Does Arthroscopic Experience Shorten the Learning Curve in Endoscopic Lumbar Discectomy? A Prospective Cohort of 240 Patients

Abstract Study Design: Prospective observational cohort study. Objectives: To evaluate whether prior arthroscopic experience accelerates the learning curve in interlaminar endoscopic lumbar discectomy (IELD) and influences complication rates and patient-reported outcomes (PROs). Methods: A total of 240 consecutive patients with symptomatic lumbar disc herniation (MSU A/B, non-calcified, symptom duration ≤3 months) underwent single-level IELD performed by three endoscopy-naïve spine surgeons; one had previously performed >300 shoulder arthroscopies. Operative times were analyzed using CUSUM and linear regression, with stabilization defined as ≥3 consecutive cases within ±10% of each surgeon’s mean time. Complications were stratified by type, phase, and surgeon. ODI and VAS (back/leg) were recorded preoperatively and at 3 and 12 months. Results: All surgeons demonstrated a three-phase pattern (learning, improvement, stabilization). Surgeons without arthroscopic background exited the learning phase at ~case 25 and stabilized by case 49–53, while the arthroscopy-experienced surgeon improved by case 12. Mean operative times at stabilization were 39.8, 39.3, and 45.6 minutes. Neurological complications (nerve-root injuries, n=4; dural tears, n=3) occurred exclusively in the learning phase (p=0.024). Recurrent herniations (n=15) were phase-independent (p=0.62). All groups showed significant improvement in ODI and VAS at 3 and 12 months (p<0.001), with no differences between surgeons at final follow-up. Conclusions: IELD is safe and effective, but early neurological risk is learning-dependent. Prior arthroscopic experience markedly shortens the learning curve and may lower perioperative risk, without altering long-term PROs. These findings highlight the potential role of arthroscopic skill transfer in endoscopic spine training curricula. Level of Evidence: III