A Retrospective Comparative Study on Arthroscopic-Assisted Uni-Portal Spinal Surgery (AUSS/UNSES) Versus Unilateral Biportal Endoscopy for Double-Segment Lumbar Spinal Stenosis.

OBJECTIVE: Conventional endoscopic decompression for double-segment lumbar spinal stenosis (LSS) generally requires multiple portals and incisions, which may increase tissue disruption, procedural complexity, and radiation exposure. Evidence is limited on whether two adjacent levels can be adequately decompressed through a single-incision, non-coaxial approach. To compare the clinical efficacy, perioperative outcomes, and safety of double-segment arthroscopic-assisted uni-portal spinal surgery (DS-AUSS/DS-UNSES) with double-segment unilateral biportal endoscopy (DS-UBE) for unilateral laminotomy with bilateral decompression (ULBD). METHODS: This retrospective comparative study included 103 patients who underwent double-segment ULBD between January 2022 and January 2024 (DS-AUSS, n = 55; DS-UBE, n = 48). Visual Analog Scale (VAS), Oswestry Disability Index (ODI), anterior-posterior diameter of the canal, Schizas stenosis grade, modified MacNab criteria, perioperative parameters, and complications were evaluated. Independent-samples t-tests, Mann-Whitney U tests, Chi-square or Fisher exact tests, and mixed-design repeated-measures analysis of variance with Bonferroni-corrected post hoc comparisons were used. RESULTS: Both groups showed significant postoperative improvements in VAS, ODI, and stenosis grade (p < 0.05). Compared with DS-UBE, DS-AUSS produced lower VAS scores at postoperative Day 3 (mean difference, -0.75; 95% CI, -1.08 to -0.42; p < 0.001) and lower ODI at 3 months (mean difference, -5.53%; 95% CI, -8.84 to -2.22; p = 0.001). DS-AUSS also reduced operative time (mean difference, -16.94 min; p < 0.001), intraoperative blood loss (median difference, -12.0 mL; p = 0.024), postoperative drainage (mean difference, -16.14 mL; p < 0.001), fluoroscopy frequency (median difference, -2.0; p < 0.001), and hospital stay (mean difference, -1.18 days; p = 0.007). At 12 months, Grade A/B stenosis improvement (96.4% vs. 93.8%; p = 0.490) and MacNab excellent/good rates (92.73% in both groups; p = 0.633) were comparable. Overall complication rates were 7.3% and 14.6%, respectively (p = 0.350). CONCLUSION: DS-AUSS achieved 1-year clinical and radiographic outcomes comparable to DS-UBE while improving perioperative efficiency, reducing tissue trauma and fluoroscopy exposure, and accelerating early recovery. It is a feasible minimally invasive option for selected patients with double-segment LSS.