A meta-analysis on the clinical effectiveness of transversus abdominis plane block.

STUDY OBJECTIVE: To study the efficacy of the transversus abdominal plane (TAP) block.

DESIGN: Meta-analysis.

SETTING: District general hospital.

PATIENTS: 86 patients in the TAP block group and 88 in the non-TAP block group.

MEASUREMENTS: Statistical analyses were performed using Microsoft Excel 2007 for Windows XP. Hedges g statistic was used for the calculation of standardized mean differences (SMD). Binary data (nausea) were summarized as risk ratios (RR).

MAIN RESULTS: Patients with TAP block required less morphine after 24 hours than those who did not have the block (random effects model: SMD -4.81, 95% CI [-7.45, -2.17], z = -3.57, P < 0.001). There was less time to first request of morphine in the non-TAP block group (random effects model: SMD 4.80, 95% CI [2.16, 7.43], z = 3.57, P < 0.001). Patients in the TAP block group had less pain up to 24 hours postoperatively. No statistical differences were found with respect to nausea.

CONCLUSIONS: TAP block reduces the need for postoperative opioid use, it increases the time first request for further analgesia, it provides more effective pain relief, and it reduces opioid-associated side effects.