Comparison between ultrasound-guided versus laparoscopic-guided transversus abdominis plane block on postoperative pain and morphine consumption

A prospective, randomized, single-blinded non-inferiority clinical trial was conducted with patients undergoing elective laparoscopic colectomy for colon cancer. Eighty patients were randomly assigned (1:1 ratio) to the UTAP and LTAP groups. At the end of the operation, opioid consumption and numeric rating scores (NRS; 0 [no pain] to 10 [worst pain]) of pain were recorded at 2, 6, 24, and 48 hours postoperatively and were compared between the groups. The primary end point was pain NRS during rest at 24 hours after operation. Thirty-eight patients in the LTAP group and 35 patients in the UTAP group completed the study protocol. We found no significant difference in mean ± SD pain NRS during rest at 24 hours between the LTAP group (3.90 ± 1.7) and the UTAP group (4.5 ± 1.9). The mean difference in pain NRS during rest at 24 hours was 0.57 (95% CI -0.26 to 1.41). Because the lower boundary of a 95% CI for the differences in pain NRS was > -1, non-inferiority was established. There was no significant difference between the groups in NRS pain during rest, NRS pain on movement, and postoperative morphine consumption during the 48 hours after operation. These results show our new LTAP block technique was non-inferior to the ultrasound-guided technique in providing a TAP block after laparoscopic colorectal operation.