Continuous subacromial bupivacaine infusion for postoperative analgesia after open acromioplasty and rotator cuff repair: preliminary results.

Shoulder surgery is often associated with severe postoperative pain. Previous results in which single or continuous subacromial infiltration of local anesthetics was used as a method of postoperative pain relief have been contradictory. This study was initiated to evaluate the postoperative analgesic effect of a subacromial continuous 0.25% bupivacaine infusion at a rate of 6 mL/h after elective open shoulder surgery. We hypothesized that this procedure would improve postoperative analgesia while reducing morphine requirements. By use of a prospective, double-blind, randomized study design, 50 consecutive patients undergoing acromioplasty and rotator cuff repair surgery received a multiorifice catheter placed in the subacromial space. Twenty patients received 0.25% bupivacaine (group 1), and twenty-two patients received saline solution (group 2). The primary endpoints in the two groups were total morphine consumption administered by patient-controlled analgesia and the patient's subjective pain level evaluated by a visual analog scale during the first 48 postoperative hours. No major technical or pharmacologic side effects were noticed, and the indwelling pain catheter was well tolerated by all patients. There was no statistically significant difference (P < .05) either in total cumulative morphine consumption microg/48 h (73.2 +/- 43.1 vs 60.9 +/- 35.9) or in subjective pain perception 10-point visual analog scale (3.2 +/- 1.4 vs 3.1 +/- 1.5) between the two study groups. The continuous subacromial infiltration of 0.25% bupivacaine at a rate of 6 mL/h is concluded to be ineffective in providing pain relief supplementary to patient-controlled analgesia after open rotator cuff repair and acromioplasty surgery.