Evaluation of Transversus Abdominis Plane (TAP) Block in Hernia Surgery: A Meta-analysis.

BACKGROUND:Transversus abdominis plane (TAP) block reduces opiate requirements and pain scores in abdominal surgery, but the effect has not been evaluated in hernia surgery. The aim of this study was to evaluate the efficacy of TAP block in hernia surgery. METHODS:A meta-analysis of randomized clinical trials (RCTs) evaluating the effect of TAP block in adults undergoing hernia surgery was performed. The primary outcomes were morphine requirements 24 hours after surgery and the number of rescue analgesia patients. Secondary outcomes were pain scores on rest and on movement at 24 hours after surgery, postoperative nausea and vomiting and general postoperative complications. RESULTS:The search strategy yielded 231 articles after duplicates have been removed, and finally 8 RCTs with a total of 791 patients were included. In patients who received a TAP block, the cumulative morphine utilization was significantly reduced at 24 hours (weighted mean difference [WMD] -11.40 mg, -22.41 to -0.39; P=0.04). The number of patients needing a rescue analgesia (relative risk: 0.35, 0.22 to 0.55; P<0.001), the pain scores on rest 24 hours after surgery (WMD: -0.29, -0.55 to -0.04; P=0.02) and the pain scores on movement or coughing 24 hours after surgery (WMD: -0.70, -1.33 to -0.06; P=0.03) were all lower in patients who received a TAP block. There was also significant reduction in the postoperative nausea and vomiting, and the general postoperative complications in TAP block group. CONCLUSIONS:Within a heterogeneous group of RCTs, TAP block reduces postoperative morphine requirements and the severity of pain after hernia surgery.