Ultrasound‐guided transversus abdominis plane block versus ilioinguinal–iliohypogastric nerve block for postoperative analgesia after open total abdominal hysterectomy: a randomised comparative trial

Summary Open total abdominal hysterectomy is associated with substantial postoperative pain. We compared ultrasound‐guided transversus abdominis plane block with ilioinguinal–iliohypogastric nerve block for postoperative analgesia. We conducted a randomised, parallel‐group trial in patients undergoing elective open total abdominal hysterectomy under general anaesthesia, allocating participants 1:1 to bilateral transversus abdominis plane block or ilioinguinal–iliohypogastric nerve block. The primary outcome was time from end of surgery to first rescue nalbuphine within 24 hours. Secondary outcomes included 24‐hour nalbuphine consumption, pain scores at rest (0–10 numerical rating scale), haemodynamics, postoperative nausea and vomiting and complications. Forty‐two participants were randomised (21 per group). Time to first rescue nalbuphine did not differ significantly between groups (log‐rank p = 0.87; hazard ratio [95% CI] 1.06 [0.45–2.50], p = 0.89). Rescue nalbuphine was required by 11/21 (52%) versus 10/21 (48%) participants (p = 1.00). Total 24‐hour nalbuphine consumption did not differ significantly between groups (median difference [95% CI] 0 [0–3] mg; p = 0.63). Cumulative pain burden over 24 hours was lower with transversus abdominis plane block (median difference [95% CI] −15.3 score [−21.7 to −8.6]; p = 0.0006). Haemodynamic differences were limited to the end of surgery and 5 minutes in the post‐anaesthesia care unit; no significant difference was found in postoperative nausea and vomiting, and no block‐related complications were observed. In summary, transversus abdominis plane block and ilioinguinal–iliohypogastric nerve blocks did not differ in time to first rescue nalbuphine; the study was likely underpowered for this endpoint, and equivalence cannot be inferred. A secondary analysis suggested lower cumulative pain burden with transversus abdominis plane block.