Unilateral biportal endoscopic decompression versus microscopic or microendoscopic decompression for single-level lumbar spinal stenosis: an updated systematic review and meta-analysis

Abstract Background Unilateral biportal endoscopic (UBE) decompression is increasingly used for lumbar spinal stenosis (LSS), but previous reviews conflated microscopic and microendoscopic comparators and sometimes mixed single- and multilevel cohorts. We updated the evidence for single-level decompression and examined whether comparator type, study design and postoperative time point explained between-study variation. Methods We searched PubMed, Embase, Web of Science Core Collection, Scopus and the Cochrane Central Register of Controlled Trials (CENTRAL), searched via the Cochrane Library, from inception to 2 September 2026 using database-specific UBE and LSS concepts without requiring a comparator term. Comparative studies of UBE versus microscopic or microendoscopic decompression for single-level degenerative LSS were eligible. Random-effects models used restricted maximum likelihood with modified Hartung–Knapp confidence intervals. Heterogeneity, prediction intervals, comparator and design subgroups, and leave-one-out analyses were examined. Results The updated evidence set comprised 15 studies and 1,426 participants. No clear between-group difference was found for early back-pain VAS (MD − 0.71, 95% CI − 2.06 to 0.64), early leg-pain VAS (MD − 0.25, − 0.72 to 0.23), long-term back-pain VAS (MD − 0.02, − 0.15 to 0.12), long-term leg-pain VAS (MD − 0.07, − 0.25 to 0.12), long-term ODI (MD − 0.30, − 0.80 to 0.21), or operation time (MD − 0.26 min, − 8.78 to 8.25). Hospital stay was shorter after UBE (MD − 1.56 days, − 2.78 to − 0.34), although heterogeneity was substantial (I²=93%) and the prediction interval crossed the null. The pooled complication odds favored UBE (OR 0.54, 0.31 to 0.93), but randomized-trial results were imprecise and did not establish a safety difference. Conclusions UBE and microscopic or microendoscopic decompression showed broadly comparable pain and functional outcomes at the prespecified early and long-term assessment windows. The pooled estimate suggested a shorter hospital stay after UBE, but heterogeneity was substantial and the prediction interval crossed the null. Lower pooled complication odds were driven mainly by observational evidence and were not confirmed by the randomized-trial subgroup.