Evaluation of postoperative analgesic efficacy of transversus abdominis plane block after abdominal surgery: A comparative study

Background: The transversus abdominis plane (TAP) block is an effective method of providing postoperative analgesia in patients undergoing midline abdominal wall incisions, by blocking the abdominal wall neural afferents via the bilateral lumbar triangles of Petit. We evaluated its analgesic efficacy in patients during the first 48 postoperative hours after abdominal surgery, in a randomized, controlled single-blind clinical trial. Materials and Methods: Sixty patients (mean age 36.2 ± 9.6 years) of either sex of ASA grade 1 and 2 who underwent major gynecological or surgical operation were randomized either to receive standard care, including patient-controlled tramadol analgesia ( n = 30), or to undergo TAP block ( n = 30) in addition to standard care. After completion of surgery, 20 ml of 0.375% levobupivacaine was deposited into the transversus abdominis neurofascial plane via the bilateral lumbar triangles of Petit. Each patient was assessed in the postanesthesia care unit and at 2, 4, 6, 12, 24, and 48 h postoperatively. Results: The TAP block reduced Visual Analog Scale pain scores at most (2, 4, 6, 12, 24 h), but not at all time (36, 48 h) points assessed. Patients undergoing TAP block had reduced tramadol requirement in 24 h (210.05 ± 20.5 vs. 320.05 ± 10.6; P < 0.01) and 48 h (508.25 ± 20.6 vs. 550.25 ± 20.6; P < 0.01), and a longer time to the first PCA tramadol request (in minutes), compared to the control group (178.5 ± 45.6 vs. 23.5 ± 3.8; P < 0.001). Conclusion: The TAP block provided highly effective postoperative analgesia in the first 24 postoperative hours after major abdominal surgery, and no complications due to the TAP block were detected.