Disc Degeneration in Distal Unfused Segments: Cause or Consequence of Adding-On After Posterior Fusion of Lenke 3c, 5c, 6c Adolescent Idiopathic Scoliosis?

Disc Degeneration in Distal Unfused Segments: Cause or Consequence of Adding-On After Posterior Fusion of Lenke 3c, 5c, 6c Adolescent Idiopathic Scoliosis? | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Disc Degeneration in Distal Unfused Segments: Cause or Consequence of Adding-On After Posterior Fusion of Lenke 3c, 5c, 6c Adolescent Idiopathic Scoliosis? Hakan Serhat Yanik, Mert Kahraman Marasli, Ismail Emre Ketenci, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5112797/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Jan, 2025 Read the published version in Acta Neurochirurgica → Version 1 posted 9 You are reading this latest preprint version Abstract Background The aim of this study is to examine the association between adding-on (AO) and disc degeneration(DD) of distal unfused levels in Lenke 3C, 5C, 6C adolescent idiopathic scoliosis (AIS) patients with a follow-up of at least two years by comparing preoperative and postoperative magnetic resonance imaging (MRI). Methods 47 AIS patients (32 females and 15 males) with structural thoracolumbar/lumbar (TL/L) curves treated with long segment thoracolumbar fusion were retrospectively evaluated. Patients were divided into two groups according to the occurrence of the AO (AO and Non-AO groups). The unfused discs were graded using the MRI images according to the Pfirrmann grading method. The Scoliosis Research Society-22 (SRS-22) questionnaire and Visuel Analog Scale (VAS) were used to determine clinical outcomes. Results The frequency of AO was found to be 29.78%. Preoperative MT curve and TL/L curve angles; LIV translation, LIV disc angle, LIV +1 translation at final follow-up and the number of fused levels were significantly higher in the AO group. Postoperative total Pfirrmann Score was significantly associated with AO. L5-S1 disc in the AO group had a statistically significant higher Pfirrmann grade than the Non-AO group. No significant association was found between the VAS and SRS-22 scores related to AO, DD or other radiological outcomes. Conclusion Although the AO was detected at a high rate in Lenke 3C, 5C, 6C AIS patients and its association with DD in distal unfused levels was demonstrated, no impact on clinical scores was found. Furthermore, patients with AO developed significantly higher DD in L5-S1 disc, even if it is not the segment adjacent to the fusion. Even if this DD does not cause complaints in the young AIS population, L5-S1 disc should be evaluated in patients with AO, since it may cause complaints in longer follow-up. adding-on degeneration disc adolescent idiopathic scoliosis Type of study/level of evidence: Therapeutic IV Figures Figure 1 INTRODUCTION Adolescent idiopathic scoliosis (AIS) can be described as a complex 3D spinal deformity which affects 2–3% of the global population[ 13 ]. In AIS, a post-operative phenomenon known as "distal add-on" (AO) is characterised by a failure of progressive correction due to an accumulation of either lumbar vertebral deviation or disc angulation below the instrumentation. The frequency of AO in AIS patients after corrective surgery has been widely researched and documented, with findings varying widely from 0.8–51.1%[ 10 , 16 ]. This variability has led to controversy in the field[ 17 ]. As a potential postoperative complication that might result in poor radiologic and clinical outcomes, the AO has become more prevalent in recent years. To date, there have been few studies examining the progression of disc degeneration(DD) in distal, unfused spinal segments in AIS[ 3 , 6 , 4 ]. Previous research has suggested that spinal fusion in AIS may result in greater lever arm and movement at unfused vertebral levels, potentially accelerating DD. This phenomenon, also termed "asymmetric loading combined with degeneration," may contribute to an adverse cycle of accelerated curve expansion[ 8 ]. Nevertheless, the relationship between AO and DD in distal unfused levels has not yet been adequately elucidated. Present study addresses two key questions. Firstly, it examines the role of preoperative disc status in the development of AO. Secondly, it assesses whether discs in the distal unfused segments are more susceptible to deterioration in patients who develop AO. Additionally, it identifies the specific disc characteristics that are associated with AO and determines which disc should be the primary focus of monitoring due to the established clinical implications of disc degeneration, even in the absence of symptoms in younger AIS patients. The objective of this study was to investigate the relationship between AO and DD of distal unfused levels in AIS patients with a minimum two-year follow-up period, by comparing preoperative and postoperative MRI scans. The hypothesis put forth is that AO may be a causal factor in, and/or a catalyst for, accelerated DD. MATERIAL AND METHODS The research was approved by the Institutional Ethics Committee for Clinical Research (No. HNEAH-KAEK 2022/KK/220, Istanbul, Turkey). The subject of the study was 47 patients with AIS, 32 of whom were female and 15 of whom were male. The patients were treated at a single institution, the results of which were evaluated retrospectively. The average follow-up period was 29.14±3.27 months. Inclusion criteria included being under 18 years of age at time of surgery, having a Lenke 3C, 5C or 6C AIS diagnosis, and having at least two years of visit. Patients were also required to have both full-length standing spinal radiographs and T2-weighted magnetic resonance images of the lumbar spine. Patients were excluded if they had congenital scoliosis, a history of lumbar disc herniation or spondylolysis, surgery prior to AIS surgery, subsequent surgery, neurological disease, or malignant spinal disease. Patients lost to follow-up were excluded. Eighteen patients were classified as type 3C, 16 as type 5C and 13 as type 6C according to the Lenke classification. Surgical Technique The senior author performed all operations using the same approach and technique. Following segmental pedicle screw instrumentation (TSI (Tasarımmed Spinal Implants), Tasarımmed, Turkey), the deformity was corrected using rod derotation, distraction, compression, and in situ bending maneuvers. The types, configurations, extents, and rigidities of the deformity were taken into consideration when determining the optimal instrumentation levels. In order to determine the LIV, the stable, last touch, neutral, and end vertebrae were taken into consideration. LIV was determined to be L3 in 24 patients and L4 in 23 patients. Patients were divided into two groups based on the presence of AO: AO group and non-AO group. Radiographic and Clinical Outcome Measurements All patients underwent a comprehensive evaluation of their radiological data, which included the analysis of standing anterior-posterior and lateral radiographs, as well as MRI scans. The radiological parameters were measured on plain radiographs taken prior to surgery, at one week postoperatively, and at the final follow-up. The results are as follows: The Cobb angles of the MT and TL/L curves and the LIV translation, LIV+1 translation and LIV disc angle (LIVDA) were also assessed. LIV translation (and similarly LIV+1 translation) was defined as the distance in millimetres between the middle of the LIV (and LIV+1) and the central sacral vertical line (CSVL). LIVDA was defined as the angulation of the first disc below the LIV. AO was defined as a progression in the number of distal vertebrae included in the main curve, in combination with a deviation of more than 5 mm from the CSVL or an increase of more than 5° in LIVDA, as described[16]. The discs were evaluated via sagittal T2-weighted images, according to a five-grade scale, which illustrates process from normal disc to severe DD. This was done using the Pfirrmann grading method, with grade I corresponding to no degeneration and grade V indicating the most severe degeneration[12]. In accordance with the literature, Pfirrmann scores were obtained as the mean of the Pfirrmann scores for all unfused discs below LIV[2]. Scoliosis Research Society-22 (SRS-22) and Visual Analogue Scale (VAS) scores were used to assess clinical outcomes. Statistical analysis All clinical, demographic, and radiological parameters were subjected to statistical analysis. For categorical variables, the chi-square test was employed, while for continuous data, the independent t-test was used to assess the statistical significance of the relationship. Correlation analysis was conducted using both Pearson and Spearman correlation tests. RESULTS The average age of the patients was 14.55 ± 2.59 years. The prevalence of AO was 29.78%. Table 1 shows the demographic characteristics of the subjects. Preoperative thoracic and lumbar curves were significantly superior in the AO group compared to the non-AO group (Table 2 ). As expected, LIV translation, LIV + 1 translation and LIVDA were significantly increased in the AO group (Table 3 ). While there was a significant elevation of LIV translation in the AO group at final visit, there was a significant decrease in the non-AO group. Pfirrmann grade and L5-S1 disc score were significantly higher in the AO group (Table 4 ). Although Pfirrmann score was higher in LIV4 (3.13 ± 0.50) than in LIV3 (2.83 ± 0.53), this difference did not reach statistical significance (p = 0.051). Table 1 Demographic characteristic of subjects. Characteristics AO group (n = 14) No AO group(n = 33) p value Age 14.75 ± 2.38 14.07 ± 3.07 0.172 Gender (Male/Female) 4/10 11/22 0.749 BMI 21.50 ± 3.25 20.24 ± 3.00 0.146 Follow-up (months) 29.5 ± 3.71 29 ± 3.12 0.715 Risser grade 1.71 ± 1.43 2.60 ± 1.63 0.082 Number of fused levels 14.64 ± 0.49 13.45 ± 2.12 0.006* BMI indicates Body Mass Index; * statistically significant Table 2 Preoperative and postoperative deformity values. Radiographic Parameters AO group (n = 14) No AO group(n = 33) p value Thoracic Curve (º) Preoperative 47.56 ± 15.96 37.96 ± 15.45 0.041* Postoperative 11.32 ± 5.44 9.72 ± 5.27 0.352 Correction Rate (%) 75.02 ± 11.85 71.97 ± 17.95 0.871 Lumbar Curve (º) Preoperative 54.87 ± 14.47 39.36 ± 12.35 < 0.001* Postoperative 13.05 ± 4.00 11.12 ± 4.94 0.204 Correction Rate (%) 75.34 ± 8.58 68.67 ± 15.10 0.079 *indicates statistically significant Table 3 Comparison of early postoperative and final follow-up radiographic outcomes of LIV related parameters. Parameters AO group (n = 14) No AO group(n = 33) p value LIV-EV 0.35 ± 0.49 0.24 ± 0.43 0.426 LIV-SV -1.35 ± 0.49 -1.18 ± 0.39 0.199 LIV (number of patients) L3 5 19 0.170 L4 9 14 LIV Translation (mm) Early Postoperative 10.48 ± 6.93 11.08 ± 6.95 0.789 Final follow-up 16.02 ± 4.90 8.92 ± 6.37 < 0.001* p’ value 0.019 * 0.036* LIV + 1 Translation (mm) Early Postoperative 7.3 ± 4.33 6.87 ± 5.54 0.538 Final follow-up 8.95 ± 3.86 5.68 ± 4.02 0.006* p’ value 0.245 0.073 LIVDA Early Postoperative 3.26 ± 2.33 3.04 ± 2.26 0.935 Final follow-up 7.31 ± 3.63 3.18 ± 2.49 < 0.001* p’ value 0.001 * 0.537 LIV-EV indicates lowest instrumented vertebra- end vertebra; LIV-SV, lowest instrumented vertebra- stabile vertebra; LIVDA, LIV disc angle; *statistically significant p value means difference between AO and Non-AO group. p’ value means difference between early postoperative and final follow-up. Table 4 Preoperative and final follow-up assessment of Pfirrmann's grading of disk degeneration. Pfirrmann Disc Grade AO group (n = 14) No AO group(n = 33) p value L3-L4 preoperative 2.16 ± 0.40 2.29 ± 0.46 0.4562 L3-L4 postoperative 2.5 ± 0.54 2.52 ± 0.62 0.920 p’ value 0.157 0.157 L4-L5 preoperative 2.42 ± 0.51 2.57 ± 0.70 0.636 L4-L5 postoperative 3 ± 0.55 2.66 ± 0.69 0.060 p’ value 0.011* 0.366 L5-S1 preoperative 3.14 ± 0.66 2.93 ± 0.74 0.377 L5-S1 postoperative 3.78 ± 0.69 3.18 ± 0.68 0.007* p’ value 0.021* 0.046* Pfirrmann Score preoperative 2.71 ± 0.47 2.67 ± 0.50 0.758 Pfirrmann Score postoperative 3.28 ± 0.54 2.85 ± 0.47 0.011* *indicates statistically significant. p value means difference between AO and Non-AO group. p’ value means difference between preoperative and postoperative. No significant associations were obtained between the VAS, SRS-22 total score and AO subscores (Table 5 ). No cases of implant failure or the need for a second surgical procedure were observed in any patient at follow-up. Table 5 Comprehensive Clinical Outcomes. Clinical Outcomes AO group (n = 14) No AO group(n = 33) p value SRS-22 (Postoperative) Pain 4.17 ± 1.36 4.34 ± 1.00 0.631 Function 4.40 ± 0.74 4.64 ± 0.57 0.214 Mental Health 4.36 ± 0.78 4.59 ± 0.65 0.206 Self Image 4.52 ± 0.75 4.59 ± 0.55 0.771 Satisfaction 4.59 ± 0.61 4.80 ± 0.39 0.205 Total 4.41 ± 0.66 4.67 ± 0.45 0.108 VAS Preoperative 5.71 ± 2.43 4.63 ± 2.89 0.206 Postoperative 1.64 ± 1.21 2 ± 2.17 0.806 SRS indicates Scoliosis Research Society; VAS, visual analog scale DISCUSSION Long fusion represents an accepted treatment method for Lenke 3C and 6C AIS, while it is an option in the treatment of Lenke 5C AIS[ 15 , 9 ]. In the case of Lenke 5C AIS, long fusion is performed in lieu of selective lumbar fusion in order to prevent the loss of TC correction. LIV is typically selected as LEV in patients with structural TL/L curves, which primarily correspond to L3 or L4[ 14 ]. AO may occur in any case, as short fusions may result in postoperative decompensation due to curve progression, while long fusions may reduce the likelihood of compensation. It is therefore evident that the selection of the patient population is of paramount importance in determining the frequency of AO. The aim of this study was to evaluate Lenke 3C, 5C and 6C patients with LIV as L3 or L4 in order to construct a more homogeneous group. The frequency of AO was found to be 29.78% in this study. In a similar group of patients, Koller et al.[ 7 ] found the frequency of AO to be 34%. Several risk factors have been identified for AO, including younger age, lower Risser grade and overcorrection of the deformity[ 17 ]. However, this study obtained no differences between groups in terms of these parameters. The selection of LIV is also of great importance in order to prevent AO. Yang et al. identified that LIV-stable vertebra (SV) ≤ -2 and LIV-end vertebra (EV) ≤ 1 were associated with an elevated risk of AO. Our LIV-SV and LIV-EV values were comparable between groups (Table 3 ). These findings indicate that AO is a multifactorial complication. A number of studies have evaluated the occurrence of DD after AIS surgery and a variety of risk factors have been established. It has been demonstrated that coronal alignment affects the development of DD. Yeung et al. [ 18 ]demonstrated that in patients with severe AIS, there was a significant reduction in disc volume and nucleus pulposus, accompanied by coronal wedging of the vertebral body and intervertebral disc. Akazawa et al.[ 1 ] observed that patients with DD exhibited a significantly greater lumbar curve at the final assessment, and that there was a positive correlation between the L3-4 wedge angle and L3-4 Pfirrmann disc grade two years after surgery. The reason for this could be that there are histological abnormalities in scoliotic intervertebral discs which result in a wedge-shaped configuration with segments that are both concave and convex, and which are subjected to differential mechanical stress[ 5 ]. It seems reasonable to suggest that minimising lumbar curvatures in AIS surgery may help to reduce DD[ 1 ]. However, could this paradoxically increase the risk of DD due to fewer mobile segments and increased fusion mass? As expected, the LIV translation, LIV + 1 translation and LIVDA were markedly elevated in the AO group. Additionally, the number of fused levels was higher, and DD was observed in a greater number of segments in the AO group. The results of recent studies suggest that in addition to adjacent segments, all segments below the fusion site should be evaluated for DD during the period of follow-up. A study by Lonner et al. found that more than half of the cases of DD involved the second disc (35.5%) and third disc (20%) caudal to the LIV. The LIV of L4 was found to have the largest risk of presenting with significant DD compared to more cephalad LIVs. Although the association with AO was not investigated, the study demonstrated an association between coronal balance and DD, such as wedging of the disc adjacent to the LIV (≥ 5°) and LIV translation (≥ 2 cm), which resulted in a sixfold increase in DD[ 11 ]. In our study, the Pfirrmann score was greater in patients with LIV at L4 than in patients with L3, but the difference was not statistically significant. Green et al. performed both preoperative and postoperative MRI in 20 patients with a average follow-up of 11.8 years and showed that new disc pathology was identified in the distal unfused segments in 85% of patients, with the majority of DD occurring at L5/S1[ 5 ]. In the current study, we observed that the discs of L4-L5 and L5-S1 showed a statistically significant increase in Pfirrmann grade at the postoperative follow-up compared to the preoperative stage in the AO group. In the non-AO group, the only case of worsening was observed in the L5-S1 disc. It would be beneficial to consider the following questions: Does AO correlate with an increase in DD? It would be of interest to ascertain whether DD increases the frequency of AO. The findings of this study indicate that there is no association between preoperative Pfirrmann disc grade below the fusion or preoperative total Pfirrmann score and AO. However, the postoperative total Pfirrmann score was found to be significantly associated with AO. The objective of this study is to examine potential correlations rather than to ascertain a definitive cause-and-effect relationship. Nevertheless, it is challenging to ascertain which parameters are more determinative, given that the question of whether AO will develop or not is multifactorial. However, an examination of the subsequent circumstances with regard to the correlation between AO and DD revealed a statistically significant increase in Pfirrmann grade for the L5-S1 disc in the AO group compared to the Non-AO group postoperatively. This recent finding is of considerable interest. The appearance of the iliolumbar and lumbosacral ligaments, coronally oriented facets and laminae, a wedge-shaped disc, and their junctional placement make the L5-S1 level distinctive among the lower lumbar levels. Sabnis et al[ 14 ] showed that the L5-S1 mobile segment has distinct degenerative and kinematical characteristics related to DD and facet joint osteoarthritis compared to the upper lumbar mobile segments, which develop independently but not at the other lumbar levels. In our study, the L5-S1 disc degenerated postoperatively in both groups. It can be concluded that the L5-S1 disc, which is already susceptible to degeneration, is further compromised in the presence of AO. A limited sample size and a relatively short follow-up period are limitations of the study. In addition, the study lacked a control group that would have allowed evaluation of the natural history of lumbar discs in healthy subjects or in untreated AIS patients. The main strengths of the study are the consistency of the surgical technique and the homogeneity of the patient groups, as well as the availability of preoperative and postoperative magnetic resonance (MR) imaging. In conclusion, despite the absence of a direct comparison, patients with AO exhibited a significantly higher degree of DD at the L5-S1 level, although this was not the segment adjacent to the fusion. The distinctive kinematic and structural characteristics of the L5-S1 disc may be the underlying cause of this degeneration. In instances where AO develops, the primary consideration is the patient's presentation. In the absence of patient-reported symptoms and excessive curve progression, a conservative follow-up approach is the most appropriate course of action. The findings of our study indicated that there was no statistically significant difference in clinical scores between the group with AO and the group without AO. This prompts the question of what should be taken into careful consideration in patients who develop AO and are followed up. Despite the absence of significant differences in clinical outcomes between the AO and non-AO groups, we advise that patients with AO should undergo examination of the L5-S1 disc, as this may result in complications over time. Declarations no declaration. Conflict of interest : No conflict of interest. Funding : No funding. Ethical approval : Approved by Haydarpasa Numune Training and Research Hospital Editorial Board with 2022/KK/220 number. Availability of data and materials: Data is available and can be sent upon request. Acknowledgements : No acknowledgements Authors’ contribution : All of authors meet conditions 1, 2, 3 and 4.1) made substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data; or the creation of new software used in the work; 2) drafted the work or revised it critically for important intellectual content; 3) approved the version to be published; and 4) agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. 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Cite Share Download PDF Status: Published Journal Publication published 02 Jan, 2025 Read the published version in Acta Neurochirurgica → Version 1 posted Editorial decision: Revision requested 10 Oct, 2024 Reviews received at journal 08 Oct, 2024 Reviews received at journal 24 Sep, 2024 Reviewers agreed at journal 24 Sep, 2024 Reviewers agreed at journal 24 Sep, 2024 Reviewers invited by journal 22 Sep, 2024 Editor assigned by journal 20 Sep, 2024 Submission checks completed at journal 20 Sep, 2024 First submitted to journal 18 Sep, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5112797","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":364560573,"identity":"48c78214-5b9c-4a07-bf51-75232567eb4a","order_by":0,"name":"Hakan Serhat Yanik","email":"","orcid":"","institution":"Haydarpaşa Numune Eğitim ve Araştırma Hastanesi","correspondingAuthor":false,"prefix":"","firstName":"Hakan","middleName":"Serhat","lastName":"Yanik","suffix":""},{"id":364560574,"identity":"88bb700f-87d5-42f0-acd3-aee8b51a1e0b","order_by":1,"name":"Mert Kahraman Marasli","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+UlEQVRIiWNgGAWjYFADdsYGBgY2GyCLsfEAAbUgpUDADNaSBhYgVguIYDsMZuPVotve+/zRjZp78vLNzA1MN8rO261tPwy0pcYmGpcWszPHDZtzjhUbbjjM2MCcc+528rYziUAtx9JyG3BpuZHG2JzDlsC4AegX5ty228lmB4BaGBsO49Zy/xlQy78E+/nNYC3nks3OPySg5QYbY3NuW0Jiw2GwlgN2ZjcI2XImjXF2bl9CMsgvh3POJSeY3QDakoDPL8ePMXzO+ZZgO7+9/eHjnDI7e7Pz6Q8ffKixwakFBRwA4kSwygRilMOAPSmKR8EoGAWjYGQAANhbZh6A6II6AAAAAElFTkSuQmCC","orcid":"","institution":"Haydarpaşa Numune Eğitim ve Araştırma Hastanesi","correspondingAuthor":true,"prefix":"","firstName":"Mert","middleName":"Kahraman","lastName":"Marasli","suffix":""},{"id":364560575,"identity":"246ac08f-a7f4-48f4-93e6-e6fe238f54ec","order_by":2,"name":"Ismail Emre Ketenci","email":"","orcid":"","institution":"Haydarpaşa Numune Eğitim ve Araştırma Hastanesi","correspondingAuthor":false,"prefix":"","firstName":"Ismail","middleName":"Emre","lastName":"Ketenci","suffix":""},{"id":364560576,"identity":"06abf719-7476-42f8-840e-d39918c7fd08","order_by":3,"name":"Şevki Erdem","email":"","orcid":"","institution":"Haydarpaşa Numune Eğitim ve Araştırma Hastanesi","correspondingAuthor":false,"prefix":"","firstName":"Şevki","middleName":"","lastName":"Erdem","suffix":""}],"badges":[],"createdAt":"2024-09-18 23:59:33","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5112797/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5112797/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00701-024-06412-4","type":"published","date":"2025-01-02T15:57:45+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":71869229,"identity":"67492d2c-4ecc-4d0a-b065-fe8144663f2d","added_by":"auto","created_at":"2024-12-19 10:04:12","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":7748575,"visible":true,"origin":"","legend":"\u003cp\u003eFigure A, B and C illustrate anteroposterior (AP) bending radiographs of a 15-year-old male patient with Lenke 3C AIS, taken from the right and left sides, respectively.\u003c/p\u003e\n\u003cp\u003eD: The preoperative T2 sagittal magnetic resonance imaging (MRI) image demonstrates Pfirmann grade 2 degeneration at the L4-5 disc and grade 3 at the L5-S1 disc.\u003c/p\u003e\n\u003cp\u003eE: An anteroposterior radiograph taken one week after surgery demonstrates that the lumbar deformity has been corrected and that the lumbar intervertebral disc is at the L4 level.\u003c/p\u003e\n\u003cp\u003eF: The final postoperative AP radiograph, taken two years after surgery, demonstrates an increased LIVDA, as well as a distal adding-on phenomenon.\u003c/p\u003e\n\u003cp\u003eG: Final postoperative coronal computed tomography (CT) image.\u003c/p\u003e\n\u003cp\u003eH: The final postoperative T2 sagittal MRI scan illustrates that grade 3 Pfirmann degeneration is present at the L4-5 disc and that grade 4 is present at the L5-S1 disc.\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-5112797/v1/78ac63387a511684f1c9a40e.png"},{"id":73093382,"identity":"f56d2c64-60e6-418c-8c24-586af9cd6b94","added_by":"auto","created_at":"2025-01-06 16:15:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7666505,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5112797/v1/c147a3ed-9468-47db-8c92-68743ee6ff4c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Disc Degeneration in Distal Unfused Segments: Cause or Consequence of Adding-On After Posterior Fusion of Lenke 3c, 5c, 6c Adolescent Idiopathic Scoliosis?","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eAdolescent idiopathic scoliosis (AIS) can be described as a complex 3D spinal deformity which affects 2\u0026ndash;3% of the global population[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In AIS, a post-operative phenomenon known as \"distal add-on\" (AO) is characterised by a failure of progressive correction due to an accumulation of either lumbar vertebral deviation or disc angulation below the instrumentation. The frequency of AO in AIS patients after corrective surgery has been widely researched and documented, with findings varying widely from 0.8\u0026ndash;51.1%[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. This variability has led to controversy in the field[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. As a potential postoperative complication that might result in poor radiologic and clinical outcomes, the AO has become more prevalent in recent years.\u003c/p\u003e \u003cp\u003eTo date, there have been few studies examining the progression of disc degeneration(DD) in distal, unfused spinal segments in AIS[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Previous research has suggested that spinal fusion in AIS may result in greater lever arm and movement at unfused vertebral levels, potentially accelerating DD. This phenomenon, also termed \"asymmetric loading combined with degeneration,\" may contribute to an adverse cycle of accelerated curve expansion[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Nevertheless, the relationship between AO and DD in distal unfused levels has not yet been adequately elucidated. Present study addresses two key questions. Firstly, it examines the role of preoperative disc status in the development of AO. Secondly, it assesses whether discs in the distal unfused segments are more susceptible to deterioration in patients who develop AO. Additionally, it identifies the specific disc characteristics that are associated with AO and determines which disc should be the primary focus of monitoring due to the established clinical implications of disc degeneration, even in the absence of symptoms in younger AIS patients. The objective of this study was to investigate the relationship between AO and DD of distal unfused levels in AIS patients with a minimum two-year follow-up period, by comparing preoperative and postoperative MRI scans. The hypothesis put forth is that AO may be a causal factor in, and/or a catalyst for, accelerated DD.\u003c/p\u003e"},{"header":"MATERIAL AND METHODS","content":"\u003cp\u003eThe research was approved by the Institutional Ethics Committee for Clinical Research (No. HNEAH-KAEK 2022/KK/220, Istanbul, Turkey). \u0026nbsp;The subject of the study was 47 patients with AIS, 32 of whom were female and 15 of whom were male. The patients were treated at a single institution, the results of which were evaluated retrospectively. The average follow-up period was 29.14±3.27 months. Inclusion criteria included being under 18 years of age at time of surgery, having a Lenke 3C, 5C or 6C AIS diagnosis, and having at least two years of visit. Patients were also required to have both full-length standing spinal radiographs and T2-weighted magnetic resonance images of the lumbar spine. Patients were excluded if they had congenital scoliosis, a history of lumbar disc herniation or spondylolysis, surgery prior to AIS surgery, subsequent surgery, neurological disease, or malignant spinal disease. Patients lost to follow-up were excluded. Eighteen patients were classified as type 3C, 16 as type 5C and 13 as type 6C according to the Lenke classification.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSurgical Technique\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe senior author performed all operations using the same approach and technique. Following segmental pedicle screw instrumentation (TSI (Tasarımmed Spinal Implants), Tasarımmed, Turkey), the deformity was corrected using rod derotation, distraction, compression, and in situ bending maneuvers. The types, configurations, extents, and rigidities of the deformity were taken into consideration when determining the optimal instrumentation levels. In order to determine the LIV, the stable, last touch, neutral, and end vertebrae were taken into consideration. LIV was determined to be L3 in 24 patients and L4 in 23 patients. Patients were divided into two groups based on the presence of AO: AO group and non-AO group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRadiographic and Clinical Outcome Measurements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll patients underwent a comprehensive evaluation of their radiological data, which included the analysis of standing anterior-posterior and lateral radiographs, as well as MRI scans. The radiological parameters were measured on plain radiographs taken prior to surgery, at one week postoperatively, and at the final follow-up. The results are as follows: The Cobb angles of the MT and TL/L curves and the LIV translation, LIV+1 translation and LIV disc angle (LIVDA) were also assessed. LIV translation (and similarly LIV+1 translation) was defined as the distance in millimetres between the middle of the LIV (and LIV+1) and the central sacral vertical line (CSVL). LIVDA was defined as the angulation of the first disc below the LIV. AO was defined as a progression in the number of distal vertebrae included in the main curve, in combination with a deviation of more than 5 mm from the CSVL or an increase of more than 5° in LIVDA, as described[16].\u003c/p\u003e\n\u003cp\u003eThe discs were evaluated via sagittal T2-weighted images, according to a five-grade scale, which illustrates process from normal disc to severe DD. This was done using the Pfirrmann grading method, with grade I corresponding to no degeneration and grade V indicating the most severe degeneration[12]. In accordance with the literature, Pfirrmann scores were obtained as the mean of the Pfirrmann scores for all unfused discs below LIV[2].\u003c/p\u003e\n\u003cp\u003eScoliosis Research Society-22 (SRS-22) and Visual Analogue Scale (VAS) scores were used to assess clinical outcomes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll clinical, demographic, and radiological parameters were subjected to statistical analysis. For categorical variables, the chi-square test was employed, while for continuous data, the independent t-test was used to assess the statistical significance of the relationship. Correlation analysis was conducted using both Pearson and Spearman correlation tests.\u0026nbsp;\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eThe average age of the patients was 14.55\u0026thinsp;\u0026plusmn;\u0026thinsp;2.59 years. The prevalence of AO was 29.78%. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the demographic characteristics of the subjects. Preoperative thoracic and lumbar curves were significantly superior in the AO group compared to the non-AO group (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). As expected, LIV translation, LIV\u0026thinsp;+\u0026thinsp;1 translation and LIVDA were significantly increased in the AO group (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). While there was a significant elevation of LIV translation in the AO group at final visit, there was a significant decrease in the non-AO group. Pfirrmann grade and L5-S1 disc score were significantly higher in the AO group (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Although Pfirrmann score was higher in LIV4 (3.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.50) than in LIV3 (2.83\u0026thinsp;\u0026plusmn;\u0026thinsp;0.53), this difference did not reach statistical significance (p\u0026thinsp;=\u0026thinsp;0.051).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic characteristic of subjects.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharacteristics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAO group (n\u0026thinsp;=\u0026thinsp;14)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo AO group(n\u0026thinsp;=\u0026thinsp;33)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003ep value\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14.75\u0026thinsp;\u0026plusmn;\u0026thinsp;2.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.07\u0026thinsp;\u0026plusmn;\u0026thinsp;3.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.172\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender (Male/Female)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4/10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11/22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.749\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21.50\u0026thinsp;\u0026plusmn;\u0026thinsp;3.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20.24\u0026thinsp;\u0026plusmn;\u0026thinsp;3.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.146\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFollow-up (months)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e29.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29\u0026thinsp;\u0026plusmn;\u0026thinsp;3.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.715\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRisser grade\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.71\u0026thinsp;\u0026plusmn;\u0026thinsp;1.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.082\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of fused levels\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14.64\u0026thinsp;\u0026plusmn;\u0026thinsp;0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.45\u0026thinsp;\u0026plusmn;\u0026thinsp;2.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.006*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eBMI indicates Body Mass Index; * statistically significant\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePreoperative and postoperative deformity values.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRadiographic Parameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAO group (n\u0026thinsp;=\u0026thinsp;14)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo AO group(n\u0026thinsp;=\u0026thinsp;33)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep value\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThoracic Curve (\u0026ordm;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e47.56\u0026thinsp;\u0026plusmn;\u0026thinsp;15.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e37.96\u0026thinsp;\u0026plusmn;\u0026thinsp;15.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.041*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e11.32\u0026thinsp;\u0026plusmn;\u0026thinsp;5.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e9.72\u0026thinsp;\u0026plusmn;\u0026thinsp;5.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.352\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCorrection Rate (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e75.02\u0026thinsp;\u0026plusmn;\u0026thinsp;11.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e71.97\u0026thinsp;\u0026plusmn;\u0026thinsp;17.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.871\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLumbar Curve (\u0026ordm;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e54.87\u0026thinsp;\u0026plusmn;\u0026thinsp;14.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e39.36\u0026thinsp;\u0026plusmn;\u0026thinsp;12.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e13.05\u0026thinsp;\u0026plusmn;\u0026thinsp;4.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e11.12\u0026thinsp;\u0026plusmn;\u0026thinsp;4.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.204\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCorrection Rate (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e75.34\u0026thinsp;\u0026plusmn;\u0026thinsp;8.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e68.67\u0026thinsp;\u0026plusmn;\u0026thinsp;15.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.079\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e*indicates statistically significant\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of early postoperative and final follow-up radiographic outcomes of LIV related parameters.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAO group (n\u0026thinsp;=\u0026thinsp;14)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo AO group(n\u0026thinsp;=\u0026thinsp;33)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep value\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLIV-EV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.24\u0026thinsp;\u0026plusmn;\u0026thinsp;0.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.426\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLIV-SV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-1.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-1.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.199\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLIV (number of patients)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.170\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLIV Translation (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEarly Postoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10.48\u0026thinsp;\u0026plusmn;\u0026thinsp;6.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.08\u0026thinsp;\u0026plusmn;\u0026thinsp;6.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.789\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFinal follow-up\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.02\u0026thinsp;\u0026plusmn;\u0026thinsp;4.90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.92\u0026thinsp;\u0026plusmn;\u0026thinsp;6.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003ep\u0026rsquo; value\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0.019 *\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.036*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLIV\u0026thinsp;+\u0026thinsp;1 Translation (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEarly Postoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.3\u0026thinsp;\u0026plusmn;\u0026thinsp;4.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.87\u0026thinsp;\u0026plusmn;\u0026thinsp;5.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.538\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFinal follow-up\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.95\u0026thinsp;\u0026plusmn;\u0026thinsp;3.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.68\u0026thinsp;\u0026plusmn;\u0026thinsp;4.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.006*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003ep\u0026rsquo; value\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.245\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.073\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLIVDA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEarly Postoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.26\u0026thinsp;\u0026plusmn;\u0026thinsp;2.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.04\u0026thinsp;\u0026plusmn;\u0026thinsp;2.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.935\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFinal follow-up\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.31\u0026thinsp;\u0026plusmn;\u0026thinsp;3.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.18\u0026thinsp;\u0026plusmn;\u0026thinsp;2.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003ep\u0026rsquo; value\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0.001 *\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.537\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eLIV-EV indicates lowest instrumented vertebra- end vertebra; LIV-SV, lowest instrumented vertebra- stabile vertebra; LIVDA, LIV disc angle; *statistically significant\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003ep value\u003c/em\u003e means difference between AO and Non-AO group.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003ep\u0026rsquo; value\u003c/em\u003e means difference between early postoperative and final follow-up.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePreoperative and final follow-up assessment of Pfirrmann's grading of disk degeneration.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePfirrmann Disc Grade\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAO group (n\u0026thinsp;=\u0026thinsp;14)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo AO group(n\u0026thinsp;=\u0026thinsp;33)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003ep value\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eL3-L4\u003c/p\u003e \u003cp\u003epreoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.29\u0026thinsp;\u0026plusmn;\u0026thinsp;0.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.4562\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eL3-L4\u003c/p\u003e \u003cp\u003epostoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.52\u0026thinsp;\u0026plusmn;\u0026thinsp;0.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.920\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003ep\u0026rsquo; value\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.157\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.157\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eL4-L5\u003c/p\u003e \u003cp\u003epreoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.57\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.636\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eL4-L5\u003c/p\u003e \u003cp\u003epostoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.66\u0026thinsp;\u0026plusmn;\u0026thinsp;0.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.060\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003ep\u0026rsquo; value\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0.011*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.366\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eL5-S1\u003c/p\u003e \u003cp\u003epreoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.14\u0026thinsp;\u0026plusmn;\u0026thinsp;0.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.377\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eL5-S1\u003c/p\u003e \u003cp\u003epostoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.78\u0026thinsp;\u0026plusmn;\u0026thinsp;0.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.007*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003ep\u0026rsquo; value\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0.021*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0.046*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePfirrmann Score\u003c/p\u003e \u003cp\u003epreoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.71\u0026thinsp;\u0026plusmn;\u0026thinsp;0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.67\u0026thinsp;\u0026plusmn;\u0026thinsp;0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.758\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePfirrmann Score\u003c/p\u003e \u003cp\u003epostoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.28\u0026thinsp;\u0026plusmn;\u0026thinsp;0.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.011*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e*indicates statistically significant.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003ep value\u003c/em\u003e means difference between AO and Non-AO group.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003ep\u0026rsquo; value\u003c/em\u003e means difference between preoperative and postoperative.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eNo significant associations were obtained between the VAS, SRS-22 total score and AO subscores (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). No cases of implant failure or the need for a second surgical procedure were observed in any patient at follow-up.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComprehensive Clinical Outcomes.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClinical Outcomes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAO group (n\u0026thinsp;=\u0026thinsp;14)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo AO group(n\u0026thinsp;=\u0026thinsp;33)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep value\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSRS-22 (Postoperative)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e4.17\u0026thinsp;\u0026plusmn;\u0026thinsp;1.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.34\u0026thinsp;\u0026plusmn;\u0026thinsp;1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.631\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFunction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e4.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.64\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.214\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMental Health\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e4.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.59\u0026thinsp;\u0026plusmn;\u0026thinsp;0.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.206\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSelf Image\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e4.52\u0026thinsp;\u0026plusmn;\u0026thinsp;0.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.59\u0026thinsp;\u0026plusmn;\u0026thinsp;0.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.771\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSatisfaction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e4.59\u0026thinsp;\u0026plusmn;\u0026thinsp;0.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.205\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e4.41\u0026thinsp;\u0026plusmn;\u0026thinsp;0.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.67\u0026thinsp;\u0026plusmn;\u0026thinsp;0.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.108\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVAS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e5.71\u0026thinsp;\u0026plusmn;\u0026thinsp;2.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.63\u0026thinsp;\u0026plusmn;\u0026thinsp;2.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.206\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e1.64\u0026thinsp;\u0026plusmn;\u0026thinsp;1.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e2\u0026thinsp;\u0026plusmn;\u0026thinsp;2.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.806\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eSRS indicates Scoliosis Research Society; VAS, visual analog scale\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eLong fusion represents an accepted treatment method for Lenke 3C and 6C AIS, while it is an option in the treatment of Lenke 5C AIS[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In the case of Lenke 5C AIS, long fusion is performed in lieu of selective lumbar fusion in order to prevent the loss of TC correction. LIV is typically selected as LEV in patients with structural TL/L curves, which primarily correspond to L3 or L4[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. AO may occur in any case, as short fusions may result in postoperative decompensation due to curve progression, while long fusions may reduce the likelihood of compensation. It is therefore evident that the selection of the patient population is of paramount importance in determining the frequency of AO. The aim of this study was to evaluate Lenke 3C, 5C and 6C patients with LIV as L3 or L4 in order to construct a more homogeneous group. The frequency of AO was found to be 29.78% in this study. In a similar group of patients, Koller et al.[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] found the frequency of AO to be 34%. Several risk factors have been identified for AO, including younger age, lower Risser grade and overcorrection of the deformity[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. However, this study obtained no differences between groups in terms of these parameters.\u003c/p\u003e \u003cp\u003eThe selection of LIV is also of great importance in order to prevent AO. Yang et al. identified that LIV-stable vertebra (SV) \u0026le; -2 and LIV-end vertebra (EV)\u0026thinsp;\u0026le;\u0026thinsp;1 were associated with an elevated risk of AO. Our LIV-SV and LIV-EV values were comparable between groups (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). These findings indicate that AO is a multifactorial complication.\u003c/p\u003e \u003cp\u003eA number of studies have evaluated the occurrence of DD after AIS surgery and a variety of risk factors have been established. It has been demonstrated that coronal alignment affects the development of DD. Yeung et al. [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]demonstrated that in patients with severe AIS, there was a significant reduction in disc volume and nucleus pulposus, accompanied by coronal wedging of the vertebral body and intervertebral disc. Akazawa et al.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] observed that patients with DD exhibited a significantly greater lumbar curve at the final assessment, and that there was a positive correlation between the L3-4 wedge angle and L3-4 Pfirrmann disc grade two years after surgery. The reason for this could be that there are histological abnormalities in scoliotic intervertebral discs which result in a wedge-shaped configuration with segments that are both concave and convex, and which are subjected to differential mechanical stress[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. It seems reasonable to suggest that minimising lumbar curvatures in AIS surgery may help to reduce DD[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. However, could this paradoxically increase the risk of DD due to fewer mobile segments and increased fusion mass? As expected, the LIV translation, LIV\u0026thinsp;+\u0026thinsp;1 translation and LIVDA were markedly elevated in the AO group. Additionally, the number of fused levels was higher, and DD was observed in a greater number of segments in the AO group.\u003c/p\u003e \u003cp\u003eThe results of recent studies suggest that in addition to adjacent segments, all segments below the fusion site should be evaluated for DD during the period of follow-up. A study by Lonner et al. found that more than half of the cases of DD involved the second disc (35.5%) and third disc (20%) caudal to the LIV. The LIV of L4 was found to have the largest risk of presenting with significant DD compared to more cephalad LIVs. Although the association with AO was not investigated, the study demonstrated an association between coronal balance and DD, such as wedging of the disc adjacent to the LIV (\u0026ge;\u0026thinsp;5\u0026deg;) and LIV translation (\u0026ge;\u0026thinsp;2 cm), which resulted in a sixfold increase in DD[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In our study, the Pfirrmann score was greater in patients with LIV at L4 than in patients with L3, but the difference was not statistically significant. Green et al. performed both preoperative and postoperative MRI in 20 patients with a average follow-up of 11.8 years and showed that new disc pathology was identified in the distal unfused segments in 85% of patients, with the majority of DD occurring at L5/S1[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In the current study, we observed that the discs of L4-L5 and L5-S1 showed a statistically significant increase in Pfirrmann grade at the postoperative follow-up compared to the preoperative stage in the AO group. In the non-AO group, the only case of worsening was observed in the L5-S1 disc.\u003c/p\u003e \u003cp\u003eIt would be beneficial to consider the following questions: Does AO correlate with an increase in DD? It would be of interest to ascertain whether DD increases the frequency of AO. The findings of this study indicate that there is no association between preoperative Pfirrmann disc grade below the fusion or preoperative total Pfirrmann score and AO. However, the postoperative total Pfirrmann score was found to be significantly associated with AO. The objective of this study is to examine potential correlations rather than to ascertain a definitive cause-and-effect relationship. Nevertheless, it is challenging to ascertain which parameters are more determinative, given that the question of whether AO will develop or not is multifactorial. However, an examination of the subsequent circumstances with regard to the correlation between AO and DD revealed a statistically significant increase in Pfirrmann grade for the L5-S1 disc in the AO group compared to the Non-AO group postoperatively. This recent finding is of considerable interest. The appearance of the iliolumbar and lumbosacral ligaments, coronally oriented facets and laminae, a wedge-shaped disc, and their junctional placement make the L5-S1 level distinctive among the lower lumbar levels. Sabnis et al[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] showed that the L5-S1 mobile segment has distinct degenerative and kinematical characteristics related to DD and facet joint osteoarthritis compared to the upper lumbar mobile segments, which develop independently but not at the other lumbar levels. In our study, the L5-S1 disc degenerated postoperatively in both groups. It can be concluded that the L5-S1 disc, which is already susceptible to degeneration, is further compromised in the presence of AO. A limited sample size and a relatively short follow-up period are limitations of the study. In addition, the study lacked a control group that would have allowed evaluation of the natural history of lumbar discs in healthy subjects or in untreated AIS patients. The main strengths of the study are the consistency of the surgical technique and the homogeneity of the patient groups, as well as the availability of preoperative and postoperative magnetic resonance (MR) imaging.\u003c/p\u003e \u003cp\u003eIn conclusion, despite the absence of a direct comparison, patients with AO exhibited a significantly higher degree of DD at the L5-S1 level, although this was not the segment adjacent to the fusion. The distinctive kinematic and structural characteristics of the L5-S1 disc may be the underlying cause of this degeneration. In instances where AO develops, the primary consideration is the patient's presentation. In the absence of patient-reported symptoms and excessive curve progression, a conservative follow-up approach is the most appropriate course of action. The findings of our study indicated that there was no statistically significant difference in clinical scores between the group with AO and the group without AO. This prompts the question of what should be taken into careful consideration in patients who develop AO and are followed up. Despite the absence of significant differences in clinical outcomes between the AO and non-AO groups, we advise that patients with AO should undergo examination of the L5-S1 disc, as this may result in complications over time.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eno declaration.\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eConflict of interest :\u0026nbsp;\u003c/strong\u003eNo conflict of interest.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eFunding :\u0026nbsp;\u003c/strong\u003eNo funding.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eEthical approval :\u0026nbsp;\u003c/strong\u003eApproved by Haydarpasa Numune Training and Research Hospital Editorial Board with\u0026nbsp;2022/KK/220\u0026nbsp;number.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eAvailability of data and materials:\u003c/strong\u003e Data is available and can be sent upon request.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eAcknowledgements :\u003c/strong\u003e No acknowledgements\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eAuthors’ contribution :\u0026nbsp;\u003c/strong\u003e All of authors meet conditions 1, 2, 3 and 4.1) made substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data; or the creation of new software used in the work; 2) drafted the work or revised it critically for important intellectual content; 3) approved the version to be published; and 4) agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAkazawa T, Umehara T, Iinuma M, Asano K, Kuroya S, Torii Y, Murakami K, Kotani T, Sakuma T, Minami S, Orita S, Inage K, Shiga Y, Nakamura J, Inoue G, Miyagi M, Saito W, Eguchi Y, Fujimoto K, Takahashi H, Ohtori S, Niki H (2020) Spinal Alignments of Residual Lumbar Curve Affect Disc Degeneration after Spinal Fusion in Patients with Adolescent Idiopathic Scoliosis: Follow-up after 5 or More Years. Spine surgery and related research 4:50-56. doi:10.22603/ssrr.2019-0048\u003c/li\u003e\n\u003cli\u003eChiu CK, Tan CS, Chung WH, Mohamad SM, Kwan MK, Chan CYW (2021) Mid-long-term outcome and degeneration of the remaining unfused lumbar intervertebral disc in adolescent idiopathic scoliosis patients who had posterior spinal fusion surgery. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society 30:1978-1987. doi:10.1007/s00586-021-06874-5\u003c/li\u003e\n\u003cli\u003eDehnokhalaji M, Golbakhsh MR, Siavashi B, Talebian P, Javidmehr S, Bozorgmanesh M (2018) Evaluation of the Degenerative Changes of the Distal Intervertebral Discs after Internal Fixation Surgery in Adolescent Idiopathic Scoliosis. Asian spine journal 12:1060-1068. doi:10.31616/asj.2018.12.6.1060\u003c/li\u003e\n\u003cli\u003eEnercan M, Kahraman S, Yilar S, Cobanoglu M, Gokcen BH, Karadereler S, Mutlu A, Ulusoy LO, Ozturk C, Erturer E, Gebes E, Sanli T, Alanay A, Hamzaoglu A (2016) Does It Make a Difference to Stop Fusion at L3 Versus L4 in Terms of Disc and Facet Joint Degeneration: An MRI Study With Minimum 5 Years Follow-up. Spine deformity 4:237-244. doi:10.1016/j.jspd.2015.12.001\u003c/li\u003e\n\u003cli\u003eHristova GI, Jarzem P, Ouellet JA, Roughley PJ, Epure LM, Antoniou J, Mwale F (2011) Calcification in human intervertebral disc degeneration and scoliosis. Journal of orthopaedic research : official publication of the Orthopaedic Research Society 29:1888-1895. doi:10.1002/jor.21456\u003c/li\u003e\n\u003cli\u003eJakkepally S, Viswanathan VK, Shetty AP, Hajare S, Kanna RM, Rajasekaran S (2022) The analysis of progression of disc degeneration in distal unfused segments and evaluation of long-term functional outcome in adolescent idiopathic scoliosis patients undergoing long-segment instrumented fusion. Spine deformity 10:343-350. doi:10.1007/s43390-021-00428-x\u003c/li\u003e\n\u003cli\u003eKoller H, Enercan M, Decker S, Mehdian H, Nasto LA, Hitzl W, Koller J, Hempfing A, Hamzaoglu A (2021) Resolution of the lumbosacral fractional curve and evaluation of the risk for adding on in 101 patients with posterior correction of Lenke 3, 4, and 6 curves. Journal of neurosurgery Spine 35:471-485. doi:10.3171/2020.11.spine201313\u003c/li\u003e\n\u003cli\u003eKotwal S, Pumberger M, Hughes A, Girardi F (2011) Degenerative scoliosis: a review. HSS journal : the musculoskeletal journal of Hospital for Special Surgery 7:257-264. doi:10.1007/s11420-011-9204-5\u003c/li\u003e\n\u003cli\u003eLark RK, Yaszay B, Bastrom TP, Newton PO (2013) Adding thoracic fusion levels in Lenke 5 curves: risks and benefits. Spine 38:195-200. doi:10.1097/BRS.0b013e3182634c85\u003c/li\u003e\n\u003cli\u003eLi M, Zhao YC, Zhu XD, He SS, Wang CF, Yang CW (2010) [Analysis of posterior pedicle screw-only constructs in surgical treatment of adolescent idiopathic scoliosis with a minimum three-year follow-up]. Zhonghua wai ke za zhi [Chinese journal of surgery] 48:410-414\u003c/li\u003e\n\u003cli\u003eLonner BS, Ren Y, Upasani VV, Marks MM, Newton PO, Samdani AF, Chen K, Shufflebarger HL, Shah SA, Lefton DR, Nasser H, Dabrowski CT, Betz RR (2018) Disc Degeneration in Unfused Caudal Motion Segments Ten Years Following Surgery for Adolescent Idiopathic Scoliosis. Spine deformity 6:684-690. doi:10.1016/j.jspd.2018.03.013\u003c/li\u003e\n\u003cli\u003ePfirrmann CW, Metzdorf A, Zanetti M, Hodler J, Boos N (2001) Magnetic resonance classification of lumbar intervertebral disc degeneration. Spine 26:1873-1878. doi:10.1097/00007632-200109010-00011\u003c/li\u003e\n\u003cli\u003eTambe AD, Panikkar SJ, Millner PA, Tsirikos AI (2018) Current concepts in the surgical management of adolescent idiopathic scoliosis. The bone \u0026amp; joint journal 100-b:415-424. doi:10.1302/0301-620x.100b4.bjj-2017-0846.r2\u003c/li\u003e\n\u003cli\u003eTrobisch PD, Ducoffe AR, Lonner BS, Errico TJ (2013) Choosing fusion levels in adolescent idiopathic scoliosis. The Journal of the American Academy of Orthopaedic Surgeons 21:519-528. doi:10.5435/jaaos-21-09-519\u003c/li\u003e\n\u003cli\u003eWang Y, B\u0026uuml;nger CE, Zhang Y, Hansen ES (2012) Extensive fusion for Lenke 3C and 6C scoliosis: a two year radiographic follow-up. International orthopaedics 36:795-801. doi:10.1007/s00264-011-1331-6\u003c/li\u003e\n\u003cli\u003eWang Y, Hansen ES, H\u0026oslash;y K, Wu C, B\u0026uuml;nger CE (2011) Distal adding-on phenomenon in Lenke 1A scoliosis: risk factor identification and treatment strategy comparison. Spine 36:1113-1122. doi:10.1097/BRS.0b013e3181f51e95\u003c/li\u003e\n\u003cli\u003eYang M, Zhao Y, Yin X, Chen Z, Yang C, Li L, Li M (2018) Prevalence, Risk Factors, and Characteristics of the \u0026quot;Adding-On\u0026quot; Phenomenon in Idiopathic Scoliosis After Correction Surgery: A Systematic Review and Meta-Analysis. Spine 43:780-790. doi:10.1097/brs.0000000000002423\u003c/li\u003e\n\u003cli\u003eYeung KH, Man G, Hung A, Lam TP, Cheng J, Chu W (2021) Morphological changes of intervertebral disc in relation with curve severity of patients with Adolescent Idiopathic Scoliosis - a T2-weighted MRI study. Studies in health technology and informatics 280:37-39. doi:10.3233/shti210431\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"acta-neurochirurgica","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"anch","sideBox":"Learn more about [Acta Neurochirurgica](http://link.springer.com/journal/701)","snPcode":"701","submissionUrl":"https://submission.springernature.com/new-submission/701/3","title":"Acta Neurochirurgica","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"adding-on, degeneration, disc, adolescent idiopathic scoliosis Type of study/level of evidence: Therapeutic IV","lastPublishedDoi":"10.21203/rs.3.rs-5112797/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5112797/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e The aim of this study is to examine the association between adding-on (AO) and disc degeneration(DD) of distal unfused levels in Lenke 3C, 5C, 6C adolescent idiopathic scoliosis (AIS) \u0026nbsp;patients with a follow-up of at least two years by comparing preoperative and postoperative magnetic resonance imaging (MRI).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e 47 AIS patients (32 females and 15 males) with structural thoracolumbar/lumbar (TL/L) curves treated with long segment thoracolumbar fusion were retrospectively evaluated. Patients were divided into two groups according to the occurrence of the AO (AO and Non-AO groups). The unfused discs were graded using the MRI images according to the Pfirrmann grading method. The Scoliosis Research Society-22 (SRS-22) questionnaire and Visuel Analog Scale (VAS) were used to determine clinical outcomes.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e The frequency of AO was found to be 29.78%. Preoperative MT curve and TL/L curve angles; LIV translation, LIV disc angle, \u0026nbsp;LIV +1 translation at final follow-up and the number of fused levels were significantly higher in the AO group. Postoperative total Pfirrmann Score was significantly associated with AO. L5-S1 disc in the AO group had a statistically significant higher Pfirrmann grade than the Non-AO group. No significant association was found between the VAS and SRS-22 scores related to AO, DD or other radiological outcomes.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e Although the AO was detected at a high rate in Lenke 3C, 5C, 6C AIS patients and its association with DD in distal unfused levels was demonstrated, no impact on clinical scores was found. Furthermore, patients with AO developed significantly higher DD in L5-S1 disc, even if it is not the segment adjacent to the fusion. Even if this DD does not cause complaints in the young AIS population, L5-S1 disc should be evaluated in patients with AO, since it may cause complaints in longer follow-up. \u0026nbsp;\u003c/p\u003e","manuscriptTitle":"Disc Degeneration in Distal Unfused Segments: Cause or Consequence of Adding-On After Posterior Fusion of Lenke 3c, 5c, 6c Adolescent Idiopathic Scoliosis?","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-19 10:04:07","doi":"10.21203/rs.3.rs-5112797/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-10-10T12:35:07+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-10-08T16:22:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-09-24T17:47:22+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"232471253059871701629553834300658895038","date":"2024-09-24T17:09:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"223237346253876957931282004767372483527","date":"2024-09-24T08:32:18+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-09-22T16:49:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-09-20T04:12:30+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-09-20T04:11:51+00:00","index":"","fulltext":""},{"type":"submitted","content":"Acta Neurochirurgica","date":"2024-09-18T23:58:17+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"acta-neurochirurgica","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"anch","sideBox":"Learn more about [Acta Neurochirurgica](http://link.springer.com/journal/701)","snPcode":"701","submissionUrl":"https://submission.springernature.com/new-submission/701/3","title":"Acta Neurochirurgica","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"aeadf517-247f-496e-9344-f0a55c070875","owner":[],"postedDate":"December 19th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-01-06T16:03:39+00:00","versionOfRecord":{"articleIdentity":"rs-5112797","link":"https://doi.org/10.1007/s00701-024-06412-4","journal":{"identity":"acta-neurochirurgica","isVorOnly":false,"title":"Acta Neurochirurgica"},"publishedOn":"2025-01-02 15:57:45","publishedOnDateReadable":"January 2nd, 2025"},"versionCreatedAt":"2024-12-19 10:04:07","video":"","vorDoi":"10.1007/s00701-024-06412-4","vorDoiUrl":"https://doi.org/10.1007/s00701-024-06412-4","workflowStages":[]},"version":"v1","identity":"rs-5112797","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5112797","identity":"rs-5112797","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}