Assessment of pain relief provided by interscalene regional block and infusion pump after arthroscopic shoulder surgery

Abstract

Purpose: This study was performed to evaluate the efficacy of interscalene regional blocks and infusion pumps for postoperative pain control after arthroscopic subacromial decompression with or without arthroscopic rotator cuff repair.

Methods: Seventy-six patients were included in the prospective study. Participants were randomized into 4 treatment groups: (1) interscalene regional block, (2) infusion pump with 0.5% bupivacaine, (3) interscalene block combined with an infusion pump containing 0.5% bupivacaine, and (4) interscalene block combined with an infusion pump containing 0.9% saline solution. The interscalene regional block was performed with a nerve stimulator. Infusion pump catheters were positioned in the subacromial space. Visual analog scale (VAS) data were collected preoperatively, at 1 and 2 hours postoperatively, and daily for an additional 6 days postoperatively. An analysis of variance with a Student-Newman-Keuls post hoc test was used to identify statistically significant (P < .05) differences in VAS scores between the groups at each time point. Percentages of patients who took medication for pain management in the recovery room were compared between the 4 groups by use of chi(2) analysis.

Results: Significant differences were noted in VAS scores postoperatively. Group 2 (pump only) had significantly higher scores than all other groups for the first 2 hours. Furthermore, group 4 (block and pump filled with saline solution) had significantly lower VAS scores than group 1 (block only) at 1 hour. This difference was no longer significant by the second hour. The percentage of patients who required oral narcotics or intravenous pain medication was significantly larger for group 2 than for the other groups.

Conclusions: The interscalene regional block provided more pain relief than infusion pumps immediately after arthroscopic shoulder surgery. Infusion pumps did not significantly reduce pain levels after the blocks wore off.

Level of evidence: Level II, prospective comparative therapeutic study.