Percutaneous endoscopic interlaminar discectomy vs. percutaneous endoscopic transforaminal discectomy for L5/S1 lumbar disc herniation: a systematic review and meta-analysis of randomized controlled trials.

Background: L5/S1 lumbar disc herniation (LDH) presents distinctive anatomical constraints that may influence the choice of operative corridor during full-endoscopic surgery. This updated systematic review and meta-analysis compared the perioperative efficiency, clinical outcomes, and safety of percutaneous endoscopic interlaminar discectomy (PEID) and percutaneous endoscopic transforaminal discectomy (PETD) using randomized evidence focused on single-level L5/S1 LDH. Methods: We conducted a systematic review and meta-analysis in accordance with the PRISMA 2020 statement. PubMed, Embase, Cochrane CENTRAL, Web of Science, CNKI, and Wanfang were searched from inception to June 11, 2026. Randomized controlled trials with verifiable randomized allocation directly comparing PEID and PETD for single-level L5/S1 LDH were included. Continuous outcomes were synthesized as mean differences (MD), and dichotomous outcomes were synthesized as risk ratios (RR) or risk differences (RD), each with 95% confidence intervals (CI). ODI and VAS outcomes were analyzed according to specific follow-up time points. Fluoroscopy was analyzed separately as exposure duration in seconds or frequency counts. Risk of bias was assessed using RoB 2, and certainty of evidence was evaluated using GRADE. Results: Thirteen studies involving 1,059 patients were included. PEID was associated with shorter operative time than PETD (12 studies; MD = -17.07 min, 95% CI -26.05 to -8.09; I2 = 98.7%). Fluoroscopy frequency favored PEID (10 studies; MD = -8.94 counts, 95% CI -11.40 to -6.48; I2 = 99.6%), whereas fluoroscopy exposure duration reported in seconds did not show a statistically significant difference (2 studies; MD = -3.70 s, 95% CI -8.01-0.61; I2 = 99.1%). No robust between-group difference was observed for hospital stay (9 studies; MD = 0.38 days, 95% CI -0.36-1.12). VAS leg pain and ODI were generally comparable across follow-up time points. Modified MacNab excellent/good rates were also comparable between approaches (9 studies; RR = 1.01, 95% CI 0.98-1.04; I2 = 0%). Complications/adverse events did not differ significantly (9 studies; RD = 0.008, 95% CI -0.019-0.035; I2 = 0%). Conclusions: The updated evidence suggests that PEID may be associated with shorter operative time and reduced fluoroscopy frequency compared with PETD for L5/S1 LDH, but the magnitude of these perioperative effects remains uncertain because of very high between-study heterogeneity. However, postoperative pain relief, functional recovery, global clinical success, and safety outcomes appear broadly comparable. Given methodological limitations, geographic concentration of studies, and substantial heterogeneity in several outcomes, these findings should be interpreted cautiously, and procedure selection should remain individualized. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD420251207128, identifier CRD420251207128.