The analgesic effect of continuous subacromial bupivacaine infusion after arthroscopic shoulder surgery: a randomized controlled trial.

Background: The benefits of subacromial local anesthetic infusion are controversial. The aim of this study was to evaluate the efficacy of subacromial bupivacaine infusion after arthroscopic acromionplasty and rotator cuff procedures.

Methods: Ninety patients with subacromial impingement disease scheduled for elective shoulder arthroscopy were enrolled in this randomized, prospective and placebo-controlled study. The patients received subacromially either 5.0 mg/ml bupivacaine or 9.0 mg/ml saline at the rate of 2 ml/h post-operatively for 48 h. The primary outcome measure was the use of rescue oxycodone. The consumption of opioids, ibuprofen, paracetamol and codeine, and the intensity of pain were recorded.

Results: Patients receiving bupivacaine infusion used significantly less oxycodone compared with patients receiving saline [15 vs. 20 mg (median) oxycodone intravenously on the day of surgery, 0 vs. 10 mg (median) perorally on the first post-operative day]. There was no significant difference in the use of ibuprofen, paracetamol and codeine, except that paracetamol was used more in patients receiving saline during the day of surgery (P = 0.009). The pain scores of patients receiving bupivacaine were lower at 18 h (P = 0.008). Average pain scores for the worst pain experienced did not differ between the groups. There were three (4%) premature discontinuations because of technical problems.

Conclusions: Considering the low need of opioids, expenses and technical problems in these patients, subacromial 5.0 mg/ml bupivacaine infusion 2 ml/h confers only moderate and probably clinically insignificant efficacy compared with placebo. This efficacy might be overweighed by the disadvantages.