Intraperitoneal Local Anesthetic Instillation for Post‐Operative Pain Control After Bariatric Surgery: A Systematic Review and Meta‐Analysis of Randomized Controlled Trials

Background Postoperative pain after bariatric surgery is a significant clinical challenge, with approximately 61.4% of patients reporting persistent pain. Intraperitoneal local anesthetic instillation (IPLA) has been proposed as a strategy to reduce pain and opioid‐related adverse effects. However, as its effectiveness in bariatric procedures remains controversial, this meta‐analysis was conducted to clarify the role of IPLA in this setting. Methods This systematic review and meta‐analysis was conducted following PRISMA guidelines and was prospectively registered in PROSPERO. We performed a comprehensive search in Pubmed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science for randomized controlled trials (RCTs) IPLA instillation with a control group in patients undergoing bariatric surgery. The primary outcomes were postoperative pain intensity, need for rescue analgesia, and supplementary opioid consumption. Secondary outcomes included postoperative nausea and vomiting (PONV), nausea, vomiting, and shoulder pain. Data were synthesized using a random‐effects model to calculate Risk Ratios (RR) for binary outcomes and Standardized Mean Differences (SMD) and Mean Differences (MD) for continuous outcomes. The methodological quality of the trials was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool. Results The analysis included 13 randomized controlled trials with a total of 1205 participants, of whom 624 were in the intraperitoneal local anesthetic (IPLA) group and 581 were in the control group. The pooled results showed that IPLA significantly reduced postoperative pain intensity (SMD: −0.96, 95% CI −1.72 to −0.20; p = 0.01) and the need for rescue analgesia (RR: 0.52, 95% CI 0.31–0.89). However, there was no significant difference in postoperative opioid consumption (SMD: −0.56, 95% CI −1.13 to 0.01; p = 0.05). Additionally, no significant effects were found for the incidence of postoperative nausea and vomiting (PONV) or shoulder pain. High heterogeneity was noted in most of the analyses. Conclusion IPLA reduces postoperative pain in bariatric surgery but does not decrease opioid consumption or adverse events. A suggested reduction in rescue analgesia was not robust. Due to high heterogeneity, the findings' clinical applicability is limited, highlighting the need for standardized trials. Trail Registration PROSPERO protocol CRD420251085223—July 2025