Comparison of posterior and subcostal approaches to ultrasound-guided transverse abdominis plane block for postoperative analgesia in laparoscopic cholecystectomy

Study objective: To evaluate the effectiveness of subcostal TAP block and to compare its efficacy with that of posterior TAP block in decreasing postoperative pain in patients undergoing laparoscopic cholecystectomy during general anesthesia.

Design: Prospective, randomized, double-blind study.

Setting: Academic medical center.

Patients: 60 adult, ASA physical status 1 and 2 patients of both genders, aged 18-60 years, scheduled for elective laparoscopic cholecystectomy.

Interventions: Patients were randomized to three groups of 20 patients each. Group 1 patients received standard general anesthesia (control group); Group 2 patients received an ultrasound-guided posterior TAP block using 15 mL of 0.375% ropivacaine on each side; and Group 3 patients underwent a subcostal TAP block with 15 mL of 0.375% ropivacaine on each side.

Measurements: The presence and severity of pain during rest and movement, as well as nausea or vomiting and sedation, were assessed in all patients postoperatively on PACU admission, then at 2, 4, 6, 8, 12, and 24-hour intervals. Patients with a visual analog score (VAS) greater than 4, or those requesting analgesic were given intravenous tramadol 2 mg/kg as an initial dose; subsequent 1 mg/kg doses of tramadol, if needed, were given.

Results: Patients who received a subcostal TAP block had significantly lower pain scores at rest and on movement than the control group at all times postoperatively. Although, in the initial postoperative measurement times, the subcostal and posterior TAP groups had comparable pain scores, after 4 hours these scores were significantly lower in patients who had received the subcostal TAP block.

Conclusion: For incisions mainly involving the supra-umbilical region, subcostal TAP block may be a better alternative than the posterior approach for providing postoperative analgesia.