Supplementary Material for: Effect of Transversus Abdominis Plane Block on Postoperative Pain after Colorectal Surgery: A Meta-Analysis of Randomized Controlled Trials

<b><i>Objectives:</i></b> To assess the analgesic efficacy of transversus abdominis plane (TAP) block in patients undergoing colorectal surgery (CRS). <b><i>Materials and Methods:</i></b> The databases of PubMed, ISI Web of Science, and Embase were searched, and randomized controlled studies (RCTs) that compared TAP block to control for relief of postoperative pain in patients who underwent CRS were included. Outcomes, including postoperative pain at rest and with movement, morphine use, postoperative nausea and vomiting, and the length of hospital stay, were analyzed using STATA software. The weighted mean differences (WMDs) with 95% confidence intervals (95% CIs) or relative risk with 95% CI were used to present the strength of associations. <b><i>Results:</i></b> A total of 7 RCTs with 511 patients were included. The results of this study suggested that TAP block significantly relieved postoperative pain during postanesthetic recovery after CRS at rest and during movement (WMDs were –0.98 [95% CI –1.57 to –0.38] and –0.68 [–1.07 to –0.30], respectively), and also decreased pain intensity during movement 24 h after CRS (WMD: –0.57 [95% CI –1.06 to –0.08]). TAP block significantly reduced opioid consumption within 24 h when compared to controls, with a WMD of 15.66 (95% CI –23.93 to –7.39). However, TAP block did not shorten the length of hospital stay. <b><i>Conclusions:</i></b> TAP block was an effective approach for relief of postoperative pain and reduced postoperative consumption of morphine. More RCTs with large sample sizes are required to confirm these findings.