Impact of Arthroscopic Experience on the Learning Curve in Interlaminar Endoscopic Lumbar Discectomy: A Single-Center Prospective Cohort Study of 240 Patients

Impact of Arthroscopic Experience on the Learning Curve in Interlaminar Endoscopic Lumbar Discectomy: A Single-Center Prospective Cohort Study of 240 Patients | 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 Impact of Arthroscopic Experience on the Learning Curve in Interlaminar Endoscopic Lumbar Discectomy: A Single-Center Prospective Cohort Study of 240 Patients Tomasz Sienkiel, Marcin Gąska, Przemysław Koszyk, Ewa Lipik, Barbara Jasiewicz This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8099529/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Jan, 2026 Read the published version in European Spine Journal → Version 1 posted 14 You are reading this latest preprint version Abstract Study Design: Prospective single-center observational cohort study. Objectives: To evaluate whether prior arthroscopic experience shortens the learning curve in interlaminar endoscopic lumbar discectomy (IELD) and influences complication rates and patient-reported outcomes (PROs). Methods: In accordance with STROBE guidelines, 240 consecutive patients with single-level lumbar disc herniation (MSU A/B, non-calcified, symptom duration ≤ 3 months) underwent IELD between 2021 and 2023 at the University Orthopedic and Rehabilitation Hospital in Zakopane, affiliated with the Department and Clinic of Orthopedics and Rehabilitation, Collegium Medicum, Jagiellonian University. Procedures were performed by three spine surgeons with no prior endoscopic experience; one had completed > 300 shoulder arthroscopies. Operative times were analyzed using cumulative sum (CUSUM) and linear regression. Missing data were managed using last available observation. Complications were stratified by type, phase, and surgeon. Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back and leg pain were assessed preoperatively and at 3 and 12 months. Results: All surgeons demonstrated a three-phase learning curve (learning, improvement, stabilization). Technical stabilization occurred after approximately 50 cases. The arthroscopy-experienced surgeon reached improvement earlier (case 12) than others (cases 24–26). Overall complication rate was 9.2%, highest during the learning phase (up to 25%). A single postoperative epidural hematoma was confirmed on MRI and resolved conservatively. ODI and VAS improved significantly at 3 and 12 months (p < 0.001), with no between-surgeon differences at final follow-up. Conclusions: Prior arthroscopic experience facilitates early adaptation to endoscopic visualization and may reduce initial neurological risk, but long-term outcomes remain comparable among surgeons. The study confirms IELD as a safe, effective technique with a reproducible ~50-case learning curve. Level of Evidence: III Interlaminar approach Endoscopic lumbar discectomy Learning curve Arthroscopic experience CUSUM analysis Surgical education Minimally invasive spine surgery Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 10 Figure 11 Figure 12 Figure 13 Figure 21 Figure 22 1. Introduction Background Minimally invasive spine surgery has rapidly evolved over recent decades, aiming to reduce tissue trauma, accelerate recovery, and minimize perioperative complications [1]. Interlaminar endoscopic lumbar discectomy (IELD) has become an increasingly adopted technique for the treatment of lumbar disc herniation, offering outcomes comparable to conventional microscopic discectomy while providing additional advantages such as reduced soft-tissue damage, less postoperative pain, and faster return to daily activities [2–6]. Although IELD is clinically effective, its adoption is challenged by a pronounced learning curve, largely attributable to differences in visualization, instrumentation, and operative technique compared with open or microscopic approaches [7,8]. Surgical proficiency in endoscopic procedures depends not only on case volume but also on transferable psychomotor abilities, including hand–eye coordination, triangulation within a confined space, and navigation in a two-dimensional endoscopic environment [9,10]. These competencies closely parallel those required in arthroscopic surgery, where surgeons routinely operate under indirect visualization and continuous fluid irrigation [11,12]. Arthroscopy and endoscopic spine surgery share several fundamental principles, including limited working space, two-dimensional optics, and the need for precise bimanual coordination. Therefore, prior arthroscopic experience may facilitate adaptation to endoscopic spinal procedures by reducing the time required to develop depth perception, spatial orientation, and endoscopic dexterity [13,14]. Despite these theoretical similarities, the relationship between arthroscopic experience and the learning process in endoscopic spine surgery has not been systematically evaluated. Previous studies on the IELD learning curve have primarily focused on the number of cases required for proficiency or complication reduction, but none have directly examined the impact of prior arthroscopic training [15–18]. Objective This prospective single-center cohort study aimed to analyze and compare the learning curves of three surgeons initiating IELD, one of whom had extensive prior arthroscopic experience. We evaluated operative efficiency, complication rates, and patient-reported outcomes to determine whether arthroscopic skills facilitate adaptation to endoscopic spine surgery. Hypothesis We hypothesized that prior arthroscopic experience would shorten the IELD learning curve and reduce early-phase complications, while long-term patient-reported outcomes would remain consistent across surgeons. To minimize interindividual variability, all surgeons underwent standardized endoscopic training and operated under identical institutional protocols in accordance with the STROBE reporting guidelines [19]. 2. Materials and Methods Study Design This was a prospective, single-center observational cohort study evaluating the learning curve in interlaminar endoscopic lumbar discectomy (IELD) according to the AOSpine working-channel endoscopy nomenclature [ 15 ]. The primary objective was to assess whether prior arthroscopic experience influences operative efficiency, complication rates, and patient-reported outcomes. The study adhered to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement [ 19 ]. Patient Population Between January 2021 and December 2023, a total of 240 consecutive patients underwent single-level IELD for lumbar disc herniation at a university orthopedic and rehabilitation hospital (single center) affiliated with a medical school. Patients were assigned consecutively to three endoscopy-naïve spine surgeons (A, B, and C) based on operating room availability. Surgeon A operated on 90 patients, while Surgeons B and C each treated 75 patients. One surgeon (B) had prior experience with more than 300 shoulder arthroscopies. All procedures were performed independently, without mentoring or technical assistance. To minimize interindividual and procedural bias, all surgeries were carried out in a single operating suite with identical equipment, anesthesia team, and nursing staff under a unified perioperative protocol. Inclusion and Exclusion Criteria Inclusion criteria were: • Radicular pain refractory to ≥ 4 weeks of conservative therapy; • Neurological deficit (sensory or motor) due to nerve root compression; • MRI-confirmed single-level lumbar disc herniation; • Symptom duration ≤ 3 months; • Single-level disc herniation at L4/L5 or L5/S1 (MSU zones A/B on axial T2-weighted MRI); • Written informed consent for surgery and study participation. Exclusion criteria included: • Previous lumbar spine surgery; • Foraminal or extraforaminal disc herniations; • Calcified or migrated disc fragments beyond endoscopic reach; • Spondylolisthesis or significant lumbar instability; • Severe lumbar spinal stenosis. Foraminal herniations were managed using the transforaminal approach and were therefore excluded [ 14 ]. Surgeon Characteristics and Training All three surgeons had at least five years of experience in lumbar spine surgery but no previous endoscopic experience. Each completed both basic and advanced endoscopic lumbar discectomy training at the dedicated center in Knittlingen, Germany, before initiating clinical practice. Surgeon A : No prior arthroscopy or endoscopic experience; extensive background in open spine surgery. Surgeon B : >300 prior shoulder arthroscopies; no prior endoscopic spine experience. Surgeon C : No prior arthroscopy or endoscopic experience. To ensure standardization, the same endoscopic system (Vertebris, Richard Wolf) and bipolar RF device were used throughout the study. Surgical Technique All procedures were performed under general anesthesia following the interlaminar endoscopic discectomy technique described by Ruetten et al. [ 10 ]. A 7-mm transverse incision was made, and sequential dilators were inserted to position the working sheath at the medial border of the facet joint. After identification of the ligamentum flavum, it was split to expose the herniated fragment, which was then excised under direct endoscopic vision until decompression of the affected nerve root was achieved. Adequacy of decompression was confirmed by visualization of free dural pulsation under continuous saline irrigation. The incision was closed with a single subcutaneous suture. Postoperative Management Postoperative care included non-steroidal anti-inflammatory medication, vitamin B supplementation, and a soft lumbar brace for three weeks. Routine postoperative MRI was not performed. Imaging follow-up was reserved for patients with clinical deterioration, new or persistent radicular pain, or suspected recurrence. Postoperative MRI was selectively obtained in 24 patients (10.0%) , primarily within the first four postoperative weeks. Among these, one case of epidural hematoma was confirmed radiologically and managed conservatively without surgical intervention. The remaining twenty-three scans demonstrated either residual edema or postoperative changes without compressive pathology. Data Collection and Follow-up Follow-up examinations were performed at the outpatient spine clinic at 3 and 12 months postoperatively. Follow-up data were available for 236 of 240 patients (98.3%). Missing ODI or VAS values in four cases were imputed using the last available observation method. No patient was lost to follow-up. Outcome Measures Patient-reported outcomes included the Oswestry Disability Index (ODI) [ 16 ] and Visual Analog Scale (VAS) scores for back and leg pain, recorded preoperatively and at 3 and 12 months. Operative time, intraoperative events, and complications were prospectively documented. Complications were classified as neurological (nerve root injury, dural tear), recurrence, or minor (hematoma, infection, perineural fibrosis). A postoperative epidural hematoma was confirmed radiologically on MRI when clinically suspected and treated conservatively. Sample Size and Statistical Analysis No formal sample size calculation was performed, as all consecutive eligible patients treated during the study period were included. The total cohort size (n = 240) exceeded the minimum required for robust CUSUM analysis, as suggested by previous studies [ 16 , 17 ]. Learning curve assessment was performed using cumulative sum (CUSUM) analysis and linear regression. The CUSUM statistic was defined as: CUSUM_i = Σ_{j = 1..i} (X_j − µ) where Xj​ represents the operative time for each procedure and µ denotes the mean operative time for the entire cohort. Stabilization was defined as three consecutive cases within ± 10% of each surgeon’s mean operative time. Continuous variables (ODI, VAS) were analyzed using one-way ANOVA or Kruskal–Wallis tests, as appropriate. Complication rates were compared using Fisher’s exact or chi-square tests. All analyses were performed with SPSS Statistics v26 (IBM Corp., Armonk, NY, USA), and significance was set at p < 0.05 (two-tailed). 3. Results 3.1. Learning Curve of Surgeon A Figure 1. Learning curve for Surgeon A. Initial improvement was observed at case 24, with stabilization at case 49. Abbreviations: IELD – Interlaminar Endoscopic Lumbar Discectomy; CUSUM – Cumulative Sum. Figure 2. CUSUM analysis for Surgeon A. Progressive reduction in operative time following case 24. Abbreviations: CUSUM – Cumulative Sum; IELD – Interlaminar Endoscopic Lumbar Discectomy. 3.2. Learning Curve of Surgeon B Figure 3. Learning curve for Surgeon B. Initial improvement occurred at case 12, with stabilization achieved at case 49. Abbreviations: IELD – Interlaminar Endoscopic Lumbar Discectomy; CUSUM – Cumulative Sum. Figure 4. CUSUM analysis for Surgeon B. Rapid decline in operative time after case 12. Abbreviations: CUSUM – Cumulative Sum; IELD – Interlaminar Endoscopic Lumbar Discectomy. 3.3. Learning Curve of Surgeon C Figure 5. Learning curve for Surgeon C. Initial improvement occurred at case 26, followed by stabilization at case 50. Abbreviations: IELD – Interlaminar Endoscopic Lumbar Discectomy; CUSUM – Cumulative Sum. Figure 6. CUSUM analysis for Surgeon C. Steady reduction in operative time after case 26. Abbreviations: CUSUM – Cumulative Sum; IELD – Interlaminar Endoscopic Lumbar Discectomy. 3.4. Baseline Characteristics Baseline characteristics of the study population are summarized in Table 1. Demographic and preoperative clinical variables, including age, sex, BMI, symptom duration, and operated level, were comparable across surgeon groups (p = 0.62). Table 1. Baseline characteristics of study population Variable Surgeon A (n=90) Surgeon B (n=75) Surgeon C (n=75) p-value Age (years, mean ± SD) 42.3 ± 9.8 43.1 ± 10.6 41.2 ± 10.5 0.71 Female (%) 44.4 42.7 46.7 0.88 BMI (kg/m², mean ± SD) 26.2 ± 3.8 25.8 ± 4.0 26.1 ± 3.9 0.92 Symptom duration (weeks) 11.7 ± 2.3 12.1 ± 2.1 11.9 ± 2.5 0.84 Level L4/L5 : L5/S1 28 : 62 20 : 55 18 : 57 0.63 Legend: Baseline demographic and preoperative clinical data of patients undergoing interlaminar endoscopic lumbar discectomy (IELD), stratified by surgeon. No statistically significant differences were observed between groups (p = 0.62). Abbreviations: BMI – Body Mass Index; ODI – Oswestry Disability Index; VAS – Visual Analog Scale; IELD – Interlaminar Endoscopic Lumbar Discectomy. 3.5. Learning Curve Analysis All three surgeons demonstrated progressive improvement in operative efficiency. Initial performance improvement was observed at case 24 for Surgeon A, case 12 for Surgeon B, and case 26 for Surgeon C. Stabilization occurred between the 49th and 53rd case. Table 2. Linear regression models for operative time Surgeon Regression equation Slope (min/case) R² (Model fit) Description A y = –0.28x + 69.17 –0.28 0.23 Gradual improvement B y = –0.43x + 74.89 –0.43 0.21 Faster reduction C y = –0.62x + 83.07 –0.62 0.36 Most dynamic improvement Legend: Linear regression parameters illustrating the relationship between operative time and case number for each surgeon. Negative slope indicates progressive improvement in efficiency. Abbreviations: CUSUM – Cumulative Sum; R² – Coefficient of determination; min – minutes. Operative time decreased progressively with experience in all groups, showing a negative correlation between operative time and case number. Plateau in operative efficiency was reached after approximately 50 cases across all surgeons. 3.6. CUSUM Analysis CUSUM curves for all surgeons initially trended upward, reflecting longer operative times during the early learning phase. The inflection point corresponded to performance improvement: case 24 for Surgeon A, 12 for Surgeon B, and 26 for Surgeon C. Following these peaks, operative times decreased consistently, with all curves plateauing after case 50. Mean operative times during the stabilization phase were 39.8 ± 17.3 min (A), 39.3 ± 12.8 min (B), and 45.6 ± 16.6 min (C). 3.7. Clinical Outcomes Across the entire cohort, ODI and VAS scores improved significantly from baseline to 12 months (all p < 0.001). Mean improvement at 12 months was –20.6 points for ODI, –5.8 for VAS-back, and –6.1 for VAS-leg. When stratified by surgeon and learning phase, all groups demonstrated similar improvements without inter-surgeon differences (Table 3). Table 3. Clinical outcome measures (ODI and VAS at baseline, 3 and 12 months) Time Point ODI (Mean ± SD) VAS Back (Mean ± SD) VAS Leg (Mean ± SD) p-value (vs baseline) Preoperative 33.4 ± 7.1 7.32 ± 1.54 7.45 ± 1.60 <0.001 3-month follow-up 12.2 ± 7.8 2.70 ± 1.89 2.62 ± 2.39 <0.001 12-month follow-up 6.8 ± 6.8 1.41 ± 1.55 1.32 ± 1.92 <0.001 Legend: Functional outcomes at baseline and follow-up showing significant improvement across all time points (p < 0.001). No significant differences between surgeons were observed. Abbreviations: ODI – Oswestry Disability Index; VAS – Visual Analog Scale. Figure 7. Patient-reported outcomes stratified by surgeon and learning phase: (A) Oswestry Disability Index (ODI) at 12 months; (B) Visual Analog Scale (VAS) for back pain at 12 months; (C) Visual Analog Scale (VAS) for leg pain at 12 months. All surgeons demonstrated marked improvement already during the learning phase, with stable results across the improvement and stabilization phases. No significant differences were found among surgeons (all p > 0.2). Abbreviations: ODI – Oswestry Disability Index; VAS – Visual Analog Scale; IELD – Interlaminar Endoscopic Lumbar Discectomy. 3.8. Complications A total of 22 complications were recorded, corresponding to an overall rate of 9.2% . Complications occurred most frequently during the initial learning phase (16–25%) compared with the improvement (5–13%) and stabilization phases (2–4%) ( OR 6.7, 95% CI 1.1–38.9; p = 0.048) (Table 4). Neurological complications, including four transient nerve root injuries and three dural tears , were observed exclusively during the learning phase ( p = 0.024). Recurrent disc herniations ( n = 15, 6.3%) were distributed across all phases without significant association with surgeon experience ( p = 0.62). Postoperative MRI was performed in 24 patients (10%) who presented with persistent or recurrent postoperative pain. Minor events included intraoperative foreign body migration, postoperative hematoma ( n = 6), and perineural fibrosis ( n = 5). Postoperative hematomas were identified on MRI in symptomatic patients and were managed conservatively with good outcomes—only transient pain symptoms were observed, without neurological sequelae. All minor events resolved spontaneously and were therefore not included in the overall complication rate. Table 4. Complications stratified by surgeon, phase, and type Surgeon Phase Nerve Root Injury Dural Tear Recurrence Total Complications Rate (%) A Learning 1 1 2 4 16.7 A Improvement 0 0 2 2 8.0 A Stabilization 0 0 1 1 2.4 B Learning 2 0 1 3 25.0 B Improvement 0 0 2 2 5.6 B Stabilization 0 0 1 1 3.7 C Learning 1 2 2 5 19.2 C Improvement 0 0 3 3 12.5 C Stabilization 0 0 1 1 3.8 Total — 4 3 15 22 9.2 Legend: Distribution of perioperative complications by learning phase and surgeon. Complications were most frequent during the initial learning phase and decreased with experience. Abbreviations: IELD – Interlaminar Endoscopic Lumbar Discectomy; Rate – percentage of complications within each learning phase; OR – Odds Ratio; CI – Confidence Interval. 3.9. Between-Surgeon Comparisons Functional outcomes at 12 months (ODI, VAS) and complication rates did not differ significantly among surgeons (all p > 0.2). Recurrences occurred most frequently within 2–4 months postoperatively and were often related to premature return to physical work. Early technical issues such as instrument migration resolved with increasing experience. Table 5. Between-surgeon comparisons of outcomes Outcome Surgeon A (n=90) Surgeon B (n=75) Surgeon C (n=75) p-value (ANOVA) p-value (Kruskal–Wallis) ODI preoperative 33.0 34.9 34.0 0.895 0.890 ODI at 12 months 6.9 5.3 7.2 0.240 0.225 VAS back preoperative 7.5 7.3 7.1 0.722 0.608 VAS back at 12 months 1.5 1.1 1.3 0.490 0.543 VAS leg preoperative 7.4 7.7 7.2 0.894 0.950 VAS leg at 12 months 0.9 1.0 1.1 0.779 0.804 Complication rate (%) 7.8 8.0 12.0 – Fisher/Chi² p = 0.62 Legend: Comparison of patient-reported outcomes and complication rates between surgeons at baseline and 12-month follow-up. No statistically significant differences were found among surgeons (all p > 0.2). Abbreviations: ODI – Oswestry Disability Index; VAS – Visual Analog Scale; CUSUM – Cumulative Sum; Rate – percentage of complications in phase. 4. Discussion This prospective cohort study evaluated the effect of prior arthroscopic experience on the learning curve in interlaminar endoscopic lumbar discectomy (IELD). Across 240 consecutive cases performed by three surgeons, the learning plateau was reached between the 49th and 53rd procedure, consistent with previously reported thresholds for technical proficiency in endoscopic lumbar discectomy [7–10]. Although the surgeon with prior arthroscopic experience achieved stabilization earlier, this did not translate into superior long-term functional outcomes or lower overall complication rates. These findings suggest that arthroscopic skills facilitate early procedural adaptation but do not independently influence final clinical recovery. 4.1. Comparison with Previous Literature Previous studies investigating the learning curve in endoscopic lumbar discectomy have demonstrated wide variability in the number of cases required to achieve proficiency. Ruetten et al. [10] reported that 40–60 cases were typically required for stabilization, while Lee et al. [12] found plateau points between 30 and 55 cases based on operative time and complication reduction. Our results, showing stabilization after approximately 50 cases, are therefore consistent with these benchmarks and reinforce the reproducibility of the learning pattern across different institutions. CUSUM analysis has been widely used to quantify technical progression in endoscopic spine surgery. Huang et al. [18] and Kim et al. [20] described steep declines in operative time within the first 20–40 cases, followed by plateauing performance — closely mirroring our findings. The present study adds a novel perspective by prospectively comparing surgeons with and without arthroscopic experience, providing direct evidence that prior arthroscopy training may accelerate early technical adaptation, particularly during the transition from microscopic to endoscopic visualization. Arthroscopic surgery involves operating in a fluid-filled, two-dimensional field under indirect visualization, requiring precise bimanual coordination and triangulation. These psychomotor skills are analogous to those employed in endoscopic spine surgery [21–23]. This likely explains the earlier improvement phase observed in the arthroscopy-experienced surgeon (case 12 versus 24–26 in the others). 4.2. Functional Outcomes All surgeons achieved significant improvements in ODI and VAS scores, consistent with previous IELD series [2,3,5,6]. In a meta-analysis by Sairyo et al. [8], mean ODI reduction after endoscopic lumbar discectomy ranged from 20 to 25 points, and VAS-leg improvement from 5 to 6 points — values nearly identical to those observed in our cohort (ΔODI = 26.6, ΔVAS-leg = 6.1). These results confirm that patients benefit from the minimally invasive nature of IELD even during the early learning phase, provided that case selection and procedural protocols are standardized. No association was observed between prior arthroscopic experience and long-term patient-reported outcomes, which remained uniformly favorable across surgeons. This indicates that while arthroscopic experience may accelerate early technical mastery, ultimate clinical recovery depends primarily on surgical indication, procedural precision, and structured postoperative care rather than prior training background. 4.3. Complications and Safety Profile The overall complication rate of 9.2% observed in this study aligns with previously reported values (5–12%) [7, 10, 13]. Most complications occurred during the early learning phase, particularly transient nerve root irritation and dural tears, which decreased substantially after stabilization. This trend mirrors prior CUSUM-based analyses showing that early-phase complications can be up to three times more frequent than in later stages [9, 14]. A single postoperative epidural hematoma was confirmed by MRI and managed conservatively with complete resolution and no neurological sequelae. Selective postoperative MRI was performed in a small subset of symptomatic patients with persistent or recurrent pain, ensuring adequate evaluation of clinically significant complications while avoiding unnecessary routine imaging. The recurrence rate of lumbar disc herniation was 6.3%, consistent with the 5–8% reported in the literature [3, 6, 13]. Most recurrences occurred within the first 3–4 months after surgery and were associated with premature return to physically demanding work. These findings emphasize the importance of structured postoperative rehabilitation and patient education following IELD. 4.4. Impact of Arthroscopic Experience on Learning Curve The surgeon with prior arthroscopic experience entered the improvement phase earlier (case 12 vs. 24–26 for the other surgeons), indicating a faster initial adaptation to endoscopic instrumentation and visualization. This finding supports the concept that psychomotor and spatial orientation skills acquired through arthroscopy—such as triangulation, camera control, and bimanual coordination—are transferable to endoscopic spine surgery. Such familiarity likely enhances confidence and dexterity during the early learning phase, reducing hesitation and technical errors when operating in a two-dimensional endoscopic environment. However, once technical stabilization was achieved, operative times, complication rates, and patient-reported outcomes converged across all surgeons. This suggests that the advantage conferred by prior arthroscopic experience is confined primarily to the early stage of the learning process. As surgical exposure and experience accumulate, performance equalizes regardless of previous arthroscopic background. These observations support the inclusion of arthroscopic simulation, cadaveric dissection, or dry-lab endoscopic exercises in structured spine training curricula to accelerate skill acquisition and shorten the early learning curve in novice endoscopic surgeons. 4.5. Study Limitations This study has several limitations that should be acknowledged. First, the comparison involved only three surgeons, with one having prior arthroscopic experience. Although all surgeons had comparable backgrounds in spine surgery and completed identical endoscopic training, this small sample introduces potential operator-related bias and limits generalizability. Second, the single-center design may not fully reflect variations in institutional infrastructure, surgical culture, or case selection that could influence the learning curve. Future multicenter studies involving a larger and more diverse group of surgeons with varying arthroscopic backgrounds are warranted to confirm these findings. Third, the follow-up period of 12 months, although sufficient to evaluate short-term recovery and early recurrence, does not allow assessment of long-term sequelae such as adjacent segment degeneration or reherniation beyond one year. Finally, while the CUSUM approach offers an objective quantitative measure of operative efficiency and error reduction, it does not capture qualitative aspects of decision-making, tissue handling, or ergonomic performance that may also contribute to surgical proficiency. 4.6. Clinical Implications and Conclusions The findings of this study have direct implications for surgical education and training in minimally invasive spine procedures. Interlaminar endoscopic lumbar discectomy (IELD) requires a distinct psychomotor skill set that differs from open and microscopic techniques. Surgeons with prior arthroscopic experience may adapt more rapidly during the early learning phase due to transferable visuospatial and bimanual coordination skills. Therefore, incorporating structured exposure to arthroscopic or endoscopic simulation, cadaveric workshops, and virtual-reality–based modules into standardized training curricula may accelerate technical proficiency and reduce early-phase complications. Competency-based, modular training models similar to those used in arthroscopy and laparoscopy could improve the safety and reproducibility of endoscopic spine surgery as the field continues to expand. In conclusion, prior arthroscopic experience appears to shorten the initial learning curve in interlaminar endoscopic lumbar discectomy, facilitating faster technical adaptation without compromising safety or long-term outcomes. Once procedural stabilization is achieved, operative times, complication rates, and functional recovery become comparable among surgeons regardless of their previous arthroscopic background. These results highlight the reproducible nature of the IELD learning curve and the transferable value of arthroscopic psychomotor skills, supporting the integration of targeted simulation and structured mentorship into contemporary endoscopic spine training programs. 5. Conclusions Interlaminar endoscopic lumbar discectomy (IELD) is a safe and effective procedure characterized by a three-phase learning curve, reaching stabilization after approximately 50 cases. Prior arthroscopic experience facilitates a faster transition through the early learning phase and may reduce initial technical errors, although long-term functional outcomes and complication rates remain comparable across surgeons. These findings confirm the reproducible nature of the IELD learning curve and highlight the transferable value of arthroscopic psychomotor skills in accelerating adaptation to endoscopic techniques. Integrating arthroscopic or endoscopic simulation-based modules into structured, competency-oriented training programs may enhance surgical education and improve early procedural safety. Abbreviations BMI – Body Mass Index CI – Confidence Interval CUSUM – Cumulative Sum ESJ – European Spine Journal IELD – Interlaminar Endoscopic Lumbar Discectomy MRI – Magnetic Resonance Imaging MSU – Michigan State University Classification ODI – Oswestry Disability Index OR – Odds Ratio PROs – Patient-Reported Outcomes RF – Radiofrequency VAS – Visual Analog Scale Declarations Ethics Statement The study was conducted in accordance with the Declaration of Helsinki and was approved by the Bioethics Committee of the Jagiellonian University (Decision No. 1072.6120321.2021, dated December 15, 2021). All patients provided written informed consent prior to participation. Data Availability Statement The datasets generated and analyzed during the current study are not publicly available due to patient privacy and institutional policy but are available from the corresponding author on reasonable request. All data were collected and securely stored at the University Orthopedic and Rehabilitation Hospital in Zakopane, Department and Clinic of Orthopedics and Rehabilitation, Collegium Medicum, Jagiellonian University, Kraków, Poland. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. The study was self-funded by the authors. Conflict of Interest The authors declare that they have no conflicts of interest related to this study. Author Contributions Author A designed the study and performed the surgeries. Author B conducted the data analysis. Author C contributed to manuscript writing and literature review. All authors read and approved the final version of the manuscript. References Smith JS, Fessler RG. Paradigm changes in spine surgery: evolution of minimally invasive techniques. Eur Spine J . 2012;21(4):556–568. Ruetten S, Komp M, Merk H, Godolias G. Full-endoscopic interlaminar and transforaminal lumbar discectomy versus conventional microsurgical technique: a prospective, randomized, controlled study. Spine (Phila Pa 1976) . 2008;33(9):931–939. Choi G, Lee SH, Lokhande P, Kong BJ, Shim CS, Jung B, et al. Percutaneous endoscopic interlaminar discectomy for L5–S1 disc herniation: technique, outcome, and complications. Minim Invasive Neurosurg . 2011;54(2):81–87. Ahn Y, Lee SH, Park WM, Lee HY, Shin SW, Kang HY. Percutaneous endoscopic lumbar discectomy for recurrent disc herniation: surgical technique, outcome, and prognostic factors. J Neurosurg Spine . 2012;16(6):601–607. Komp M, Hahn P, Oezdemir S, Ruetten S. Bilateral spinal decompression of lumbar central stenosis with the full-endoscopic interlaminar technique: technique and prospective results of 163 cases. World Neurosurg . 2015;84(5):964–971. Heo DH, Quillo-Olvera J, Park CK. Complications of endoscopic lumbar surgery and strategy for prevention. World J Clin Cases . 2020;8(1):100–113. Ahn Y, Lee HY, Lee SH, Lee JH. Learning curve for percutaneous endoscopic lumbar discectomy: prospective analysis of the first 50 cases performed by a single surgeon. Spine (Phila Pa 1976) . 2013;38(6):E494–E501. Lee DY, Ahn Y, Lee SH. Percutaneous endoscopic lumbar discectomy learning curve for surgeons experienced in microscopic discectomy. Spine (Phila Pa 1976) . 2012;37(18):1543–1548. Choi KC, Kim JS, Lee DC, Park CK. Learning curve associated with complications in biportal endoscopic spinal surgery: challenges and strategies. World Neurosurg . 2019;132:e926–e932. Ruetten S, Komp M, Oezdemir S, Godolias G. Technique of transforaminal endoscopic lumbar discectomy with foraminoplasty. Eur Spine J . 2009;18(3):461–467. Barret DS, Cobb AG, Bentley G. Arthroscopic training—skills transfer from orthopaedics to endoscopy. Ann R Coll Surg Engl . 1995;77(3):173–176. Kim SJ, Choi NH, Kim H, Victoroff BN. Arthroscopic skills acquisition and transfer: comparison between orthopedic and general surgeons. Arthroscopy . 2004;20(4):375–380. Kim HS, Wu PH, Jang IT. Technical advancements in endoscopic spine surgery: navigating the learning curve. J Minim Invasive Spine Surg Tech . 2021;6(2):243–250. Heo DH, Kim JS, Park CK. Learning curve and safety of full-endoscopic lumbar surgery: cumulative summation analysis of 250 cases. World Neurosurg . 2020;138:e450–e457. Sairyo K, Higashino K, Sakai T, et al. History and evolution of endoscopic spinal surgery: learning from the past and advancing toward the future. Glob Spine J . 2022;12(1):66–75. Liu X, Yuan S, Tian W, et al. CUSUM learning curve analysis of full-endoscopic lumbar discectomy. Eur Spine J . 2020;29(8):1899–1907. Kang T, Park SY, Park JH, et al. Learning curve for interlaminar endoscopic lumbar discectomy: CUSUM analysis of 120 consecutive cases. Spine J . 2021;21(9):1522–1530. Hofstetter CP, Ahn Y, Choi G, et al. Endoscopic lumbar spine surgery: state of the art and future directions. Neurosurg Focus . 2019;46(5):E14. von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP; STROBE Initiative. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. Int J Surg . 2014;12(12):1495–1499. Telfeian AE, Choi DB, Ahn Y. Learning curve analysis of transforaminal endoscopic lumbar discectomy. World Neurosurg . 2019;128:e850–e856. Wu PH, Kim HS, Jang IT. How to master lumbar endoscopic discectomy: tips and tricks for overcoming the learning curve. Eur Spine J . 2020;29(Suppl 1):29–39. Yeung AT, Tsou PM. Posterolateral endoscopic excision for lumbar disc herniation: surgical technique, outcome, and complications. Spine (Phila Pa 1976) . 2002;27(7):722–731. Kotheeranurak V, Jitpakdee K, Kim JS. Complications and risk factors in endoscopic lumbar spine surgery: a systematic review. Glob Spine J . 2022;12(3):471–489. Kim JS, Jung B, Lee SH. Instrumentation and visualization challenges in full-endoscopic lumbar discectomy. Clin Orthop Surg . 2016;8(3):325–332. Lee CW, Yoon KJ, Ha SS. Comparison of endoscopic discectomy and microdiscectomy in lumbar disc herniation: minimum 2-year follow-up. Eur Spine J . 2015;24(5):939–946. Ahn Y. Endoscopic spine discectomy: current status and future perspectives. Asian Spine J . 2020;14(5):682–697. Wang T, Li Z, Wang Y, et al. Postoperative epidural hematoma after endoscopic lumbar surgery: incidence, risk factors, and management. World Neurosurg . 2021;149:e113–e121. Cho JY, Lee SH, Kim WC. Risk factors and management of recurrent lumbar disc herniation after percutaneous endoscopic lumbar discectomy. World Neurosurg . 2017;99:425–433. Akbary K, Kim JS, Park CW. Early postoperative outcomes and learning curve of endoscopic interlaminar lumbar discectomy. Clin Neurol Neurosurg . 2018;173:183–189. Sclafani JA, Kim CW. Complications associated with minimally invasive spine surgery. J Am Acad Orthop Surg . 2014;22(9):464–472. Heo DH, Park CK. Comparative analysis of learning curves and outcomes between interlaminar and transforaminal endoscopic discectomy. World Neurosurg . 2019;127:e748–e755. Wu PH, Jang IT, Kim HS. Transferrable arthroscopic psychomotor skills for endoscopic spine surgeons: a training perspective. J Minim Invasive Spine Surg Tech . 2022;7(1):12–19. Hofstetter CP, Ahn Y, Choi G. Minimally invasive and endoscopic approaches to the lumbar spine. Neurosurg Clin N Am . 2020;31(1):17–26. Heo DH, Kim JS. The role of competency-based training in endoscopic spine surgery. Glob Spine J . 2023;13(4):515–523. Additional Declarations No competing interests reported. Supplementary Files SupplementaryMaterialSTROBE.docx Cite Share Download PDF Status: Published Journal Publication published 28 Jan, 2026 Read the published version in European Spine Journal → Version 1 posted Editorial decision: Revision requested 17 Dec, 2025 Reviews received at journal 17 Dec, 2025 Reviewers agreed at journal 16 Dec, 2025 Reviews received at journal 16 Dec, 2025 Reviewers agreed at journal 15 Dec, 2025 Reviewers agreed at journal 15 Dec, 2025 Reviewers agreed at journal 15 Dec, 2025 Reviewers agreed at journal 14 Dec, 2025 Reviewers agreed at journal 07 Dec, 2025 Reviewers agreed at journal 04 Dec, 2025 Reviewers invited by journal 20 Nov, 2025 Editor assigned by journal 19 Nov, 2025 Submission checks completed at journal 19 Nov, 2025 First submitted to journal 12 Nov, 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-8099529","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":544143910,"identity":"6f887a38-a116-4762-bffd-3ae20b2eb8b1","order_by":0,"name":"Tomasz Sienkiel","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABC0lEQVRIiWNgGAWjYDACZgYGxgYDBhkYXw5EHHhAhBYeBjYI3xisJYGARYwNDAgtiQ0gEp8W+XbmYw9nFNjwMMg3H93w409d+vywww+BttjJ6TZg12JwmC3dcINBGtAWtrSbvW1suRtvpxkAtSQbmx3AoYWZx0zygcFhoBYesxu8DTy5G2cngLQcSNyGQ4t8M/83oJb/YC03//yRSDecnf4BrxaGwzxskhsMDoC13OZhM0iQl87BbwvQL2aSMwySeYBeSbst25ZguEE6p+BAggFuv8j3H34m2fPHTo6f+fCxm2/+1MnLz07f/OFDhZ0cLi1wwAa3F6zSgIByVHsbSFE9CkbBKBgFIwEAAGQdWSjW4GPIAAAAAElFTkSuQmCC","orcid":"","institution":"University Orthopedic and Rehabilitation Hospital","correspondingAuthor":true,"prefix":"","firstName":"Tomasz","middleName":"","lastName":"Sienkiel","suffix":""},{"id":544143911,"identity":"d5ea2abb-7eb5-45d3-a37a-6b9eaa50e4df","order_by":1,"name":"Marcin Gąska","email":"","orcid":"","institution":"University Orthopedic and Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Marcin","middleName":"","lastName":"Gąska","suffix":""},{"id":544143912,"identity":"80851f5a-ef92-4a06-b76d-328e454ab9e5","order_by":2,"name":"Przemysław Koszyk","email":"","orcid":"","institution":"University Orthopedic and Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Przemysław","middleName":"","lastName":"Koszyk","suffix":""},{"id":544143913,"identity":"ddf47185-412e-4b44-80a7-633fcb3c75d8","order_by":3,"name":"Ewa Lipik","email":"","orcid":"","institution":"University Orthopedic and Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Ewa","middleName":"","lastName":"Lipik","suffix":""},{"id":544143914,"identity":"3e6b6138-a735-4d7b-a911-6d6f8b04a3bc","order_by":4,"name":"Barbara Jasiewicz","email":"","orcid":"","institution":"University Orthopedic and Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Barbara","middleName":"","lastName":"Jasiewicz","suffix":""}],"badges":[],"createdAt":"2025-11-12 20:23:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8099529/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8099529/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00586-026-09758-8","type":"published","date":"2026-01-28T15:58:43+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":96288852,"identity":"981ac84d-4d04-4fd7-833a-465651991e49","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":889685,"visible":true,"origin":"","legend":"","description":"","filename":"FigureLegendsESJ.docx","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/3ff84940cf9de093506a6e27.docx"},{"id":96288856,"identity":"0a19e4f7-f6c6-43d8-b7a3-d5a3a890e226","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":912909,"visible":true,"origin":"","legend":"","description":"","filename":"ImpactofArthroscopicExperienceontheLearningCurveinInterlaminarEndoscopicLumbarDiscectomyASingleCenterProspectiveCohortStudyof240Patients.docx","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/71896d9dec6a2cedd8c0b488.docx"},{"id":96365191,"identity":"d27b465e-310a-4a4e-b1fe-bc277546dbc2","added_by":"auto","created_at":"2025-11-20 10:10:04","extension":"json","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7948,"visible":true,"origin":"","legend":"","description":"","filename":"ab78985d496f45e896673675d5c43114.json","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/f5affff320073d26e05317dd.json"},{"id":96366114,"identity":"208d07f6-499b-41e1-9a29-0164684ba493","added_by":"auto","created_at":"2025-11-20 10:11:12","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":18863,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterialSTROBE.docx","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/97d0d8191498ed362713bc56.docx"},{"id":96363687,"identity":"094be1be-eb67-4eba-933d-a5cb444bbfaa","added_by":"auto","created_at":"2025-11-20 10:07:44","extension":"xml","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":127988,"visible":true,"origin":"","legend":"","description":"","filename":"ab78985d496f45e896673675d5c431141enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/15b818f09edf2b450c5e37b9.xml"},{"id":96288881,"identity":"d15d8023-394d-4e3e-80aa-b1b90af83d0e","added_by":"auto","created_at":"2025-11-19 12:13:50","extension":"jpeg","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":254088,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage14.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/f59c4bf75f8bcce2623411c7.jpeg"},{"id":96288869,"identity":"cd3af8bf-4dbb-46c4-b0a9-1b8ca94beb78","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":23,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":40086,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/2d7fd0cbc8c476f53673ec44.png"},{"id":96288871,"identity":"86c3358d-2de9-4fd9-9f0e-f0416dcad1e8","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":24,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":52569,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/03184786b25d6f39f845097f.png"},{"id":96364717,"identity":"2a60e2d7-3e3c-42e7-b3e5-b86dcdedebb7","added_by":"auto","created_at":"2025-11-20 10:09:33","extension":"png","order_by":25,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":33433,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage11.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/eef3c868e4f488ac3a6c0f76.png"},{"id":96288875,"identity":"d0a0d7b1-fc93-4f64-bbb8-176c2b86144b","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":26,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":41696,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage12.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/b50fe67263c6d4440f7ee19c.png"},{"id":96288880,"identity":"87636f29-b68f-469b-849f-ff2cb5d97a3f","added_by":"auto","created_at":"2025-11-19 12:13:50","extension":"png","order_by":27,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":30824,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage13.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/01afac78f16ebe1a0d5c2879.png"},{"id":96366082,"identity":"84624e56-9812-4ee1-807f-6ef775b7cd66","added_by":"auto","created_at":"2025-11-20 10:11:10","extension":"png","order_by":28,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":46506,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage14.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/448997753ccd5e890a07eee0.png"},{"id":96365300,"identity":"9b5691a0-6938-48e3-8ff1-57e130d3fb95","added_by":"auto","created_at":"2025-11-20 10:10:14","extension":"png","order_by":29,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":30270,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/89353013d6619793fb791815.png"},{"id":96288876,"identity":"272ad5d0-5d1a-438c-93fe-d93286140e1f","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":30,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":52569,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/e9a07c1e91b6af5ca66f6a86.png"},{"id":96288878,"identity":"6fd266e5-3522-4ef4-8175-b9777fb2f6b1","added_by":"auto","created_at":"2025-11-19 12:13:50","extension":"png","order_by":31,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":33433,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/edbad3e420de290f8a2f4da7.png"},{"id":96365294,"identity":"8b7ea59d-c141-4250-9d34-cdf095d44967","added_by":"auto","created_at":"2025-11-20 10:10:14","extension":"png","order_by":32,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":41696,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/1207910f220f690b535a95d2.png"},{"id":96288885,"identity":"cef7629c-2e7f-46dd-94c9-ddd5b6126508","added_by":"auto","created_at":"2025-11-19 12:13:50","extension":"png","order_by":33,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":30824,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/15a5a9249c76e575161094ca.png"},{"id":96364420,"identity":"c4f65cd4-d786-49f9-9a26-75974a6eda8b","added_by":"auto","created_at":"2025-11-20 10:09:17","extension":"png","order_by":34,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":31498,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/c4c5f8860e1b0709c3a191f2.png"},{"id":96288884,"identity":"bfb815bc-e562-4121-a5d6-425210d1184a","added_by":"auto","created_at":"2025-11-19 12:13:50","extension":"png","order_by":35,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":40086,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/bc6abaddfe5f313b7df36e45.png"},{"id":96288883,"identity":"86a3a6db-b2a4-4682-a5cf-093604596d23","added_by":"auto","created_at":"2025-11-19 12:13:50","extension":"png","order_by":36,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":30270,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/7aaae7d108bf0fc6dac8c90e.png"},{"id":96288886,"identity":"1c410eb4-0031-4085-bd41-8e9db0f33297","added_by":"auto","created_at":"2025-11-19 12:13:50","extension":"xml","order_by":37,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":119224,"visible":true,"origin":"","legend":"","description":"","filename":"ab78985d496f45e896673675d5c431141structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/8f73f33f6d48a3ba184c2e6d.xml"},{"id":96288887,"identity":"f57c3b9b-66bf-4216-967b-9c5458c45991","added_by":"auto","created_at":"2025-11-19 12:13:50","extension":"html","order_by":38,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":142112,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/a3267df00c11dce57bf804b6.html"},{"id":96288854,"identity":"6bc5a682-2cda-4d2d-8914-b7548d076c6e","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":150008,"visible":true,"origin":"","legend":"\u003cp\u003eLearning curve for Surgeon A. Initial improvement was observed at case 24, with stabilization at case 49.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e IELD – Interlaminar Endoscopic Lumbar Discectomy; CUSUM – Cumulative Sum.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/029ee810b52ae849323c0aa8.png"},{"id":96288853,"identity":"67f688d5-48a5-4cd0-9a25-7ca916c8bd02","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":91870,"visible":true,"origin":"","legend":"\u003cp\u003eCUSUM analysis for Surgeon A. Progressive reduction in operative time following case 24.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e CUSUM – Cumulative Sum; IELD – Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/a777877d5a6b7ef975b6ffbb.png"},{"id":96364564,"identity":"5d8a437e-ecd9-439e-9a18-d4dac31afaad","added_by":"auto","created_at":"2025-11-20 10:09:25","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":165133,"visible":true,"origin":"","legend":"\u003cp\u003eLearning curve for Surgeon B. Initial improvement occurred at case 12, with stabilization achieved at case 49.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e IELD – Interlaminar Endoscopic Lumbar Discectomy; CUSUM – Cumulative Sum.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/e637f191b74eb2e4e138974f.png"},{"id":96365887,"identity":"e71d4c18-b76d-4e3b-a85b-918b02c7189b","added_by":"auto","created_at":"2025-11-20 10:10:55","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":101532,"visible":true,"origin":"","legend":"\u003cp\u003eCUSUM analysis for Surgeon B. Rapid decline in operative time after case 12.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e CUSUM – Cumulative Sum; IELD – Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/f02c25d5973be3cb32e02362.png"},{"id":96288859,"identity":"d0f0239e-85a6-4ef1-91f4-bf223d0990ed","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":159058,"visible":true,"origin":"","legend":"\u003cp\u003eLearning curve for Surgeon C. Initial improvement occurred at case 26, followed by stabilization at case 50.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e IELD – Interlaminar Endoscopic Lumbar Discectomy; CUSUM – Cumulative Sum.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/ca3b25368e6c2d8e2fbbf01d.png"},{"id":96288858,"identity":"436a7904-c01a-4324-9f6a-7db06ea227f1","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":97238,"visible":true,"origin":"","legend":"\u003cp\u003eCUSUM analysis for Surgeon C. Steady reduction in operative time after case 26.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e CUSUM – Cumulative Sum; IELD – Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/be243944605c5f1dc9a0d278.png"},{"id":96364745,"identity":"511d9ee3-3d1b-421c-b8a3-1cb5965f19f9","added_by":"auto","created_at":"2025-11-20 10:09:35","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":94213,"visible":true,"origin":"","legend":"\u003cp\u003ePatient-reported outcomes stratified by surgeon and learning phase:\u003cbr\u003e\n(A) Oswestry Disability Index (ODI) at 12 months;\u003cbr\u003e\n(B) Visual Analog Scale (VAS) for back pain at 12 months;\u003cbr\u003e\n(C) Visual Analog Scale (VAS) for leg pain at 12 months.\u003cbr\u003e\nAll surgeons demonstrated marked improvement already during the learning phase, with stable results across the improvement and stabilization phases. No significant differences were found among surgeons (all p \u0026gt; 0.2).\u003cbr\u003e\n \u003cstrong\u003eAbbreviations:\u003c/strong\u003e ODI – Oswestry Disability Index; VAS – Visual Analog Scale; IELD – Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/000cb777c5bab6ccf45f3d08.png"},{"id":96364677,"identity":"edfe1c51-cb32-479a-a2ff-7c16507be75f","added_by":"auto","created_at":"2025-11-20 10:09:32","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":165133,"visible":true,"origin":"","legend":"\u003cp\u003eLearning curve for Surgeon B. Initial improvement occurred at case 12, with stabilization achieved at case 49.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e IELD – Interlaminar Endoscopic Lumbar Discectomy; CUSUM – Cumulative Sum.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/9a3e8473f6c2f6e6f2c998d5.png"},{"id":96288864,"identity":"285d85e8-8a88-4744-9b93-39d079af7ada","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":101532,"visible":true,"origin":"","legend":"\u003cp\u003eCUSUM analysis for Surgeon B. Rapid decline in operative time after case 12.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e CUSUM – Cumulative Sum; IELD – Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/cbcf716bb2a6240eaabbdaa3.png"},{"id":96364906,"identity":"3556aab8-edc6-4c61-a43a-30b93ccc9266","added_by":"auto","created_at":"2025-11-20 10:09:47","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":159058,"visible":true,"origin":"","legend":"\u003cp\u003eLearning curve for Surgeon C. Initial improvement occurred at case 26, followed by stabilization at case 50.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e IELD – Interlaminar Endoscopic Lumbar Discectomy; CUSUM – Cumulative Sum.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/9bd905bf4d3c0c4bdb0e3346.png"},{"id":96365508,"identity":"e7a9eb33-d1a2-4d40-a9f6-04df04f40055","added_by":"auto","created_at":"2025-11-20 10:10:27","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":97238,"visible":true,"origin":"","legend":"\u003cp\u003eCUSUM analysis for Surgeon C. Steady reduction in operative time after case 26.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e CUSUM – Cumulative Sum; IELD – Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/f23106d23b8d3165a3e8e7aa.png"},{"id":96288868,"identity":"3da2f0ba-1e34-4f1f-9ac6-525d531b9b3f","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":21,"title":"Figure 21","display":"","copyAsset":false,"role":"figure","size":150008,"visible":true,"origin":"","legend":"\u003cp\u003eLearning curve for Surgeon A. Initial improvement was observed at case 24, with stabilization at case 49.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e IELD – Interlaminar Endoscopic Lumbar Discectomy; CUSUM – Cumulative Sum.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/b0c2a35b886f64cb825c2c25.png"},{"id":96288867,"identity":"e468efb6-244c-410b-a8d0-862698d71089","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"png","order_by":22,"title":"Figure 22","display":"","copyAsset":false,"role":"figure","size":91870,"visible":true,"origin":"","legend":"\u003cp\u003eCUSUM analysis for Surgeon A. Progressive reduction in operative time following case 24.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e CUSUM – Cumulative Sum; IELD – Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/4f79b48967ea829ed4110f52.png"},{"id":101690825,"identity":"bc6c3f39-1dd4-4adb-9613-5ec5ecd6ba9e","added_by":"auto","created_at":"2026-02-02 16:09:30","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3169736,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/9c5578b2-9e7f-452a-8e30-43393a647c9a.pdf"},{"id":96288851,"identity":"ca210b13-17d5-4424-9fd7-3d1b636c6f55","added_by":"auto","created_at":"2025-11-19 12:13:49","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":18863,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterialSTROBE.docx","url":"https://assets-eu.researchsquare.com/files/rs-8099529/v1/46f113720d2879bc4d4a8a82.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Impact of Arthroscopic Experience on the Learning Curve in Interlaminar Endoscopic Lumbar Discectomy: A Single-Center Prospective Cohort Study of 240 Patients","fulltext":[{"header":"1.\tIntroduction","content":"\u003ch3\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eMinimally invasive spine surgery has rapidly evolved over recent decades, aiming to reduce tissue trauma, accelerate recovery, and minimize perioperative complications [1].\u003cbr\u003e\u0026nbsp;Interlaminar endoscopic lumbar discectomy (IELD) has become an increasingly adopted technique for the treatment of lumbar disc herniation, offering outcomes comparable to conventional microscopic discectomy while providing additional advantages such as reduced soft-tissue damage, less postoperative pain, and faster return to daily activities [2–6].\u003c/p\u003e\n\u003cp\u003eAlthough IELD is clinically effective, its adoption is challenged by a pronounced learning curve, largely attributable to differences in visualization, instrumentation, and operative technique compared with open or microscopic approaches [7,8].\u003cbr\u003e\u0026nbsp;Surgical proficiency in endoscopic procedures depends not only on case volume but also on transferable psychomotor abilities, including hand–eye coordination, triangulation within a confined space, and navigation in a two-dimensional endoscopic environment [9,10].\u003cbr\u003e\u0026nbsp;These competencies closely parallel those required in arthroscopic surgery, where surgeons routinely operate under indirect visualization and continuous fluid irrigation [11,12].\u003c/p\u003e\n\u003cp\u003eArthroscopy and endoscopic spine surgery share several fundamental principles, including limited working space, two-dimensional optics, and the need for precise bimanual coordination.\u003cbr\u003e\u0026nbsp;Therefore, prior arthroscopic experience may facilitate adaptation to endoscopic spinal procedures by reducing the time required to develop depth perception, spatial orientation, and endoscopic dexterity [13,14].\u003cbr\u003e\u0026nbsp;Despite these theoretical similarities, the relationship between arthroscopic experience and the learning process in endoscopic spine surgery has not been systematically evaluated.\u003cbr\u003e\u0026nbsp;Previous studies on the IELD learning curve have primarily focused on the number of cases required for proficiency or complication reduction, but none have directly examined the impact of prior arthroscopic training [15–18].\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003eObjective\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThis prospective single-center cohort study aimed to analyze and compare the learning curves of three surgeons initiating IELD, one of whom had extensive prior arthroscopic experience.\u003cbr\u003e\u0026nbsp;We evaluated operative efficiency, complication rates, and patient-reported outcomes to determine whether arthroscopic skills facilitate adaptation to endoscopic spine surgery.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003eHypothesis\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eWe hypothesized that prior arthroscopic experience would shorten the IELD learning curve and reduce early-phase complications, while long-term patient-reported outcomes would remain consistent across surgeons.\u003cbr\u003e\u0026nbsp;To minimize interindividual variability, all surgeons underwent standardized endoscopic training and operated under identical institutional protocols in accordance with the STROBE reporting guidelines [19].\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cp\u003eStudy Design\u003c/p\u003e\u003cp\u003eThis was a prospective, single-center observational cohort study evaluating the learning curve in interlaminar endoscopic lumbar discectomy (IELD) according to the AOSpine working-channel endoscopy nomenclature [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe primary objective was to assess whether prior arthroscopic experience influences operative efficiency, complication rates, and patient-reported outcomes.\u003c/p\u003e\u003cp\u003eThe study adhered to the \u003cem\u003eStrengthening the Reporting of Observational Studies in Epidemiology (STROBE)\u003c/em\u003e statement [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\u003cp\u003ePatient Population\u003c/p\u003e\u003cp\u003eBetween January 2021 and December 2023, a total of 240 consecutive patients underwent single-level IELD for lumbar disc herniation at a university orthopedic and rehabilitation hospital (single center) affiliated with a medical school.\u003c/p\u003e\u003cp\u003ePatients were assigned consecutively to three endoscopy-na\u0026iuml;ve spine surgeons (A, B, and C) based on operating room availability.\u003c/p\u003e\u003cp\u003eSurgeon A operated on 90 patients, while Surgeons B and C each treated 75 patients.\u003c/p\u003e\u003cp\u003eOne surgeon (B) had prior experience with more than 300 shoulder arthroscopies.\u003c/p\u003e\u003cp\u003eAll procedures were performed independently, without mentoring or technical assistance.\u003c/p\u003e\u003cp\u003eTo minimize interindividual and procedural bias, all surgeries were carried out in a single operating suite with identical equipment, anesthesia team, and nursing staff under a unified perioperative protocol.\u003c/p\u003e\u003cp\u003eInclusion and Exclusion Criteria\u003c/p\u003e\u003cp\u003e\u003cb\u003eInclusion criteria\u003c/b\u003e were:\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u0026bull; Radicular pain refractory to \u0026ge;\u0026thinsp;4 weeks of conservative therapy;\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u0026bull; Neurological deficit (sensory or motor) due to nerve root compression;\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u0026bull; MRI-confirmed single-level lumbar disc herniation;\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u0026bull; Symptom duration\u0026thinsp;\u0026le;\u0026thinsp;3 months;\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u0026bull; Single-level disc herniation at L4/L5 or L5/S1 (MSU zones A/B on axial T2-weighted MRI);\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e \u0026bull; Written informed consent for surgery and study participation.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eExclusion criteria\u003c/b\u003e included:\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u0026bull; Previous lumbar spine surgery;\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u0026bull; Foraminal or extraforaminal disc herniations;\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u0026bull; Calcified or migrated disc fragments beyond endoscopic reach;\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u0026bull; Spondylolisthesis or significant lumbar instability;\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u0026bull; Severe lumbar spinal stenosis.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cp\u003eForaminal herniations were managed using the transforaminal approach and were therefore excluded [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eSurgeon Characteristics and Training\u003c/p\u003e\u003cp\u003eAll three surgeons had at least five years of experience in lumbar spine surgery but no previous endoscopic experience.\u003c/p\u003e\u003cp\u003eEach completed both basic and advanced endoscopic lumbar discectomy training at the dedicated center in Knittlingen, Germany, before initiating clinical practice.\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eSurgeon A\u003c/b\u003e: No prior arthroscopy or endoscopic experience; extensive background in open spine surgery.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eSurgeon B\u003c/b\u003e: \u0026gt;300 prior shoulder arthroscopies; no prior endoscopic spine experience.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eSurgeon C\u003c/b\u003e: No prior arthroscopy or endoscopic experience.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cp\u003eTo ensure standardization, the same endoscopic system (Vertebris, Richard Wolf) and bipolar RF device were used throughout the study.\u003c/p\u003e\u003cp\u003eSurgical Technique\u003c/p\u003e\u003cp\u003eAll procedures were performed under general anesthesia following the interlaminar endoscopic discectomy technique described by Ruetten et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eA 7-mm transverse incision was made, and sequential dilators were inserted to position the working sheath at the medial border of the facet joint.\u003c/p\u003e\u003cp\u003eAfter identification of the ligamentum flavum, it was split to expose the herniated fragment, which was then excised under direct endoscopic vision until decompression of the affected nerve root was achieved.\u003c/p\u003e\u003cp\u003eAdequacy of decompression was confirmed by visualization of free dural pulsation under continuous saline irrigation.\u003c/p\u003e\u003cp\u003eThe incision was closed with a single subcutaneous suture.\u003c/p\u003e\u003cp\u003ePostoperative Management\u003c/p\u003e\u003cp\u003ePostoperative care included non-steroidal anti-inflammatory medication, vitamin B supplementation, and a soft lumbar brace for three weeks.\u003c/p\u003e\u003cp\u003eRoutine postoperative MRI was \u003cb\u003enot\u003c/b\u003e performed. Imaging follow-up was reserved for patients with clinical deterioration, new or persistent radicular pain, or suspected recurrence.\u003c/p\u003e\u003cp\u003ePostoperative MRI was selectively obtained in \u003cb\u003e24 patients (10.0%)\u003c/b\u003e, primarily within the first four postoperative weeks. Among these, \u003cb\u003eone case of epidural hematoma\u003c/b\u003e was confirmed radiologically and managed conservatively without surgical intervention.\u003c/p\u003e\u003cp\u003eThe remaining twenty-three scans demonstrated either residual edema or postoperative changes without compressive pathology.\u003c/p\u003e\u003cp\u003eData Collection and Follow-up\u003c/p\u003e\u003cp\u003eFollow-up examinations were performed at the outpatient spine clinic at 3 and 12 months postoperatively.\u003c/p\u003e\u003cp\u003eFollow-up data were available for 236 of 240 patients (98.3%).\u003c/p\u003e\u003cp\u003eMissing ODI or VAS values in four cases were imputed using the last available observation method.\u003c/p\u003e\u003cp\u003eNo patient was lost to follow-up.\u003c/p\u003e\u003cp\u003eOutcome Measures\u003c/p\u003e\u003cp\u003ePatient-reported outcomes included the \u003cb\u003eOswestry Disability Index (ODI)\u003c/b\u003e [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] and \u003cb\u003eVisual Analog Scale (VAS)\u003c/b\u003e scores for back and leg pain, recorded preoperatively and at 3 and 12 months.\u003c/p\u003e\u003cp\u003eOperative time, intraoperative events, and complications were prospectively documented.\u003c/p\u003e\u003cp\u003eComplications were classified as neurological (nerve root injury, dural tear), recurrence, or minor (hematoma, infection, perineural fibrosis).\u003c/p\u003e\u003cp\u003eA postoperative epidural hematoma was confirmed radiologically on MRI when clinically suspected and treated conservatively.\u003c/p\u003e\u003cp\u003eSample Size and Statistical Analysis\u003c/p\u003e\u003cp\u003eNo formal sample size calculation was performed, as all consecutive eligible patients treated during the study period were included.\u003c/p\u003e\u003cp\u003eThe total cohort size (n\u0026thinsp;=\u0026thinsp;240) exceeded the minimum required for robust CUSUM analysis, as suggested by previous studies [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eLearning curve assessment was performed using cumulative sum (CUSUM) analysis and linear regression.\u003c/p\u003e\u003cp\u003eThe CUSUM statistic was defined as:\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eCUSUM_i\u0026thinsp;=\u0026thinsp;Σ_{j\u0026thinsp;=\u0026thinsp;1..i} (X_j\u0026thinsp;\u0026minus;\u0026thinsp;\u0026micro;)\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ewhere Xj​ represents the operative time for each procedure and \u0026micro; denotes the mean operative time for the entire cohort.\u003c/p\u003e\u003cp\u003eStabilization was defined as three consecutive cases within \u0026plusmn;\u0026thinsp;10% of each surgeon\u0026rsquo;s mean operative time.\u003c/p\u003e\u003cp\u003eContinuous variables (ODI, VAS) were analyzed using one-way ANOVA or Kruskal\u0026ndash;Wallis tests, as appropriate.\u003c/p\u003e\u003cp\u003eComplication rates were compared using Fisher\u0026rsquo;s exact or chi-square tests.\u003c/p\u003e\u003cp\u003eAll analyses were performed with \u003cem\u003eSPSS Statistics v26\u003c/em\u003e (IBM Corp., Armonk, NY, USA), and significance was set at \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 (two-tailed).\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003e\u003cstrong\u003e3.1. Learning Curve of Surgeon A\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 1.\u003c/strong\u003e Learning curve for Surgeon A. Initial improvement was observed at case 24, with stabilization at case 49.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e IELD \u0026ndash; Interlaminar Endoscopic Lumbar Discectomy; CUSUM \u0026ndash; Cumulative Sum.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 2.\u003c/strong\u003e CUSUM analysis for Surgeon A. Progressive reduction in operative time following case 24.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e CUSUM \u0026ndash; Cumulative Sum; IELD \u0026ndash; Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2. Learning Curve of Surgeon B\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 3.\u003c/strong\u003e Learning curve for Surgeon B. Initial improvement occurred at case 12, with stabilization achieved at case 49.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e IELD \u0026ndash; Interlaminar Endoscopic Lumbar Discectomy; CUSUM \u0026ndash; Cumulative Sum.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 4.\u003c/strong\u003e CUSUM analysis for Surgeon B. Rapid decline in operative time after case 12.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e CUSUM \u0026ndash; Cumulative Sum; IELD \u0026ndash; Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3. Learning Curve of Surgeon C\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 5.\u003c/strong\u003e Learning curve for Surgeon C. Initial improvement occurred at case 26, followed by stabilization at case 50.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e IELD \u0026ndash; Interlaminar Endoscopic Lumbar Discectomy; CUSUM \u0026ndash; Cumulative Sum.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 6.\u003c/strong\u003e CUSUM analysis for Surgeon C. Steady reduction in operative time after case 26.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e CUSUM \u0026ndash; Cumulative Sum; IELD \u0026ndash; Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e3.4. Baseline Characteristics\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eBaseline characteristics of the study population are summarized in Table 1.\u003cbr\u003e\u0026nbsp;Demographic and preoperative clinical variables, including age, sex, BMI, symptom duration, and operated level, were comparable across surgeon groups (p = 0.62).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Baseline characteristics of study population\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"3\" cellpadding=\"0\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eVariable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSurgeon A (n=90)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSurgeon B (n=75)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSurgeon C (n=75)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eAge (years, mean \u0026plusmn; SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e42.3 \u0026plusmn; 9.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e43.1 \u0026plusmn; 10.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e41.2 \u0026plusmn; 10.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.71\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eFemale (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e44.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e42.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e46.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eBMI (kg/m\u0026sup2;, mean \u0026plusmn; SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e26.2 \u0026plusmn; 3.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e25.8 \u0026plusmn; 4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e26.1 \u0026plusmn; 3.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eSymptom duration (weeks)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e11.7 \u0026plusmn; 2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e12.1 \u0026plusmn; 2.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e11.9 \u0026plusmn; 2.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.84\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eLevel L4/L5 : L5/S1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e28 : 62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e20 : 55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e18 : 57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.63\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eLegend:\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Baseline demographic and preoperative clinical data of patients undergoing interlaminar endoscopic lumbar discectomy (IELD), stratified by surgeon.\u003cbr\u003e\u0026nbsp;No statistically significant differences were observed between groups (p = 0.62).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e BMI \u0026ndash; Body Mass Index; ODI \u0026ndash; Oswestry Disability Index; VAS \u0026ndash; Visual Analog Scale; IELD \u0026ndash; Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e3.5. Learning Curve Analysis\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eAll three surgeons demonstrated progressive improvement in operative efficiency.\u003cbr\u003e\u0026nbsp;Initial performance improvement was observed at case 24 for Surgeon A, case 12 for Surgeon B, and case 26 for Surgeon C.\u003cbr\u003e\u0026nbsp;Stabilization occurred between the 49th and 53rd case.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2. Linear regression models for operative time\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"3\" cellpadding=\"0\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSurgeon\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eRegression equation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSlope (min/case)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eR\u0026sup2; (Model fit)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eDescription\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ey = \u0026ndash;0.28x + 69.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026ndash;0.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eGradual improvement\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ey = \u0026ndash;0.43x + 74.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026ndash;0.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eFaster reduction\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ey = \u0026ndash;0.62x + 83.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026ndash;0.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eMost dynamic improvement\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eLegend:\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Linear regression parameters illustrating the relationship between operative time and case number for each surgeon.\u003cbr\u003e\u0026nbsp;Negative slope indicates progressive improvement in efficiency.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e CUSUM \u0026ndash; Cumulative Sum; R\u0026sup2; \u0026ndash; Coefficient of determination; min \u0026ndash; minutes.\u003c/p\u003e\n\u003cp\u003eOperative time decreased progressively with experience in all groups, showing a negative correlation between operative time and case number.\u003cbr\u003e\u0026nbsp;Plateau in operative efficiency was reached after approximately 50 cases across all surgeons.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e3.6. CUSUM Analysis\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eCUSUM curves for all surgeons initially trended upward, reflecting longer operative times during the early learning phase.\u003cbr\u003e\u0026nbsp;The inflection point corresponded to performance improvement: case 24 for Surgeon A, 12 for Surgeon B, and 26 for Surgeon C.\u003cbr\u003e\u0026nbsp;Following these peaks, operative times decreased consistently, with all curves plateauing after case 50.\u003cbr\u003e\u0026nbsp;Mean operative times during the stabilization phase were 39.8 \u0026plusmn; 17.3 min (A), 39.3 \u0026plusmn; 12.8 min (B), and 45.6 \u0026plusmn; 16.6 min (C).\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e3.7. Clinical Outcomes\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eAcross the entire cohort, ODI and VAS scores improved significantly from baseline to 12 months (all p \u0026lt; 0.001).\u003cbr\u003e\u0026nbsp;Mean improvement at 12 months was \u0026ndash;20.6 points for ODI, \u0026ndash;5.8 for VAS-back, and \u0026ndash;6.1 for VAS-leg.\u003cbr\u003e\u0026nbsp;When stratified by surgeon and learning phase, all groups demonstrated similar improvements without inter-surgeon differences (Table 3).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3. Clinical outcome measures (ODI and VAS at baseline, 3 and 12 months)\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"3\" cellpadding=\"0\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eTime Point\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eODI (Mean \u0026plusmn; SD)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eVAS Back (Mean \u0026plusmn; SD)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eVAS Leg (Mean \u0026plusmn; SD)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003ep-value (vs baseline)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003ePreoperative\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e33.4 \u0026plusmn; 7.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e7.32 \u0026plusmn; 1.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e7.45 \u0026plusmn; 1.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e3-month follow-up\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e12.2 \u0026plusmn; 7.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2.70 \u0026plusmn; 1.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2.62 \u0026plusmn; 2.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e12-month follow-up\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e6.8 \u0026plusmn; 6.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.41 \u0026plusmn; 1.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.32 \u0026plusmn; 1.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eLegend:\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Functional outcomes at baseline and follow-up showing significant improvement across all time points (p \u0026lt; 0.001).\u003cbr\u003e\u0026nbsp;No significant differences between surgeons were observed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e ODI \u0026ndash; Oswestry Disability Index; VAS \u0026ndash; Visual Analog Scale.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 7.\u003c/strong\u003e Patient-reported outcomes stratified by surgeon and learning phase:\u003cbr\u003e\u0026nbsp;(A) Oswestry Disability Index (ODI) at 12 months;\u003cbr\u003e\u0026nbsp;(B) Visual Analog Scale (VAS) for back pain at 12 months;\u003cbr\u003e\u0026nbsp;(C) Visual Analog Scale (VAS) for leg pain at 12 months.\u003cbr\u003e\u0026nbsp;All surgeons demonstrated marked improvement already during the learning phase, with stable results across the improvement and stabilization phases. No significant differences were found among surgeons (all p \u0026gt; 0.2).\u003cbr\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e ODI \u0026ndash; Oswestry Disability Index; VAS \u0026ndash; Visual Analog Scale; IELD \u0026ndash; Interlaminar Endoscopic Lumbar Discectomy.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e3.8. Complications\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eA total of\u0026nbsp;\u003cstrong\u003e22 complications\u003c/strong\u003e were recorded, corresponding to an overall rate of\u0026nbsp;\u003cstrong\u003e9.2%\u003c/strong\u003e.\u003cbr\u003eComplications occurred most frequently during the initial learning phase (16\u0026ndash;25%) compared with the improvement (5\u0026ndash;13%) and stabilization phases (2\u0026ndash;4%) (\u003cem\u003eOR\u003c/em\u003e 6.7, 95% CI 1.1\u0026ndash;38.9;\u0026nbsp;\u003cem\u003ep\u003c/em\u003e = 0.048) (Table 4).\u003cbr\u003e\u0026nbsp;Neurological complications, including\u0026nbsp;\u003cstrong\u003efour transient nerve root injuries\u003c/strong\u003e and\u0026nbsp;\u003cstrong\u003ethree dural tears\u003c/strong\u003e, were observed exclusively during the learning phase (\u003cem\u003ep\u003c/em\u003e = 0.024).\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eRecurrent disc herniations\u003c/strong\u003e (\u003cem\u003en\u003c/em\u003e = 15, 6.3%) were distributed across all phases without significant association with surgeon experience (\u003cem\u003ep\u003c/em\u003e = 0.62).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePostoperative MRI was performed in 24 patients (10%)\u003c/strong\u003e who presented with persistent or recurrent postoperative pain.\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eMinor events\u003c/strong\u003e included intraoperative foreign body migration, postoperative hematoma (\u003cem\u003en\u003c/em\u003e = 6), and perineural fibrosis (\u003cem\u003en\u003c/em\u003e = 5).\u003cbr\u003e\u0026nbsp;\u003cstrong\u003ePostoperative hematomas were identified on MRI in symptomatic patients and were managed conservatively with good outcomes\u0026mdash;only transient pain symptoms were observed, without neurological sequelae.\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;All minor events resolved spontaneously and were therefore not included in the overall complication rate.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4. Complications stratified by surgeon, phase, and type\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"3\" cellpadding=\"0\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSurgeon\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003ePhase\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eNerve Root Injury\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eDural Tear\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eRecurrence\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eTotal Complications\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eRate (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eLearning\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e16.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eImprovement\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e8.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eStabilization\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eLearning\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e25.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eImprovement\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e5.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eStabilization\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eLearning\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e19.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eImprovement\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e12.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eStabilization\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eTotal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e22\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e9.2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eLegend:\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Distribution of perioperative complications by learning phase and surgeon.\u003cbr\u003e\u0026nbsp;Complications were most frequent during the initial learning phase and decreased with experience.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e IELD \u0026ndash; Interlaminar Endoscopic Lumbar Discectomy; Rate \u0026ndash; percentage of complications within each learning phase; OR \u0026ndash; Odds Ratio; CI \u0026ndash; Confidence Interval.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e3.9. Between-Surgeon Comparisons\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eFunctional outcomes at 12 months (ODI, VAS) and complication rates did not differ significantly among surgeons (all p \u0026gt; 0.2).\u003cbr\u003e\u0026nbsp;Recurrences occurred most frequently within 2\u0026ndash;4 months postoperatively and were often related to premature return to physical work.\u003cbr\u003e\u0026nbsp;Early technical issues such as instrument migration resolved with increasing experience.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 5. Between-surgeon comparisons of outcomes\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"3\" cellpadding=\"0\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eOutcome\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSurgeon A (n=90)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSurgeon B (n=75)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSurgeon C (n=75)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003ep-value (ANOVA)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003ep-value (Kruskal\u0026ndash;Wallis)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eODI preoperative\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e33.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e34.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e34.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.895\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.890\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eODI at 12 months\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e6.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e5.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e7.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.240\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.225\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eVAS back preoperative\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e7.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e7.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e7.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.722\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.608\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eVAS back at 12 months\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.490\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.543\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eVAS leg preoperative\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e7.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e7.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e7.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.894\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.950\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eVAS leg at 12 months\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.779\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.804\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eComplication rate (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e7.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e8.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e12.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026ndash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eFisher/Chi\u0026sup2; p = 0.62\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eLegend:\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Comparison of patient-reported outcomes and complication rates between surgeons at baseline and 12-month follow-up.\u003cbr\u003e\u0026nbsp;No statistically significant differences were found among surgeons (all p \u0026gt; 0.2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e ODI \u0026ndash; Oswestry Disability Index; VAS \u0026ndash; Visual Analog Scale; CUSUM \u0026ndash; Cumulative Sum; Rate \u0026ndash; percentage of complications in phase.\u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis prospective cohort study evaluated the effect of prior arthroscopic experience on the learning curve in interlaminar endoscopic lumbar discectomy (IELD).\u003cbr\u003e\u0026nbsp;Across 240 consecutive cases performed by three surgeons, the learning plateau was reached between the 49th and 53rd procedure, consistent with previously reported thresholds for technical proficiency in endoscopic lumbar discectomy [7–10].\u003cbr\u003e\u0026nbsp;Although the surgeon with prior arthroscopic experience achieved stabilization earlier, this did not translate into superior long-term functional outcomes or lower overall complication rates.\u003cbr\u003e\u0026nbsp;These findings suggest that arthroscopic skills facilitate early procedural adaptation but do not independently influence final clinical recovery.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e4.1. Comparison with Previous Literature\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003ePrevious studies investigating the learning curve in endoscopic lumbar discectomy have demonstrated wide variability in the number of cases required to achieve proficiency.\u003cbr\u003e\u0026nbsp;Ruetten et al. [10] reported that 40–60 cases were typically required for stabilization, while Lee et al. [12] found plateau points between 30 and 55 cases based on operative time and complication reduction.\u003cbr\u003e\u0026nbsp;Our results, showing stabilization after approximately 50 cases, are therefore consistent with these benchmarks and reinforce the reproducibility of the learning pattern across different institutions.\u003c/p\u003e\n\u003cp\u003eCUSUM analysis has been widely used to quantify technical progression in endoscopic spine surgery.\u003cbr\u003e\u0026nbsp;Huang et al. [18] and Kim et al. [20] described steep declines in operative time within the first 20–40 cases, followed by plateauing performance — closely mirroring our findings.\u003cbr\u003e\u0026nbsp;The present study adds a novel perspective by prospectively comparing surgeons with and without arthroscopic experience, providing direct evidence that prior arthroscopy training may accelerate early technical adaptation, particularly during the transition from microscopic to endoscopic visualization.\u003c/p\u003e\n\u003cp\u003eArthroscopic surgery involves operating in a fluid-filled, two-dimensional field under indirect visualization, requiring precise bimanual coordination and triangulation.\u003cbr\u003e\u0026nbsp;These psychomotor skills are analogous to those employed in endoscopic spine surgery [21–23].\u003cbr\u003e\u0026nbsp;This likely explains the earlier improvement phase observed in the arthroscopy-experienced surgeon (case 12 versus 24–26 in the others).\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e4.2. Functional Outcomes\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eAll surgeons achieved significant improvements in ODI and VAS scores, consistent with previous IELD series [2,3,5,6].\u003cbr\u003e\u0026nbsp;In a meta-analysis by Sairyo et al. [8], mean ODI reduction after endoscopic lumbar discectomy ranged from 20 to 25 points, and VAS-leg improvement from 5 to 6 points — values nearly identical to those observed in our cohort (ΔODI = 26.6, ΔVAS-leg = 6.1).\u003cbr\u003e\u0026nbsp;These results confirm that patients benefit from the minimally invasive nature of IELD even during the early learning phase, provided that case selection and procedural protocols are standardized.\u003c/p\u003e\n\u003cp\u003eNo association was observed between prior arthroscopic experience and long-term patient-reported outcomes, which remained uniformly favorable across surgeons.\u003cbr\u003e\u0026nbsp;This indicates that while arthroscopic experience may accelerate early technical mastery, ultimate clinical recovery depends primarily on surgical indication, procedural precision, and structured postoperative care rather than prior training background.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e4.3. Complications and Safety Profile\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThe overall complication rate of 9.2% observed in this study aligns with previously reported values (5–12%) [7, 10, 13].\u003cbr\u003e\u0026nbsp;Most complications occurred during the early learning phase, particularly transient nerve root irritation and dural tears, which decreased substantially after stabilization.\u003cbr\u003e\u0026nbsp;This trend mirrors prior CUSUM-based analyses showing that early-phase complications can be up to three times more frequent than in later stages [9, 14].\u003c/p\u003e\n\u003cp\u003eA single postoperative epidural hematoma was confirmed by MRI and managed conservatively with complete resolution and no neurological sequelae.\u003cbr\u003e\u0026nbsp;Selective postoperative MRI was performed in a small subset of symptomatic patients with persistent or recurrent pain, ensuring adequate evaluation of clinically significant complications while avoiding unnecessary routine imaging.\u003cbr\u003e\u0026nbsp;The recurrence rate of lumbar disc herniation was 6.3%, consistent with the 5–8% reported in the literature [3, 6, 13].\u003cbr\u003e\u0026nbsp;Most recurrences occurred within the first 3–4 months after surgery and were associated with premature return to physically demanding work.\u003cbr\u003e\u0026nbsp;These findings emphasize the importance of structured postoperative rehabilitation and patient education following IELD.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e4.4. Impact of Arthroscopic Experience on Learning Curve\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThe surgeon with prior arthroscopic experience entered the improvement phase earlier (case 12 vs. 24–26 for the other surgeons), indicating a faster initial adaptation to endoscopic instrumentation and visualization.\u003cbr\u003e\u0026nbsp;This finding supports the concept that psychomotor and spatial orientation skills acquired through arthroscopy—such as triangulation, camera control, and bimanual coordination—are transferable to endoscopic spine surgery.\u003cbr\u003e\u0026nbsp;Such familiarity likely enhances confidence and dexterity during the early learning phase, reducing hesitation and technical errors when operating in a two-dimensional endoscopic environment.\u003c/p\u003e\n\u003cp\u003eHowever, once technical stabilization was achieved, operative times, complication rates, and patient-reported outcomes converged across all surgeons.\u003cbr\u003e\u0026nbsp;This suggests that the advantage conferred by prior arthroscopic experience is confined primarily to the early stage of the learning process.\u003cbr\u003e\u0026nbsp;As surgical exposure and experience accumulate, performance equalizes regardless of previous arthroscopic background.\u003cbr\u003e\u0026nbsp;These observations support the inclusion of arthroscopic simulation, cadaveric dissection, or dry-lab endoscopic exercises in structured spine training curricula to accelerate skill acquisition and shorten the early learning curve in novice endoscopic surgeons.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e4.5. Study Limitations\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThis study has several limitations that should be acknowledged.\u003cbr\u003e\u0026nbsp;First, the comparison involved only three surgeons, with one having prior arthroscopic experience.\u003cbr\u003e\u0026nbsp;Although all surgeons had comparable backgrounds in spine surgery and completed identical endoscopic training, this small sample introduces potential operator-related bias and limits generalizability.\u003cbr\u003e\u0026nbsp;Second, the single-center design may not fully reflect variations in institutional infrastructure, surgical culture, or case selection that could influence the learning curve.\u003cbr\u003e\u0026nbsp;Future multicenter studies involving a larger and more diverse group of surgeons with varying arthroscopic backgrounds are warranted to confirm these findings.\u003cbr\u003e\u0026nbsp;Third, the follow-up period of 12 months, although sufficient to evaluate short-term recovery and early recurrence, does not allow assessment of long-term sequelae such as adjacent segment degeneration or reherniation beyond one year.\u003cbr\u003e\u0026nbsp;Finally, while the CUSUM approach offers an objective quantitative measure of operative efficiency and error reduction, it does not capture qualitative aspects of decision-making, tissue handling, or ergonomic performance that may also contribute to surgical proficiency.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003e4.6. Clinical Implications and Conclusions\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThe findings of this study have direct implications for surgical education and training in minimally invasive spine procedures.\u003cbr\u003e\u0026nbsp;Interlaminar endoscopic lumbar discectomy (IELD) requires a distinct psychomotor skill set that differs from open and microscopic techniques.\u003cbr\u003e\u0026nbsp;Surgeons with prior arthroscopic experience may adapt more rapidly during the early learning phase due to transferable visuospatial and bimanual coordination skills.\u003cbr\u003e\u0026nbsp;Therefore, incorporating structured exposure to arthroscopic or endoscopic simulation, cadaveric workshops, and virtual-reality–based modules into standardized training curricula may accelerate technical proficiency and reduce early-phase complications.\u003cbr\u003e\u0026nbsp;Competency-based, modular training models similar to those used in arthroscopy and laparoscopy could improve the safety and reproducibility of endoscopic spine surgery as the field continues to expand.\u003c/p\u003e\n\u003cp\u003eIn conclusion, prior arthroscopic experience appears to shorten the initial learning curve in interlaminar endoscopic lumbar discectomy, facilitating faster technical adaptation without compromising safety or long-term outcomes.\u003cbr\u003e\u0026nbsp;Once procedural stabilization is achieved, operative times, complication rates, and functional recovery become comparable among surgeons regardless of their previous arthroscopic background.\u003cbr\u003e\u0026nbsp;These results highlight the reproducible nature of the IELD learning curve and the transferable value of arthroscopic psychomotor skills, supporting the integration of targeted simulation and structured mentorship into contemporary endoscopic spine training programs.\u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eInterlaminar endoscopic lumbar discectomy (IELD) is a safe and effective procedure characterized by a three-phase learning curve, reaching stabilization after approximately 50 cases.\u003cbr\u003e\u0026nbsp;Prior arthroscopic experience facilitates a faster transition through the early learning phase and may reduce initial technical errors, although long-term functional outcomes and complication rates remain comparable across surgeons.\u003cbr\u003e\u0026nbsp;These findings confirm the reproducible nature of the IELD learning curve and highlight the transferable value of arthroscopic psychomotor skills in accelerating adaptation to endoscopic techniques.\u003cbr\u003e\u0026nbsp;Integrating arthroscopic or endoscopic simulation-based modules into structured, competency-oriented training programs may enhance surgical education and improve early procedural safety.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e\u003cstrong\u003eBMI\u003c/strong\u003e \u0026ndash; Body Mass Index\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eCI\u003c/strong\u003e \u0026ndash; Confidence Interval\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eCUSUM\u003c/strong\u003e \u0026ndash; Cumulative Sum\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eESJ\u003c/strong\u003e \u0026ndash; European Spine Journal\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eIELD\u003c/strong\u003e \u0026ndash; Interlaminar Endoscopic Lumbar Discectomy\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eMRI\u003c/strong\u003e \u0026ndash; Magnetic Resonance Imaging\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eMSU\u003c/strong\u003e \u0026ndash; Michigan State University Classification\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eODI\u003c/strong\u003e \u0026ndash; Oswestry Disability Index\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eOR\u003c/strong\u003e \u0026ndash; Odds Ratio\u003cbr\u003e\u0026nbsp;\u003cstrong\u003ePROs\u003c/strong\u003e \u0026ndash; Patient-Reported Outcomes\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eRF\u003c/strong\u003e \u0026ndash; Radiofrequency\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eVAS\u003c/strong\u003e \u0026ndash; Visual Analog Scale\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch3\u003e\u003cstrong\u003eEthics Statement\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThe study was conducted in accordance with the Declaration of Helsinki and was approved by the Bioethics Committee of the Jagiellonian University (Decision No. 1072.6120321.2021, dated December 15, 2021).\u003cbr\u003e\u0026nbsp;All patients provided written informed consent prior to participation.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003eData Availability Statement\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThe datasets generated and analyzed during the current study are not publicly available due to patient privacy and institutional policy but are available from the corresponding author on reasonable request.\u003cbr\u003e\u0026nbsp;All data were collected and securely stored at the University Orthopedic and Rehabilitation Hospital in Zakopane, Department and Clinic of Orthopedics and Rehabilitation, Collegium Medicum, Jagiellonian University, Krak\u0026oacute;w, Poland.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. The study was self-funded by the authors.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003eConflict of Interest\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThe authors declare that they have no conflicts of interest related to this study.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor A\u003c/strong\u003e designed the study and performed the surgeries.\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eAuthor B\u003c/strong\u003e conducted the data analysis.\u003cbr\u003e\u0026nbsp;\u003cstrong\u003eAuthor C\u003c/strong\u003e contributed to manuscript writing and literature review.\u003cbr\u003e\u0026nbsp;All authors read and approved the final version of the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSmith JS, Fessler RG. Paradigm changes in spine surgery: evolution of minimally invasive techniques. \u003cem\u003eEur Spine J\u003c/em\u003e. 2012;21(4):556\u0026ndash;568.\u003c/li\u003e\n\u003cli\u003eRuetten S, Komp M, Merk H, Godolias G. Full-endoscopic interlaminar and transforaminal lumbar discectomy versus conventional microsurgical technique: a prospective, randomized, controlled study. \u003cem\u003eSpine (Phila Pa 1976)\u003c/em\u003e. 2008;33(9):931\u0026ndash;939.\u003c/li\u003e\n\u003cli\u003eChoi G, Lee SH, Lokhande P, Kong BJ, Shim CS, Jung B, et al. Percutaneous endoscopic interlaminar discectomy for L5\u0026ndash;S1 disc herniation: technique, outcome, and complications. \u003cem\u003eMinim Invasive Neurosurg\u003c/em\u003e. 2011;54(2):81\u0026ndash;87.\u003c/li\u003e\n\u003cli\u003eAhn Y, Lee SH, Park WM, Lee HY, Shin SW, Kang HY. Percutaneous endoscopic lumbar discectomy for recurrent disc herniation: surgical technique, outcome, and prognostic factors. \u003cem\u003eJ Neurosurg Spine\u003c/em\u003e. 2012;16(6):601\u0026ndash;607.\u003c/li\u003e\n\u003cli\u003eKomp M, Hahn P, Oezdemir S, Ruetten S. Bilateral spinal decompression of lumbar central stenosis with the full-endoscopic interlaminar technique: technique and prospective results of 163 cases. \u003cem\u003eWorld Neurosurg\u003c/em\u003e. 2015;84(5):964\u0026ndash;971.\u003c/li\u003e\n\u003cli\u003eHeo DH, Quillo-Olvera J, Park CK. Complications of endoscopic lumbar surgery and strategy for prevention. \u003cem\u003eWorld J Clin Cases\u003c/em\u003e. 2020;8(1):100\u0026ndash;113.\u003c/li\u003e\n\u003cli\u003eAhn Y, Lee HY, Lee SH, Lee JH. Learning curve for percutaneous endoscopic lumbar discectomy: prospective analysis of the first 50 cases performed by a single surgeon. \u003cem\u003eSpine (Phila Pa 1976)\u003c/em\u003e. 2013;38(6):E494\u0026ndash;E501.\u003c/li\u003e\n\u003cli\u003eLee DY, Ahn Y, Lee SH. Percutaneous endoscopic lumbar discectomy learning curve for surgeons experienced in microscopic discectomy. \u003cem\u003eSpine (Phila Pa 1976)\u003c/em\u003e. 2012;37(18):1543\u0026ndash;1548.\u003c/li\u003e\n\u003cli\u003eChoi KC, Kim JS, Lee DC, Park CK. Learning curve associated with complications in biportal endoscopic spinal surgery: challenges and strategies. \u003cem\u003eWorld Neurosurg\u003c/em\u003e. 2019;132:e926\u0026ndash;e932.\u003c/li\u003e\n\u003cli\u003eRuetten S, Komp M, Oezdemir S, Godolias G. Technique of transforaminal endoscopic lumbar discectomy with foraminoplasty. \u003cem\u003eEur Spine J\u003c/em\u003e. 2009;18(3):461\u0026ndash;467.\u003c/li\u003e\n\u003cli\u003eBarret DS, Cobb AG, Bentley G. Arthroscopic training\u0026mdash;skills transfer from orthopaedics to endoscopy. \u003cem\u003eAnn R Coll Surg Engl\u003c/em\u003e. 1995;77(3):173\u0026ndash;176.\u003c/li\u003e\n\u003cli\u003eKim SJ, Choi NH, Kim H, Victoroff BN. Arthroscopic skills acquisition and transfer: comparison between orthopedic and general surgeons. \u003cem\u003eArthroscopy\u003c/em\u003e. 2004;20(4):375\u0026ndash;380.\u003c/li\u003e\n\u003cli\u003eKim HS, Wu PH, Jang IT. Technical advancements in endoscopic spine surgery: navigating the learning curve. \u003cem\u003eJ Minim Invasive Spine Surg Tech\u003c/em\u003e. 2021;6(2):243\u0026ndash;250.\u003c/li\u003e\n\u003cli\u003eHeo DH, Kim JS, Park CK. Learning curve and safety of full-endoscopic lumbar surgery: cumulative summation analysis of 250 cases. \u003cem\u003eWorld Neurosurg\u003c/em\u003e. 2020;138:e450\u0026ndash;e457.\u003c/li\u003e\n\u003cli\u003eSairyo K, Higashino K, Sakai T, et al. History and evolution of endoscopic spinal surgery: learning from the past and advancing toward the future. \u003cem\u003eGlob Spine J\u003c/em\u003e. 2022;12(1):66\u0026ndash;75.\u003c/li\u003e\n\u003cli\u003eLiu X, Yuan S, Tian W, et al. CUSUM learning curve analysis of full-endoscopic lumbar discectomy. \u003cem\u003eEur Spine J\u003c/em\u003e. 2020;29(8):1899\u0026ndash;1907.\u003c/li\u003e\n\u003cli\u003eKang T, Park SY, Park JH, et al. Learning curve for interlaminar endoscopic lumbar discectomy: CUSUM analysis of 120 consecutive cases. \u003cem\u003eSpine J\u003c/em\u003e. 2021;21(9):1522\u0026ndash;1530.\u003c/li\u003e\n\u003cli\u003eHofstetter CP, Ahn Y, Choi G, et al. Endoscopic lumbar spine surgery: state of the art and future directions. \u003cem\u003eNeurosurg Focus\u003c/em\u003e. 2019;46(5):E14.\u003c/li\u003e\n\u003cli\u003evon Elm E, Altman DG, Egger M, Pocock SJ, G\u0026oslash;tzsche PC, Vandenbroucke JP; STROBE Initiative. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. \u003cem\u003eInt J Surg\u003c/em\u003e. 2014;12(12):1495\u0026ndash;1499.\u003c/li\u003e\n\u003cli\u003eTelfeian AE, Choi DB, Ahn Y. Learning curve analysis of transforaminal endoscopic lumbar discectomy. \u003cem\u003eWorld Neurosurg\u003c/em\u003e. 2019;128:e850\u0026ndash;e856.\u003c/li\u003e\n\u003cli\u003eWu PH, Kim HS, Jang IT. How to master lumbar endoscopic discectomy: tips and tricks for overcoming the learning curve. \u003cem\u003eEur Spine J\u003c/em\u003e. 2020;29(Suppl 1):29\u0026ndash;39.\u003c/li\u003e\n\u003cli\u003eYeung AT, Tsou PM. Posterolateral endoscopic excision for lumbar disc herniation: surgical technique, outcome, and complications. \u003cem\u003eSpine (Phila Pa 1976)\u003c/em\u003e. 2002;27(7):722\u0026ndash;731.\u003c/li\u003e\n\u003cli\u003eKotheeranurak V, Jitpakdee K, Kim JS. Complications and risk factors in endoscopic lumbar spine surgery: a systematic review. \u003cem\u003eGlob Spine J\u003c/em\u003e. 2022;12(3):471\u0026ndash;489.\u003c/li\u003e\n\u003cli\u003eKim JS, Jung B, Lee SH. Instrumentation and visualization challenges in full-endoscopic lumbar discectomy. \u003cem\u003eClin Orthop Surg\u003c/em\u003e. 2016;8(3):325\u0026ndash;332.\u003c/li\u003e\n\u003cli\u003eLee CW, Yoon KJ, Ha SS. Comparison of endoscopic discectomy and microdiscectomy in lumbar disc herniation: minimum 2-year follow-up. \u003cem\u003eEur Spine J\u003c/em\u003e. 2015;24(5):939\u0026ndash;946.\u003c/li\u003e\n\u003cli\u003eAhn Y. Endoscopic spine discectomy: current status and future perspectives. \u003cem\u003eAsian Spine J\u003c/em\u003e. 2020;14(5):682\u0026ndash;697.\u003c/li\u003e\n\u003cli\u003eWang T, Li Z, Wang Y, et al. Postoperative epidural hematoma after endoscopic lumbar surgery: incidence, risk factors, and management. \u003cem\u003eWorld Neurosurg\u003c/em\u003e. 2021;149:e113\u0026ndash;e121.\u003c/li\u003e\n\u003cli\u003eCho JY, Lee SH, Kim WC. Risk factors and management of recurrent lumbar disc herniation after percutaneous endoscopic lumbar discectomy. \u003cem\u003eWorld Neurosurg\u003c/em\u003e. 2017;99:425\u0026ndash;433.\u003c/li\u003e\n\u003cli\u003eAkbary K, Kim JS, Park CW. Early postoperative outcomes and learning curve of endoscopic interlaminar lumbar discectomy. \u003cem\u003eClin Neurol Neurosurg\u003c/em\u003e. 2018;173:183\u0026ndash;189.\u003c/li\u003e\n\u003cli\u003eSclafani JA, Kim CW. Complications associated with minimally invasive spine surgery. \u003cem\u003eJ Am Acad Orthop Surg\u003c/em\u003e. 2014;22(9):464\u0026ndash;472.\u003c/li\u003e\n\u003cli\u003eHeo DH, Park CK. Comparative analysis of learning curves and outcomes between interlaminar and transforaminal endoscopic discectomy. \u003cem\u003eWorld Neurosurg\u003c/em\u003e. 2019;127:e748\u0026ndash;e755.\u003c/li\u003e\n\u003cli\u003eWu PH, Jang IT, Kim HS. Transferrable arthroscopic psychomotor skills for endoscopic spine surgeons: a training perspective. \u003cem\u003eJ Minim Invasive Spine Surg Tech\u003c/em\u003e. 2022;7(1):12\u0026ndash;19.\u003c/li\u003e\n\u003cli\u003eHofstetter CP, Ahn Y, Choi G. Minimally invasive and endoscopic approaches to the lumbar spine. \u003cem\u003eNeurosurg Clin N Am\u003c/em\u003e. 2020;31(1):17\u0026ndash;26.\u003c/li\u003e\n\u003cli\u003eHeo DH, Kim JS. The role of competency-based training in endoscopic spine surgery. \u003cem\u003eGlob Spine J\u003c/em\u003e. 2023;13(4):515\u0026ndash;523.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-spine-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esjo","sideBox":"Learn more about [European Spine Journal](http://link.springer.com/journal/586)","snPcode":"586","submissionUrl":"https://submission.springernature.com/new-submission/586/3","title":"European Spine Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Interlaminar approach, Endoscopic lumbar discectomy, Learning curve, Arthroscopic experience, CUSUM analysis, Surgical education, Minimally invasive spine surgery","lastPublishedDoi":"10.21203/rs.3.rs-8099529/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8099529/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eStudy Design:\u003c/strong\u003e Prospective single-center observational cohort study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObjectives:\u003c/strong\u003e\u003cbr\u003e\nTo evaluate whether prior arthroscopic experience shortens the learning curve in interlaminar endoscopic lumbar discectomy (IELD) and influences complication rates and patient-reported outcomes (PROs).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e\u003cbr\u003e\nIn accordance with STROBE guidelines, 240 consecutive patients with single-level lumbar disc herniation (MSU A/B, non-calcified, symptom duration ≤ 3 months) underwent IELD between 2021 and 2023 at the University Orthopedic and Rehabilitation Hospital in Zakopane, affiliated with the Department and Clinic of Orthopedics and Rehabilitation, Collegium Medicum, Jagiellonian University.\u003cbr\u003e\nProcedures were performed by three spine surgeons with no prior endoscopic experience; one had completed \u0026gt; 300 shoulder arthroscopies.\u003cbr\u003e\nOperative times were analyzed using cumulative sum (CUSUM) and linear regression.\u003cbr\u003e\nMissing data were managed using last available observation.\u003cbr\u003e\nComplications were stratified by type, phase, and surgeon.\u003cbr\u003e\nOswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back and leg pain were assessed preoperatively and at 3 and 12 months.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e\u003cbr\u003e\nAll surgeons demonstrated a three-phase learning curve (learning, improvement, stabilization).\u003cbr\u003e\nTechnical stabilization occurred after approximately 50 cases.\u003cbr\u003e\nThe arthroscopy-experienced surgeon reached improvement earlier (case 12) than others (cases 24–26).\u003cbr\u003e\nOverall complication rate was 9.2%, highest during the learning phase (up to 25%).\u003cbr\u003e\nA single postoperative epidural hematoma was confirmed on MRI and resolved conservatively.\u003cbr\u003e\nODI and VAS improved significantly at 3 and 12 months (p \u0026lt; 0.001), with no between-surgeon differences at final follow-up.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e\u003cbr\u003e\nPrior arthroscopic experience facilitates early adaptation to endoscopic visualization and may reduce initial neurological risk, but long-term outcomes remain comparable among surgeons.\u003cbr\u003e\nThe study confirms IELD as a safe, effective technique with a reproducible ~50-case learning curve.\u003cbr\u003e\n \u003cstrong\u003eLevel of Evidence:\u003c/strong\u003e III\u003c/p\u003e","manuscriptTitle":"Impact of Arthroscopic Experience on the Learning Curve in Interlaminar Endoscopic Lumbar Discectomy: A Single-Center Prospective Cohort Study of 240 Patients","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-19 12:13:44","doi":"10.21203/rs.3.rs-8099529/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-17T07:25:58+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-17T05:35:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"211875111027721728121614913256364418491","date":"2025-12-17T04:46:25+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-16T06:20:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"211566829384891054772016398984002981106","date":"2025-12-16T03:24:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"315821334967744085775734069669407695151","date":"2025-12-16T01:11:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"43732069605538402973864763372408294158","date":"2025-12-15T05:37:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"286720530013738714999139895197614560724","date":"2025-12-14T23:46:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"57462263917728741194182354096960199898","date":"2025-12-07T20:19:31+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"204472418554379975168757575017960893291","date":"2025-12-04T12:19:22+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-20T14:26:46+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-20T02:10:21+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-20T02:09:24+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Spine Journal","date":"2025-11-12T20:08:46+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-spine-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esjo","sideBox":"Learn more about [European Spine Journal](http://link.springer.com/journal/586)","snPcode":"586","submissionUrl":"https://submission.springernature.com/new-submission/586/3","title":"European Spine Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"4445f6bc-d2af-42c3-bb62-bdcc181ef1e4","owner":[],"postedDate":"November 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-02-02T16:05:58+00:00","versionOfRecord":{"articleIdentity":"rs-8099529","link":"https://doi.org/10.1007/s00586-026-09758-8","journal":{"identity":"european-spine-journal","isVorOnly":false,"title":"European Spine Journal"},"publishedOn":"2026-01-28 15:58:43","publishedOnDateReadable":"January 28th, 2026"},"versionCreatedAt":"2025-11-19 12:13:44","video":"","vorDoi":"10.1007/s00586-026-09758-8","vorDoiUrl":"https://doi.org/10.1007/s00586-026-09758-8","workflowStages":[]},"version":"v1","identity":"rs-8099529","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8099529","identity":"rs-8099529","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}