Transversus abdominis plane block for postoperative pain relief after hand-assisted laparoscopic colon surgery: a randomized, placebo-controlled clinical trial

Although hand-assisted laparoscopic surgery (HALS) offers patients smaller surgical incisions, they still experience pain. Currently, there is no consensus on the optimal analgesic package for patients undergoing HALS. The aim of this prospective, randomized, double-blinded, placebo-controlled clinical trial was to evaluate the effect of transversus abdominis plane (TAP) block on postoperative pain control (pain score and analgesic use) and other outcomes in colon cancer patients undergoing hand-assisted laparoscopic left hemicolectomy. Sixty-four patients with colon cancer scheduled for an elective colon resection were enrolled in this study. Patients were randomized into two groups to receive either TAP block using 20 mL of 0.375% ropivacaine (TAP block group: 32 patients) or 20 mL of 0.9% normal saline infusion (placebo group: 32 patients). Anaesthetic and surgical techniques were standardized. Twenty-four-hour postoperative analgesia was maintained by continuous infusion of 0.1-0.9 A mu g/kg/h fentanyl and intravenous injection of ketorolac. The primary outcome of the study was postoperative pain control (pain score and analgesic use). Pain was assessed using numeric rating scale at 2, 4, 8, 12, and 24 h after surgery at rest and during movement. Secondary outcomes included the time to resumption of intestinal function and the length of hospital stay. The data of the two groups were compared using Mann-Whitney U test. All statistical tests were two-tailed at a significance level of 0.05. The patients' mean age was 60.50 +/- 6.77 years, and 68.75% of patients were males. The mean body mass index was 26.23 +/- 4.83 kg/m(2). The TAP block group had lower pain scores after surgery at 2, 4, and 12 h at rest (p < 0.05), at 2 and 4 h during movement (p < 0.01) and used less fentanyl and ketorolac than the placebo group (p < 0.01). The mean time to resumption of intestinal function was shorter in the TAP block group than that in the placebo group (p < 0.0001). The mean length of hospital stay was by 2.7 days shorter in the TAP block group than in the placebo group (p = 0.001). The ultrasound-guided TAP block given during hand-assisted laparoscopic colon surgery as part of a multimodal analgesic regimen is a feasible and effective technique for postoperative analgesia in colon cancer patients and significantly reduces both pain experienced by patients and short-term postoperative analgesic use and promotes early ambulation. Future studies are needed to determine the efficacy and costs/benefits of the ultrasound-guided TAP block in HALS.