A prospective randomized trial comparing the efficacy of temperature-responsive gel with local anesthetics versus local anesthetic infusion pump device for postoperative pain control after bariatric surgery.

Purpose: Bariatric surgery is the gold standard for the treatment of morbid obesity, but postoperative pain impedes recovery. Currently available pain-recovery treatments have patient safety concerns. This led to a noninferiority study of Welpass (Genewel Co., Ltd.) vs. On-Q PainBuster (B. Braun), each used alongside a traditional method of continuous local anesthetic administration, in patients undergoing bariatric surgery.

Methods: In this single-center prospective randomized clinical trial, patients were assigned in a 1:1 ratio to the treatment group (Welpass) and the control group (On-Q PainBuster), with ketorolac administered as needed after surgery according to the protocol. To assess efficacy, the total amount of ketorolac used up to 72 hours postoperatively was measured. Additionally, ketorolac usage and numerical rating scales (NRS) were recorded at 6, 24, 48, and 72 hours after operation.

Results: The total amounts of ketorolac used in the 72 hours postoperatively were 188.0 ± 84.6 mg in the treatment group and 198.7 ± 50.0 mg in the control group. The efficacy of the treatment group was noninferior to that of the control group, since the lower limit (-29.9 mg) of the confidence interval for the difference with the control group was greater than the prespecified noninferiority margin (-35.0 mg). Furthermore, when the NRS was evaluated after bariatric surgery, there was no significant difference in scores between the 2 groups at each time point (P > 0.05).

Conclusion: We found no difference in effect on pain between the 2 groups, supporting the use of Welpass in clinical practice for pain management in patients undergoing bariatric surgery.