Efficacy and safety of unilateral biportal endoscopy for recurrent lumbar disc herniation: A quantitative analysis of 7 cohort studies involving 409 patients.

To systematically evaluate the clinical efficacy and safety of unilateral biportal endoscopy (UBE) in the treatment of recurrent lumbar disc herniation (rLDH). PubMed, Embase, and the Cochrane Library were systematically searched for clinical studies investigating UBE for rLDH published up to November 29, 2025. Study selection, data extraction, and quality assessment were independently performed by two reviewers. Study quality was evaluated using the Newcastle-Ottawa Scale (NOS). Meta-analysis was conducted using Stata version 18.0. Continuous variables were pooled using standardized mean differences (SMDs) or weighted mean differences (WMDs) with corresponding 95% confidence intervals (CIs). Exploratory subgroup analyses were performed to assess potential sources of heterogeneity. Statistical heterogeneity was assessed using the I² statistic. Publication bias was evaluated using Egger's test and the trim-and-fill method. A total of seven high-quality retrospective cohort studies (all with NOS scores ≥ 8) involving 409 patients with rLDH were included. Compared with preoperative values, UBE significantly improved postoperative visual analogue scale scores for back pain (VAS-BP) (immediate postoperative: SMD = - 3.59, 95% CI: -4.81 to - 2.37; final follow-up: SMD = - 5.01, 95% CI: -7.24 to - 2.78), leg pain (VAS-LP) (immediate postoperative: SMD = - 3.76, 95% CI: -5.78 to - 1.75; final follow-up: SMD = - 5.72, 95% CI: -7.65 to - 3.79), and Oswestry Disability Index (ODI) scores (immediate postoperative: SMD = - 4.20, 95% CI: -6.64 to - 1.75; final follow-up: SMD = - 4.44, 95% CI: -6.55 to - 2.34) (all p < 0.001). Perioperative outcomes demonstrated a mean operative time of 99.59 min (95% CI: 72.15 to 127.03), a mean intraoperative blood loss of 66.59 mL (95% CI: 44.14 to 89.03), and a mean length of hospital stay of 4.54 days (95% CI: 3.22 to 5.86). The overall complication rate was 4% (risk difference (RD) = 0.04, 95% CI: 0.02 to 0.05). Although substantial heterogeneity was observed across most outcomes (I² > 96%), sensitivity analyses confirmed the robustness of the pooled results. Publication bias was detected in certain outcomes; however, after adjustment using the trim-and-fill method, the primary efficacy outcomes remained statistically significant. This meta-analysis suggests that UBE may provide favorable clinical efficacy and an acceptable safety profile in the treatment of rLDH. Significant postoperative improvements were observed in back and leg pain as well as functional outcomes, with a relatively low rate of complications. These findings support UBE as a promising minimally invasive surgical option for rLDH.