Percutaneous Endoscopic Lumbar Discectomy for Recurrent Lumbar Disc Herniation: An Updated Systematic Review and Meta-Analysis

OBJECTIVE: This meta-analysis evaluated surgical outcomes following endoscopic or conventional discectomy for recurrent lumbar disc herniation. METHODS: Medline, Cochrane, EMBASE, and Google Scholar were search until October 16, 2016 using these terms: recurrent lumbar disc herniation, endoscopic surgery, and discectomy. Randomized controlled trials (RCTs), prospective, retrospective, and cohort studies were eligible for inclusion. Pooled difference in mean (PDM) with 95% confidence interval (CIs) or relative risks (RRs) were calculated using fixed-effects methods. RESULTS: One RCT and 15 studies were included with a total of 820 patients. Patients received endoscopic surgery experienced shorter operation time than those received conventional surgery (PDM: −52.01, 95% CI: −76.84 to −27.18, P