Continuous Infusion of a Local Anesthetic Versus Interscalene Block for Postoperative Pain Control After Arthroscopic Shoulder Surgery

Abstract

The purpose of this investigation was to evaluate the efficacy, complication rate, and cost of a 1-time interscalene block compared with a continuous infusion of a local anesthetic for postoperative pain relief in patients having arthroscopic shoulder surgery. After prospective power analysis and institutional review board approval, 56 consecutive patients having arthroscopic shoulder surgery under general anesthesia performed by a single surgeon were randomly assigned to 1 of 2 groups to evaluate postoperative pain control. Group 1 patients received a preoperative interscalene block, and group 2 patients received a subacromial continuous infusion of a local anesthetic (0.5% bupivacaine) via a pain pump for 48 hours postoperatively. Pain was evaluated at 12, 24, 36, and 48 hours and then daily on postoperative days 3 through 7 by use of a visual analog scale included in a patient diary. Patients were provided with 2 "rescue" medication options: ibuprofen and Percocet (Endo Pharmaceuticals, Chadds Ford, PA). The total number of tablets ingested was also evaluated over these same intervals. Total hospital outpatient surgical costs for each group were calculated by dividing total hospital charges by the ratio of annual hospital cost to charges. No statistically significant differences were identified between the 2 groups with regard to visual analog scale pain scores, medication intake, or cost. Complications did not occur in either group. One patient inadvertently removed the pain pump catheter. Our results support the null hypothesis. We found no difference between interscalene block versus continuous subacromial infusion of a local anesthetic with regard to efficacy, complication rate, or cost. Level I, prospective, randomized controlled trial.