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.