Transversus Abdominis Plane Block Does Not Provide Additional Benefit to Multimodal Analgesia in Gynecological Cancer Surgery

Abstract

The transversus abdominis plane (TAP) block is a recently described technique involving injecting local anesthetic between the internal oblique and transversus abdominis layers of the abdominal wall. It has been shown to be effective in reducing morphine consumption and improving postoperative pain relief in several clinical settings. We performed a randomized placebo-controlled trial comparing bilateral ultrasound-guided TAP blocks (2 x 20 mL 0.5% ropivacaine or 0.9% saline) in adult female patients undergoing midline laparotomy for known or presumed gynecological malignancy. Both groups received multimodal IV analgesia. The primary outcomes for the study were defined as the incidence of "inadequate" analgesia (defined as a score >50 mm on a visual analog scale) with forced expiration at 2 hours postoperatively and total postoperative morphine consumption at 2 hours and 24 hours. Data from 65 patients were included in the study. The groups were comparable in terms of age, weight, surgical duration, and intraoperative morphine doses. There were no significant differences between the control and treatment groups in the proportion of patients with inadequate analgesia either at rest (39% vs. 22%, P = 0.13) or with coughing (61% vs. 53%, P = 0.54) at 2 hours. There was no significant difference in postoperative morphine consumption between the placebo and treatment groups at 2 hours (13.5 mg vs. 11.87 mg, P = 0.53) or 24 hours (34.0 mg vs. 36.1 mg, P = 0.76). There were no significant differences in the incidence of opioid side effects or patient satisfaction. This study demonstrated that TAP blockade conferred no benefit in addition to multimodal analgesia in women undergoing major gynecological cancer surgery.