Pre- or postoperative interscalene block and/or general anesthesia for arthroscopic shoulder surgery: a retrospective observational study.

PURPOSE: Arthroscopic shoulder surgery can be performed with an interscalene brachial plexus block (ISBPB) alone, ISBPB combined with general anesthesia (GA), or GA alone. Postoperative pain is typically managed with opioids; however, both GA and opioids have adverse effects which can delay discharge. This retrospective study compares the efficacy of four methods of anesthesia management for arthroscopic shoulder surgery.

METHODS: Charts of all patients who underwent shoulder surgery by a single surgeon from 2012-2015 were categorized by analgesic regimen: GA only (n = 177), single-shot ISBPB only (n = 124), or pre- vs postoperative ISBPB combined with GA (ISBPB + GA [n = 72] vs GA + ISBPB [n = 52], respectively). The primary outcome measure was the time to discharge from the postanesthesia care unit (PACU).

RESULTS: Mean (SD) time in the PACU ranged from 70.5 (39.9) min for ISBPB only to 111.2 (56.9) min for GA only. Use of ISBPB in any combination and regardless of timing resulted in significantly reduced PACU time, with a mean drop of 27.2 min (95% confidence interval [CI], 17.3 to 37.2; P < 0.001). The largest mean pairwise difference was between GA only and ISBPB only, with a mean difference of 40.7 min (95% CI, 25.5 to 55.8; P < 0.001). Use of ISBPB also reduced pain upon arrival at the PACU and, in some cases, upon discharge from the PACU (i.e., ISBPB only but not ISBPB + GA compared with GA). An ISBPB (alone or prior to GA) also reduced analgesic requirements.

CONCLUSION: Previously reported benefits of an ISBPB for arthroscopic shoulder surgery are confirmed. Postoperative ISBPBs may also be beneficial for reducing pain and opioid requirements and could be targeted for patients in severe pain upon emergence. A sufficiently powered randomized-controlled trial could determine the relative efficacy, safety, and associated financial implications associated with each method.