Randomized comparison between interscalene and combined infraclavicular-anterior suprascapular nerve blocks for arthroscopic shoulder surgery

Background This randomized trial compared ultrasound-guided interscalene block (ISB) and combined infraclavicular (ICB)-anterior suprascapular nerve block (SSNB) for arthroscopic shoulder surgery. We hypothesized that combined ICB-anterior SSNB provides equivalent analgesia to ISB 30 min after surgery. Methods Fifty subjects were randomized to ISB or combined ICB-anterior SSNB. Twenty mL of bupivacaine 0.5% with epinephrine 5 µg/mL was used for ISB. For ICB and anterior SSNB, we administered 20 mL and 3 mL of bupivacaine 0.5% with epinephrine 5 µg/mL, respectively. Subsequently, all patients underwent general anesthesia. The primary outcome was the pain score at 30 min in the post-anesthesia care unit. Secondary outcomes included the rate of complete sensorimotor blockade (assessed after the performance of the blocks using a 14-point composite scale), postoperative pain scores at 0.5, 1, 3, 6, 12, 24, 36, and 48 hours, the presence of hemidiaphragmatic paralysis at 30 min after the performance of the blocks and in the post-anesthesia care unit, consumption of intraoperative and postoperative narcotics, opioid-related side effects, and patient satisfaction at 24 hours. Results No intergroup differences were found in postoperative pain scores, proportion of patients with complete sensorimotor blockade, intraoperative/postoperative opioid consumption, side effects, and patient satisfaction at 24 hours. Compared with combined ICB-SSNB, ISB resulted in a higher incidence of hemidiaphragmatic paralysis 30 min after the block and in the post-anesthesia care unit (68% vs 0%; and 88% vs 0%, respectively; both p<0.001). Conclusion Compared with ISB, combined ICB-anterior SSNB results in equivalent postoperative analgesia while circumventing the risk of hemidiaphragmatic paralysis. Further confirmatory trials are required. Future studies should also investigate whether combined ICB- anterior SSNB can provide surgical anesthesia for shoulder surgery. Trial registration number NCT05444517 .