Laparoscopic vs. ultrasound-guided transversus abdominis plane (TAP) block in colorectal surgery: a systematic review and meta-analysis of randomized trials

Background The transversus abdominis plane block (TAPB) is effective for postoperative pain management in patients undergoing colorectal surgery. However, evidence regarding the optimal delivery method, either laparoscopic (L-TAPB) or ultrasound-guided (U-TAPB) is lacking. Our study aimed to compare the effectiveness of these delivery methods. Methods We carried out a literature search of PubMed, Cochrane Library, Web of Science, and Google Scholar databases to include randomized studies comparing patients receiving either L-TAPB or U-TAPB during minimally invasive colorectal surgery. The primary endpoint was opioid consumption in the first 24 h after surgery. Risk of bias was assessed with the RoB-2 tool. Effect size was estimated for each study with 95% confidence interval and overall effect measure was estimated with a random effect model. Results The literature search revealed 294 articles, of which four randomized trials were eligible. A total of 359 patients were included, 176 received a L-TAPB and 183 received a U-TAPB. We established the non-inferiority of L-TAPB, as the absolute difference of -2.6 morphine-mg (95%CI -8.3 to 3.0) was below the pooled non-inferiority threshold of 8.1 morphine-mg (low certainty level). No difference in opioid consumption was noted at 2, 6, 12, and 48 h (low to very low certainty level). Postoperative pain, nausea and vomiting were similar between groups at different timepoints (low to very low certainty level). No TAPB-related complications were recorded. Finally, the length of hospital stay was similar between groups. Conclusion For postoperative multimodal analgesia both L-TAPB and U-TAPB may result in little to no difference in outcome in patients undergoing colorectal surgery. [GRAPHICS] .