Transversus abdominis plane block for postoperative analgesia after laparoscopic surgery: a systematic review and meta-analysis.

Background: The increasing use of the transversus abdominis plane (TAP) block, as a form of pain relief after laparoscopic surgery, warrants evaluation of its effectiveness, when compared with other analgesic techniques.

Methods: We searched online databases of MEDLINE, EMBASE, Google scholar and The Cochrane Database of Systematic Review. Mean differences (MD) were formulated for continuous data; odds ratios (OR) were calculated for dichotomous data. Results were produced with a random effects model with 95% confidence intervals (CI).

Results: 14 trials with a total of 905 patients were included for the analysis, TAP block resulted in significantly less postoperative analgesic consumption at 24 h (MD = -25.46, 95% CI [-32.22, -18.69], P < 0.00001), and less number of patients requiring analgesic postoperatively (OR = 0.16, 95% CI 0.03-0.87, P = 0.03). Meanwhile, pain sores were significantly different at 2 h (MD = -1.55, 95% CI [-2.50, -0.59], P < 0.00001), a borderline difference between the groups seen at 6 hours ( MD = -1.13, 95% CI [-1.69, -0.56], P = 0.05), and there was not affect pain at 24 h (MD = -0.33, 95% CI [-0.08, 0.15], P = 0.14) with TAP block groups compared with the groups without TAP block. There was a significant difference in postoperative nausea and vomiting (random effects model: OR = 2.04, 95% CI [1.19-3.48], P = 0.34).

Conclusion: TAP block would result in less analgesic consumption, less requirement of analgesic, and less pain at 2 h and slightly at 6 h but at 24 h after laparoscopic surgery in comparison with usual care alone or placebo block. In addition TAP block can increase the incidence of postoperative nausea and vomiting.