Special learning curves and clinical outcome of full-endoscopic lumbar interbody fusion

Special learning curves and clinical outcome of full-endoscopic lumbar interbody fusion | 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 Special learning curves and clinical outcome of full-endoscopic lumbar interbody fusion Guodong Yin, Jicheng He, Chengqiang Yu, Wenhao Li, Fei Xiao This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7630072/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract Background In recent years, some researchers have reported the learning curves of TLIF, MIS-TLIF, and OLIF. However, there were few reports about the learning curve of PE-LIF. Methods Data for consecutive patients with single-segment lumbar spondylolisthesis or lumbar spinal stenosis who had undergone PE-LIF with percutaneous pedicle screw fixation from January 2022 to September 2023 were retrospectively collected. We tried to divide the entire surgical process into different time segments according to surgical steps and the learning curves of each time frame were plotted out and further studied. We also reported the initial clinical results to provide experience of the safety, accuracy, and efficiency of PE-LIF directly. Results A total of 42 patients was included in the study, of which 2 patients were lost to follow-up and were excluded from the scope of the study. The duration of the surgery and each corresponding step decreased while the number of cases increased. Yet, the slope of whole operative time and each corresponding step flattened at quite different case numbers. The VAS score in low-back pain, leg pain and ODI score improved significantly for all patients after surgery and continued to improve throughout the entire follow-up. At the 1-year follow-up, excellent modified Macnab outcomes were achieved at 26 patients, good at 13, and fair at 1. The incidence rate of complications in the series was 7.5%: 1 case of cage retropulsion, 1 case of cage subsidence, 1 case of dural matter tear and no intraoperative neurovascular injury. Conclusions It is technically feasible and safe to implant an interbody fusion cage device directly through an endoscopic working cannula. It may be accelerated the process of endplates preparation under the endoscopy by introducing endplate handling equipment used in open surgery. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 INTRODUCTION Degenerative lumbar spinal disease is one kind of common disease, often leading to neurogenic claudication and radiculopathy. In the case of ineffective conservative treatments, including medication, injections, and physical therapy, surgical treatment is then indicated. The minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) procedures have been accept and widely favorable for many applications by spinal surgeons in the treatment of lumbar spondylolisthesis since 2002 [1,2] .Though it has many virtues, such as durable clinical efficacy and satisfying fusion rates with less postoperative pain, early ambulation, reducing incidence of complications, MIS-TLIF technique still needs to use retractors which may lead to muscle injury and related postoperative paravertebral muscles dysfunction [3] . In recent years, spine surgeons have developed more advanced minimally invasive techniques. Among them, the most prominent is the application of endoscopic-assisted spine surgery [4] . With advances in endoscopic facility and surgical technique, spinal surgeries are undergoing a rapid technological revolution for patients suffering from lumbar degenerative diseases. As a minimally invasive surgery, the newly reported technique has been recognized as safe and effective for its clear visualization and less damage as most surgical procedures are carried out within a rigid rod-shaped endoscope, which combines the working channel with lighting, video camera and irrigation system [5] . Nevertheless, as a new technology, percutaneous endoscopic lumbar interbody fusion(PE-LIF) remains to be a challenging task. Surgeons still require extremely familiarity with the anatomical structure and skilled hand-eye cooperation ability under endoscope [6] . In recent years, some researchers have reported the special learning curves of TLIF, MIS-TLIF, and OLIF [7–9] . However, there were few reports about the learning curve of PE-LIF [10] . In the study, we tried to divide the entire surgical process into different time segments according to surgical procedures and the characteristics of each time frame to each surgical step were further studied. We also reported the initial clinical results to provide experience of the safety, accuracy, and efficiency of PE-LIF directly. MATERIALS AND METHODS Data for consecutive patients with single-segment lumbar spondylolisthesis or lumbar spinal stenosis who had undergone PE-LIF with percutaneous pedicle screw fixation from January 2022 to September 2023 were retrospectively collected. These patients were enrolled for suffering from persisting lower back pain or claudication after 4 weeks of conservative treatments at least. ALL patients were diagnosed by two senior attending doctors based on combinations of clinical manifestation and imaging evidence including X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) ( Fig. 1 – 5 ) . All surgeries were performed by two deputy chief physicians. The clinical demographic and radiographic characteristics of the patients are shown in Table 1 . Table 1 Patient demographic characteristics(n = 40). Characteristics Value Age (years, mean ± SD) 53.48 ± 7.81 Gender (female) 17(42.5%) Levels (n = 40) L3/4 6 (15.0%) L4/5 14(35.0%) L5/S1 20 (50.0%) Incidence of comorbidities Hypertension 13 (32.5%) Diabetes mellitus 8(20.0%) Coronary artery disease 3 (7.5%) Respiratory diseases 1 (2.5%) follow-up (months) 14.01 ± 2.35 Body mass index (kg/m2) 24.93 ± 3.17 Normally distributed variables are presented as the means ± SD; non-normal continuous variables are presented as the medians (range); categorical variables are presented as frequencies (%). The inclusion criteria were defined as follows: (1) discogenic low back pain, (2) single segmental degenerative lumbar stenosis, (3) degenerative or isthmic spondylolisthesis (grade I/II, according to the Meyerding standard), (4) degenerative lumbar spinal instability requiring stability and fusion, (5) only unilateral decompression and bone graft fusion. The exclusion criteria were (1) accompanied by congenital spinal deformity, (2) previous lumbar fusion surgery, (3) a history of vertebral fracture, spinal tumor or infection, (4) Inability to tolerate PE-LIF surgery for other reasons. Surgical Technique. A Delta Endoscopic System (Joimax GmbH, Karlsruhe, Germany) was used for all cases in our study. Under general anesthesia, the patient was positioned prone on a radiolucent table with abdomen suspended to lower abdominal pressure and therefore to reduce operative field bleeding. The entire surgical procedure was divided into four segments in chronological order. Step 1 Screw guidewires insertion Initially, the operation puncture angle and projection points for screw insertion on the skin was designed and confirmed under the guidance of the C-arm. A horizontal incision of about 1.5 cm in length was made above the corresponding segment with blade. Through the surrounding tissue and fascia, the spinal puncture needles were inserted and placed in a sequence. After confirmation by the view of the C-arm, the puncture needle was gradually replaced by a guidewire. Step 2 Decompression of dura sac and nerve root The skin entry point of percutaneous endoscope was located at the same point of the inferior vertebral pedicle screw guidewires. After guidewire/rod replacement and graded tissue dilations, an endoscopic system with an outer diameter of 10mm, an inner diameter of 6mm, was connected and placed into the working cannula. The articular processes of operative segment and ligamentum flavum were exposed, and the inferior articular process and partial lamina of upper vertebrae were removed with visualizing trephine under Delta Endoscopic System supervision. Moreover, the part superior articular process (SAP) of the lower vertebrae was also cut off to expose the Kambin triangle. Afterwards the dura sac and transverse nerve root were revealed by excision of the ligamentum flavum and hyperplastic bone. Meanwhile, the ipsilateral nerve root decompression was carried out by the cannula direction modulation. Step 3 Endplate preparation and cage implantation The resection of the intervertebral disc was performed under endoscopic visualization ( Fig. 6 ) . Under the monitoring of C-arm, discectomy and endplate decortication was underwent with the instruments, such as raspatories, pituitary rongeurs, and curettes of different sizes. Model cages of varying sized height and length were implanted through the cannula under the C-arm fluoroscopic monitoring ( Fig. 7 ) . Once confirming the appropriate size, the model cage was taken out. Autogenous bone excised from SAP and allograft bone were packed into the anterior disc space and the choosing cage filled with allograft bone was inserted into the intervertebral space in appropriate depth under fluoroscopic and endoscopic visualization ( Fig. 8 、9) . After the cage implantation, the dura sac and transverse nerve root were checked once more for inspection of satisfactory decompression under endoscopic view ( Fig. 10 ) . Step 4 Percutaneous pedicle screws installation Finally, percutaneous pedicle screws and bilateral connecting rods were then installed, and the views of screws and cage were verified under C-arm. Following thorough hemostasis and irrigation of the operative region, a drainage tube was insert and the incision was closed ( Fig. 11 ) . Before discharge, all patient had a re-examination of the lumbar X-ray ( Fig. 12 、13) . Outcome Measurements The clinical data of the patients were recorded such as age, sex, diagnosis, surgical segment, operating time, complications, length of stay, and clinical outcomes. Visual analog scale (VAS) for back pain and leg pain, Oswestry Disability Index (ODI), and The Modified MacNab criteria were used to evaluate the before and post operative clinical results. Statistical Analysis Statistical analysis was performed using SPSS version 20.0 (SPSS Inc., Chicago, IL). Data were presented as means ± standard deviation. Comparisons of clinical results before and after the operations were analyzed using paired t-test. A regression analysis of operative time (y axis), and the number of cases (x axis) were conducted to characterize the learning curve of PE-LIF. Statistical significance was set at p < 0.05. RESULTS Demographic Data A total of 42 patients were included in the study, of which 2 patients were lost to follow-up and were excluded from the scope of the study. The remaining forty patients (17, female;23, male) who underwent endoscopic lumbar fusion surgery were enrolled in this retrospective study ultimately. The mean patient age was 53:48 ± 7:81 years. All patients were performed single-level TLIF. The segments of surgical distribution were 6 patients in L3/4, 14 in L4/5, and 20 in L5/S1. Patient characteristics were displayed in Table 1 . Learning Curve and Clinical Outcome Using a regression locally weighted scatterplot smoothing curve, the duration of the surgery and each corresponding step decreased while the number of cases increased. Yet, the slope of whole operative time and each corresponding step flattened at quite different case number ( Fig. 14 – 18 ) . The VAS score in low-back pain, leg pain and ODI score improved significantly for all patients after surgery and continued to improve throughout the entire follow-up step ( Table 2 ) . At the 1-year follow-up, excellent modified Macnab outcomes were achieved at 26 patients, good at 13, and fair at 1. Table 2 Comparisons of clinical data at each follow-up time point Score Preoperative 1 week Postoperative 3 Months postoperative 1 year postoperative final follow-up VAS of low back pain 6.22 ± 0.71 3.03 ± 0.61* 2.54 ± 0.59* 2.06 ± 0.68* 1.38 ± 0.70* VAS of sciatica 6.98 ± 0.77 2.18 ± 0.69* 1.63 ± 0.57* 1.48 ± 0.62* 1.09 ± 0.62* ODI 50.60 ± 7.46 22.53 ± 5.16* 17.15 ± 3.05* 11.30 ± 3.50* 9.15 ± 2.83* Values were presented as mean ± standard deviation. *Paired t-test. p < 0.05, statistically significant differences. Complications The incidence rate of complications in the series was 7.5%: 1 case of cage retropulsion, 1 case of cage subsidence, 1 case of dural matter tear and no intraoperative neurovascular injury. After one month of conservative treatment such as reducing ambulation, the 2 cases of cage shifting were controlled, and the cage movements were not significantly aggravated. The patient with dural tears had no obvious exudation in the wound after the drainage tube was removed 2 days after the operation, and the patient had no discomfort such as dizziness and fever. DISCUSSION In terms of the minimally invasive TLIF surgery, the mainstream surgical procedures may fall into three groups according to the assisted surgical system used: full-endoscopic TLIF, bi-portal endoscopic TLIF and minimally invasive TILF (MIS-TLIF). Compared with the latter two, PE-LIF may demonstrate less tissue damage and achieve satisfactory postoperative clinical rehabilitation [11] . In process of mini-invasive TLIF surgery, facet joint resection is a crucial step to obtain adequate exposure of the Kambin triangle which usually might not provide enough space for patients with lumbar spondylolisthesis. Many spinal surgeons have attempted to perform full-endoscopic LIF surgery using posterior interlaminar or lateral transforaminal approaches. Researchers have offered careful contrast of these two techniques [12,13] . The interlaminar approach has obvious advantages in central vertebral canal decompression, friendly overlooking visual angles, as well as the convenience to resolve some specific types of disc herniation such as huge herniation and intervertebral disc calcification [14] . However, the patients might suffer from more stretching of dura sac and transverse nerve root. Meanwhile, the posterior approach decreased the extent of the facet joints resections which may result in incomplete exposure and decompression of the exiting nerve root. The transforaminal approach, by contrast, was designed to reduce stretching of dura sac and transverse nerve root during exposure of the Kambin triangle [15] . However, this manipulation needs to open and expand the intervertebral foramen by resection of ventral articular process which might be a hazard to damage exiting nerve root [16] . In fact, the approach has always faced another challenge of incomplete decompression of contralateral lateral recess, which is determined by the anatomical characteristics. Whatever the approach you choose, the ability to locate safely and quickly at the aimed lumbar facet joint would be critical to successful completement of surgery. We accomplish the endoscopic surgical procedure in a similar conventional open pattern with the first confirmation of rapid localization at the aimed lumbar facet joint with the aid of intraoperative fluoroscopy and endoscopy. A learning curve has delineated the characteristics of the whole procedure in fact. However, the proportion of time allocation and the degree of the different steps adaptation in the whole surgical process are not the same. The greatest dilemma for the spreading of endoscopic spine surgery technology is the steep learning curve. Most researchers usually select operative time and case number as Y-axis and X-axis of learning curve coordinate axis when the learning curve of PE-LIF is mentioned [17] . However, few studies have segmented the duration of surgery according to procedure and examined the corresponding changes with the increasing case numbers performed. We divided whole operation time into four steps in accordance with the operation procedures, namely guide wire placement (step1), spinal canal decompression (step 2), cage placement (step 3) and installation of pedicle screw system (step 4). From analysis of the relationship between each time steps and the corresponding number of surgical cases, we can infer that the learning curve of each procedure is characteristic. Normally, PE-LIF is technically fastidious for surgeons without enough endoscopic experience and is always accompanied by a long and steep learning curve. From Figs. 14 to 18 , we can find out the steepness of learning curve on behalf of each step was quite different, as was the number of cases that reached a stable platform. A trend of longer and gradual decline was on display of the learning curves along with the increasing cases numbers in steps 2 and 3. The time of step 1 (Fig. 15 ) and 4 (Fig. 18 ) reach the learning plateau (5–20 cases) was relatively quick, while steps 2–3 (Fig. 16 , 17 ) take more time (20–40 cases) to reach. It means that the procedures of spinal canal decompression and cage implantation need more training to achieve a stable level. It could also be inferred that the process of guide wire placement(step1) and installation of pedicle screw system(step4) may be much easier to grasp for unexperienced surgeons. Therefore, quickly location, nerve decompression and dealing with the endplate might be vital for successful and rapid completion in total endoscopic lumbar fusion surgery under the endoscopic view [18] . In general, the more endoscopically experienced the surgeon is, the safer and more efficient the surgical procedure will be [19] . Owing to the direct endoscopic view, preparation of endplates can be visible to avoid injury to the endplate which might result in cage subsidence and failure fixation [20] . Although the meticulous processing of cartilage endplate is impressive, the efficiency is not satisfactory [21] . We have greatly accelerated the process of endplates preparation under the endoscopy by introducing endplate handling equipment used in open surgery. It turns out that the performance of regular raspatories, pituitary rongeurs, and curettes, although invisible, is still safe and efficient under the shielding protection of sheath tube. The expandable cage was designed to increase the height of intervertebral space and improve sagittal alignment in recent reports [22][23] . However, it may lead to gradual cage subsidence for elderly patients who suffered from osteoporosis and the cost of this special cage determines its limited use at last [24][25] . In our serials, we implant ordinary PLIF cages through combined removable tube into intervertebral space. The diameter of the tube determines that the maximum size of the implanted fusion cage cannot be beyond size 12. In terms of clinical results, it was observed significant improvement in VAS, ODI score and satisfactory Macnab outcomes. We are reporting on a new percutaneous endoscopic lumbar interbody fusion surgery. We segmented the duration of surgery according to procedure and figured out the learning curve of each procedure. The central challenge of this procedure is to complete endplate preparation rapidly for fusion and insert a suitable sized interbody cage through a channel lean on Kambin’s triangle [26] . We have accelerated the process of endplates preparation under the endoscopy by introducing endplate handling equipment used in open surgery which could solve the above problem. The incidence rate of complications in the series was 7.5%: 1 case of cage retropulsion, 1 case of cage subsidence, 1 case of dural matter tear and no intraoperative neurovascular injury. In this serial, it was observed significant improvement in VAS, ODI score and satisfactory Macnab outcomes. To our knowledge, the findings have not been reported previously. Declarations AVAILABILITY OF DATA AND MATERIALS The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request. ETHICS APPROVAL AND CONSENT TO PARTICIPATE This study has obtained ethics approval and consent of the Ethics Committee of the People's Hospital of Guangxi Zhuang Autonomous Region. FUNDING A grant from the Guangxi Natural Science Foundation Project supported this work by the Guangxi science and technology department (2024GXNSFAA010303). Clinical trial number: not applicable. Conflicts of Interest A grant from the Guangxi Natural Science Foundation Project supported this work by the Guangxi science and technology department (2024GXNSFAA010303). The other authors declare that they have no conflicts of interest concerning the materials/methods used in this study or the findings described in this paper. References Lin E. Y., Kuo Y. K. & Kang Y. N., "Effects of three common lumbar interbody fusion procedures for degenerative disc disease: A network meta-analysis of prospective studies," Int J Surg , Vol.60(2018), pp.224-230. Kim J. S., Jung B. & Lee S. H., "Instrumented Minimally Invasive Spinal-Transforaminal Lumbar Interbody Fusion (MIS-TLIF): Minimum 5-Year Follow-Up With Clinical and Radiologic Outcomes," Clin Spine Surg , Vol.31, No.6(2018), pp.E302-E309. Ao S., Zheng W. & Wu J. et al., "Comparison of Preliminary clinical outcomes between percutaneous endoscopic and minimally invasive transforaminal lumbar interbody fusion for lumbar degenerative diseases in a tertiary hospital: Is percutaneous endoscopic procedure superior to MIS-TLIF? A prospective cohort study," Int J Surg , Vol.76(2020), pp.136-143. Xiaobing Z., Xingchen L. & Honggang Z. et al., ""U" route transforaminal percutaneous endoscopic thoracic discectomy as a new treatment for thoracic spinal stenosis," Int Orthop , Vol.43, No.4(2019), pp.825-832. Zhao X. B., Ma H. J. & Geng B. et al., "Early Clinical Evaluation of Percutaneous Full-endoscopic Transforaminal Lumbar Interbody Fusion with Pedicle Screw Insertion for Treating Degenerative Lumbar Spinal Stenosis," Orthop Surg , Vol.13, No.1(2021), pp.328-337. Jacquot F. & Gastambide D., "Percutaneous endoscopic transforaminal lumbar interbody fusion: is it worth it?" Int Orthop , Vol.37, No.8(2013), pp.1507-1510. Xu Y. F., Le XF & Tian W. et al., "Computer-assisted, minimally invasive transforaminal lumbar interbody fusion: One surgeon's learning curve A STROBE-compliant article," Medicine (Baltimore) , Vol.97, No.27(2018), p.e11423. Brusko G. D. & Wang M. Y., "Endoscopic Lumbar Interbody Fusion," Neurosurg Clin N Am , Vol.31, No.1(2020), pp.17-24. Kumar A., Merrill R. K. & Overley S. C. et al., "Radiation Exposure in Minimally Invasive Transforaminal Lumbar Interbody Fusion: The Effect of the Learning Curve," Int J Spine Surg , Vol.13, No.1(2019), pp.39-45. Zhao T., Dai Z. & Zhang J. et al., "Determining the learning curve for percutaneous endoscopic lumbar interbody fusion for lumbar degenerative diseases," J Orthop Surg Res , Vol.18, No.1(2023), p.193. Lin E. Y., Kuo Y. K. & Kang Y. N., "Effects of three common lumbar interbody fusion procedures for degenerative disc disease: A network meta-analysis of prospective studies," Int J Surg , Vol.60(2018), pp.224-230. Ju C. I. & Lee S. M., "Complications and Management of Endoscopic Spinal Surgery," Neurospine , Vol.20, No.1(2023), pp.56-77. Macki M., Hamilton T. & Haddad Y. W. et al., "Expandable Cage Technology-Transforaminal, Anterior, and Lateral Lumbar Interbody Fusion," Oper Neurosurg , Vol.21, No.Suppl 1(2021), pp.S69-S80. Chen Z., Wang X. & Cui X. et al., "Transforaminal Versus Interlaminar Approach of Full-Endoscopic Lumbar Discectomy Under Local Anesthesia for L5/S1 Disc Herniation: A Randomized Controlled Trial," Pain Physician , Vol.25, No.8(2022), pp.E1191-E1198. Takebayashi K., Oshima Y. & Fujita M. et al., "Comparison of the Interlaminar and Transforaminal Approaches for Full-endoscopic Discectomy for the Treatment of L4/5 Lumbar Disc Herniation," Neurol Med Chir (Tokyo) , Vol.63, No.7(2023), pp.313-320. Phani K. S. & Sudhir G., "Minimally invasive transforaminal lumbar interbody fusion - A narrative review on the present status," J Clin Orthop Trauma , Vol.22(2021), p.101592. Zhao X. B., Ma H. J. & Geng B. et al., "Early Clinical Evaluation of Percutaneous Full-endoscopic Transforaminal Lumbar Interbody Fusion with Pedicle Screw Insertion for Treating Degenerative Lumbar Spinal Stenosis," Orthop Surg , Vol.13, No.1(2021), pp.328-337. Zhao T., Dai Z. & Zhang J. et al., "Determining the learning curve for percutaneous endoscopic lumbar interbody fusion for lumbar degenerative diseases," J Orthop Surg Res , Vol.18, No.1(2023), p.193. Wu J., Liu H. & Ao S. et al., "Percutaneous Endoscopic Lumbar Interbody Fusion: Technical Note and Preliminary Clinical Experience with 2-Year Follow-Up," Biomed Res Int , Vol.2018(2018), p.5806037. Heo D. H., Lee D. C. & Kim H. S. et al., "Clinical Results and Complications of Endoscopic Lumbar Interbody Fusion for Lumbar Degenerative Disease: A Meta-Analysis," World Neurosurg , Vol.145(2021), pp.396-404. Ishihama Y., Morimoto M. & Tezuka F. et al., "Full-Endoscopic Trans-Kambin Triangle Lumbar Interbody Fusion: Surgical Technique and Nomenclature," J Neurol Surg A Cent Eur Neurosurg , Vol.83, No.4(2022), pp.308-313. Lee S. B., Yoon J. & Park S. J. et al., "Expandable Cages for Lumbar Interbody Fusion: A Narrative Review," J Clin Med , Vol.13, No.10(2024). Huang C. C., Brena K. R. & Tabarestani T. Q. et al., "Minimally-invasive trans-facet lumbar interbody fusion using a dual-dimension expandable cage: preliminary results of a multi-institutional retrospective study," J Spine Surg , Vol.10, No.3(2024), pp.403-415. Calvachi-Prieto P., McAvoy M. B. & Cerecedo-Lopez C. D. et al., "Expandable Versus Static Cages in Minimally Invasive Lumbar Interbody Fusion: A Systematic Review and Meta-Analysis," World Neurosurg , Vol.151(2021), pp.e607-e614. Subramanian T., Merrill R. K. & Shahi P. et al., "Predictors of Subsidence and its Clinical Impact After Expandable Cage Insertion in Minimally Invasive Transforaminal Interbody Fusion," Spine (Phila Pa 1976) , Vol.48, No.23(2023), pp.1670-1678. Pholprajug P., Kotheeranurak V. & Liu Y. et al., "The Endoscopic Lumbar Interbody Fusion: A Narrative Review, and Future Perspective," Neurospine , Vol.20, No.4(2023), pp.1224-1245. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 31 Mar, 2026 Reviews received at journal 31 Mar, 2026 Reviewers agreed at journal 21 Mar, 2026 Reviews received at journal 10 Nov, 2025 Reviewers agreed at journal 23 Oct, 2025 Reviewers invited by journal 23 Oct, 2025 Editor assigned by journal 20 Sep, 2025 Submission checks completed at journal 18 Sep, 2025 First submitted to journal 16 Sep, 2025 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7630072","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":538810606,"identity":"26580210-725a-44b9-980c-b9996f6947cf","order_by":0,"name":"Guodong Yin","email":"","orcid":"","institution":"The People's Hospital of Guangxi Zhuang Autonomous Region","correspondingAuthor":false,"prefix":"","firstName":"Guodong","middleName":"","lastName":"Yin","suffix":""},{"id":538810607,"identity":"9b748bf5-d920-47d0-a003-8c6a4cf4f04c","order_by":1,"name":"Jicheng He","email":"","orcid":"","institution":"The People's Hospital of Guangxi Zhuang Autonomous Region","correspondingAuthor":false,"prefix":"","firstName":"Jicheng","middleName":"","lastName":"He","suffix":""},{"id":538810609,"identity":"8c015b66-693b-441a-81d9-ecb4060133e2","order_by":2,"name":"Chengqiang Yu","email":"","orcid":"","institution":"The People's Hospital of Guangxi Zhuang Autonomous Region","correspondingAuthor":false,"prefix":"","firstName":"Chengqiang","middleName":"","lastName":"Yu","suffix":""},{"id":538810610,"identity":"91111aa6-901f-4c21-88d7-ff17cd8a4fe3","order_by":3,"name":"Wenhao Li","email":"","orcid":"","institution":"The People's Hospital of Guangxi Zhuang Autonomous Region","correspondingAuthor":false,"prefix":"","firstName":"Wenhao","middleName":"","lastName":"Li","suffix":""},{"id":538810612,"identity":"e893997d-7e38-40e7-b35e-ed7a131ee791","order_by":4,"name":"Fei Xiao","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAw0lEQVRIie3QsQrCMBCA4ZNAptSs6VJ9hJMuDn0Tl3Tp5t6hSEGoi9DV9xCcrwQ6FXyFgi9QcHUwujlI4uaQf74P7g4gFPrHGAFNqIRkzIx+hGvoTuU6iQ+8QG/CxFCmeBVL5SWwZx1FjcrPRgBClW2cJG64ptiSi4lohL7Y1i4iF0ek1ZvMNc5q4yacy4ny12J7gcqLSC6AaFApMl9ib8GuLlWijH2y9rnFfux2f+BOyNaYcaoyN/lM/zYeCoVCoW89AZpMPok7LsupAAAAAElFTkSuQmCC","orcid":"","institution":"The 923rd Hospital of PLA","correspondingAuthor":true,"prefix":"","firstName":"Fei","middleName":"","lastName":"Xiao","suffix":""}],"badges":[],"createdAt":"2025-09-16 11:53:34","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7630072/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7630072/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":95228239,"identity":"e75c2c71-a95a-4a8c-bc89-0bafd0c21349","added_by":"auto","created_at":"2025-11-05 16:33:31","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":4276748,"visible":true,"origin":"","legend":"","description":"","filename":"speciallearningcurvesandclinicaloutcomeoffullendoscopiclumbarinterbodyfusion.docx","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/931c617e7e47e5f82825529d.docx"},{"id":95227347,"identity":"7c5c11f6-0a05-45bc-98be-d130dd3a0775","added_by":"auto","created_at":"2025-11-05 16:32:24","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":6769,"visible":true,"origin":"","legend":"","description":"","filename":"bb3e21e91ed5458788ddfa75f0c701a5.json","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/3f03de11b28e292baa0f9c17.json"},{"id":95228243,"identity":"541048cb-46d7-4481-8fa9-6a80ed7e1fbe","added_by":"auto","created_at":"2025-11-05 16:33:31","extension":"doc","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":23040,"visible":true,"origin":"","legend":"","description":"","filename":"conflictofinterest.doc","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/f93535d6e56e35fdd56a39f6.doc"},{"id":95172558,"identity":"db094b57-dc01-4f77-a253-bb2d35050b97","added_by":"auto","created_at":"2025-11-05 06:39:45","extension":"xml","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":58500,"visible":true,"origin":"","legend":"","description":"","filename":"bb3e21e91ed5458788ddfa75f0c701a51enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/9b4a18b12262657ad8bf4d34.xml"},{"id":95226970,"identity":"6d31a3aa-b6ce-44f2-8d9e-d230bfc0a194","added_by":"auto","created_at":"2025-11-05 16:31:57","extension":"eps","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":594,"visible":true,"origin":"","legend":"","description":"","filename":"drawingimage2.eps","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/25ddee03195be913493a3d1b.eps"},{"id":95226275,"identity":"83fcb08f-7e1a-48e6-a12c-2c1e946a6d7b","added_by":"auto","created_at":"2025-11-05 16:30:51","extension":"png","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":330308,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/21c6c177a04303a513d0e09c.png"},{"id":95172580,"identity":"8bfaa3d4-3ab6-4a32-9385-2f5b0e069ec0","added_by":"auto","created_at":"2025-11-05 06:39:46","extension":"jpeg","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":179420,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage10.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/9b77fac275e7f5d2927f59f7.jpeg"},{"id":95228251,"identity":"f58a99d1-0158-47a2-96a5-f737ce64fb39","added_by":"auto","created_at":"2025-11-05 16:33:32","extension":"jpeg","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":409389,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage11.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/7a3bf57e497cb35a4fa91fdb.jpeg"},{"id":95172563,"identity":"e8ed6624-4c23-4931-840f-257ece788e53","added_by":"auto","created_at":"2025-11-05 06:39:45","extension":"jpeg","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":121192,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage12.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/6867bcca3223ad220d9a669c.jpeg"},{"id":95172567,"identity":"170c70cd-621c-4fba-816a-ea82ad04e6fd","added_by":"auto","created_at":"2025-11-05 06:39:45","extension":"jpeg","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":142568,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage13.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/04f5547e349e49873ba3a424.jpeg"},{"id":95226440,"identity":"fc145009-5442-49b1-978a-95addd53c16b","added_by":"auto","created_at":"2025-11-05 16:31:07","extension":"jpeg","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":154956,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage14.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/912ea60de7f3764e0344db91.jpeg"},{"id":95172619,"identity":"210f9621-4ff1-422f-842e-aee3811bddff","added_by":"auto","created_at":"2025-11-05 06:39:49","extension":"png","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":17103,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage15.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/9d236167e570cf8eae72bbe9.png"},{"id":95226697,"identity":"d2d7d4c7-4d10-4f5b-8b8a-847fcbbcc72d","added_by":"auto","created_at":"2025-11-05 16:31:39","extension":"png","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":15147,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage16.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/a936005c30a209648f504257.png"},{"id":95172568,"identity":"13a64569-a53a-4b04-ad5a-aecf477d9bea","added_by":"auto","created_at":"2025-11-05 06:39:45","extension":"png","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":15880,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage17.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/21c695053efd69775fba8277.png"},{"id":95229104,"identity":"de5e82b5-1591-4929-94d8-93dbdd3de9e7","added_by":"auto","created_at":"2025-11-05 16:34:27","extension":"png","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":16558,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage18.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/dd225c8edd08978deaa8dc2b.png"},{"id":95172576,"identity":"f57e2c0f-128d-45ce-af93-30950cbb3d78","added_by":"auto","created_at":"2025-11-05 06:39:46","extension":"png","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":15112,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage19.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/41ba80b25ed6b202f1bd3bdb.png"},{"id":95172594,"identity":"da2cd524-31a8-4f3b-b1f7-e12951d4516c","added_by":"auto","created_at":"2025-11-05 06:39:47","extension":"jpeg","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":275864,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/7fc1d3be1cf9951b48c681a3.jpeg"},{"id":95172590,"identity":"5ad919e4-3d83-4d0d-84e3-1852a4a1e342","added_by":"auto","created_at":"2025-11-05 06:39:47","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":216855,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/1baac7dfe891840ffec4bfbf.png"},{"id":95226325,"identity":"51d4438c-b45e-4b5d-b35a-81b01d51eb11","added_by":"auto","created_at":"2025-11-05 16:30:57","extension":"jpeg","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":261288,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/d1773f024dc9867b43147a46.jpeg"},{"id":95172595,"identity":"906b46e2-f789-49e3-a34c-85ab439cf59c","added_by":"auto","created_at":"2025-11-05 06:39:47","extension":"jpeg","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":457697,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/5a7df92241eeede76b63e3bf.jpeg"},{"id":95226517,"identity":"0f848279-4883-4d8e-b8bd-88e1337d5c26","added_by":"auto","created_at":"2025-11-05 16:31:18","extension":"jpeg","order_by":21,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":405995,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/474ee2a1897c07af8257dec8.jpeg"},{"id":95229108,"identity":"d17633c5-c21a-43cc-baac-dd038c075189","added_by":"auto","created_at":"2025-11-05 16:34:28","extension":"jpeg","order_by":22,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":279074,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage7.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/591ca1e678a465ebc1c100d9.jpeg"},{"id":95172611,"identity":"1470b66f-f986-40e6-9ec7-f522319a85c1","added_by":"auto","created_at":"2025-11-05 06:39:48","extension":"jpeg","order_by":23,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":185276,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage8.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/3c4122752c48734d94d7fe5b.jpeg"},{"id":95172592,"identity":"64c49183-d964-4562-a17b-bd1ce62bd62d","added_by":"auto","created_at":"2025-11-05 06:39:47","extension":"jpeg","order_by":24,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":139669,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage9.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/22246ea11a99e617705dddc2.jpeg"},{"id":95227454,"identity":"b777826f-a751-45e3-9b45-e66ccc0f6c07","added_by":"auto","created_at":"2025-11-05 16:32:30","extension":"png","order_by":25,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":73159,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/fe16579f305e0819f75c8a38.png"},{"id":95172591,"identity":"103ab5f8-a7fe-442b-a0a2-2753c0534432","added_by":"auto","created_at":"2025-11-05 06:39:47","extension":"png","order_by":26,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":153694,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/ce4109624d80a63b95641bdf.png"},{"id":95172583,"identity":"d49e11b6-68ce-4ebd-9070-43d2f6879b1a","added_by":"auto","created_at":"2025-11-05 06:39:46","extension":"png","order_by":27,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":283016,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage11.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/f0c30c2cb39317baa31b2847.png"},{"id":95226385,"identity":"a88169d9-ae26-4d91-bd9c-6cf19459ec5f","added_by":"auto","created_at":"2025-11-05 16:31:03","extension":"png","order_by":28,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":84155,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage12.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/419c7134847ee1c5a78e1980.png"},{"id":95227248,"identity":"89105cb0-fa6a-4ad8-8617-02889b62a1e9","added_by":"auto","created_at":"2025-11-05 16:32:17","extension":"png","order_by":29,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":133011,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage13.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/4481e0bdbd02c0b84076b699.png"},{"id":95172616,"identity":"a0ddcd92-07ba-43f0-917f-524e30853aec","added_by":"auto","created_at":"2025-11-05 06:39:48","extension":"png","order_by":30,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":142163,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage14.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/8e9a718113fa6f01bb3bf200.png"},{"id":95228733,"identity":"56c9b32b-3a89-43c2-a406-e583458b3ffe","added_by":"auto","created_at":"2025-11-05 16:34:05","extension":"png","order_by":31,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":10350,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage15.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/83f788bb2a468f124bf60f68.png"},{"id":95172641,"identity":"d8910f4d-121d-446b-9e9f-e189d5f5e3e7","added_by":"auto","created_at":"2025-11-05 06:39:50","extension":"png","order_by":32,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":9510,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage16.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/43306b0887d7f9b705383007.png"},{"id":95172612,"identity":"ad7d77e9-3615-44bd-97f5-f20284d311a7","added_by":"auto","created_at":"2025-11-05 06:39:48","extension":"png","order_by":33,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":9632,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage17.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/853b3992a210e3d98cbcef92.png"},{"id":95172613,"identity":"a3aff767-19e3-4735-8f53-aaefc0926728","added_by":"auto","created_at":"2025-11-05 06:39:48","extension":"png","order_by":34,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":9980,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage18.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/a303325639e17eeea47c8e57.png"},{"id":95228005,"identity":"a0cd2502-0ee4-471d-82f4-764a51345982","added_by":"auto","created_at":"2025-11-05 16:33:17","extension":"png","order_by":35,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":9320,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage19.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/07113a28268242898b9bb59f.png"},{"id":95172618,"identity":"cd7dceaf-b25c-416d-a6ea-6ab723c02f05","added_by":"auto","created_at":"2025-11-05 06:39:49","extension":"png","order_by":36,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":83059,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/c2913ba1dd571d59a62c70c6.png"},{"id":95228034,"identity":"253f6fd3-fe32-4c07-95fd-11d048a7aa44","added_by":"auto","created_at":"2025-11-05 16:33:19","extension":"png","order_by":37,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":211323,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/48a36a488d788d99ef2c2c87.png"},{"id":95172599,"identity":"55b25477-30e6-4e57-b376-4cea043cf34b","added_by":"auto","created_at":"2025-11-05 06:39:47","extension":"png","order_by":38,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":76118,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/345d4ae0e316a9589d290fea.png"},{"id":95172597,"identity":"58c30af5-5814-4308-b843-0e24951d1f10","added_by":"auto","created_at":"2025-11-05 06:39:47","extension":"png","order_by":39,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":114222,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/2c1560a39f8f536e0e9f659e.png"},{"id":95172602,"identity":"6a3291ea-85fa-4cb7-9f2e-6162e927ee26","added_by":"auto","created_at":"2025-11-05 06:39:47","extension":"png","order_by":40,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":136157,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/c699e40551b7e2582494b98e.png"},{"id":95228241,"identity":"690e5b94-453b-482d-a82f-045c10c8122c","added_by":"auto","created_at":"2025-11-05 16:33:31","extension":"png","order_by":41,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":194692,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/06b35a95482f0d78f43b4189.png"},{"id":95172605,"identity":"bfd39db1-d6fc-497d-8756-b39226d34687","added_by":"auto","created_at":"2025-11-05 06:39:48","extension":"png","order_by":42,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":173143,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/7263d379cacdc2a62e7dcb7e.png"},{"id":95228178,"identity":"0b561c47-fa86-4d87-a44f-d70d14e936ae","added_by":"auto","created_at":"2025-11-05 16:33:27","extension":"png","order_by":43,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":114085,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/39170f9f2b010d1fbf32ec60.png"},{"id":95172609,"identity":"800c9cf6-0195-46af-95e3-7ff85efed5d7","added_by":"auto","created_at":"2025-11-05 06:39:48","extension":"xml","order_by":44,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":57185,"visible":true,"origin":"","legend":"","description":"","filename":"bb3e21e91ed5458788ddfa75f0c701a51structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/717a312acde8f4988b48a9cf.xml"},{"id":95172610,"identity":"80a29e8c-ce84-41c1-b68d-0e63ebacfeca","added_by":"auto","created_at":"2025-11-05 06:39:48","extension":"html","order_by":45,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":67917,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/289748d85fa451cb70c16da6.html"},{"id":95172565,"identity":"08056fa6-a078-4b9c-acbd-9027cac18d01","added_by":"auto","created_at":"2025-11-05 06:39:45","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":222003,"visible":true,"origin":"","legend":"\u003cp\u003ePosterior-anterior (AP) radiography images.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/4560d2886ad51d6a0d037b4b.png"},{"id":95226969,"identity":"b28f3ddf-86b6-4a21-8b70-8a8243e37d58","added_by":"auto","created_at":"2025-11-05 16:31:57","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":146943,"visible":true,"origin":"","legend":"\u003cp\u003eLateral radiography images. The black arrow indicates the site of the vertebral isthmus diastasis.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/7adf6479ba460c8698369592.png"},{"id":95172615,"identity":"26836430-6144-427f-9d75-bebc7ff6fe97","added_by":"auto","created_at":"2025-11-05 06:39:48","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":127626,"visible":true,"origin":"","legend":"\u003cp\u003eLateral radiography images in flexion showing lumbar spine mobility and stability. The black arrow indicates the site of the vertebral isthmus diastasis. The yellow arrow indicates the site of the lumbar spondylolisthesis.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/9091f02a92207d92b3fabb4b.png"},{"id":95227810,"identity":"c671a55a-93ba-4896-97c7-b79c07b31b0f","added_by":"auto","created_at":"2025-11-05 16:32:59","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":135338,"visible":true,"origin":"","legend":"\u003cp\u003eLateral radiography images in extension showing lumbar spine mobility and stability. The black arrow indicates the site of the vertebral isthmus diastasis. The yellow arrow indicates the site of the lumbar spondylolisthesis.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/51e47584e310ae8fc73bc2e9.png"},{"id":95172564,"identity":"2036b758-7320-48ed-bcdb-c794bf35d2e8","added_by":"auto","created_at":"2025-11-05 06:39:45","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":497584,"visible":true,"origin":"","legend":"\u003cp\u003eThe CT scans (A, B) of the L5/S1 segment reveal the vertebral isthmus diastasis. The yellow arrow indicates the site of the vertebral isthmus diastasis. Sagittal (C) and axial (D) T2 magnetic resonance imaging (MRI) showing L5/S1 disc degeneration. The disc has marked T2 signal change and loss of fluid signal seen with disc dessication and fluid loss. The disc is extending posteriorly directly (Blue arrow).\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/68d08f0ace01162bcc111cc0.png"},{"id":95172566,"identity":"ae3afad4-7f56-4a66-805c-059585cda0ef","added_by":"auto","created_at":"2025-11-05 06:39:45","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":473674,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eIntraoperative endoscopic image. Scrapping away adequately cartilaginous endplate and expose subchondral bone structure.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/f8173bab1ec1592fd578c5a4.png"},{"id":95172561,"identity":"5f130d93-4827-41dd-b65c-f61f69a7d602","added_by":"auto","created_at":"2025-11-05 06:39:45","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":297722,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eIntraoperative C-arm fluoroscopic image. A model was inserted to confirm the optimal cage size.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/0dd9cb22abc4e96c31ad1ff2.png"},{"id":95172571,"identity":"ea029349-5ace-4cae-be7e-26a1a5ff696f","added_by":"auto","created_at":"2025-11-05 06:39:45","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":251989,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eIntraoperative C-arm fluoroscopic image. Implanting allograft bone and PEE cage under C-arm fluoroscopic control. Anteroposterior X-ray showing correct implant position.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/c7135303032071355fd97857.png"},{"id":95227713,"identity":"a13f7fbc-d813-4e19-974d-43051aadf5fd","added_by":"auto","created_at":"2025-11-05 16:32:46","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":286386,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eIntraoperative C-arm fluoroscopic image. Implanting allograft bone and PEE cage under C-arm fluoroscopic supervision. Latera X-ray showing correct implant position.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/6a455b8c8cc1af55fdd7911f.png"},{"id":95172582,"identity":"12691db0-54e3-4f82-a4b3-996033db37d1","added_by":"auto","created_at":"2025-11-05 06:39:46","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":411408,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eIntraoperative endoscopic image. Checking cage position and safety of nerve roots and dural sac by full endoscopic visualization.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/aaedb37a26a244d33d3f63c9.png"},{"id":95229096,"identity":"2f465900-f2c0-4bbe-9c82-7cc6bfb15454","added_by":"auto","created_at":"2025-11-05 16:34:27","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":249369,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe picture of the four surgical incisions approximately 2 cm long.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/33d09e422ec5168bcf9d913d.png"},{"id":95172585,"identity":"fb99fc71-e997-44b3-8ddb-2323484b9908","added_by":"auto","created_at":"2025-11-05 06:39:46","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":264479,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAnteroposterior X-rays showing proper internal implant position\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/34a987bc9a482cecfdfac12b.png"},{"id":95226523,"identity":"5752ac7a-6719-4150-b336-ee3a779d200d","added_by":"auto","created_at":"2025-11-05 16:31:19","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":277442,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eLateral X-rays showing proper internal implant position\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/0bae3f334f54b878ae19685d.png"},{"id":95227496,"identity":"62362616-e6ca-4788-b472-3877f05eacbc","added_by":"auto","created_at":"2025-11-05 16:32:34","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":66179,"visible":true,"origin":"","legend":"\u003cp\u003eA nonparametric regression scatterplot smoothing curve of operative time （minutes） and the endoscopic lumbar interbody fusion case. The Graphs showing surgical time decrease with cases increase and the slope of operative time flattened after the 20-30\u003csup\u003eth \u003c/sup\u003ecase.\u003c/p\u003e","description":"","filename":"14.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/6c846b4723f924dfb5c1f95c.png"},{"id":95228721,"identity":"a1cc7ade-3d15-4f01-9c1d-90fa1f76d5b6","added_by":"auto","created_at":"2025-11-05 16:34:05","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":58090,"visible":true,"origin":"","legend":"\u003cp\u003eA nonparametric regression scatterplot smoothing curve of screw guidewires insertion time, named step 1（minutes） and the endoscopic lumbar interbody fusion case. The Graphs showing time of step 1 decrease with cases increase and the slope of operative time flattened after the 5-10\u003csup\u003eth \u003c/sup\u003ecase.\u003c/p\u003e","description":"","filename":"15.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/07282200436f93dbcfabb98d.png"},{"id":95172570,"identity":"9e67f35d-e402-4632-a4e0-0553cb1169d9","added_by":"auto","created_at":"2025-11-05 06:39:45","extension":"png","order_by":16,"title":"Figure 16","display":"","copyAsset":false,"role":"figure","size":60692,"visible":true,"origin":"","legend":"\u003cp\u003eA nonparametric regression scatterplot smoothing curve of decompression of dura sac and nerve root time, named step 2（minutes） and the endoscopic lumbar interbody fusion case. The Graphs showing time of step 2 decrease with cases increase and the slope of operative time flattened after the 20-30\u003csup\u003eth \u003c/sup\u003ecase.\u003c/p\u003e","description":"","filename":"16.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/3d2e373ae8b2caad7dd450c6.png"},{"id":95226439,"identity":"89f94078-6443-4da1-bd68-4e5fae862ad0","added_by":"auto","created_at":"2025-11-05 16:31:07","extension":"png","order_by":17,"title":"Figure 17","display":"","copyAsset":false,"role":"figure","size":62703,"visible":true,"origin":"","legend":"\u003cp\u003eA nonparametric regression scatterplot smoothing curve of endplate preparation and cage implantation time, named step 3（minutes） and the endoscopic lumbar interbody fusion case. The Graphs showing time of step 3 decrease with cases increase and reach the plateau stage at the 30-40\u003csup\u003eth \u003c/sup\u003ecase.\u003c/p\u003e","description":"","filename":"17.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/07c71a1963baa99cd1276daf.png"},{"id":95172588,"identity":"6d469884-7779-4a13-87cb-4c2c7d844b05","added_by":"auto","created_at":"2025-11-05 06:39:46","extension":"png","order_by":18,"title":"Figure 18","display":"","copyAsset":false,"role":"figure","size":62232,"visible":true,"origin":"","legend":"\u003cp\u003eA nonparametric regression scatterplot smoothing curve of percutaneous pedicle screws installation time, named step 4（minutes） and the endoscopic lumbar interbody fusion case. The Graphs showing time of step 4 decrease with cases increase and reach the plateau stage at the 10-20\u003csup\u003eth \u003c/sup\u003ecase\u003c/p\u003e","description":"","filename":"18.png","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/85b290571dcc138589e3bcaa.png"},{"id":95230713,"identity":"c1eace07-3824-4d05-9a22-b55eb9220279","added_by":"auto","created_at":"2025-11-05 16:38:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5803015,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7630072/v1/cb84ee8f-0cbf-4e41-a18e-4331da59a502.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Special learning curves and clinical outcome of full-endoscopic lumbar interbody fusion","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eDegenerative lumbar spinal disease is one kind of common disease, often leading to neurogenic claudication and radiculopathy. In the case of ineffective conservative treatments, including medication, injections, and physical therapy, surgical treatment is then indicated.\u003c/p\u003e\u003cp\u003eThe minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) procedures have been accept and widely favorable for many applications by spinal surgeons in the treatment of lumbar spondylolisthesis since 2002\u003csup\u003e[1,2]\u003c/sup\u003e.Though it has many virtues, such as durable clinical efficacy and satisfying fusion rates with less postoperative pain, early ambulation, reducing incidence of complications, MIS-TLIF technique still needs to use retractors which may lead to muscle injury and related postoperative paravertebral muscles dysfunction\u003csup\u003e[3]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eIn recent years, spine surgeons have developed more advanced minimally invasive techniques. Among them, the most prominent is the application of endoscopic-assisted spine surgery\u003csup\u003e[4]\u003c/sup\u003e. With advances in endoscopic facility and surgical technique, spinal surgeries are undergoing a rapid technological revolution for patients suffering from lumbar degenerative diseases. As a minimally invasive surgery, the newly reported technique has been recognized as safe and effective for its clear visualization and less damage as most surgical procedures are carried out within a rigid rod-shaped endoscope, which combines the working channel with lighting, video camera and irrigation system\u003csup\u003e[5]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eNevertheless, as a new technology, percutaneous endoscopic lumbar interbody fusion(PE-LIF) remains to be a challenging task. Surgeons still require extremely familiarity with the anatomical structure and skilled hand-eye cooperation ability under endoscope\u003csup\u003e[6]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eIn recent years, some researchers have reported the special learning curves of TLIF, MIS-TLIF, and OLIF\u003csup\u003e[7\u0026ndash;9]\u003c/sup\u003e. However, there were few reports about the learning curve of PE-LIF \u003csup\u003e[10]\u003c/sup\u003e. In the study, we tried to divide the entire surgical process into different time segments according to surgical procedures and the characteristics of each time frame to each surgical step were further studied. We also reported the initial clinical results to provide experience of the safety, accuracy, and efficiency of PE-LIF directly.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cp\u003eData for consecutive patients with single-segment lumbar spondylolisthesis or lumbar spinal stenosis who had undergone PE-LIF with percutaneous pedicle screw fixation from January 2022 to September 2023 were retrospectively collected. These patients were enrolled for suffering from persisting lower back pain or claudication after 4 weeks of conservative treatments at least. ALL patients were diagnosed by two senior attending doctors based on combinations of clinical manifestation and imaging evidence including X-ray, computed tomography (CT), and magnetic resonance imaging (MRI)\u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. All surgeries were performed by two deputy chief physicians. The clinical demographic and radiographic characteristics of the patients are shown in Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\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\u003ePatient demographic characteristics(n\u0026thinsp;=\u0026thinsp;40).\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\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\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\u003eValue\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge (years, mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e53.48\u0026thinsp;\u0026plusmn;\u0026thinsp;7.81\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGender (female)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e17(42.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLevels (n\u0026thinsp;=\u0026thinsp;40)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eL3/4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e6 (15.0%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eL4/5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14(35.0%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eL5/S1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e20 (50.0%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIncidence of comorbidities\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHypertension\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e13 (32.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDiabetes mellitus\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8(20.0%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCoronary artery disease\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (7.5%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRespiratory diseases\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1 (2.5%)\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\u003e14.01\u0026thinsp;\u0026plusmn;\u0026thinsp;2.35\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBody mass index (kg/m2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e24.93\u0026thinsp;\u0026plusmn;\u0026thinsp;3.17\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"2\"\u003eNormally distributed variables are presented as the means\u0026thinsp;\u0026plusmn;\u0026thinsp;SD; non-normal continuous variables are presented as the medians (range); categorical variables are presented as frequencies (%).\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe inclusion criteria were defined as follows: (1) discogenic low back pain, (2) single segmental degenerative lumbar stenosis, (3) degenerative or isthmic spondylolisthesis (grade I/II, according to the Meyerding standard), (4) degenerative lumbar spinal instability requiring stability and fusion, (5) only unilateral decompression and bone graft fusion.\u003c/p\u003e\u003cp\u003eThe exclusion criteria were (1) accompanied by congenital spinal deformity, (2) previous lumbar fusion surgery, (3) a history of vertebral fracture, spinal tumor or infection, (4) Inability to tolerate PE-LIF surgery for other reasons.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSurgical Technique.\u003c/b\u003e\u003c/p\u003e\u003cp\u003eA Delta Endoscopic System (Joimax GmbH, Karlsruhe, Germany) was used for all cases in our study. Under general anesthesia, the patient was positioned prone on a radiolucent table with abdomen suspended to lower abdominal pressure and therefore to reduce operative field bleeding. The entire surgical procedure was divided into four segments in chronological order.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStep 1 Screw guidewires insertion\u003c/h2\u003e\u003cp\u003eInitially, the operation puncture angle and projection points for screw insertion on the skin was designed and confirmed under the guidance of the C-arm. A horizontal incision of about 1.5 cm in length was made above the corresponding segment with blade. Through the surrounding tissue and fascia, the spinal puncture needles were inserted and placed in a sequence. After confirmation by the view of the C-arm, the puncture needle was gradually replaced by a guidewire.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eStep 2 Decompression of dura sac and nerve root\u003c/h3\u003e\n\u003cp\u003eThe skin entry point of percutaneous endoscope was located at the same point of the inferior vertebral pedicle screw guidewires. After guidewire/rod replacement and graded tissue dilations, an endoscopic system with an outer diameter of 10mm, an inner diameter of 6mm, was connected and placed into the working cannula. The articular processes of operative segment and ligamentum flavum were exposed, and the inferior articular process and partial lamina of upper vertebrae were removed with visualizing trephine under Delta Endoscopic System supervision. Moreover, the part superior articular process (SAP) of the lower vertebrae was also cut off to expose the Kambin triangle. Afterwards the dura sac and transverse nerve root were revealed by excision of the ligamentum flavum and hyperplastic bone. Meanwhile, the ipsilateral nerve root decompression was carried out by the cannula direction modulation.\u003c/p\u003e\n\u003ch3\u003eStep 3 Endplate preparation and cage implantation\u003c/h3\u003e\n\u003cp\u003eThe resection of the intervertebral disc was performed under endoscopic visualization \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. Under the monitoring of C-arm, discectomy and endplate decortication was underwent with the instruments, such as raspatories, pituitary rongeurs, and curettes of different sizes. Model cages of varying sized height and length were implanted through the cannula under the C-arm fluoroscopic monitoring \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. Once confirming the appropriate size, the model cage was taken out. Autogenous bone excised from SAP and allograft bone were packed into the anterior disc space and the choosing cage filled with allograft bone was inserted into the intervertebral space in appropriate depth under fluoroscopic and endoscopic visualization \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e\u003cb\u003e、9)\u003c/b\u003e. After the cage implantation, the dura sac and transverse nerve root were checked once more for inspection of satisfactory decompression under endoscopic view \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e.\u003c/p\u003e\n\u003ch3\u003eStep 4 Percutaneous pedicle screws installation\u003c/h3\u003e\n\u003cp\u003eFinally, percutaneous pedicle screws and bilateral connecting rods were then installed, and the views of screws and cage were verified under C-arm. Following thorough hemostasis and irrigation of the operative region, a drainage tube was insert and the incision was closed \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. Before discharge, all patient had a re-examination of the lumbar X-ray \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e\u003cb\u003e、13)\u003c/b\u003e.\u003c/p\u003e\n\u003ch3\u003eOutcome Measurements\u003c/h3\u003e\n\u003cp\u003eThe clinical data of the patients were recorded such as age, sex, diagnosis, surgical segment, operating time, complications, length of stay, and clinical outcomes. Visual analog scale (VAS) for back pain and leg pain, Oswestry Disability Index (ODI), and The Modified MacNab criteria were used to evaluate the before and post operative clinical results.\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eStatistical analysis was performed using SPSS version 20.0 (SPSS Inc., Chicago, IL). Data were presented as means\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. Comparisons of clinical results before and after the operations were analyzed using paired t-test. A regression analysis of operative time (y axis), and the number of cases (x axis) were conducted to characterize the learning curve of PE-LIF. Statistical significance was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\u003c/div\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003eDemographic Data\u003c/h2\u003e\u003cp\u003eA total of 42 patients were included in the study, of which 2 patients were lost to follow-up and were excluded from the scope of the study. The remaining forty patients (17, female;23, male) who underwent endoscopic lumbar fusion surgery were enrolled in this retrospective study ultimately. The mean patient age was 53:48\u0026thinsp;\u0026plusmn;\u0026thinsp;7:81 years.\u003c/p\u003e\u003cp\u003eAll patients were performed single-level TLIF. The segments of surgical distribution were 6 patients in L3/4, 14 in L4/5, and 20 in L5/S1. Patient characteristics were displayed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eLearning Curve and Clinical Outcome\u003c/h2\u003e\u003cp\u003eUsing a regression locally weighted scatterplot smoothing curve, the duration of the surgery and each corresponding step decreased while the number of cases increased. Yet, the slope of whole operative time and each corresponding step flattened at quite different case number \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e18\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. The VAS score in low-back pain, leg pain and ODI score improved significantly for all patients after surgery and continued to improve throughout the entire follow-up step \u003cb\u003e(\u003c/b\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. At the 1-year follow-up, excellent modified Macnab outcomes were achieved at 26 patients, good at 13, and fair at 1.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\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\u003eComparisons of clinical data at each follow-up time point\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" 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=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eScore\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePreoperative\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1 week Postoperative\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3 Months\u003c/p\u003e\u003cp\u003epostoperative\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1 year\u003c/p\u003e\u003cp\u003epostoperative\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003efinal follow-up\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVAS of low back pain\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e6.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e3.03\u0026thinsp;\u0026plusmn;\u0026thinsp;0.61*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e2.54\u0026thinsp;\u0026plusmn;\u0026thinsp;0.59*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e\u003cp\u003e2.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.68*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e\u003cp\u003e1.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVAS of sciatica\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e6.98\u0026thinsp;\u0026plusmn;\u0026thinsp;0.77\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e2.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.69*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e1.63\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e\u003cp\u003e1.48\u0026thinsp;\u0026plusmn;\u0026thinsp;0.62*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e\u003cp\u003e1.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.62*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eODI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e50.60\u0026thinsp;\u0026plusmn;\u0026thinsp;7.46\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e22.53\u0026thinsp;\u0026plusmn;\u0026thinsp;5.16*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e17.15\u0026thinsp;\u0026plusmn;\u0026thinsp;3.05*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e\u003cp\u003e11.30\u0026thinsp;\u0026plusmn;\u0026thinsp;3.50*\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e\u003cp\u003e9.15\u0026thinsp;\u0026plusmn;\u0026thinsp;2.83*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"6\"\u003eValues were presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"6\"\u003e*Paired t-test. p\u0026thinsp;\u0026lt;\u0026thinsp;0.05, statistically significant differences.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003eComplications\u003c/h2\u003e\u003cp\u003eThe incidence rate of complications in the series was 7.5%: 1 case of cage retropulsion, 1 case of cage subsidence, 1 case of dural matter tear and no intraoperative neurovascular injury. After one month of conservative treatment such as reducing ambulation, the 2 cases of cage shifting were controlled, and the cage movements were not significantly aggravated. The patient with dural tears had no obvious exudation in the wound after the drainage tube was removed 2 days after the operation, and the patient had no discomfort such as dizziness and fever.\u003c/p\u003e\u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eIn terms of the minimally invasive TLIF surgery, the mainstream surgical procedures may fall into three groups according to the assisted surgical system used: full-endoscopic TLIF, bi-portal endoscopic TLIF and minimally invasive TILF (MIS-TLIF). Compared with the latter two, PE-LIF may demonstrate less tissue damage and achieve satisfactory postoperative clinical rehabilitation\u003csup\u003e[11]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eIn process of mini-invasive TLIF surgery, facet joint resection is a crucial step to obtain adequate exposure of the Kambin triangle which usually might not provide enough space for patients with lumbar spondylolisthesis.\u003c/p\u003e\u003cp\u003eMany spinal surgeons have attempted to perform full-endoscopic LIF surgery using posterior interlaminar or lateral transforaminal approaches. Researchers have offered careful contrast of these two techniques \u003csup\u003e[12,13]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe interlaminar approach has obvious advantages in central vertebral canal decompression, friendly overlooking visual angles, as well as the convenience to resolve some specific types of disc herniation such as huge herniation and intervertebral disc calcification\u003csup\u003e[14]\u003c/sup\u003e. However, the patients might suffer from more stretching of dura sac and transverse nerve root. Meanwhile, the posterior approach decreased the extent of the facet joints resections which may result in incomplete exposure and decompression of the exiting nerve root.\u003c/p\u003e\u003cp\u003eThe transforaminal approach, by contrast, was designed to reduce stretching of dura sac and transverse nerve root during exposure of the Kambin triangle\u003csup\u003e[15]\u003c/sup\u003e. However, this manipulation needs to open and expand the intervertebral foramen by resection of ventral articular process which might be a hazard to damage exiting nerve root\u003csup\u003e[16]\u003c/sup\u003e. In fact, the approach has always faced another challenge of incomplete decompression of contralateral lateral recess, which is determined by the anatomical characteristics.\u003c/p\u003e\u003cp\u003eWhatever the approach you choose, the ability to locate safely and quickly at the aimed lumbar facet joint would be critical to successful completement of surgery. We accomplish the endoscopic surgical procedure in a similar conventional open pattern with the first confirmation of rapid localization at the aimed lumbar facet joint with the aid of intraoperative fluoroscopy and endoscopy. A learning curve has delineated the characteristics of the whole procedure in fact. However, the proportion of time allocation and the degree of the different steps adaptation in the whole surgical process are not the same.\u003c/p\u003e\u003cp\u003eThe greatest dilemma for the spreading of endoscopic spine surgery technology is the steep learning curve. Most researchers usually select operative time and case number as Y-axis and X-axis of learning curve coordinate axis when the learning curve of PE-LIF is mentioned\u003csup\u003e[17]\u003c/sup\u003e. However, few studies have segmented the duration of surgery according to procedure and examined the corresponding changes with the increasing case numbers performed. We divided whole operation time into four steps in accordance with the operation procedures, namely guide wire placement (step1), spinal canal decompression (step 2), cage placement (step 3) and installation of pedicle screw system (step 4). From analysis of the relationship between each time steps and the corresponding number of surgical cases, we can infer that the learning curve of each procedure is characteristic.\u003c/p\u003e\u003cp\u003eNormally, PE-LIF is technically fastidious for surgeons without enough endoscopic experience and is always accompanied by a long and steep learning curve. From Figs.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e to \u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e18\u003c/span\u003e, we can find out the steepness of learning curve on behalf of each step was quite different, as was the number of cases that reached a stable platform. A trend of longer and gradual decline was on display of the learning curves along with the increasing cases numbers in steps 2 and 3. The time of step 1 (Fig.\u0026nbsp;\u003cspan refid=\"Fig16\" class=\"InternalRef\"\u003e15\u003c/span\u003e) and 4 (Fig.\u0026nbsp;\u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e18\u003c/span\u003e) reach the learning plateau (5\u0026ndash;20 cases) was relatively quick, while steps 2\u0026ndash;3 (Fig.\u0026nbsp;\u003cspan refid=\"Fig17\" class=\"InternalRef\"\u003e16\u003c/span\u003e,\u003cspan refid=\"Fig18\" class=\"InternalRef\"\u003e17\u003c/span\u003e) take more time (20\u0026ndash;40 cases) to reach. It means that the procedures of spinal canal decompression and cage implantation need more training to achieve a stable level. It could also be inferred that the process of guide wire placement(step1) and installation of pedicle screw system(step4) may be much easier to grasp for unexperienced surgeons. Therefore, quickly location, nerve decompression and dealing with the endplate might be vital for successful and rapid completion in total endoscopic lumbar fusion surgery under the endoscopic view\u003csup\u003e[18]\u003c/sup\u003e. In general, the more endoscopically experienced the surgeon is, the safer and more efficient the surgical procedure will be\u003csup\u003e[19]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eOwing to the direct endoscopic view, preparation of endplates can be visible to avoid injury to the endplate which might result in cage subsidence and failure fixation\u003csup\u003e[20]\u003c/sup\u003e. Although the meticulous processing of cartilage endplate is impressive, the efficiency is not satisfactory\u003csup\u003e[21]\u003c/sup\u003e. We have greatly accelerated the process of endplates preparation under the endoscopy by introducing endplate handling equipment used in open surgery. It turns out that the performance of regular raspatories, pituitary rongeurs, and curettes, although invisible, is still safe and efficient under the shielding protection of sheath tube.\u003c/p\u003e\u003cp\u003eThe expandable cage was designed to increase the height of intervertebral space and improve sagittal alignment in recent reports\u003csup\u003e[22][23]\u003c/sup\u003e. However, it may lead to gradual cage subsidence for elderly patients who suffered from osteoporosis and the cost of this special cage determines its limited use at last\u003csup\u003e[24][25]\u003c/sup\u003e. In our serials, we implant ordinary PLIF cages through combined removable tube into intervertebral space. The diameter of the tube determines that the maximum size of the implanted fusion cage cannot be beyond size 12. In terms of clinical results, it was observed significant improvement in VAS, ODI score and satisfactory Macnab outcomes.\u003c/p\u003e\u003cp\u003eWe are reporting on a new percutaneous endoscopic lumbar interbody fusion surgery. We segmented the duration of surgery according to procedure and figured out the learning curve of each procedure. The central challenge of this procedure is to complete endplate preparation rapidly for fusion and insert a suitable sized interbody cage through a channel lean on Kambin\u0026rsquo;s triangle\u003csup\u003e[26]\u003c/sup\u003e. We have accelerated the process of endplates preparation under the endoscopy by introducing endplate handling equipment used in open surgery which could solve the above problem. The incidence rate of complications in the series was 7.5%: 1 case of cage retropulsion, 1 case of cage subsidence, 1 case of dural matter tear and no intraoperative neurovascular injury. In this serial, it was observed significant improvement in VAS, ODI score and satisfactory Macnab outcomes. To our knowledge, the findings have not been reported previously.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAVAILABILITY OF DATA AND MATERIALS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eETHICS APPROVAL AND CONSENT TO PARTICIPATE\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study has obtained ethics approval and consent of the Ethics Committee of the People\u0026apos;s Hospital of Guangxi Zhuang Autonomous Region.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFUNDING\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA grant from the Guangxi Natural Science Foundation Project supported this work by the Guangxi science and technology department (2024GXNSFAA010303).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number:\u0026nbsp;\u003c/strong\u003enot applicable.\u003c/p\u003e\n\u003cp\u003eConflicts of Interest\u003c/p\u003e\n\u003cp\u003eA grant from the Guangxi Natural Science Foundation Project supported this work by the Guangxi science and technology department (2024GXNSFAA010303). The other authors declare that they have no conflicts of interest concerning the materials/methods used in this study or the findings described in this paper.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLin E. Y., Kuo Y. K. \u0026amp; Kang Y. N., \u0026quot;Effects of three common lumbar interbody fusion procedures for degenerative disc disease: A network meta-analysis of prospective studies,\u0026quot; \u003cem\u003eInt J Surg\u003c/em\u003e, Vol.60(2018), pp.224-230.\u003c/li\u003e\n\u003cli\u003eKim J. S., Jung B. \u0026amp; Lee S. H., \u0026quot;Instrumented Minimally Invasive Spinal-Transforaminal Lumbar Interbody Fusion (MIS-TLIF): Minimum 5-Year Follow-Up With Clinical and Radiologic Outcomes,\u0026quot; \u003cem\u003eClin Spine Surg\u003c/em\u003e, Vol.31, No.6(2018), pp.E302-E309.\u003c/li\u003e\n\u003cli\u003eAo S., Zheng W. \u0026amp; Wu J. et al., \u0026quot;Comparison of Preliminary clinical outcomes between percutaneous endoscopic and minimally invasive transforaminal lumbar interbody fusion for lumbar degenerative diseases in a tertiary hospital: Is percutaneous endoscopic procedure superior to MIS-TLIF? A prospective cohort study,\u0026quot; \u003cem\u003eInt J Surg\u003c/em\u003e, Vol.76(2020), pp.136-143.\u003c/li\u003e\n\u003cli\u003eXiaobing Z., Xingchen L. \u0026amp; Honggang Z. et al., \u0026quot;\u0026quot;U\u0026quot; route transforaminal percutaneous endoscopic thoracic discectomy as a new treatment for thoracic spinal stenosis,\u0026quot; \u003cem\u003eInt Orthop\u003c/em\u003e, Vol.43, No.4(2019), pp.825-832.\u003c/li\u003e\n\u003cli\u003eZhao X. B., Ma H. J. \u0026amp; Geng B. et al., \u0026quot;Early Clinical Evaluation of Percutaneous Full-endoscopic Transforaminal Lumbar Interbody Fusion with Pedicle Screw Insertion for Treating Degenerative Lumbar Spinal Stenosis,\u0026quot; \u003cem\u003eOrthop Surg\u003c/em\u003e, Vol.13, No.1(2021), pp.328-337.\u003c/li\u003e\n\u003cli\u003eJacquot F. \u0026amp; Gastambide D., \u0026quot;Percutaneous endoscopic transforaminal lumbar interbody fusion: is it worth it?\u0026quot; \u003cem\u003eInt Orthop\u003c/em\u003e, Vol.37, No.8(2013), pp.1507-1510.\u003c/li\u003e\n\u003cli\u003eXu Y. F., Le XF \u0026amp; Tian W. et al., \u0026quot;Computer-assisted, minimally invasive transforaminal lumbar interbody fusion: One surgeon\u0026apos;s learning curve A STROBE-compliant article,\u0026quot; \u003cem\u003eMedicine (Baltimore)\u003c/em\u003e, Vol.97, No.27(2018), p.e11423.\u003c/li\u003e\n\u003cli\u003eBrusko G. D. \u0026amp; Wang M. Y., \u0026quot;Endoscopic Lumbar Interbody Fusion,\u0026quot; \u003cem\u003eNeurosurg Clin N Am\u003c/em\u003e, Vol.31, No.1(2020), pp.17-24.\u003c/li\u003e\n\u003cli\u003eKumar A., Merrill R. K. \u0026amp; Overley S. C. et al., \u0026quot;Radiation Exposure in Minimally Invasive Transforaminal Lumbar Interbody Fusion: The Effect of the Learning Curve,\u0026quot; \u003cem\u003eInt J Spine Surg\u003c/em\u003e, Vol.13, No.1(2019), pp.39-45.\u003c/li\u003e\n\u003cli\u003eZhao T., Dai Z. \u0026amp; Zhang J. et al., \u0026quot;Determining the learning curve for percutaneous endoscopic lumbar interbody fusion for lumbar degenerative diseases,\u0026quot; \u003cem\u003eJ Orthop Surg Res\u003c/em\u003e, Vol.18, No.1(2023), p.193.\u003c/li\u003e\n\u003cli\u003eLin E. Y., Kuo Y. K. \u0026amp; Kang Y. N., \u0026quot;Effects of three common lumbar interbody fusion procedures for degenerative disc disease: A network meta-analysis of prospective studies,\u0026quot; \u003cem\u003eInt J Surg\u003c/em\u003e, Vol.60(2018), pp.224-230.\u003c/li\u003e\n\u003cli\u003eJu C. I. \u0026amp; Lee S. M., \u0026quot;Complications and Management of Endoscopic Spinal Surgery,\u0026quot; \u003cem\u003eNeurospine\u003c/em\u003e, Vol.20, No.1(2023), pp.56-77.\u003c/li\u003e\n\u003cli\u003eMacki M., Hamilton T. \u0026amp; Haddad Y. W. et al., \u0026quot;Expandable Cage Technology-Transforaminal, Anterior, and Lateral Lumbar Interbody Fusion,\u0026quot; \u003cem\u003eOper Neurosurg\u003c/em\u003e, Vol.21, No.Suppl 1(2021), pp.S69-S80.\u003c/li\u003e\n\u003cli\u003eChen Z., Wang X. \u0026amp; Cui X. et al., \u0026quot;Transforaminal Versus Interlaminar Approach of Full-Endoscopic Lumbar Discectomy Under Local Anesthesia for L5/S1 Disc Herniation: A Randomized Controlled Trial,\u0026quot; \u003cem\u003ePain Physician\u003c/em\u003e, Vol.25, No.8(2022), pp.E1191-E1198.\u003c/li\u003e\n\u003cli\u003eTakebayashi K., Oshima Y. \u0026amp; Fujita M. et al., \u0026quot;Comparison of the Interlaminar and Transforaminal Approaches for Full-endoscopic Discectomy for the Treatment of L4/5 Lumbar Disc Herniation,\u0026quot; \u003cem\u003eNeurol Med Chir (Tokyo)\u003c/em\u003e, Vol.63, No.7(2023), pp.313-320.\u003c/li\u003e\n\u003cli\u003ePhani K. S. \u0026amp; Sudhir G., \u0026quot;Minimally invasive transforaminal lumbar interbody fusion - A narrative review on the present status,\u0026quot; \u003cem\u003eJ Clin Orthop Trauma\u003c/em\u003e, Vol.22(2021), p.101592.\u003c/li\u003e\n\u003cli\u003eZhao X. B., Ma H. J. \u0026amp; Geng B. et al., \u0026quot;Early Clinical Evaluation of Percutaneous Full-endoscopic Transforaminal Lumbar Interbody Fusion with Pedicle Screw Insertion for Treating Degenerative Lumbar Spinal Stenosis,\u0026quot; \u003cem\u003eOrthop Surg\u003c/em\u003e, Vol.13, No.1(2021), pp.328-337.\u003c/li\u003e\n\u003cli\u003eZhao T., Dai Z. \u0026amp; Zhang J. et al., \u0026quot;Determining the learning curve for percutaneous endoscopic lumbar interbody fusion for lumbar degenerative diseases,\u0026quot; \u003cem\u003eJ Orthop Surg Res\u003c/em\u003e, Vol.18, No.1(2023), p.193.\u003c/li\u003e\n\u003cli\u003eWu J., Liu H. \u0026amp; Ao S. et al., \u0026quot;Percutaneous Endoscopic Lumbar Interbody Fusion: Technical Note and Preliminary Clinical Experience with 2-Year Follow-Up,\u0026quot; \u003cem\u003eBiomed Res Int\u003c/em\u003e, Vol.2018(2018), p.5806037.\u003c/li\u003e\n\u003cli\u003eHeo D. H., Lee D. C. \u0026amp; Kim H. S. et al., \u0026quot;Clinical Results and Complications of Endoscopic Lumbar Interbody Fusion for Lumbar Degenerative Disease: A Meta-Analysis,\u0026quot; \u003cem\u003eWorld Neurosurg\u003c/em\u003e, Vol.145(2021), pp.396-404.\u003c/li\u003e\n\u003cli\u003eIshihama Y., Morimoto M. \u0026amp; Tezuka F. et al., \u0026quot;Full-Endoscopic Trans-Kambin Triangle Lumbar Interbody Fusion: Surgical Technique and Nomenclature,\u0026quot; \u003cem\u003eJ Neurol Surg A Cent Eur Neurosurg\u003c/em\u003e, Vol.83, No.4(2022), pp.308-313.\u003c/li\u003e\n\u003cli\u003eLee S. B., Yoon J. \u0026amp; Park S. J. et al., \u0026quot;Expandable Cages for Lumbar Interbody Fusion: A Narrative Review,\u0026quot; \u003cem\u003eJ Clin Med\u003c/em\u003e, Vol.13, No.10(2024).\u003c/li\u003e\n\u003cli\u003eHuang C. C., Brena K. R. \u0026amp; Tabarestani T. Q. et al., \u0026quot;Minimally-invasive trans-facet lumbar interbody fusion using a dual-dimension expandable cage: preliminary results of a multi-institutional retrospective study,\u0026quot; \u003cem\u003eJ Spine Surg\u003c/em\u003e, Vol.10, No.3(2024), pp.403-415.\u003c/li\u003e\n\u003cli\u003eCalvachi-Prieto P., McAvoy M. B. \u0026amp; Cerecedo-Lopez C. D. et al., \u0026quot;Expandable Versus Static Cages in Minimally Invasive Lumbar Interbody Fusion: A Systematic Review and Meta-Analysis,\u0026quot; \u003cem\u003eWorld Neurosurg\u003c/em\u003e, Vol.151(2021), pp.e607-e614.\u003c/li\u003e\n\u003cli\u003eSubramanian T., Merrill R. K. \u0026amp; Shahi P. et al., \u0026quot;Predictors of Subsidence and its Clinical Impact After Expandable Cage Insertion in Minimally Invasive Transforaminal Interbody Fusion,\u0026quot; \u003cem\u003eSpine (Phila Pa 1976)\u003c/em\u003e, Vol.48, No.23(2023), pp.1670-1678.\u003c/li\u003e\n\u003cli\u003ePholprajug P., Kotheeranurak V. \u0026amp; Liu Y. et al., \u0026quot;The Endoscopic Lumbar Interbody Fusion: A Narrative Review, and Future Perspective,\u0026quot; \u003cem\u003eNeurospine\u003c/em\u003e, Vol.20, No.4(2023), pp.1224-1245.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"neurosurgical-review","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nrev","sideBox":"Learn more about [Neurosurgical Review](https://www.springer.com/journal/10143)","snPcode":"10143","submissionUrl":"https://submission.nature.com/new-submission/10143/3","title":"Neurosurgical Review","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7630072/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7630072/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eIn recent years, some researchers have reported the learning curves of TLIF, MIS-TLIF, and OLIF. However, there were few reports about the learning curve of PE-LIF.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eData for consecutive patients with single-segment lumbar spondylolisthesis or lumbar spinal stenosis who had undergone PE-LIF with percutaneous pedicle screw fixation from January 2022 to September 2023 were retrospectively collected. We tried to divide the entire surgical process into different time segments according to surgical steps and the learning curves of each time frame were plotted out and further studied. We also reported the initial clinical results to provide experience of the safety, accuracy, and efficiency of PE-LIF directly.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eA total of 42 patients was included in the study, of which 2 patients were lost to follow-up and were excluded from the scope of the study. The duration of the surgery and each corresponding step decreased while the number of cases increased. Yet, the slope of whole operative time and each corresponding step flattened at quite different case numbers. The VAS score in low-back pain, leg pain and ODI score improved significantly for all patients after surgery and continued to improve throughout the entire follow-up. At the 1-year follow-up, excellent modified Macnab outcomes were achieved at 26 patients, good at 13, and fair at 1. The incidence rate of complications in the series was 7.5%: 1 case of cage retropulsion, 1 case of cage subsidence, 1 case of dural matter tear and no intraoperative neurovascular injury.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eIt is technically feasible and safe to implant an interbody fusion cage device directly through an endoscopic working cannula. It may be accelerated the process of endplates preparation under the endoscopy by introducing endplate handling equipment used in open surgery.\u003c/p\u003e","manuscriptTitle":"Special learning curves and clinical outcome of full-endoscopic lumbar interbody fusion","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-05 06:39:40","doi":"10.21203/rs.3.rs-7630072/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-01T00:47:12+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-31T14:18:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"111439663794044220472130490091600313552","date":"2026-03-22T03:31:42+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-10T20:43:01+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"161619542244249510828787703680418738236","date":"2025-10-23T22:38:38+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-23T22:30:23+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-20T20:22:54+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-18T16:46:29+00:00","index":"","fulltext":""},{"type":"submitted","content":"Neurosurgical Review","date":"2025-09-16T11:46:05+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"neurosurgical-review","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nrev","sideBox":"Learn more about [Neurosurgical Review](https://www.springer.com/journal/10143)","snPcode":"10143","submissionUrl":"https://submission.nature.com/new-submission/10143/3","title":"Neurosurgical Review","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"14d7b767-2cfc-417e-81d4-0cf5c5961790","owner":[],"postedDate":"November 5th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-22T20:08:11+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-05 06:39:40","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7630072","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7630072","identity":"rs-7630072","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}