A Comparison of Combined Suprascapular and Axillary Nerve Blocks to Interscalene Nerve Block for Analgesia in Arthroscopic Shoulder Surgery An Equivalence Study

Background and Objectives: The primary objective of this study was to compare the analgesic efficacy of combined suprascapular and axillary nerve block (SSAX) with interscalene block (ISB) after arthroscopic shoulder surgery. Our hypothesis was that ultrasound-guided SSAX would provide postoperative analgesia equivalent to ISB. Methods: Sixty adult patients undergoing arthroscopic shoulder surgery received either SSAX or ISB prior to general anesthesia, in a randomized fashion. Pain scores, satisfaction, and adverse effects were recorded in the recovery room, 6 hours, 24 hours, and 7 days after surgery. Results: Combined suprascapular and axillary nerve block provided non-equivalent analgesia when compared with ISB at different time points post-operatively, except on postoperative day 7. Interscalene block had better mean static pain score in the recovery room (ISB 1.80 [95% confidence interval [CI], 1.10-2.50] vs SSAX 5.45 [95% CI, 4.40-6.49; P < 0.001]). At 24 hours, SSAX had better mean static pain score (ISB 6.35 [95% CI, 5.16-7.54] vs SSAX 3.92 [95% CI, 2.52-5.31]; P = 0.01) with similar satisfaction between the groups. Conclusions: Combined suprascapular and axillary nerve block provides nonequivalent analgesia compared with ISB after arthroscopic shoulder surgery. While SSAX provides better quality pain relief at rest and fewer adverse effects at 24 hours, ISB provides better analgesia in the immediate postoperative period. For arthroscopic shoulder surgery, SSAX can be a clinically acceptable analgesic option with different analgesic profile compared with ISB.