Assisted full-endoscopic spine surgery for lumbar spinal stenosis: Technical note and learning curve.

Introduction: Lumbar spinal stenosis (LSS) causes disabling back and radicular pain. Full-endoscopic spine surgery offers minimally invasive decompression, but uniportal and biportal approaches have limitations. Assisted full-endoscopic spine surgery (AFESS) combines the advantages of both techniques to enhance decompression while preserving facet joints. Research question: Can AFESS provide effective decompression with high facet preservation for LSS, and what is the learning curve for this technique? Material and methods: We retrospectively reviewed 33 patients with single-level LSS treated with AFESS, divided into initial (20 cases) and advanced (13 cases) phases. Outcomes assessed at a minimum 6-month follow-up included operative time, facet joint preservation ratio, complications, and visual analog scale (VAS) scores for back and leg pain. Results: Operative time decreased significantly from the initial to the advanced phase (mean 99 vs 72 min; p < 0.01). Facet joints were more preserved in the advanced phase (76.2 % vs 68.9 %, p < 0.05). In the initial and advanced phases, mean lumbar VAS improved from 4.2 to 1.1 cm and 2.8 to 0.2 cm, respectively. Radicular VAS improved from 7.7 to 0.8 cm (initial) and 6.9 to 0.9 cm (advanced) (p < 0.01 for all). Two patients (6 %) experienced minor complications in the initial phase, with no permanent deficits. Discussion and conclusion: AFESS is safe and effective, achieving adequate decompression with high facet preservation and significant pain relief in LSS patients. By integrating uniportal and biportal endoscopic approaches, AFESS overcomes limitations of each. The well-defined learning curve suggests it can be efficiently incorporated into clinical practice with minimal complications.