disc (15%), inflammation (10%) and retrolisthesis (3%). The mean operative time and blood loss volume were 116 min and 294 ml respectively. In total 5,1% serious adverse event were reported with 1,5% considered related to the procedure (dural tear, hematoma). Improvement of the ODI was substantial from 46,5% at baseline to 18% with a mean difference of 33%. Fusion was completed for 93% of patients at two years. Conclusion: When considering interbody material for TLIF, 3D printed Titanium cages performed well in terms of clinical and radiological results achieving high fusion rates with very low subsidence rates. Patients who underwent TLIF procedures with Titanium cages derived from this new 3D printed technology presented statistically significant and clinically meaningful improvements form baseline up to 24 months follow-up. The safety and efficiency of this type of implant seem to be promising as compared to standard PEEK or Titanium Coated PEEK cages with sustained advantage over a two years follow up period probably due to their superior bone integration and conductivity. The clinical relevance of these findings deserves further randomized, large scale prospective investigation. Yu-Cheng Yao 1 , Jing-Yang Liou 2 , Hsin-Yi Wang 2 , Po-Hsin Chou 1 , Shi-Tien Wang 1 1 Taipei Veterans General Hospital, Department of Orthopedics and Traumatology, Taipei, Taiwan , 2 Taipei Veterans General Hospital, Department of Anesthesiology, Taipei, Taiwan Introduction: Enhanced Recovery After Surgery (ERAS) protocol has been shown to accelerate patient recovery across various surgical fields, but is underexplored in lumbar spinal fusion. This study aimed to assess the impact of an ERAS protocol on perioperative outcomes in patients undergoing lumbar spinal fusion. Material and Methods: This is a prospective cohort study conducted at a tertiary medical center in Taipei, Taiwan, between November 2020 and May 2023. The study included 242 patients undergoing lumbar spinal fusion for degenerative spinal diseases, divided into ERAS and non-ERAS groups using propensity score matching (PSM). Main outcomes measured included operative duration, estimated blood loss (EBL), postoperative nausea and vomiting (PONV), analgesic use, and visual analog scale (VAS) pain score. Differences between the 2 groups were assessed using the 2-sample independent t-test or non-parametric Mann-Whitney U test for continuous variables, and the chi-square test or Fisher’s exact test for categorical variables. Results: The ERAS group had significantly shorter operative time (202 ± 68 min vs. 255 ± 85 min) and EBL (480 ± 302 ml vs. 641 ± 387 ml) compared to the non-ERAS group. The ERAS group had significantly less total morphine-sulfate-equivalent (MSE) consumption (27 ± 24 mg vs. 42 ± 42 mg) and used patient-controlled analgesia (PCA) (97% vs. 41%) more frequently compared to the non-ERAS group. Notably, the ERAS group had a shorter time to ambulation and shorter time to removal of Foley catheters. Conclusion: The ERAS protocol significantly enhances recovery trajectories and the quality of recovery in patients undergoing lumbar spinal fusion. Sahil Telang 1 , Nicole Hang 1 , Henry Avetisian 1 , Sagar Telang 1 , Andy Ton 2 , William Karakash 1 , Bahador Athari 1 , Jeffrey C. Wang 1 , Raymond Hah 1 , Ram Alluri 1 1 Keck School of Medicine of USC, Department of Orthpaedic Surgery, Los Angeles, United States , 2 University of California, Irvine , Department of Orthpaedic Surgery, Irvine, United States Introduction: Improved management of renal transplant patients has enhanced the feasibility and safety of surgical procedures in this population. However, there remains limited evidence describing the risk of lumbar fusion on patients with renal transplant. Our study’s purpose is to assess whether renal transplant patients are at higher risk of postoperative complications after primary lumbar fusion. We hypothesize that this patient population will experience higher rates of postoperative complications compared to non-transplant counterparts. Methods: Patients who underwent primary one- to three-level lumbar fusion for degenerative pathologies within the Pearldiver Mariner Database were queried from 2010 to Q3 of 2022 using Current Procedural Terminology (CPT) and ICD-9 and ICD-10 codes. Patients were further stratified on the basis of prior renal transplantation, and patients with history of failed transplant or indications for malignancy, infection, or trauma were excluded. Propensity matching based on age, sex, Elixhauser Comorbidity Index (ECI), smoking, and osteoporosis was performed to create 1:1 cohorts of renal transplant patients and non-transplant counterparts. Complication and readmission rates were analyzed using conditional logistic regression analysis. Results: Overall , 411,834 lumbar fusion patients were identified of which 508 (0.12%) had undergone prior renal transplantation. Logistic regression analysis revealed increased risk of acute kidney injury (AKI) (OR:1.992, 95%-CI: 1.381-2.788, p < 0.001) and urinary tract infection (UTI) (OR:1.794, 95%-CI: 1.229-2.530, p < 0.05) amongst renal transplant patients. Notably, risk of one- and five-year revision, 30-day surgery site infection, and 30-day readmission were comparable between groups. Conclusion: Renal transplant status confers increased risks of postoperative UTI and AKI, while demonstrating marginal impact on other perioperative complications as well as revision and readmission rates in patients undergoing one- to three-level lumbar fusion for degenerative pathologies. While perioperative strategies should center on mitigating the risk for UTI and AKI, primary lumbar fusion is nonetheless a viable surgical option for renal transplant patients without any appreciable differences in clinical outcomes. Sathish Muthu 1,2,3 , Simister Samuel 4 , Hania Shazad 4 , Hai Le 4 , Luca Ambrosio 5 , Stipe Corluka 6 , Gianluca Vadalá 5 , Patrick Hsieh 7 , Michael Virk 8 , S. Tim Yoon 9 , Samuel Cho 10 1 Government Medical College & Hospital, Department of Orthopaedic Surgery, Karur, India , 2 Karpagam Academy of Higher Education, Department of Biotechnology, Coimbatore, India , 3 Orthopaedic Research Group, Department of Spine Surgery, Coimbatore, India , 4 UC Davis Medical Center, Department of Orthopaedics, California, United States , 5 Università Campus Bio-Medico di Roma, Reaserch Unit of Orthopaedic and Trauma Surgery, Rome, Italy , 6 University Hospital Centre Sestre Milosrdnice, Spinal Surgery Division, Department of Traumatology, Zagreb, Croatia , 7 Keck School of Medicine, Department of Neurological Surgery and Orthopaedics, Los Angeles, United States , 8 Weill Cornell Graduate School of Medical Sciences, Department of Spine Surgery, New York, United States , 9 Emory University, Department of Orthopaedics, Atlanta, United States , 10 Icahn School of Medicine at Mount Sinai, Department of Orthopaedic Surgery, New York, United States Introduction: The literature remains controversial about the treatment choice in the management of Grade I L4-5 degenerative lumbar spondylolisthesis (DLS). The commonly employed treatment method includes decompression without or without fusion at the involved level. The addition of fusion to the decompression surgery remains largely subjective in the hands of surgeons based on various patient-and surgeon-related factors. We explore the demographic factors amongst surgeons responsible for decision-making in the management of Grade I L4-5 DLS. Methods: A survey presenting three clinical scenarios of DLS with varying degrees of neurological compression and instability was distributed to the AOSpine members globally to ascertain surgical management preferences. Management options such as decompression only or decompression and fusion and the techniques that would be employed were presented to the responders. Results: After dissemination, 479 surgeons responded to the survey. Direct decompression was preferred for all three scenarios with and without neurologic deficits (82.5, 81.2, and 56.8%), with the majority favouring open procedures over minimally invasive or endoscopic procedures. Notably, younger, less experienced, and fellowship-trained surgeons showed a higher inclination toward minimally invasive and indirect decompression methods. A strong preference for surgical fusion over decompression (75.2, 92.5 and 86.6%, respectively) was also significantly observed, reflecting a consensus on the need to achieve segmental stability. Conclusion: The results of this study demonstrate a pronounced preference for direct decompression and fusion among a group of global surgeons when treating L4-5 Grade I DLS across all demographics. This indicates a consensus on achieving decompression and stability; however, there are some trends indicating the impact of surgical management based on age, experience, and training of the treating providers. These findings suggest an evolution of surgical interventions toward less invasive techniques, particularly among younger surgeons, highlighting the need for global education to adopt innovative approaches in the management of DLS. Jonathan Dalton 1 , Chloe Herczeg 1 , Rajkishen Narayanan 1 , Alec Giakas 1 , Robert Oris 1 , Rachel Huang 1 , Joydeep Baidya 1 , Jarod Olson 1 , Jose Canseco 1 , Alex Vaccaro 1 , Alan Hilibrand 1 , Gregory Schroeder 1 , Chris Kepler 1 , John Mangan 1 1 Rothman Orthopaedic Institute, Philadelphia, United States Introduction: Recent research has associated depression with worse patient reported outcomes both pre- and postoperatively, and with adverse events after lumbar fusion. However, existing literature rarely utilizes a clinical diagnosis of depression, but rather infers from short-form, preoperative mental health screening surveys. This is problematic because these scores are dynamic - poor preoperative mental health scores can substantially improve after surgery. Additionally, spine surgery itself is a risk factor for de novo depression. The concept of “depressive burden” has been used in a small number of studies to describe patients who score poorly on psychometric evaluations both pre- and postoperatively. However, there is a paucity of literature examining this concept in the setting of lumbar fusion. Material and Methods: Patients who underwent elective lumbar fusion (2017-2022) were reviewed for demographic, surgical, perioperative, and patient reported outcome measure (PROM) data. PROMs included Oswestry Disability Index (ODI), Visual Analog Scale (VAS) Back and Leg, SF-12 Mental Component (MCS), and Physical Component Score (PCS). Each patient’s preoperative and 3-month postoperative MCS were averaged together - patients in the lowest tercile of averages were considered to have high “depressive burden”. PROM and Minimal Clinically Important Difference (MCID) values were compared between patients with versus without high depressive burden. Appropriate statistical analysis was performed. Alpha was set at 0.05. Results: Amongst the entire cohort, 127 (32.9%) had high depressive burden, while 258 (67.1%) did not. Both groups had similar demographics, indications, and surgical type/complexity. Patients with high depressive burden had worse PROMs for all metrics at 6-month and 1-year follow-ups with all p values < 0.001. High depressive burden patients had similar change in PROMs from preoperative to 3 months, but had more improvement in MCS, and less improvement in PCS at 6 months and 1 year postoperatively. High depressive burden patients were less likely to achieve MCID for ODI (p = 0.022), VAS Leg (p = 0.025), and PCS (p = 0.001) at 1 year, while these patients were more likely to achieve MCID for MCS (p = 0.033). Conclusion: High depressive burden in the setting of lumbar fusion was associated with worse performance on multiple PROM scores at all time points postoperatively, and a decreased likelihood of achieving MCID. Beyond six months postoperatively, patients with high depressive burden began to accrue relatively more improvement in MCS scores, but relatively less improvement on PCS scores. This emphasizes the dynamic nature of a patient’s performance on mental health scoring metrics, and underscores the importance of identifying patients who have high depressive burden throughout the perioperative period. Further research should aim to address ways to optimize outcomes for this vulnerable population undergoing lumbar fusion. Diana Chávez 1 , Pedro Chavira Ramos 1 , Alberto Perez 1 1 Hospitales Angeles, Neurosurgery, Mexico, Mexico Study Design: Systematic review, expert consensus. Objective: The design of a new classification method by collecting higher and lower criteria, to determine the presence of instability in degenerative disease. Material and Methods: From a total of 60 studies that were included in our systematic review to identify factors associated with degenerative spinal instability, we considered major criteria (axial angulation more than 10 degrees, displacement greater than 3 mm, vacuum phenomenon, axial pain), and minor criteria (high pelvic incidence > 50 degrees, displacement between 1-3 mm, angulation between 5 - 10 degrees, synovial cyst, modic changes type I and II, facet hydratrosis greater than 1 mm), classifying as unstable or stable depending on whether there were 2 major criteria present or 1 major criterion with 2 minor ones. Results: Patients with instability criteria meet 360 fusion criteria, while patients without instability criteria are candidates for conservative treatment or total disc replacement surgery. Conclusion: ST SCORE is a useful, valid, and reproducible tool for decision making in patients with degenerative lumbar disease. The presence of major criteria can be used as a guide for 360 arthrodesis treatment in patients. Maura da Silva Cambango 1 , Renato Pereira 1 , Pedro Ribeiro 1 , Leandro Oliveira 1 1 Braga Local Health Unit (Braga Hospital), Neurosurgery, Braga, Portugal Introduction: Spontaneous pneumorrachis is a rare condition, that consists of the presence of air in the sub- and/or epidural cavity. It is most commonly associated with trauma or complications from invasive procedures. Generally, the etiology of spontaneous pneumorrachis is unknown, although some authors argue that it is associated with spinal degenerative pathology, namely empty disc syndrome. Material and Methods: We review the literature and describe a clinical case with lumbar pain and radicular complaints; Lumbar CT scans and lumbar MRI revealed endocanalar (epidural) air at the level of L4-L5. Results: In an initial phase, a conservative approach was chosen, followed by a percutaneous approach (CT-guided lumbar puncture), with transient improvement of the condition, having recurred, clinical and imaging several times. After multidisciplinary discussion, formal surgery was performed, which has been effective so far. Conclusion: The present case, in addition to its rarity, aims to demonstrate the efficacy and safety of the formal surgical approach to resolve similar situations. Gonzalo Mariscal 1 , Praveer Vyas 2 , Chris Arts 3 , Thomay Hoelen 3 1 Institute for Research on Musculoskeletal Disorders, Valencia Catholic University, Valencia, Spain , 2 UPMC Presbyterian Hospital, Pittsburgh, United States , 3 Maastricht University Medical Centre, Maastricht, Netherlands Introduction: The choice of the implant material is important for spinal fusion. While titanium demonstrates osteointegration, PEEK allows for radiographic monitoring. TiPEEK combines these advantages, but comparative evidence is limited. To compare the fusion rates, functional outcomes, and complications between TiPEEK and PEEK cages a systematic review and meta-analysis of comparative studies was performed. Materials and Methods: Four databases were systematically searched according to PRISMA. Adult patients who underwent one- or two-level lumbar fusion with TiPEEK or PEEK cages were included in the study. Studies that reported radiographic fusion and functional or complication outcomes were also included. Study quality was assessed using the Cochrane Risk of Bias tool and MINORS criteria. The meta-analysis was performed using Review Manager 5.4. Heterogeneity was assessed using I2, and random effects were used to analyze the heterogeneity. Results: Eight studies (n = 670) were analyzed. TiPEEK showed a significantly higher overall fusion rate (OR 1.83, 95%CI 1.18-2.83). TiPEEK cages presented significantly higher fusion rates at 6 months (OR 2.52, 95% CI 1.11 to 5.72), but there were no significant differences at 12 months (OR 1.33, 95% CI 0.65 to 2.73). No differences were observed in the global ODI (SMD -0.04, 95%CI -0.15-0.06). There were no significant differences regarding overall subsidence (OR 0.72, 95% CI 0.48 to 1.07), screw complications (OR 1.25, 95%CI 0.30-5.27) or reoperations (OR 0.61, 95%CI 0.11-3.37). Conclusion: TiPEEK cages demonstrated an improved overall fusion rate compared to PEEK, particularly in the short term. However, the functional outcomes and safety profiles were comparable. Pranit Kumaran 1 , David McCavitt 1 , Zachary Singh 1 , Henry Avetisian 1 , William Karakash 1 , Jeffrey C. Wang 1 , Raymond Hah 1 , Ram Alluri 1 1 Keck School of Medicine of USC, Department of Orthopaedic Surgery, Los Angeles, United States Introduction: Endoscopic decompression (ED) and microscopic decompression (MD) represent advancements in the surgical treatment of radicular low back pain. However, systematic reviews and meta-analyses of these novel techniques may be susceptible to a form of bias known as “spin”, due to the limited availability of high quality, large scale randomized controlled trials. This study aims to identify and characterize the incidence of spin in the abstracts of systematic reviews and meta-analyses comparing ED to MD in the treatment of degenerative lumbar stenosis. Additionally, this study evaluates the quality of these reviews using the AMSTAR 2 criteria, and investigates any patterns between spin incidence and study characteristics, such as journal of publication, level of evidence (LOE), funding, Clarivate Impact Factor, or ScopusCiteScore. Materials and Methods: The study followed the Preferred Reporting Items for Systematic reviews and meta-analysis (PRISMA) guidelines. Articles comparing ED and MD were collected from PubMed, Scopus, and Web of Science databases. Screening and data extraction were conducted independently by two authors. Extracted data included study title, publication year, journal, LOE, study design, funding source, adherence to PRISMA guidelines, preregistration of the study protocol, and primary and secondary outcome measures for each article. Abstracts were graded in binary fashion (“0” or “1”) for each of the 15 most common types of spin. Full texts were graded according to the AMSTAR 2 criteria, with quality categorized into “high”, “moderate”, “low” or “critically low”. Results: The literature search yielded 1546 articles, with 696 removed as duplicates. Ten articles met inclusion criteria and were included in our analysis. All included studies were found to have at least one type of spin, with a mean occurrence of 2.9 (range: 1-5). The most common spin types were types 12 (“Conclusion claims equivalence or comparable effectiveness for non statistically significant results with a wide confidence interval”) and type 3 (“Selective reporting of or overemphasis on efficacy outcomes or analysis favoring the beneficial effect of the experimental intervention”), each present in 5/10 (50%) of the included studies. All studies received a “critically low” confidence rating on the AMSTAR 2 scale. Statistical analysis revealed no significant associations between incidence of spin type with year of publication, journal of publication, number of citations, LOE, funding, Clarivate Impact Factor, or ScopusCiteScore. Conclusion: Although no significant associations were found between spin and article characteristics, spin was prevalent in abstracts comparing ED and MD, and all full texts were rated as low quality grades based on AMSTAR 2 criteria. The AMSTAR analysis highlighted poor adherence to criteria related to the study selection process, underscoring the need for more rigorous systematic reviews in this area. Marcelo Molina 1,2 , Sebastian Vial 3 1 Instituto Traumatológico, Cirugía Ortopédica, Santiago, Chile , 2 Clinica Alemana, Traumatología, Santiago, Chile , 3 Instituto Traumatológico, Ortopedia, Santiago, Chile Introduction: Radiological classifications are important for establishing a common language and improving communication among medical professionals when discussing pathologies, defining severity, prognosis, and treatment options. The purpose of this study is to conduct a systematic literature review of classifications for degenerative pathologies of the lumbar spine. The objective is to perform a thorough review of available classifications for lumbar spinal degenerative diseases. Methods: We performed a systematic literature review search for papers that proposed or described radiological classification systems for degenerative lumbar spine disease, such as lumbar disc herniation, facet joint arthritis, spondylolisthesis, and lumbar stenosis. The literatura was performed in MEDLINE and EMBASE, limited to English articles published from 1980 to the present. The reliability tests of the reviewed articles were assessed with the “Intraclass Correlation Coefficients” (ICC) and “Cohen's Kappa coefficient” (k). Results: We found 1873 articles. A total of 64 articles were reviewed, identifying 31 radiological classification systems. We found 7 classifications for degenerative disc disease, 7 for disc herniation, 7 for facet joint osteoarthritis, 8 for degenerative spinal stenosis, and 2 for degenerative spondylolisthesis. Of the 31 systems found, 24 had interrater agreement studies. The clinical orientation of the classification was analyzed when appropriate. Conclusions: Reliability studies play a crucial role in evaluating a classification system as they enable reproducibility among evaluators, thereby fortifying the system. Classifications should not only be endorsed based on their validation and reliability studies, but it is also crucial to assess their feasibility for practical implementation in clinical settings. A classification system should have a reliability with Kappa or ICC over 0.60 to be recommended. It should provide a clinical orientation to make therapeutic decisions and form part of a guideline. Continued research on classification development is essential to improve systems, enhancing their clinical utility and bolstering their reliability. Stevin Lu 1 , Jonathan Ochoa 2 , Hania Shazad 2 , Ian Marquez 2 , Kanwar Parhar 3 , Rolando Roberto 2 , Yashar Javidan 2 , Hai Le 2 1 Creighton School of Medicine, Omaha, United States, 2 UC Davis Medical Center, Sacramento, United States, 3 Washington State University Elson S. Floyd College of Medicine, Spokane, United States Introduction: Preoperative urinalysis (UA) is commonly performed for risk stratification of patients undergoing elective lumbar spine fusion surgery. However, the benefits of routine preoperative UA remain unclear and may contribute to increased hospital costs and unnecessary antibiotic treatment. This study assesses the utility of routine preoperative UA as a predictor of postoperative complications following elective lumbar spine fusion surgery. Material and Methods: Patients aged ≥ 18 years undergoing elective lumbar or lumbosacral fusion surgery for degenerative pathology from 2018 to 2022 at a single academic institution were included. Patients undergoing surgery for trauma, tumor, and/or deformity were excluded. Patients were classified into 3 groups: No Urinalysis (No-UA), Negative Urinalysis (Negative-UA), and Positive Urinalysis (Positive-UA). A retrospective review of medical records was conducted including patient characteristics, rates of interventions due to urinalysis, and rates of postoperative infections and wound dehiscence. Postoperative complications were categorized into 6 groups: urinary tract infection (UTI), pneumonia, bacteremia, deep wound infection, superficial wound infection, or wound dehiscence. Emergency department encounters and return to the operating room within 3-months postoperatively were recorded. ANOVA and chi-square models were used to assess for significant differences (p < 0.05). Results: 492 patients met the inclusion criteria: 53 No-UA, 333 Negative-UA, and 107 Positive-UA. Average age of patients was 65.3 years and 267 (54.3%) were male. In patients with a positive urinalysis, 18 (16.8%) of them returned a positive urine culture. Patients in the positive-UA group (N = 21; 19.6%) were significantly more likely to receive preoperative antibiotics than patients in the No-UA (N = 1; 1.9%) and Negative-UA (N = 0; 0%) groups (p < 0.05). Patients with a positive-UA (N = 23, 21.5%) also presented with higher rates of postoperative UTIs than patients in the No-UA (N = 2; 3.8%) and Negative-UA (N = 17; 5.1%) groups (p 0.05). There were also no significant differences in return to OR, return to ED, reinsertion of foley catheters, duration of indwelling catheterization, and hospital length of stay (p > 0.05). Among patients with postoperative UTIs, univariate analysis indicated that female sex, positive preoperative UA, older age, higher American Society of Anesthesiologists score, greater Oswestry Disability Index, and longer hospital length of stay were associated with increased risk of infections (p < 0.05). However, after generating a multivariate analysis to adjust for confounding effects, only positive preoperative urinalysis remained significant (p = 0.002). Conclusion: This study suggests there may be a limited role in performing routine preoperative urinalysis prior to elective lumbar spine fusion procedures. Patients with a positive preoperative urinalysis had higher rates of postoperative UTIs; however, no significant differences were seen for other types of infection, wound dehiscence, return to OR, and return to ED. Amongst patients in the positive-UA group that returned to the OR for surgical site infections, only one patient had an intraoperative wound culture that matched the preoperative urine culture. This study may help further improve preoperative assessment guidelines and assist with patient counseling and considerations prior to elective lumbar fusion surgery. Wyatt Vander Voort 1 , Stevin Lu 2 , Hania Shazad 1 , Aliyah Walker 1 , Gregory Harbison 1 , Yashar Javidan 1 , Rolando Roberto 1 , Eric Klineberg 1 , Hai Le 1 1 UC Davis Medical Center, Sacramento, United States, 2 Creighton School of Medicine, Omaha, United States Introduction: Emergency department (ED) utilization and readmission to the hospital after lumbar fusion surgery is common. These encounters are associated with long wait times, low patient satisfaction, and are an under-recognized source of healthcare costs. The purpose of this study is to identify patient and surgical risk factors for ED utilization and readmission to the hospital following elective lumbar fusion surgery. Material and Methods: Patients aged ≥ 18 years undergoing elective lumbar or lumbosacral fusion surgery for degenerative pathology from 2018 to 2022 at a single academic institution were included. Patients undergoing surgery for trauma, tumor, and/or deformity were excluded. A retrospective review of medical records was conducted. Patient and surgical characteristics and preoperative patient reported outcomes (PRO) scores including Oswestry Disability Index (ODI), 12-Item Short Form Survey (SF-12), Charlson Comorbidity Index (CCI), and Patient-Reported Outcomes Measurement Information System Computer Adaptive Testing (PROMIS/CAT) were obtained. ED visits or readmission within 3 months postoperatively were recorded. Univariate and multivariate regression models and chi-square tests were used to identify factors associated with ED presentation. Results: 495 patients were included. 268 (54.1%) were male. Average age was 65.3 ± 11.2 years. Average CCI was 3.4 ± 2.0. Average number of levels fused was 2.0 ± 1.0. 59 patients (11.9%) had fusion to the pelvis. 93 patients (18.7%) returned to the ED and 74 patients (14.9%) were readmitted to the hospital within 3 months after their operation. For each one-unit increase in ODI, the odds of returning to the emergency department increased by 3.6% (p = 0.09). For each one-unit increase in PROMIS/CAT Depression Subscale, the odds of returning to the emergency department increased by 4.1% (p = 0.06). For patients who have fusion to the pelvis, the odds of returning to the emergency department is increased by 111.7% (p = 0.06). For each additional day stay in the hospital, the odds of returning to the emergency department increased by 8.3% (p = 0.08). Patients who had higher preoperative CCI scores (4.6 ± 2.5 vs. 3.1 ± 1.9) and longer hospital length of stay (4.1 ± 1.9 vs. 3.5 ± 2.5 days) were significantly more likely to be readmitted (p < 0.01). Conclusion: ED utilization and readmission to the hospital following elective spine surgery is an under-recognized source of healthcare costs, leading to patient dissatisfaction. This study demonstrated increased odds of ED utilization and readmission in patients with poorer preoperative PRO scores, higher CCI, and longer hospital length of stay. This information may assist in patient counseling, selection, and optimization prior to elective lumbar spine surgery. Juan Lourido 1 1 TreeTop Hospital, Neurosurgery, Hulhumale, Maldives The use of interspinous devices (ISD), often referred to as interspinous distraction spacers (IDS), interspinous distraction devices (IDD) or interspinous process decompression (IPD) systems, increased sharply at the turn of the century, in context of a raised theoretical interest on posterior dynamic stabilization (PDS) of the spine. In spite of some randomized studies supporting its utility in restricted indications, its use has been discarded by most spinal institutions, and production stopped by leading industry actors. Paradoxically, it is noted a disproportionate lack of quality outcome publications, compared to the popularity and large numbers used on patients in the past. We present a consecutive series of 241 patients (unselected, no rejections), operated between 2009 and 2012, marked for surgery by a spinal surgeon different from the operating surgeon. This subset is part of a larger cohort of 657 consecutive patients referred from a waiting list. Criteria at the time for decision to enhance the surgery with ISD were: “Use to keep the neural spaces open / Use as optional tool, discuss with patient / Use as complement to decompression surgery” 241 patients underwent surgery. 6 different types of ISD. 3 patients were operated at L5/S1 level. No short term reoperations (1year). All patients had a hospital stay of 24h. We present the reoperation rate in the long term (13-16years) in this series and discuss about the utility and problems of such systems. Marcelo Molina 1,2,3 , Alfredo Guiroy 4 , Jose Dangond 5 , Gonzalo Kido 6 , Michael Dittmar 7 , Lucio Gonzales 8 , Cristobal Carvajal 3 1 Clínica Alemana, Traumatología, Santiago, Chile , 2 Instituto Traumatológico, Traumatología y Ortopedia, Santiago, Chile , 3 Universidad Finis Terrae, Santiago, Chile , 4 Clinica de Cuyo, Neurocirugía, Mendoza, Argentina , 5 Fundación Clinica Campbell, Ortopedia, Bogota, Colombia , 6 Hospital Italiano , Ortopedia, Buenos Aires, Argentina , 7 Universidad de Guadalajara, Ortopedia, Guadalajara, Mexico , 8 Instituto Traumatológico, Ortopedia, Santiago, Chile Introduction: Depression is an important factor to consider when evaluating a patient with lumbar degenerative stenosis (LDS). Some studies suggest that depression is a poor prognostic factor after surgery, while others propose improvement of depressive symptoms with surgery. The aim of this study is to assess the impact of spine surgery on patients with LDS and its correlation with Depression and quality of life questionnaire scores. Methods: This is an analytical, prospective, multicenter study. It involves demographic and diagnostic evaluations, including the PHQ-9 questionnaire (for depression) and the Oswestry Disability Index (ODI) for low back pain disability. It includes patients with LDS who were treated with and without surgery from 7 hospitals in Latin America (Chile, Argentina, Colombia, and Mexico). The RedCap Database of the Lumbar Spine Stenosis project (ESTENOCOL) was utilized. Statistical analysis involved the chi-square test with p < 0.05. The follow-up period was 2 years. Results: The study included 243 patients, with 136 who underwent surgery and 107 managed conservatively with LDS. 51% were men, with an average age of 61 years. There were 4 patients diagnosed with depression (1.6%). The PHQ-9 scores and ODI of the conservative group at admission, 1 year, and 2 years of follow-up were: 8.0-31; 8.1-35; 7.6-48, respectively. The PHQ-9 and ODI scores of the surgical group at admission, 1 year, and 2 years post-operatively were: 10.0-48.3; 2.6-11.4; 4.4-18.0. Only 1.6% had a diagnosis of depression upon admission. At admission, PHQ-9 scores were in the range of mild depression in conservative group and moderate in surgical group, with worse ODI in surgical group (p < 0.05). At the 2-year follow-up in the conservative group the PHQ9 and ODI did not show significant changes compared to admission (p = 0.3). Conclusion: The surgical group showed a significant improvement in the PHQ-9 and ODI at 1 and 2 years post-operatively compared to admission and also compared to conservative group (p < 0.05). This study suggests that the diagnosis of depression is underestimated. Surgery for LDS significantly improves depressive symptoms and disability due to low back pain compared to conservative management. Marcelo Molina 1,2,3 , Gonzalo Kido 4 , Alfredo Guiroy 5 , Jose Dangond 6 , Michael Dittmar 7 , Lucio Gonzales 8 , Cristobal Carvajal 3 1 Clínica Alemana, Traumatología y Ortopedia, Santiago, Chile , 2 Instituto Traumatológico, Traumatología y Ortopedia, Santiago, Chile , 3 Universidad Finis Terrae, Santiago, Chile , 4 Hospital Italiano, Ortopedia, Buenos Aires, Argentina , 5 Clínica de Cuyo, Neurocirugía, Mendoza, Argentina , 6 Fundación Clínica Campbell, Ortopedia, Barranquilla, Colombia , 7 Universidad de Guadalajara, Ortopedia, Guadalajara, Mexico , 8 Instituto Traumatológico, Ortopedia, Santiago, Chile Introduction: Degenerative lumbar stenosis (DLS) has various treatment options and different functional prognoses. Currently, there is no agreement on the clinical or imaging factors that can predict the prognosis or define the treatment of patients with DLS. The objective is to identify factors associated with a poor functional prognosis, defined as an Oswestry Disability Index (ODI) score greater than 30 after 1 year of follow-up, and to determine factors associated with treatment decisions for patients with DLS. Materials and Methods: This is a multicenter, prospective, and analytical study of patients with DLS from seven hospitals in Latin America since April 2021, with a minimum follow-up period of 1 year. The study analyzed 26 clinical variables, 42 imaging measurements (including radiographs and MRI), and 4 questionnaires (ODI, SF36, Zurich, and PHQ9) using multivariate logistic regression. The analysis aimed to identify factors predictive of ODI > 30 at 1 year and the type of treatment indicated: conservative group (CG) and surgical group (SG). The study compared the ratio of ODI > 30 per year and the “Delta ODI” (ODI at 1 year - ODI at entry) between CG and SG. The RedCap database of the ESTENOCOL (Lumbar Spinal Stenosis) study was used for the analysis. Results: The study included 119 patients, with 35 patients in the CG and 84 patients in the SG. A higher probability of ODI > 30 per year was associated with the conservative treatment (p = 0.001; OR = 40.091), spinal instability, ODI > 30 at admission, and older age. The indication for surgery was associated with low back pain (p = 0.039; OR = 29.8) and herniated disc. In contrast, a higher Body Mass Index (BMI), Modic type II changes, and hyperkyphosis T2T12 were related to the conservative group. The ODI > 30 at one year was 54% in the conservative group and 7% in the surgical group (p < 0.001; OR = 15.4). The “Delta ODI” was -6 in the conservative group and -35 in the surgical group (p 30 on admission, and instability were associated with worse functional outcomes in patients with DLS. Additionally, significant improvement in pain disability was observed with surgery based on delta ODI. Marcelo Molina 1 , Lorena Salvo 2 , Constanza Arriola 3 1 Instituto Traumatológico, Traumatología y Ortopedia, Santiago, Chile , 2 Instituto Traumatológico, Statistics Department GRD, Santiago, Chile , 3 Instituto Traumatológico, Statistics Department, Santiago, Chile Introduction: Degenerative Lumbar spinal stenosis (DLSS) is the most common cause of spine surgery for patients above 55 years. Surgery options include decompression alone or with spinal fusion. The DRG system uses classification algorithms that categorize patients into groups with similar clinical and resource consumption characteristics, using ICD-10 nomenclature for diagnoses and ICD-9-CM for procedures. The objective is to Identify clinical and epidemiological variables of DLSS surgery patients based on Chile’s DRG system data and define factors associated with arthrodesis as a complement to decompression. The study design is a retrospective observational study. Methods: This study used the national DRG database to analyze factors predicting the need for fusion in patients with DLSS. Data from 31 public hospitals in Chile were analyzed for patients discharged between 2020 and 2022. Variables considered included age, gender, presence of other spinal pathologies, and attending physician specialty. For the descriptive analysis of qualitative variables, frequencies and percentages were used. The study used univariate and multivariate logistic regression analysis. A statistical significance level of less than 0.05 was considered. Results: We analyzed 1024 patients with lumbar spinal stenosis and found that 54.6% were female and 45.4% were male (p= 0.0034). The majority of the patients (57.4%) were aged between 60 and 79 years. 75% of orthopedic surgeons opted for decompression plus arthrodesis, while neurosurgeons preferred decompression alone in 73% of cases. The most significant predictors for decompression with fusion were the physician’s specialty in orthopedic surgery, female sex, and the presence of other spinal pathologies such as scoliosis, herniated disc, and spondylolisthesis. Patients treated by an Orthopedic Surgeon had an 8.2 times greater probability of undergoing decompression plus arthrodesis as compared to those treated by a Neurosurgeon. Additionally, the presence of spondylolisthesis increased the probability of decompression with fusion by 6.2 times, and the presence of scoliosis increased it by 6.6 times. Neurosurgeons opted for decompression alone in 89.7% of the cases with DLSS stenosis and herniated disc, while only 48.9% of orthopedic surgeons opted for the same option (p = 0.0000). Conclusion: Our study based on DRG records from public hospitals in Chile has identified certain factors linked to a higher frequency of spinal arthrodesis. These factors include the surgery being performed by orthopedic surgeons, patients aged between 40 and 60 years old, the presence of degenerative spondylolisthesis and degenerative scoliosis, and the absence of a herniated disc. Marcelo Molina 1,2 , Ramón Torres 3 , Lucio gonzales 3 , Carlos Cortes 3 , Lorena Salvo 3 1 Instituto Traumatológico , Ortopedia y Traumatología, Santiago, Chile , 2 Clínica Alemana, Ortopedia y Traumatología, Santiago, Chile , 3 Instituto Traumatológico, Ortopedia y Traumatología, Santiago, Chile Introduction: Full endoscopic (FE) lumbar discectomy has shown similar clinical results and safety compared to the microsurgical technique in treating Lumbar Disc Herniation (LDH). The objective of this study is to analyze the clinical, functional results, and complications in patients who underwent FE lumbar discectomy for LDH. Method: This is was a prospective, descriptive, and analytical study of patients who underwent FE lumbar discectomy for LDH between 2021 and 2024. The study recorded epidemiological and surgical parameters, as well as intraoperative and postoperative complications. Pain levels were measured using the Visual Analogue Scale (VAS) for lumbar and radicular pain. Also patients were assessed with Oswestry Disability Index (ODI), SF36, and PHQ9 (Depression) preoperatively and at 1, 3, 6, and 12 months postoperatively. The study compared outcomes between the transforaminal (TF) and interlaminar (IL) techniques, preoperative pain duration (less or more than 12 months), primary and recurrence LDH, and obese and non-obese patients. Results: The study included 68 patients, of which 52% were men, with a median age of 45 years. 50% of the patients had LDH at L4-L5 level and 42% at L5-S1 level. The results showed that patients significantly improved in ODI, SF36, PHQ9, and pain levels at 1 year compared to baseline (p < 0.05). Primary LDH patients showed better ODI and SF36 scores at 1 month postoperatively (p < 0.05). Non-obese patients presented better radicular VAS, PHQ9, and SF36 scores at 1 year post-surgery (p < 0.05). There were no significant differences based on the duration of preoperative pain. The study also found differences in surgical time, with less time required for the TF technique compared to the IL technique (75 vs. 99 minutes, p < 0.05). The study reported 21 complications, including 4 intraoperative and 17 postoperative complications (such as 7 dysesthesias and 5 recurrences), leading to 7 re-operations. The study also found a higher complication rate in patients undergoing TF technique (p < 0.05). Conclusion: The study presents the experience of patients who underwent FE lumbar discectomy. It observed clinical and functional improvements, with some differences between patient groups. Patients operated with FE technique showed improvement in pain, SF36, ODI, and PHQ9 at one year compared to baseline. The study also noted better results in non-obese and primary with LDH. Additionally, it found shorter surgical time and a higher complication rate associated with the TF technique. Bruno Braga Roberto 1 , Michel Kanas 1 , Guilherme Pajanoti 1 , Delio E. Martins 1 , Alberto Gotfryd 1 , Marcelo Wajchenberg 1 , Nelson Astur 1 1 Hospital Israelita Albert Einstein, Sao Paulo, Brazil Introduction: The most common degenerative lumbar spine conditions involve the degeneration of the intervertebral disc, facet joints, capsule, and vertebral ligaments, which leads to diseases such as disc herniation, spondylolisthesis and canal stenosis. Although degenerative conditions are part of the natural progression of aging, it is suspected that in the spine these are related to the load that the vertebrae bear over time. In 2005, Roussouly et al., created a classification that addresses the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the orthostatic position in order to quantify and classify common variations in the sagittal alignment of the spine, the sacrum, and the pelvis. While developing their classification, Roussouly et al., observed that the types of lordosis could be related to some of the most common degenerative lumbar spine diseases, suggesting that patients with symptomatic disc herniation fit into types 1 and 2 while stenoses were most often seen in cases classified as type 4. Patients classified as type 3 rarely had significant complaints. However, there was no evidence or statistical analysis of this observation. Given this gap in the literature, the objective of this study was to evaluate the relationship between the incidence of the different types of degenerative spine disease and lumbopelvic biomechanics, according to the types of lordosis as classified by Roussouly and their correlation with the treatment performed in these patients. Material and Methods: Retrospective study of medical records and results of imaging exams. The sagittal alignment of these patients was evaluated by classifying them according to Roussouly into 4 types, based on panoramic radiographs of the spine. These results were correlated with the patient’s degenerative diagnosis (Herniated disc, Canal stenosis, Spondylolisthesis, degenerative discopathy and Facet arthrosis). Statistical tests were performed comparing the types of curvature and diagnoses identified. Results: 418 patients were evaluated, 51.4% male and 49.6% female. The vast majority of patients, about 54%, had a diagnosis of herniated lumbar disc. There was a statistically significant difference that showed a predilection for surgical treatment in cases classified as Type I and Type II in the Roussouly classification. There was no statistically significant difference that correlated the types of lumbar lordosis with the diagnosis presented by the patients. Conclusion: There is no statistically significant difference that correlates the type of lumbar lordosis according to Roussouly with lumbar degenerative diseases. In contrast, patients classified as Type 1 and Type 2 by Roussouly underwent a greater number of surgical treatments compared to patients type 3 and 4, with statistical relevance. Conclusion: We can conclude that the patients classified as Roussouly type 1 and type 2 underwent surgical treatment in higher numbers than type 3 and type 4 patients. We did not observe any statistical correlation between the type of lumbar lordosis and the type of diagnosis presented. However, a study with a larger sample size (n) is necessary to achieve statistical relevance. Consequently, we have initiated a multicenter study with the same methodology to be conducted through AO Spine LATAM. Devender Singh 1 , Eeric Truumees 1 , Morgan Laviolette 1 , Vik Kohli 1 , Qais Zai 1 , Matthew Geck 1 , John Stokes 1 1 Ascension, Austin, United States Introduction: Spinal surgeries, including fusion, microdiscectomy, and decompression, are essential procedures for treating various spinal pathologies such as degenerative disc disease and spinal stenosis. Despite their widespread use, recovery outcomes vary significantly among patients. Factors such as surgery type, preoperative condition, revision surgery status, and postoperative complications have been implicated in influencing postoperative recovery. This study aims to evaluate the impact of these factors and categorize patients into recovery clusters based on their postoperative outcomes. Material and Methods: A retrospective dataset of 221 patients who underwent spinal surgeries (fusion: 109, microdiscectomy: 72, decompression: 40) was analyzed. Patient outcomes were recorded at multiple time points: preoperative, 3 months, 9 months, and 1 year postop. Preop scores for Physical Function (PF), Pain Interference (PI), Social Role (SR), and Oswestry Disability Index (ODI) were collected. Results: The average age of the patients was 60.7 years, with an age range of 25 to 75 years. Patients were categorized into three recovery clusters based on their outcome trajectories. Cluster 0 (best recovery) included patients who showed the most significant improvement across all outcomes, including PF, PI, and SR. Despite having the worst preop scores (PF = 30.66, PI = 68.47, SR = 36.95, ODI = 59.00), patients in this cluster experienced rapid recovery, particularly in pain reduction and physical function, and no postop complications were recorded. Cluster 1 (modest recovery) exhibited limited improvement across all outcomes. Patients in this group had better preop scores (PF = 36.94, PI = 63.06, SR = 40.20, ODI = 35.00) but showed only modest recovery. This cluster had the highest proportion of non-revision surgeries, and all patients with postop complications were in this group. The presence of complications strongly correlated with modest recovery outcomes (p < 0.01). Cluster 2 (variable recovery) displayed inconsistent recovery, with some patients showing good progress while others had limited improvement. Preop PI was the highest in this group (PI = 71.80), which may have contributed to the variability in recovery outcomes. Logistic regression revealed that patients undergoing microdiscectomy were more likely to belong to this cluster (odds ratio = 2.66, p = 0.02). Statistical analysis using chi-square tests showed a significant association between surgery type and cluster membership (χ 2 = 15.94, p = 0.0031), indicating that surgery type significantly influences recovery trajectories. Postop complications were identified as the strongest predictor of modest recovery (Cluster 1), with all patients experiencing complications falling into this cluster (odds ratio = 3.45, p < 0.01). Conclusion: Preop condition, surgery type, and postoperative complications are key factors influencing recovery trajectories. Contrary to expectations, patients with worse preop scores in Cluster 0 often exhibited the best recovery outcomes, suggesting that initial condition alone is not a reliable predictor of postop recovery. The presence of complications was the strongest determinant of modest recovery (Cluster 1), underscoring the importance of managing postop complications to improve outcomes. The variability observed in Cluster 2 highlights the need for personalized postoperative care. Aécio Rubens Dias Pereira Filho 1 1 Instituto de Acessos à coluna Aécio Dias, São Paulo, Brazil Introduction: Anterior Lumbar Interbody Fusion (ALIF) involves the excision of the intervertebral disc via an abdominal route. Current scholarly reports indicate minimal intraoperative complications across various clinical presentations. Nonetheless, there is a noticeable deficiency in large-scale, population-based primary research that accurately evaluates the rates of intraoperative morbidity. This study aims to evaluate intraoperative parameters of this procedure based on a substantial number of cases. Methods: Patient data were retrospectively collected from the Instituto de Acessos à coluna Aécio Dias (IAAD) database. All patients aged 18 years or older who underwent ALIF were included in the study. Patients who underwent other anterior approaches were excluded. Data on intraoperative morbidity (vascular injury, injury to intra- and extraperitoneal organs, dural sac injury, and nerve root injury), operative time, and bleeding rate were collected and evaluated. Results: A total of 3,438 patients who underwent Anterior Lumbar Interbody Fusion (ALIF) surgery were evaluated. Of these, 1,671 (48.6%) were men and 1,767 (51.4%) were women. The overall average age was 47.87 ± 12.10, with a median age of 46 and an age range from 18 to 88 years. The incidence of complications reported was: vascular injuries (3.25%), nerve root injuries (0.09%), dural sac injuries (0.06%), and injuries to intra and extraperitoneal organs (0.03%). Conclusions: ALIF is a safe procedure with low rates of intraoperative complications. Surgical times and blood loss volumes also appear to be reduced, conforming to the standards reported in the literature. Jiho Jung 1 , Seong-Chan Jung 1 , Jong-Hwan Hong 1 , Moon-Soo Han 1 , Jung-Kil Lee 2 1 Chonnam National University Hospital and Medical School, Neurosurgery, Gwang-ju City, South Korea , 2 Chonnam National University Hospital and Medical School, Neurospine, Gwang-ju city, South Korea Introduction: Thoracic myelopathy caused by the ossification of the ligamentum flavum (OLF) is commonly treated with surgical decompression. This study aimed to compare the clinical and radiological outcomes of surgical decompression without posterior screw fixation (decompressive laminectomy [DL] group) and with posterior screw fixation (laminectomy with screw fixation [LSF] group) for thoracic myelopathy due to OLF with disc degeneration. Material and Methods: A retrospective review of 35 patients (DL group, n = 19; LSF group, n = 16) was conducted. Clinical variables (Japanese Orthopaedic Association scores) and radiological variables (including sagittal vertical axis, pelvic tilt, thoracic kyphosis, sacral slope, lumbar lordosis (LL), segmental Cobb’s angle, dynamic Cobb’s angle, and dynamic thoracolumbar junction [dTLJ] at the operated level) were measured preoperatively and 1 year postoperatively. Results: Both groups exhibited significant improvements in clinical characteristics postoperatively. LL significantly increased at 1 year postoperatively in both groups. Other sagittal alignment parameters did not change significantly. The dTLJ did not differ significantly between the groups preoperatively; however, the dTLJ of the DL group was larger than that of the LSF group at 1 year postoperatively. There was no significant difference between the groups’ dynamic Cobb’s angles or risk of complications. Conclusion: Decompression surgery for OLF resulted in clinical improvement regardless of whether posterior fixation was performed. Decompression without posterior fixation could allow thoracolumbar motion preservation and might be an effective approach for thoracic OLF with disc degeneration. Aiyana Williams 1 , Joshua Lee 1 , Noah Ross 1 , Joe Morrissey 1 , Ashish Ramesh 1 , Eisa Razzak 1 , Haley Nadone 1 , Charlotte Yuan 1 , Hao-Hua Wu 1 , Sohaib Hashmi 1 , Don Park 1 , Yu-po Lee 1 , Nitin Bhatia 1 1 University of California, Irvine, Department of Orthopaedic Surgery, Orange, United States Introduction: Over the past decade, the number of lumbar fusion surgeries has increased significantly. A National Inpatient Sample (NIS) study reported a 62.3% rise in elective lumbar fusions in the U.S. between 2004 and 2015, while another study noted a 95% increase from 2000-2019. This growth is largely due to advancements in surgical techniques, a better understanding of spinal conditions, and the aging population's demand for relief from degenerative spine issues. As the population continues to age, these numbers are expected to rise, with significant economic impacts - spending on lumbar fusions reached $10 billion in 2015 alone. While lumbar fusion has become a standard procedure to stabilize the spine and reduce pain, the growing complexity of surgeries, especially multilevel fusions, has led to higher complication rates. However, the overall impact of patient risk factors on postoperative outcomes across single-level lumbar fusions and multilevel fusions remains unclear. This study aims to assess postoperative complications and comorbidities for patients undergoing lumbar fusion and to determine if they have decreased over the decade. Additionally, this study examines postoperative outcomes, focusing on factors like age, BMI, and pre-existing health conditions. Material and Methods: Utilizing the National Surgical Quality Improvement Program (NSQIP), this retrospective study examined adults who underwent single-level and multilevel posterior lumbar fusion between 2012 and 2022. Variables including patient demographic and comorbid factors and outcome variables such as mortality, reoperation, readmission, length of hospital stay, SSIs, pneumonia, deep vein thrombosis, UTI, bleeding, and sepsis were analyzed. Results: In total, 30,572 patients undergoing lumbar fusion procedures between 2012 and 2022 were identified and analyzed through the NSQIP database. Patients undergoing surgery between 2006 and 2011 were excluded due to a limited sample size. The mean age of all patients was 63.08 years. Poisson regression models identified strong associations between factors such as age, BMI, diabetes, heart failure, steroid use, and smoking with various postoperative complications. Age and BMI were notably linked to higher rates of pneumonia, urinary tract infections, blood transfusions, and deep vein thrombosis. Additionally, diabetes, heart failure, and steroid use were associated with increased risks of wound infections, UTIs, and prolonged hospital stays. Despite these findings, none of the identified risk factors were connected to an increased mortality rate. Conclusion: Although the overall complication rate has remained stable, the increasing prevalence of diabetes and rising BMI among lumbar fusion patients since 2012 is concerning and calls for caution. These growing risk factors, along with age, preoperative steroid use, and congestive heart failure, complicate patient management and emphasize the importance of meticulous preoperative planning. On a positive note, our analysis found no significant association between these risk factors and increased perioperative mortality or sepsis in patients undergoing lumbar fusion from 2012 to 2022. This indicates that while managing more complex patient profiles has become more challenging, it has not led to a higher mortality risk, reflecting the success of current surgical techniques and perioperative care strategies. Stevin Lu 1 , Wyatt Vander Voort 2 , Hania Shazad 2 , Zachary Booze 2 , Dagoberto Pina 2 , Yashar Javidan 2 , Rolando Roberto 2 , Hai Le 2 1 Creighton School of Medicine, Omaha, United States , 2 UC Davis Medical Center, Sacramento, United States Introduction: Sociodemographic differences contribute to poor postoperative outcomes in the affected groups including higher rates of infection, readmission, emergency department (ED) utilization, and longer hospital length of stay. These factors may lead to lower patient satisfaction and increased financial costs. This study aims to explore the association between sociodemographic factors and clinical outcomes following lumbar spine fusion surgery. Material and Methods: Patients aged ≥ 18 years undergoing elective lumbar or lumbosacral fusion surgery for degenerative pathology from 2018 to 2022 at a single academic institution were included. Patients undergoing surgery for trauma, tumor, and/or deformity were excluded. A retrospective review of medical records was conducted. Patient information including age, gender, race/ethnicity, payer status, area deprivation index, social deprivation index, body mass index, Charlson Comorbidity Index, discharge disposition, and hospital length of stay were collected. Return to the emergency department and readmissions within 3 months postoperatively were recorded. Chi-square, two-sample t-test, ANOVA models, and multivariate logistic regression models were conducted for statistical analysis. Results: 484 patients were included. 262 (54.1%) of the patients were male. Majority of the patients were White (80.4%) and non-Hispanic (91.5%). Males (16%; 11.5%) had lower rates of ED utilization and readmissions compared to females (23%; 19.8%; p = 0.053, p = 0.011, respectively). Males were also more likely to be discharged to home (87% vs. 79.3%) than females and less likely to be discharged to skilled nursing facilities (9.2% vs 14.0% for females) and inpatient rehab facilities (3.8% vs. 6.8% for females, p = 0.07). There were no significant differences in length of stay, readmission, return to ED, and discharge disposition between Whites, African Americans, Asians, and Other (p > 0.05). Patients in the Private insurance group had an average hospital length of stay of 3.1 ± 1.7 days compared to 3.8 ± 2.6 days for the Medicare/Medicaid group and 4.7 ± 3.3 days for the Other group (p = 0.005). Medicare/Medicaid group (21.9%; 18.8%) had higher rates of return to ED and readmissions than the Private insurance group (13.2%; 7.6%) and Other group (18.2%; 9.1%; p = 0.068, p = 0.004, respectively). Medicare/Medicaid group were also less likely to be discharged to home compared to the Private insurance group and Other group (77.8% vs. 95.8% for Private group and vs. 90.9% for Other group; p < 0.001). After generating a multivariate model including gender, ethnicity and payer status covariates, both gender and payer status remained statistically significant for readmission to the hospital (p = 0.01, p = 0.008). In the multivariate model for return to ED, both gender and ethnicity variables were approaching significance (p = 0.058, p = 0.09). Additionally, under the multivariate logistic regression model for discharge disposition, gender was statistically significant after controlling for payer status (p = 0.038). Conclusion: This study indicates that the female sex and Medicare/Medicaid payer status demonstrated poorer postoperative outcomes with higher rates of ED utilization and readmission to the hospital. Patients’ race did not have an effect on these postoperative outcomes; however, the small sample sizes for certain races were a limitation. The information in this study can help guide recommendations that aim to target health system-related issues to improve surgical outcomes for patients after lumbar spine surgery. Kevin Mo 1 , Rowen Lin 2 , Giovanni Girgis 2 , William Fang 1 , Shanthan Challa 1 , Taylor Anthony 1 , Ellyn Hirabayashi 1 , Amit Parekh 1 , Hugh Bassewitz 1 1 Valley Health Medical Center, Las Vegas, United States , 2 Touro University Nevada, Henderson, United States Introduction: Same-day anterior-posterior spine surgery can be used to achieve circumferential lumbar fusion. Robotic spine surgery can augment this by allowing for the placement of highly accurate percutaneous pedicle screws. The purpose of this study is to compare the impact of robotic-assisted surgery on outcomes following 1-2 level same-day robotic anterior and posterior lumbar spinal fusion. Material and Methods: Adult patients undergoing 1-2 level anterior and posterior same-day spinal fusion (APF) from 2018-2022 were identified from a single surgeon database. Patients undergoing APF were substratified into two cohorts: 1) Patients undergoing non-robotic surgery 2) patients undergoing robotic surgery. In this analysis, pre-operative, intra-operative, perioperative, six-week, and six-month variables were assessed. Univariate, bivariate, and multivariable regression were performed. All analysis was conducted with Stata 17.0 (College Station, TX). Results: 97 consecutive patients were identified who underwent 1-2 level same-day anterior posterior spinal fusion surgery. Of these patients, 70 underwent robotic surgery while 27 underwent open surgery. The mean age was 51 years old (SD 11), and 46 patients (47%) were female. Using bivariate analysis, patients who underwent robotic-assisted surgery had shorter hospital length of stay (2.85 days vs. 3.62 days; p = 0.018) and greater postop day 1 mobility (200 ft vs. 104 ft; p = 0.036). When controlling for age, levels fused, and operative time, robotic-assisted surgery was still associated with a shorter hospital length of stay (Coeff. [OR], -0.07; confidence interval [CI], -0.14 - -0.01; p = 0.0273), and increased POD1 mobility (OR, 0.0004; CI, 0.00 - 0.00; p = 0.0468). Conclusion: Perioperative hospital length of stay and postop day 1 mobility were found to be independently associated with robotic anterior-posterior same-day spinal fusion surgery when controlling for age, levels fused, and operative time. Further investigation is necessary to confirm these benefits and explore other potential advantages of robotic-assisted spinal fusion. Zhaohai Pang 1,2 , Qiang Yang 2 1 Tianjin Medical University, Tianjin, China , 2 Tianjin University Tianjin Hospital, Tianjin, China Introduction: To investigate the clinical efficacy of lateral lumbar interbody fusion (LLIF) in the treatment of degenerative spinal scoliosis. Material and Methods: A retrospective review was conducted of patients diagnosed with degenerative spinal scoliosis and treated with LLIF surgery at our center from January 2019 to June 2021. Demographic and perioperative data were obtained from their medical records. Relevant radiographic parameters were measured preoperatively, within 3 months postoperatively, and at the final follow-up, including: coronal Cobb angle, distance between the central sacral vertical line (CSVL) and the C7 plumb line, sagittal vertical axis (SVA), lumbar lordosis (LL), pelvic tilt (PT), and the difference between the pelvic incidence (PI) and lumbar lordosis (LL) angles. Clinical outcomes were assessed using the visual analogue scale (VAS) for back and leg pain, and the Oswestry disability index (ODI). Results: A total of 11 patients with 31 LLIF segments were included in this study, with an average age of 65.9 ± 8.0 years. The average follow-up time was 14.0 ± 7.1 months. Except for CSVL-C7 (22.5 ± 17.2 mm vs 22.6 ± 5.7 mm, p = 0.76) and SVA (64.9 ± 42.9 mm vs 41.2 ± 15.9 mm, p = 0.13), all other radiographic parameters showed significant improvement postoperatively compared to preoperative values (p 0.05). Postoperative VAS scores for back pain (5.67 ± 1.12 vs 3.56 ± 0.88, p < 0.05), leg pain (5.44 ± 1.01 vs 3.00 ± 0.87, p < 0.05), and ODI scores (53.7% ± 11.1% vs 34.2% ± 7.8%, p 0.05). Conclusion: For degenerative spinal scoliosis, the LLIF technique can effectively improve coronal deformities and achieve satisfactory overall treatment outcomes. However, its ability to improve SVA is limited, and for patients with more severe sagittal plane imbalance, other techniques may need to be combined for correction. Zhuoya Li 1,2 , Qiang Yang 2 1 Tianjin Medical University, Tianjin, China , 2 Tianjin University Tianjin Hospital, Tianjin, China Introduction: To describe a new method of endoscopic circular saw excision of highly migratory lumbar disc herniation (LDH) under local anesthesia and to report the clinical results at 1-year follow-up. Material and Methods: Retrospective analysis: 21 patients with highly free lumbar disc herniation who underwent percutaneous endoscopic lumbar discectomy with transforaminal drilling approach from June 2019 to August 2020 were analyzed. The Patient-Reported Outcomes Measurement Information System (the Patient-Reported Outcomes Measurement Information System) short form-pain interference (PROMIS-PI) and physical function (PROMIS-PF) were used as clinical outcome assessment tools. Surgical time and complications were recorded. Results: The mean age of the 21 patients (15 males, 6 females) was 37.8 ± 6.0 years (29-52 yrs). The free discs originated from L4/5 in 19 patients and L5/S1 in 2. The mean operative time was 54.1 ± 9.0 min (42-79 min). All patients were followed up to 12 months after surgery. Patients' PROMIS-PI scale T-scores decreased significantly from a mean of 68.6 ± 2.4 points preoperatively to 54.4 ± 1.9 points (p < 0.001) and to 47.1 ± 4.3 at 6 weeks and 12 months, respectively (p < 0.001). PROMIS-PF Scale T-scores decreased significantly from a mean of 26.7 ± 4.7 to 44.3 ± 4.2 (p < 0.001) and to 58.4 ± 4.0 (p < 0.001) at 6 weeks and 12 months, respectively. All patients had no complications and no recurrence of disc herniation during follow-up. Conclusion: The local anesthesia total endoscopic directional laminar drilling technique is a safe, efficient, and cost-effective method of removing highly free LDH. Ben Mohamed Oussema 1 , Meddeb Mehdi 1 , Saadi Chedi 1 , Mestiri Mondher 1 1 Institut Mohamed Kassab, Service Adulte, Tunis, Tunisia Introduction: Spinal fusion has been used increasingly in the treatment of various lumbar diseases. It stops not only the progression of spinal pathology, but it also immobilizes the painful motion segment. However, the increase of mechanical stress and segmental motion at adjacent segments after spinal fusion has been reported especially around the L5-S1 disc. It is assumed that these pathologies occur under the direct or indirect influence of biomechanical changes at adjacent segment to spinal fusion. The aim of our study was to review the long-term behavior of the L5-S1 disc after lumbar fusion. Materials and Methods: This was a retrospective study of patients operated for lumbar arthrodesis. We included all patients having one or multiple levels arthrodesis, above L5 vertebrae. We reviewed clinical, functional and radiological characteristics of L5-S1 disc’s instability with a follow-up of five to ten years. For clinical assessment, we evaluated pain and need to take analgesics. At the functional side, we based our research on the Brodsky score. We used the UCLA Score for the radiological analysis. This score assesses the presence of osteocondensation, osteophytes and decrease of intervertebral disc’s height. Results: Our study included 32 patients operated for lumbar fusion, with a minimal follow-up of five years. The average age was 65 years old. Only two patients had pain around L5-S1 disc, requiring the use of analgesics. Two patients had excellent Brodsky score, 43.75% had good Brodsky score, 15 were classified as fair and one patient had poor Brodsky score. Radiologically, 50% of patients had negative UCLA score, and 18.75% of them had decrease of intervertebral disc’s height. No revision surgery was needed. Conclusion: 6.25% of our patients had symptomatic L5-S1 disc after lumbar arthrodesis, despite the fact that the radiological instability was noted in 50%. Rizwan Mohammad 1 , Shahzaib Baloch 2 1 Doctors Hospital and Medical Centre, Orthopedic and Spine, Lahore, Pakistan , 2 Dr. Ziauddin Hospital, Clifton Campus, Lahore, Pakistan Study design: Retrospective Observational Study. Background: Low back pain is experienced by around 80% of the adult population globally and is one of the most frequent reasons for seeking healthcare. Simultaneously, the prevalence of obesity is rising globally, with around 13% of adults worldwide (11% of men and 15% of women) being obese while 39% of adults (39% of men and 40% of women) overweight in. With the rising prevalence of both obesity and average longevity due to improved health care, this subset of population is more prone to musculoskeletal pain conditions, particularly low back pain. This study was conducted to investigate the relationship between LBP and BMI utilizing Visual analogue score (VAS) & Oswestry Disability Index (ODI). Methodology: Following a thorough retrospective review of data, 2508 patients were included in the study who fulfilled the inclusion and exclusion criteria. All of our patients were over 35 years of age suffering from low back pain with no knee pain at the time of presentation to the clinics. Three major components for evaluation of patients in our study were BMI, Visual analogue score for pain and Oswestry disability. This was a double centre study carried out at Doctor’s Hospital and Medical Centre, Lahore and Dr. Ziauddin Hospital (Clifton), Karachi. Results: Majority of our population, 86% (2164/2508) were either overweight or obese. Upon analysis, it was evident that 82.5% (2070/2508) of the patients with a BMI of 25 and above were suffering from severe disability or crippling pain. 81% (2032/2508) of overweight or obese patients were suffering from severe or very severe pain. Majority 26% (656/2508) of patients with a BMI of over 25 were of Punjabi ethnicity. Conclusion: Our findings underscore the significant interaction between low back pain and BMI, impacting various aspects of patients' lives. The multifaceted nature of this association requires a holistic and interdisciplinary approach for effective management. Keywords: Quality of life (QOL) / Lumbago / Low back ache / Oswestry disability index (ODI) / Visual analogue scale (VAS) Bastian Stemmer 1 , Becker Ralf 1 1 University hospital Augsburg, Department of Neurosurgery, Augsburg, Germany Objective: In the current literature, a connection between the Hounsfield units (HU) measured in CT and osteoporosis has already been demonstrated. Low HUs are therefore also used as a predictor of screw loosening in interbody fusions. The aim of the present study is to examine whether this correlation also applies to the dynamic stabilizations of the lumbar spine. Methods: In a retrospective case series we reviewed 28 consecutive Patients, who underwent a 1 or 2 level dynamic stabilization in lumbar spine due to degenerative disease. The follow-up period for all patients was at least 8 months. In a preoperative CT, the HU in L1, L2 and L3 were measured in three planes each and the mean value was determined for each patient. Screw loosening was assessed by CT. The average HUs were compared between patients with and without screw loosening. Results: There were 12 Patients with screw loosening in CT. The average HU value for these patients was 131. For patients without screw loosening it was 121. The literature indicates a cut-off value for osteoporosis/osteopenia of < 110 HU. Patients with an average HU value 110, screw loosening occurred in 47% of cases. Conclusion: Based on the present results, it may be possible that dynamic stabilization reduces screw loosening in osteoporotic spine. These data need to be verified in larger randomised prospective trials. Zahra Bahroun 1 , Sofien Benzarti 2 , Mohamed Chabaane 1 , Mohamed Amine Triki 2 , Mourad Mtaoumi 2 , Iyadh Ksira 1 1 Sahloul University Hospital, Neurosurgery, Sousse, Tunisia , 2 Sahloul University Hospital, Orthopedic Surgery, Sousse, Tunisia Introduction: Surgery for symptomatic lumbar and lumbosacral spondylolisthesis has proven effective compared to non-surgical treatment. However, the choice of fusion technique remains controversial. The two most commonly used techniques are interbody fusion (PLIF) and posterior lateral fusion (PLF). This study aims to determine if one technique offers advantages over the other in terms of clinical and radiological outcomes. The objective of our study is to highlight the main epidemiological, clinical, and radiological characteristics of spondylolisthesis, to emphasize the advantages and disadvantages of PLIF and PLF in this pathology, and to compare their clinical and radiological outcomes. Methods: Retrospective analytical study in the neurosurgery and orthopedics departments of Sahloul University Hospital in Sousse. Patients with spondylolisthesis operated on between January 2010 and December 2020 were included. Results: Over a period of 11 years, we collected 115 patients with an average age of 52 years with a sex ratio equal to 0.07. 74.8% of patients complained of intermittent radicular claudication, 96.5% of low back pain and 94.8% of radiculalgia. The average preoperative ODI was 29.7 ± 6.06 and the average VAS score was 5.18 ± 2.34. A radiological assessment based on standard radiographs and magnetic resonance imaging showed spondylolisthesis by isthmic lysis in 88.7% and degenerative spondylolisthesis in 11.3%. The patients were divided into two groups according to the planned surgical technique; a PLF group (N = 47) and a PLIF group (N = 68). The results showed a significant difference between the two techniques in the operating time, the intraoperative complication (dural breach), the rate of dural breach at 13.23% in the PLIF group and 4.25% in the PLIF group. of PLF. No difference in the two groups regarding blood loss, length of hospitalization and postoperative complications and clinical outcomes. After 12 months, the average ODI decreased significantly in both groups with no difference between the two. It is of the order of 13.52 ± 2.36 in the PLIF group and 14.2 ± 2.95 in the PLF group, the fusion rate is significantly high in the PLIF group, it is at 96% and 80% in the PLF group. Conclusion: Our series did not show any significant difference in clinical results or postoperative complications between the two surgical techniques. The results showed that PLIF provides statistically high fusion rates compared to PLF. Multicenter studies in Tunisia on these two techniques in cases of spondylolisthesis would be useful to validate these results. Marilina Marques 1 , Miguel Carvalho 1,2 1 Mindset for Performance, Lda, Viseu, Portugal , 2 Hospital CUF Viseu, Viseu, Portugal Sacro-iliac joint (SIJ) pain is often misdiagnosed and left untreated. Treatment options are currently a topic of debate. SIJ pain diagnosis is currently based on specific clinical features and a positive injection test. Once diagnosed treatment options as injection therapy, Radiofrequency ablation ou surgery are considered. This work is the result of a survey to patients with a diagnosis of SIJ pain from a single spine surgeon on a single center. From October, 2018 to May, 2024, 202 patients with the diagnosis of SIJ pain were identified (21,6% of the total of 934 patients with lumbar pain) and phone interviews were conducted by staff members. In this center, patients with this diagnosis are first treated conservatively, then with injections (first with steroids and then with Platelet Rich Plasma (PRP)) and finally, surgery, when the previous treatments fails. Survey was performed on patients who failed conservative treatment and were submitted to infiltration therapy or surgery. Enrolled for survey were 142 patients (70,3% of total) with a response rate of 90,1% (14 non responders). From the 128 patients who responded, 28.9% (37pt) were submitted only to SIJ steroid infiltration, 46,9% (60pt) were also submitted to PRP and 24.2% (31pt) were submitted to SIJ fusion. After undergone only steroid SIJ injection 64.5% of patients reported improvement with the procedure with 90.3% of patients stating moderate, mild or no pain after the procedure. Overall satisfaction rate was of 83.9%. For the PRP treatment, 66.7% of patients reported improvement with the procedure with 80% of patients stating moderate, mild or no pain after the procedure. Overall satisfaction rate was of 75%. For the surgical group, 81.1% of patients reported improvement with the procedure with 75.7% of patients stating moderate, mild or no pain after the procedure. Overall satisfaction rate was of 86.5%. Surgery was performed on 26 pt (70.3%) by percutaneously placement of three triangular section implants crossing the affected SIJ. Two patients needed revision surgery, one for misplaced implant and the other for delayed infection. Both patients had favorable outcomes without consequences. One patient had a unilateral SIJ fusion plus a MISS lumbar discectomy. Two patients had an unilateral SIJ fusion and an anterior lumbar fusion. Eight patients undergone lumbar fusion and bilateral SIJ fusion using S2-I screws and a triangular section implant. Survey results are similar despite the type of surgery. This study states the importance of SIJ as a pain generator with a rate of 21.6% among patients with lumbar pain. Conservative treatment appear to be the weakest treatment as 70.3% of patients end up to perform some form of invasive treatment. Steroid injections have a powerful analgesic effect despite the fact it usually is of short term. The PRP treatment has a fairly good pain control effect, it’s simple and safe and therefore a treatment option were most patients end up to be (46.9% in this survey). Patients submitted to surgical fusion report higher improvement and satisfaction rates with a fairly good pain control. Andy Ton 1 , Apurva Prasad 1 , Marc Abdou 1 , John Shin 1 , William Karakash 1 , Henry Avetisian 1 , Jeffrey C. Wang 1 , Raymond Hah 1 , R. Kiran Alluri 1 1 Keck School of Medicine of USC, Department of Orthopaedic Surgery, Los Angeles, United States Introduction: Preoperative assessment of lumbar alignment parameters typically relies on standing lumbar radiographs. However, lateral decubitus positioning used in lateral lumbar interbody fusions (LLIF) and other lateral-based fusion procedures may alter these alignment parameters. This study investigates the differences in lumbar spinal parameters between standing and lateral decubitus positions and examines their impact on postoperative alignment. Materials and Methods: This prospective cohort study included consecutive patients who underwent lateral lumbar interbody fusion in the lateral decubitus position at a single academic institution from 2021 to 2024. Exclusion criteria were age < 18 years and operative indications for revision, deformity, trauma, infection, or malignancy. Standing measurements were obtained using conventional preoperative and postoperative (immediate and two-week follow-up) lateral lumbar radiographs in neutral position. Lateral decubitus measurements were taken using intraoperative lateral lumbar fluoroscopy (C-arm) imaging. Measured parameters included pelvic incidence, sacral slope, pelvic tilt, global lordosis, segmental lordosis, and disc angle. Paired samples t-test was used to assess differences between preoperative standing and intraoperative lateral decubitus measurements. Spearman's rank correlation analyzed the relationship between these differences and postoperative parameters compared to baseline. Statistical analyses were performed using SPSS 29, with p < 0.05 considered significant. Results: The study included 25 patients (mean age 66.92 years, 76% female), with 52.0% (n = 13) having degenerative spondylolisthesis, 40.0% (n = 10) degenerative disk disease, and 8.0% (n = 2) isthmic spondylolisthesis. Significant differences between preoperative standing and intraoperative lateral decubitus measurements were observed in segmental lordosis at L2/L3 (μ = 2.72, [0.938 to 4.502], p = 0.004) and L3/L4 (μ = 4.36, [2.499 to 6.221], p < 0.001). The magnitude of these differences correlated significantly with immediate postoperative segmental lordosis at L1/L2 (rs = 0.457, p = 0.022), L2/L3 (rs = 0.527, p = 0.007), L3/L4 (rs = 0.694, p < 0 .001), and L4/L5 (rs = 0.531, p = 0.006). At two-week follow-up, significant positive correlations persisted in segmental lordosis at L1/L2 (rs = 0.53, p = 0.008), L3/L4 (rs = 0.515, p = 0.010), and L4/L5 (rs = 0.487, p = 0.016). No other significant differences or correlations were observed in spinopelvic measurements. Conclusions: Lateral decubitus positioning is associated with significant changes in segmental lordosis at L2/L3 and L3/L4 compared to preoperative standing measurements. These differences strongly correlate with changes in postoperative alignment parameters following LLIF. Spine surgeons should be aware of these positional variations between preoperative and intraoperative lumbar parameters and their potential influence on postoperative alignment outcomes. Péter Banczerowski 1 , Csaba Padányi 1 , György Berényi 1 , Zoltán Nagy 1 1 Semmelweis University, Center of Neurosurgery and Neurointervention, Department of Neurosurgery, Budapest, Hungary Introduction: Minimally invasive techniques have evolved in the recent years in the field of spinal surgery. Minimal invasivity has the advantage of minor tissue trauma, shorter hospitalization, earlier recovery, decreased postoperative pain and better cosmetic results and satisfaction. Unilateral biportal endoscopic technique consists of a controlled saline inflow and outflow in order to create an independent working space with wide magnified visual field for optimal decompression. Material and Methods: We analyzed our patients data in a longitudinal study. Inclusion criteria were clinical and radiomorphological diagnosis of lumbar disc herniation and biportal endoscopic surgery between 2019 and 2024 in our Institute. Results: We analyzed 25 patients. 21 of 25 patients (84%) reported significant improvement of symptoms. 4 patients (16%) showed slight postoperative pain. The mean follow-up time was 1 year. We used PROMIS physical function, pain interference short forms and pain intensity numeric rating scale to investigate patient-reported outcome. Mean T-score improvement were 21.8 for physical function, 22.5 for pain interference. Conclusion: Unilateral biportal endoscopic approach has been developed as a minimally invasive spinal surgery technique. Our early results suggest that the method is an effective surgical choice in the treatment of degenerative lumbar disc herniation. The technique could be the alternative of traditional microscopic surgery. Limitation of our study includes small sample size. Joshua Piche 1 , Andy Ton 1 , Avinash Iyer 1 , John Shin 1 , Nicole Hang 1 , Kevin Liu 1 , William Karakash 1 , Henry Avetisian 1 , Jeffrey C. Wang 1 , Raymond Hah 1 , Ram Alluri 1 1 Keck School of Medicine of USC, Department of Orthopaedics, Los Angeles, CA, United States Introduction: Lateral lumbar interbody fusion (LLIF) and anterior lumbar interbody fusion (ALIF) are surgical techniques that can be used for disc height restoration, deformity correction, and indirect spinal decompression. These surgeries can be performed technically from a single lateral decubitus position (SP), or from the lateral decubitus or supine position followed by flipping the patient prone. While evidence suggests single position surgery reduces costs with similar postoperative outcomes, proponents of dual position surgery argue optimal lumbar lordosis can only be achieved with prone positioning. This study represents the most comprehensive single-study assessment of lumbar and pelvic radiographic analyses for single vs dual-position LLIF and ALIF surgeries to our knowledge. Materials and Methods: A retrospective review of patients who underwent either SP lateral decubitus lumbar interbody fusion, or LLIF or ALIF with flip to prone from 2019-2023 was performed at our institution. Demographic data and radiographic pre- and postoperative radiographic measurements including lumbar lordosis (LL), pelvic incidence (PI), and segmental lordosis angles (SL), were collected. Changes in these parameters from preoperative to two weeks and one year postoperatively were compared between groups. Statistical analyses were performed using RStudio, and a p-value of < 0.05 was set as significance. Results: A total of 145 patients, 72 (49.7%) males and 73 (50.3%) females, with an average age of 63.0 years were included. 39 (26.9%) patients underwent SP lateral decubitus lumbar interbody fusion, 31 (21.4%) underwent LLIF with flip, and 75 (51.7%) underwent ALIF with flip. The L3-4 level was included in 38 patients, L4-5 in 79 patients, and L5-S1 in 83 patients. Analysis revealed no statistically significant differences among the three groups in changes to overall lumbar lordosis, pelvic incidence-lumbar lordosis, or segmental lordosis at the operative levels from preoperative to early and late postoperative period. Complication rates, including durotomy (p = 0.14) and vascular injury (p = 0.054) were comparable across all surgical approaches. Conclusion: Our study demonstrates that single-position lumbar fusion achieves comparable lumbar and pelvic radiographic outcomes to dual-position LLIF or ALIF with similar complications rates. These findings support the efficacy of single-position surgery in restoring spinopelvic parameters and contribute to the growing body of evidence establishing it as a viable and successful approach for lumbar fusion procedures. The potential benefits of reduced operative time and cost savings make single-position fusion an attractive option. This evidence encourages the consideration of single-position techniques when appropriate, potentially improving surgical efficiency without compromising outcomes or safety. Fang Xie 1 , Zhuojing Luo 1 , Xueyu Hu 1 1 Xijing Hospital, Xi’an, China Introduction: To explore the impact of isokinetic training of lumbar muscles on exercise ability and quality of life of elderly people with sarcopenia. Material and Methods: From March to May 2024, elderly people aged 60 and above from three communities in local city were conveniently enrolled. Grip strength was measured using a Jamar force gauge, as sarcopenia was diagnosed based on the indicators recommended by the Asian Sarcopenia Working Group (AWGS) (males < 26 kg, females < 18 kg). A total of 104 sarcopenia patients were included. The isokinetic training of lumbar muscles was carried out through Isomed2000 (D&R, Germany). The measurement indicators are peak torque and total work done in flexion, extension, and rotation directions. Indexes of athletic ability include 6m step speed test and 5 sitting and standing tests. Quality of life score is based on the SF-36 Health Survey Brief Form, including physiological total score (PCS) and psychological total score (MCS). The training was conducted three times a week, completing four sets of training at a speed of 60°/s each time. Each set consists of eight flexion extension/rotation cycles, and the training lasts for three months. Results of muscle strength, athletic ability, and quality of life were recorded and compared before and after training. Results: A total of 91 cases completed training. At the end of the training, the grip strength significantly increased compared to before training (24.5 kg vs 22.1 kg, p < 0.01); the peak torque and total work done in the flexion and extension direction of the lumbar muscles significantly increased (p < 0.01), and the peak torque in the rotation direction significantly increased (p < 0.01), with no significant change in total work done; The walking speed of 6m increased compared to before training (1.5 m/s vs 0.9 m/s), and the time for 5 sitting and standing tests was significantly reduced (8.4 m vs 11.3 m); PCS significantly improved (45.4 points vs 33.6 points, p < 0.01), and MCS improved (38.6 points vs 35.4 points, p < 0.05). Conclusion: Isokinetic muscle strength training of the lumbar and back muscles can significantly improve muscle strength, athletic ability, and quality of life in elderly people with sarcopenia. The training may help prevent falls, and maintain the physical and mental health of the elderly. Hugo Arturo González Martínez 1 , Jaime Antonio Sánchez Sandoval 1 , Gustavo Martín González Mendieta 2 , Pablo Tadeo Atlitec Castillo 1 1 South Central High Specialty Hospital, PEMEX, Orthopaedics and Traumatology, Mexico City, Mexico , 2 Corporativo Hospital Satélite, Spine Surgery Unit, State of Mexico, Mexico Introduction: Degenerative spondylolisthesis is the displacement of one vertebral body over another due to arthritic facet changes that cause vertebral instability, leading to spinal canal stenosis and foraminal narrowing, causing low back pain and radiculopathy of varying degree. Surgical treatment is indicated if the symptoms do not subside within 3 to 6 months or with exacerbation of radicular symptoms. Surgical options are based on spinal decompression, spinal fusion or instrumented spinal fusion. The revision surgery rate is up to 35% at 8 years of follow-up. The risk factors mainly associated with revision surgery for degenerative lumbar spondylolisthesis are obesity, diabetes mellitus, smoking, transoperative bleeding, recorded surgical time and surgical technique; however, the international literature is not conclusive, which is why it was decided to carry out this study. The aim of this study is to identify the risk factors that determine revision surgery in patients operated on for degenerative lumbar spondylolisthesis. Material and Methods: Descriptive, cross-sectional and observational study that, by searching for information in the electronic medical record, identified patients who underwent surgery for degenerative lumbar spondylolisthesis in a national hospital center over a 3-year period with follow-up of up to 8 years. Demographic data, preoperative clinical status, treatment and reintervention were evaluated to identify risk factors and their degree of association for revision surgery. Results: The 5-year revision surgery rate was 11% with a male to female ratio of 7:1. A statistically significant relationship was found for presenting revision surgery with a conservative treatment period > 12 months prior to primary surgery (p = 0.000) and transoperative bleeding < 500 ml in primary surgery (p = 0.0453). No statistically significant relationship was found with the variables: age, gender, comorbidities, affected lumbar level, surgical time, cerebrospinal fluid leak, transfusion of blood products and surgical technique. Conclusion: Risk factors associated with revision surgery in patients postoperatively treated for degenerative lumbar spondylolisthesis are: a period of more than 12 months of conservative treatment prior to primary surgery and intraoperative bleeding < 500 ml in primary surgery for degenerative lumbar spondylolisthesis. Emiliano Vialle 1 , Joana Guasque 1 , Otávio Vitório Alvarenga Pereira 1 , João Victor Ferreira 2 , Luis Felipe Pereira 2 , Vinícius Lopes Fruet 1 1 Pontifícia Universidade Católica do Paraná, Hospital Universitário Cajuru, Orthopedics and Traumatology Service, Spine Surgery Group, Curitiba - PR, Brazil , 2 Pontifícia Universidade Católica do Paraná, Curitiba - PR, Brazil Introduction: Degenerative spondylolisthesis is a condition commonly acquired in the fifth decade of life, potentially leading to a spectrum of symptoms such as low back pain, intermittent claudication, and varying degrees of sciatica. There is still no established consensus among spine surgeons regarding the determinant criteria for choosing surgical treatment. Given that it is a multifactorial pathology, patient characteristics such as disc height, presence of osteophytes, facet orientation, sagittal balance, and the degree of vertebral translation must be considered to ensure good postoperative outcomes. This study aims to identify the main factors that influence surgical decision-making in degenerative spondylolisthesis and understand how these factors impact the choice of therapeutic approaches. Material and Methods: A questionnaire was developed using Google Forms, containing 30 representative clinical cases of patients with degenerative spondylolisthesis, including images, radiological measurements, as well as the patients' age and sex. All patients presented with intermittent claudication and mild lower back pain and had not responded successfully to conservative treatment. The questionnaire was sent to 33 spine surgeons from Latin America, who were required to choose between maintain conservative treatment, isolated decompression, or decompression combined with arthrodesis. The inferential analysis was initially performed with objective to identify therapeutic profile patterns (clusters) among the 33 evaluators in the indication of the three treatments. Cluster analysis was used for this purpose. The association between the type of treatment and the clinical characteristics of the case was evaluated using Fisher's exact test. A significance level of 5% was adopted. Statistical analysis was conducted using SPSS software version 26. Results: Data analysis revealed the existence of four clusters with high-quality grouping and significant variation in treatment preferences. Pattern A (15.2% - preference for arthrodesis); B (39.4% - preference for a gradual approach from complex to simple); C (39.4% - arthrodesis as a secondary option); D (6.1% - surgery as a last resort). Evaluators were selected based on significant relationships, at a 5% level, observed within each treatment choice pattern (A, B, C, and D). Variables such as facet angle, type of decompression (unilateral or bilateral), osteophytes, disc herniation, and disc height (Pfirrmann) showed a significant relationship with the type of treatment chosen. Conclusion: The results highlight variables such as facet angle, decompression, presence of osteophytes, disc herniation, and the degree of disc degeneration with a significant impact on the treatment decisions made by spine surgeons when addressing degenerative spondylolisthesis. These findings underscore the need for individualized surgical planning, taking into account the anatomical and radiological aspects of the patients. Elouni Emna 1 , Trifa Amine 1 , Atef Ben Nsir 1 , Wiem Boudabbous 1 , Zohra Souei 1 , Mehdi Darmoul 1 1 Fattouma Bourguiba, University Hospital of Monastir, Department of Neurosurgery, Monastir, Tunisia Introduction: S1 pedicle screws are commonly used as the standard method for sacral fixation in patients with spondylolisthesis. However, improper placement of these screws can result in severe complications. Although the risk of complications is well-recognized, few reports have specifically addressed L5 nerve root injuries that occur when the screws are inserted in an anterolateral direction. Material and Methods: We report the case of a 58-year-old female who presented to our department with left-sided lumbar radiculopathy involving the L5, and S1 nerve roots, along with intermittent claudication. Neurological examination revealed no motor deficit. Imaging confirmed lumbar canal stenosis and L5/S1 spondylolisthesis. The patient underwent L3-L4-L5-S1 fixation, along with L5-S1 laminectomy and foraminotomy. The patient's preoperative symptoms resolved immediately after surgery; however, new right-sided L5 sciatica developed postoperatively. A postoperative X-ray showed no screw malpositioning, and the patient was discharged with medical treatment and physical rehabilitation. Results: At the 3-month follow-up, the patient continued to report right-sided L5 sciatica, which had become severely painful and disabling, though no motor deficits were present. Computed tomography and rootography revealed compression of the right L5 nerve root by the tip of the perforating S1 screw. The patient underwent a second surgery for the removal of the offending screw. In the immediate postoperative period, the right-sided L5 sciatica resolved completely. Conclusion: Surgeons must be aware that anterolateral malpositioning of S1 pedicle screws can result in L5 nerve root injury. It is crucial to ensure precise screw placement and maintain proper fixation to avoid complications. Joshua Bruce 1 , Aakash Shah 1 , Seth Meade 1 , Ghaith Habboub 2 , Mohamed Macki 2 , Michael Steinmetz 2 1 Center for Spine Health, Cleveland Clinic Foundation, Cleveland, United States , 2 Center for Spine Health, Cleveland Clinic Foundation, Department of Neurosurgery, Cleveland, United States Introduction: Transforaminal lumbar interbody fusion (TLIF) is a surgical procedure used to treat spinal instability, radiculopathy, and degenerative disc diseases which has classically been performed utilizing an open technique. Recently, minimally invasive (MIS) TLIF techniques have transformed the procedure with key advantages over open techniques. While the surgical benefits have been extensively studied, the impact of MIS-TLIF on patient satisfaction is relatively unexplored. This study aims to investigate whether MIS TLIF results in changed patient satisfaction, as measured by Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey, compared to Open TLIF. Materials and Methods: A complete review of the electronic medical records of patients who underwent TLIF procedures at the large tertiary care center between 04/2016 and 12/2023 was performed collecting demographic, surgical data, and patient satisfaction as measured by postoperative HCAPHS scores which includes various domains such as communication, pain management, and overall rating of care. When comparing the outcomes between the study groups, continuous variables, categorical variables, and logistic modeling were examined using a Student’s t-test, and chi-square test, respectively. Multivariable logistic analysis was utilized to analyze the impact of surgical and demographic data on postoperative outcomes and satisfaction. A p-value less than 0.05 was considered statistically significant. Results: There were 20 MIS TLIF and 174 Open TLIF procedures included in this analysis. There were no statistically significant differences demographically with respect to age, sex, BMI, smoking history, average follow-up time, race, or ethnic group between groups. Similarly, the average operative time and length of stay was similar between cohorts at 217 minutes and four days, respectively. Patients undergoing MIS-TLIF underwent one level of decompression while all other patients had two or more levels decompressed. There was a statistically significant difference between the two surgical approaches in respect to facetectomy type (p ≤ 0.001). The HCAPHS data for both surgical approaches displayed similar outcomes regarding the questions “Doctor Respectful”, “Doctor Listens”, “Doctor Explains”, “Recommend Hospital”, “Overall Health”, and “Mental Health”. There were statistically significant differences seen with complications with respect to different level of reoperation within one year, 90-day readmission, and 90-day ED visit (p ≤ 0.001) between cohorts, but there were no statistically significant differences seen with respect to postoperative infection, instrument failure, deep vein thrombosis within three months, or revision surgery. Patient’s with increased BMI were less likely to recommend the hospital in their HCAPHS survey (OR: 0.928; 95% CI: 0.859-0.998; p = 0.048). Conclusion: This study demonstrates that MIS and Open TLIF have similar HCAPHS outcomes. Based on these findings, surgeons should utilize the surgical approach they are most comfortable with to achieve the best outcomes for patients. Additionally, the findings of the study will be relevant to help guide improved patient selection, outcomes, and satisfaction. Abhay Nene 1 , Priyank Patel 2 1 Lilavati Hospital, Spine Surgery, Mumbai, India , 2 Jupiter Hospital, Spine Surgery, Mumbai, India Objective: The aim is to study clinical outcome and efficacy of decompression by using spinal process sparing approach by osteotomy and laminectomy by evaluating preoperative and post operative functional scores. Method: This study included 30 patients with confirmed clinical and radiological lumber canal stenosis not improved after 12 weeks of conservative management, age more than 18 years without gross instability with presence of claudication symptoms and radiologically proven with preoperative MRI. The pre and post operative evaluation of patients was done with scores like Oswestry Disability Index (ODI) scores, back pain. VAS scale, leg pain. VAS scale, satisfactory recovery rate- Hirabayashi Method (Based on Pre-op and Post-op JOAS scores). Results: Patients needing long segment decompression due to their multilevel pathology are on serious risk of De stabilisation of the segments. Spinous Process Osteotomy minimizes destruction to tissues not directly involved in the pathologic process, including the paraspinal musculature as well as the interspinous/supraspinous ligament complex and facets and even maintaining their stabilization properties. Thus Spinous Process Osteotomy appears to result in satisfactory spinal decompression with advantages of minimal muscle trauma and post operative discomfort, satisfactory and fast decompression with conventional instruments, maintenance of spinal stability, early mobility, shortening of post op hospital stay, reduction of postoperative back pain and leg pain. Majdi Ben Romdhane 1 , Majdi Sghaier 1 , Bedoui Mootez 1 , Ben theyer Maher 1 , Lafrem Rafik 1 1 Internal Security Hospital, La Marsa, Tunisia Introduction: Standard radiographs and magnetic resonance imaging (MRI) of the spine are generally sufficient for the diagnosis of bipolar spinal stenosis. However, in some cases, computed tomography (CT) and myelography may be required. Neurophysiological studies contribute to differential diagnosis and can also provide prognostic information. While mild, non-progressive cases can sometimes be treated medically, surgery is required in most cases, raising the question of surgical priority. Materials and Methods: Through a retrospective study of 100 cases of arthrosic myelopathy, the authors aimed to highlight the prevalence of bipolar lesions and propose a diagnostic and therapeutic approach according to clinical presentation. Results: All patients suffered from arthrosic myelopathy with a clinical translation. 42 patients initially consulted for cervical osteoarthritis, and clinical examination and radiological examinations revealed signs of lumbar spinal stenosis. In 58 cases, the main complaint was symptoms of lumbar stenosis. The association of the 2 lesions was noted on clinical examination in 60 percent of cases. All patients underwent vertebro-medullary MRI in the event of clinical or radiological suspicion. I n terms of surgical indication, priority was given to the cervical level in 87% of cases. Lumbar surgery led to downstream decompensation and worsening of symptoms in 2 patients, with VAS ranging from 4 to 8, worsening of paresthesia and progression from moderate to severe according to the modified JOA scale. Conclusion: We emphasize the importance of a thorough clinical examination to detect signs of spinal cord or radicular distress. In addition, MRI of the whole spine is crucial in identifying subclinical lesions, underlining its diagnostic value. Majdi Ben Romdhane 1 , Tejouri Achref 1 , Majdi Sghaier 1 , Lafrem Rafik 1 , Ben theyer Maher 1 1 Internal Security Hospital, La Marsa, Tunisia Introduction: Lumbar spinal stenosis is characterized by the narrowing of the spinal canal, caused by various factors including discopathy with posterior disc bulging, hypertrophy of the ligamentum flavum, facet joint arthrosis (zygapophyseal joint arthrosis), and the formation of osteophytes. The condition commonly presents with lumbosciatica and neurogenic intermittent claudication. This study aims to evaluate the effectiveness of surgical treatment in improving patient satisfaction. Materials and Methods: This retrospective study was conducted within the orthopedic surgery department of the Hospital of Internal Security Forces, La Marsa, over a 7-year period (2015-2022). It included 60 patients who underwent posterior decompression and fusion for degenerative lumbar spinal stenosis. Postoperative evaluations focused on improvements in pain and walking distance. Results: The average age of the patients was 62.1 years, with a male-to-female ratio of 2:3. Postoperative assessments revealed a mean improvement of 80% in sciatic pain and 70% in lower back pain. Approximately 30% of patients did not experience improvement, while 70% showed an increase in walking distance. Factors significantly correlated with poorer outcomes included female gender. Conclusion: Lumbar spinal stenosis is a debilitating condition with significant impact on daily life activities. Our results demonstrate that posterior decompression with fusion is an effective treatment modality for symptomatic degenerative lumbar spinal stenosis. Minaam Farooq 1 , Chibuikem Ikwuegbuenyi 1 , Consolata Shayo 1 , Blake Boadi 1 , Jessica Berger 1 , Rachel Bratescu 1 , Roger Härtl 1 1 New York Presbyterian Hospital/Och Spine, Weill Cornell Medicine, Department of Neurological Surgery, New York, United States Introduction: Lumbar interbody fusion (LIF) is a common procedure for treating spinal disorders like degeneration. Various approaches, including posterior (PLIF), transforaminal (TLIF), anterior (ALIF), and lateral (LLIF), have evolved with distinct benefits. A critical long-term complication of LIF is adjacent segment disease (ASDis), which can cause significant pain and require revision surgery. Variability in how ASDis is defined complicates comparison across studies, making reoperation rates a critical outcome measure. This study systematically reviews and compares reoperation rates due to ASDis across different LIF techniques. Material and Methods: A systematic review and meta-analysis followed PRISMA guidelines, and the study protocol was registered with PROSPERO (CRD42024511845). A comprehensive literature search was performed across Medline and Embase from inception to September 2023, focusing on studies reporting reoperations due to adjacent segment disease (ASDis) after LIF surgeries. Eligible studies included randomized controlled trials, cohort studies, and case series with follow-up periods of at least six months. The risk of bias was assessed using the Joanna Briggs Institute, Newcastle-Ottawa, and Cochrane RoB tools. Meta-analysis was conducted using MetaXL software, with heterogeneity assessed using the I 2 statistic. Results: The systematic review identified 653 studies, and 34 were included for analysis. Meta-analysis revealed the reoperation rates due to ASDis following different LIF approaches. For ALIF, based on eight studies (n = 1,514, mean follow-up 71.3 months), the overall reoperation rate was 7.3% (95% CI [5.9.9.1]), with rates of 3% (95% CI [1.5], I 2 = 0%) for follow-up 5 years. For PLIF, 12 studies (n = 3,821) revealed a reoperation rate of 6.1% (95% CI [3.9.8.5]), with 8% (95% CI [4.12], I 2 = 88%) for follow-up 5 years. For LLIF, 9 studies (n = 932) showed an overall reoperation rate of 4.6% (95% CI [2.9.6.7]), with 4% (95% CI [1.9], I 2 = 82%) for follow-up 5 years. For TLIF, the results were divided into open TLIF and MIS-TLIF. For open TLIF, 4 studies reported an overall reoperation rate of 8.5% (95% CI [5.1.12.7]), with 4% (95% CI [0.13], I 2 = 65%) for follow-up 5 years. For MIS-TLIF, 4 studies revealed an overall reoperation rate of 2.8% (95% CI [1.5.4.6]), with 2% (95% CI [0.4], I 2 = 65%) for follow-up . 5 years. Conclusion: This meta-analysis demonstrates significant variability in reoperation rates due to ASDis across lumbar interbody fusion techniques, with MIS-TLIF showing the lowest rates and open TLIF the highest. Reoperation rates tend to increase with longer follow-up durations. However, substantial heterogeneity and potential publication bias in some analyses warrant careful interpretation. These findings highlight the importance of technique selection and ongoing long-term monitoring in managing ASDis risk. Future research should aim to standardize ASDis definitions and investigate factors influencing its development to optimize patient outcomes and minimize reoperation rates. Kevin Mo 1 , Rowen Lin 2 , Giovanni Girgis 2 , William Fang 1 , Shanthan Challa 1 , Taylor Anthony 1 , Ellyn Hirabayashi 1 , Amit Parekh 1 , Hugh Bassewitz 1 1 Valley Health Medical Center, Las Vegas, United States , 2 Touro University Nevada, Henderson, United States Introduction: Prior studies have shown that workers compensation insurance (WC) may be associated with poorer outcomes following surgery. The purpose of this study is to identify whether WC is associated with poor outcomes following 1-2 level same-day anterior and posterior spinal fusion (APF). Material and Methods: Adult patients undergoing 1-2 level APF from 2018-2022 were identified from a single surgeon database. Patients were then substratified into two cohorts: 1) patients who were WC 2) patients who were not WC (non-WC). In this analysis, pre-operative, intra-operative, perioperative, six week, and six month variables were assessed. Univariate, bivariate, and multivariable regression were performed. All analysis was conducted with Stata 17.0 College Station, TX. Results: Approximately 97 consecutive patients who underwent 1-2 level anterior and posterior same-day spinal fusion surgery were identified. Of those patients, 38 (39%) were WC. The average age of all patients was 51 (SD 11), 46 (47%) of patients were female, 60 (62%) used opiates. Upon bivariate analysis, both WC and non-WC cohorts had no statistically significant difference in pre-operative, operative, nor perioperative characteristics. Upon bivariate analysis, WC were more likely to have more pain at six weeks (VAS 4.78 WC vs. 2.83 non-WC; p < 0.001), more pain at six months (VAS 5.67 WC vs. 3.98 non-WC; p = 0.007), and less patient satisfaction at six months (71% WC vs. 88% non-WC; p = 0.035). When controlling for age, levels fused, and operative time using multivariable regression, WC was found to be independently associated with more pain at six months (Coeff. +1.67 VAS; 95% CI .44-2.9; p = 0.0084), lower patient satisfaction at six months (OR 0.25; 95% CI 0.08-0.79; p = 0.0181), and more pain at six weeks (Coeff. +1.97 VAS; 95% CI 0.96-2.98; p = 0.0002). Conclusion: WC was found to be independently associated with increased pain at six weeks and six months, and decreased satisfaction at six months following APF. Furthermore, in this cohort there were no statistically significant differences in pre-operative, operative, nor perioperative characteristics between WC and non-WC. This information can be used to counsel WC patients and adjust surgeon expectations at six weeks and six months. Nizar Borchani 1 , Sirine Ghrissi 2 , Med Hedi Gharbi 2 , Achref Abdennadher 2 , Khalil Amri 2 1 The Principal Military Hospital of Instruction of Tunis, Orthopedics Surgery Department, Tunis, Tunisia , 2 The Principal Military Hospital of Instruction of Tunis, Orthopedic Surgery Department, Tunis, Tunisia Introduction: Surgical treatment of degenerative lumbar pathology is reserved for patients whose symptoms are progressive and resistant to physiotherapy and medication. Posterolateral Fusion (PLF) remains the gold standard in surgery for degenerative lumbar pathology. However, the rate of pseudarthrosis is not negligible. circumferential arthrodesis such as TLIF is a procedure currently in vogue allowing anterior support to be added to arthrodesis and using the same posterior approach. Material and Methods: This was a monocentric retrospective descriptive study conducted at the orthopedic department of the Military hospital of instruction of Tunis over a 5-year period from 2017 to 2022 involving 52 cases. We included patients who had L4 L5 segment surgery for degenerative pathology (Degenerative disc disease, L4 L5 spondylolisthesis with 2 groups: TLIF group and PLF group. Patients with MI-TLIF were excluded from the study. We used the functional score Oswestry Disability Index and the revision rate as a way of assessing surgical technique. Result: The mean age was 51.43 years. 31 patients had TLIF 59%. 21 patients had PLF 41%. The mean ODI in the PLF group improved from 81% to 43%. The mean ODI in the TLIF group improved from 78% to 37%. 5 patients (16%) in the TLIF group had a revision (2 for pseudarthrosis and 3 for adjacent L5/S1 syndrome (9%)). 1 patient in the PLF group had a revision for hematoma. Patients in the TLIF group who underwent revision had poor functional results and a higher mortality rate. There was no significant difference in restitution of segmental and global lordosis in the TLIF group on imaging. Discussion and Conclusion: Arthrodesis of a lumbar segment appears to increase mechanical stress on adjacent segments. This is particularly true for patients who have undergone circumferential arthrodesis, leading to earlier degeneration of the discs. Our study showed no significant difference in ODI improvement between the 2 groups, showing that patients had good release and acceptable restoration of their lumbar lordosis. Patients who underwent TLIF arthrodesis release were at greater risk of developing adjacent syndrome, although this technique appears to be justified in many cases. This leads to a higher rate of revision surgery, with a deterioration in functional outcome. Further work is needed to determinate the optimal surgical technique for fusion in the degenerative lumbar stenosis and spondylolisthesis. Renato Pereira 1 , Pedro Ribeiro 1 , Maura da Silva Cambango 1 , Nubélio Duarte 1 , Renata Marques 1 1 Hospital de Braga, Braga, Portugal Introduction: Effective lumbar fusion and fixation for spinal stenosis require a comprehensive clinical and imaging assessment, including the analysis of spinopelvic parameters. Achieving optimal sagittal balance is crucial for improving quality of life, but the response of these parameters to surgery can vary, complicating the determination of ideal surgical goals. The impact of these parameters in short segment fusions is not well-documented in existing literature. This study investigates the relationship between spinopelvic parameters and the clinical and functional outcomes in patients who underwent short segment fusion surgery for spinal stenosis. Material and Methods: This prospective observational study included patients who received fusion surgery for spinal stenosis at the Neurosurgery Service of Hospital de Braga. We assessed patient demographics, spinopelvic parameters, and clinical and functional outcomes (using VAS and ODI scores) both before and after the surgery. Results: Significant changes were observed only in the PI-LL parameter between pre- and post-operative evaluations. Overall, there was a statistically significant improvement in clinical and functional outcomes following surgery. No particular patient or surgical factors appeared to affect the outcomes. While a clear link between spinopelvic parameters and surgical results was generally absent, normal post-operative T1PA and L1PA values were associated with functional improvements. Specifically, a post-operative T1PA angle below 20° was correlated with reduced pain levels. Conclusion: Patients who experienced substantial functional improvement often had a T1PA ≤ 20° and L1PA ≤ 7.2°, while those with lower pain levels had a T1PA ≤ 20°. The findings indicate a notable enhancement in clinical and functional status after lumbar stenosis surgery. Renato Pereira 1 , Maura da Silva Cambango 1 , Pedro Ribeiro 1 , Nubélio Duarte 1 , Renata Marques 1 1 Hospital de Braga, Braga, Portugal Introduction: This study evaluates the outcomes of L4-L5 and L5-S1 microdiscectomies over the past eight years, focusing on postoperative recovery, incidence of lumbar pain, and recurrence rates. The aim is to determine if certain patients are predisposed to recurrence and whether indirect imaging signs could predict those cases that would benefit from early fixation surgery. Material and Methods: A retrospective review was conducted on patients who underwent L4-L5 and L5-S1 microdiscectomies from 2015 to 2023. Data on hospital discharge times, postoperative lumbar pain, and recurrence rates were collected. Imaging studies, including MRI and CT scans, were analyzed for potential predictive markers of recurrence. Results: Preliminary findings suggest that there were no differences in the length of stay. It also suggests that L5-S1 cases demonstrated a higher prevalence of postoperative lumbar pain, whereas L4-L5 cases seem to show a greater tendency for recurrence. Several indirect imaging signs, such as Modic changes and disc signal intensity on preoperative MRIs, correlated with higher recurrence rates and may be useful to predict those cases more suitable for early spinal fixation surgery. Conclusion: L4-L5 microdiscectomies may show a higher incidence recurrence. Identifying predictive markers on preoperative imaging may help in deciding which cases might benefit from early spinal fixation. Future studies should focus on refining these predictive indicators to optimize surgical outcomes. Thilo Khakzad 1 , Putzier Michael 1 , Janina Serve 1 , Julian Vorpahl 2 , Falko Löffler 2 , Athina Danovasili 1 , Nima Taheri 1 , Lukas Schönnagel 1 1 Charite Universitätsmedizin Berlin, Berlin, Germany , 2 RAYLYTIC Software GmbH, Berlin, Germany Introduction: The intersection of aging, degenerative spinal conditions, and osteoporosis presents a complex clinical challenge, as both degenerative spondylolisthesis and osteoporosis prevalently increase with age. While it is well understood that these conditions often coexist within the aging population, the direct impact of osteoporosis on spinal alignment remains unclear. This study seeks to explore whether osteoporosis contributes to alterations in sagittal alignment parameters in patients with degenerative spondylolisthesis. Materials and Methods: This retrospective analysis focused on non-operative patients diagnosed with degenerative spondylolisthesis at L4/L5, the most prevalent level, attending an outpatient clinic at a tertiary spine center. Exclusion criteria included a history of spinal fusion or spinal metastasis. Osteoporosis was identified through a review of medical records. Sagittal alignment measurements, including Sagittal Vertical Axis (SVA), Lumbar Lordosis (LL), Pelvic Tilt (PT), Pelvic Incidence (PI), and Sacral Slope (SS), were quantified using EOS imaging processed by a validated machine learning algorithm. Both univariable and multivariable regression analyses were employed to explore the relationship between osteoporosis and alterations in sagittal alignment, adjusted for age and sex. Results: This retrospective study included 380 non-operative patients (61.8% female, median age 70, IQR 60 . 77). A total of 24 patients (6.6%) were diagnosed with osteoporosis. The univariable analysis revealed a significant association between osteoporosis and increased Sagittal Vertical Axis (SVA), with osteoporotic patients exhibiting a mean increase of 31.48 mm in SVA (95% CI: 12.81 - 50.16, p = 0.001). This association remained significant after adjusting for age and sex, with a β-coefficient of 29.20 (95% CI: 11.00 - 47.41, p = 0.002), indicating that patients with osteoporosis had, on average, a 29.2mm greater SVA compared to non-osteoporotic patients. No significant associations were found between osteoporosis and other sagittal parameters (LL, PT, PI, SS). Discussion: This study demonstrates a significant relationship between osteoporosis and global sagittal alignment measured by the SVA, in patients with degenerative spondylolisthesis. The pronounced increase in SVA suggests that osteoporosis may exacerbate anterior spinal imbalance, potentially leading to increased pain and functional limitations. These results underscore the importance of considering bone health in the management of patients with degenerative lumbar conditions and suggest that treating osteoporosis could be beneficial in managing the overall severity of spondylolisthesis. Thilo Khakzad 1 , Lukas Schönnagel 1 , Janina Serve 1 , Athina Danovasili 1 , Nima Taheri 1 , Julian Vorpahl 2 , Falko Löffler 2 , Putzier Michael 1 1 Charité Universitätsmedizin Berlin, Berlin, Germany , 2 Raylytic Software Gmbh, Leipzig, Germany Introduction: Degenerative scoliosis is a common condition in older adults and is frequently accompanied by hip osteoarthritis (OA). Understanding the impact of hip OA on sagittal spinal alignment is critical for optimal patient care. This study aims to investigate the relationship between hip OA and sagittal alignment parameters in patients with degenerative scoliosis, with the goal of identifying key associations that could inform clinical decision-making. Materials and Methods: This retrospective analysis included non-operative patients diagnosed with degenerative scoliosis. Exclusion criteria included a history of spinal fusion, fractures or spinal metastasis. Osteoarthritis was classified using the Kellgren and Lawrence classification, ranging from 0 to 4. Sagittal alignment measurements, included Sagittal Vertical Axis (SVA), Lumbar Lordosis (LL), Pelvic Tilt (PT), Pelvic Incidence (PI), and Sacral Slope (SS) which was assessed in EOS full spine radiographs. A validated machine learning algorithm was used to measure these parameters. Both univariable and multivariable regression analyses were employed to explore the relationship between osteoporosis and alterations in sagittal alignment, adjusted for age, sex, and the degree of intervertebral osteochondrosis. Results: A total of 731 patients (median age 68 years, IQR 56.5.77) diagnosed with degenerative de novo scoliosis were included in the study. Of the total cohort, 435 patients (59.5%) were diagnosed with hip osteoarthritis, as indicated by a Kellgren and Lawrence grade of at least 1. In the univariable analysis, significant associations were observed between hip osteoarthritis and several sagittal alignment parameters. The multivariable regression analysis, adjusted for age, sex, and osteochondrosis, demonstrated a significant positive association between hip OA and SVA (β: 3.85, 95% CI: 0.74 - 6.97, p = 0.015), indicating that patients with more severe hip OA were exhibited a larger forward shift in sagittal balance. A negative association was found between hip OA and pelvic tilt (PT) (β: -1.48, 95% CI: -2.15 - -0.81, p < 0.001), while sacral slope (SS) was positively correlated with hip OA (β: 1.08, 95% CI: 0.38 - 1.78, p = 0.003). Additionally, a significant negative correlation between hip OA and the lumbar Cobb angle was identified (β: -1.52, 95% CI: -2.36 - -0.68, p < 0.001), suggesting that patients with more advanced hip OA tend to have a small but statistically significant reduced coronal lumbar curvature. Discussion: The results of this study highlight a significant relationship between hip osteoarthritis and sagittal spinal alignment in patients with degenerative scoliosis. Specifically, the forward shift in sagittal balance (SVA) and alterations in pelvic parameters (PT and SS) suggest that hip OA influences spinal alignment compensatory mechanisms. The negative association with the lumbar Cobb angle further underscores the complex interactions between the hip and spine in degenerative conditions. Clinicians should be mindful of these interactions when evaluating and treating patients with combined hip and spinal pathologies, as these findings suggest a broader influence of hip OA on spinal alignment that may affect treatment strategies. Kevin Mo 1 , Rowen Lin 2 , Giovanni Girgis 2 , William Fang 1 , Shanthan Challa 1 , Taylor Anthony 1 , Ellyn Hirabayashi 1 , Amit Parekh 1 , Hugh Bassewitz 1 1 Valley Health Medical Center, Las Vegas, United States , 2 Touro University Nevada, Henderson, United States Introduction: Patient satisfaction is an important measure of quality of care following spine surgery. Same-day anterior posterior circumferential spine surgery is a reliable technique used to achieve a successful lumbar arthrodesis. The purpose of this study is to identify predictive factors for six month patient satisfaction following 1-2 level same-day anterior and posterior spinal fusion. Material and Methods: Adult patients undergoing 1-2 level anterior posterior same-day spinal fusion (APF) from 2018-2022 were identified from a single surgeon database. Patients undergoing APF were substratified into two cohorts: 1) patient’s satisfied at six months 2) patients not satisfied at six months. In this analysis, pre-operative, intra-operative, perioperative, six week, and six month variables were assessed. Univariate, bivariate, and multivariable regression were performed. Threshold regression analysis was utilized to determine thresholds for continuous variables when significant on bivariate analysis. All analysis was conducted with Stata 17.0 College Station, TX. Results: Approximately 97 consecutive patients who underwent 1-2 level anterior posterior same-day lumbar fusion surgery were identified. Of those patients, 79 (81%) were satisfied at six months. The average age of all patients was 51 years old (SD 11), 46 patients (47%) were female, 60 (62%) used opiates, 7 (7%) had a prior laminectomy surgery. Using bivariate analysis, when compared to unsatisfied at six months, the satisfied patients were less likely to be opiate users (57% vs. 83%; p = 0.038), less likely to have had prior laminectomy (4% vs. 22%; p = 0.006), less likely to have postop day #1 (POD1) Mobility < 200 feet (63% vs. 89%; p = 0.036). The satisfied patients were more likely to have higher POD1 mobility (197ft vs. 54ft; p = 0.007), lower visual analog (VAS) score (4.79 vs. 8; p < 0.001), VAS score < 5 at week six (61% vs. 6%; p < 0.001), be satisfied at week six (94% vs. 50%; p < 0.001), and have experienced a larger drop in VAS score by week six (-3.13 vs. +.17; p < 0.001). By month six satisfied patients had a lower VAS score and experienced a larger drop in VAS score (-4 vs. -1; p < 0.001). Finally, using multivariable analysis, no prior laminectomy (OR 59.97; CI 0.00-0.41; p = 0.012), week six VAS < 5 (OR 17.4; CI 1.91-158; p = 0.0113), week six satisfaction (OR 11.59; CI 1.78-75.43; p = 0.0103; and no opiate use pre-operatively (OR 13.86; CI 1.33-143; p = 0.0276), are associated with increased odds of patient satisfaction at six months postoperatively. Conclusion: Upon multivariable analysis, week 6 satisfaction, week 6 VAS < 5, no prior laminectomy, and no prior opiate use were found to be independent risk factors for six month satisfaction following anterior posterior same-day spinal fusion surgery. This information can be used to counsel patients and adjust expectations, pre-operatively, perioperatively, and at the six-week visit. Rowen Lin 1 , Kevin Mo 2 , William Fang 2 , Shanthan Challa 2 , Daniel Lee 2 1 Touro University Nevada, Henderson, United States , 2 Valley Health Medical Center, Las Vegas, United States Introduction: Performing an adjacent laminectomy procedure during index fusion is a potential treatment for spondylolisthesis with adjacent-level stenosis. Development of adjacent segment complications is a well researched risk factor when performing lumbar fusions. However this is the first systematic review documenting the adjacent segment degradation in patients that have had an adjacent-level laminectomy performed in addition to a lumbar fusion. Material and Methods: The systemic review was conducted using PubMed, Embase, and Cochrane Library databases in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of the evidence was evaluated using Newcastle-Ottawa Scale (NOS). All statistical analyses were performed using STATA. Results: A total of 7 studies were included in the final review comprising of 351 patients. The overall rate of complication (i.e. spondylolisthesis, osteophytes, disc height narrowing, endplate sclerosis) development at the adjacent segment overall was 43.7% with a range of 8.8% - 67.56%. There was no noticeable trend relating the number of levels fused to the development of ASD after the laminectomy procedure, ranging from 12.6% - 32.4%. There was also no significant evidence that the development of symptomatic ASD would lead to required revision surgery, ranging from 2.2% - 100%. Conclusion: Adjacent laminectomy during an index lumbar spinal fusion shows a high chance of the development of adjacent segment complications with a further potential risk of needing revision surgery. With only 7 articles included in the final analysis, this indicates that there is a current limitation in the amount of literature regarding this topic. Further studies should also be conducted to determine if radiographically determined ASD will result in a necessary revision surgery after adjacent laminectomy plus fusion. Sami Bahroun 1 , Anis Bouaziz 1 , Mohamed Samih Kacem 1 , Masmoudi Zied 1 , Mohamed Samir Daghfous 1 1 Kassab Hspital, Orthopaedic Department B, Tunis, Tunisia Introduction: The management of low-grade degenerative spondylolisthesis remains a topic of debate, particularly regarding decompression alone by laminectomy versus decompression combined with posterolateral fusion. This study aims to compare the clinical outcomes of these two approaches. Methods and Materials: This retrospective cohort study involved two groups of patients with low-grade degenerative spondylolisthesis. The first group underwent decompression alone by laminectomy, and the second group underwent decompression combined with posterolateral fusion. We evaluated the level and the degree of spondylolisthesis according to Meyerding classification. The clinical outcomes were assessed by the Visual Analog Scale (VAS) for radicular and lumbar pain, the Oswestry Disability Index (ODI), risk of reoperation, as well as perioperative complications such as blood loss, operative time, and symptom recurrence. Results: A total of 68 patients were included in the study: 36 patients underwent fusion, and 32 underwent laminectomy alone, with an average follow-up of 2 years. In 55 patients, the affected level was L4-L5, in 10 patients L5-S1, and in 3 patients L3-L4. According to Meyerding, 48 patients were classified as Grade 2, and 20 as Grade 1. Preoperatively, the mean ODI score was 38.24 ± 5.3 in the fusion group and 37.58 ± 6.47 in the laminectomy group, improving postoperatively to 18.25 ± 2.4 and 24.87 ± 4.56, respectively. The difference in postoperative ODI scores between the two groups was statistically significant (p < 0.000). The preoperative VAS scores for the fusion group were L 6.8 and R 7.84, and for the laminectomy group L 5.24 and R 6.35, improving postoperatively to L 2.54 and R 1.2 for the fusion group, and L 3.8 and R 2.47 for the laminectomy group. Statistically significant differences were observed between the two groups for both lumbar pain (p < 0.000) and radicular pain (p < 0.000), favoring the fusion group. There was no statistically significant difference in the risk of reoperation between the two groups. Symptom recurrence was similar, though the fusion group had a higher risk of perioperative blood loss. Conclusion: While both surgical approaches effectively managed degenerative spondylolisthesis, combining laminectomy with fusion led to greater improvements in function and pain reduction. However, it was associated with a higher risk of blood loss during surgery. Saif Toumi 1 , Majdi Ben Romdhane 2 , Alaa Lessoued 1 , Ben Amara Mohamed Amine 1 , Annabi Hedi 1 1 Ben Arous Orthopedic and Trauma Center, Orthopedics, Tunis, Tunisia, 2 La Marsa Interior Forces Hospital, Tunis, Tunisia Lumbar spinal stenosis (LSS) is a disabling spinal condition primarily caused by degenerative processes resulting in an imbalance between the container (bony canal) and the contents (dural sac and nerve roots). The aim of our study was to report the clinical, functional, and radiological outcomes of surgical treatment for LSS based on lamino-arthrectomy. Methods: This was a retrospective study over a 4-year period involving patients undergoing lamino-arthrectomy at the orthopedic surgery department of the Hospital of the Internal Security Forces in La Marsa. We included 37 patients with LSS who underwent lamino-arthrectomy and instrumented posterolateral fusion. Evaluation was based on clinical, anamnestic, radiological data, calculation of the Oswestry Disability Index (ODI), and patient satisfaction assessed through the Swiss Spinal Stenosis Score (SSS). Results: The mean age of our patients was 42.95 years with a sex ratio of 1.84. All patients had neurogenic claudication with a walking perimeter limitation, 62% with a walking distance < 200 meters. Motor deficit was observed in 14.5% of cases and sensory deficit in 19% of cases. The most stenotic levels on MRI were L4-L5 followed by L5-S1. All patients underwent surgical treatment with lamino-arthrectomy and posterolateral fusion; on a single level in 1 patient, on 2 levels in 23 patients, on 3 levels in 12 patients, and on 4 levels in 1 patient. The ODI score decreased from 65.59 preoperatively to 35.94 postoperatively. The Visual Analog Scale (VAS) score decreased from 8.36 preoperatively to 3.7 postoperatively. 94.6% of patients were satisfied with the surgical treatment. Radiological evaluation showed only one patient with adjacent segment degeneration syndrome (ASD). Conclusions: Lamino-arthrectomy is an effective surgical technique for posterior and lateral decompression of the lumbar canal. Its indications have expanded with the advent of instrumented posterolateral fusion. Our study demonstrated its effectiveness in reducing pain and improving the functional status of patients. Dmitry Dzukaev 1 , Alexander Peyker 1 , Anton Borzenkov 1 , Mikhail Safronov 1 , Georgiy Malyakin 2 3 , Eduard Bezuglov 2 1 City Clinical Hospital 67, Moscow Spine Center, Moscow, Russian Federation , 2 Sechenov First Moscow State Medical University, Department of Sports Medicine and Medical Rehabilitation, Moscow , Russian Federation , 3 Sechenov First Moscow State Medical University, High Performance Sports Laboratory, Moscow, Russian Federation Introduction: The main type of surgery for spinal canal stenosis with spondylolisthesis is currently spinal canal decompression combined with segment stabilization consisting of spondylolisthesis reduction using a rigid system and interbody cages. Rigid systems have a number of disadvantages, such as disruption of biomechanics in adjacent segments, the long time required for true fusion to occur in the operated segment, and, consequently, limitations in terms of physical activity, which is possible only after the fusion formation. Usually, these disadvantages make it truly impossible for professional athletes to continue their careers. We describe a clinical observation of the treatment of an adult professional football player who played for a team of the highest division of the country from 2010 to 2020 that was in the top-10 UEFA rankings, with spinal canal stenosis of the lumbar spine due to spondylolysis antespondylolisthesis with neurological deficit. The proposed tactics of two-stage surgical treatment of the patient allowed him to return to regular training in the general group in 6 months after the first stage of surgical intervention and to continue to practice sports at a professional level without restrictions. Material and Methods: The method of two-stage surgical treatment aimed at the fusion formation. The first stage included microsurgical decompression of neural structures, without spondylolisthesis reduction, with preservation of the posterior support complex (facet joints) in combination with rigid spine at L4L5S1 level, with complete regression of clinical manifestations of the disease. Return to active physical activity in 2.5 months, continued professional football career in 6 months after surgery. The patient was warned that due to the increased load on the rigid system, the probability of peri-implant resorption and possible system failure, after 12 months he will have to undergo the second stage: surgical replacement of titanium rods with semi-rigid dynamic rods, which, in combination with the forming posterior fusion (in the area of facet joints) will allow him to continue playing, training process without restrictions immediately after the healing of soft tissues. Results: The preoperative VAS score was 70 points, which was interpreted as moderate pain; according to the Oswestry questionnaire, the preoperative quality of life impairment score was 48%, which corresponded to a severe impairment (the patient's pain becomes the main problem, the activity of daily life is difficult for him). Postoperatively, the VAS is less than 5 points, the Oswestry was 4% - minimal impairment (the patient can perform all daily activities). Conclusion: We have described a case of a patient returning to professional sports with such combination of pathologies and a surgical treatment option. There are enough descriptions in the literature of patients with herniated discs and spondylolysis who have undergone surgical treatment, but these cases involved no more than one segment, neurologically intact patients, and the time of resumption of professional career varied from 12 to 14 months. Further monitoring and the creation of a unified database of athletes with similar diseases is needed to unify treatment protocols for patients with an initial very high level of physical activity. Elouni Emna 1 , Atef Ben Nsir 1 , Ghorbal Mohamed 1 , Wiem Boudabbous 1 , Zohra Souei 1 , Affes Ameur 1 1 Fattouma Bourguiba, Universirty Hospital of Monastir, Department of Neurosurgery, Monastir, Tunisia Introduction: Congenital scoliosis, even in the presence of a double vertebral block, can initially be asymptomatic. Nonetheless, symptoms may emerge later as a result of degenerative changes. Material and Methods: A 45-year-old woman with a history of congenital scoliosis and double vertebral block presented to our department with left lumbar radiculopathy and heaviness in the left lower limb. Her congenital scoliosis had previously been asymptomatic. Clinical examination revealed an L4 motor deficit. Imaging studies identified hypertrophic ligamentum flavum at the L3-L4 level and foraminal stenosis contributing to the patient's symptoms Results: Given the findings, the patient was proposed for an in situ decompression procedure, specifically a left-sided L3-L4 foraminotomy without fusion. This approach aims to relieve nerve root compression without extensive intervention, addressing the patient's symptoms effectively while minimizing surgical risk. Conclusion: A minimally invasive approach for symptom relief in patients with complex spinal anomalies is often considered a prudent decision. However, its effectiveness in our specific case remains to be seen. We are currently awaiting results. Jackson Daniel 1 , Luis Eduardo Carelli Texeira da Silva 2 , Denise Silva 3 , Ana Raquel Visgueira 3 , Jose Alberto Oliveira 4 1 University Hospital of Federal University of Piaui, Neurosurgery, Teresina, Brazil , 2 National Institute of Traumatology and Orthopedics, Spine Surgery, Rio De Janeiro, Brazil , 3 Estadual University of Piaui, Teresina, Brazil , 4 Federal Unniversity of Ceara, Fortaleza, Brazil Introduction: Degenerative lumbar stenosis is a prevalent condition that causes neural compression and various debilitating symptoms. Currently, there are different minimally invasive surgical techniques available for its treatment, including uniportal and biportal endoscopic decompression. However, the existing literature presents conflicting results regarding the efficacy and safety of these approaches in comparison. Therefore, this systematic review aims to compare the clinical, functional, and safety outcomes between uniportal and biportal endoscopic surgery for the treatment of degenerative lumbar stenosis. Material and Methods: A systematic search was conducted across PubMed, Cochrane, Embase and Scopus databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search utilized keywords including “spinal stenosis”, uniportal endoscopy”, “endoscopic discectomy biportal,”,”recovery time” and “ functional improvement”. The review encompassed articles published from 2000 to 2024, resulting in a total of 72 studies identified for analysis. These studies were screened and evaluated by three independent reviewers. Data on time of surgery, pain improve, and complication rates were collected when available to facilitate a comprehensive comparison between patients undergoing uniportal and biportal endoscopic spinal surgery. Results: Nine studies involving a total of 462 patients were included in the analysis. Overall, the biportal technique had a longer operative time, with an average of 106.7 ± 25.1 minutes, compared to the uniportal technique. However, the biportal technique resulted in greater pain improvement, with an average reduction of 3.44 ± 1.22 points on the Visual Analog Scale (VAS), while the uniportal technique showed a less significant pain reduction. Complication rates were similar between the two groups, with the biportal group reporting only one case of mild headache, which resolved with rest. Studies like Gu et al. (2021) supported these findings, showing significant functional improvement, with a 30.3 ± 13.1% reduction in the Oswestry Disability Index (ODI), comparable to the results of the uniportal technique. Conclusion: The biportal endoscopic spine surgery technique showed a longer operative time compared to the uniportal technique but provided superior pain relief. Despite the longer surgical time, complication rates were similar between the two techniques. These findings suggest that the biportal technique may be a favorable option for patients seeking more effective pain relief, while the uniportal technique may be preferred in cases where a shorter operative time is prioritized. Further studies are needed to better define the patient profiles that benefit most from each technique. Diego Nuñez 1 , Baron Zarate Kalfopulos 2 , Carla García-Ramos 3 , Ernesto Roldan 4 , Diana Laura Hernandez Moctezuma 2 1 Instituto Nacional de Rehabilitación, Spine Surgery, Orthopedia, Mexico City, Mexico , 2 Instituto Nacional de Rehabilitación, Spine Surgery, Mexico City, Mexico , 3 Instituto Nacional de Rehabilitación, Spine Surgery, Mexico City , 4 Instituto Nacional de Rehabilitacion, Image and Investigation, Ciudad de Mexico, Mexico Introduction: Degenerative spondylolisthesis is a leading cause of lower back pain and disability, often necessitating effective surgical intervention. This study evaluates fusion rates across various anatomical regions of the lumbar vertebral body and their correlation with clinical outcomes in patients undergoing transforaminal lumbar interbody fusion (TLIF). Material and Methods: This retrospective study analyzed data from 88 patients with degenerative spondylolisthesis who underwent 360° TLIF at the Mexican National Rehabilitation Institute between January 2017 and May 2022. Postoperative CT scans assessed fusion in seven anatomical zones. Clinical outcomes were measured using the Oswestry Disability Index, the SF-36, and Roland-Morris questionnaires. Results: The L4-L5 level was the most commonly affected (43.1%), followed by combined L4-L5 and L5-S1 levels (35.3%). High fusion success rates were noted, particularly in intersomatic regions (89.6%, p < .0001) and facet joint fusions. Complications included pedicle fractures (3.9%), durotomy (2.0%), dural injury (7.8%), and nerve alterations (3.9%). No significant correlations were observed between fusion locations and improvements in clinical outcomes (SF-36, p = .7124; Oswestry PCS, p = .9943; Oswestry MCS, p = .6457; Roland-Morris, p = .4255). Female patients exhibited higher success rates in several types of fusion compared to male patients (p < .01). Conclusion: This study confirms that TLIF achieves high fusion rates, particularly in intersomatic and facet joint fusions, and indicates that the fusion location within the lumbar vertebral body may not significantly impact clinical outcomes. These findings highlight the critical role of surgical expertise and patient optimization strategies. Further research involving larger sample sizes and extended follow-up periods is essential to validate these results and examine long-term outcomes. Ivan Tulić 1,2 , Jovan Peric 2,3 , Milos Vasic 1 , Uros Novakovic 1,2 , Milos Mladenovic 1,2 , Valerija Teodosic 1,2 , Slavisa Zagorac 1,2 1 Clinic for Orthopedic Surgery and Traumatology, University Clinical Center of Serbia, Spinal Surgery, Belgrade, Serbia , 2 Faculty of Medicine, University of Belgrade, Belgrade, Serbia , 3 Center for Anesthesiology and Resuscitation, University Clinical Center of Serbia, Belgrade, Serbia Introduction: Degenerative lumbar spondylolisthesis (DLS) is a common spinal pathology with an estimated prevalence between 25% - 43% in women and 19%-31% in men over 65. DLS often leads to neurogenic claudication, low back pain or leg pain (radiculopathy). This condition often requires surgical intervention, as it was reported to be superior to conservative treatment (SPORT trial). The two commonly used methods are decompression alone or decompression plus fusion, however there is a large variation of practice worldwide with decompression plus fusion being often the method of choice. The aim of this review was to analyse recently published studies in order to determine the effectiveness of decompression alone in treatment of DLS. Material and Methods: A literature search of PubMed/MEDLINE and EMBASE databases was performed. Relevant articles assessing decompression surgery for the treatment of DLS published in the last 5 years were included in this review. Results: Seven randomized controlled studies were included in this review. The pooled data revealed that decompression alone had similar outcomes in terms of ODI, leg and back pain score compared to decompression plus fusion. Furthermore, decompression alone is associated with less intraoperative blood loss, operative time and hospital stay. However, reoperation rate in patients who underwent decompression alone surgery was slightly higher compared to decompression plus fusion. Conclusion: Decompression is an effective method for treating DLS, however more evidence is needed in order to make clear guidelines for the treatment of this spinal pathology and possibly affirm decompression alone as the method of choice for treating DLS. Pedro Torres 1 , Andre Castilho 2 , Allan Jose Lima Bueno 2 , Eliane Cristina de Souza Soa 2 , Fabiano Soares Carneiro 2 , Daniel Araujo 2 1 Hospital Unimed, Belo Horizonte, Brazil , 2 Hospital Mater Dei, Belo Horizonte, Brazil Introduction: Postoperative pain management in spinal surgeries remains a challenge, and the erector spinae plane (ESP) block has emerged as a promising analgesic technique, offering significant benefits in pain reduction and opioid consumption. This prospective case series aimed to evaluate the efficacy and safety of ESP block in patients undergoing elective lumbar surgeries. The lack of published articles and the discrepancy between some data motivate the performance of this study, which aimed to preliminarily evaluate the use of ESP block as an analgesic technique in lumbar spine surgeries. Material and Methods: A case series of 3 patients aged 18 to 60 years undergoing surgeries of up to two levels were included, with bilateral ESP blocks performed in conjunction with general anesthesia before the start of surgery. Patients with central neurological disorders (including cognitive impairments), coagulation disorders, chronic opioid use, infection at the paravertebral puncture site, previous spinal surgeries, allergy to any study drug, and inability or refusal to verify the informed consent form were excluded. Data were collected in the Post-Anesthesia Care Unit and at 6, 12, 24, and 48 hours postoperatively. The analysis included pain intensity, opioid use, and the occurrence of side effects. For statistical analysis, the patients' profile was characterized by absolute frequency, relative frequency, mean and standard deviation. Data normality was verified by the Shapiro-Wilk test. Data comparison throughout the intervention was performed using paired t-tests and Friedman's ANOVA. Data were analyzed using the Statistical Package for Social Science (IBM Corporation, Armonk, USA) version 26.0. The significance level adopted was 5% (p < 0.05). Results: Results demonstrated that the ESP block provided satisfactory analgesia, with low morphine usage and no significant adverse effects. Postoperative pain was effectively controlled, with no prolonged hospitalization or block-related complications. Conclusion: Although this study is limited by its case series design, ESP block appears to be a promising strategy for pain control in patients undergoing lumbar spine surgery. However, additional studies are needed to confirm these findings and to further explore the potential benefits of the block regarding functional recovery and patient satisfaction. Future investigations may include a larger sample of patients and comparisons with other analgesic techniques. Marco Gonzalez-Gomez 1 1 Hospital Clínica Nova, Neurosurgery, Spine Surgery, San Nicolas de los Garza, Mexico Introduction: Lumbar intersomatic fusion is used to treat many lumbar spine conditions, such as spinal stenosis, spondylolisthesis, and spinal deformity. Recently, minimally invasive techniques using a tubular retractor have shown that they preserve a significant portion of the lumbar musculature. Many studies have reported that minimally invasive TLIF (MIS-TLIF) provides comparable treatment to other fusion methods. However, in MIS-TLIF, the annulectomy and disc resection are performed unilaterally, and only one cage is inserted, which may result in a smaller disc space preparation area compared to conventional bilateral PLIF. This has raised concerns about whether, in the long term, the fusion rate is lower than that achieved with conventional PLIF. Nevertheless, one advantage of MIS-TLIF is that it minimizes the impact on the treated level and the adjacent segment by preserving surrounding structures and soft tissues, especially on the contralateral side. Consequently, compared to conventional open techniques, MIS-TLIF is less likely to cause degeneration of the adjacent segment (ASD). However, there is a lack of long-term follow-up studies, as most reports have a maximum follow-up of 5 years. Furthermore, there are no studies specifically including workers subjected to strenuous workloads. Material and Methods: Study Type and Design: Cross-sectional, observational, retrospective, and descriptive study. Inclusion Criteria: Patients over 18 years old who were admitted to the Neurosurgery and Spine Clinic at Hospital Clínica Nova in Monterrey, Nuevo León, México between November 1, 2018, and May 1, 2020, with clinical and radiological criteria for lumbar spine disease requiring fusion surgery at one level from L1-2 to L5-S1, who underwent the procedure using the MIS-TLIF technique at the institution, and have clinical and radiological follow-up of at least 24 months. Exclusion Criteria: 1. Patients whose collected information is incomplete regarding the study objectives. 2. Patients with a history of previous lumbar surgeries. 3. Patients with clinical evidence of infection. 4. Patients with any disease or who take any medication that affects bone quality. Results: The scores on the Oswestry scale improved from 65.2% to 20.1% (p < 0.001). The VAS score decreased from 7.3 to 3.4 (p < 0.001). Patient satisfaction was 83%. Fusion was observed in 94.4% (17/18) of cases. One patient (5.5%) experienced transient dysesthesias that resolved within 2 months. Return to work occurred at 6 weeks. Conclusion: Minimally invasive instrumentation at one level using the MIS-TLIF technique provides satisfactory clinical and radiological results at 2 years in patients subjected to demanding physical workloads, such as those in the steel industry. Mohammed Moussa 1 , Ahmed Saber 1 1 Fayoum University Hospital, Orthopedic Surgery Department, Spine Unit, Fayoum, Egypt Introduction: To report nine cases of multiple-level spondylolysis and evaluate the effectiveness of surgical repair in relieving the patient’s pain scores and improving their quality of life, in addition to exploring possible alternative management plans. Material and Methods: We followed the CONSORT guidelines during the preparation of this study. Patients with multiple-level spondylolysis were included. We compared postoperative lower back pain (LBP), leg pain, and Oswestry disability index (ODI) during a follow-up period of 12 months with baseline values. The pain was assessed using a self-reported visual analog scale (VAS). Other outcomes as operation time, blood loss, and hospital stay were also analyzed. Results: Nine patients (five males and four females) were included in this study. The mean ± SD age was 24 ± 2.96 years. Compared with preoperative data, the LBP-VAS has significantly decreased (p < 0.001) after one day (5.67 ± 0.87), after three months (3.67 ± 0.5), after six months (2.78 ± 0.44), and after one year (1.67 ± 0.5). Leg pain VAS has been reduced to 3.11 ± 1.05 on the first postoperative day, 1.44 ± 1.59 after three months, 0.56 ± 0.53 after six months, and 0.11 ± 0.33 after one year. The mean operative time was 120 ± 37.1 minutes, blood loss was 325.56 ± 53.18 ml., and hospital stay was 5.22 ± 1.2 days. Conclusion: After 12 months of follow-up, surgical repair and preservation of the spine motion are possible with excellent outcomes in patients with two or three-level spondylolysis. Keywords: Spondylolysis, Surgical repair, fusion, spine, orthopedics. Juan Jose Ramirez Minor 1 1 Universidad de Monterrey, Cirugia de Columna, Monterrey, Mexico Objective: Evaluate the functional outcomes of treating degenerative spondylolisthesis with lumbar stenosis through Posterior Lumbar Interbody Fusion (PLIF) using transpedicular screws and to compare this with PLIF using interspinous spacers. Methods: Observational, cross-sectional, retrospective study. Functional results of treating lumbar degenerative spondylolisthesis with lumbar stenosis are presented. Two groups were identified: Group 1 received posterior lumbar interbody fusion with transpedicular screws, and Group 2 received posterior lumbar interbody fusion with interspinous spacers. Demographic and surgical variables, the Visual Analog Scale (VAS), and the Oswestry Disability Index (ODI) were compared. Results: A total of 43 patients were included, with 22 in Group 1 and 21 in Group 2. The average age was 59.7 years (SD 12.728). In Group 1, the pre-surgical ODI score averaged 67.5% (SD 10.707) and the post-surgical score at 12 months averaged 19.18% with p = 0.874. The pre-surgical VAS score averaged 8.36 (SD 0.790) and the post-surgical score at 12 months averaged 2.68 with p = 0.778. Group 2 showed a pre-surgical ODI score averaging 68.05% (SD 11.826) and post-surgical at 12 months averaging 19.52% with p = 0.357. The pre-surgical VAS score averaged 8.43 (SD 0.978), and at 12 months post-surgery averaged 2.67, with p = 0.467. In Group 1, there were no late post-surgical complications, while Group 2 reported 2 cases of deep tissue infection and 1 case of interbody cage subsidence. Conclusions: The treatment of lumbar degenerative spondylolisthesis with lumbar stenosis with posterior release and fusion using interspinous spacers presents functional outcomes that do not show significant differences compared to fusion with screws, but with a higher number of complications. Keywords: Lumbar spondylolisthesis, Lumbar stenosis, PLIF, Fusion spacer, Disability, Pain. Sami Bahroun 1 , Jhimi Ali 1 , Mohamed Samih Kacem 1 , Anis Bouaziz 1 , Ammar Ameni 1 , Mohamed Samir Daghfous 1 1 Kassab Institute of Orthopaedics, Orthopaedics Department B, Ksar Said, Tunisia Introduction: Obesity is a common comorbidity among spine patients. Previous studies that have investigated correlations between obesity and complications in thoracolumbar spine surgery found mitigated results. The impact of obesity on complications, operative time, and length of hospitalization remains uncertain in this population. The purpose of this study was to investigate the correlation between obesity, complications, length of stay, and operative time following posterior lumbar fusions for degenerative lumbar conditions. Material and Methods: Patients undergoing posterior lumbar fusions were evaluated from 2020 to 2023. Follow-up of at least 12 months was required. Patients were excluded in cases of trauma, tumor, infection, urgent/emergent surgery, deformity, fusions that involved non-lumbar levels (sacral or thoracic) and pseudarthrosis. Complications assessed included wound infection, hematoma, urinary tract infection, deep venous thrombosis, pulmonary embolism, pneumonia, myocardial infarction, death, or new neurologic deficit. Patients were defined as “obese” for BMI greater than or equal to 35 based on the World Health Organization (WHO) definition. Chi-square and student-t tests were used to analyze demographic and surgical characteristic. Complications were retrospectively noted from the medical records. Complication rates in each group were compared using Chi-Square analysis. Results: A total of 124 patients were included with 90 (73%) BMI ≤ 35, and 34 (27%) with BMI > 35. The overall 90-day complication rate was 6.5%. There was a no statistical difference in complications between groups: BMI ≤ 35 had 7 (6.2%) complications, compared with 9 (7.2%) in the BMI > 35 group (p = 0.38). surgical site infection was the most common complication (5 incidents in each group); others included hematoma, urinary tract infection, deep venous thrombosis, and appearance of a new neurologic deficit. Length of stay was lower in the BMI ≤ 35 group (1.5 vs 2.1 days, p = 0.031). There was no significant difference in operative time (170 vs. 183 minutes, p = 0.11). Conclusion: In this analysis of data from patients undergoing fusion surgery for degenerative lumbar disorders, BMI greater than 35 was not associated with increased 90-day complications or of operative time. Length of stay was found to be slightly longer in the obese group. These findings suggest that although it might be limited, obesity does have an impact on the quality of treatment for such a condition. Sami Bahroun 1 , Jhimi Ali 1 , Mohamed Samih Kacem 1 , Alaa Aloui 1 , Ammar Ameni 1 , Mohamed Samir Daghfous 1 1 Kassab Institute of Orthopaedics, Orthopaedics Department B, Ksar Said, Tunisia Introduction: Diabetes mellitus is recognized as one of the most widespread chronic diseases that increases complications in multiple orthopaedic surgeries. For instance, in patients undergoing degenerative spine surgery, it has been correlated to increased complications and reoperations. The impact of objective glycemic markers on predicting these complications is still unclear. This study aims to describe the effect of glycated hemoglobin (HbA1c) levels on complications in diabetic patients undergoing lumbar spine surgery for degenerative disorders. Material and Methods: Patients with type 2 diabetes who underwent lumbar spine surgeries for degenerative disorders were retrospectively reviewed between June 2019 and June 2023. A total of 112 patients were initially selected, and the last HbA1c levels before the surgery were noted. Patients were grouped into two different groups based on their HbA1c levels: group 1 with HbA1c levels from 5 to 6.5%, group 2 from 6.6% and above . Patients with no HbA1c levels in the 04 weeks previous to the operation or had missing data were excluded. A total of 82 patients were finally selected. Demographic information, intraoperative and postoperative complications were collected and analyzed to determine the relationship between HbA1c levels and postoperative complications for up to 6 months after discharge. We conducted a univariate statistical analysis to determine if the HbA1c levels had a statistical impact on the risk of complications. Results: Group1 was made of 46 patients, group2 of 36. Group1 had one patient that suffered from a urinary tract infection and one other of localized hematoma, for a total of 2 postoperative complications. Group 2 had 2 patients that developed hematomas, 03 site infection, 02 urinary tract infections, and one patient presented with a deep vein thrombosis that later developed into a pulmonary embolism. No patients had respiratory nor neurological complications after the surgery. No revision surgeries took place for group1, meanwhile a total of 6 patients in the second group: in majority for site infections (50%), 05 of which were undergone in the 03 first weeks following the surgery. Only one patient (from group 3) had a revision surgery after the 03 first postoperative weeks for experiencing interbody spacer migration in 3 to 4 months postoperative period. Finally, our statistical analysis determined that HbA1c levels were a significant risk factor for developing postoperative complications (p < 0.05). Conclusion: The use of preoperative HbA1c as a predictor of outcomes for surgical patients has been controversial. In our study HbA1c levels did correlate with the incidence of complications during various postoperative periods. HbA1c should be regarded and used as a predictor of postoperative adverse effects and complications. José Spirig 1 , Alexandra Grob 1 , Nadja Farshad 1 , Mazda Farshad 1 1 Balgrist University Hospital Zurich, Zurich, Switzerland Introduction: Dorsal spinal instrumentation with transpedicular screws, considered the gold standard for numerous spinal pathologies, can still be challenging in osteoporotic bone due to the risk of screw misplacement or pullout, which can lead to severe complications. The Cortical Bone Trajectory (CBT) technique optimizes screw placement to maximize contact with dense cortical bone, thereby enhancing stability. The aim of this study was to evaluate the accuracy of patient-specific template-guided CBT pedicle screw placement in the lumbar spine compared to the conventional freehand technique using fluoroscopy. Material and Methods: This single-center randomized controlled trial (RCT) randomized patients into two groups between 2017 and 2022 for elective thoracolumbar spinal fusion (Th12-L5): patient-specific targeting CBT-guided technique (CBTT) and conventional freehand technique (CFT). The primary outcome, screw placement accuracy, was evaluated using computed tomography (CT) according to the Laine classification. Secondary outcomes included intervention time, estimated blood loss, radiation dose, screw fracture/loosening, skin incision length, reoperation rate, functional and clinical outcomes (Oswestry Disability Index and pain), and muscle atrophy. Results: Thirty-four patients were randomized into the CFT group and thirty-three into the CBT group, with four segments affected in each group. In both groups, the majority had fusion of only one segment (91% in CFT and 97% in CBT). The main symptom in the CFT group was claudication (26%), while lumbar pain predominated in the CBT group (24%). Laine classification showed similar screw placement with a higher rate of lateral or ventral perforation > 1 mm in the CBT group (14 vs 8). Skin incision length was significantly shorter in the CBT group (9.5 cm vs. 12 cm, p = 0.002), and radiation dose was significantly lower (416 vs. 735 mGy·cm 2 , p = 0.013). No differences were observed in instrumentation time, estimated blood loss, length of hospital stay, or muscle atrophy after 6 months. No significant differences between groups in terms of postoperative ODI, back or leg pain. One pedicle fracture occurred in each group, while one infection was reported in the CFT group and three in the CBT group, requiring surgical revision. Conclusion: The patient-specific targeting CBT-guided group demonstrated decreased radiation exposure, shorter skin incision length, and similar functional outcomes after 2 years compared to the conventional freehand technique. Iqra Yasin 1 , Rida Yasin 2 , Waleed Yasin 2 , Mohammad Yasin 2 1 Queen Elizabeth Hospital, Neurosurgery, Birmingham, United Kingdom , 2 Bahawal Victoria Hospital and Aleena Hospital Bahawalpur, Department of Neurosurgery, Bahawalpur, Pakistan Introduction: Lumbar spinal stenosis is a condition caused by narrowing of the lumbar spinal canal from hypertrophy of facets, ligamentum flavum, and/or bulging intervertebral discs. Decompression of these neural structures by means of laminectomy has increasingly been supplemented with lumbar fusion, with the intention of minimising a potential risk of future instability and deformity. However significant controversy exists regarding the role of instrumented fusion as its outcomes have not been substantiated in comparative studies. This randomised controlled trial aims to compare outcomes of laminectomy alone versus laminectomy with fusion for the treatment of lumbar spinal stenosis (LSS) with spondylolisthesis. Material and Methods: A multicentric RCT was performed enrolling 84 consecutive patients with grade 1-2 degenerative lumbar spondylolisthesis and symptomatic spinal stenosis. Patient demographics including age, gender, BMI, medical history and physical examination were noted. Patients were randomized with 1:1 ratio into two groups. Group A (containing 42 patients) were treated with laminectomy and instrumented fusion using pedicle screws and titanium alloy rods across the level of listhesis. Group B (containing 42 patients) underwent decompression alone. Patients were blinded to the intervention received. Primary outcome measures were post-operative hospital stay, readmission, operative time and Oswestry Disability Index (ODI). Patients were followed up at 2 weeks, 3, and 6 months to assess their ODI scores. Results: Mean age of patients included in this study was 62.83 ± 6.16 years. There were 19 (22.6%) male patients and 65 (77.4%) female patients. Both groups were comparable in terms of demographics. All patients were followed up till 6 months. Mean ODI in Group A (laminectomy plus fusion) was 22.14 ± 4.89 and group B (laminectomy alone) was 30.50 ± 12.24 p-value < 0.001. Hospital stay was longer in group A (3.34 ± .77 days) compared to group B (2.55 ± 0.7) p-value < 0.001. The operative time was longer for group A (220.33 ± 17.27 min) as compared to group B (146 ± 16.5 min) p-value < 0.001. There were 6 (8.3%) patients who underwent reoperation on 2nd post-operative day. Two out of six had hematoma with wound infection and the rest four had CSF leak in group A. There was no significant neurological deficit. Conclusion: Our findings suggest that lumbar laminectomy with instrumented fusion is more effective than laminectomy alone at improving functional impairment (ODI scores) in patients with LSS but at the expense of longer hospital stay and operative time. These results warrant confirmation in larger prospective comparative studies over a longer follow-up. Hannah Van Brenk 1,2 , Erin Bigney 2,3 , Neil Manson 2,4,5,6 , Chris Small 2,4,6,7 , Edward Abraham 2,4,6,8 , Najmedden Attabib 2,5,9 , Jill Kearney 2,3 , Eden Richardson 2,3,10 , Jeffrey Hebert 11,12 1 University of New Brunswick, Fredericton, Canada , 2 Canada East Spine Centre, Saint John, Canada , 3 Horizon Health Network, Saint John, Canada , 4 Horizon Health Network, Division of Orthopaedic Surgery, Zone 2, Saint John, Canada , 5 Dalhousie University , Faculty of Medicine, Halifax, Canada , 6 Saint John Orthopaedics, Saint John, Canada , 7 Dalhousie Medicine New Brunswick, Saint John, Canada , 8 Dalhousie Medicine New Brunswick, Department of Surgery, Saint John, Canada , 9 Horizon Health Network, Division of Neurosurgery, Zone 2, Saint John, Canada , 10 Canadian Spine Outcomes and Research Network, Markham, Canada , 11 University of New Brunswick, Faculty of Kinesiology, Fredericton, Canada , 12 Murdoch University, School of Psychology and Exercise Science, Perth, Canada Background: Recent research has demonstrated preoperative psychological health significantly effects postoperative outcomes in patients undergoing surgery for cervical spondylotic radiculopathy. However, the impact of preoperative psychological health on outcomes for patients undergoing discectomy for lumbar radiculopathy resulting from disc herniation remains unexplored. Objective: This study aims to estimate the effects of preoperative psychological factors on postoperative pain and disability measures in patients undergoing discectomy for lumbar radiculopathy. Methods: This retrospective cohort study utilized data from patients enrolled in the Canadian Spine Outcomes and Research Network registry who underwent discectomy for lumbar radiculopathy caused by disc herniation. Preoperative psychological measures included the Patient Health Questionnaire-8 (PHQ-8) and the Mental Component Summary Score (MCS) of the Short Form Survey-12. For the PHQ-8, a score ≥ 10 indicates moderate-to-severe depression risk, while MCS scores < 46 indicate depression, and scores < 37 indicate severe psychological symptomology. Clinical outcomes of interest were the numeric rating scale (NRS) for back pain, NRS-leg pain, and the modified Oswestry Disability Index (ODI) collected preoperatively and at 3-, 12- and 24-months post-surgery. Confounding variables controlled for were age, sex, highest level of education attained, current smoking status, baseline physical functioning, and surgical wait time. Recovery trajectories for leg pain and overall recovery (including leg pain, back pain and disability) were identified with latent class growth models. Doubly Robust estimates of the average treatment effects were constructed with exposure (inverse probability weighting) and outcome (regression) models. Results were reported with risk ratios (RR). Sensitivity analysis assessed potential bias from extreme weights and unmeasured confounding. Results: Data from 1,104 patients (52% female; mean age = 43.90 years) were included. The leg pain recovery trajectory identified 11.4% of patients who experienced a “poor” outcome, while 28% of patients had “poor” overall recovery. Over half (60%) of patients were at moderate-to-severe risk of depression. Moderate-to-severe depression risk increased risk of poor leg pain recovery (RR [95% CI] = 1.61 [1.07 to 2.43]) and poor overall recovery (RR [95% CI] = 1.90 [1.46 to 2.4]). Similarly, 57% of patients experienced preoperative depression, which increased risk of poor leg recovery (RR [95% CI] = 1.92 [1.20 to 3.08]) and overall recovery (RR [95% CI] = 2.07 [1.51 to 2.86]). Finally, 30% of patients scores indicated severe psychological symptomology increasing their risk of poor leg recovery (RR [95% CI] = 1.78 [1.21 to 2.61] and poor overall recovery (RR [95% CI] = 1.93 [1.55 to 2.40]). Sensitivity analysis showed that substantial unmeasured confounding would be needed to explain away the observed effects. Conclusions: Most patients undergoing discectomy for lumbar radiculopathy exhibit signs of poor psychological health before surgery which adversely impacts surgical outcomes. These findings, suggest that targeting preoperative psychological health could be an avenue to optimize surgical outcomes for patients undergoing discectomy for lumbar radiculopathy resulting from disc herniation. Joshua Bruce 1 , Aakash Shah 1 , Seth Meade 1 , Ghaith Habboub 2 , Michael Steinmetz 2 , Mohamed Macki 2 1 Center for Spine Health, Cleveland Clinic Foundation, Cleveland, United States , 2 Center for Spine Health, Cleveland Clinic Foundation, Department of Neurosurgery, Cleveland, United States Introduction: Transforaminal lumbar interbody fusion (TLIF) is a surgical procedure used to treat spinal instability, radiculopathy, and degenerative disc diseases. These operations involve a facetectomy, a removal of the facet joint, which can be performed unilaterally or bilaterally depending on the patient’s pathology. This study investigates whether there is a difference in patient satisfaction, as measured by Hospital Consumer Assessment of Healthcare Providers Systems (HCAHPS) survey, between unilateral and bilateral facetectomy. Materials and Methods: One- and two-level TLIF procedures at a tertiary academic center were retrospectively reviewed for unilateral or bilateral facetectomies between 04/2016 and 12/2023. Variables collected included demographic, clinical, and surgical data. Patient satisfaction was measured by collecting HCAPHS scores which includes various domains such as communication, pain management, and overall rating of care. When comparing the outcomes between the study groups, continuous variables were examined using a t- test. Categorical variables were analyzed using chi-square tests. Logistic modeling was used for multivariable regression. Results: There were 71 unilateral facetectomy TLIF and 143 bilateral facetectomy TLIF patients in the cohort. The average follow-up in the unilateral and bilateral cohorts was 25.8 and 21.0, months, respectively. There were no statistically significant demographic differences with respect to age, sex, BMI, smoking history, average follow-up time, race, or ethnic group between groups. There was no difference in operative time, length of stay, number of levels fused, or number of levels decompressed between groups. Open operations were more likely to undergo a bilateral facetectomy (116 vs 41 cases), while minimally-invasive operations were likely to include a unilateral facetectomy (30 vs 27). (p ≤ 0.001). The bilateral cohort was more likely to suffer from postoperative infections, instrument failure, DVT within 3 months, revision surgery, and 90-day readmission or ED visits (p ≤ 0.001). The unilateral cohort was more likely to suffer from future surgery on a different spinal level (p ≤ 0.001). There was no difference in HCAPHS outcomes for “Overall Health” or “Mental Health” between the cohorts. Bilateral facetectomy was associated with worse “Overall” Health” and improved “Mental Health” scores; however, this was not statistically significant. An increased BMI and active smoking status was associated with poorer “Overall Health” scores (p = 0.018) and “Mental Health” scores (p = 0.030), respectively. Conclusion: TLIF procedures with unilateral versus bilateral facetectomies have similar HCAPHS outcomes; however, bilateral cohort incurred significantly increased postoperative complications. Surgical consent discussions should weigh the benefit of the bilateral facetectomy with the increased surgical risks. Juan Pablo Taleb 1 , Ruy Lloyd 2 , Matias Leonardo Cullari 2 , Lucio Gutierrez 2 1 Hospital Universitario Austral, Servicio de Columna, Pilar, Argentina , 2 Hospital Británico de Buenos Aires, Caba, Argentina Introduction: Spinal arthrodesis has proven to be an effective method for treating degenerative lumbar disorders. Percutaneous instrumentation offers an alternative to conventional open surgery, aiming to reduce soft tissue damage. Material and Methods: This was a prospective cohort study with a one-year follow-up. Thirty-three patients underwent intersomatic arthrodesis (ALIF, OLIF, XLIF) combined with percutaneous posterior instrumentation for degenerative lumbar disorders between June 2021 and June 2022. Inclusion criteria: Degenerative lumbar disorders (spondylolisthesis, discopathies, scoliosis < 20°), severe lumbar and/or lower limb pain without neurological deficits, and a minimum clinical and radiological follow-up of 12 months. Exclusion criteria: Oncological pathologies, fractures, open surgeries (conventional posterior approach), and follow-up shorter than 12 months. This study was approved by the ethics committee, and all patients signed informed consent forms allowing the use of their data. Clinical variables: Age, sex, complications, Oswestry Disability Index (ODI) values, and visual analog pain scale scores were recorded preoperatively, at 6 months, and at 12 months postoperatively. Radiological variables: total lumbar lordosis (L1-S1) and segmental lordosis (L4-S1) pre and postoperatively; disc height of the treated space; reduction of listhesis; foraminal height; Hounsfield units of the bodies of the five lumbar vertebrae and both pedicles before surgery; and degree of consolidation one year after surgery. Allograft-filled PEEK devices and titanium screws and rods were utilized. Results: The mean age of patients was 58.9 ± 13.7 years. A follow-up at 12 months revealed complications in 4 patients (12.1%): 5 vertebral fractures. 4 occurred during surgery (1 subsidence of 2 levels, 2 of 1 level) and 1 occurred spontaneously 10 days post-surgery. Bone density values (Hounsfield units) indicated that most patients had osteoporosis or osteopenia. No infections were reported in any patient. At 6 and 12 months, there was a significant decrease in median ODI compared to preoperative values (12; IQR 25-75%: 2.5-22 and 6; IQR 25-75%: 0.17 vs 38; IQR 25-75%: 34.5-56 respectively; p < 0.0001). Similarly, significant decreases were observed in lumbar VAS (2; IQR 25-75%: 0-5 and 1; IQR 25-75%: 0-2.7 vs 9.5; IQR 25-75%: 8-10 respectively; p < 0.0001) and for lower limb VAS (1; IQR 25-75%: 0.4 and 1; IQR 25-75%: 0-3 vs 9; IQR 25-75%: 8-10 respectively; p < 0.001). A significant increase in the height of the L4-L5 space was observed compared to pre-surgery values (13.7 ± 3.7 vs 9.8 ± 3.8 mm; p < 0.001), as well as at L5-S1 (9.2 ± 3.7 vs 11.8 ± 4.2; p < 0.05), and foraminal height at L4-L5 (16.3 ± 2.9 vs 19.3 ± 2.7; p < 0.001). Consolidation at one year showed that 17 (51.5%) patients had evidence of intersomatic and facet level bridging; 10 (30.3%) had only intersomatic bridges; 3 had facet level bridges (9.1 %); and 3 patients showed no evidence of consolidation (9.1 %). Conclusion: The anterior/lateral approach using allograft-filled PEEK devices, combined with percutaneous instrumentation, represents a safe technique for treating degenerative lumbar disorders. It yields good clinical and radiological outcomes and can be standardized for reproducibility in other centers. Kaike Eduardo Da Silva Lobo 1 , Paweł Łajczak 2 , Cláudia Santos 3 , Rafael Oliveira 4 , Ramon Guerra Barbosa 5 , Yan Silva 6 1 State University of Pará, Belém, Brazil , 2 Medical University of Silesia, Katowice, Poland , 3 FG University Center, Brumado, Brazil , 4 Federal University of Pará, Belém, Brazil , 5 Clínica Medular, Department of Spine Endoscopy, Montes Claros, Brazil , 6 Hospital Ortopédico do Estado, Salvador, Brazil Introduction: Lumbar spinal stenosis (LSS) is a common spinal degenerative disease. In recent years, both uniportal and biportal endoscopic decompression techniques have gained attention, demonstrating safety and promising clinical outcomes. However, there remains no consensus on the optimal endoscopic approach. This systematic review and updated meta-analysis aimed to evaluate the outcomes of both approaches for managing LSS. Material and Methods: We systematically searched PubMed, Embase, Cochrane Library, and Web of Science for randomized controlled trials and observational studies comparing uniportal and biportal decompression techniques for patients with LSS. The outcomes assessed included intraoperative blood loss, length of hospitalization, operative time, Visual Analog Scale (VAS) scores for leg and back pain, Oswestry Disability Index (ODI), MacNab criteria excellent or good rate, and postoperative complication rate. Mean difference (MD) and odds ratio (OR) were calculated for continuous and binary outcomes, respectively, with 95% confidence interval (CI). Results: Of 80 articles screened, 8 studies were included, comprising 927 patients, of whom 464 underwent uniportal and 463 biportal decompression. No significant differences were found between groups in intraoperative blood loss (MD -2.66; 95% CI -9.18, 3.86; p = 0.42; I 2 = 99%), length of hospitalization (MD 0.02; 95% CI -0.23, 0.27; p = 0.87; I 2 = 43%), complication rate (OR 1.18; 95% CI 0.60, 2.72; p = 0.527; I 2 = 0%), and MacNab criteria excellent or good rate (OR 0.68; 95% CI 0.22, 2.14; p = 0.511; I 2 = 64%). However, operative time was significantly longer in the uniportal group (MD 21.77; 95% CI 6.73, 36.80; p < 0.01; I 2 = 100%). No significant differences were observed in ODI at 3 months (MD 3.81; 95% CI -2.74, 10.36; p = 0.25; I 2 = 99%), 6 months (MD 7.84; 95% CI -3.74, 19.43; p = 0.18; I 2 = 100%), or 12 months (MD 0.78; 95% CI -0.11, 1.67; p = 0.09; I 2 = 0%). VAS leg pain scores were similar at 3 months (MD 0.12; 95% CI -0.05, 0.30; p = 0.17; I 2 = 39%), 6 months (MD 0.11; 95% CI -0.06, 0.29; p = 0.21; I 2 = 40%), and 12 months (MD 0.11; 95% CI -0.18, 0.40; p = 0.47; I 2 = 70%). Similarly, VAS back pain scores showed no significant differences at 3 months (MD -0.05; 95% CI -0.22, 0.12; p = 0.55; I 2 = 37%), 6 months (MD 0.05; 95% CI -0.13, 0.24; p = 0.58; I 2 = 44%), or 12 months (MD 0.09; 95% CI -0.02, 0.20; p = 0.10; I 2 = 0%). Conclusion: This meta-analysis demonstrated that the biportal technique had a significantly shorter operative time than the uniportal approach. However, there were no significant differences between the two methods in terms of intraoperative blood loss, length of hospitalization, complication rates, or patient outcomes related to pain and function. Given the retrospective nature of most of the included studies and the influence of single-surgeon operations on surgical time, further high-quality studies are needed to clarify the reasons for the longer operative time in the uniportal approach and better assess the advantages of both techniques for LSS treatment. Edwin Fernando Pesantez Mochas 1 , Alejandro Reyes-Sánchez 1 , Baron Zarate-Kalfopulos 1 , Carla García-Ramos 1 , Omar Irving 1 1 Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Spine Surgery Division, Mexico City, Mexico Introduction: Degenerative spondylolisthesis, characterized by the forward slippage of one vertebra over another, is a common cause of spinal instability and low back pain. Accurate preoperative assessment of spinal alignment and slippage is crucial for planning surgical interventions. This study aims to evaluate the correlation between slip and lumbar sagittal parameters using preoperative upright X-rays and supine MRI, two commonly employed imaging modalities. By analyzing these parameters, the goal is to determine whether preoperative imaging findings predict postoperative radiographic outcomes, providing valuable insights for optimizing surgical approaches and improving patient outcomes in degenerative spondylolisthesis cases. Material and Methods: Retrospective study of radiographic, supine MRI, and operative records of patients who underwent primary open decompression and fusion for degenerative spondylolisthesis from January 2018 to December 2020 with a minimum follow-up of 24 months. Radiographic measurements were taken preoperatively, intraoperatively, and postoperatively at 6, 18, and 24 months. Additionally, functional clinical scales were assessed both pre- and postoperatively to evaluate patient outcomes. Results: A total of 108 lumbar procedures were performed in 79 patients. The mean age was 62.76 (±12.08) years, 58 (73.4%) were female. No difference in vertebral slip using preoperative MRI and upright neutral radiographs at each measurement during the follow up: 3.09 ± 3.24 mm (10.52% ± 8.52) of the MRI vs 2.06 ± 2.27 (4.90% ±4.73), 2.86 ± 2.31 (5.32% ±4.22), 3.33 ± 2.25 (6.86% ±5.03), and 3.79 ± 2.28 (7.02% ±5.28) at the immediate postoperative, at 6, 12 and 24 months of follow up. Correlations were made between preoperative spondylolisthesis on MRI and postoperative radiographs at various evaluations, yielding a value of r = 0.277, p = 0.005, indicating a correlation between these variables. Conclusion: The use of upright neutral lateral X-rays combined with supine MRI provides a more accurate identification of spinal instability. Preoperative MRI measurements did not significantly differ from radiographic outcomes at the final follow-up in postoperative patients. The quantification of changes between upright X-rays and supine MRI positively correlated with the reduction in slip, segmental lumbar lordosis (SLL), and total lumbar lordosis (TLL) at the end of follow-up. Finally, clinical improvement in patients who underwent surgery correlated with enhanced outcomes in functional clinical scales. Faiz Ahmad 1 , James Malcolm 1 1 Emory University, Atlanta, United States Background: High-grade spondylolisthesis at L5-S1 is difficult to treat due to the forces at play. Several surgical options have been described including posterior, anterior, and circumferential, with optional reduction, and techniques have evolved along with implant technology; however, no clear approach is superior. The threaded Rialto fenestrated cage was introduced for sacroiliac joint fusion but may be a robust alternative for trans-sacral fixation with a fibular strut or bolt. Methods: Retrospective case series of patients treated by posterior alone with the Medtronic Rialto case for trans-sacral fixation spanning the L5-S1 disc space. Data was collected on preoperative and postoperative lumbosacral parameters, follow up, fusion rate, and complications. Results: 12 patients underwent the procedure (9 female, 3 males, average age 54 ± 12 yrs) between 2014 and 2024. Spondylolisthesis was a grade 2 in three cases, grade 3 in seven cases, and grade 4 in two cases. All patients had at least one outpatient follow up visit, with overall follow-up ranging from 4mo to 4.8 yrs. No patient had evidence of non-union or complication in any follow up imaging. All patients experienced either complete or partial resolution of pain, with no worsening of symptoms. One patient had a superficial dehiscence requiring washout. Conclusion: The Rialto fenestrated screw provides robust trans-sacral fixation with easy delivery. Râmi Lorandi 1 , Alisson R. Teles 2 , Guilherme Ludwig 2 1 Universidade de Caxias do Sul, School of Medicine, Caxias do Sul, Brazil , 2 Hospital São José - Santa Casa de Porto Alegre, Neurosurgery, Porto Alegre, Brazil Introduction: Chronic low back pain is a public health problem in Brazil. Despite the widespread use, the effectiveness of facet and epidural injections is unclear in the literature. No study has assessed the efficacy of these procedures in the Brazilian Public Healthcare System. Material and Methods: Prospective study with patients selected for injections in a single spine center in Southern Brazil from January 2020 to April 2022. All patients underwent a standard protocol of facet joint (3 or more levels) and epidural (caudal) injections with methylprednisolone and ropivacaine. Patient reported outcomes (numerical rating scale/NRS for back and leg pain, Oswestry disability index/ODI, EQ5D) were collected before the procedure and at the 4 weeks follow-up with a standard protocol. Paired analyses were performed with SPSS. Results: During the study period, 80 patients underwent lumbar spine injections, 77 filled out the baseline protocol and 65 patients returned to the 4-week follow-up (15.5% loss of follow-up) and were included in the final analysis. The mean reduction in NRS back pain was 2.16 (+-3.22, p < 0.001) and NRS leg pain 1.40 (+-3.34, p = 0.001). In general, there was no statistically significant difference in disability (ODI) or general health quality of life (EQ5D) after the procedure. Overall, 47.7% were satisfied, 56.9% reported feeling better and 69.2% would do the same procedure again. In general, greater reductions in back and leg pain as well as improvements in disability and quality of life were statistically associated with satisfaction, self-reported improvement and willingness to repeat the procedure. No association between baseline variables and post-injection results were identified. Regarding patient expectations, 51.6% reported that the procedure provided partial or complete relief of back and 59.7% for leg pain, 62.3% reported improvement in performance of daily activities, 55.7% for walking capacity, and 59% for mental well-being. The prevalence of opioid use at 4 weeks follow-up was 24.2%, compared to 37.1% at baseline (p = 0.035). Conclusion: Facet joint and epidural injections provide small/modest back and leg pain relief at short-term in patients with chronic back pain treated in the Brazilian Public Healthcare System. From a health economic perspective, the value of such procedures is unclear in this healthcare system. Joseph Maalouly 1 , Prashanth Rao 1,2,3,3,4 1 Brain and Spine Surgery, Bella Vista, Australia , 2 Norwest Private Hospital, Department of Neurosurgery, Bella Vista, Australia , 3 University of New South Wales, Sydney, Australia , 4 Macquarie University Hospital, Department of Neurosurgery, Macquarie Park, Australia Introduction: Sacroiliac (SI) joint dysfunction is a common source of back pain. Recent evidence from different parts of the world suggest that cooled radiofrequency ablation of sacral nerves supplying the SI joints has superior pain alleviating properties than currently available treatment options for SI joint dysfunction. Material and Methods: After obtaining institutional review board approval, the medical records of 170 patients who underwent cooled radiofrequency ablation in a single institution and by a single surgeon were analyzed retrospectively. The recurrence of pain, progression to fusion and functional outcomes were noted. The patients were operated on between June 2020 and May 2023, they include 109 females and 61 males, the average age was 56.8 ± 16.6. Follow up was at least 6 months postop. Results: 45 of the patients had previously underwent lumbar fusions. Follow up period ranged from 6 to 24 months. After radiofrequency ablation, 28 patients progressed to fusions, and 17 patients had to have the procedure done again to relieve their pain. Student t-test was used to compare between preop and postop values of NPRS (numerical pain rating score) and ODI (Oswestry disability index). It showed significance with p-value < 0.01 in both at 3, 6, 12 months postoperatively. RMQ (Roland Morris score) student t-test was significant with p value < 0.01 at 3 months between preoperative and postoperative values; however, at 6 months and 12 months they were not significant. Conclusion: Sacroiliac joint radiofrequency ablation is a good option in the treatment of SI joint pain showing good results in the short term follow up period. It is a simple procedure that can be done in less than 30 minutes and can provide significant pain relief for patients with sacroiliac joint dysfunction.

Oleksii Nekhlopochyn 1 , Vadim Verbov 1 , Svitlana Verbovska 1 , Ievgen Cheshuk 1 1 Romodanov Neurosurgery Institute, Spine Neurosurgery, Kyiv, Ukraine Introduction: Traumatic spinal injuries represent a significant medical and social challenge, due to the substantial costs associated with both acute medical management and the prolonged, resource-intensive rehabilitation required. The thoracolumbar junction (TLJ) is particularly susceptible to injury due to its unique biomechanical properties. However, the reported frequency of TLJ injuries in the literature is inconsistent. This study aims to evaluate the proportion of TLJ fractures within the overall spectrum of traumatic spinal injuries in the adult population. Material and Methods: A meta-analysis was performed by systematically searching the MEDLINE database using MeSH terms and keywords in titles and abstracts to identify studies meeting predefined inclusion criteria. The search yielded 22 full-length articles. Data extraction and analysis were conducted independently by two experts. Results: The analysis revealed that TLJ fractures constitute 46.51% (95% confidence interval [CI]: 36.76 - 56.27%) of all spinal injuries. Specifically, fractures were distributed as follows: Th11 - 4.26% (95% CI: 3.35 - 5.17%), Th12 - 13.98% (95% CI: 10.41 - 17.56%), L1 ‒ 22.21% (95% CI: 17.66 - 26.76%), and L2 - 9.69% (95% CI: 6.82 - 12.57%). Within the thoracolumbar region, TLJ injuries accounted for 61.88% (95% CI: 52.53 - 71.22%). Fracture distribution within the TLJ was as follows: Th11 - 10.2% (95% CI: 8.05 - 12.36%), Th12 - 26.56% (95% CI: 22.42 - 30.7%), L1 - 42.76% (95% CI: 39.7 - 45.81%), and L2 - 20.48% (95% CI: 16.73 - 24.23%). Conclusion: This meta-analysis provides robust, quantitative data on the distribution of TLJ fractures within the broader context of traumatic spinal injuries. To the best of our knowledge, this is the first study to present such detailed findings derived from a meta-analytic approach. Steven Roth 1 , Fthimnir Hassan 2 , Erik Lewerenz 2 , Nathan Lee 3 , Chun Wai Hung 4 , Justin Scheer 5 , Joseph Lombardi 2 , Zeeshan Sardar 2 , Ronald A. Lehman 2 , Lawrence Lenke 2 1 University of Florida Medical Center, Gainesville, United States , 2 Columbia University Irving Medical Center, New York, United States , 3 Midwest Orthopaedics at RUSH, Chicago, United States , 4 Houston Methodist, Houston, United States , 5 Cedar Sinai Medical Center, Los Angeles, United States Introduction: Revision surgery among adult spinal deformity (ASD) patients remains less well-studied than index ASD operations. We sought to characterize indications as well as assess patient reported outcomes measures (PROMs) and long-term complication rates in this patient population. We hypothesize that these patients will experience significant improvements in both radiographic alignment and PROMs. Methods: A retrospective review of a prospectively collected, single-center database was performed to identify ASD patients undergoing revision surgery with a minimum of 2 year follow-up. Patient demographic, radiographic, operative/perioperative, long-term complications, and PROMs, specifically the Scoliosis Research Society-22r (SRS-22r) and the Oswestry Disability Index (ODI), data were collected and analyzed. The outcomes of interest included the long term-complication rate, overall reoperation rate, and change in PROMs and their respective domains. Results: 149 patients were identified with a mean age of 50.3 ± 17.2 yrs, 2.4 ± 3.2 prior spine surgeries, and 68.5% (n = 102) being female. Patients had a mean number of 3.3 ± 1.4 indications for revision when presented at preop. We found that the most common indication for revision surgery to be overall malalignment (74%), followed by pseudarthrosis (40%), lumbar stenosis (33%), and implant failure (24%). The number of total instrumented levels (TIL) increased from 9.6 ± 5.3 at baseline to 14.9 ± 5.1 following revision (p < 0.0001), with 77% (n = 114) of patients having changes made to the upper instrumented vertebrae (UIV), 54% (n = 81) with changes to the lower instrumented vertebrae (LIV), and 28% (n = 42) undergoing 3-column osteotomies (3COs). Of the patients with changes to the LIV, 80% (n = 65) were extended to the pelvis. Pts saw significant changes across all radiographic parameters aside from thoracic kyphosis (preop: 41.4 ± 23.8 vs postop: 40.5 ± 11.7, p = 0.6022). Mean length of stay (LOS) was 8.0 ± 14.5 days with 22% (n = 33) being discharged to a rehab facility. 49% (n = 73) of pts experienced at least one complication following discharge for a total of 135 complications. We found the most common postoperative complication to be implant failure and pseudarthrosis (18%) followed by PJK (11%). 34% (n = 51) of patients returned to the OR following the initial revision for a total of 66 additional surgeries. Despite this, significant improvements were seen all domains of the SRS-22r and ODI were observed with 74%, 51%, 71%, 68%, 41%, and 18% achieving the MCID in the SRS-22r total-score, function domain, pain domain, self-image domain, mental health domain, and ODI, respectively. Conclusions: In a cohort undergoing revision surgery for ASD, the most frequently encountered indications were malalignment, pseudarthrosis, and degenerative conditions. Statistically significant improvements in PROMs were identified at most recent follow-up despite high overall complication and additional revision surgeries. Steven Roth 1 , Fthimnir Hassan 2 , Erik Lewerenz 2 , Nathan Lee 3 , Chun Wai Hung 4 , Justin Scheer 5 , Joseph Lombardi 2 , Zeeshan Sardar 2 , Ronald A. Lehman 2 , Lawrence Lenke 2 1 University of Florida Medical Center, Gainesville, United States , 2 Columbia University Irving Medical Center, New York, United States , 3 Midwest Orthopaedics at RUSH, Chicago, United States , 4 Houston Methodist, Houston, United States , 5 Cedar Sinai Medical Center, Los Angeles, United States Introduction: It is unclear if the site of the most recent surgery (i.e. same versus outside center) has an impact on outcomes following revision adult spinal deformity (ASD) surgery. We sought to assess for differences in long-term outcomes, complication rates and patient reported outcome measures (PROMs) between these cohorts. We hypothesize that familiarity with patient-specific pathology should lead to improved outcomes when the most recent/index surgery was performed at the same center (SC). Methods: A retrospective review of a prospectively collected, single-center database was performed to identify ASD patients undergoing revision surgery with a minimum of 2 year follow-up. Site of most recent operation, patient and operative characteristics, postoperative complications, and PROMs, specifically the Scoliosis Research Society-22r (SRS-22r) and the Oswestry Disability Index (ODI), were collected and analyzed. The outcomes of interest included comparisons of the long term-complication rate, overall reoperation rate, and change in PROMs and their respective domains. Results: 149 patients were included in this analysis (SC = 29, OC = 120). OC patients had a greater number of prior surgeries (2.6 ± 3.5 vs 1.7 ± 1.5, p = 0.038) and fewer previously instrumented levels (9.1 ± 5.2 vs 11.8 ± 5.4, p = 0.018). SC patients were more likely to present with implant failure (41% vs 20%, p = 0.016), while OC patients were more likely to present with malalignment (78.3% vs 55.2%, p = 0.0109), curve progression (41% vs 17%, p = 0.018), and distal junctional kyphosis (DJK) (23% vs 4%, p = 0.015). OC patients had longer operative (OR) times (8.3 ± 2.1hrs vs 5.8 ± 2.2hrs, p < 0.0001), greater estimated blood loss (EBL) (1548 ± 793cc vs 886 ± 633cc, p < 0.0001), and more changes to the lower instrumented vertebrae (LIV) (62% vs 24%, p = 0.0003) with more OC patients being extended to the pelvis (50% vs 17%, p = 0.0014). No differences were observed in the distribution of the upper instrumented vertebrae (UIV) and performance of 3-column osteotomies (3COs) (p > 0.05). Although, OC patients had a greater length of stay (LOS) (8.6 ± 16.1d vs 5.2 ± 3.2d, p = 0.031). OC patients had a lower overall postoperative complication rate (43% vs 72%, p = 0.005) with the biggest comparison being among the postoperative pseudarthrosis rate (OC: 14% vs SC: 35%, p = 0.011). As a result, OC patients were less likely to return to the OR (28% vs 62%, p = 0.0004). OC patients had greater improvement in total SRS-22r scores (0.9 ± 1.3 vs 0.1 ± 1.2, p = 0.021) as well as in the self-image (1.3 ± 1.0 vs 0.7 ± 1.3, p = 0.0397), mental health (0.4 ± 0.9 vs -0.1 ± 0.9, p = 0.0361), and satisfaction domains (1.7 ± 1.3 vs 0.3 ± 1.2, p = 0.0001). Interestingly, OC patients had lower baseline levels of satisfaction (2.6 ± 1.1 vs 3.5 ± 1.3, p < 0.0001). Conclusions: Adult spinal deformity patients coming from an outside center had greater improvement in PROMs and lower postoperative complication rates despite a higher mean number of prior surgeries, more complex revision operations, and greater LOS. The reason for these differences is unclear but may hinge on higher baseline dissatisfaction Marcos Vaz de Lima 1,2 , João Paulo Trecco 3 , Eduardo Achar Filho 3 , Robert Meves 3 1 Santa Casa de São Paulo, São Paulo , 2 Instituto Tecnológico de Aeronáutica - ITA, São José dos Campos, Brazil , 3 Santa Casa de São Paulo, São Paulo, Brazil Introduction: Lower back disorders are prevalent and a significant reason for orthopedic care visits. In 2020, 619 million people experienced low back pain, expected to rise to 843 million by 2050. A common cause is the presence of a lumbosacral transitional vertebra (LSTV). Bertolotti’s syndrome is characterized by the presence of a LSTV associated with low back pain. Objectives: This study evaluates the prevalence of Bertolotti syndrome in an Orthopedic outpatient clinic and assesses interobserver reliability of LSTV classifications. Methods: A retrospective analysis of 1023 lumbar spine radiographs from patients presenting with low back pain in a large orthopedic hospital from 2018 to 2020 was conducted. After exclusions, 469 radiographs were analyzed. Two orthopedists classified LSTVs using Tini and Castellvi’s systems. Statistical analyses included the Kappa agreement index, two-proportion Z test, confidence interval for the mean, and p-value calculations. Results: The prevalence of Bertolotti syndrome was 62.5% for observer A and 61.6% for observer B. Type I LSTV was the most common, with over 70% of cases, followed by type III at over 15%. The most frequent morphology was bilateral involvement of the transverse process, with more than 50% of cases exhibiting IB morphology according to both classifications. Conclusion: This study found a high incidence of Bertolotti syndrome (over 60%) in patients with low back pain seeking orthopedic care, suggesting that LSTV should be more frequently considered in differential diagnoses. Improved recognition of LSTV could lead to better management strategies for low back pain associated with this congenital anomaly. Wesley Martins 1 , Tiago Albino 1 , Leonardo Lerro 1 , Jorge Rafael Durigan 1 , Rafael Trincado 1 , João Tomás Garcia 1 , Rodrigo Goes 1 , Alberto Gotfryd 1 , Maria Fernanda Silber Caffaro 1 , Robert Meves 1 1 Santa Casa de Misericordia de Sao Paulo, Sao Paulo, Brazil Introduction: The specialty of orthopedics and traumatology is subdivided into numerous subspecialties, including spinal surgery. In highly complex hospitals of the Brazilian Unified Health System (SUS), we find a high diversity of patients treated and operated on by this subspecialty, such as: patients with spinal deformities, chronic pain, spinal fractures, tumors, degenerative processes, among others. In addition, there are various stages of these diseases, varying in severity, urgency and demand for care. Material and Methods: Data were collected from patients undergoing outpatient follow-up or after surgical treatment in the spine group of a Brazilian quaternary hospital, entered into the Red Cap® platform. Continuous variables will be recorded as mean, standard deviation, median and interquartile range values. Categorical variables, in turn, will be recorded by their absolute number of occurrences and their percentages. For internal consistency analysis, Cronbach's alpha reliability test will be used in each group of questions that characterized a domain of the questionnaire, in addition to the overall internal consistency index involving the entire questionnaire. Data analyses will be performed using the SPSS 23.0 for MAC program (IBM SPSS Inc., Chicago, IL). A p-value < 0.05 will be considered statistically significant. For discriminative validity, comparisons between categorical variables will be performed using non-parametric tests (Kruskar-Wallis and Mann-Whitney U) and Spearman's correlation coefficients will be used for continuous variables. Results: A cohort of 4,192 patients who attended the outpatient clinic was analyzed. The average age of the patients was 46.2+20.6 years, with the youngest being under 0 years old and the oldest being 94 years old. Males were the most frequent, accounting for 57.8% of the cases. The most frequent diagnoses were low back pain (26.2%) of the cases, followed by lumbar hernia (7.6%), thoracolumbar fracture (7.3%), metastasis (5%) and other unclassified diagnoses (3.6%). The average follow-up time at the outpatient clinic was 15.9+46.9 months. Regarding treatment, 71.4% of the cases received observation, followed by surgery in 18.3% of the cases. A cohort of 893 patients who underwent surgery was analyzed. Mean age of patients was 47.7+18.67 years, with the youngest being 1 year old and the oldest being 93 years old. Males were the most frequent gender, 54.2% of cases. The most frequent diagnoses were low back pain, 16.9%, followed by lumbar hernia (12.6%), and metastasis (12.3%). Most did not await surgery, 95.6%. However, 3% were high priority and 1.4% were elective surgeries. The surgical follow-up time was on average 0.36+5.62 months. Regarding evolution, the most frequent was a satisfactory evolution without complications, followed by an unsatisfactory evolution with complications, 3.9%. Conclusion: Most outpatients and patients who underwent surgery were male. The main diagnosis was low back pain for both groups. The average follow-up time for outpatients was 15 months and the average surgical time for surgical approach was 5 months. The postoperative complication rates were 3.9%, with postoperative pain being the most common. Haley Nadone 1 , Lovingly Ocampo 1 , Dipak Maharjan 2 , Subin Byanjankar 2 , Dheera Ananthakrishnan 3 , Don Park 1 , Sohaib Hashmi 1 , Hao-Hua Wu 1 1 University of California, Irvine, Department of Orthopaedic Surgery, Global Spine Research Initiative, Orange, United States , 2 Star Hospital, Kathmandu, Nepal , 3 Emory University, Atlanta, United States Introduction: Tuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the oldest microorganisms known to exist. While M. tuberculosis principally affects the respiratory system, 15% of all TB infections globally are found in extrapulmonary locations. Spinal tuberculosis, otherwise known as Pott’s Disease, is the hematogenous spread of mycobacterium to the spine. This disease primarily affects people in low- and middle- income countries (> 80%). Today, the greatest number of new TB cases arise in the South-East Asian Region, which accounts for 46% of all new cases. In Nepal, it is estimated that there are currently 117,000 people living with TB in the country. The objectives of this study were to characterize the epidemiology of spinal tuberculosis in Nepal, characterize the diagnosis, treatments and outcomes of spinal tuberculosis patients in Nepal as well as to assess the research landscape regarding spinal TB in the country. Material and Methods: This systematic review followed PRISMA guidelines. A comprehensive search of PubMed, Google Scholar, Embase, Web of Science, Scopus, Cochrane Library, and Nepal Journals Online databases was conducted to identify studies published up to September 2024, focusing on spinal tuberculosis in Nepal. Search terms related to and including “spinal tuberculosis,” “Pott’s Disease,” “Pott’s Spine” and “Nepal.” Inclusion criteria were studies that addressed the epidemiology, diagnosis, treatment, and outcomes of spinal TB patients in Nepal. Exclusion criteria were non-English articles, and studies lacking spinal TB specificity. Two reviewers independently screened titles, abstracts, and full texts, resolving discrepancies through discussion and consensus. Data was extracted and synthesized qualitatively utilizing the systematic review software Covidence. Results: In total, 581 studies were imported for screening across all references. 142 duplicates were removed and 439 studies proceeded to abstract and title screening. 212 studies were found to be irrelevant, and 227 full-text articles were analyzed. After full text analysis, 196 studies were excluded, most commonly for not being set in Nepal. Overall, 31 studies were included in the final review. The systematic review identified a limited number of studies addressing spinal tuberculosis in Nepal, with most focusing on epidemiology, diagnosis, and treatment outcomes. Variability was observed in diagnostic approaches and treatment protocols, reflecting both resource constraints and inconsistent clinical guidelines. Reported outcomes varied widely, with some studies noting improved patient recovery, while others highlighted significant complications, including neurological deficits and delayed diagnosis. Conclusion: This systematic review highlights the limited availability of high-quality evidence on spinal tuberculosis in low- and middle-income countries (LMICs), including Nepal. The findings suggest that while progress has been made in understanding the epidemiology, diagnosis, and treatment of spinal TB, significant gaps remain. More robust, high-level studies are needed to guide effective interventions and improve outcomes. Addressing these research gaps will have important implications for public health strategies, clinical management, and the overall burden of spinal TB in LMICs. Enhanced research efforts could contribute to better healthcare planning and resource allocation in regions most affected by the disease, leading to improved healthcare outcomes for all. Haley Nadone 1 , Aura Elias 2 , Don Park 1 , Sohaib Hashmi 1 , Hao-Hua Wu 1 1 University of California, Irvine, Global Spine Research Initiative, Orange, United States , 2 UCLA, David Geffen School of Medicine, Los Angeles, United States Introduction: Cervical myelopathy (CM) is a condition resulting from spinal cord compression in the cervical region, leading to significant morbidity. The epidemiology, diagnosis, and management of CM can vary greatly across different regions. Despite its clinical significance, research focusing on CM in Latin America and the Caribbean is sparse. This scoping review aims to map the current state of research related to CM within these regions, examining the populations affected, diagnostic approaches, and treatment strategies. Material and Methods: This systematic review adhered to PRISMA guidelines. A thorough search was performed across multiple databases, including PubMed, Google Scholar, Embase, Web of Science, Scopus, and Cochrane Library to identify relevant studies addressing CM in Latin America and the Caribbean published up to August 2024. The regions covered in our search included Latin American countries (Mexico, Central America, and South America) and Caribbean nations (including but not limited to Cuba, Puerto Rico, and Jamaica) as per World Bank guidelines. Databases were systematically searched using the various country keywords as well as “Cervical Myelopathy,” “Caribbean,” and “Latin America.” Studies were reviewed for relevance based on predefined inclusion criteria, including geographic and content focus and language. We excluded articles not published in English and those not specifically addressing CM or those from different settings. Results: Our search originally identified 1848 studies. A total of 1157 studies were screened after duplicates were removed. Epidemiological data showed a range of CM prevalence across different countries, with more studies originating from Brazil and Mexico. Diagnostic practices varied widely, with MRI being the most commonly used imaging technique, though access to advanced imaging was uneven. Treatment approaches also exhibited considerable diversity, with some regions favoring conservative management and others opting for more advanced surgical interventions. Information on minimally invasive or endoscopic spine procedures was minimal, reflecting a gap in the available research. Notably, there was a lack of uniformity in treatment protocols and a limited number of studies on long-term outcomes. Conclusion: This scoping review underscores the limited availability of comprehensive and high-quality evidence on cervical myelopathy in Latin America and the Caribbean. While some progress has been made in understanding the epidemiology, diagnostic practices, and treatment approaches for CM in these regions, notable gaps persist. The findings indicate the need for more standardized research and clinical guidelines tailored to the specific needs of these populations. Future research should aim to unify diagnostic criteria and treatment protocols to improve CM management outcomes in Latin America and the Caribbean. Enhanced regional collaboration and investment in research infrastructure could bridge existing gaps and lead to more consistent and effective care for individuals affected by cervical myelopathy in these diverse and underserved regions. Addressing these research gaps is crucial for refining public health strategies, optimizing clinical management, and reducing the overall impact of cervical myelopathy in Latin America and the Caribbean. Haley Nadone 1 , Ariana Rowshan 2 , Mengistu Gebreyohanes 3 , Sohaib Hashmi 1 , Don Park 1 , Hao-Hua Wu 1 1 University of California, Irvine, Department of Orthopaedic Surgery, Global Spine Research Initiative, Orange, United States , 2 Georgetown University, Washington, DC, United States , 3 Hawassa University, Department of Orthopedics, Hawassa, Ethiopia Introduction: Back pain and degenerative spine diseases are major global health concerns, receiving substantial research funding in high-income countries. In contrast, low- and middle-income countries (LMICs) – which bear a disproportionate burden of these conditions – often receive minimal research investment. This disparity, known as the 10/90 gap, highlights the underrepresentation of LMICs in spinal research. This study aims to evaluate the current state of orthopedic spine research in Ethiopia, an LMIC, and identify priority areas for future investigation to address this gap. Material and Methods: A comprehensive literature review was conducted focusing on studies related to orthopedic spine conditions in Ethiopia. Research articles were sourced from Google Scholar, PubMed and the National Center for Biotechnology Information (NCBI) databases using search terms such as “Orthopaedic,” “Spine,” and “Ethiopia.” Inclusion criteria encompassed studies conducted in Ethiopia or involving Ethiopian populations, specifically addressing orthopedic spine conditions, diagnosis, treatments, and epidemiology. Data from these studies were analyzed to assess the current state of research and to identify gaps and areas needing further exploration. Results: The review identified a limited but growing body of research on orthopedic spine conditions in Ethiopia. Key findings include a notable focus on epidemiological studies, which reveal a high prevalence of spine disorders related to poor socioeconomic conditions and limited access to healthcare. Diagnosis and treatment research is relatively sparse, with a need for more detailed studies on specific spine pathologies and effective treatment modalities. Notably, existing studies often lack comprehensive data on the effectiveness of various treatment approaches and the impact of socioeconomic factors on spine health. The review also highlighted a significant gap in research related to minimally invasive treatments tailored to the Ethiopian context. Additionally, there is a marked scarcity of long-term studies and randomized controlled trials (RCTs), which hinders the ability to assess the long-term efficacy and safety of treatment interventions. Conclusion: The current state of orthopedic spine research in Ethiopia reflects a nascent but essential effort to understand and address spine-related health issues in a low-resource setting. However, there are critical gaps in research that need to be addressed to improve spine health outcomes. Future research should prioritize investigating cost-effective and contextually appropriate diagnostic and treatment methods, as well as exploring the broader socioeconomic factors impacting spine health. Addressing these areas, and increasing the focus on long-term studies and RCTs, will help bridge the 10/90 gap and align global research efforts with the needs of populations in LMICs, ultimately improving health outcomes and resource allocation in these regions. Ahmad Hussien 1 , Edward Roberts 1 , Colin Bruce 1 , Neil Davidson 1 , Jayesh Trivedi 1 , Daniel Perry 2 , Sudarshan Munigangaiah 1 1 Alder Hey Children’s Hospital, Spine Disorders Unit, Liverpool, United Kingdom , 2 Alder Hey Children’s Hospital, Orthopedic, Liverpool, United Kingdom Background: Delayed presentation of scoliosis with large cobb angle is common in the UK, with larger curves worsening the overall prognosis. We hypothesized that worsening socioeconomic deprivation may lead to increases in the diagnostic delay, with greater curve size at first presentation. The aim of this study was to identify the relationship between deprivation score and different demographics and the presence of severe deformity at first presentation. Methods: We conducted a case control study amongst patients presenting to Alder Hey children’s hospital. Cases were defined as those with a 70 degree and larger curve at their initial presentation between 2013 and 2022. Controls were defined as curves between 10 and 70 degrees presenting over the same period. Controls were allocated on a 2:1 basis. Participant postcodes were used to define the degree of deprivation, using the 2019 IMD English Index of multiple deprivation score. The IMD score was consider as both a rank, of the 32,844 super output areas, and as a deprivation decile. Analysis was conducted using descriptive statistics and logistic regression. Results: 124 cases and 240 controls were included, Graphically the relationship between the IMD rank and the participants did not reveal any apparent differences between the groups. Logistic regression analysis confirmed this and was unable to demonstrate a difference and p values were persistently > 0.10 with no evidence against the null hypothesis. Conclusions: We were unable find evidence to support our hypothesis. This may mean that the hypothesis is indeed false, though may also mean that the methods meant that this was unable to be identified. One possibility is overmatching – where the populations and controls are too similar to identify a difference, which may be evident in a population with such high levels of deprivation, such as that seen within Liverpool. Jarod Olson 1 , Jonathan Dalton 1 , Omar Tarawneh 1 , Rajkishen Narayanan 1 , Alec Giakas 1 , Robert Oris 1 , Nicholas Pohl 1 , Zuhair Al-Bahrani 2 , William Sutton 3 , Jake Fanizza 3 , Grace Bowen 2 , Jose Canseco 1 , Alan Hilibrand 1 , Alex Vaccaro 1 , Gregory Schroeder 1 , Chris Kepler 1 1 Rothman Orthopaedic Institute, Orthopaedic Surgery, Philadelphia, United States , 2 Sidney Kimmel Medical College, Philadelphia, United States , 3 Drexel University College of Medicine, Philadelphia, United States Introduction: Recently, orthopaedic research output has increased exponentially, due in part to the use of large databases. Between 2013 and 2015, the number or publications incorporating large databases increased by 175%. While these databases increase statistical power, some studies have highlighted variability in data coding practices and a lack of granularity as potential weaknesses of this methodology. The aim of the current study is to identify trends in large database utilization across prominent spine surgery journals to assess their impact and growth over time. Material and Methods: Articles published from 2012-2022 across six major spine journals were analyzed: Global Spine Journal (GSJ), Spine, The Spine Journal (TSJ), European Spine Journal (ESJ), International Journal of Spine Surgery (IJSS), and Journal of Neurosurgery-Spine (JNS). Three independent researchers manually reviewed each volume and issue of the above journals over the ten-year period for inclusion of the following major databases as a data source: National Inpatient Sample (NIS), Centers for Medicare & Medicaid Service Data (CMS), National Surgical Quality Improvement Program (NSQIP), National Trauma Data Bank (NTDB), PearlDiver (PD), and IBM Market Scan (MS). Studies were excluded if they were basic science, commentaries, letters to the editor, systematic reviews, meta-analyses, or published as a special issue or invited article. Descriptive statistics were reported as percent of the total for categorical variables and mean and standard deviations for continuous variables. p-values < 0.05 were considered statistically significant. Results: A total of 409 spine studies using large databases were included. The number of spine surgery studies increased over the ten-year period with a max of 157 studies in 2017-2018 (p < 0.001). From 2012-2022, the journal-specific distribution showed a decrease in Spine (68.7% to 29.5%), increase in GSJ (0% to 29.5%), and consistent trend in TSJ (25.4% to 26.3%, p < 0.001). Database use varied but PearlDiver was the most used in every time period (p < 0.001). There was an increase in first authors with BS/BA degrees (22.4% to 40.0%, p < 0.001) and number of affiliated institutions (2.30 to 3.44, p < 0.001) from 2012 to 2022. Study topics saw a decrease in surgical complications (still the most frequent topic, 40.3% to 25.3%) and increase in pre-operative risk factors (7.46% to 16.8%, p < 0.001). Conclusion: This study demonstrates that the use of large databases has expanded significantly in spine literature within the last decade. The utilization of these databases has increased the capacity for inter-institutional collaboration and the inclusion of undergraduates and medical students in authorship. Additionally, this practice has increased the statistical power of these analyses, which allows for exploration of novel topics and rare complications. However, further investigation is needed to evaluate and address concerns over data heterogeneity, potentially low clinical significance of statistically significant results, and the ability to draw conclusions from agranular large datasets. Fabrizio Russo 1 , Gianluca Vadalà 1 , Giuseppe Francesco Papalia 1 , Luca Ambrosio 1 , Giorgia Petrucci 1 , Cristina Di Tecco 2 , Sergio Iavicoli 3 , Rocco Papalia 1 , Vincenzo Denaro 1 1 Campus Bio-Medico University Hospital Foundation, Rome, Italy , 2 Italian Workers' Compensation Authority (INAIL), Rome, Italy , 3 Ministry of Health, Rome, Italy Introduction: Low Back Pain (LBP) stands out as a prevalent musculoskeletal issue, representing a significant global health challenge and a leading cause of disability. Given its multifaceted origins, addressing LBP necessitates a comprehensive understanding. Multidisciplinary approaches may help reduce the burden of pain and disability and improve job continuity and reintegration at work. This study examines the interplay between functional disability and work ability in workers affected by LBP through an analysis of correlations between the Oswestry Disability Index (ODI) and Work Ability Index (WAI). Additionally, the study assesses the impact of personal and work-related factors on levels of functional disability and work ability. Material and Methods: A cohort of 264 patients affected by LBP due to degenerative disc disease were included in a clinical diagnostic/therapeutic trial aiming at rehabilitation and return to work through an integrated investigation protocol. Data collection occurred during the initial medical examination, utilizing anamnestic tools to evaluate occupational and health-related characteristics, along with assessments of WAI and the ODI. Statistical analyses were conducted using Stata v. 16.0 (StataCorp LP, College Station, TX, USA). Descriptive statistics were computed for demographic, work, and clinical features. The degree of association between ODI and WAI was assessed using Pearson's correlation coefficient with a bootstrap method for confidence interval determination. Univariate odds ratios (OR) were also employed to explore the relationship between WAI and ODI scores. Additionally, multivariate binary logistic regression analyses were introduced to examine the associations between occupational and health-related characteristics and WAI and ODI scores. Results: The final sample consists of 252 patients, with 57.1% being male, 44.0% engaged in blue-collar occupations, 46.4% holding a high school degree, and 45.6% being married. The WAI and ODI exhibited a negative and fair correlation (r = -0.454; p = .000). Notably, chronic LBP is associated with a reduced likelihood of severe disability compared to acute LBP. However, it is also linked to a diminished probability of enhanced work ability. The presence of depressive symptoms significantly influences the levels of work ability. White-collar workers without depressive. Conclusion: This study underscores the multifaceted nature of LBP, revealing that ODI and WAI are correlated yet encapsulate distinct facets of disability associated with individual, environmental, and occupational factors. A comprehensive assessment and therapeutic model that prioritizes a multidisciplinary approach emerge as optimal for effectively addressing LBP. This approach not only facilitates treatment but also promotes employability and sustained participation in the workforce. André Nishizima 1 , Philippe Monteiro 1 , Luciano Carneiro Filho 1 , Rafael Silva 1 , Kenzo Donato 1 , Raimundo Fernandes 1 1 Bahiana School of Medicine and Public Health, Medicine, Salvador, Brazil Introduction: Intervertebral disc disorders (IDD) are a common cause of disability and hospitalization in Brazil, leading to significant healthcare costs. This ecological study examines the epidemiological profile and temporal trends in hospitalization rates for IDD in Brazil, utilizing data from DATASUS between 2011 and 2021. Material and Methods: Data were obtained from DATASUS, the Brazilian public health system's database, which provides comprehensive information on hospital admissions nationwide. Hospitalization data for IDD from 2011 to 2021 were analyzed. A linear regression model was applied to evaluate trends from 2013 to 2023, estimating the annual rate of change in hospitalizations. The epidemiological profile focused on the distribution of cases by age, gender, type of admission (elective vs. urgent), average length of stay, and healthcare costs. Results: Between 2011 and 2021, a total of 154,427 hospitalizations for IDD were recorded in Brazil, with the highest number of cases in 2014 (16,630). The linear regression analysis revealed a slope of -391.43 hospitalizations per year (95% CI: -791.52 to 8.67), with an R 2 value of 0.3524, indicating that approximately 35% of the variation in hospitalization rates is explained by time. However, the p-value of 0.0542 suggests that this decline was not statistically significant. A notable reduction in hospitalizations was observed during 2020 and 2021, with hospitalizations dropping to 9,441 in 2020 and 9,115 in 2021. The epidemiological analysis showed that hospitalizations were most frequent among older adults, particularly those aged 50 and above, with a slight female predominance (more than 50% of cases). Elective admissions constituted the majority of hospitalizations, reflecting the planned nature of IDD treatments, though urgent admissions, likely associated with acute exacerbations, also represented a significant proportion. Additionally, the average length of hospital stay decreased from 7.7 days in 2011 to 6.1 days in 2021. The total healthcare costs for IDD hospitalizations during the study period amounted to BRL 879.35 million. Conclusion: While the analysis suggests a general downward trend in hospitalizations for intervertebral disc disorders over the study period, the lack of statistical significance (p = 0.0542) implies that external factors may have influenced this pattern. It is plausible that the observed decrease in hospitalizations, particularly in 2020 and 2021, could be partially attributed to disruptions in healthcare services during the COVID-19 pandemic, which may have led to a reduction in elective procedures and hospital admissions for non-urgent conditions. Future studies incorporating data from post-pandemic years are necessary to determine whether this trend continues or if hospitalization rates return to pre-pandemic levels. Daniel Ortega 1 , Yaxel Levin-Carrion 2 , Brendan Schwartz 1 , Justin Reyes 1 , Joseph Lombardi 1 , Zeeshan Sardar 1 1 Columbia University Medical Center, New York, United States , 2 Rutgers University, New Jersey, United States Introduction: Racial and ethnic health disparities are well-documented in various medical specialties. Research shows these disparities also exist in surgical specialties such as spine surgery. Though there have been studies that investigated disparities in the complication rates following spine surgery using national databases, there is a lack of recent research investigating such disparities across spine surgery concerning various racial and ethnic groups, such as Hispanic and Native American Patients. This study uses the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database to show racial and ethnic identity (REI) as an independent predictor of postoperative complications following spine surgery. Material and Methods: Data from patients who underwent spine surgeries within the ACS-NSQIP databases from 2015 to 2020 were analyzed in this study according to relevant current procedural terminology codes with complete case analysis. Demographic, comorbidity, and complication data were compared by REI using chi-square and Kruskal-Wallis tests. Complications and post-operative categorical variables were combined into “combined occurrences” (wound, respiratory, urinary, cardiovascular, septic complications, and postoperative events) and compared with logistic regression by REI. Hospital times data was compared with both Kruskal-Wallis and linear regression. Regressions all controlled for age, weight, sex, and reported comorbidities. Significance was set at less than 0.05. Results: 181,913 white (82.09%), 21,501 black (9.70%), 10,710 Hispanic (4.83%), 5,611 Asian (2.53%), 1,249 Native American (NA) (0.56%), and 628 Native Hawaiian (NH) (0.28%) patients were in our analysis. Black patients experienced the highest rates of dyspnea (4.86%), diabetes (24.95%), and hypertension (63.49%), which was significantly different from the other groups (p < 0.0001). Additionally, black patients had significantly higher body mass indexes at 31.97 (p < 0.0001). White and Asian patients were significantly older than their counterparts when presenting for surgery (58.53, 58.99; p < 0.0001). NA patients had the highest smoking rates at 30.42% (p < 0.0001). Uncontrolled analyses of complication rates found that surgical site infections, pulmonary embolisms, renal insufficiency, cardiac arrests, and all combined occurrences significantly differed based on REI (all p ≤ 0.020). Regression analyses revealed that black patients experienced higher wound, respiratory, urinary, cardiovascular, septic complications, and post-operative events compared to white patients (Odds ratio (OR) = 1.55, 1.35, 1.32, 1.29, 1.22; all p ≤ 0.0072). Hispanic patients had lower wound complications but higher urinary complications and post-operative events (OR = 0.82, 1.23, 1.11; all p ≤ 0.041). Asians had lower respiratory, cardiovascular complications, and post-operative events (OR = 0.66, 0.65, 0.79; all p ≤ 0.030). NA had higher rates of wound, septic complications, and post-operative events (OR = 1.88, 1.96, 1.29; all p ≤ 0.033). No significant differences were found in regression analyses for NH patients, but 4/6 combined occurrences had higher odds than white patients. Conclusion: REI significantly predicts disparities in postoperative complications following spine surgery. Black patients experienced the highest rates of comorbidities and were at an increased risk for various complications after controlling for multiple variables compared to white patients. Hispanic and NA similarly also experience increased rates of complications, whereas Asians have better outcomes. Addressing these disparities through targeted interventions such as improved postoperative monitoring and improved guidelines may help bring health equity to all. Rodolfo Gomes Dias 1 , Alysa Almojuela 1 , Michael Johnson 1 , Jay Toor 1 , Neil Berrington 1 , Michael Goytan 1 , Perry Dhaliwal 1 1 Health Science Centre/ University of Manitoba, Winnipeg Spine Program, Department of Neurosurgery, Winnipeg, Canada Introduction: Symptomatic pseudarthrosis, a complication of spinal fusion surgery characterized by nonunion of the vertebrae, is a significant concern in post-operative care. It often necessitates revision surgery, incurring substantial costs for healthcare systems. In Brazil, where the public healthcare system (SUS) serves approximately 75% of the population, understanding the trends and financial implications of revision surgeries for pseudarthrosis is crucial. This study analyzes the trends in arthrodesis revision/pseudoarthrosis procedures for the cervical, thoracic, and lumbar spine within the Brazilian public health system from 2019 to 2023, with a specific focus on the impact of the COVID-19 pandemic. Materials and Methods: This observational study utilized comprehensive data from the Hospital Information System (SIH/SUS), accessed through the Department of Informatics of the Unified Health System (DATASUS). Procedure codes from the Management System of the SUS Table of Procedures, Medications, Orthotics, and Prosthetics (SIGTAP) were employed to identify relevant cases. Ethical approval was not required as the data is publicly accessible according to Resolution No. 510/2016-CNS. The analysis focused on the number of procedures performed, the total cost incurred, and the average cost per procedure over the five-year period. Descriptive statistics were employed to elucidate the national epidemiology of revision arthrodesis for pseudoarthrosis in spine surgical procedures, and a Chi-square test was conducted to assess the statistical significance of any observed trends, with a significance level set at p < 0.05. Results: The data from 2019 to 2023 revealed notable fluctuations in the number of revision arthrodesis for pseudoarthrosis in spine surgical procedures and associated costs in Brazil. In 2019, 691 procedures were performed, but this number significantly declined by 28.7% (p < 0.05) to 493 in 2020, coinciding with the onset of the COVID-19 pandemic. A slight recovery of 1.8% occurred in 2021, with 502 procedures, followed by a substantial increase of 31.9% (p < 0.05) in 2022, reaching 662 procedures. However, 2023 witnessed another decrease of 7.6%, bringing the number of procedures down to 612. The total cost mirrored these trends, with a decrease from 1,698,957.52 BRL in 2019 to 1,309,205.00 BRL in 2020, followed by a gradual rise to 1,842,854.61 BRL in 2022 and a subsequent decrease to 1,675,517.35 BRL in 2023. Notably, the average cost per hospitalization showed an upward trend, increasing from 2,458.69 BRL in 2019 to 2,737.77 BRL in 2023, indicating a growing financial burden on the healthcare system. Conclusion: This study demonstrates the significant impact of the COVID-19 pandemic on the number of spinal surgeries performed in Brazil, particularly for revision arthrodesis for pseudoarthrosis in spine surgical procedures. While a gradual recovery in the number of procedures was observed in the years following the pandemic's onset, the financial burden on the healthcare system has increased, as reflected in the rising average cost per hospitalization. This highlights the need for continued monitoring and evaluation of healthcare resource allocation and cost management strategies to ensure optimal care for patients requiring revision surgeries for spinal pseudarthrosis in Brazil. Additionally, understanding the long-term effects of the pandemic on healthcare utilization patterns and resource allocation will be crucial for informing future healthcare policy decisions. Rodolfo Gomes Dias 1 , Jay Toor 1 , Alysa Almojuela 1 , Michael Goytan 1 , Neil Berrington 1 , Michael Johnson 1 , Perry Dhaliwal 1 1 Health Science Centre/ University of Manitoba, Winnipeg Spine Program, Winnipeg, Canada Introduction: Thoracolumbosacral spine fusion (TLSF) is essential for treating various spine-related pathologies, including degenerative diseases, trauma, and deformities. The procedure aims to fuse vertebral segments, restoring stability and alignment compromised by these conditions. This study examines five-year trends and the impact of the COVID-19 pandemic on TLSF procedures within Brazil's public health system. Materials and Methods: This observational study utilized data from the Hospital Information System (SIH/SUS) accessed via DATASUS, using procedure codes from the Management System of the SUS Table of Procedures, Medications, Orthotics, and Prosthetics (SIGTAP). Ethical approval was not required as the data are publicly accessible under Resolution No. 510/2016-CNS. The analysis focused on the number of procedures, total cost, and average cost over a five-year period (2019-2023) across Brazil's regions. Data were organized in a spreadsheet, and descriptive statistics were used to understand national epidemiology, considering that approximately 75% of Brazilians rely on the Unified Health System. A Chi-square test was conducted, with significance set at p < 0.05. Results: From 2019 to 2023, a total of 29,323 thoracolumbar arthrodesis surgeries - including posterolateral approach (1-3 levels), anterior approach (1-3 levels), and posterior approach (1-7 levels) - were performed across Brazil. In 2019, 6,564 surgeries were conducted nationwide, dropping to 4,695 in 2020, marking a 28.5% decrease largely attributed to the COVID-19 pandemic. In 2021, surgeries increased slightly by 3.1% to 4,840. The upward trend continued in 2022, with a 27.6% (p < 0.05) increase to 6,175 surgeries, and in 2023 reached 7,049 - a 14.2% increase. Regionally, the Southeast had the highest number of surgeries (11,547) over the five years, while the North had the fewest (1,172). The Southeast experienced a 26.3% (p < 0.05) decrease from 2,488 surgeries in 2019 to 1,835 in 2020. The North saw a larger reduction of 34.7% (p < 0.05), from 268 to 175 surgeries during the same period. The Northeast region rebounded in 2021 with a 21.1% increase from 582 surgeries in 2020 to 705 in 2021, continuing to grow in subsequent years. By 2023, the North had the highest growth rate, increasing 61.0% (p < 0.05) from 200 surgeries in 2022 to 322 in 2023. Conclusion: The analysis indicates that thoracolumbar arthrodesis surgeries within Brazil's public health system experienced a significant decline in 2020 due to the COVID-19 pandemic, followed by a robust recovery in subsequent years. Regional disparities highlight uneven impact and recovery, with the Southeast consistently having the highest number of surgeries. While the prevalence of spinal pathologies in Brazil is not precisely known, the rate of thoracolumbosacral arthrodesis is well below that of the United States, which performed approximately 199,140 procedures (79.8 per 100,000 population) in 2015. The Brazilian system, by comparison, performs significantly fewer surgeries, suggesting potential limitations in access to surgical care and resources. These findings underscore the importance of continuous monitoring to address regional disparities and improve healthcare delivery in Brazil. The marked difference in procedures between Brazil and the United States highlights the need for enhanced healthcare infrastructure and resource allocation to meet the growing demand for spine surgeries in Brazil. Viswanadha Arun-Kumar 1 , Luca Ambrosio 2 , Hans-Jörg Meisel 3 , Zorica Buser 4 , Gianluca Vadalá 2 , S. Tim Yoon 5 , Sathish Muthu 6,7,8 1 Reva Spine Centre, Vishakapatnam, India , 2 Campus Bio-Medico University of Rome, Department of Orthopaedic and Trauma Surgery, Rome, Italy , 3 Bergmannstrost Hospital, Department of Neurosurgery, Halle, Germany , 4 Gerling Institute, New York, United States , 5 Emory University, Department of Orthopaedics, Atlanta, United States , 6 Government Medical College, Department of Orthopaedics, Karur, India , 7 Karpagam Academy of Higher Education, Department of Biotechnology, Coimbatore, India , 8 Orthopaedic Research Group, Department of Spine Surgery, Coimbatore, India Introduction: Despite the publication of guidelines towards standardized spine surgery practice, significant differences exist. This study aimed to investigate surgeons' practice modification patterns and analyse the factors affecting the implementation of guidelines in their clinical practice. Methods: An international expert survey was conducted among AO Spine members. The survey, comprising 30 items, explored surgeons' demographics, risk aversion, and factors influencing practice change. We categorized the innovation-adoptive nature of the surgeons and scored their risk-adoptive behaviour. Results: A total of 458 responses were received from surgeons across 81 countries including 433 male (94.5%), orthopaedic surgeons (n = 263; 57.4%) from university affiliated hospitals (n = 185; 40.4%). Most of the surgeons were in the early majority phase of innovation-adoption cycle (n = 174; 38.0%) within a ‘moderate’ risk-adoption category (n = 314;68.5%). This risk adoption behaviour had significant correlation with their appetite for innovation (r = 0.182, p ≤ 0.001). About 67.9% respondents preferred scientific literature and conference presentations showcasing solid clinical evidence to be the most influential in driving the change in their clinical practice. Material logistics (54.6%) was considered an important barrier to practice modification followed by familiarity (50.0%) and financial reimbursements (24.9%). Conclusion: A complex interplay exists between risk-adoptive behaviour of surgeons and the factors influencing a change in their clinical practice. Although most surgeons were in the early adoptive phase in accepting the innovations into their clinical practice, they were also equally noted to be risk averse. Hence, a successful adoption of practice changing guideline hinges on addressing not only logistical and financial challenges, but also on providing a robust scientific evidence to drive the necessary change in their clinical practice. Rodolfo Gomes Dias 1 , Neil Berrington 1 , Michael Goytan 1 , Michael Johnson 1 , Perry Dhaliwal 1 1 Health Science Centre/ University of Manitoba, Winnipeg Spine Program, Department of Orthopedics, Winnipeg, Canada Introduction: Discectomy is a surgical intervention for herniated discs causing radiculopathy unresponsive to conservative treatment. While many cases resolve without surgery, discectomy is essential for some patients. This study analyzes five-year trends (2019–2023) in cervical, thoracic, and lumbar discectomy surgeries within Brazil's Unified Health System (SUS), focusing on the impact of the COVID-19 pandemic. Materials and Methods: An observational study utilized data from the Hospital Information System (SIH/SUS) accessed via DATASUS, using procedure codes from the SUS Table of Procedures (SIGTAP). The specific procedure codes analyzed were 0408030380 (Cervical/Lumbar/Lumbosacral Discectomy via Posterior Approach, 1 Level with Microscope), 0408030399 (Cervical/Lumbar/Lumbosacral Discectomy via Posterior Approach, 1 Level), 0408030402 (Cervical/Lumbar/Lumbosacral Discectomy via Posterior Approach, 2 Levels), 0408030410 (Cervical/Lumbar/Lumbosacral Discectomy via Posterior Approach, 2 or More Levels with Microscope), 0408030429 (Anterior Cervical Discectomy, Up to 2 Levels with Microscope), 0408030437 (Anterior Cervical Discectomy, 1 Level), 0408030445 (Anterior Cervical Discectomy, 2 or More Levels), 0408030453 (Thoracic-Lumbar-Sacral Discectomy via Anterior Approach, 2 or More Levels), and 0408030461 (Thoracic-Lumbar-Sacral Discectomy via Anterior Approach, 1 Level). Ethical approval was not required per Resolution No. 510/2016-CNS, as the data are publicly accessible. The analysis examined the number of procedures, total expenditure, and average cost per procedure over five years across Brazil's regions and nationally. Data were organized in spreadsheets, and descriptive statistics were applied. Considering that approximately 75% of Brazilians rely on the SUS, the findings reflect national trends. A Chi-square test assessed statistical significance at p < 0.05. Results: From 2019 to 2023, a total of 20,303 discectomy procedures were performed, encompassing the specified procedure codes. The Southeast Region recorded the highest number (11,107), followed by the South (3,938), Northeast (2,537), Center-West (1,810), and North (911). In 2020, procedures decreased significantly due to the pandemic, from 4,683 in 2019 to 3,212 - a 31.4% reduction (p < 0.05). Regional declines were: Southeast 31.1%, South 29.5%, Northeast 44.1%, Center-West 18.4%, and North 32.8%. Procedures increased in subsequent years: 3,347 in 2021 (4.2% increase from 2020), 4,268 in 2022 (27.5% increase), and 4,793 in 2023 (12.3% increase). Total expenditure over five years was BRL 36,380,346.57. The average cost per procedure rose by 10.5%, from BRL 1,711.88 in 2019 to BRL 1,890.76 in 2023, indicating a growing financial burden on the healthcare system. Hospital service costs totaled BRL 26,697,147.94. Conclusion: The COVID-19 pandemic significantly reduced discectomy procedures in Brazil's public health system in 2020, reflecting the strain on healthcare resources. The gradual recovery in procedure numbers and expenditure suggests resilience and adaptation of the system. The increasing average cost per procedure may reflect higher case complexity, advancements in surgical techniques, or inflationary factors. Compared to the United States, where approximately 450,000 to 500,000 lumbar discectomies are performed annually, Brazil's lower numbers highlight disparities in healthcare accessibility and resource allocation. Continuous monitoring of these trends is essential for policymakers to optimize patient care and resource distribution and to develop strategies to mitigate the impact of future healthcare challenges.

Annabel Kim 1 , Joshua Sanchez 2 , Marc Abdou 1 , Zorica Buser 3 , David Cheng 1 , Gene Tekmyster 1 1 Keck School of Medicine at The University of Southern California, Orthopaedic Surgery, Los Angeles, United States , 2 Yale School of Medicine, New Haven, United States , 3 Gerling Institute, New York City, United States Study Design: Retrospective observational study. Objectives: This study aimed to characterize the effectiveness of epidural steroid injections (ESIs) in improving pain, measured with Numerical Rating Scale (NRS) scores, and their relationship with subsequent lumbar spine surgery within a one-year period. Methods: Patients who received a lumbar ESI between January 2018 and March 2022 in a single, large academic healthcare center were identified. Only patients with a one-year follow-up and no traumatic injuries were included. Exclusion criteria included a prior lumbar ESI within 5-years of January 2018. Demographics, comorbidities, injection information, and NRS scores were abstracted. NRS score comparisons were completed with the Wilcoxon signed-rank test. Significance was defined at p ≤ 0.05. Results: A total of 143 patients were identified. The patient population consisted of 43% male, 57% female, and an average age of 63 years. A significant decrease in NRS scores was noted throughout the 1-year period. One- and five-months post-ESI had the most significant decrease in NRS (-3.00 ± 4.24 and -3.42 ± 3.94, respectively). At 1-year post-ESI, there was an average decrease in NRS scores by -2.81 ± 3.14. Of the cohort, only 28 (27.2%) patients converted to lumbar spine surgery within a year. Conclusion: The data suggests ESIs may be effective at relieving pain for at least one year. The data provides some evidence that ESIs are most reliable at relieving pain up to the 5-month mark, after which their efficacy decreased. Anthony Reyes 1 , Chandan Saini 1 , Insup Hong 2 , Nathaniel Ung 3 , Hong Wu 1 1 Rush University Medical Center, Chicago, United States , 2 Loyola Strich School of Medicine, North Chicago, United States , 3 Rosalind Franklin University of Medicine & Science, North Chicago, United States Introduction: Superior cluneal nerve entrapment (SCN-E) is an underdiagnosed etiology of low back pain (LBP), that mimics common conditions such as facet joint pathology, sacroiliac joint dysfunction, or lumbar radiculopathy. The superior cluneal nerve (SCN), derived from the posterior rami of T11-L4, traverses the iliac crest through a fibrous tunnel, where it is prone to entrapment. SCN-E accounts for up to 10% of chronic LBP cases but is overlooked due to its non-specific symptoms of radiating LBP to buttocks and posterior thigh, and exclusion from standard diagnostic algorithms. Diagnostic blocks at the posterior superior iliac crest can confirm SCN-E and provide therapeutic relief. This report discusses cases of SCN-E successfully managed with targeted nerve blocks, emphasizing the importance of its consideration in refractory LBP cases. Material and Methods: Case Description: Patient #1. A 74-year-old female with a history of polymyalgia rheumatica, osteoporosis, and left knee arthroplasty presented to a pain clinic with right lower extremity pain and new-onset bilateral LBP. Physical therapy and a right trochanteric bursa injection resolved her leg pain, however, her LBP persisted, radiating down her posterior thighs. Examination revealed focal tenderness over the right SCN distribution. An ultrasound-guided right SCN injection provided > 70% pain relief for two weeks, as measured by the Visual Analog Scale (VAS). Upon recurrence, conservative management with therapy, lifestyle modifications, and multimodal pain medications was recommended. Case Description: Patient #2. A 77-year-old male with a history of multiple lumbar laminectomies presented to a pain clinic with chronic LBP and right hip pain. Despite previous treatments, including hip joint injections, transforaminal epidural steroid injections, and lumbar radiofrequency ablations, his pain persisted. He described sharp, burning pain in the right buttock, radiating to the hip, and worsened with movement. An ultrasound-guided right SCN injection was performed, which resulted in VAS score reduction from 9/10 to 2/10 and 3-4 months of significant relief. He also reported regaining functional independence and re-engaging in regular activities and hobbies. Results: We discuss the pain efficacy of ultrasound-guided nerve blocks for SCN-E in two patients. Both previously failed conservative and pharmacological therapies but experienced significant pain relief from SCN blocks, as evidenced by VAS pain score reductions. However, the duration of relief varied; Patient 1 experienced pain relief for two weeks, while Patient 2 had relief lasting at least three months. Although current literature on the duration of pain relief following SCN nerve blocks is limited, some studies report significant relief lasting from 3 months to 4 years. The differences in duration and extent of pain relief in our patients likely reflect a combination of predisposing risk factors that influence the development of SCN-E, such as age, female gender, prior lumbar or pelvic surgeries, early postpartum status, and vertebral compression fractures, along with other premorbid conditions. Conclusion: Our findings of significant pain relief following ultrasound-guided SCN blocks further support the growing evidence of the effectiveness of these blocks in managing pain, however further studies are necessary to evaluate their long-term effectiveness. Vasileios Karampikas 1 , Ioannis Trikoupis 1 , Spyridon Sioutis 1 , Panayiotis Gavriil 1 , Anastasios Roustemis 1 , Alexandros Zikopoulos 1 , Anastasios Kalampokis 2 , Ioannis Chatzikomninos 2 , Konstantinos Soultanis 1 , Panayiotis Papagelopoulos 1 , Stavros Goumenos 3 1 Attikon University General Hospital, First Department of Orthopaedics, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece , 2 KAT Attica General Hospital, Athens, Greece , 3 Virchow Klinikum, Charité - Universitätsmedizin, Berlin, Germany Introduction: Vertebral compression fractures (VCF) of the thoracolumbar spine are the most frequent spinal injuries - 1.5 million cases annually in USA. Prevailing trend regarding their management is towards non-operative treatment. However, conservative treatment entails the risk of failure with chronic pain and decreased quality of life. We evaluated the functional and clinical outcome of nonoperatively treated VCFs and investigated potential risk factors for failure of nonoperative treatment and subsequent surgery. Material and Methods: We conducted a retrospective analysis of 303 consecutive patients with stable vertebral compression fractures of the thoracolumbar junction. The measured radiographic parameters used to assess the deformity of the fractured vertebrae included local kyphotic angle (LKA), anterior body height compression rate (ABC) and degree of scoliosis (SC). Regarding the functional outcome of the patients, the intensity of pain was documented using the Visual Analogue Scale (VAS), whereas the impact of the injury on the quality of life of the patients was assessed using the Oswestry Disability Index (ODI). Results: In our cohort, 11.2% of the patients failed after nonoperative treatment. In the non-osteoporotic group 7.4% of the patients eventually underwent at least one surgical intervention, whereas the rate of osteoporotic patients that finally required operative treatment after conservative treatment failure was significantly higher (15.2%). VAS and ODI average scores of our study group that were recorded at final follow-up were 2.8 ± 1.4 and 18.5 ± 7.2 respectively. The mean ± SD of the LKA (°), ABC (%) and SC (°) were 21.4 ± 5.3, 45.9 ± 10.6 and 9.2 ± 1.1 respectively at their final follow-up. Burst fractures (type A4) reported significantly higher rates of treatment failure. Risk factors for non-operative treatment failure were age, BMI and VAS score at the time of injury, initially increased kyphotic angle and compression rate of anterior vertebral height. Conclusion: Vertebral compression fractures (VCFs) are a common type of fracture that involve the thoracolumbar spine and occur when the vertebrae collapse or compress. In patients without neurologic deficit and intact posterior complex conservative treatment is a reliable choice. We found higher rates of operative treatment in osteoporotic patients. Osteoporotic patients and those with increased kyphotic deformity and severe pain at admission may need closer follow-up due to higher risk for treatment failure. Qiang Yang 1 1 Department of Orthopaedics, Tianjin Hospital, Tianjin, China Introduction: This study investigates the clinical efficacy and impact of three conservative treatment approaches - Chinese chiropractic therapy, Schroth therapy, and a combined therapy (Schroth exercise followed by Chinese chiropractic therapy - on various clinical parameters in patients with mild adolescent idiopathic scoliosis – AIS). The objective is to offer clinicians more effective and evidence-based treatment options for managing mild AIS. Material and Methods: This study is a prospective randomized controlled trial involving 60 patients with mild adolescent idiopathic scoliosis (AIS), recruited from the First Spine Department of Tianjin Hospital between May 2022 and July 2023. Participants were randomly assigned to one of three groups (n = 20 each) using a random number table. The first control group received Schroth therapy, the second control group underwent Chinese chiropractic therapy, and the observation group received a combined therapy(Schroth exercise followed by Chinese chiropractic therapy. Participants attended hospital sessions twice a week for 24 weeks. Due to poor compliance, two participants withdrew, leaving a final sample of 58 cases. The first control group (n = 19) had an average session duration of 90 minutes, the second control group (n = 19) 30 minutes, and the treatment group (n = 20) 120 minutes per session. Pre- and post-treatment outcomes were assessed, including the Cobb angle, angle of trunk rotation (ATR), coronal alignment (CAL), clavicle angle (CA), pelvic obliquity (PO), sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), apical vertebral rotation (AVR), and quality of life using the SRS-22 questionnaire. Statistical analysis was performed using SPSS 25.0. Paired t-tests were applied for within-group comparisons, while one-way ANOVA was employed for between-group analyses. Data were presented as mean ± standard deviation (X ± S), and categorical variables were evaluated using the chi-square test (χ 2 ). Statistical significance was set at p < 0.05. Results: (1)Coronal Plane Parameters: after the intervention, the mean primary curve Cobb angle decreased by 4.21° in the first control group, 4.45° in the second control group, and 5.21° in the treatment group. Significant reductions were observed within each group pre- and post-intervention (p 0.05). In terms of ATR, the first control group showed a reduction of 2.1°, the second control group 3.7°, and the treatment group 3.6°, with significant improvements within each group (p < 0.05), but no significant differences between the groups. Improvements in coronal alignment (CAL) and clavicle angle (CA) were not statistically significant across all groups. However, the treatment group showed significant improvement in pelvic obliquity (PO) post-intervention (p 0.05). In the thoracic kyphosis (TK) parameter, the second control group demonstrated a mean reduction of 4°, with a significant difference between pre- and post-intervention values (p < 0.05); (3) Apical Vertebral Rotation (AVR): the mean AVR reduction was 0.48° in the first control group, 0.37° in the second control group, and 0.45° in the treatment group. Significant within-group differences were observed (p 0.05); (4) SRS-22 Questionnaire: the total score and self-image subscore of the SRS-22 questionnaire showed significant improvements in all three groups post-intervention (p 0.05); (5) Efficacy Rates: the treatment group had a cure rate of 35% and an overall efficacy rate of 90%. The first control group reported a cure rate of 21% and an overall efficacy rate of 79%, while the second control group had a cure rate of 21% and an overall efficacy rate of 84%. No statistically significant differences were observed between the groups regarding overall efficacy (p > 0.05). Conclusion: This 6-month trial assessed the effects of combined Chinese chiropractic therapy and Schroth therapy for mild adolescent idiopathic scoliosis (AIS). The combined therapy showed greater reduction in Cobb angle, vertebral rotation, and pelvic obliquity, along with improved treatment efficacy and patient satisfaction. However, no statistically significant differences were found between the groups, highlighting the need for long-term follow-up to assess sustained effects. Early intervention with the combined therapy is recommended to optimize outcomes and enhance the quality of life for AIS patients. Catherine Olinger 1 , Emma Bechler 1 , Kristina Rossmiller 1 , Jill Corlette 1 , Natalie Glass 1 1 University of Iowa, Iowa City, United States Introduction: This retrospective study aims to examine the impact of Patient Controlled Analgesia (PCA) versus non-PCA pain control practices on opioid consumption, pain control, and patient satisfaction in spine surgery patients. The study encompasses the COVID-19 pandemic-induced staff shortage and its influence on pain management practices and outcomes, specifically regarding the efficacy of self-administered pain relief in accommodating this issue. Study Design: This was a retrospective cohort study. The timeline of this study began prior to the onset of COVID-19-induced staff shortages (Jan 1, 2018) and extended to December 8, 2023. Participants: The study included adults aged 18 and older who underwent one of four types of spine surgeries: anterior cervical discectomy and/or fusion, posterior cervical fusion, posterior thoracic/lumbar fusion, and laminectomies/discectomies. Patients received postoperative pain management through PCA or non-PCA. Exclusion criteria included allergies to opioids, spinal procedures outside of the four categories, and age < 18. Methods: Total opioid consumption (morphine milliequivalents, MME), VAS pain scores (peak and average), length of stay and adverse reactions to opioid use were abstracted from electronic health records. The primary outcomes included total opioid consumption as well as peak and average VAS pain scores during the first 24 hours post-surgery. Results: We will compare total MME and VAS scores between groups using the Wilcoxon Rank Sum test. Chi-square tests will be used to compare the proportion of patients utilizing PCA and the proportion reporting satisfaction with pain management between patients undergoing surgery at preoperative and postoperative time points. Analyses will be repeated in groups stratified by surgery type in a series of subgroup analyses. Conclusions: We hypothesized that there would be an increase in use of PCA following the COVID-19 staff shortage compared with prior. Additionally, we hypothesized patients using PCA vs non-PCA would consume significantly less total MME during the first 24 hours following surgery but have similar levels of satisfaction with pain management. PCA allows patients to self-administer pain relief, reducing the need for constant staff intervention. Non-PCA practices face more significant delays in manual analgesic administration and pain assessment given staffing shortages. Lucas Queiroz Mendes 1 , Lucas Pires Martins Ferreira 1 , Matheus Augusto Ferreira Rocha 1 , Anderson Dias 1 , Leonardo Franco Pinheiro Gaia 1 , Douglas Abdalla 1 , Rafael Gonçalves Da Cruz 1 , Claudio Kenji Arakaki Carvalho 1 , Andrea Gasparina 1 , Dernival Bertoncello 1 1 Federal University of Triângulo Mineiro, Uberaba, Brazil Introduction: Around 60% to 80% of the adult population may experience low back pain at some point in their lives. In this aspect, facet syndrome, which is the condition of osteoarthritis with facet degeneration associated with pain, is a pathology that is frequently observed in the population. Currently, facet denervation procedures are used as a diagnostic and therapeutic measure. Among these, solutions with an osmolarity greater than 1000 mOsm/L stand out, such as 25% dextrose in a 1:1 dilution with 1% xylocaine and 5% phenol, which act as neurolytic agents. The present study aims to compare the results obtained by patients with lumbar facet syndrome undergoing phenolic denervation (PD) and 25% dextrose (DD). Material and Methods: A retrospective study was carried out with 102 patients with lumbar facet syndrome, 51 of whom underwent PD and 51 who underwent DD. The age of patients undergoing PD ranged between 27 and 84 years, with 21 men and 30 women. The age of patients undergoing DD varied between 24 and 81 years, with 13 men and 38 women. 2 ml of a solution of the drugs chosen for denervation of the facet joint was applied to the facet joint. All patients responded to an electronic questionnaire after the procedures. The results were evaluated using the Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI). The stipulated confidence level was 95%. Results: Among the 102 patients evaluated, the average ODI of those undergoing PD was 45.2 and the median was 40. Those undergoing DD had a mean ODI of 40.2 and a median of 38. Furthermore , the classification of all patients by the ODI was distributed as follows: 13% with minimal disability (DD = 7/PD = 6), 41% with moderate disability (DD = 19/PD = 23), 27% as severe disability (DD = 17/PD = 11), 14% as invalid (DD = 7/PD = 7) and 5% as restricted to the bed (DD = 1/PD = 4). The T test showing that there are no statistically significant differences between the two techniques. The VAS of the DD group divided into 25 patients in the mild pain group, 17 patients in the moderate group and 9 patients in the intense group. The mean was 3.5 and median 3. The PD group had 13 patients classified in the mild group, 34 patients in the moderate group and 4 patients in the intense group. The mean was 4.1 and median 4. The Wilcoxon test was used with p > 0.05 (0.1153), concluding that there was no statistically significant difference between the PD and DD groups according to the VAS of Pain. Conclusion: Treatment of facet syndrome with PD or DD showed similar results, with no statistically significant differences. Thus, it is inferred that both techniques, when well indicated, can be used to improve the quality of life of patients with low back pain, in order to alleviate pain symptoms with a minimally invasive technique, low cost and with a low rate of complication. Juan Lourido 1 , Miuvaan Shujau 2 , Thihnan Solih 2 , Juman Rasheed 2 , Thooba Saeed 2 1 TreeTop Hospital, Neurosurgery, Hulhumale, Maldives , 2 TreeTop Hospital, Medicine, Hulhumale, Maldives Standardization of treatment after surgery is helpful to objectively evaluate and compare outcomes as well as to identify problems early. Regarding postoperative pain, the difficulty to differentiate objective and subjective factors makes the optimization of treatment challenging. Pain assessment using a formulation of the type “Please tell me how much pain you have, from one to ten” is used commonly by healthcare workers. The use of a gliding scale (visual analogue scale, VAS) has more robust scientific support. We enrolled 25 consecutive patients who underwent scheduled spine surgery for a pilot study. All patients follow the same standard pain medication protocol after surgery. A previous retrospective study of our patients presented in the past, observed on 139 consecutive patients the protocol to be safe and sufficient in our setting, with no opioids needed. In order to simplify the design regarding ethical considerations, no changes to the treatment are involved. Patients are randomized for pain assessment using one of the two modalities (VAS or direct questioning) at 3 points> before administration of medication / at an early phase after administration where no biologic effectiveness is expected/ at peak of expected effect. Before assessing the patient, a nurse and a medical doctor from the treatment team note their perception 1-10 of the pain the patient has, as well as their prediction of what the patient will declare. In this pilot study, (expanding), we present the results comparing the use of two different pain assessment tools, as well as their results compared to the expected pharmacologic effect and the subjective evaluation of experienced health workers. Aziz Bedioui 1 , Marc Zanello 2 , Johan Pallud 2 1 Trauma and Burns Center of Ben Arous, Neurosurgery, Ben Arous, Tunisia , 2 GHU Paris Sainte-Anne, Neurosurgery, Paris, France Introduction: Spinal cord stimulation (SCS) has been proved as an efficient treatment of chronic pain related to failed back surgery syndrome (FBSS). It has also been proven that the delay between pain onset and the implantation of SCS is an important success factor. In this context, the ‘Haute Autorité de Santé’ (French National Authority for Health, HAS) issued in March 2014 its recommendations concerning SCS, stating it should be used for resistant neuropathic pain secondary to surgery after a one-year history. Since no study has investigated the impact of these recommendations on daily practice, we aimed to evaluate the wait time for SCS in FBSS patients before and after the HAS 2014 recommendations. Material and Methods: We conducted a retrospective study of adult patients who underwent a primary SCS implantation for FBSS at the GHU Sainte Anne Hospital four years before and after the HAS 2014 recommendations, so between March 2010 and March 2018. We collected data concerning chronic pain onset, primary follow-up, pain treatment center follow-up, SCS implant, success rates of SCS, and measured the delays between these different steps. We compared the periods before and after the HAS 2014 recommendation issue. Results: Seventy-three patients were included (53% female, 37 before and 36 after 2014 HAS recommendations). In our study, the mean efficacy of SCS for FBSS was 61% ± 22.73%. The mean delay between chronic pain onset and SCS implant was equal to 48.61 ± 45.36 months or 4.07 ± 3.78 years This delay did not significantly shorten after HAS 2014 recommendations (45.33 ± 39.66 vs 51.79 ± 50.67, p = 0.563). The primary follow-up with neurosurgeons was significantly shorter than other specialties (15.74 ± 12.8 vs 36.54 ± 48.93, p = 0.034). The delay after meeting with the implanting practitioners was significantly shorter for patients followed-up in GHU PARIS Sainte Anne PTC (5.01 months ± 3.87 vs 7.17 months ± 3.55, p = 0.046). Conclusion: National HAS 2014 recommendations issue did not change the delay between pain start and SCS implantation. Neurosurgeons referred faster than other physicians and the follow-up in a PTC eased the implantation process. More communication to the general public and to the physicians are required to improve chronic pain management. Ana Clara Cutlac 1 , Fabiano Araújo Faria 1 , Anderson Dias 1 , Leonardo Franco Pinheiro Gaia 1 , Dernival Bertoncello 1 , Andréa Licre Pessina Gasparini 1 1 Federal University of Triângulo Mineiro, Uberaba, Brazil Introduction: According to the Ministry of Health, 70% to 85% of the population will experience disabling back pain throughout their lives. The Global Burden of Disease (2018) classifies low back pain as the main cause of chronic non-communicable diseases in men and women, while neck pain ranks ninth among women and 11th among men. These conditions are frequent causes of work absenteeism and early retirement. Mechanical imbalance of the spine, often caused by incorrect functional postures and attitudes and muscular imbalance, acts as a damaging factor. The objective of this study was to compare the effectiveness of a manual of specific exercises, as a self-care strategy, in relieving pain and improving function in individuals with non-specific mechanical low back and neck pain, in relation to treatment with the same exercises performed in person. Material and Methods: This randomized clinical study included 11 volunteers of both sexes, with a mean age of 51 (± 3) years, allocated into two groups: manual exercise group (GM) and face-to-face group (GP). The intervention period was 4 weeks. The GP performed the exercises in person twice a week, while the GM received instructions to perform the exercises twice a week at home, with follow-up via telephone calls. Both groups were evaluated at the beginning and end of the four weeks. Results: There was no statistical difference between the groups, however both groups demonstrated clinical relevance, classified as moderate to strong, with great applicability for the outcomes of cervical mobility, lumbar mobility and pain. Conclusion: These results highlight the use of the manual of specific self-care exercises as an effective support strategy for patients awaiting care, especially in cases of public service. MCID-based analysis Devender Singh 1 , Eeric Truumees 1 , Ashley Duncan 1 , Morgan Laviolette 1 , Vik Kohli 1 , John Stokes 1 , Matthew Geck 1 1 Ascension, Austin, United States Introduction: Chronic low back pain (CLBP) is one of the most common causes of disability worldwide, often leading to a reduced quality of life and high healthcare costs. Non-operative treatments, such as physical therapy and opioid use, are widely utilized to manage symptoms. However, predicting the likelihood of achieving meaningful improvements in both pain and disability is critical to optimizing patient outcomes. The Minimal Clinically Important Difference (MCID) offers a way to measure clinically meaningful improvements. The aim of this study was to investigate the preoperative factors that predict successful treatment outcomes in chronic low back pain patients using the MCID for disability (ODI) and pain (VAS). Material and Methods: This retrospective analysis included 156 patients with chronic low back pain who underwent non-operative treatment. Logistic regression and random forest models were used to predict the likelihood of achieving MCID for both disability (ODI ≥ 8.71) and pain (VAS ≥ 1.19). Additionally, patient profiles were created based on preoperative characteristics to further explore their impact on outcomes. Results: The study population had an average age of 51 years, with 90% of patients reporting at least one comorbidity. Of the total population, 52% were prescribed physical therapy, while 16% were on opioids pre-intervention. Logistic regression models showed that patients with higher baseline ODI and VAS scores were significantly more likely to achieve MCID, with odds ratios indicating that for every unit increase in baseline ODI, the odds of achieving MCID for disability increased by 8.4% (p < 0.001). Similarly, higher baseline VAS was associated with a higher likelihood of pain improvement (p < 0.001). Preoperative opioid use was negatively associated with achieving MCID for disability (p < 0.001). The success rate for achieving MCID in disability (ODI ≥ 8.71) was 28.96%, while for pain (VAS ≥ 1.19), it was 32.79%. Random forest models provided insights into the variable importance, with physical therapy, baseline ODI, and age being key predictors for successful outcomes. Patient clustering revealed that younger patients with mild symptoms were less likely to achieve MCID, while middle-aged patients with severe preoperative disability and pain had the highest likelihood of success. In Cluster 2, 67.5% of patients achieved MCID for disability and 52.5% for pain, representing the most successful profile. Conclusion: This study confirms the importance of baseline disability and pain in predicting successful outcomes for chronic low back pain patients. Patients with higher preoperative ODI and VAS scores, along with those receiving physical therapy, were more likely to achieve clinically meaningful improvements. Conversely, preoperative opioid use was associated with poorer outcomes in terms of disability improvement. Our findings align with existing literature that injection based, and more aggressive non-operative management should be reserved for more significantly impacted patents. Opioids should be offered sparingly. Clinicians should prioritize physical therapy and tailor interventions based on baseline severity, while limiting the use of opioids to maximize patient recovery. Understanding the patient profiles most likely to benefit from care can help in setting realistic treatment goals and improving clinical outcomes. Saktthi Shanmuganathan 1 , Gabriel Zihui 1 , Joshua k 1 , Sushmita Chandran 1 , Naresh Kumar 2 1 National University Health System, Orthopedics, Spine Surgery, Singapore, Singapore , 2 National University Health System, Singapore, Singapore Introduction: The definitive surgical management in the spectrum of degenerative cervical disc disease associated with myelopathies or radiculopathies, ranges from disc replacements to conventional fusion. Lesser invasive interventions are available for managing these pathologies. Selective nerve root block (SNRB) has been established as a reliable tool for diagnostic and therapeutic purposes for both acute and chronic presentations of symptomatic disc diseases. We hypothesize that the timely and accurate use of foraminal blocks can effectively prevent or delay the need for major surgical intervention in future. Aim: We aimed to: (1) retrospectively analyze the clinical course of the patients who underwent SNRB for symptomatic cervical disc disease, (2) thereby assessing the efficacy and its ability to avoid surgical intervention in future. Methods: We analyzed 182 patients who had undergone SNRB for the last 7 years. We excluded patients (i) with infective and neoplastic pathologies and (ii) patients lost to follow up of minimum 2 yrs or with incomplete data. Data collection included details on demography, clinical symptoms and cause of disease along with standardized outcome scorings (VAS, NDI) radiographic scoring, need for repeated injections and the final outcome of the patient at 2 years (whether ended up with surgery or managing with physiotherapy). All patients who had presented with symptomatic cervical radiculopathy / radiculo-myelopathy with MRI correlation who failed conservative trail for more than 6 weeks to 3 months were given the option of SNRB. A composition 1 - 1.5 ml of steroid (shincort 0.25%) and analgesic (Marcaine 0.5%) was injected into the foraminal and extraforaminal region. Patients were discharged the same day and were followed up at regular intervals of 1month, 3month, 6month, 1 year and up to 2 years. Results: The age group ranges from 33-74 years. 47% of them were males. 92.4% of the patients recovered at the end of 2 years with an average VAS of 2-3 that had improved from an initial score of 6-7. 2.2% ended up in surgery within 2 years of follow up due to worsening of symptoms. The remaining 5.4 % received repeat blocks at the same level due to persisting symptoms for more than 6 months. Conclusion: SNRB has a place is the management of symptomatic cervical degenerative disc disease. Timely intervention with the appropriate composition of injectate can delay if not prevent the need for surgical intervention in patients with cervical disc disease.

Adnene Benammou 1,2 , Roufeida Neffati 1,2 , Seddik Akremi 1,2 , Rebh Hamada 1,2 , Mehdi Bellil 1,2 , Mohamed Ben Salah 1,2 1 University Tunis el Manar, Faculty of Medecine of Tunis, Tunis, Tunisia , 2 Charles Nicolle Hospital, Orthopedic Surgery Department, Tunis, Tunisia Introduction: C1-C2 instability is a frequent complication of rheumatoid arthritis, with a significant morbidity and mortality rate. Surgical treatment is indicated on a case-by-case basis depending on the clinical and radiological presentation. The aim of our work was to compare the functional and radiological results of the stabilization of C1-C2 rheumatoid instability using C1-C2 screw fixation and occipitocervical posterior fixation. Material and Methods: Between 2022 and 2023, We carried out a retrospective study in the orthopedic department of Charles Nicolle Hospital on patients with C1-C2 instability related to rheumatoid arthritis. Eight patients were managed and operated on. Standard radiographs, CT and MRI were performed on all patients preoperatively. We assessed pain according to VAS and neurological deficit according to Ranawat's classification. Radiological findings were assessed on a postoperative CT scan. Results: The mean age of our patients was 55.5 years, with a sex ratio of 0.25. Four patients underwent C1-C2 screw fixation using the HARMS technique (group 1) and four patients underwent OccipitoCervical Fixation (FOC) (group 2). Improvement in mean post-operative VAS was comparable in both groups (G1 = 3.1, G2 = 2.9). According to Ranawat's classification, five patients had neurological improvement, two patients remained unchanged, and one patient had neurological aggravation. Arthrodesis was achieved in all patients belonging to group 2 and 3 patients belonging to group 1. The rate of post-operative complications was higher in group 2, with one case of early sepsis and one case of post-operative deficit. The mean follow-up was 18 months. Conclusion: The most used technique for treating C1-C2 instability is C1-C2 arthrodesis. This technique preserves a considerable physiological range of motion and appears valuable in cases of sub axial overload. Several authors have advocated screw fixation for younger patients with good bone quality. In cases of advanced disease, destruction of the atlantoaxial joint or lateral subluxation, FOC is indicated. FOC can potentially prevent the onset of vertical translocation of the odontoid, a common and potentially fatal phenomenon in cervical RA. FOC has direct and indirect effects on the progression of pannus and on the conditions responsible for its formation (inflammatory phenomena and hypermobility). The timing and the choice of surgical technique in rheumatoid patients is crucial to achieving satisfactory clinical results. The choice of the technique in rheumatoid instability of the spine should take into consideration the age, the bone quality, the disease advancement and the destruction of the atlantoaxial joint or lateral subluxation. David Shin 1 , Brandon Shin 1 , Zachary Brandt 1 , Kai Nguyen 1 , Daniel Im 1 , Muhammad Abd-El-Barr 2 , Wayne Cheng 3 , Olumide Danisa 2 1 Loma Linda University School of Medicine, Loma Linda, United States , 2 Duke University Health System, Durham, United States , 3 Jerry L Pettis Memorial Veterans Hospital, Orthopaedic Surgery, Loma Linda, United States Introduction: Quantitative parameters for diagnosis of congenital cervical stenosis (CCS) have yet to be universally accepted. This study establishes parameters for CCS using computed tomography (CT), assessing the influences of patient sex, race, and ethnicity. Materials and Methods: Measurements of anteroposterior diameter (APD), interpedicular distance (IPD) and neuroforaminal height, width, and area were performed using 1,000 patients between 18 and 35 years of age who were without spinal pathology. CCS was determined as described by Bajwa et al. whereby values two standard deviations below the mean of the measurements conducted in this study were defined as congenitally stenotic. Results: Irrespective of vertebral level, mean anatomic APD, CNFD and IPD measurements were as follows: 14.94 ± 1.99 mm for APD, 6.58 ± 1.45 mm and 6.68 ± 1.45 mm for left and right widths, of 9.30 ± 2.30 mm and 9.25 ± 2.80 mm for left and right heights, 57.0 ± 19.2 mm 2 and 59.5 ± 20.3 mm 2 for left and right areas, and 25.4 ± 1.78 mm for IPD. Irrespective of vertebral level, threshold values for CCS were 10.96 mm for APD, 3.68 mm and 3.78 mm for left and right widths, of 4.70 mm and 3.65 mm for left and right heights, 20.6 mm 2 and 19 mm 2 for left and right areas, and 21.8 mm for IPD. Males demonstrated larger CCS threshold values compared to females for left and right CNFD area at all vertebral levels. African American patients had smaller NFDs and subsequent CCS thresholds at every vertebral level compared to White patients. Conclusions: This study reports measurements across bilateral cervical neuroforaminal measurements and interpedicular distance to establish quantitative thresholds for diagnosis of CCS. APD, CNFD, and IPD measurements, as well as CCS thresholds, were significantly influenced by patient sex, race, and ethnicity. Yoshifmi Kudo 1 , Ichiro Okano 1 , Chikara Hayakawa 1 , Yusuke Oshita 1 , Yushi Hoshino 2 , Soji Tani 1 1 Showa University, Orthopedic Surgery, Tokyo, Japan , 2 Asahi University Hospital, Gifu, Japan Introduction: Dropped head syndrome (DHS) is characterized by chin-on-chest deformity with horizontal gaze difficulty and neck pain. Surgical strategy for DHS has not been established yet. In this study, we investigated the surgically treated DHS patients, and the impact of thoracolumbar spinal alignment on surgical outcomes of the DHS patients. Material and Methods: We included DHS patients who underwent corrective surgery in our facility from 2014 to 2023. Patients were divided in two groups, thoracolumbar (TL) group (SVA > 50 mm, PI- LL > 10°, local kyphosis due to OVF > 30°) and cervical (C) group (others). The surgical outcome of each group was compared. We investigated the spinal sagittal alignment parameters (C2-7A, CSVA, T1slope, SVA, TK, LL, PI, PT), surgical procedures, improvement of horizontal gaze difficulty and complications such as junctional failure and revision surgery. Results: 41 DHS patients (10 male and 31 female, mean age 74.9) were included. The average follow-up periods were 24.7 month. 30 patients underwent cervicothoracic corrective surgery, and 11 patients were treated with thoracolumbar corrective surgery. Group C included 24 patients and group TL 17 patients respectively. In comparison of preoperative sagittal alignment parameters between two groups, significant differences were observed in CSVA (C vs TL, p value; 65.8 vs 73.9,p < 0.05), T1slope(34.4 vs 56.2,p < 0.01), SVA(-26.3 vs 88.6, p < 0.01), LL(56.6 vs 19.9, p < 0.01), PT(21.9 vs 32.6, p < 0.01), PI-LL(-3.3 vs 27.5, p < 0.01). Conversely, there was no difference in C2-7A (-43.4 vs-41.6, p = 0.88), TK (43.1vs43.5, p = 0.98). In group C, all 24 patients underwent cervicothoracic surgery. Although distal junctional kyphosis was observed in 7 patients (29.2%), extension of the fixation was required in only one patient. Severe dysphagia and surgical site infection were seen in one case respectively. Overall surgical outcome of group C was excellent with improvement of horizontal gaze difficulty in all patients. In group TL, 6 patients underwent cervicothoracic surgery resulting in poor outcomes of 5 patients (83%) with distal junctional failure in 2 cases, recurrent of horizontal gaze difficulty in 2 cases, and additional lumbar corrective surgery in one patient. On the other hand, surgical outcomes of 11 cases with thoracolumbar corrective surgery were excellent in 10 cases (91%) with improvement of horizontal gaze difficulty, whereas instrumentation failure occurred in one case. Moreover, significant improvement was observed in C2-7A, CSVA, and T1slope as well as SVA, LL, PT, PI-LL. There was no patient who required additional cervicothoracic surgery. Conclusion: Surgical outcomes of 2 groups were completely different. With our results, thoracolumbar alignment has notable impact on surgical outcomes of DHS patients. It is suggested that DHS patients with thoracolumbar malalignment could be treated with thoracolumbar corrective surgery solely without direct cervical correction. Surgeons should pay more attention to thoracolumbar spinal alignment and take them into consideration to determine surgical plans for patients with DHS. Felipe Gutierrez Pineda 1 , Isabelle Stockman 2 , Esteban Quiceno Restrepo 2 , Asham Khan 2 , Mohamed Soliman 2 , John Pollina 2 , Jeffrey Mullin 2 1 Universidad de Antioquia, Neurosurgery, Medellin, Colombia , 2 University at Buffalo Neurosurgery, Neurosurgery, Buffalo, United States Introduction: The necessity of performing syringomyelia interventions before scoliosis correction is a subject of ongoing debate due to conflicting data. The objective of this study was to systematically review the published literature and perform a meta-analysis to compare the incidence of neurological complications, intraoperative neuromonitoring deterioration, and postoperative loss of correction between patients who underwent syringomyelia intervention prior to scoliosis surgery (SI+SS) and those who underwent spine deformity surgery alone (SS). Material and Methods: Following PRISMA guidelines, we systematically searched databases for studies meeting the following inclusion criteria: 1) studies involving patients with scoliosis associated with syringomyelia that compared SI+SS versus SS alone; 2) patients undergoing any surgical intervention for syringomyelia prior to scoliosis correction; and 3) studies involving any surgical approach for scoliosis correction. We excluded studies not published in English, case reports, review articles, and meeting abstracts. Meta-analysis was conducted using a fixed-effects model when I 2 values were below 50%. For I 2 values equal to or greater than 50%, a random-effects model was used. Results: The meta-analysis included seven studies with a total of 206 patients: 93 (45.1%) in the SI+SS group and 113 (54.8%) in the SS alone group. Analysis revealed that the overall rate of neurological complications was significantly higher in the SS alone group (14.3%) compared to the SI+SS group (8.3%) (p = 0.03). Intraoperative monitoring deterioration rates were comparable between the groups, at 7.6% for SI+SS and 6% for SS alone (p = 0.86). Additionally, there was no statistically significant difference in the rate of loss of correction between the groups, with an odds ratio of 0.81 and a 95% confidence interval of 0.16-4.09 (p = 0.80). Conclusion: Direct spinal surgical correction for scoliosis associated with syringomyelia does not show significant differences in postoperative neurological complications compared to traditional staged surgery with prior syringomyelia intervention. This approach results in comparable rates of intraoperative monitoring alerts and similar rates of loss of correction during follow-up. Max Fisher 1 , Tobi Onafowokan 1 , Anthony Yung 1 , Ankita Das 1 , Lara Passfall 2 , Peter Tretiakov 3 , Melissa Erickson 1 , Paul Park 4 , Andrew Schoenfeld 5 , Andrew Chan 6 , Zorica Buser 7 , Dean Chou 6 , Michael Gerling 7 , Thomas Buell 8 , Nima Alan 9 , Nitin Agarwal 8 , D. Kojo Hamilton 8 , Peter Passias 1 1 Duke University School of Medicine, Division of Spine Surgery, Departments of Orthopaedic and Neurological Surgery, Durham, United States , 2 SUNY Downstate Health Sciences University, Department of Orthopaedic Surgery, Brooklyn, United States , 3 New York Medical College, Valhalla, United States , 4 Semmes Murphy Clinic, Memphis, United States , 5 Brigham and Women's Hospital, Boston, United States , 6 Columbia University, New York, United States , 7 Gerling Institute, Brooklyn, United States , 8 University of Pittsburgh, Pittsburgh, United States , 9 University of California: San Francisco, San Francisco, United States Introduction: Surgical correction of cervical deformity (CD) can restore alignment and function but carries higher risk of complications and subsequent failure. It remains unclear which baseline and postoperative radiographic parameters correlate with improved HRQL metrics and minimized complications. The goal of this study was to determine radiographic alignment targets associated with optimal clinical/functional outcomes in CD Patients. Material and Methods: Operative CD patients with a UIV above C7 and with pre-(BL) and at least 2-year (2Y) postoperative radiographic/HRQL data were included. CD defined as ≥ 1 of: C2-C7 lordosis 35°, segmental cervical kyphosis > 15° across any three vertebrae between C2-T1, C2-C7 SVA > 4 cm, McGregor’s slope > 20°, or CBVA > 25°. An optimal outcome defined as no DJF and meeting Virk et al.’s criteria for good clinical outcome [≥ 2 of NDI < 20 or meeting MCID, mild myelopathy (mJOA ≥ 14), NRS-Neck ≤ 5 or improved by ≥ 2 points from BL]. Regression analysis and Chi-squared Automatic Interaction Detector (CHAID) identified BL and 3-month postoperative radiographic thresholds predictive of an optimal outcome. Results: 340 patients met inclusion criteria (Age = 57.5 ± 10.8 years, 48% F, BMI = 29.1 ± 6.6 kg/m2, CCI = 0.81 ± 1.2) and underwent surgery (levels fused = 5.0 ± 3.6, EBL = 496 mL, OR time = 277 min). Mean BL radiographic parameters: SS = 35.5°, PT = 18.5°, PI-LL = -0.3°, SVA = 0.1 mm, T2-T12 kyphosis = -37.3°, T1S = 29.2°, C2-C7 lordosis = -6.1°, TS-CL = 29.4°, C2S = 30.7°, cSVA = 29.0 mm, C2-T3 = -10.6°, and C2-T3 SVA = 53.5 mm. Mean BL HRQLs: NRS back = 6.0, NRS neck = 7.3, NDI = 56.3, mJOA = 12.9, and EQ5D = 5.8. At 1Y, 79 patients (23.2%) met optimal outcome criteria, and 55 (16.2%) met criteria at 2-3Y. Regression analysis with CHAID identified these radiographic thresholds predictive of an optimal outcome: BL T1S ≤1 8.3º (OR = 3.2, 95%CI [1.63-6.27], p < .001), 3M T1S ≤ 31º (OR = 16.3, 95%CI [1.94-145.95], p = 0.012), and 3M C7-S1 SVA ≤ 38º (OR = 44.4, 95%CI [4.55-432.22], p = 0.001). Conclusion: This study suggests novel baseline radiographic thresholds and postoperative realignment goals associated with favorable functional/clinical outcomes in patients undergoing surgery for CD. Saihu Mao 1 , Kai Sun 1 1 Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China Introduction: To introduce an integrated instrumentation strategy being termed as the sequential correction technique in the treatment of congenital cervicothoracic scoliosis (CTS). Material and Methods: This study prospectively recruited a consecutive series of patients with CTS-HV who underwent posterior-only HV resection with sequential correction technique. This technique employs multiple rods, each designated for a specific task, to sequentially perform correction maneuvers involving osteotomy closure, proximal convex compression/concave distraction with satellite rod to further improve torticollis correction and adjust overall shoulder balance. Radiographic parameters including segmental scoliosis, T1 tilt, neck tilt, clavicular angle, head tilt and head shift were measured and compared preoperatively, postoperatively and at the latest follow-up. Additionally, any complication occurred intraoperatively and during follow-up would be recorded. Results: This study included 18 cases, comprising 8 females and 10 males, with a mean age of 8.6 ± 3.9 years. All patients had two rods installed on the convex side using screw-hook hybrid technique. 3 patients also had two rods installed on the concave side. The instrumentation systems used included a complete cervical system (3.5 mm) in 2 cases, a complete thoracic system in 15 cases (4.5 mm or 5.5 mm), and a cervical-thoracic hybrid system in 1 case. The deformity parameters, including segmental scoliosis, T1 tilt, neck tilt, clavicular angle, head tilt, and head shift, were significantly corrected from 52.9 ± 8.7°, 23.2 ± 6.5°, 15.0 ± 5.9°, 3.3 ± 1.8°, 6.4 ± 3.6°, and 16.8 ± 11.0 mm preoperatively to 22.4 ± 6.8°, 11.0 ± 4.6°, 5.2 ± 3.4°, 1.6 ± 1.5°, 2.9 ± 1.8°, and 8.1 ± 6.0 mm postoperatively (all p 0.05). One patient experienced dural tear during surgery, one patient experienced Horner's syndrome postoperatively, and three patients experienced severe distal curve progression and underwent revision surgery. No implant-related complications were observed. Conclusion: The sequential correction technique can significantly reduce the difficulty of rod installation, extend the construct proximally and symmetrically to further correct torticollis, disperse the stresses of internal fixation, and achieve higher internal fixation stability. For complicated congenital cervicothoracic scoliosis, sequential correction technique is recommended. Wei Wu 1 , Jianfeng Guo 1 , Feng Li 1 1 Tongji Hospital Attached to Tongji Medical College Huazhong University of Science and Technology (HUST), Department of Orthopaedic Surgery, Wuhan, China Introduction: Adolescent cervical kyphosis would cause serious consequences, and its treatment strategy is controversial. The authors present case series to investigate the safety and efficacy of anterior cervical discectomy and fusion (ACDF) in the treatment of adolescent cervical kyphosis (idiopathic kyphosis, AICK and iatrogenic), and to reflect on distal junctional kyphosis (DJK). Material and Methods: The clinical and radiographic data of 12 teenage patients received ACDF were analyzed retrospectively. Japanese orthopedic association (JOA) score, visual analogue score (VAS) of neck pain, and neck disability index (NDI), C2-C7 cobb angle, kyphosis index (KI), T1 slope (T1S), C2-C7 sagittal vertical axis (C2-C7 SVA) were measured at preoperative, 1 month postoperative and last follow-up. KI were measured at post-traction. Results: No serious complications occurred at all follow-up. Postoperative and last follow-up VAS scores and NDI were less than preoperative (p < 0.05), and JOA scores was greater than preoperative (p < 0.05). Post-traction KI were less than preoperative (p < 0.05); C2-C7 cobb angle, KI of postoperative were less than preoperative (p < 0.05). Postoperative and last follow-up KI were less than post-traction (p < 0.05). C2-C7 cobb angle, and KI of last follow-up were less than preoperative (p < 0.05). There was no statistical differences between postoperative and last follow-up. The changes of T1S and C2-C7 SVA were no statistical difference. 1 case developed DJK postoperatively after 1 year, and the deformity was corrected by using extended fixation. Conclusion: ACDF in the treatment of AICK can effectively correct the cervical curvature and improve their clinical symptoms for good flexible patients. Preoperative cervical traction is an effective auxiliary measure. And the operators should pay more attention to the occurrence of DJK. Luke Jouppi 1,2 , Zaara Rasheed 2 , Anna Gorbacheva 2 , Julius Gerstmeyer 1,2,3 , Donald Davis 1,2 , Nicholas Minissale 1,2 , Cameron Hogsett 1,2 , Mark Kraemer 1,2 , Tara Heffernan 2 , Amir Abdul-Jabbar 1,2 , Rod Oskouian 1,2 , Jens Chapman 1,2 1 Swedish Neuroscience Institute, Seattle, United States , 2 Seattle Science Foundation, Seattle, United States , 3 Ruhr University Bochum, BG University Hospital Bergmannsheil, Department of General and Trauma Surgery, Bochum, Germany Introduction: Cervical corpectomy is performed to treat a wide variety of conditions including trauma, infection, and tumors. Implants such as autograft, allograft, and cages may be used for stabilization after bony resection. The emergence of new graft material and hardware has resulted in the increased utilization of this procedure. This bibliometric analysis aims to explore the temporal progression of cervical corpectomy as a topic in scientific literature with the goal of analyzing trends in publications, citation profiles, publishing countries, authors, keywords, and topics. Methods: Using the Web of Science (WoS) database, data was retrieved on July 26, 2024, using the terms “corpectomy” OR “vertebral body resection” AND “cervical” NOT (“lumbar” OR “thoracic” OR “thoracolumbar”). Excel was used to create the citation analysis and publication trend models, along with the publishing countries and author analysis. Using the bibliometric software VOSviewer™, keyword co-occurrence network visualizations were generated. Results: Overall, 1240 articles were extracted. The number of publications increased more than 25-fold in 1999 with a further exponential rise to 83 publications in 2023. Titanium Mesh Cages (TMCs) have recently become a more frequent topic of interest, while the terms allograft and autograft have decreased. Dysphagia is a commonly cited term and similarly, “complications” has expanded in publication records. The United States of America, China, and Japan are the top publishing countries, with 417, 351, and 98 publications, respectively. Conclusion: This bibliometric analysis on cervical corpectomy in spine surgery offers further insight into the evolving landscape of research, authorships, and publication trends over time. The rise in publications may continue with the future development of technologies. Keywords: Cervical Corpectomy, Bibliometric Analysis, Spine Surgery, Cervical spine fusion Luis Eduardo Carelli Texeira da Silva 1 , Alderico Girão Campos de Barros 1 , Giancarlo Jorio Almeida 1 , Silvia Flores Taracena 1 1 INTO, Spine Surgery, Rio de Janeiro, Brazil Introduction: Rigid cervical kyphotic deformity has a challenging treatment. Adjunctive use of anterior cervical osteotomies can improve sagittal alignment and decrease bleeding and complications. Could anterior osteotomy help in alignment correction and in decreasing neurological and clinical complications? Material and Methods: Retrospective cohort of 7 patients operated on a single institution with average of 26.5 years old (11-64) were analysed between 2014-2023 for: Number of anterior cervical osteotomies, cervical kyphotic correction, cervical spinal vertical alignment (cSVA), C2 Slope, T1 Slope, Neurological function by the modified Japanese Orthopaedic Association scale (mJOA), transfusion rates and complications. Results: Average of 63 months of follow up, 15 levels of osteotomies, an average of 2 levels per patient (1 to 4). Average operation time: 8h 51min (Anterior + Posterior Approaches). Only 2 patients received blood transfusion. Preoperative cSVA (42.3-77 mm), Postoperative cSVA (0.4-37 mm); Preoperative Kyphosis on average 55.1° (19.5-111.8°), Postoperative kyphosis on average 15.05° (2-34°); Preoperative C2 Slope 32.25° (10-47.9°), Postoperative C2 Slope 14° (4.6-23.4°). Preoperative T1 Slope 23° (0-50.2°), Postoperative T1 Slope 17.15° (1.8-40.8°). Regarding neurological function, all patients had some degree of recovery (Preoperative mJOA 13 to postoperative mJOA 16.14 on average). Two patients had durotomies and were treated conservatively. Conclusion: Anterior osteotomies proved to be effective in correcting kyphotic deformity in combination with posterior spinal fusion, reducing blood transfusion and providing neurological improvement. Deng Youwen 1 1 The Third Xiangya Hospital, Changsha, China Introduction: Atlantoaxial dislocation is a severe spinal injury that may lead to neurological deficits and decreased quality of life. The condition can be classified into complete and incomplete dislocations. Traditional treatment methods, including traction and internal fixation, may be inadequate in certain cases. We propose the method of posterior intra-articular release and bone grafting to improve clinical outcomes in dislocated patients. Additionally, this study will explore the application and potential advantages of using autologous bone grafting from the atlas. Material and Methods: This study retrospectively analyzed 25 patients with atlantoaxial dislocation who underwent posterior intra-articular release and bone grafting from 2021 to 2023. Preoperative radiological evaluations were conducted for all patients, and decompression and grafting were performed during surgery. The release strategy involved decompression of the dislocation and grafting in the interlaminar space. Indications included specific types of dislocations and associated neurological symptoms, while contraindications involved severe osteoporosis and infection. Patients were followed up for 12 months postoperatively to assess neurological function, radiological outcomes, and complication rates. Results: All patients successfully completed the surgery, with significant improvements in neurological function scores observed postoperatively (p < 0.01). Radiological evaluations indicated a dislocation reduction success rate of 92% and a graft fusion rate of 88%. The postoperative complication rate was less than 10%, primarily involving postoperative pain and infection. Conclusion: Posterior intra-articular release and bone grafting for atlantoaxial dislocation is a safe and effective surgical approach that can significantly improve patients' neurological function and radiological outcomes. The method of using autologous bone grafting from the atlas provides a new perspective for this treatment, potentially reducing the risk of rejection and promoting bone healing. This technique may become a standard option in managing atlantoaxial dislocation in the future. Lucas Zubillaga 1 , Gareth Rutter 1 , Maria Joseph 1 , Mitchell Hansen 1 1 John Hunter Hospital, Newcastle, Australia Introduction: Anterior cervical corpectomy and fusion (ACCF) is a vital surgical technique employed to address complex pathologies affecting the anterior column of the cervical spine. This procedure is indicated for various conditions, including degenerative diseases that lead to significant structural deformities or myelopathy, as well as infections and tumors that involve the anterior elements of the spine. Additionally, ACCF is effective in cases of ossified posterior longitudinal ligament and failed previous cervical fusion or arthroplasty. In this study, we aim to critically analyze our experience with ACCF, placing particular emphasis on the surgical technique utilized, the indications for the procedure, and strategies for avoiding complications. By reviewing our practices and outcomes, we hope to contribute to the understanding of ACCF as a treatment option, ultimately contributing to a deeper surgical comprehension of this complex procedure. Materials and Methods: We conducted a retrospective review of all patients who ACCF, whether single or multi-level, performed by a single surgeon at a public hospital over the past five years. Our analysis focused on the surgical technique employed during these procedures. We evaluated both clinical and radiological outcomes pre-treatment and postoperatively. Additionally, we analyzed the specific indications for surgery and any complications associated with each condition treated. We retrieved surgical video records and images to illustrate the key steps of the surgical technique, providing a comprehensive overview of our approach to ACCF. Results: A total of 12 patients were included in the study, with a mean postoperative follow-up period of 36 months. Trauma emerged as the predominant indication for ACCF, accounting for approximately 35% of cases, primarily involving unstable fractures that impacted the posterior elements of the spine. Degenerative disease was a common indication, comprising around 25% of the cohort and presenting with significant myelopathy or structural deformities. Infection was also an important cause, representing approximately 25% of cases, while ossified posterior longitudinal ligament (OPLL) was identified in 15% of patients. The reoperation rate was low, occurring exclusively in cases related to infection that resulted in progressive deformity. Approximately 70% of patients returned to their normal activities and work within the follow-up period. Conclusions: ACCF remains a robust surgical option for managing complex cervical spine pathologies. Success in this procedure hinges on a comprehensive understanding of surgical anatomy and meticulous attention to technical factors. Tailoring the technique to each individual patient is essential for achieving optimal outcomes. Careful analysis of preoperative imaging and precise measurements are vital in guiding the selection of appropriate implant sizes, but the surgeon should be ready to adapt his plan to different scenarios. The decision to incorporate additional posterior fixation should be made judiciously, particularly in cases involving infection or posterior column compromise, to mitigate the risk of reoperation. Our experience reinforces the importance of mastering this versatile surgical technique, which equips surgeons to effectively address a wide array of spinal pathologies. By refining our approaches and sharing insights, we hope to contribute to improve patient care and surgical outcomes in complex cases. Juliette Gammel 1 , Jason Silvestre 1 , Gabriella Rivas 1 , John Glaser 1 , Charles Reitman 1 , James Lawrence 1 , Robert Ravinsky 1 1 Medical University of South Carolina, Charleston, United States Background Context: Although medical schools now have seemingly equal representation of males and females, there remains a significant disparity in the number of females in surgical specialties including orthopaedics and neurosurgery. Addressing sex disparities among spine surgeons may help promote more effective spine care delivery in the United States (US). Purpose: This study assessed the representation of female spine surgeons in the US Medicare database. Study Design/Setting: Retrospective cross-sectional study of spine surgeons performing anterior cervical discectomy and fusion (ACDF) surgery in the Medicare Provider Utilization and Payment Dataset during 2013-2021. Patient Sample: N/A. Outcome Measures: The total representation of female spine surgeons performing ACDF, their procedural volumes, and reimbursements compared to male cervical spine surgeons. Methods: The Medicare Provider Utilization and Payment Dataset was used to identify neurosurgical and orthopaedic surgeons performing ACDF surgery from 2013-2021. The dataset was linked to the Medicare National Downloadable File to determine hospital affiliations and medical training details. All hospitals included were queried to determine association with residency or fellowship training programs. Results: There were 2,492 surgeons who performed at least eleven ACDFs over the study period accounting for 139,456 total cases. Of these, there were 58 female spine surgeons (2.3%) who performed 2,733 cases (2.0%). The percentage of female surgeons increased from 0% (0/1,124) in 2013 to 1.8% (12/651) in 2021 (p < 0.001). The average volume of ACDFs performed by females (16.8 ± 3.6) was similar compared to males (17.2 ± 7.6; p = 0.712). Among female surgeons, 13.9% were affiliated with a hospital which had an orthopaedic or neurosurgery residency program compared to 11.8% of male surgeons (p = 0.697). Mean standardized reimbursement by Medicare for ACDFs was $1,304, with no difference between female and male surgeons during the study period (p = 0.145). There were no significant differences in the beneficiary demographics between male and female surgeons, except for in 2021 where female surgeons saw a higher proportion of female patients (56.8 ± 2.7% vs 55.0 ± 4.7%, p = 0.043). Conclusions: Despite some progress observed over the study period, profound sex disparities persist among practicing spine surgeons performing ACDF. Strategies are needed to increase the number of female medical students and residents interested in a career in spine surgery. 1 Dong Hun Kim, 2 Jung Woo Hur, 2 Jae Taek Hong 1 Bucheon St. Mary's Hospital, The Catholic University of Korea, Seoul, South Korea, 2 Eunpyeong St. Mary's Hospital, The Catholic University of Korea, Seoul, South Korea Introduction: Retro-odontoid pseudotumor (ROP), also known as pannus, is a non-neoplastic soft tissue mass adjacent to the odontoid process of C2, which can cause cervicomedullary compression. There are two distinct types of ROP - granulation, and cystic type. However, to date, there is no known research regarding guidelines based on these types of ROP or the clinical and radiological outcomes after surgery. The purpose of this study is to investigate the difference between C1-2 instability with ROP and without ROP, to analyze the imaging characteristics and difference between ROP with cyst and granulation, and to clarify the regression patterns of pannus depending on the pathology and find adequate surgical modalities. Material and Methods: The patients with C1-2 instability with or without ROP between 2007 and 2023 were enrolled for this study. Exclusion criteria are 1) previous history of high cervical spine surgery, and 2) insufficient follow-up data. The analysis included patient details such as age, sex, Japanese Orthopaedic Association (JOA) score, as well as radiographic parameters including atlanto-dens interval (ADI), difference in atlanto-dens interval between flexion and extension (ΔADI), C1-2, C0-1, C2-7 angle and range of motion (ROM), presence of dens erosion, C1-2 facet arthritis, and retro-odontoid pseudotumor (ROP) calcification, as well as ROP thickness. Using the data above, radiological analysis was conducted to compare the ROP-positive group with the ROP-negative group, as well as between patients with cystic ROP and granulation ROP. Results: In the demographic analysis comparing C1-2 instability patient groups with and without ROP, age was found to be higher in the group with ROP. However, no significant differences were observed based on sex or etiology. In the radiologic analysis, the ROP-negative group showed significantly larger ADI and C2-7 ROM, whereas the ROP-positive group exhibited more prominent prevalence of dens erosion. When comparing ROP patients divided into cyst and granulation groups, the cyst group had a higher prevalence of Os odontoideum, while the granulation group had more cases of cervical spondylosis, rheumatoid arthritis (RA), and enthesopathy. The cyst group demonstrated larger ADI and C1-2 ROM; however, pannus calcification was observed in a higher proportion of cases in the granulation group. Interestingly, immediate postoperative ROP thickness notably decreased in the granulation group compared to the cyst group (Table 3). However, at 3 months after surgery, the degree of change in ROP thickness dramatically increased in the cyst group, while it gradually increased in the granulation group. Conclusion: Because ROP is characterized by a low prevalence rate, it currently lacks clearly defined clinical significance. In this study, we analyzed the radiological measurements in patients with C1-2 instability who had ROP and identified the patients’ characteristics. Through our research, it was discovered that adequate stabilization is critical for retro-odontoid pseudotumor regression. In addition, it was found that the granulation group can achieve early pannus regression after vertical reduction or stabilization, while the cyst group may show a tendency of delayed regression postoperatively. If ventral cystic compression is severe, direct cyst removal may be necessary, whereas patients with the granulation type could be adequately treated with indirect decompression.

Jie Wang 1 , Zihao Ding 1 , Yong Hai 1 1 Beijing Chaoyang Hospital, Capital Medical University, Orthopedic Surgery, Beijing, China Introduction: To explore the long-term clinical efficacy of lumbar inter-laminar Coflex dynamic stabilization in the treatment of lumbar spinal stenosis in the middle-aged and elderly patients. Material and Methods: The clinical data of 33 patients who underwent posterior fenestration decompression combined with Coflex dynamic stabilization in the Department of Orthopedics, Beijing Chaoyang Hospital, Capital Medical University from January 2010 to December 2012 due to lumbar spinal stenosis were retrospectively analyzed. A total of 33 middle-aged and elderly patients with lumbar spinal stenosis who underwent PLIF surgery and matched their baseline data in age, gender, bone density, symptom duration, symptom severity, decompression segment, unilateral/bilateral decompression, intervertebral foraminal height (IFH), intervertebral space height (ISH), and lumbar range of motion (ROM) during the same period were selected as controls. The visual analogue scale (VAS) for low back and leg pain, lumbar Oswestry disability index (ODI), lumbar Japanese Orthopaedic Association (JOA) score, IFH and ISH of the surgical segment, lumbar ROM of the surgical segment and adjacent segments, and adjacent segment degeneration (ASD) of the two groups were observed before surgery and 1 month, 1 year, and 10 years after surgery. The intraoperative and postoperative complications were recorded. Results: The operations of both groups of patients were successful, and the operation time, intraoperative blood loss, and hospitalization period of the Coflex group were significantly lower than those of the PLIF group (p 0.05); 10 years after surgery, IFH, ISH, and adjacent segment ROC were lower than those in the PLIF group (p < 0.05) ); the ROC of the surgical segment in the Coflex group gradually decreased 1 month, 1 year, and 10 years after surgery (p < 0.05); the long-term ASD incidence and revision rate in the Coflex group were significantly lower than those in the PLIF group (p < 0.05). There was no statistically significant difference in the incidence of surgical complications between the two groups. Conclusion: Lumbar interlaminar Coflex dynamic stabilization is safe and effective for long-term follow-up of lumbar spinal stenosis in the elderly. It retains the mobility of the surgical segment. Although the IFH and ISH of the surgical segment gradually decrease, it is often asymptomatic. Long-term follow-up shows significant relief of low back pain. The long-term follow-up of lumbar interlaminar Coflex dynamic stabilization is significantly better than PLIF in reducing the incidence of ASD and revision rate. Key words: Inter-laminar Coflex; Posterior lumbar interbody fusion; Degenerative lumbar diseases; Long-term follow-up; Efficacy Vinicius de Meldau Benites 1 , Aécio Rubens Dias Pereira Filho 2 , Vinicius Santos Baptista 1 , Matheus Galvão Valadares Bertolini Mussalem 1 1 Universidade Federal de São Paulo, São Paulo , 2 Instituto de Acessos à Coluna Aécio Dias, São Paulo, Brazil Objective: To compare intraoperative and short-term postoperative outcomes of patients with recurrent lumbar disc herniation undergoing ALIF Stand-Alone, ALIF 360°, or Arthroplasty. Methods: This retrospective cohort study was conducted at a single center from August 2019 to January 2024. Inclusion criteria included patients over 18 years diagnosed with recurrent lumbar disc herniation undergoing ALIF Stand-Alone, ALIF 360°, or Arthroplasty. Exclusion criteria were incomplete data or other indications. Data collected included demographics, surgical specifics (procedure type, operated levels, graft type, incision type), and clinical outcomes (intraoperative morbidity and short-term postoperative outcomes). Results: Sixty-five patients were evaluated. No intraoperative complications occurred in any group. Average operative times were 165.8 ± 61.72 minutes for ALIF Stand-Alone, 236.25 ± 46.3 minutes for ALIF 360°, and 98.43 ± 45 minutes for Arthroplasty (p < 0.0001). The average postoperative hospital stay was 2.46 ± 1.14 days, with no significant difference between groups (p = 0.515). Postoperative complications were minimal: one surgical site infection in the ALIF Stand-Alone group (p = 0.444) and four instances of sympathetic changes (p = 0.477). Conclusion: There was no significant difference in intraoperative morbidity, short-term postoperative outcomes, or length of stay among the three groups. All techniques demonstrated good results with low morbidity and short hospitalization times post-procedure, suggesting that the choice of technique should be based on the surgeon's experience and the patient's condition and preferences. Ashley Frei 1 , Hania Shazad 2 , Josh Callaway 2 , Wyatt Vander Voort 2 , Rolando Roberto 2 , Yashar Javidan 2 , Safdar Khan 2 , Eric Klineberg 2 , Hai Le 2 1 Wayne State University School of Medicine, Detroit, United States , 2 UC Davis Medical Center, Sacramento, United States Introduction: Isthmic spondylolisthesis (IS) most often occurs at the lumbosacral junction and may require surgical intervention to restore spinal stability and improve back and leg symptoms. Surgical treatment can be accomplished with either an anterior, posterior, or combined lumbar approach. There are currently limited large-scale studies comparing these different surgical approaches for treatment of IS. This study aims to compare the 90-day medical and surgical complications of anterior, posterior, and combined lumbar fusion for adults with single-level IS. Material and Methods: Deidentified patient data was obtained through the PearlDiver database using relevant ICD and CPT codes from 2015 to 2022. Patients ≥ 18 years old with single-level IS [ICD-9 756.11, ICD-9 756.12, ICD-10 Q76.2] who had undergone either anterior lumbar interbody fusion (ALF) [CPT-22556, CPT-22558, CPT-22586], posterior lumbar fusion (PLF) [CPT-22630, CPT-22612], or combined anterior-posterior lumbar fusion (CLF) [CPT-22633, CPT-22634] were evaluated. Patients undergoing more than one level lumbar fusion were excluded [CPT-22614, CPT-22632, CPT-22585]. Medical and surgical complications were compared across cohorts up to 90 days postoperatively. Results: Of the 35,496 patients who underwent lumbar spinal fusion for IS, 8,365 (23.6%) had ALF, 12,276 (34.6%) PLF, and 14,855 (41.8%) CLF. At 90 days postoperatively, multivariate analysis controlling for demographics, tobacco use, and obesity reveals that the odds of readmission were significantly lower in patients who underwent PLF (OR 0.67, p < 0.01) or CLF (OR 0.50, p < 0.01) compared to the ALF cohort. There was a significantly higher odds of developing sepsis in patients undergoing PLF compared to ALF (OR 1.58, p < 0.05). Compared to ALF, the CLF cohort had higher odds (OR 1.12, p = 0.01) of developing wound complications. There was not a significant difference in the rate of urinary tract infection (UTI), postoperative hematoma, pulmonary embolism, cardiac arrest, cauda equina syndrome or reoperation at 90 days between the PLF or CLF cohorts compared to the ALF cohort (p-value > 0.05). Conclusion: Among adult patients with IS undergoing single-level lumbar fusion, 34.6% had posterior surgery while 41.8% had combined anterior-posterior surgery. Compared to the anterior approach, patients undergoing posterior or combined approaches had lower 90-day readmission rates. However, patients undergoing posterior surgery had higher odds of developing sepsis, while patients undergoing combined surgery had higher odds of developing wound complications. These differences in complication profile may help surgeons in surgical decision making on which approach to consider in their patients with IS. Justyna Fercho 1 , Radosław Trzciński 2 , Maciej Mielczarek 3 , Piotr Zieliński 2 , Tomasz Szmuda 2 1 Emergency Department, Medical University of Gdańsk, University Clinical Centre in Gdańsk, Gdańsk, Poland , 2 Neurosurgery Department, Medical University of Gdańsk, University Clinical Centre in Gdańsk, Gdańsk, Poland , 3 Neurosurgery Department, The Stanisław Staszic Specialist Hospital in Piła, Piła, Poland Introduction: Anterior lumbar interbody fusion (ALIF) retroperitoneal standalone surgery is recommended for a variety of patients with L5/S1 foraminal stenosis. ALIF procedure allows to restore the disc and also foraminal height. The purpose of this study was to assess the radiological changes in foraminal space and to evaluate the clinical results in terms of leg pain relief and radicular claudication. Material and Methods: All 51 patients underwent L5/S1 ALIF procedure with direct root decompression from retroperitoneal approach at two institutions (single surgeon series). During the procedure a detailed microscopic direct debulking foramen surgery was performed. Foraminal size was measured on accessible pre- and postoperative MR and/or CTs and compared. Self-reported changes regarding leg claudication and leg pain in 3-6 months follow-up were the primary end-points in the study. Pre- and postoperative foraminal width, height and surface were compared. Results: Only 34 of 51 patients (67%) presented with radicular pain at admission. Of those, 13 (38%) presented with radicular claudication. The surgery decreased mean leg pain from 6,3 to 4,1 in NRS numeric scale. Leg claudication improved in 4 of 13 patients (31%) and remained unchanged in the rest (69%) after 3-6 months. However, among patients without radicular symptoms before the surgery, two patients (2 of 17, 6%) developed radicular pain and one patient (1 of 34, 3%) L5 paresis following ALIF procedure. In these two patients a lordotic cage was used and the foramen was narrowed by superior articular S1 process. We observed week correlations of foramen size changes (incl. width, height and surface) with clinical results of radicular pain and radicular claudication, suggesting the role of direct over indirect decompression during ALIF. Conclusion: The technique of indirect decompression during ALIF could fail when lordotic cages are used. Superior articular process of S1 vertebrae could unintentionally narrow the foramen and infringe L5 root. Based on our experience, in case a lordotic cage is planned to restore sagittal balance, the use of larger implants is advised. Surgeon should pay more attention to direct decompression of spinal foramen during ALIF procedure. The technique of direct decompression should include peculiar L5 osteophyte removal and should be evolved by new microscopic techniques. Thiago Scharth Montenegro 1 , Katherine Corso 2 , Katherine locke 3 , Glenn Gonzalez 4 , Kevin Hines 4 , Ellina Hattar 4 , Sara Thalheimer 4 , Caio Matias 4 , Philippe Scharth Montenegro 1 , Aline De Quadros Teixeira 1 , Mohamed Abouelleil 1 , Lucca Palavani 5 , Srinivas Prasad 4 , Jack Jallo 4 , Joshua Heller 4 , Ashwini Sharan 4 , James Harrop 4 1 Michigan State University, Grand Rapids, United States , 2 Johnson & Johnson, New Brunswick, United States , 3 Drexel University, Philadelphia, United States , 4 Thomas Jefferson University, Philadelphia, United States , 5 Max Planck University Center, Indaiatuba, Brazil Study Design: This is a retrospective cross-sectional study. Objective: This study aims to examine the overall trends of lumbar fusion and arthroplasty over time among United States (U.S.) commercially insured enrollees. Summary of Background Data: The early 2000s brought a new surgical option to traditional spinal fusion techniques for the treatment of symptomatic lumbar degenerative disc disease with the FDA approval of the artificial disc to the United States (U.S.) market. Material and Methods: A retrospective cross-sectional study of IBM MarketScan Commercial Claims and Encounters Database was utilized to identify patients 19–64 years of age with lumbar disk arthroplasty (LDA) or lumbar fusion (ALIF) between 2005 to 2018. Elective spine patients with 1-2 level treatment were included. Patient-level procedure counts were projected to the U.S. commercially insured population. Yearly incidence and percent of characteristics were estimated per procedure and the percent change was used to summarize changes over time. Logistic regression models were used to compare the characteristics of patients who underwent fusion versus arthroplasty. Results: From 2005 to 2018, the projected count and incidence of ALIF increased, while LDA declined. In 2018, the estimated incidence of procedures was 0.4 per 100,000 and 16.3 per 100,000 enrollees, LDA and ALIF, respectively. Compared to arthroplasty, ALIF patients were older, more comorbid, female, diagnosed with stenosis/myelopathy or spondylosis, but had less outpatient procedures and Degenerative Disk Disease without myelopathy. The percentage of patients with high comorbidity scores (> 2) and outpatient surgery increased over time for all procedures. Conclusion: This illustrates that over the past decade LDA has not been well adopted and has continually declined demonstrating a trend on motion-preservation techniques on the lumbar region. Key Words: Lumbar fusion, Arthroplasty, Total Disc Replacement

Junyu Li 1 , Chang Liu 1 , Zhuo Ran Sun 1 , Yongqiang Wang 1 , Miao Yu 1 , Weishi Li 1 , Yan Zeng 1 1 Peking University Third Hospital of China, Beijing, China Introduction: Distal junctional problem (DJP) is a common complication after thoracolumbar spine surgery, which brings physiological and psychological burdens to patients and has become a hot topic in current research. However, there is no consensus on how to determine the surgical strategy and postoperative orthopedic correction of sagittal parameters according to patient characteristics. Therefore, we would like to explore the risk factors of DJP after thoracolumbar spine surgery and prevent its occurrence, in terms of sagittal parameters, fusion stage selection and perioperative Rousouy typing, through this study. Material and Methods: Post-thoracolumbar spine patients in our hospital from 2006 to 2022 were retrospectively analyzed and from them 103 patients who continuously participated in this study were selected. The mean age of the post-thoracolumbar DJP group was (65.21+8.21) years, of which 14 were females and 5 were males. The mean age of the control group was (64.23+9.43) hairs, of which 63 were females and 21 were males.We compared the preoperative, postoperative and follow-up CL, PrTK, TK, TKmax, TLK, GK, LL, PI, SS, PT, SVA, TPA, and preoperative and postoperative lowest instrumented vertebra (LIV) to posterior superior sacral margin distance from the plumb line (DLS), the preoperative Roussouly typing, and whether correction of postoperative Roussouly typing is desirable in the DJP group and the control group. And we compared the effect of LIV on the SSV, FLV, LEV, and sacral and whether residual vertebral body slippage remained postoperatively on the occurrence of DJP, respectively. Results: As far as sagittal parameters are concerned, smaller postoperative PrTK and DLS and larger follow-up TKmax are risk factors for DJP, while whether correction of postoperative Roussouly typing is desirable are strongly associated with the DJP (p = 0.001). In addition, we found that the probability of DJP was small when the LIV was located in the FLV and LEV (p = 0.038; p = 0.049), and there was no significant difference when it was located in the SSV (p = 1.000) and sacrum (p = 0.357). In contrast, postoperative residual vertebral body slippage resulted in a higher incidence of DJP (p < 0.001). Conclusion: The results of postoperative sagittal parameter correction, LIV selection, the presence or absence of postoperative residual vertebral body slippage, and the desirability of correction of postoperative Roussouly typing are closely related to the occurrence of postoperative DJP in the thoracolumbar spine. Based on this result, prudent selection of the LIV position according to the patient's own characteristics, correction of the presence of postoperative residual vertebral body slippage, and correction according to the Roussouly fractionation theory are beneficial to the prevention and reduction of postoperative DJP in the thoracolumbar spine and have prospective significance. Olivier Ricart 1 , Jean Yves Lazennec 2 , Jean Patrick Rakover 3 , Marc-Antoine Rousseau 4 1 Hôpital Kirchberg Luxembourg, Spine Surgery, Orthopaedics, Luxembourg, Luxembourg , 2 Hôpital Pitié Salepétrière, Orthopaedics, Spine Surgery, Paris, France , 3 Clinique du Pré, Spine Surgery, Le Mans, France , 4 Hôpital Bichât Beaujon, Orthopaedics and Traumatology, Paris, France Introduction: The purpose of the present study is to evaluate the clinical and radiographic outcome in patients operated with C- ESP. C-ESP is a cervical disc prosthesis fundamentally different from that of the devices currently used in the cervical spine. This viscoelastic prosthesis is made of titanium endplates and a PCU cushion allowing 6 degrees af freedom including shock absorption with a free center of rotation during motion. Study design: This is a monocentric prospective noncomparative study. Patient sample: Ninety six consecutive patients were enrolled in the study so far. Mean age was 52 years. Material and Methods: Disc replacement for the treatment of patients with symptomatic cervical radiculopathy at 1, 2 or 3 levels from C3 to T1. Neck Disability Index (NDI), visual analog scales (VAS) assessing neck and arm pain, Short Form 12 Health Survey (SF-12), safety, and radiographic outcomes were assessed preoperatively, at 6 weeks and 12, 24 months and 4, 6, 8, 10,12 years postoperatively. Results: Ninety six patients were implanted at either 1, 2 or 3 levels. Mean NDI improved from 65.2 to 22.1 (p .0001) at 8 years (mean follow up). Significant improvement was also observed through 8 years follow-up in neck and arm pain VAS (p .0001) and in physical (p .005) and mental component scores of the SF-12 (p .007). There were no serious adverse events related to the device. Radiographically, range of motion increased slightly and were maintained throughout the follow-up period (4-12 years). Conclusion: The C- ESP cervical artificial disc represents a new generation of cTDR design. Results of this study found the C-ESP device to produce excellent clinical and radiographic outcomes. Lucas Zubillaga 1 , Gareth Rutter 1 , Milly Huang 1 , Mitchell Hansen 1 1 John Hunter Hospital, Newcastle, Australia Introduction: In recent years total anterior cervical disc arthroplasty (ACDA) has become an effective alternative to Anterior Cervical Discectomy and Fusion (ACDF). Spinal fusion is postulated to accelerate degeneration of adjacent spinal segments caused by an alteration to the natural biomechanics of the spine. On the other hand, emerging long-term data suggest ACDA may be associated with complications such as osteolysis, heterotopic ossification and subsequently implant failure, potentially requiring additional surgery. This study aims to assess the prevalence of complications and medium to long-term clinical outcomes. Materials and Methods: We retrospectively reviewed all patients undergoing ACDA (single, multi-level, or hybrid procedures) under a single surgeon using an unconstrained non-articulating disc. Presence of myelopathy was assessed. Clinical and radiological outcomes were evaluated pre-treatment and at predetermined timepoints using quality of life (QoL) assessments (EuroQol), pain assessments (VAS), and disability scores (NDI, Oswestry, Roland Morris). Complications, including infection and implant removal or revision, were recorded. Additional surgery at the index or adjacent level was also recorded. Results: 79 patients underwent ACDA surgery between 2014 and 2023. 73% had single-level ACDA (n = 58), 25% had two-level surgery (n = 20, 19 hybrid, 1 non-hybrid), and 3% had 3-level hybrid procedures. Nine patients were treated for myelopathic signs. Follow-up ranged from 0 to 88 months (total 917 months). 41 patients had a follow up longer than 48 months. Two patients experienced infection which required hardware removal and fusion surgery. 39 patients who were reassessed at 5 years showed 12% decrease in EuroQoL, 28% improvement in NDI, 20% improvement in Oswestry, and 80% and 88% improvement in neck and arm VAS scores, respectively. Conclusions: Our series demonstrated promising medium-term outcomes with lower complication rates compared to previously published evidence. However, longer-term follow-up is needed to assess the incidence of clinically relevant osteolysis, heterotopic ossification and hardware failure. Further research is required to determine whether late osteolysis is due to chronic low infection or mechanical degeneration in order to prevent this rare complication. Kunfeng Song 1 1 Third People's Hospital of Henan Province, Minimally Invasive Spine Surgery Center, ZhengZhou, China Introduction: To compare the clinical efficacy of mini open (air/water medium) endoscopy assisted anterior cervical discectomy and fusion (MOEA-ACDF) and anterior cervical decompression and fusion (ACDF) in the treatment of cervical disc herniation (CSM). Material and Methods: A total of 120 cases of cervical disc herniation treated in our hospital from January 2018 to December 2022 were selected. The subjects were divided into MOEA-ACDF and ACDF groups. The operation time, intra-operative blood loss, and hospital stay of the two groups were recorded and compared, and the clinical symptoms were recorded at one week, one year, and two years after the operation. The neck and upper limb visual analog scale (VAS) score, Japanese Orthopedic Association (JOA) score, cervical range of motion (ROM), post-operative cervical lordosis angle and adjacent vertebral body height were compared between the two groups. Results: All 120 patients underwent successful operations. The intra-operative blood loss and operation time in the MOEA-ACDF group were significantly less than those in the ACDF group (p 0.05). One year after the operation, the cervical lordosis angle increased significantly in both groups (p < 0.05). However, ROM decreased significantly in the ACDF group (p 0.05). In the ACDF group, the height of the adjacent vertebral body increased 1 year after the operation (p 0.05). There was a significant difference in the height of the adjacent vertebral body between the two groups at the last follow-up (p 0.05). Conclusion: MOEA-ACDF is a minimally invasive treatment that is safe and effective. The medium- and short-term effects of MOEA-ACDF and ACDF in the treatment of cervical disc herniation are similar. Moreover, MOEA-ACDF combines the endoscopic system with ACDF technology in the treatment of CSM can achieve satisfactory clinical efficacy with high safety, and effectively restore the cervical intervertebral height and physiological curvature. Luke Pearson 1 , Seung Lee 2 , Jared Weeks 1 , Abdullah Alanazi 1 , Emilio Supsupin 1 , Daryoush Tavanaiepour 1 , Kourosh Tavanaiepour 1 , Dunbar Alcindor 1 , Vashisht Sekar 1 , Aboubakr Amer 1 1 University of Florida Jacksonville, Jacksonville, United States , 2 Mayo Clinic Jacksonville, Jacksonville, United States Introduction: Dysphagia can be caused by various factors, including anatomical abnormalities in the cervical spine. Cervical spondylosis, characterized by osteophytes in the cervical spine, can compress the esophagus, leading to swallowing difficulties. While surgical intervention, such as osteophytectomy, is typically performed to address neck pain and stiffness associated with cervical spondylosis, it can also be employed to treat dysphagia caused by esophageal compression. This case report presents a 72-year-old male who underwent C2/3 osteophytectomy with the aid of neuronavigation for dysphagia, highlighting the potential benefits of this approach. Material and Methods: The patient, a 72-year-old male, presented with progressive dysphagia for six months, primarily for solid foods. He experienced food sticking in his throat, a sensation of fullness, and occasional coughing during meals. A detailed medical history and physical examination were conducted, revealing a history of neck pain and stiffness. Radiological investigations included cervical spine X-rays and CT scan, which demonstrated bony spurs at the C4/5 level, consistent with cervical spondylosis. A barium swallow revealed a narrowing of the cervical esophagus at the level of C2/3, suggesting esophageal compression. Endoscopic evaluation confirmed the presence of esophageal narrowing without any evidence of inflammation or malignancy. Based on these findings, the patient underwent a C2/3 osteophytectomy to address the dysphagia caused by esophageal compression. Neuronavigation was utilized to ensure precise localization of the osteophytes and minimize muscle dissection. Results: Following the osteophytectomy, the patient experienced significant improvement in his swallowing function. The dysphagia gradually resolved, and he was able to resume a near-normal diet with minimal discomfort. Post-operative cervical spine X-rays and CT scan confirmed the successful removal of the osteophytes. No neurological complications were observed. Conclusion: This case report demonstrates the efficacy of neuronavigation-guided osteophytectomy in the treatment of dysphagia caused by esophageal compression due to cervical spondylosis. Neuronavigation provides precise anatomical guidance, minimizing the risk of complications and maximizing the potential for successful outcomes. While further research is needed to evaluate the long-term effectiveness and safety of this surgical approach for dysphagia management, this case suggests that neuronavigation-guided osteophytectomy can be a valuable tool for addressing swallowing difficulties associated with cervical spondylosis. Careful patient selection and a thorough understanding of the potential benefits and risks of the procedure are crucial for optimizing outcomes. Hania Shahzad 1 , Dagoberto Pina 1 , Zachary Booze 1 , Michael Seidu 1 , Joseph Wick 1 , Thomas Shen 1 , Yashar Javidan 1 , Rolando Roberto 1 , Eric Klinerberg 1 , Hai Le 1 1 UC Davis Health, Orthopedics, Sacramento, United States Introduction: Opioid over-prescription following surgical procedures, including anterior cervical spine (ACS) surgery, has contributed to a growing opioid crisis, with substantial health and economic burdens. Opioid prescriptions after ACS surgery show significant variability, leading to unnecessary use and an increased risk of opioid dependence. Efforts to standardize opioid prescribing practices have shown success in reducing opioid use without affecting postoperative pain management. This study investigates the impact of implementing a standardized opioid prescription protocol for patients undergoing ACS surgery in reducing opioid overuse without compromising pain control. Material and Methods: A prospective cohort study was conducted with a retrospective control group at a single academic institution. After Institutional Review Board (IRB) approval, we implemented a standardized opioid prescribing protocol for patients undergoing ACS surgery. The protocol limited the daily opioid dose to a maximum of 50 Morphine Milligram Equivalents (MME) for 2 weeks, with one optional refill. The study included 83 post-protocol patients and 315 pre-protocol patients, all of whom underwent elective anterior cervical discectomy and fusion (ACDF) or disc replacement (ACDR) surgeries. Patients’ age, surgery type, length of stay (LOS), opioid type, dailyMME, total MME, and refill requirements were collected from electronic medical records. Comparisons between the groups were performed using independent t-tests and chisquare tests. A multivariate regression analysis was performed to control for confounders such as prescriber level and surgical complexity. Results: The study included 83 patients in the post-protocol cohort and 315 patients in the pre-protocol cohort. There was no significant difference in age between the two groups, with an average age of approximately 55.4 years in the post-protocol group and 57.1 years in the pre-protocol group (p = 0.25). The length of stay (LOS) was similar between cohorts, with an average of 2.3 days. Most patients were discharged to home, with no significant difference in discharge disposition between the groups. The post-protocol cohort showed a significant reduction in both daily and total MME prescribed at discharge (p < 0.01). The pre-protocol group received a mean daily MME of 117.4 ± 63.6 compared to 42 ± 20 in the postprotocol group. The total MME prescribed was also significantly reduced (715.7 ± 522.2 vs. 330 ± 239.6, p < 0.01). No significant difference was observed in the need for refills between the cohorts (p = 0.35). Additionally, at 12 weeks post-surgery, fewer patients in the post-protocol group remained on opioids compared to the pre-protocol group (10% vs 20.71%, p = 0.03). Multivariate analysis confirmed that the implementation of the protocol significantly influenced the reduction in daily and total MME without impacting refill rates or prolonged opioid use. Conclusion: The introduction of a standardized opioid prescribing protocol post-ACS surgery effectively reduced the quantity of opioids prescribed without increasing the need for refills.Moreover, fewer patients in the post-protocol cohort were still using opioids at the 12-week follow-up. These findings demonstrate the efficacy of procedure-specific opioid prescription guidelines in reducing opioid over-prescription and associated long-term risks, contributing to better postoperative pain management and a reduction in the potential for opioid dependence.

Kazumichi Yagura 1 , Shu Takahashi 1 , Kazuyuki Segami 1 , Yusuke Oshita 2 , Koji Kanzaki 1 , Tomoaki Toyone 3 , Yoshifumi Kudo 3 1 Showa University Fujigaoka Hospital, Orthopaedic Surgery, Yokohama-city, Kanagawa, Japan , 2 Showa University Northern Yokohama Hospital, Orthopaedic Surgery, Yokohama-city, Kanagawa, Japan , 3 Showa University School of Medicine, Orthopaedic Surgery, Shinagawa-ku, Tokyo, Japan Introduction: The S1 pedicle screw (PS), iliac screw (IS), or S2-alar-iliac (S2AI) screw is commonly used as a pelvic anchor in adult spinal deformity (ASD) surgery. However, adjacent segment disease is an unavoidable complication of long spinal fusion. Recent studies have suggested that sacroiliac joint fixation may contribute to the progression of hip osteoarthritis (OA). At our institution, the Jackson technique (intrasacral fixation) was previously used as a pelvic anchor in ASD surgery. We hypothesized that this technique could mitigate the postoperative progression of hip OA owing to the preservation of sacroiliac joint movement compared to cases using IS or S2AI screws. We aimed to radiographically evaluate the progression of hip OA in patients who underwent ASD surgery combined with The Jackson technique. Material and Methods: This retrospective cohort study included 16 patients (32 hip joints) who underwent ASD surgery using the Jackson technique from 2017 to 2022. The joint space width (JSW) in the central space of the hip, center edge (CE) angle, and sharp angle were measured. The radiographic progression of hip OA was defined as a reduction of more than 0.5 mm/year in JSW. Results: The mean patient age was 67.3 years, with a mean follow-up period of 50.6 months. The mean number of fixation segments was 9.1. The respective preoperative and final follow-up visit measurements, which were not significantly different, were as follows: JSW, 4.5 mm and 4.2 mm; CE angle, 29.4° and 31.0°; and sharp angle, 41.5° and 39.8°. The rate of joint-space narrowing was 0.074 ± 0.18 mm/year. Hip OA progression was observed in one case (2.9%) during the observation period, necessitating total hip arthroplasty. Conclusion: In a previous study, the rate of joint space narrowing in cases where an IS or S2AI screw fixation was used for long spinal fusion was 0.31 mm/year. Another study suggested that 58% of patients with ASD who underwent sacroiliac joint fixation experienced hip OA progression one year after surgery. Our results demonstrated a lower progression rate of hip OA compared to previous reports, indicating that sacroiliac joint movement preservation could prevent hip OA progression. However, some patients required the replacement of Jackson rods with IS or S2AI screws because of distal junctional failure. The Jackson technique should be selected after considering the bone quality and extent of fixation. Adnene Benammou 1,2 , Souha Bennour 1,2 , Seddik Akremi 1,2 , Amal Abayed 1,2 , Mehdi Bellil 1,2 , Mohamed Ben Salah 1,2 1 University Tunis el Manar, Faculty of Medecine of Tunis, Tunis, Tunisia , 2 Charles Nicolle Hospital, Orthopedic Surgery Department, Tunis, Tunisia Introduction: Thoracolumbar fractures of the spine are common, and their management is well-documented according to different classification systems. However, the occurrence of these fractures in the onset of degenerative scoliosis has not been reported in literature. Material and Methods: This is a case report of a 73-year-old active male who sustained a work injury following a fall from a tree with an estimated height of 2 meters. Results: The patient presented initially at a local hospital with multilevel trauma with a hemopneumothorax needing a chest tube and a spinal injury. After a 12-day intensive-care-unit stay, the patient was transferred to our department. Initial examination found a bilateral motor deficit classified as ASIA C. Imaging found a type C fracture of the L1L2 Vertebras according to the AO Classification on a pre-existing degenerative spinal deformity with multilevel degenerative disk disease and foraminal stenosis. Because he was a high-risk patient and reported no previous complaint related to degenerative disk disease, we opted to treat the traumatic lesion alone. The patient benefited from a laminectomy with long segment fixation. At last, follow up the patient presented with a clean wound and partial neurological recovery . He was able to ambulate with aid. Conclusion: Degenerative scoliosis poses a therapeutic challenge especially in older patients where management opposes conservative treatment with focal surgery alone to taking the “opportunity” of the fracture to correct the deformity with multilevel fusion. There were no reported cases of type C fractures occurring on degenerative deformity spine although there were reports of fractures on intreated idiopathic scoliosis where the authors suggested that the goal was to establish the anatomy previous to the fracture. In our case, we opted to treat the fracture alone thus to reestablish the previous anatomy. Management of such fractures must take in consideration the patient complaints and the comorbidities that may make an extensive surgery not tolerated. Yangpu Zhang 1 , Honghao Yang 1 , Yong Hai 1 1 Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China Introduction: The surgical treatment of severe and complex adult spinal deformity (ASD) commonly required three-column osteotomy (3-CO), which was technically demanding with high risk of neurological deficit. Personalized three dimensional (3D)-printed guide template based on preoperative planning has been gradually applied in 3-CO procedure. The purpose of this study was to compare the efficacy, safety, and precision of 3D-printed osteotomy guide template and free-hand technique in the treatment of severe and complex ASD patients requiring 3-CO. Material and Methods: This was a single-centre retrospective comparative cohort study of patients with severe and complex ASD (Cobb angle of scoliosis > 80° with flexibility 90°) who underwent posterior spinal fusion and 3-CO between January 2020 to January 2023, with a minimum 12 months follow-up. Personalized computer-assisted three-dimensional osteotomy simulation was performed for all recruited patients, who were further divided into template and non-template groups based on the application of 3D-printed osteotomy guide template according to the surgical planning. Patients in the two groups were age- and gender- propensity-matched. The radiographic parameters, postoperative neurological deficit, and precision of osteotomy execution were compared between groups. Results: A total of 40 patients (age 36.53 ± 11.98 years) were retrospectively recruited, with 20 patients in each group. The preoperative focal kyphosis (FK) was 92.72° ± 36.77° in the template group and 93.47° ± 33.91° in the non-template group, with a main curve Cobb angle of 63.35° (15.00°, 92.25°) and 64.00° (20.25°, 99.20°), respectively. Following the correction surgery, there were no significant differences in postoperative FK, postoperative main curve Cobb angle, correction rate of FK (54.20% vs. 51.94%, p = 0.738), and correction rate of main curve Cobb angle (72.41% vs. 61.33%, p = 0.101) between the groups. However, the match ratio of execution to simulation osteotomy angle was significantly greater in the template group than the non-template group (coronal: 89.90% vs. 74.50%, p < 0.001; sagittal: 90.45% vs. 80.35%, p < 0.001). The operating time (ORT) was significantly shorter (359.25 ± 57.79 min vs. 398.90 ± 59.48 min, p = 0.039) and the incidence of postoperative neurological deficit (5.0% vs. 35.0%, p = 0.018) was significantly lower in the template group than the non-template group. Conclusion: Performing 3-CO with the assistance of personalized 3D-printed guide template could increase the precision of execution, decrease the risk of postoperative neurological deficit, and shorten the ORT in the correction surgery for severe and complex ASD. The personalized osteotomy guide had the advantages of 3D insight of the case-specific anatomy, identification of osteotomy location, and translation of the surgical planning or simulation to the real surgical site. Junyu Li 1 , Zekun Li 1 , Yilin Lu 1 , Xiang Zhang 1 , Zhuo Ran Sun 1 , Yongqiang Wang 1 , Weishi Li 1 , Miao Yu 1 1 Peking University Third Hospital of China, Beijing, China Introduction: Surgical correction is a common treatment for severe scoliosis. Due to the significant spinal deformation that occurs with this condition, spinal cord injuries during corrective surgery can occur, sometimes leading to paralysis. Here, we created three-dimensional FE models specifically matched to the spinal cords of study patients in order to examine spinal cord stress distribution during scoliosis correction surgery. These findings may help clinicians better predict the spinal segments where neurological complications could occur during surgery. Material and Methods: Such events are associated with biomechanical changes in the spinal cord during surgery, however, their underlying mechanisms are not well understood. Six patient-specific cases of scoliosis either with or without spinal complications were examined. Finite element analyses (FEA) were performed to assess the dynamic changes and stress distribution of spinal cords after surgical correction. The FEA method is a numerical technique that simplifies problem solving by replacing complex problem solving with simplified numerical computations. Results: In four patients with poor prognosis, there was a concentration of stress in the spinal cord. The predicted spinal cord injury areas in this study were consistent with the clinical manifestations of the patients. In two patients with good prognosis, the stress distribution in the spinal cord models was uniform, and they showed no abnormal clinical manifestations postoperatively. Conclusion: This study identified a potential biomechanical mechanism of spinal cord injury caused by surgical correction of scoliosis. Numerical prediction of postoperative spinal cord stress distribution might improve surgical planning and avoid complications. Junyu Li 1 , Jiahao Zhang 1 , Siming Xian 1 , Wenbin Bai 1 , Yihao Liu 1 , Zhuo Ran Sun 1 , Yongqiang Wang 1 , Miao Yu 1 , Weishi Li 1 , Yan Zeng 1 1 Peking University Third Hospital, Beijing, China Introduction: Osteoporotic vertebral compression fractures (OVCF) caused by osteoporosis is a common clinical fracture type. There are many surgical treatment options for OVCF, but there is a lack of comparison among different options. Therefore, we counted a total of 104 cases of OVCF operations with different surgical plans, followed up the patients, and compared the surgical outcome indications before, after and during the follow-up. Material and Methods: 104 patients who underwent posterior osteotomy (Modified PSO, SPO, PSO, VCR) and kyphosis correction surgery at our hospital between April 2006 and August 2021 with a minimum follow-up period of 24 months were included. All cases were injuries induced by a fall incurred while standing or lifting heavy objects without high-energy trauma. The mean CT value was 71 HU, which was below 110 HU, indicating severe osteoporosis. The indications for surgery included gait disturbance due to severe pain with pseudarthrosis, increased kyphotic angle, and progressive neurological symptoms. Pre- and postoperative CL, TLK, TK, PrTK, TKmax, GK, LL, PI, SS, PT, SVA, TPA, were investigated radiologically. Additionally, We evaluated estimated blood loss, surgical time and perioperative symptom. Results: The results show, after operation, TLK (37.32  ±  10.61° vs. 11.01  ±  8.06°, p  <  0.001), TK (35.42  ±  17.64° vs. 25.62  ±  12.24°, p  < 0.001), TKmax (49.71  ±  16.32° vs. 24.12  ±  13.34°, p  <  0.001), SVA (44.91  ±  48.67 vs. 23.52  ±  30.21, p  =  0.013), CL (20.23  ±  13.21° vs. 11.45  ±  9.85°, p  =  0.024) and TPA (27.44  ±  12.76° vs. 13.91  ±  9.24°, p  =  0.009) were improved significantly in modified Pedicle subtraction osteotomy (mPSO) after operation. During follow-up, TLK (37.32 ± 10.61° vs. 13.88 ± 10.02°, p < 0.001) and TKmax (49.71 ± 16.32° vs. 24.12 ± 13.34°, p < 0.001) were improved significantly in Modified PSO group. In addition, estimated blood loss (790.0 ± 552.2 ml vs. 987.0 ± 638.5 ml, p = 0.038), time of operation (244.1 ± 63.0 min vs. 292.4 ± 87.6 min, p = 0.025) were favorable in Modified PSO group compared to control group. Conclusion: To conclude, mPSO could acquire a favorable degree of kyphosis correction as well as early and high bone union. Compared with other surgical methods, it also has the advantages of less surgical trauma and shorter operation time. It can be an effective solution for the treatment of OVCF. Yong Hai 1,2 , Zihao Ding 1 , Yunsheng Wang 1,2 , Lijin Zhou 1,2 1 Beijing Chaoyang Hospital, Capital Medical University, Orthopedic Surgery, Beijing, China , 2 Center for Spinal Deformity, Capital Medical University, Beijing, China Introduction: Ankylosing spondylitis (AS) is an inflammatory seronegative arthropathy affecting mainly the medial skeleton. AS causes joint pain, stiffness, and severe thoracolumbar kyphosis deformity (TKD), further restricting the patient’s daily mobility. This phenomenon frequently occurs in individuals who have reached severe stages of AS. The intensity of thoracolumbar kyphosis may diminish ambulatory capacity and compromise the ability to maintain an upright and comfortable posture. TKD exerts a discernible effect on both an individual’s physical look and functional abilities, possibly causing severe problems such as respiratory distress. The use of trans-intervertebral osteotomy as a stand-alone procedure is limited to cases of mild-to-moderate kyphotic deformities, in which the primary manifestation is compression of the anterior column. Patients with partial compression of the middle and posterior columns may not achieve satisfactory corrective outcomes using this approach. Furthermore, surgeons currently have difficulty with the increased occurrence of neurological problems resulting from direct or indirect intraoperative spinal cord injury. This study aimed to assess the efficacy of a novel spinal osteotomy technique, the posterior trans-intervertebral osteotomy with anterior support, in individuals diagnosed with ankylosing spondylitis. This study utilized computer software to simulate the osteotomy procedure, predict orthopedic outcomes, and assist in preoperative planning. Material and Methods: Patients with ankylosing spondylitis underwent posterior trans-intervertebral osteotomy with anterior support. Osteotomy was performed using the intervertebral space approach with the cage placed anteriorly in the intervertebral space to improve the correction. Perioperative clinical symptoms, imaging data, and surgical factors were also documented. Results: Patients who underwent posterior trans-intervertebral osteotomy with anterior support achieved good clinical results with favorable correction rates and minimal estimated blood loss. The average preoperative and postoperative Cobb angles were 90.5° (range: 86-96°) and 43.5° (range: 34-52°), respectively. The average estimated blood loss was 500 mL (range: 300-800 mL). Patients with preoperative deficits improved their neurological status, and no complications were observed throughout the postoperative period. Conclusion: Posterior trans-intervertebral osteotomy with an anterior support procedure was performed through the intervertebral space and subsequent implantation of a cage within the transpedicular space, effectively addressing the constraints associated with the conventional trans-intervertebral osteotomy method. Our preliminary findings indicate that posterior trans-intervertebral osteotomy with anterior support is potentially more secure than the conventional method for correcting ankylosing spondylitis kyphosis. Christopher Mikhail 1 , Fthimnir Hassan 2 , Stephen Stephan 3 , Andrew Platt 4 , Erik Lewerenz 2 , Joseph Lombardi 2 , Zeeshan Sardar 2 , Ronald A. Lehman 2 , Lawrence Lenke 2 1 Cedar Sinai Medical Center, Los Angeles, United States , 2 Columbia University Irving Medical Center, New York, United States , 3 Scripps Health, La Jolla, United States , 4 Loma Linda University Health, Loma Linda, United States Introduction: Adult Spinal Deformity (ASD) is a broad category of pathology that has more recently seen increased research interest. Although numerous studies describe outcomes of surgical correction of adult spinal deformity, few studies have looked the outcomes of surgical correction of the distinct population of Adult Idiopathic Scoliosis (AdIS). The purpose of this study is to demonstrate whether AdIS patients fused to the sacrum will have inferior outcomes and more complications to those fused above the sacrum. Methods: This was a retrospective study of AdIS patients who underwent surgery with minimum 2yr follow up. Patient demographics, perioperative data, radiographic parameters and patient reported outcomes (PROs) were collected at baseline and final follow up. Curve types were based on the senior author’s proposed AdIS classification. Patients were dichotomized based on whether they were fused to the sacrum (SAC) or with a lower instrumented vertebrae (LIV) above the sacrum (NonSAC). Outcome measures included difference in PROs, complications, and overall outcomes at final follow up. Results: 72 patients (N = 34 SAC, N = 38 NonSAC) were included. Curve types differed significantly between the 2 groups with all type 1 and 2 curves belonging to NonSAC, and nearly all type 3, 4, 6 curves belonging to SAC patients (p < 0.0001). SAC patients were older (55.8 ± 8.7 vs 31.1 ± 11.6, p < 0.0001), had greater EBL (1675.8 ± 683.0cc vs 914.5 ± 582.0cc, p < 0.0001), longer OR times (8.5 ± 1.1 hr vs 5.7 ± 1.9 hr, p < 0.0001) and longer LOS (7.0 ± 2.3d vs 4.1 ± 1.4d, p < 0.0001). SAC patients had larger thoracolumbar/lumbar (65.2 ± 12.3 vs 41.4 ± 15.6, p < 0.0001), lumbosacral curves (27.7 ± 9.2 vs 15.9 ± 11.3, p < 0.0001), and were more malaligned in the sagittal plane at baseline (SVA: 26.8 ± 40.3mm vs -16.8 ± 29.0, p < 0.0001). NonSAC patients, however, had a larger proximal thoracic curve (28.5 ± 14.9 vs 20.9 ± 12.8, p = 0.0337), lumbar lordosis (63.3 ± 13.5 vs 43.6 ± 16.8, p < 0.0001), and T2-T5 thoracic kyphosis (20.2 ± 11.8 vs 13.0 ± 8.3, p = 0.0044) at baseline. Both groups saw significant improvements in both radiographic parameters and in PROs at final follow up. At baseline, NonSAC presented with greater SRS22r function (4.1 ± 0.8 vs 3.7 ± 0.8, p = 0.0480), pain (3.5 ± 0.9 vs 3.0 ± 0.8, p = 0.0148), and ODI score (19.4 ± 16.9 vs 27.3 ± 14.8, p = 0.0430), NonSAC patients demonstrated a greater function score (4.6 ± 0.4 vs 4.1 ± 0.7, p = 0.0055) and lower ODI score (7.3 ± 7.6 vs 14.4 ± 13.3, p = 0.0121) at the final follow up. Despite these differences, there was no significant difference in SRS-22r total score at final follow up (SAC: 4.1 ± 0.6 vs NonSAC: 4.3 ± 0.4, p = 0.1159). No differences in intraoperative (p = 0.999) complications were observed. However, SAC patients were more likely to experience postop ileus while admitted (29.4% vs 7.9%, p = 0.0178). Although SAC patients reported greater complications between 1yr and final follow up (p = 0.0048), no difference were observed among revision rates and stratified complications (p > 0.05). Conclusions: AdIS patients treated to the SAC and NonSAC both improved radiographically and clinically with surprisingly similar SRS-22r total scores at final follow up, but NonSAC patients reporting greater function and less disability. Although SAC patients did experience more complications after 1yr, no difference in revision rates was seen. Fthimnir Hassan 1 , Lawrence Lenke 1 , Erik Lewerenz 1 , Peter Passias 2 , Eric Klineberg 3 , Virginie Lafage 4 , Shay Bess 5 , Justin Smith 6 , D. Kojo Hamilton 7 , Jeffrey Gum 8 , Renaud Lafage 4 , Jeffrey Mullin 9 , Michael Kelly 10 , Bassel Diebo 11 , Thomas Buell 12 , Justin Scheer 13 , Breton Line 5 , Han Jo Kim 14 , Khaled Kebaish 15 , Robert Eastlack 16 , Alan Daniels 11 , Alex Soroceanu 17 , Gregory Mundis 16 , Richard Hostin 18 , Themistocles Protopsaltis 2 , Munish Gupta 19 , Frank Schwab 4 , Christopher Shaffrey 20 , Christopher Ames 21 , Douglas Burton 22 1 Columbia University Irving Medical Center, New York, United States , 2 New York University, Langone Medical Center, New York, United States , 3 UTHealth McGovern Medical School, Houston, United States , 4 Lenox Hill Hospital, New York, United States , 5 Denver International Spine Center, Denver, United States , 6 University of Virginia Health System, Charlottesville, United States , 7 University of Pittsburgh Medical Center, Pittsburgh, United States , 8 Leatherman Spine Center, Louisville, United States , 9 University of Buffalo, Buffalo, United States , 10 Rady Children's Hospital, San Diego, United States , 11 Warren Alpert School of Medicine, Brown University, Providence, United States , 12 University of Pittsburgh Medical Center, New York, United States , 13 Cedar Sinai Medical Center, Los Angeles, United States , 14 Hospital for Special Surgery, New York, United States , 15 Johns Hopkins University School of Medicine, Baltimore, United States , 16 Scripps Health, La Jolla, United States , 17 University of Calgary, Calgary, Canada , 18 Southwest Scoliosis Institute, Plano, United States , 19 Washington University in St Louis, St Louis, United States , 20 Duke University Medical Center, Durham, United States , 21 University of San Francisco, San Francisco, United States , 22 University of Kansas Medical Center, Kansas City, United States Introduction: Lumbar decompressions are traditionally done to alleviate compressed nerves among adult spinal deformity (ASD) patients with lower extremity (LE) weakness. However, patients may still manifest LE weakness early postop despite extensive lumbar decompressions. The purpose of this study is to determine whether lumbar decompressions alone will improve lower extremity motor scores (LEMS) among ASD patients with preoperative motor impairment. Methods: This study is an analysis of a prospective, multicenter cohort of ASD patients with ≥ 1 procedural and/or radiographic criteria: PI-LL ≥ 25°, TPA ≥ 30°, SVA ≥ 15 cm, thoracic scoliosis ≥ 70°, thoracolumbar scoliosis ≥ 50°, global coronal malalignment ≥ 7 cm, ≥ 12 instrumented levels, and/or undergoing 3-column osteotomy (3CO). Patients with baseline abnormal LEMS, defined as a combined score < 50 (25 per lower extremity) at baseline, were dichotomized based on whether their LEMS improved from baseline (IBL) or deteriorated further (DBL) by the first/6-week postop visit (6W). Patients who maintained their LEMS by 6W compared to baseline were excluded. Patient and operative characteristics were compared through bivariate analyses to assess differences in treatment. Following bivariate analyses, a multivariable logistic regression model was built to discern independent factors associated with improved LEMS while controlling for potential confounders. Results: 121 patients were included where 90.1% (N = 109) improved by 6W while 9.9% (N = 12) experienced further deterioration. Both groups had similar BL LEMS when stratified by both laterality and per nerve root. The groups were identical in age, gender, comorbidities, baseline LEMS, body mass index (BMI), number of revision cases, instrumented levels, estimated blood loss (EBL), operative (OR) time, and length of stay (LOS) (p > 0.05). No differences in radiographic parameters at baseline and 6W were observed aside from DBL experiencing greater change in the L1 pelvic angle (∆L1PA) (-8.0 ± 8.3 vs -1.6 ± 7.6, p = 0.0413). Despite having similar frequencies of lumbar decompressions performed across a similar number of levels, DBL had less lumbar posterior column osteotomies (PCOs) performed (50% vs 82.6%, p = 0.0169). No differences in 3COs performed were observed. Nevertheless, DBL experienced greater intraoperative neuromonitoring (IONM changes) (41.7% vs 8.3%, p = 0.0050), all of which were motor deficits. Despite 60% of these cases recovering before discharge, DBL as a whole experienced greater LEMS deterioration across all neve roots irrespective of laterality (p < 0.05). Controlling for ∆L1PA discerned lumbar PCOs as an independent driver of improved LEMS [OR = 6.75 (1.63 – 27.84)] with great model statistics (p < 0.0001, AUC = 0.80, Hosmer & Lemeshow Goodness-of-Fit Test p = 0.4178). Conclusions: Lumbar decompressions alone may not be enough to improve LE weakness among ASD patients with preoperative motor impairment while the use of PCO’s was beneficial for improvement. Thus, more aggressive and thorough Asham Khan 1 , Esteban Quiceno Restrepo 1 , Isabelle Stockman 2 , Shashwat Shah 2 , Joseph St. Onge 2 , Alexander Aguirre 1 , Mohamed Soliman 1 , John Pollina 1 , Jeffrey Mullin 1 1 University at Buffalo Neurosurgery, Buffalo, United States , 2 Jacobs School of Medicine and Biomedical Sciences, Buffalo, United States Introduction: Surgical indications and management of Adult Idiopathic Scoliosis (AdIS) are not well defined. There is little utility in adolescent thresholds for surgical intervention in the adult population. Surgical management has become more frequent but is associated with high rates of complications. Materials and Methods: A systematic MEDLINE/PubMed database search was performed between January 1, 2000, to December 30, 2019, based on PRISMA guidelines. Studies were screened and selected based on predefined inclusion and exclusion criteria. Only patients who underwent surgical intervention were included. Study characteristics, patient description, longitudinal radiographic, and patient outcomes assessment data were extracted. The quality of the study was assessed utilizing the NIH study quality assessment tool. Meta-analysis was conducted to assess radiographic change with surgical intervention. Univariate meta-regression analysis was conducted to identify predictors of the effects. Subgroup analysis dichotomized by age was conducted on coronal and sagittal changes. Results: Patients who undergo surgery were in their second or fourth decade of life. The mean preoperative MC (57.8º) had an average correction of 58.1 ± 15.9% and was maintained through follow-up. The mean preoperative thoracic kyphosis (remained within the normal limits through follow-up. The mean LL (45.9º), PT (17.2 º), and SVA (15.1 ± 16.8 mm) were all within normal limits. Meta-regression analysis revealed that ΔMC was influenced by SVA, ΔSVA was influenced by TK, and ΔTK was influenced by flexibility and preoperative MC. Conclusions: The overall correction of the coronal plane was maintained at follow-up with an intimate correlation with the sagittal plane. The behavior of TK had the least degree of variability among studies. Further studies are necessary to identify the source of this ΔTK. Esteban Quiceno Restrepo 1 , Mohamed Soliman 1 , Jacob Greisman 1 , Asham Khan 1 , John Pollina 1 , Jeffrey Mullin 1 1 University at Buffalo Neurosurgery, Neurosurgery, Buffalo, United States Introduction: Correcting sagittal malalignment in adult spinal deformity (ASD) poses significant challenges. Proposed three column osteotomies, including Schwab 3 osteotomy, the “Sandwich” technique, Schwab 4 osteotomy, and Schwab 4 plus interbody cage, are aimed at achieving alignment goals. The aim of this study is to compare outcomes of three-column osteotomies with and without the use of a cage. Material and Methods: Preoperative demographic characteristics, radiographic measurements, patient-reported outcomes, complications, and fusion rates were evaluated preoperatively and at a 2-year follow-up. Three blinded, surgeons based on serial radiographs determined fusion grading. Univariate and multivariate analyses were performed to assess fusion outcomes between groups. Comparisons were made between the four-osteotomy groups and the cage and none-cage groups. Results: Patients undergoing the “Sandwich osteotomy” exhibited worse preoperative leg pain scores and lower SRS activity (p = 0.015), appearance (p = 0.007), and mental health domain scores (p = 0.0015), yet this group showed the largest mean change in the SRS mental health domain (p = 0.005). No differences in complications were found between groups (p > 0.05). Patients who underwent osteotomy with a cage were more likely to have had previous spine fusion (91.7% vs 71.4%, p = 0.010). Additionally, these patients had lower preoperative SRS mental domain scores (2.9 ± 1 vs 3.59 ± 1, p = 0.009), satisfaction scores (2.39 ± 1 vs 2.79 ± 1.2, p = 0.034), and lower preoperative SRS total scores (2.39 ± 0.6 vs 2.69 ± 0.6, p = 0.0026), but demonstrated the largest improvement in the mental health domain (0.99 ± 0.7 vs 0.39 ± 0.9, p = 0.002). The use of a cage was associated with a larger mean change in segmental lordosis at the osteotomy site (32.99 ± 9.6 vs 28.79 ± 9.5, p = 0.038). Posterolateral fusion and circumferential fusion rates were significantly higher in the cage group (79.2% vs 55.1%, p = 0.0012). Regression analysis identified the use of a cage at the osteotomy as an independent predictor for posterior fusion (OR95%3.338,CI,1.108-10.054, p = 0.032). Conclusion: While incorporating an interbody cage at contiguous disc spaces or the osteotomy site did not correlate with increased complication rates, it did show a higher incidence of posterolateral and circumferential fusion at the two-year postoperative mark and better segmental lordosis at the osteotomy site. Sergio Díaz Bello 1 , Alberto Perez 2 , Diana Chávez 3 1 Hospitales Ángeles, Neurocirugía, Ciudad de México, Mexico , 2 Hospitales Angeles, Neurocirugía, Ciudad de México, Mexico , 3 Hospitales Angeles, Neurocirugía, Ciudad de Méxicon, Mexico Introduction: In spinal deformity surgery, a final step in the surgical management of these patients is manual contouring of the spinal rods, which is in most cases neither accurate nor reproducible. The main objective of this study is the contouring of the spinal rods adapted to the ideal and individual sagittal balance of each patient, as described by Roussouly et al. based on patient-specific preoperative and intraoperative radiographic templates as well as the analysis of clinical radiographic results. Material and Methods: Description of 3 clinical cases of adult spinal deformity. The first case is a 68-year-old female with adult spinal deformity in coronal and sagittal plane classified as Roussouly type 4 in whom correction of both deformities was performed with anterior fusion and posterior osteotomies plus T4-S2 Alar-Iliac screw instrumentation, the second case is a 65-year-old man classified as Roussouly type 1 with correction of coronal and sagittal deformity only by posterior approach T8-S2 Alar-Iliac screw and the third case is a 54-year-old man classified as Roussouly type 3 who presented only coronal deformity resolved with anterior and lateral approach as well as T2-S1 instrumentation. In all cases, the technique we propose for molding the spinal rods was applied. After implant placement and osteotomies, 2 spinal rods were molded by matching them with the preoperative radiographic study and the x-ray studies taken during surgery and adapted to the osteotomies and implants using x-rays to have in real time the number of lordotic vertebrae, apex of the curve of the bar and the objective thoracolumbar transition according to the type of classification described by Roussouly, allowing us to modify them during surgery in case these characteristics were not adequate by comparing them with the transoperative radiographic study. Results: Patients were evaluated for pain and function, showing improvement in the analog pain scale (VAS) and minimal disability in the Owestry and Roland-Morris scales. Regarding the postoperative radiological parameters, they showed restoration of the sagittal and coronal alignment to normal objective parameters with the 2 spinal rods symmetrically adapted, a pelvic incidence, sacral slope, pelvic tilt, lumbar lordosis, apex of the curve and thoracolumbar transition for the ideal type classified by Roussouly, which was directly related to the improvement in pain and function. Conclusion: The proposed method is innovative as it has not been described in the literature reviewed to date and provides an advantage over other techniques described as those based on software since having a preoperative and intraoperative image reference helps us to adapt it to the ideal type of spine already studied by Roussouly et al. It also allows modifications to be made in case of using intervertebral implants or osteotomies. Kunal Chanji 1 , Sajan Hegde 1 , Appaji Krishnan 1 , Vignesh Badikillaya 1 , Harith Reddy 1 , Sharan Achar Thala 1 , Akshya Raj 1 , Sakthivel Ramaswamy 1 1 Apollo Hospitals, Spine Surgery, Chennai, India Introduction: The maintenance of sagittal balance has direct impact on outcomes and quality of life in any spine intervention. No single characteristic in the literature on thoracolumbar surgery is as strongly correlated with successful surgical outcomes. An imbalance in the sagittal plane causes pain and energy expenditure when standing. In order to restore sagittal imbalance in adult spinal deformities, adequate lumbar lordosis (LL) must be created. Based on biomechanical research, the L3-S1 segment is responsible for around 85% of lumbar lordosis. A substantial amount of information is available regarding how common surgical techniques affect sagittal balance; however, no resource has thoroughly described the outcomes based on the available data. For the optimal correction of sagittal alignment, restoring a sagittal vertical axis (SVA) < 5 cm is suggested. According to canonical theory, ALIF provides the highest degrees of correction, followed by L-LIF and TLIF. This case report challenges the existing reasoning on the correction of lumbar lordosis and its association with the main interbody fusion procedures commonly employed for the lumbar spine. It invites reconsideration of current concepts and puts Unilateral Transforaminal lumbar interbody (UNI-TLIF) fusions using a modular banana cage and unilateral pedicle screw fixation as a potential option even in globally imbalance spine with careful patient selection. Material and Methods: A case report of a 45-year-old female patient with severe low back pain radiating to right lower extremity with numbness and tingling for 5 months. The pain was severe and the patient was unable to stand. Patient was unable to perform her activities of daily living. The patient had no history of constitutional symptoms and had no co-morbidities. The initial examination did not reveal neurological deficit although the patient showed signs of sagittal imbalance. Preoperative X-ray revealed multilevel degenerated discs at lumbar spine with lumbar kyphosis with global sagittal imbalance. Preoperative MRI examination showed that there was severe foraminal stenosis at L5S1. After due written informed consent, the patient underwent UNI-TLIF at L5S1. Results: The operative time was 45 mins, and the intraoperative blood loss was less than 50 ml. There was no postoperative drain kept. The patient was hospitalized for a total of 9 hours. The patient had immediate relief of the back pain and the radicular pain and was mobilized within 4 hours of the surgery. Immediate postoperative, patient’s sagittal profile improved. 3-month postoperative radiographs and clinical profile revealed restoration of lumbar lordosis with good sagittal balance. SVA improved from 20 mm to 2 mm and Lumbar kyphosis of 6 degree improved to lumbar lordosis of 24 degrees. Immediate postoperative and on 3 months follow up there was significant improvement in VAS, JOA, ODI scores. Conclusion: Treating big problems with big solutions isn’t always the best. A simple small day care procedure of UNI-TLIF relieved the symptoms of back pain and achieved good clinical and sagittal outcomes with the added advantage of minimal intra-operative time, minimal intra-operative bleeding and hastened post operative recovery. Devender Singh 1 , Matthew Geck 1 , Vik Kohli 1 , Qais Zai 1 , Eeric Truumees 1 , John Stokes 1 1 Ascension, Austin, United States Introduction: Scheuermann’s kyphosis is a spinal deformity that can significantly impair quality of life. Surgical correction aims to restore sagittal alignment and improve functional outcomes, but predicting postoperative improvements remains challenging. Radiographic factors such as pelvic incidence-lumbar lordosis mismatch (PI-LL mismatch) and thoracic kyphosis (TK) are often used to guide surgical decisions, but their direct influence on clinical outcomes like the Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) is not well understood. Understanding the interplay between clinical and radiographic factors could optimize surgical planning and patient care. This study aimed to investigate the clinical and radiographic predictors of postoperative improvement in ODI and VAS scores in patients undergoing spinal surgery for Scheuermann's Kyphosis. We hypothesized that greater reductions in radiographic misalignments, particularly PI-LL mismatch and TK, would be associated with significant improvements in postoperative ODI and VAS scores. Material and Methods: A retrospective analysis was conducted on a cohort of 40 patients who underwent surgical correction for Scheuermann’s kyphosis. Demographic data (age, BMI, operative time), radiographic measures (preoperative and postoperative PI-LL mismatch, TK, T1 pelvic angle [TPA], lumbar lordosis), and clinical outcomes (ODI, VAS) were collected. Statistical analysis included Spearman’s rank correlation, non-parametric tests (Mann-Whitney U), and Lasso regression to identify the strongest predictors of postoperative ODI and VAS improvement. Cross-validation was used to avoid overfitting. Results: The mean age of the patients was 19.7 years (SD: 5.88), with a mean BMI of 24.78 (SD: 6.23). The average operative time was 319.28 minutes (SD: 44.37). The number of spinal levels treated ranged from 10 to 14 (mean: 13). Preoperative ODI scores averaged 19.87, with postoperative ODI improving to 12.78. VAS scores showed similar improvements, decreasing from 30.0 preoperatively to 17.52 postoperatively. Lasso regression identified BMI (Coefficient = 5.39), reductions in PI-LL mismatch (Coefficient = 7.25), and TPA (Coefficient = 3.70) as the strongest predictors of ODI improvement. Reductions in lumbar lordosis (ΔLL) were negatively associated with ODI improvement (r = -0.60), indicating that overcorrection of lumbar lordosis might impede functional recovery. A significant difference in VAS improvement was found between shorter and longer surgeries (p = 0.037), with longer surgeries associated with greater pain relief. Preoperative pain severity (VAS) was a strong predictor of postoperative pain relief (r = 0.74), suggesting that patients with higher preoperative pain had more scope for improvement. Conclusion: The findings suggest that radiographic corrections, particularly in PI-LL mismatch and TPA, are key drivers of functional improvement in spinal surgery. Interestingly, higher BMI was associated with greater ODI improvement, which may reflect a greater scope for postoperative recovery in patients with higher preoperative disability. Overcorrection of lumbar lordosis may impair functional recovery, highlighting the need for precise surgical planning. While complications did not significantly affect functional outcomes, they were associated with poorer pain relief, emphasizing the importance of managing postoperative complications. Devender Singh 1 , Matthew Geck 1 , Qais Zai 1 , Vik Kohli 1 , Eeric Truumees 1 , John Stokes 1 1 Ascension, Austin, United States Introduction: Cervical lordosis (CL) plays a critical role in maintaining sagittal balance and spinal function. Changes in cervical alignment, particularly cervical kyphosis, have been associated with neck pain, disability, and neurological impairment. The T1 Pelvic Angle (TPA) is a key marker of sagittal alignment, and significant improvements in TPA are hypothesized to influence CL outcomes. However, the relationship between postoperative (postop) TPA changes and improvements in CL is not fully understood. Identifying the threshold for clinically meaningful TPA improvement and the role of other demographic factors, such as age and sex, could guide clinical decision-making. This study aims to investigate the change in cervical lordosis (CL) after significant TPA improvement (≥ 10°) and to assess the impact of demographic factors (age, sex), preop TPA, and CL on postop CL outcomes. We also aim to establish if a threshold TPA improvement leads to clinically significant CL changes. Our hypothesis was that a postop TPA improvement of 10° or more will demonstrate significant improvements in cervical lordosis, and that these changes will be influenced by factors such as age, sex, and preoperative (preop) spinal alignment. Material and Methods: This retrospective cohort study analyzed data from patients who underwent deformity spinal surgery with preop and postop measurements of TPA and CL. Statistical analyses included subgroup analysis by sex and age, linear regression to determine the relationship between TPA and CL change, and multivariate regression to explore prognostic factors. Results: The study included 167 patients, of which 65.3% were females and 34.7% were males. The average age of patients was 67 years, with an age range of 59 to 74 years. The preop CL was more negative in females (-24.6°) than in males (1.47°), suggesting greater preop cervical kyphosis in females. At 6 months postop, patients with a TPA improvement of 10° or more experienced a significant improvement in CL, with an average change of 7.17° (p-value = 0.004). In contrast, patients with less than 10° TPA improvement exhibited a worsening in CL by an average of -3.61°. Subgroup analysis revealed that sex and age had minor effects on CL improvement. Females showed a greater improvement (7.70°) compared to males (4.37°), though this difference was not statistically significant (p-value = 0.591). Age-wise, patients over 65 years exhibited a greater improvement in CL (8.86°) compared to younger age groups, though the age-related differences were also not statistically significant (p-value = 0.206). A linear regression model demonstrated a weak but statistically significant relationship between TPA improvement and CL change (R 2 = 0.094, p-value = 0.004). Conclusion: Patients with a TPA improvement of 10° or more demonstrated a significant improvement in cervical lordosis, confirming the importance of achieving optimal sagittal alignment. Moderate TPA improvement (5-10°) had the most significant effect on CL improvement, while larger improvements (> 15°) had a reduced impact. Age and sex had minor influences on CL improvement, but these factors were not statistically significant. These findings underscore the importance of TPA correction in clinical practice to improve postoperative cervical alignment. Stanley Kisinde 1 , Isador Lieberman 1 , Adam Archie 2 , Raymond Waldrop III 3 1 Texas Back Institute, Scoliosis & Spine Tumor Center, Frisco, United States , 2 The Medical College of Georgia at Augusta University, Department of Orthopaedic Surgery, Augusta, United States , 3 JPS Health Network, Department of Orthopaedic Surgery, Fortworth, United States Introduction: Cement-augmented pedicle screw instrumentation (CAPSI) procedures are performed for spinal stabilization in patients with surgical conditions of the spine with poor bone quality at the target levels, whose symptoms are refractory to conservative measures. Although this is done to combat the risk of failure due to loosening, cutting out or pulling out of the screws, failure may still occur. The purpose of this study was to identify the modalities and rates of failure of CAPSI constructs to better predict occurrence of failure. Material and Methods: We retrospectively reviewed the clinical charts and radiological imaging for patients who underwent CAPSI spinal fusion procedures between 2010-2022, all performed by a single surgeon. We collected pre, intra and post-operative clinical and radiographic data, evidence of construct failure, associated factors, and revision surgical procedures, where applicable. Results: In total, 621 pedicle screws in 319 levels were augmented out of 1333 screws in 809 instrumented levels in 120 patients. F:M ratio was 3:1, mean age 68.6 years and mean BMI was 27.10. The most common surgical indications were degenerative scoliosis, osteoporotic fractures, metastatic tumors, pseudoarthrosis, infections and post laminectomy syndrome. All instrumentation and augmentation procedures were performed through a posterior transpedicular approach. Additional augmentation of un-instrumented vertebrae proximally (UIV +1/+2) was done in 50% of the cases, ‘caudad only’ in 4 cases & and ‘mid only’ in 3 cases. Construct failure occurred in 31 cases, at an average of 328 days from the initial surgery date. Seven cases were associated with trauma and 11 cases presented with a neurologic deficit. The most common modality of failure was osteonecrotic collapse in 20 cases; proximal construct failure occurred in 22 instances, and there was evidence of haloing at the screw-bone-cement interfaces in 22 out 25 cases. 65% (20 out of 31 cases) required revision surgical procedures within an average of 453 days. Conclusion: Failure of instrumented spinal fusion constructs occurred in 25.8% of patients with CAPSI-spinal fusion constructs, 65% (20 out of 31) of which required revision surgical procedures. The high occurrence of osteonecrotic collapse and haloing at the screw-cement-bone interfaces in the failed constructs could likely represent a relationship with construct failure. Isador Lieberman 1 , Stanley Kisinde 1 , Blake Bowden 1 1 Texas Back Institute, Frisco, United States Introduction: Staged reconstructive spine surgical procedures are routinely performed for patients with multilevel degeneration and degenerative deformity of their spine, whose symptoms are refractory to conservative measures. In such complex cases, determining the most appropriate extent of surgical treatment is challenging, including projecting the amount of correction achieved with the interbody stage and the optimal posterior surgery after the interbody stage. Careful evaluation between stages provides an opportunity to optimize the second stage involving posterior procedures. Material and Methods: Retrospective Chart Review of Adult Spine Deformity patients that underwent staged spinal reconstruction surgical procedures from 2016 to 2021 by a single experienced surgeon. We collected pre-, intra- and post-operative data including the initial operative plan, the executed plan, and any alterations that were made to the initial pre-operative plan between the staged surgical procedures. Results: 159 patients underwent staged reconstructive spinal surgery. F:M ratio was 2:1, mean age 64.6 years (33 - 80) and mean BMI 27.43 (17.57 - 40.77). The most common surgical indication was degenerative deformity, followed in descending order of frequency by adjacent segment disease, infection, and pseudarthrosis. About 60% of these patients had undergone at least one prior spine surgical procedure. The most common surgical approaches for the initial and second stage procedures were an anterior lumbar interbody fusion via a left-sided retroperitoneal approach and a posterior midline approach respectively. The average number of days between these procedures was 5. The initial operative plan was altered in 31.4% of patients (n = 50); this resulted in less extensive surgical procedures, including conversion to minimally invasive posterior percutaneous approaches, in up to 90% of these patients with altered plans. The remaining patients had persistent, worsened or new clinical symptoms, requiring a more extensive 2nd stage surgical approach. Conclusion: While traditionally, staging of complex reconstruction spinal surgery may have been due to risk factors related to operative time, anesthesia time, and/or blood loss, the results of this study found an additional benefit of the opportunity to alter the initial surgical plan - in 31% of cases - for the second stage. In the majority of these cases, the alteration resulted in a less extensive procedure. Staging complex procedures, and carefully evaluating patients between the stages allows for optimization of the second stage. Additional investigation is warranted to determine the implications of this finding on cost and complications/re-operations. Achref Abdennadher 1 , Rabie Ayari 1 , Manai Mohamed 1 , Khaled Khlil0 1 , Khalil Amri 1 1 Military Hospital of Tunis, Tunis, Tunisia Introduction: Adult spinal deformity surgery remains a challenge for surgeons, especially executing preoperative surgical planning into reality. The medical industry has developed pre-curved “patient-specific” spinal rods which are created specifically for each patient to obtain a well-defined post operative sagittal balance. The aim of this study was to evaluate the immediate post operative deformity correction and sagittal alignment using specific rods compared to preoperative planning and at a 2-year postoperative follow-up. Material and Method: We conducted a prospective study that included adult patients operated on for dorsolumbar scoliosis with vertebral instrumentation of more than 5 levels. Radiological assessment was carried out on EOS-type full spine exams postoperatively ( 2 years) and compared with preoperative planning. The normative values were determined according to patient age and Pelvic Incidence. Results: 40 patients were included (mean age 67.5YO) with a mean follow-up of 46months (range 24-96 months). The mean pelvic incidence was 50.28° (± 12.4), the mean number of instrumented vertebral levels was 10.73 (± 3.32), 15% had a transpedicular osteotomy. In the immediate postoperative period, there was a mean difference of 4.5° between planned vs. postoperative lordosis (p = 0.18), 10.59° (p < 0.001) between planned vs. postoperative PT, 7.57° (p < 0.001) between planned vs. postoperative thoracic kyphosis and 42.12 mm between planned vs. postoperative VAS (p < 0.001). As for lumbar lordosis: On average, it increased from 28.12° (SD = 18.99) preoperatively to 49.72° (SD = 12.24) postoperatively. The planned lumbar lordosis tended to overestimate the normative lordosis for the patient's age and pelvic incidence (mean difference = 4.25° (p = 0.037). There was no significant difference between planned and postoperative lumbar lordisis (mean difference = -3.27° (p = 0.176). We noted a mean loss of lordosis of 5.52° at the 2 year-follow-up compared with immediate post-operative results (p = 0.049). Conclusions: The use of patient-specific rods for the correction of large adult spinal deformities allows good execution of the preoperative planning and a considerable gain in operative time. Correction of lordosis requires specific analysis to improve postoperative results. Stanley Kisinde 1 , Isador Lieberman 1 , Gregory Fasani-Feldberg 1 1 Texas Back Institute, Scoliosis & Spine Tumor Center, Frisco, United States Introduction: Pelvic fixation has gained popularity in spine surgery for its use during long fusions extending to the sacrum, correction of flat-back, pelvic obliquity and high-grade spondylolisthesis deformities, sacrectomy, sacral fractures with spinopelvic dissociation, and lumbosacral fusion in the setting of substantial osteoporosis. Single S2 alar-iliac (S2AI) screws across the SIJ have been used and described previously, but the stacked bedrock configuration helps to even further offset the exceedingly large forces across the lumbosacral fusion in such constructs. The purpose of this study was to investigate the feasibility of S1AI and S2AI screws placement under robotic guidance in a stacked bedrock configuration and the accuracy of this procedure. Material and Methods: We reviewed medical records of all patients who underwent lumbopelvic fixation with stacked S1AI and S2AI screws utilizing robotic-guidance between June, 2022 and December, 2023. Screw placement and deviation from the preoperative plan were assessed using the robotic system’s planning software intraoperatively by secondary registration or re-registration. Following the robotic-guided, computer-assisted placement of S1AI and S2AI screws, two additional X-ray images – anterior-posterior and oblique fluoroscopic images – were obtained and re-registered with the pre-operative CT images and planned screw trajectories. By toggling between the postoperative fluoroscopic re-registration images and the planned screw trajectories, we assessed deviation of the implanted screws from the planned screw trajectories. Once a satisfactory fusion of the imaging was achieved, screw accuracy (reported as deviation of the screws from the pre-operatively planned trajectories) was assessed by an experienced technician. Patient demographics and intra-operative technical errors, complications and other parameters were also recorded. Results: A total of 108 S1AI and S2AI screws were successfully placed in 27 patients (17F, 10M) under robotic guidance in a stacked bedrock configuration. The overall accuracy was within 1.61 ± 1.56 mm in all planes. There were no intra- or post-operative complications related to the placement of the implants. 3 lateral iliac cortical breaches were identified on post-op CT images but with no further clinical consequences as they only invaded the bulk mass of the gluteal mm. Conclusion: Robotic-guided placement of S1/S2AI bedrock implants in a stacked bedrock configuration is feasible with clinically acceptable results. Secondary registration and intra-operative assessment of screws may help to avoid the need for revision surgery related to misplacement of the implants. Stanley Kisinde 1 , Isador Lieberman 1 1 Texas Back Institute, Scoliosis & Spine Tumor Center, Frisco, United States Introduction: Globally, the population is ageing and spine surgeons are treating more adult spine deformity patients with comorbidities such as diabetes, hypertension, obesity, and vascular disorders resulting in calcification of the major vasculature. These represent risk factors for complications associated with anterior lumbar interbody fusion (ALIF). The purpose of this study was to compare the complication rates of patients 65 years of age or less to those over 65 years who underwent ALIF as part of a staged anterior-posterior reconstruction. Material and Methods: We reviewed a prospectively maintained surgical database to identify patients who underwent ALIF as part of a staged anterior-posterior reconstruction. We mined the database for patient demographics, type of surgery in terms of levels of discectomy and fusion, blood loss, procedure time, complications, length of hospital stay, and discharge disposition. Results: A total of 101 patients between the ages of 20 - 80 years (mean 61.75 years) had undergone the procedure, and the greatest number of levels fused anteriorly was four. The indications for surgery included: in descending order, scoliosis, degenerative disc disease, spondylolisthesis, adjacent segment degeneration, post laminectomy syndrome, and infection. On univariate analysis, only operative time was significantly lower in the older group, which also had a lower mean BMI. There were 2 complications - 4% rate - in each of the groups directly related to the ALIF procedure: a minor surgical vein tear and abortion of the procedure due to inadequate exposure in the ≤ 65 yr-age group, while a chronic anterior abdominal wall wound infection & dehiscence and revision for an undersized ALIF cage occurred in the > 65 yr-age group. Conclusion: The morbidity associated with anterior exposure for ALIF is similar in patients > 65 years compared with younger patients. However, surgeons contemplating anterior approach surgery in older patients need to carefully evaluate the potential for added risk factors and formulate the treatment plan accordingly, but age alone should not rule out ALIF, if otherwise indicated. Md Anowarul Islam 1 1 Bangabandhu Sheikh Mujib Medical University, Spine Division, Orthopedic Surgery, Dhaka, Bangladesh Introduction: The treatment of severe spinal deformities is a demanding and difficult surgical task. Conventional procedures such as posterior and anterior instrumentation or combined anteroposterior instrumentation afford limited correction in rigid neglected or maltreated (fused) deformities. On the contrary, angular osteotomies such as Ponte, Smith Peterson, and Pedicle subtraction osteotomy may not provide the desired amount of correction in very severe deformities with coronal or sagittal plane decompensation. Single stage vertebral column resection (VCR) can be an effective alternative to manage the severe rigid spinal deformities. Materials and Methods: This prospective interventional study which includes 10 cases of kypho-scoliotic deformity, was carried out from March 2021 to December 2023. No. of patients having post-traumatic kyphotic deformity & post tubercular kyphotic deformity were 04 & 06 respectively. All the patients had neurological impairment. Single stage vertebral column resection (VCR) and reconstruction were performed in all these patients. Pre & Post-operatively, neurological assessment was done by the modified Nurick grading system, Scoliosis Research Society-22 and spinal appearance questionnaires. Pain control was assessed by VAS Score. Scoliosis and kyphosis angle were measured by Cobb’s angle measurement method & Overall functional assessment by modified Odom’s score. Results: Average age of the patients was 25 years (range 9-40). Among 10 patients with preoperative gait disturbances, 7 improved to normal gait, 2 remained the same, and 1 showed deterioration to non-ambulatory level. Total SRS-22 scores improved from 3.18 to 3.54 (p5.01), primarily self-image domain. The average kyphotic correction was 15 ± 3.25 ͦ and scoliosis correction was 36 ± 14.19 ͦ. Overall, 54% patients had excellent, 28% had good, 10% had fair and 8% had poor outcome. Conclusion: The ability to correct a rigid deformity in the spine relies on osteotomies. Each osteotomy is associated with a particular magnitude of correction at a single level. Posterior vertebral column resection is the most powerful posterior osteotomy method providing a successful correction of fixed complex deformities. Despite meticulous surgical technique and precision, this robust osteotomy technique can be associated with significant morbidity even in the most experienced hands. Demo Eugenio Dugoni 1 , Federico Iaccarino 2 , Giacomo Pavesi 2 , Alessandro Landi 1 , Pietro Vittorio La Cava 1 , Corrado Iaccarino 2 1 Centro Chirurgico Toscano, Arezzo, Italy , 2 UNIMORE, Modena, Italy Introduction: degenerative dorsolumbar kyphoscoliosis is a complex pathology that can be treated surgically in cases of low back pain that does not respond to conservative treatments and spinal stenosis with neurogenic radiculopathy/claudication. After nerve decompression and spinal stabilization, the restoration of sagittal balance is the most discussed factor in the literature for its correlation with clinical results. Multiple surgical techniques (PLIF, TLIF, ALIF, OLIF, LLIF) and osteotomies (PSO, SPO) are available, proving the current impossibility of demonstrating the superiority of one technique over another in terms of effectiveness. Material and methods: in this single-center retrospective study, 11 patients who underwent PLIF and TLIF performed using expandable cages, posterior decompression and fusion for degenerative kyphoscoliosis of the dorsolumbar spine were evaluated. The period considered goes from 01/01/2021 to 01/07/2024, the surgical procedures were all carried out at Centro Chirurgico Toscano in Arezzo. The inclusion criteria were: patients with spinal deformities in the form of degenerative dorsolumbar kyphoscoliosis with sagittal imbalance (SVA > 50 mm) and symptomatic spinal stenosis. Deformity correction and fusion were indicated in these patients due to the combination of the following factors: progressive radiographic deformity or sagittal imbalance, mechanical low back pain and neurogenic radiculopathy/claudication. The exclusion criteria were: post-traumatic kyphosis or due to compression fractures in cases of osteoporosis and infections. Patients underwent a surgical procedure after failure of conservative therapy (pharmacological/infiltrative/physical) for a period > 6 weeks, associated with a clinic that interfered with normal activities. For sagittal alignment the following were evaluated: sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL). For coronal alignment, the Cobb angle (CA) was evaluated. Results: the post-operative radiological checks and at 1, 3, 6 and 12 months showed the substantial stability of the implant, the spinopelvic parameters fell within normal ranges and the neurological objective examinations remained negative. The orthoses were used for the first post-operative month, at the end of which the patients were able to resume normal activities. The average hospital stay was 5 days, with mobilization during the first post-operative day. The only complication encountered was a case of surgical site infection. Conclusion: the single posterior approach includes all phases of deformity correction and direct decompression of neural structures without having to perform circumferential surgery. The results so far have been satisfactory, both from a radiological and clinical point of view. The limits of this method are linked to the fixity of the deformities, which sometimes does not allow good mobilization of the disc space and to the poor quality of the bone that is often present in patients suffering from this type of pathology. Rohit Bhan 1 , Nisha Kale 1 , Neset Tang 1 , Christopher Diaz 1 , Brian Neuman 1 1 Washington University in St. Louis, Orthopaedic Surgery, St. Louis, United States Introduction: Surgery provides substantial benefit for adult spinal deformity (ASD) patients, supported by improved Scoliosis Research Society (SRS) scores. Minimal clinically important difference (MCID) values indicate clinical improvement, but recovery remains difficult to predict. We aim to identify patient factors that predict MCID for Pain (pMCID) and Function (fMCID) after ASD surgery as a proxy for recovery. Materials and Methods: ASD patients with complete SRS scores for baseline, 6 months, 1 year, and 2 years were included. Upper instrumented vertebrae (UIV) were T1-T11, and lower instrumented vertebrae (LIV) was S1 with pelvic fixation. pMCID and fMCID was set to 0.54 and 0.31 per prior studies. Multivariate analysis of demographics, comorbidities, narcotic use, 5-factor modified frailty index (mFI-5), American Society of Anesthesiologists (ASA) class, fusion levels, surgical factors, and baseline SRS scores were used to predict MCID. Results: We identified a total of 143 patients. There were 89 (62%) primary and 54 (38%) revision surgeries. 119 (83%) patients received all-posterior and 24 (17%) received anterior-posterior surgery. Average number of fusion levels were 11.4 (SD = 3.4), 21 (15%) patients received a 3-column osteotomy, and 36 (25%) patients were revised within 2 years. SRS Pain and Function scores were 2.52 and 2.73 at baseline. At 6 months, 94 patients (66%) met pMCID (+1.40) and 69 (48%) met fMCID (+0.81). On multivariate analysis, no patient factors were associated with meeting both pMCID and fMCID at 6 months, nor either domain individually through 2-year follow-up. When analyzed as a cohort and within groups, SRS domains failed to achieve MCID between 1 year and 2 years, though some were statistically different. Conclusion: Overall, the percentage of patients who meet pMCID and fMCID drop significantly after 6 months. Further, the difference in scores between clinical intervals after 6 months achieved statistical but not clinical difference. This may suggest that recovery captured by SRS scores primarily occurs within 6 months and underscores the similarity of SRS scores between 1 year and 2 years. Patients can be counseled prior to surgery that the majority of improvement will occur within 6 months, with small improvements afterwards. Further studies with larger cohorts may provide better insight into factors promoting recovery within or after 6 months. William Karakash 1 , Maya Abu-Zahra 1 , David McCavitt 1 , Henry Avetisian 2 , Andy Ton 1 , Ishan Shah 1 , Bahador Athari 1 , Jeffrey C. Wang 1 , Raymond Hah 1 , R. Kiran Alluri 1 1 University of Southern California, Los Angeles, United States , 2 Jacobs School of Medicine, Buffalo, United States Introduction: Adult spinal deformity (ASD) surgery involves complex procedures with a high risk of postoperative complications. Osteoporosis is a known modifiable risk factor for complications such as pedicle screw loosening, instrumental failure, and pseudoarthrosis. However, osteoporosis is often underdiagnosed and undertreated in ASD patients. The 2022 best practice guidelines – developed by a multidisciplinary panel of experts – established evidence-based criteria for osteoporosis screening and preoperative management in ASD. As awareness of osteoporosis and its impact on spine surgery has grown, there has been increased emphasis on optimizing bone health preoperatively, although clinical practices remain inconsistent. This study aims to assess the proportion of patients who meet the screening criteria and to evaluate trends in preoperative osteoporosis screening and medical management prior to ASD surgery. Material and Methods: The PearlDiver national database was queried for patients who underwent ASD surgery between 2012 and 2022. Patients were identified using multi-level spinal fusion procedure codes along with a diagnosis of adult spinal deformity. Patients aged < 18 years, with less than two years of preoperative follow-up, or with operative indications for trauma, malignancy, or infection were excluded. The percentage of patients meeting screening criteria was determined using the 2022 best practice guidelines: age over 65, or under 65 with one or more established risk factors. Temporal trends in preoperative X-ray absorptiometry (DXA) screening and osteoporosis treatment were assessed by comparing outcomes between two time periods: 2012-2016 and 2017-2022. Results: The PearlDiver database identified 101,935 patients who underwent ASD surgery, with a mean age of 62.1 (± 13.4) years and 61.7% female. The proportion of ASD patients meeting screening criteria for osteoporosis increased from 70.2% in 2012-2016 to 81.1% in 2017-2022 (p < 0.001). However, among these patients, the percentage who received a DXA scan within 2 years prior to surgery remained low, only increasing from 15.8% to 16.2% (p = 0.15). The percentage of patients with a preoperative diagnosis of osteoporosis increased (13.4% vs 17.0%, p < 0.001), as well as the average age (61.0 vs 63.0, p < 0.001), and length of stay (4.2 ± vs 5.4, p < 0.001). The proportion of osteoporotic patients who received anti-resorptive or anabolic medical management declined preoperatively (23.3% to 21.1%, p < 0.001) and post-operatively (13.3 to 11.6%, p = 0.002). Conclusion: This study underscores the ongoing challenges in preoperative osteoporosis screening and bone health optimization for patients undergoing ASD surgery. Despite both growing awareness and prevalence of osteoporosis and its negative impact on ASD surgery outcomes, rates of osteoporosis screening and medical management have remained persistently low over the past decade. As the population of spine surgery patients ages, optimizing bone health before spinal reconstructive surgery will become increasingly important. Spine surgeons should recognize that osteoporosis is often undiagnosed and untreated in adults undergoing reconstructive spine surgery. Coordinated efforts are thus critical in developing standardized practices for preoperative screening and management of osteoporosis to improve surgical outcomes. Achref Abdennadher 1 , Rabie Ayari 1 , Manai Mohamed 1 , Khaled Khlil0 1 , Khalil Amri 1 1 Military Hospital of Tunis, Tunis, Tunisia Introduction: Most surgeons use functional scores to assess post-operative results of spinal surgery. Patient satisfaction is an objective criterion of success. The aim of this work was to investigate whether there were predictive factors assessing the patient postoperative outcome as “Excellent” or “Poor”. Material and Method: We carried out a retrospective descriptive study spanning 6 years from 01/01/2018 to 31/05/2023 including adult patients who had undergone spinal surgery and who had completed the satisfaction questionnaire. We excluded emergency cases. We divided patients into two groups: Patients judging their outcome as “Excellent” (group A) and those judging their outcome as “Poor” or “Worse” (group B). Data collection was performed by means of electronic questionnaires. Within each group, we looked for correlations with demographic and socio-professional factors, the type of surgery performed, the occurrence of a complication, and finally functional and self-evaluation scores for preoperative pain. Fisher and Wilcoxon tests were used for statistical analysis. Results: 520 patients were analyzed. 450 had completed the post-operative satisfaction questionnaire. 250 patients were included: 208 in group A and 42 in group B. The remaining patients who rated their results as “GOOD” or “FAIR” were not analyzed. Patients in group B had significantly different characteristics from those in group A in terms of the following parameters: a higher proportion of smokers (12% vs 5%, p = 0.05), a higher incidence of dural tear (9.6%, vs. 2.4%, p = 0.03) and a lower preoperative functional score (18 vs. 46). The variations in VAS-L, VAS-R and ODI required to achieve an excellent result were 74, 72 and 80% respectively. Responses to questions 1, 6 and 8 of the Oswestry questionnaire (pain intensity, standing, sex life) and question 7c of the SF-12 were significantly correlated with patient satisfaction. Conclusions: Automated data collection enables us to identify factors predictive of the postoperative outcome of spinal surgery. Active smoking and the occurrence of a dural tear are associated with an increased risk of a poor outcome. Depression, the impact of preoperative pain on the patient's ability to stand up and on his or her sex life are also predictive of excellent or poor postoperative outcome. However, these results need to be validated on a larger scale by pooling data available in open source. Achref Abdennadher 1 , Rabie Ayari 1 , Manai Mohamed 1 , Khaled Khlil0 1 , Khalil Amri 1 1 Military Hospital of Tunis, Tunis, Tunisia Introduction: Surgical site infection (SSI) is the most frequent complication following posterior spinal arthrodesis. Numerous risk factors have been identified in the literature. However, certain parameters, such as the addition of local antibiotics at the end of the procedure, remain of uncertain influence regarding the occurrence of such complication. The aim of our study was to evaluate the risk factors of SSI after posterior vertebral arthrodesis in adults. Material and Method: We conducted a retrospective study including patients operated on for posterior vertebral arthrodesis from 2016 to 2022. The occurrence of an SSI, its delay and the germs responsible were collected. The influence of several clinical and surgical parameters on the occurrence of SSI was assessed by calculating odds ratios. Results: Of 358 patients operated on during the inclusion period, the records of 280 patients were included (mean age 58 years). We included all degenerative pathologies operated on by posterior instrumentation. Post-traumatic instrumentation was excluded. The overall infection rate was 7.1%, with a median delay of 25 days. The most common germ found was methicillin-sensitive Staphylococcus Aureus (60%). The number of spinal levels operated on was a risk factor for infection (greater than 5: 18%, less than 5: 5%, p = 0.004), as was the duration of the operation (9% vs. 1%, p = 0.004). Placement of vancomycin in the operating site at the end of the procedure had a protective effect in the overall series (2% vs. 11%, p = 0.008). Conclusions: This retrospective series confirmed that the use of powdered antibiotics in the operating site significantly reduces the incidence of SSI after posterior vertebral arthrodesis in adults. The number of instrumented stages and the duration of the operation are risk factors for postoperative infection. Ahmad Kareem Almekkawi 1 , Dylan Glaser 1 , James P. Caruso 2 , Salah Aoun 3 , Carlos Bagley 1 1 Saint Luke's Hospital, Neurosurgery, Kansas City, United States , 2 NYU Langone, Orthopedic Surgery, New York, United States , 3 UT Southwestern, Neurosurgery, Dallas, United States Background: Spinal deformities, particularly those affecting the cervical and lumbar regions, are a significant cause of pain and disability in adult populations. The ligamentum flavum, a key anatomical structure in the spinal canal, has been implicated in the pathogenesis of spinal stenosis and related conditions. Thickening of the ligamentum flavum can lead to compression of neural structures, resulting in various clinical symptoms. However, the relationship between ligamentum flavum thickness and different types of spinal deformities remains incompletely understood. Recent advancements in medical imaging and machine learning techniques offer new opportunities to analyze and categorize spinal pathologies. Machine learning clustering algorithms, in particular, have shown promise in identifying patterns and subgroups within complex medical datasets. By applying these advanced analytical methods to measurements of ligamentum flavum thickness, we aim to develop a novel approach for categorizing patients with spinal deformities, potentially leading to more targeted treatment strategies and improved clinical outcomes. Methods: Ligamentum flavum thickness measurements were collected at multiple spinal levels ranging from T4-S1. The thickness classifications were determined using the mean and standard deviation of measurements at each spinal level and were categorized into normal, mild, and severe thickening and plotted on a bell curve. Several machine learning models used demographic variables and thickness measurements from the dataset for training and testing. Machine learning model performance was compared using accuracy, precision, recall, F1-score, and ROC-AUC on the testing dataset. Results: A total of 54 patients with adult spinal deformity were included in this study. The thickness of the ligamentum flavum at each level was calculated using the mean and standard deviation of each measurement at each level (L4-L5 mean thickness = 3.34 mm [95% CI 3.12, 3.57]). Thickness at each level was classified into three categories: Normal, Mild, and Severe. At the L4-L5 level, normal ligamentum flavum thickness was classified as 3.89 mm. The percentage of patients included in our study who fell into each threshold was; Normal = 43.4%, Mild 35.8%, and Severe = 20.8%. Multiple machine learning models were evaluated on their ability to classify ligamentum flavum thickness. The Gradient Boosting Model performed the best with an Accuracy = 0.82, Precision = 0.82, Recall = 0.82, F1 Score = 0.81, and an ROC AUC = 0.93. Conclusion: This study demonstrates the potential of machine learning techniques, specifically clustering algorithms, in categorizing patients with spinal deformities based on ligamentum flavum thickness. The Gradient Boosting Model's high performance (Accuracy = 0.82, ROC AUC = 0.93) in classifying ligamentum flavum thickness suggests that this approach could be a valuable tool in the assessment and management of spinal stenosis and related conditions. William Karakash 1 , Henry Avetisian 1 , Jeffrey C. Wang 1 , Raymond Hah 1 , Ram Alluri 1 1 Keck School of Medicine of USC, Department of Orthopaedics, Los Angeles, CA, United States Introduction: Spinal osteotomy encompasses various surgical techniques designed to correct spinal deformity, with Smith-Petersen Osteotomy (SPO) and Pedicle Subtraction Osteotomy (PSO) being the most prominent. SPO removes posterior spinal elements for ∼10° correction per level, while PSO excises a larger wedge including pedicles for ∼30-40° correction in one level, offering greater deformity correction but with increased surgical complexity. Both techniques restore spinal sagittal and coronal alignment through posterior column modification. As the population ages and the importance of spinal balance continues to gain recognition, the use of osteotomies has increased. This study examines the utilization trends of SPO from 2010 to 2022, comparing them with PSO trends over the same period. Material and Methods: A retrospective analysis using Current Procedural Terminology (CPT) codes was conducted with the PearlDiver Mariner database to identify patients who underwent SPO (CPT-22210, 22212, 22214, 22216) and PSO (CPT-22206-22208) from 2010 to 2022. Patients with adult spinal deformity (ASD) were identified using International Classification of Disease, 9th and 10th Edition (ICD-9, ICD-10) codes. These patients were further stratified by spinal segment (cervical, thoracic, lumbar) and by single- or multi-level procedures. Annual utilization rates between these groups were then compared. Results: From 2010 to 2022, the utilization rates of SPO significantly increased across all spinal regions (+125%). Single-level SPO utilization rose markedly in the cervical (+73.2%), thoracic (+44.8%), and lumbar (+188.5%) regions. Similarly, multilevel SPO utilization demonstrated substantial increases in the cervical (+90.0%), thoracic (+104.3%), and lumbar (+105.6%) regions. In contrast, PSO utilization grew by only 14.5% during the same time period, with single level PSOs increasing 30.9% and multilevel PSOs decreasing 39.44%. Conclusion: The significant rise in SPO utilization, especially in single-level lumbar (+188.5%), indicates its growing popularity in spinal deformity surgery and its effectiveness in achieving spinal alignment with potentially fewer complications. The increase in multilevel SPO usage further emphasizes its role in complex spinal reconstructions. Although PSO utilization also grew, its slower increase compared to SPO suggests a preference for SPO due to potentially lower morbidity. Reimbursement factors may also contribute to this trend, as small posterior osteotomies previously overlooked are now billed as SPOs for higher total reimbursement. Moreover, a three-level SPO offers higher physician compensation than a single-level PSO while achieving similar total correction. These trends highlight the need for ongoing research to refine patient selection and surgical techniques, and to assess the long-term outcomes and economic impact of increased SPO and PSO use. Jiri Skala-Rosenbaum 1 , Jakub Jezek 2 , Jan Svec 2 , Petr Kafka 3 , Irena Kozakova 3 1 University Hospital Kralovske Vinohrady, Prague, Czech Republic, Orthopaedic and Trauma Department, Prague 10, Czech Republic , 2 University Hospital Kralovske Vinohrady, Prague, Czech Republic, Orthopaedic and Trauma Department, Prague 10 , Czech Republic, 3 University Hospital Kralovske Vinohrady Prague, Czech Republic, Department of Anaesthesiology and Resuscitation, Prague 10, Czech Republic Introduction: Open spinal deformity surgeries are associated with the highest risk of significant blood loss and transfusion. A hidden blood loss is important in the postoperative period, however into the visible amount of blood in the suction bottles during the surgery the blood in the soaked sponges has to be calculated. Out of several methods of blood loss estimation the gravimetric method seems to be most accurate. It is of major importance to be aware about the amount of blood in the gauzes to assess the perioperative real blood loss and react properly in time. Material and Methods: Our prospective study done in 2022-2023 evaluated the blood loss in the sponges in a consecutive group of 28 adult patients (14 man, 14 women) with thoracolumbar spinal deformity, where perioperative blood loss exceeded 1 000ml. A gravimetric method based on the change between dry and soaked sponges was used to assess the real volume of blood to be added to the amount of blood in suction bottles. Results: The average age of patients was 63 years (range 21-83), average BMI was 28.85 (range 19.44-39.45). The average number of operated segment was 5.54 (range 3-12). Only posterior column surgery was performed in 22 cases, 6 surgeries addressed both columns from posterior approach. The mean surgical time was 211 minutes (range 140-290). The average blood loss in suction was 1 375.00 mL and 353.53 mL were hidden in the surgical gauzes, making the total blood loss 1 836.52 mL in average. Thus, the blood loss in sponges represented 25.7% of total perioperative blood loss, but when counting percentage of blood loss in surgical gauze from blood loss visible in the suction canister, the median percentage that had to be added was 28.3%. None of the evaluated parameters were found significant for higher risk of blood loss into the sponges (number of operated segments, age, ASA score, BMI). However, there was a higher risk for hidden blood loss in the sponges in females (32 v. 25%), posterior column surgery only (30 vs. 21%) and surgical time within 180 minutes (33 vs. 27%), and these approached statistical significance. Conclusion: In average, 28.3% has to be added to the visible amount of blood in the suction bottle to find out the total real perioperative blood loss in open adult deformity surgeries. There was a higher risk for increased amount of blood in the soaked sponges in females, posterior column procedures only and for surgeries within 180 minutes, but without any significant difference. Chibuikem Ikwuegbuenyi 1 , Mateusz Bielecki 1 , Yizhou Xie 1 , Jessica Berger 1 , Rodolfo Villalobos 1 , Noah Willett 1 , Mousa Hamad 1 , Ibrahim Hussain 1 , Galal Elsayed 1 , Osama Kashlan 1 , Roger Härtl 1 1 Och Spine at NewYork-Presbyterian/Weill Cornell Medical Center, Department of Neurological Surgery, New York, United States Introduction: Adult degenerative scoliosis (ADS) is a spinal deformity arising from degenerative changes in the spine, leading to abnormal curvature, pain, and reduced mobility. Standard surgical approaches, such as spinal fusion, effectively stabilize the spine but are associated with limitations, including reduced mobility and adjacent segment degeneration. Patients with ADS often develop degenerative lumbar spinal stenosis (DLSS), further complicating spinal stability and treatment. While minimally invasive techniques like tubular unilateral laminotomy for bilateral decompression (tULBD) offer a less invasive alternative, the impact of this approach in patients with both ADS and DLSS remains underexplored. This study evaluates the short-term effects of navigated tULBD on spinal alignment, decompression, and mobility in this complex patient population. Material and Methods: This retrospective single-center study evaluated patients who underwent navigated tULBD between June 2019 and October 2022 for DLSS with ADS. Patients aged ≥ 18 years with DLSS and ADS (global Cobb angle ≥ 10°), with or without grade I spondylolisthesis, were included. Radiological assessments of spinopelvic parameters and global alignment were conducted pre- and post-operatively using AI-powered FXA™ software. Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) were collected. Statistical analysis included the Wilcoxon Signed Rank Test or paired t-test for comparing time points and Spearman's correlation to assess the relationship between radiological and clinical outcomes. Significance was set at p < 0.05, with all analyses performed in R Studio. Results: This study included 20 patients with a mean follow-up of 2 months. The mean age was 74.6 ± 7.6 years, and the mean BMI was 26.08 ± 3.7 kg/m 2 . Patients underwent a median of 2 surgical levels (IQR: 1-3), with the majority (45%) undergoing single-level decompression. Radiological parameters - pelvic incidence (54.8° pre-op vs. 53.8° post-op), pelvic tilt (28.9° vs. 26.3°), sacral slope (31.4° vs. 29.4°), lumbar lordosis (42.8° vs. 42.4°), sagittal vertical axis (34.4 mm vs. 36.2 mm), global Cobb angle (18.6° vs. 19.6°), and segmental Cobb angle (6.0° vs. 5.7°) - did not show statistically significant changes at the latest follow-up (p > 0.05). Clinically, patients showed significant pain relief. The median Back VAS improved from 5 (IQR: 3-9) preoperatively to 2 (IQR: 0-2) postoperatively (p = 0.009) and further to 1 (IQR: 0-4.5) at follow-up (p = 0.004). Similarly, the median Leg VAS decreased from 3.5 (IQR: 0-5) preoperatively to 0 (IQR: 0-3.1) postoperatively (p = 0.02) and remained 0 (IQR: 0-0) at follow-up (p = 0.04). ODI improved from 37.8 (IQR: 29-42.5) preoperatively to 26.7 (IQR: 20-36.7) postoperatively (p = 0.11) and further to 17.5 (IQR: 5-24) at follow-up (p = 0.04). Correlation analysis between radiological parameters and clinical outcomes revealed weak to moderate but nonsignificant associations. Conclusion: This study demonstrates that navigated tULBD is a promising minimally invasive option for patients with ADS and DLSS. The procedure led to significant improvements in pain and disability while maintaining spinal stability without significant changes in spinal alignment. These short-term results suggest that tULBD can effectively address symptoms in this complex population, but longer-term studies are needed to confirm the durability of these outcomes. Sami Bahroun 1 , Anis Bouaziz 1 , Ameur Triki 1 , Mohamed Samih Kacem 1 , Mohamed Samir Daghfous 1 1 Kassab Hspital, Orthopaedic Department B, Tunis, Tunisia Background: Isthmic spondylolisthesis is a common condition that can cause significant lumbar and radicular pain, often requiring surgical intervention. Posterolateral fusion (PLF) and posterior lumbar interbody fusion (PLIF) are two widely used techniques for treating this condition. However, there remains a need to better understand the comparative clinical outcomes and postoperative complications between these two approaches in order to guide surgical decision-making. Materials and Methods: A retrospective comparative study was conducted on 48 patients who underwent either PLF or PLIF for isthmic spondylolisthesis. Data collected included affected levels, patient age, and spondylolisthesis grade according to Meyerding's classification. Clinical outcomes were assessed using the Oswestry Disability Index (ODI) and the Visual Analog Scale (VAS) for both lumbar and radicular pain. Postoperative complications, such as radiculopathies and recurrence of symptoms, were also analyzed. Results: Our study included 48 patients with a mean age of 48.7 ± 6 years, followed for an average of 3 years. The L5-S1 level was affected in 38 patients, L4-L5 in 8 patients, and L3-L4 in 2 patients. According to Meyerding, 39 patients had grade 2 spondylolisthesis, while 9 had grade 1. A total of 28 patients underwent PLIF, and 20 underwent PLF. In the PLIF group, preoperative scores were as follows: ODI: 42.54, VAS lumbar: 6.35, and VAS radicular: 7.85. Postoperatively, these scores improved to ODI: 18.23, VAS lumbar: 1.86, and VAS radicular: 2.54. In the PLF group, the preoperative scores were ODI: 20.75, VAS lumbar: 3.4, and VAS radicular: 2.12. A significant difference was observed only in lumbar VAS scores between the two groups (p = 0.002), while other results were similar. Regarding postoperative complications, 6 patients in the PLIF group experienced immediate postoperative radiculopathy, which improved over time. Symptomatic recurrence occurred in 3 patients in the PLIF group and in 8 patients in the PLF group. Conclusion: Both PLIF and PLF provided satisfactory clinical outcomes in the management of isthmic spondylolisthesis, with a significant improvement in lumbar pain observed in the PLIF group. However, postoperative radiculopathy and symptom recurrence were more common in the PLF group, highlighting the importance of long-term follow-up. Mohammed Moussa 1 , Ahmed Saber 1 1 Fayoum University Hospital, Orthopedic Department, Spine Unit, Fayoum, Egypt Introduction: To report nine cases of multiple-level spondylolysis and evaluate the effectiveness of surgical repair in relieving the patient’s pain scores and improving their quality of life, in addition to exploring possible alternative management plans. Material and Methods: We followed the CONSORT guidelines during the preparation of this study. Patients with multiple-level spondylolysis were included. We compared postoperative lower back pain (LBP), leg pain, and Oswestry disability index (ODI) during a follow-up period of 12 months with baseline values. The pain was assessed using a self-reported visual analog scale (VAS). Other outcomes as operation time, blood loss, and hospital stay were also analyzed. Results: N ine patients (five males and four females) were included in this study. The mean ± SD age was 24 ± 2.96 years. Compared with preoperative data, the LBP-VAS has significantly decreased (p < 0.001) after one day (5.67 ± 0.87), after three months (3.67 ± 0.5), after six months (2.78 ± 0.44), and after one year (1.67 ± 0.5). Leg pain VAS has been reduced to 3.11 ± 1.05 on the first postoperative day, 1.44 ± 1.59 after three months, 0.56 ± 0.53 after six months, and 0.11 ± 0.33 after one year. The mean operative time was 120 ± 37.1 minutes, blood loss was 325.56 ± 53.18 ml, and hospital stay was 5.22 ± 1.2 days. Conclusion: After 12 months of follow-up, surgical repair and preservation of the spine motion are possible with excellent outcomes in patients with two or three-level spondylolysis. Keywords: Spondylolysis, Surgical repair, fusion, spine, orthopedics. Kurt Holuba 1 , Brendan Schwartz 1 , Justin Reyes 1 , Roy Miller 1 , Alexandra Dionne 1 , Gabriella Greisberg 1 , Josephine Coury 1 , Ronald A. Lehman 1 , Zeeshan Sardar 1 , Lawrence Lenke 1 , Joseph Lombardi 1 1 Columbia University Medical Center, New York, United States Introduction: Golf and tennis are popular sports that require spinal flexibility and rotational strength. Fusion of multiple spine levels limits spinal mobility, and may severely impact individuals’ ability to return to these rotational sports. In a cohort of previously active golfers and tennis players who underwent long construct fusion, we report their presentation, operative treatment, and return to play (RTP) process. Methods: A retrospective analysis of consecutive patients who underwent primary or revision spinal fusion, involving consecutive spinal levels from pelvis to T10 or higher, from 2015-2023 was conducted. Patients who were ≥ 12 years old, active golfers or tennis players prior to surgery, and who had minimum of 1-year follow-up were asked to complete a sport-specific questionnaire pertaining to their preoperative and postoperative ability. Active golf/tennis players were defined as having played the sport ≥ 5 times in their life, and having played ≥ 1 time in the 5 years prior to their surgery. The postoperative RTP time, as well as numerous sport-specific metrics were obtained. SRS-22 and Oswestry Disability Index (ODI) scores were collected at baseline and at one year postoperatively. Demographic, presenting, and operative data was also collected. Results: A total of 25 patients were included at a mean follow-up of 5.2 ± 2.1 years, of which 44.0% (n = 11) were golfers, 48.0% (n = 12) were tennis players, and 8.0% (n = 2) were both tennis and golf players. Mean age was 54.2 ± 17.4 years, mean BMI was 24.1 ± 5.5 kg/m 2 , and 76.0% (n = 19) patients were female. 69.2% (n = 9) patients returned to golf at a mean 1.3 ± 0.5 years after surgery. 57.1% (n = 8) patients returned to tennis at a mean 1.5 ± 1.6 years after surgery. Of those that returned to golf, patients maintained or improved their performance in the following metrics: 88.9% (n = 8) in golf ability, 11.1% (n = 1) in handicap, 77.8% (n = 7) in number of days golfing per year, and 100.0% (n = 9) in pain while golfing. Of those that returned to tennis, patients maintained or improved their performance in the following metrics: 75.0% (n = 6) in tennis ability, 87.5% (n = 7) in maximum games per session, 50.0% (n = 4) in number of days playing tennis per week, and 87.5% (n = 7) in pain while playing tennis. 100% (n = 25) of patients improved in their VAS pain score. Conclusions: Most patients undergoing long construct spinal fusion return to golf and tennis. Patients can reasonably expect an equal or improved rotational sport performance after spine surgery. These data provide a baseline for future inquiries into RTP following spine surgery. Riley Sevensky 1 , Zeeshan Sardar 1 , Justin Reyes 1 , Roy Miller 1 , Natalia Czerwonka 1 , Josephine Coury 1 , Oluwademilade Tega 1 , Fthimnir Hassan 1 , Joseph Lombardi 1 , Lawrence Lenke 1 1 Columbia University Medical Center, New York, United States Introduction: Scheuermann’s kyphosis (SK) typically presents with postural abnormality or back pain in adolescents or young adults. Surgical correction is indicated in extreme hyperkyphosis, severe pain, or functional limitation. It has been hypothesized that correction of thoracic kyphosis (TK) should be based on pelvic incidence (PI). This study will identify differences in radiographic and functional parameters of surgically managed SK patients with regards to PI. Methods: The HARMS Study Group database contained SK patients with surgical intervention between 2006 and 2011. Existing preoperative and 2-year postoperative radiographic images, parameters, and patient-reported outcome measures (PROMs) were obtained; supplemental parameters were measured. Unpaired two-tailed t-tests, one-way ANOVA, and chi-squared tests were utilized. Results: Of the HARMS SK cohort [n = 97], we included only patients with available pelvic data [n = 53]. Overall, mean age at surgery was 15.9, baseline TK (T1-T12) was 74.1º, lumbar lordosis (LL, L1-S1) was -69.6º, and PI was 40.2º. Baseline pelvic tilt (PT) [6.7º] and sacral slope (SS) [33.4º] did not differ from postoperative values. Of all patients, 34 [64.2%] had a PI 60° (G3). Age, sex, and body mass index were not different between groups. Due to limited subjects, G3 was excluded from PI group analyses. Among G1 and G2, number of instrumented levels did not differ [12.9 vs 13.0; p = 0.824]. Preoperative TK, postoperative TK, and surgical correction of TK did not differ between PI groups [p = 0.626, p = 0.302, p = 0.530]. Preoperative LL [-64.5 vs -75.6; p = 0.010] and preoperative proximal LL (pLL, L1-L4) [-22.0 vs -29.8; p = 0.026] were greater in G2; preoperative distal LL (dLL, L4-S1) did not differ [p = 0.358]. Postoperative LL, pLL, and dLL did not significantly differ between G1 and G2 [p = 0.060, p = 0.063, p = 0.626]. In line with PI, preoperative and postoperative PT and SS were higher in G2. Preoperative TK-PI mismatch [41.5 vs 22.0; p = 0.0003] and postoperative TK-PI [21.2 vs 1.4; p = 0.0005] were lower in G2. Preoperative SRS pain, general function, and total scores were higher in G1 [p = 0.010, p = 0.043, p = 0.027]; preoperative SRS self-image, mental health, and satisfaction scores did not differ. Postoperative SRS scores were not different between groups. Rates of any junctional kyphosis (JK), proximal JK, and distal JK did not differ between G1 and G2. Of all SK patients [n = 53], 50.9% had any JK, 18.9% had PJK, and 35.8% had DJK. Those with PJK at 2-year follow-up had lower TK correction [-3.7 vs -21.8; p = 0.004] and greater postoperative TK-PI mismatch [26.4 vs 11.4; p = 0.021] than those without. Conclusion: PI for surgically treated SK patients was low. Preoperative TK, postoperative TK, and TK correction were similar regardless of PI. Patients with moderate PI had significantly lower preoperative SRS pain and general function scores but postoperative SRS scores similar to patients with lower PI, indicating that surgical management may equalize PROMs regardless of PI. Notably, patients developing PJK were found to have a lesser degree of TK correction and higher postoperative TK-PI mismatch. Riley Sevensky 1 , Zeeshan Sardar 1 , Justin Reyes 1 , Josephine Coury 1 , Oluwademilade Tega 1 , Fthimnir Hassan 1 , Joseph Lombardi 1 , Lawrence Lenke 1 1 Columbia University Medical Center, New York, United States Introduction: Scheuermann’s Kyphosis (SK) is characterized by rigid hyperkyphosis of the thoracic or thoracolumbar spine in adolescents or young adults. This study will examine the baseline radiographic parameters of SK patients in comparison with a normative cohort in order to investigate the inherent differences in the structural anatomy of SK prior to surgical intervention. Material and Methods: The HARMS Study Group patient database was queried to extract data on SK patients with preoperative visits between 2006 and 2011. The SK cohort consisted of 97 total patients; we included only patients with available pelvic parameter data [n = 53]. This SK cohort was compared with a prospectively enrolled multi-ethnic alignment normative study (MEANS) patient cohort. The MEANS database consisted of 467 total asymptomatic patients from five different countries; we included only patients age < 40 to promote meaningful comparison with the young HARMS cohort [n = 254]. Existing HARMS preoperative and MEANS baseline radiographic imaging and parameters were obtained; supplemental radiographic fields were measured from images. Unpaired two-tailed t-tests and chi-squared tests were utilized to determine significance. Results: At baseline, the SK cohort (SK; n = 53) had a greater mean body mass index (BMI) [26.7 vs 23.1; p = 0.00003] than the normative cohort (MEANS; n = 254). As expected, baseline thoracic kyphosis (TK, T1-T12) measurements were significantly higher in SK than in MEANS [74.1 ± 12.4 vs 41.9 ± 10.2; p < 0.00001]. Cervical sagittal angle (CSA, C2-C7) [-18.1 vs 2.3; p < 0.00001] and T1 slope (T1S) [37.7 vs 21.5; p < 0.00001] were significantly greater in SK than MEANS. All SK lumbar measures, including lumbar lordosis (LL, L1-S1) [-69.6 vs -57.3; p < 0.00001], proximal LL (pLL, L1-L4) [-25.5 vs -20.1; p = 0.00008], and distal LL (dLL, L4-S1) [-44.1 vs -37.3; p < 0.00001], were significantly higher than MEANS. In contrast, SK pelvic parameters were significantly lower than MEANS in terms of pelvic incidence (PI) [40.2 vs 50.6; p < 0.00001], pelvic tilt (PT) [6.7 vs 10.8; p = 0.00007], and sacral slope (SS) [33.4 vs 39.7; p < 0.00001]. Conclusion: As anticipated, baseline TK in SK was significantly higher than the norm. Despite the high TK, PI and PT were found to be significantly lower in SK than in MEANS, suggesting fundamental differences in the pelvis. When compared with MEANS, SK was also found to have significantly greater CSA and T1S as well as higher LL, pLL, and dLL, reflecting considerable cervical and lumbar compensation, respectively. The global sagittal alignment in SK patients is inherently different at baseline than that of a young asymptomatic population. Riley Sevensky 1 , Zeeshan Sardar 1 , Justin Reyes 1 , Josephine Coury 1 , Oluwademilade Tega 1 , Fthimnir Hassan 1 , Joseph Lombardi 1 , Lawrence Lenke 1 1 Columbia University Medical Center, New York, United States Introduction: Scheuermann’s Kyphosis (SK) is a developmental deformity identified by rigid thoracic hyperkyphosis; surgical indications include severe kyphosis and pain. This study will examine the radiographic differences between SK patients and a normative cohort matched on pelvic parameters to investigate the divergence of SK patients before and after surgery. Methods: The HARMS Study Group database consisted of 97 total SK patients with surgical intervention between 2006 and 2011; we included only patients with available pelvic parameters [n = 53]. The prospectively enrolled multi-ethnic alignment normative study (MEANS) database consisted of 467 total patients; patients age < 40 were included to promote meaningful comparison with the young HARMS cohort [n = 254]. A 1:1 propensity score match (PSM) with optimal parameters was conducted to control for preoperative pelvic incidence (PI) and pelvic tilt (PT) between SK cases and normative patients. Post-match standardized mean difference [0.1997] and variance ratio [1.6998] were acceptable. SK data included preoperative and 2-year postoperative timepoints; normative data included only baseline values. Wilcoxon rank sum tests and McNemar’s tests were utilized to determine significance. Results: Of 53 HARMS and 254 MEANS patients, PSM generated 53 matched pairs. By design, PI and PT did not differ between preoperative SK (preSK) patients and the normative cohort [40.2 vs 41.8; p = 0.366 and 6.7 vs 6.3; p = 0.587]. At baseline, sex breakdown and BMI did not differ between preSK and MEANS [p = 0.742, p = 0.395]. As expected, thoracic kyphosis (TK, T1-T12) in preSK was significantly higher than MEANS [74.1 vs 41.6; p < 0.00001]. Preoperative cervical sagittal angle (CSA, C2-C7) [-18.1 vs 2.7; p < 0.00001] and T1 slope (T1S) [37.7 vs 22.0; p < 0.00001] were significantly greater in preSK than MEANS. All preSK lumbar measures, including lumbar lordosis (LL, L1-S1) [-69.6 vs -52.8; p < 0.00001], proximal LL (pLL, L1-L4) [-25.5 vs -15.6; p < 0.00001], and distal LL (dLL, L4-S1) [-44.1 vs -37.1; p = 0.0002] were significantly higher than MEANS. As with matched pelvic parameters, sacral slope (SS) did not differ between cohorts [33.4 vs 35.4; p = 0.220]. At 2-year follow-up after surgical intervention, TK remained significantly higher in the postoperative SK cohort (postSK) compared with MEANS [56.5 vs 41.6; p < 0.00001]. CSA [-8.0 vs 2.7; p = 0.0009] and T1S [34.1 vs 22.0; p < 0.00001] also remained significantly greater in postSK than MEANS. In contrast, all postSK lumbar parameters normalized towards MEANS, including LL [-53.3 vs -52.8; p = 0.930], pLL [-16.6 vs -15.6; p = 0.603], and dLL [-36.7 vs -37.1; p = 0.780]. Postoperative pelvic parameters, including PI [p = 0.578], PT [p = 0.189], and SS [p = 0.884] remained similar between postSK and MEANS. Conclusion: In comparison with a young asymptomatic MEANS cohort matched on PI and PT, the preoperative spinal parameters spanning from the cervical to lumbar spine in surgically treated SK patients were significantly different, reflecting compensation for extreme TK. Following surgical intervention, SK TK remained significantly higher than MEANS. Compensatory thoracic and cervical parameters regressed towards the norm but remained significantly different whereas postoperative lumbar parameters normalized and did not differ from asymptomatic patients, suggesting that TK correction may not require complete return to the norm in order to relieve lumbar hyperlordosis. Cesar Carballo 1 , Molly Monsour 2 , Samantha Schimmel 2 , Petra Allen 2 , Jay I. Kumar 1 , Bryan Clampitt 2 , Puya Alikhani 1 , Diego Soto Rubio 1 1 Department of Neurosurgery and Brain Repair, University of South Florida, Morsani College of Medicine, Tampa, United States , 2 USF Health Morsani College of Medicine, Tampa, United States Introduction: Adult spinal deformity (ASD) correction surgery aims to improve function, alleviate pain, and restore biomechanical alignment. However, the risk of revision surgery remains a significant concern, with reported rates ranging from 7% to 47% (Pitter, 2018). Identifying the key factors that lead to revision surgery is crucial for better preoperative planning and postoperative management and for reducing the likelihood of secondary procedures. Material and Methods: We conducted a retrospective review of all ASD correction surgeries (n = 266) performed at our tertiary care center between 2016 and 2023. ASD correction surgery was defined as surgeries with an upper instrumented vertebrae (UIV) at L2 or higher and a lower instrumented vertebrae (LIV) extending to the pelvis. Postoperative complications, including hardware failures (HF) such as screw and rod fractures or pullouts, proximal junctional kyphosis (PJK), proximal junctional failure (PJF), and the need for revision surgery, were analyzed. Only patients requiring revision surgery were included in the analysis. Results: Of the 266 ASD patients, 37 (14%) required revision surgery (M: 24; F: 13). The mean age of the revision cohort was 64 years (± 9.53). UIV distribution showed 20 (8%) patients at T4, 116 (44%) at T10, and 130 (48%) at L2. Hardware failure was the most common reason for revision, accounting for 26 cases (70%). Etiologies of HF included rod fractures (46%), screw pullout (27%), screw fractures (1%), and rod pullout (0.4%). Additionally, 12 patients (32%) with HF had associated PJK, while 3 patients (8%) experienced PJF. The average time to revision surgery was 20 months postoperatively. Conclusion: Revision surgery remains a recognized risk following ASD correction, with hardware failure and symptomatic PJK being the most significant contributors. Understanding these key risk factors can improve surgical planning and patient outcomes, ultimately helping to reduce the revision surgery rate in ASD patients. Hamisi Mraja 1 , Baris Peker 2 , Tunay Sanli 1 , Sepehr Asadollahmonfared 1 , Enas Daadour 1 , Mehmet Zamanoglu 1 , Onur Levent Ulusoy 1 , Selhan Karadereler 1 , Meric Enercan 2 , Azmi Hamzaoglu 1 1 Scoliosis and Spine Center - Istanbul, Turkye , 2 Demiroglu Bilim University, Istanbul, Turkye Introduction: The main goal of the surgical treatment in adult spinal deformity is to restore of the ideal lumbar lordosis (LL) and sagittal balance. In the presence of a mobile disc, complete bilateral facetectomy and discectomy provide more flexibility and sagittal plane correction at the thoracolumbar and lumbar regions. The aim of this study is to compare the outcomes of multi-level interbody fusion with bilateral facetectomy (BF) vs multi-level unilateral TLIF (UT) for the restoration of thoracolumbar and lumbar sagittal alignment. Material and Methods: 26 patients (11F, 15M), mean age 63 (36-77) years who underwent a multi-level interbody fusion with bilateral facetectomy were compared with 26 patients (12F,14M), mean age 65 (39-78) years who underwent multilevel unilateral TLIF procedure. Coronal and sagittal parameters were measured on preop and f/up x-rays. Clinical assessment was done with ODI and VAS. Results: Mean f/up was 43m for bilateral facetectomy, 49m for multi-level unilateral TLIF group. Mean interbody fusion levels were 2.9 (2-5) for bilateral facetectomy and 2.75 (2-5) for multi-level unilateral TLIF groups. Preop PI-LL mismatch was greater indicating the larger lordosis need for BF group (23° vs 12°). Preop lumbar lordosis of 27.5 was restored to 48.3(75%) in BF group. Preop lumbar lordosis of 40.8 was restored to 48.2 (18%) in UT group. Segmental lordosis and overall lumbar lordosis improved significantly in both groups (p < 0.05). BF group showed significantly greater improvement in segmental lordosis and achieved more overall lumbar lordosis compared to UT group (p < 0.01). The mean segmental lordosis increase per interbody fusion level was 7.44° for BF vs 3.34° for UT group (p < 0.01). The segmental lordosis contribution was greater at T12-L1, L1-L2, and L2-L3 than at other levels. ODI and VAS scores improved significantly in both groups. Conclusion: Multi-level interbody fusion with bilateral facetectomy provided greater improvement in segmental lordosis (BF:7.44°vsUT:3.34° per level) than multi-level unilateral TLIF. Overall lumbar lordosis significantly improved with multi-level interbody fusion with bilateral facetectomy (p < 0.01). Greater correction of thoracolumbar and LL sagittal balance was achieved when interbody fusion was performed at T12-L1, L1-L2, and L2-L3 levels (p < 0.05). When interbody fusion with bilateral facetectomy is performed at 3 or more levels, it can serve as an alternative technique to 3-Column Osteotomy for the restoration of thoracolumbar and lumbar sagittal alignment in adult spinal deformity. Ryan Turlip 1 , Mert Dagli 1 , Yohannes Ghenbot 1 , Daksh Chauhan 1 , Hasan Ahmad 1 , Kevin Bryan 1 , Jaskeerat Gujral 1 , William Welch 1 , Ali Ozturk 1 , Jang Yoon 1 1 University of Pennsylvania Perelman School of Medicine, Philadelphia, United States Introduction: When performing circumferential spinal fusion for adult spinal deformity (ASD), the procedure may be performed same-day or staged. The decision whether to stage these procedures is typically guided by the operating surgeon's preference, influenced by the procedural complexity and patient-specific considerations. Objectives: This study aimed to investigate differences in outcomes between same-day and staged circumferential spinal fusion for ASD correction. Methods: In accordance with the PRISMA-P guidelines, our protocol was recorded on PROSPERO (CRD42022339764) and disseminated (PRR1-10.2196/42331) during the initial trial phase. We developed our inclusion criteria based on the PICO (population, intervention, comparison, outcome) framework. The population of interest comprised adults diagnosed with ASD. The intervention in question was the staged circumferential spinal fusion. The comparison was same-day circumferential spinal fusion. Evaluated outcomes included operative duration, estimated blood loss quantified in milliliters, intraoperative and perioperative complications, hospital and intensive care unit lengths of stay, rates of surgical revision, hospital readmissions, and patient-reported outcomes (PROs). Comprehensive literature searches were conducted on MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and Scopus. The results were exported to Covidence. Screening, quality assessment, and data extraction were independently conducted by two reviewers, with a third reviewer resolving any conflicts. Quantitative synthesis was carried out using RevMan Web provided by Cochrane. Results: From the initial 5200 studies examined, 7 met the criteria for our qualitative synthesis, with 4 qualifying for our quantitative assessment through meta-analysis. The meta-analysis revealed a longer hospital stay for the staged surgery cohort (mean difference 5.1 days, 95% Confidence Interval [CI] 2.17-8.02, p < .001). No statistically significant disparities were observed in estimated blood loss, intraoperative complications, wound infection rates, postoperative complications, perioperative complications, rates of reoperation, or instances of readmission. Conclusions: The meta-analysis indicated an increased LOS for patients undergoing staged circumferential spinal fusion to correct ASD. No significant differences were noted in estimated blood loss (EBL), peri-operative complications, wound infection rates, incidence of reoperation, and hospital readmissions. Cristian Ricardo Correa Valencia 1 , Sebastián Oyanedel Pérez 1 , Matias Nahuelpan Sanhueza 1 , Diego Contreras 1 , Ignacio Echeverria 1 1 Universidad de la Frontera, Temuco, Chile Introduction: Anterior Lumbar Interbody Fusion (ALIF) with percutaneous fixation (PF) is an advanced surgical technique that has gained popularity in treating high-grade spondylolisthesis due to its benefits, such as reducing direct nerve manipulation, minimizing posterior muscle damage, and lowering intraoperative blood loss. However, its use in high-grade spondylolisthesis remains limited in the literature. Furthermore, the importance of venous anatomy in the surgical planning of these procedures has been emphasized. This report describes the experience in treating two cases of high-grade spondylolisthesis using ALIF with PF, focusing on surgical times, radiological outcomes, and intraoperative complications. Material and Methods: Two patients with high-grade L5-S1 spondylolisthesis (15 and 56 years old) who did not respond to prior conservative treatment were included. Both underwent ALIF with PF, and data on demographics, surgical times, and intraoperative complications were collected. Radiological evaluation included pre- and postoperative dynamic X-rays to measure lumbopelvic parameters. Pain and functional disability were assessed using the Visual Analog Scale (VAS) and the Oswestry Disability Index (ODI) before and after surgery. In neither case was the intervention of vascular or access surgeons required. Results: The patients (one female, one male) had an average surgical time of 5 hours and 28 minutes (range: 5:06-5:50 hours). During interbody distraction in one case, an injury to the middle sacral artery occurred, which was effectively controlled with the placement of hemostatic clips. The second patient developed postoperative radiculitis without motor deficit, which was successfully treated with a nerve block, showing favorable progress. No major complications were recorded post-surgery. Postoperative X-rays demonstrated correct implant placement and restoration of lumbopelvic parameters. Both patients reported significant improvements in VAS and ODI scores, indicating a notable reduction in pain and disability. Conclusion: The ALIF technique combined with PF proved to be a safe and effective surgical alternative for treating high-grade spondylolisthesis. Postoperative radiological results showed adequate correction of vertebral alignment and significant clinical improvement in terms of pain and disability. Minor complications, such as intraoperative bleeding due to complex venous anatomy, were manageable and did not compromise the outcome. However, longer follow-up and inclusion of a larger number of cases are necessary to validate long-term results and determine the viability of this technique in a broader population. Sarthak Mohanty 1 , Zeeshan Sardar 1 , Michael Kelly 2 , Josephine Coury 1 , Justin Reyes 1 , Fthimnir Hassan 1 , Nathan Lee 1 , Justin Scheer 1 , Steven Roth 1 , Chun Wai Hung 1 , Joseph Lombardi 1 , Ronald A. Lehman 1 , Lawrence Lenke 1 1 Columbia University Medical Center, New York, United States , 2 Rady Children's Hospital, San Diego, United States Introduction: Investigations in asymptomatic adults revealed harmonious T4-L1-Hip Axis, characterized by T4 pelvic angle(T4PA) within 4° of L1PA. Understanding the impact of L1PA/T4PA malalignment on MC and PROs is critical. Methods: T4PA-L1PA mismatch was assessed at 6 weeks postop following deformity correction and patients were followed for 2Y thereafter. Key outcomes were MC, encompassing implant-related reoperations and reoperations for PJK/F alongside attainment of MCID for SRS and ODI PROs at 2Y postop. MCID thresholds were 0.4 for SRS scores and -11 for ODI. A multivariable logistic regression model investigated the association between (T4PA-L1PA) 2 and MC, adjusting for comorbidities (CCI), preop alignment, UIV, pelvic fixation, and the correction magnitude. A polynomial logistic regression was employed to model the quadratic relationship between T4PA-L1PA and MC risk, with plots illustrating the probability of MC across the T4PA-L1PA spectrum. Logistic regression analyses investigated the relationship between (T4PA-L1PA) 2 mismatch and MCID in PROs. Results: 427 patients with mean age 61.2 (± 0.7), 12.50 (± 0.2) instrumented levels, and 78.7% undergoing pelvic fixation were included. 66 (15.5%) patients underwent MC-related reoperations. Univariate analysis revealed higher CCI (OR = 1.3, p = 0.001), increased (T4PA-L1PA) 2 (OR = 1.01, p < 0.001), lower preop TK (OR = 0.99, p = 0.021), increased ΔPI-LL (OR = 1.01, p = 0.037), and ΔT4PA (OR = 1.03, p = 0.029) were associated with higher odds of MC. In the multivariable model (AUC = 0.72, p < 0.001), higher CCI (OR = 1.21, p = 0.029), pelvic fixation (OR = 2.78, p = 0.022), and greater (T4PA-L1PA) 2 (OR = 1.01, p < 0.001) were independent predictors of MC. The probability of MC across T4PA-L1PA values indicated that both over- and under-correction are associated with MC. (T4PA-L1PA) 2 was not associated with achieving MCID in SRS activity (p = 0.635), pain (p = 0.444), appearance (p = 0.800), mental health (p = 0.800), satisfaction (p = 0.189), and ODI (p = 0.472). Conclusions: Aligning T4-L1PA mismatch within normative ranges mitigates mechanical complications but does not significantly influence attainment of MCID. This suggests that mechanical complications are driven by alignment, while PROs are influenced by biopsychosocial factors. François Dantas 1 , Fatemeh Alavi 2 , Stephen Lewis 3 , Christopher J. Nielsen 3 , Raja Rampersaud 3 1 Toronto Western Hospital, Neurosurgery, Toronto, Canada , 2 University Health Network, Osteoporosis Program, Schroeder's Arthritis Institute, Toronto, Canada , 3 Toronto Western Hospital, Orthopedic Surgery, Toronto, Canada Introduction: Proximal junctional kyphosis (PJK) and failure (PJF) are recognized as common complications following adult spine deformity (ASD) surgery. Several risk factors are reported including surgical, radiographic, and patient-related factors. The multifactorial etiology of PJK and the presence of controversial risk factors highlight the necessity for ongoing research in this area. We hypothesized that commonly assessed sagittal spinopelvic parameters, along with specific geometrically defined variables derived from immediate postoperative radiographs, could clarify alignment-related risk factors for PJK. This study aimed to introduce new geometrically relevant sagittal parameters associated with PJK. Material and Methods: 91 ASD patients who underwent corrective spinal fusion from the lower thoracic spine to the pelvis were included in this single institution study. The minimum follow-up was 1 year. PJK was defined as more than 10 degrees post-to-preoperative changes in the angle between the upper endplate of the upper-instrumented vertebra (UIV) and two levels above (UIV+2). A framework was developed to automatically extract 56 sagittal alignment parameters from immediate postoperative radiographs. Among them, we defined two triangles including the femoral head (FH): fused triangle (FH_UIV_S1) and unfused triangle (FH_UIV_T1). Three geometrical parameters were defined: Gamma angle, defined as an angle between the lines connecting UIV to T1 and UIV to FH, as well as T1FH_distance, defined as the distance of UIV to a line connecting T1 to FH in the non-fused triangle. Beta angle was defined as an angle between the lines connecting UIV to FH and UIV to S1 in the fused triangle. Two-sided independent t-test was performed to determine the significant factors between PJK and non-PJK groups. Results: 42 out of 91 patients developed PJK (46%). There was no difference in sex, age, pelvic incident (PI), pelvic tilt (PT), and regional parameters such as L4_S1, L1_S1, and L1_L4 between PJK and non-PJK groups. However, 14 postoperative sagittal parameters with significant differences between the two groups were identified. Other than sagittal vertical angle (SVA), global tilt (GT), and TPA_IPPA mismatch, UIV contributed to all other 11 parameters including C2_UIV_PA, T1_UIV-pA, C2PA, TPA, UIV_L1_Cobb angle, UIV_IP_Cobb angle, UIVPA_L1PA mismatch, UIVPA_IPPA mismatch, UIV angle, Gamma, and distance to the T1_FH line. Non-PJK patients had more posteriorly inclined UIV than PJK patients (5.5 o vs. 1 o ; p-value < 0.001). Gamma angle was larger in the non-PJK group compared to the PJK group (154 o vs. 148 o ; p-value 0.001). Conclusion: The position of UIV following low thoracic to pelvis instrumented fusion influences the UIV inclination, Gamma angle, and distance of UIV to T1_FH line, which are important sagittal alignment variables in the geometric assessment of risk factors for PJK. Further research utilizing these methods is warranted given the association of the UIV in all but three parameters. Christopher J. Nielsen 1 , François Dantas 2 , Fatemeh Alavi 3 , Stephen Lewis 1 , Raja Rampersaud 1 1 Toronto Western Hospital, Orthopedic Surgery, Toronto, Canada , 2 Toronto Western Hospital, Neurosurgery, Toronto, Canada , 3 University Health Network, Toronto, Canada Introduction: Upper thoracic reciprocal change is a common compensatory mechanism following corrective fusion surgery. The upper thoracic compensatory mechanism remains poorly predictable. We hypothesized that postoperative upper thoracic parameters can be predicted by a combination of preoperative and surgical planning parameters. Thoracic kyphosis (TK) was defined as T1_UIV_Cobb angle. This study aimed to determine postoperative TK based on the preoperative and surgical planning variables in ASD patients using a machine-learning (ML) algorithm. Material and Methods: A consecutive series of patients (mean age 66.7 ± 10.8 years, 65.9% females) with ASD underwent corrective spinal fusion from the lower thoracic spine (T9-T12) to the pelvis in a single institution from 2010-2023. The preoperative and immediate postoperative radiographs were used to measure spinopelvic parameters. A predictive model using linear regression was built for postoperative PT from 91 patients (80% training, 20% validation). All extracted preoperative spinopelvic parameters and surgical parameters, such as upper-instrumented vertebra pelvic angle (UIVPA) and its distance to the sacrum, were included to build a PT predictive model. To validate the ML model, the postoperative pelvic tilt was compared with the predicted values. Results: We found that postoperative thoracic kyphosis is significantly correlated with age, four preoperative parameters, and postoperative UIVPA as a surgical planning parameter. The preoperative predictors are thoracic kyphosis, global tilt (GT), UIV tilt, and the distance of UIV to a line connecting T1 to the femoral head (FH). The ML-based model with R 2 = 0.76 indicates a good correlation between predictors and postoperative TK. The mean absolute error was 5° for training and validation groups, which is within the range of measurement error. Conclusion: ML algorithm can predict postoperative compensation in the non-fused thoracic spine for patients with lower thoracic fusion to the pelvis. Leveraging this technology can be helpful for preplanning alignment to determine postoperative UIVPA and may reduce the risk of mechanical complications. This algorithm can predict changes in thoracic kyphosis in the non-instrumented spine. Important parameters based on this algorithm include patient age and global sagittal parameters, such as global tilt and UIVPA. Tomohisa Harada 1,2 1 Sangubashi Spine Surgery Hospital, Tokyo, Japan , 2 Rakuwakai Marutamachi Hospital, Spine Center, Kyoto, Japan Introduction: The purpose of this study was to investigate whether cMIS using LIF and All PPS is useful for severe ASD. Material and Methods: The subjects were 78 consecutive ASD patients (5 males and 73 females) who underwent cMIS using LIF and All PPS by a single surgeon at a single institution from October 2013 to July 2023 with at least 1 year of follow-up. The mean age at surgery for all patients was 72 years (50-84 years), and patients with bony fusion between multiple vertebrae were excluded. The range of fixation was from the lower thoracic spine to the pelvis in all cases, and the number of fixed levels was 8 in 72 cases and 9 in 6 cases. Patients with a preoperative Cobb angle or pelvic incidence (PI)-lumbar lordosis (LL) mismatch of 50 degrees or greater were classified into the severe group (S group), and those with both parameters less than 50 degrees were classified into the moderate group (M group). Preoperative and postoperative radiographic parameters (coronal Cobb angle, LL angle, PI-LL mismatch, sagittal vertical axis (SVA), operative time, intraoperative blood loss, and complications were retrospectively evaluated. Results: There were 51 patients in the S group (4 males and 47 females) and 27 patients in the M group (1 male and 26 females), with a mean age of 73 and 71 years, respectively. In the S group, the mean Cobb angle was corrected from 54 to 16 degrees, the mean LL from 4 to 50 degrees, the mean PI-LL mismatch from 48 to 0 degrees, SVA from 153 to 9 mm, and PT from 36 to 18 degrees. In the M group, the mean Cobb angle was corrected from 35 to 9 degrees, mean LL from 20 to 51 degrees, mean PI-LL mismatch from 32 to -1 degree, SVA from 84 to -5 mm, and PT from 31 to 19 degrees. Mean operative time was 378 and 346 minutes for the S and M groups, and intraoperative blood loss was 435 and 351 ml, respectively. Postoperative complications included muscle weakness and sensory disturbance of the lower extremities in 15 patients (29%) in the S group and 7 patients (about 26%) in the M group, of whom 4 patients in the S group had mild numbness and 3 patients had residual muscle weakness at the MMT3 level. Rod breakage was observed in 13 (25%) and 9 (33%) patients, respectively; PJK was observed in 3 patients in the S group and 2 patients in the M group, and 2 patients in the S group underwent revision surgery. There were also cases of postoperative iatrogenic disc herniation and intradural hematoma requiring reoperation in the S group, as well as case of intercostal artery hemorrhage requiring embolization. Conclusion: We believe that cMIS using LIF and PPS for ASD is a minimally invasive and useful technique that provides ideal correction. However, postoperative complications are frequent in patients with severely deformity, and Attention should be paid.