Efficacy of Erector Spinae Block on Postoperative Outcomes in Bariatric Surgery Patients: A Systematic Review, Meta-Regression, and Trial-Sequential Analysis of Randomized Controlled Trials

Background : Bariatric surgery is effective for severe obesity, but recovery is often complicated by pain, nausea, and high opioid use. This systematic review and meta-analysis (SRMA) evaluates the role of erector spinae plane block (ESPB) in reducing pain, opioid consumption, and postoperative nausea and vomiting (PONV) after bariatric surgery. Methods : The electronic databases were systematically searched from their inception to March 2025 for randomized controlled trials (RCTs) assessing bilateral ESPB in adults undergoing bariatric surgery. This review included studies which compared ESPB to a control group and reported at least one postoperative outcome. The primary outcome was resting pain at 6 hours and 24 hours. The mean difference (MD) and 95% confidence intervals (CI) were calculated for individual studies and pooled using a random-effects model. The meta-regression and trial sequential analysis were performed to evaluate the impact of confounding variables and sample size on the pooled estimate. The risk of bias and certainty of evidence were assessed using the Cochrane Risk of Bias 2 (RoB 2) and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) assessment tools. Results : Twelve RCTs (n = 825; ESPB = 412, control = 413) were included. ESPB significantly reduced resting pain at 6 hours (MD: 1.79; 95% CI: 0.80 – 2.78; p = 0.0004) and 24 hours (MD: 1.09; 95% CI: 0.38–1.79; p = 0.002). Six RCTs (n = 509) reported lower movement-evoked pain at 6 hours (MD:1.28; 95% CI: 0.68–1.88; p < 0.0001) and 24 hours (MD: 0.79; 95% CI: 0.44–1.14; p < 0.0001). Nine RCTs (n = 673) showed reduced 24-hour opioid consumption (MD: 9.0; 95% CI: 2.72 to 15.27, P = 0.005). Five RCTs (n = 448) reported a lower incidence of PONV with ESPB (Risk Ratio: 1.47; 95% CI: 1.08–1.98, p = 0.01). Meta-regression to adjust for baseline confounding factors and trial sequential analysis did not materially alter the results. The risk of bias was low, and the certainty of evidence was rated as moderate to low. Conclusion : This SRMA of RCTs demonstrates that ESPB may significantly reduce postoperative pain, 24-hour postoperative opioid consumption, and PONV compared to control in patients undergoing bariatric surgery. However, further RCTs of adequate power with unified protocols and clearly defined endpoints are warranted.