Transversus abdominis plane block using a short-acting local anesthetic for postoperative pain after laparoscopic colorectal surgery: a systematic review and meta-analysis

Background Transversus abdominis plane (TAP) block using a short-acting local anesthetic as part of multimodal analgesia is efficient in various abdominal surgeries, including laparoscopic surgery. However, information regarding its use in laparoscopic colorectal surgery is still limited and sometimes controversial. Therefore, we conducted a systematic review and meta-analysis to determine whether TAP block using a short-acting anesthetic has a positive postoperative analgesic outcome in patients who have undergone laparoscopic colorectal surgery. Methods We searched for studies comparing the postoperative pain outcome after laparoscopic colorectal surgery between patients who received TAP block and a control group (placebo or no treatment). Outcome measures were early pain at rest (numeric rating scale [NRS] score at 0-2 h postoperatively), late pain at movement (NRS score at 24 h postoperatively), late pain at rest (NRS score at 24 h postoperatively), and postoperative opioid consumption (up to 24 h postoperatively). We used a random-effects model for the meta-analysis and Egger's regression test to detect publication bias. Results We included six studies involving 452 patients (224 in the TAP block group, 228 in the control group). Early and late pain scores at movement were significantly different between the TAP block and control groups (standardized mean difference: - 0.695, P < 0.0001 for early pain and - 0.242, P = 0.029 for late pain). There was no significant difference between the TAP block and control groups in early pain at rest (P = 0.475), late pain at rest (P = 0.826), and postoperative opioid consumption (P = 0.257). Conclusions The TAP block using a short-acting anesthetic had a significant effect on the postoperative pain outcome in the early (0-2 h) and late (24 h) period at movement. However, it did not have a significant effect on the postoperative pain outcome in the early (0-2 h) and late (24 h) periods at rest after laparoscopic surgery.