Transversus abdominis plane block versus local anaesthetic wound infiltration for postoperative analgesia: A systematic review and meta-analysis.

BACKGROUND Transversus abdominis plane (TAP) block and local anaesthetic wound infiltration can provide effective pain relief at the wound site after surgery. However, the relative efficacy of two techniques for postoperative analgesia remains controversial. METHODS We searched PUBMED, EMBASE and CENTRAL databases for randomized controlled trials (RCTs) comparing TAP block with wound infiltration for pain relief after surgery. The primary outcomes were pain scores at rest and on movement at 1, 8 and 24 hours postoperatively and cumulative morphine consumption over 24 hours. The secondary outcomes were time to first rescue analgesic, number of rescue analgesic use and opioids-related side-effects. RESULTS Nine RCTs with a total of 500 participants were included. TAP block was associated with significant lower rest and dynamic pain scores at 8 hour [MD = -1.08, 95% CI (-1.89-0.26), P = 0.009] and 24 hour [MD = -0.83, 95% CI (-1.60, -0.06), P = 0.03] postoperatively than wound infiltration, but no significant difference was found at 1 hour [MD = -0.94, 95% CI (-1.97, 0.09), P = 0.08] postoperatively. In adults, TAP block significantly reduced 24-hour overall morphine consumption by 3.85 mg [MD = -3.85, 95% CI (-7.47, -0.22), P = 0.04] compared with wound infiltration. Subgroup analysis showed that adults received TAP block appeared to have lower rest pain scores at 24 hour than children (P = 0.008). CONCLUSION TAP block provides superior analgesia compared with wound infiltration in the setting of a multimodal analgesic regimen. Subgroup analysis indicated that adults may have benefits additional to the analgesic effect than children.