The efficacy of continuous intrabursal infusion with morphine and bupivacaine for postoperative analgesia after subacromial arthroscopy

Background and Objectives: The aim of this study was to determine whether an intrabursal morphine and bupivacaine mixed infusion provides useful analgesia for prolonged pain relief after subacromial arthroscopic operation. Methods: A continuous intrabursal infusion catheter was inserted at the conclusion of the subacromial arthroscopic operation that was performed under general anesthesia. in a prospective, double-blind, randomized trial, 60 patients were divided into 2 groups: an anesthetic group received 5 mL of mixed 0.5% bupivacaine, 2 mg of morphine, 0.05 mL of 1/1,000 epinephrine as a bolus, and a solution of 40 mL of a 0.5% bupivacaine and 8 mg of morphine mixture that was used as a maintenance dose at a constant rate of 0.5 mL/h. This was done by means of a continuous infusion pump (0.5 mL hourly). A saline group (n = 30) received continuous saline infusion. Two patients were eliminated from the study because of catheter leakage or malfunction in the saline group. The intensity of the pain was evaluated preoperatively and postoperatively for 3 days by a graded visual analog scale (score from 0 to 10) for night pain, pain on motion, sleep disturbance, lying on painful shoulder, and the amounts of supplemental analgesics. Results: Pain was decreased on the first and second postoperative day, and there was less sleep disturbance for 3 days postoperatively in the anesthetic group. There was no difference in pain caused by movement postoperatively. In the anesthetic group, lesser amounts of analgesics were used in the first 48 hours postoperatively. Conclusions: The continuous intrabursal infusion method resulted in a decreased perception of rest pain and reduced supplemental analgesics requirement for 2 days postoperatively.