The aim of the study was to compare the analgesic efficacy of epidural analgesia and transverse abdominis plane (TAP) block. TAP block has gained popularity to provide postoperative analgesia after abdominal surgery but its advantage over epidural analgesia is disputed.
We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. Only trials comparing TAP block with epidural analgesia were included. The primary outcome was pain score at rest (analog scale, 0-10) on postoperative day 1 analyzed in subgroups according to the population (children and adults). Secondary outcomes included rate of hypotension, length of stay, and functional outcomes (time to first bowel sound, time to first flatus).
Ten controlled trials, including 505 patients (195 children and 310 adults), were identified. Pain scores at rest on postoperative day 1 were equivalent for TAP block and epidural analgesia groups in children (mean difference: 0.3; 95% confidence interval [CI]: -0.1 to 0.6; I = 0%; P = .15) and in adults (mean difference: 0.5; 95% CI: -0.1 to 1.0; I = 81%; P = .10). The quality of evidence for our primary outcome was moderate according to the GRADE system. The epidural analgesia group experienced a higher rate of hypotension (relative risk: 0.13; 95% CI: 0.04-0.38; I = 0%; P = .0002), while hospital length of stay was shorter in the TAP block group (mean difference: -0.6 days; 95% CI: -0.9 to -0.3 days; I = 0%; P < .0001), without impact on functional outcomes.
There is moderate evidence that TAP block and epidural analgesia are equally effective in treating postoperative pain in both pediatric and adult patients, while TAP block is associated with fewer episodes of hypotension and reduced length of stay.