Efficacy of transversus abdominis plane block in preventing chronic postsurgical pain: a systematic review and meta-analysis

Background: The prevalence of chronic postsurgical pain (CPSP) ranges from 10% to 50%, varying by surgical procedure. With over 300 million surgeries performed annually worldwide, the prevention and management of CPSP represent a significant clinical challenge. Objective: This systematic review and meta-analysis aimed to evaluate the efficacy of transversus abdominis plane (TAP) block in reducing the prevalence of CPSP among adults undergoing abdominal surgery. Methods: We searched PubMed, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, ChinaInfo, and CNKI from their inception to July 2025. We included randomized controlled trials (RCTs) comparing TAP block with no block or placebo in adults (≥18 years) undergoing abdominal surgery. The Cochrane risk of bias tool for randomized trials (RoB 2) was used to assess the risk of bias, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework was used to evaluate the certainty of the evidence. Results: Our systematic search and rigorous screening process identified 8 RCTs involving 630 patients for this meta-analysis. During full-text review, 35 of 43 articles were excluded for specific ineligibility reasons. Low to moderate quality evidence showed that TAP block significantly reduced the prevalence of CPSP at 3, 6 and 12 months postoperatively compared to no TAP block (RR 0.62, 95% CI 0.39 to 0.97, P = 0.04, I 2 = 66% for 3 months, RR 0.44, 95% CI 0.25 to 0.77, P < 0.01, I 2 = 63% for 6 months, RR 0.31, 95% CI 0.13 to 0.74, P < 0.01, I 2 = 0% for 12 months). Very low to low quality evidence demonstrated that TAP block also decreased the pain scores of CPSP at 12 months postoperatively compared to no TAP block (MD −0.18, 95% CI −0.31 to 0.05, P < 0.01, I 2 = 0%), but not at 3 and 6 months postoperatively. The reduction in pain scores observed with TAP block failed to meet the threshold for the minimum clinically important difference (MCID) at all assessed postoperative time points. Moderate quality evidence demonstrated that TAP block significantly reduced the prevalence of postoperative nausea and vomiting (PONV) at 24 hours postoperatively compared to no TAP block (RR 0.56, 95% CI 0.34 to 0.93, P = 0.03, I 2 = 0%). Subgroup analyses provided hypothesis generating evidence that preoperative TAP block significantly reduced the prevalence of CPSP at 3 (RR 0.36, 95% CI 0.24 to 0.56, P < 0.01, I 2 = 0%) and 6 (RR 0.20, 95% CI 0.11 to 0.38, P < 0.01, I 2 = 0%) months postoperatively compared with no block, an effect not seen with postoperative administration. Other subgroup analyses based on local anesthetic type, primary anesthesia method, PCA use, and gender also revealed potential differences. Conclusions: Based on low to moderate certainty evidence, which is limited by significant heterogeneity, TAP block for abdominal surgery may reduce the prevalence of CPSP. This potential benefit appears more pronounced with preoperative administration. However, these findings warrant cautious interpretation. Future large scale, multicenter RCTs designating CPSP as a primary outcome are necessary to provide more definitive evidence.