The Analgesic Efficacy of Transversus Abdominis Plane Block Vs. Wound Infiltration after Inguinal and Infra-Umbilical Hernia Repairs

BACKGROUND Both transversus abdominis plane (TAP) block and wound infiltration with local anaesthetic have been used to relieve pain after inguinal or infra-umbilical hernia repair. OBJECTIVES To determine whether TAP block or local anaesthetic infiltration is the best analgesic option after inguinal or infra-umbilical hernia repair. DESIGN Systematic review and meta-analysis with trial sequential analysis. DATA SOURCES MEDLINE, Embase, Cochrane Central Register of Controlled Clinical Trials, Web of Science, up to June, 2020. ELIGIBILITY CRITERIA We retrieved randomised controlled trials comparing TAP block with wound infiltration after inguinal or infra-umbilical hernia repair. Primary outcome was rest pain score (analogue scale 0 to 10) at 2 postoperative hours. Secondary pain-related outcomes included rest pain score at 12 and 24 h, and intravenous morphine consumption at 2, 12 and 24 h. Other secondary outcomes sought were block-related complications such as rates of postoperative infection, haematoma, visceral injury and systemic toxicity of local anaesthetic. RESULTS Seven trials including 420 patients were identified. There was a significant difference in rest pain score at 2 postoperative hours in favour of TAP block compared with wound infiltration, with a mean (95% confidence interval) difference of −0.8 (−1.3 to -0.2); I 2 = 85%; P = 0.01. Most secondary pain-related outcomes were also significantly improved following TAP block. No complication was reported. The overall quality of evidence was moderate. CONCLUSION There is moderate level evidence that TAP block provides superior analgesia compared with wound infiltration following inguinal or infra-umbilical hernia repair. TRIAL REGISTRY NUMBER PROSPERO CRD42020208053.