Learning Curve for Biportal Endoscopic Transforaminal Lumbar Interbody Fusion in a Junior Endoscopic Spine Surgeon: A...

Biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) is an emerging minimally invasive spinal fusion technique with unique technical demands. Understanding its learning curve is essential for improving surgical efficiency and ensuring patient safety, particularly for junior surgeons with prior biportal decompression experience but limited fusion background.

We retrospectively analyzed 70 consecutive BE-TLIF levels performed by a single junior surgeon with extensive biportal decompression but limited minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) experience (< 10 cases). Learning progression was assessed using learning curve-cumulative summation (LC-CUSUM) and exponential regression analyses. Operative times were evaluated across 6 surgical phases, and perioperative and clinical outcomes were compared between groups stratified by LC-CUSUM proficiency.

LC-CUSUM identified procedural competence after 62 levels, while exponential regression demonstrated plateauing around 43 cases. Phase-specific analysis revealed significant reductions in approach and decompression times, with the greatest improvement in cage insertion (37.1% reduction). Bone grafting time increased with experience, reflecting more meticulous technique. Clinical outcomes, including Oswestry Disability Index and Functional Rating Index scores, improved significantly in both groups, with greater functional recovery and fewer complications observed in later cases.

BE-TLIF demonstrates a phase-specific learning curve, with proficiency achieved after sufficient case volume. Structured training focusing on decompression and cage insertion may accelerate skill acquisition. Comprehensive inclusion of multi-level cases and phase-specific time analysis provide a robust framework for evaluating technical proficiency in endoscopic spine surgery training.