Please confirm that an ethics committee approval has been applied for or granted: Yes: I’m uploading the Ethics Committee Approval as a PDF file with this abstract submission

Background and Aims Arthroscopic shoulder repair (ASR) is less invasive than open surgery, yet perioperative pain management poses challenges. While the interscalene brachial plexus block is effective, its complications drive exploration of alternative techniques. Studies demonstrate analgesic efficacy of sub-omohyoid plane (SOP) block and combinations of infraclavicular brachial plexus block (costoclavicular approach, CC) with superficial cervical plexus (SCP) block comparable to interscalene block. Our study aims to compare their analgesic efficacy, pain scores, complications, and block properties.

Methods This assessor-blinded study (January 2023 - May 2024) involved ASA I-III patients (aged 18-75) undergoing ASR, (NCT05683522). Both groups received blocks pre-surgery: SOP block with 15 mL of 0.25% bupivacaine; combination block with 20 mL for CC and 10 mL for SCP. The primary outcome was 24-hour morphine consumption. Secondary outcomes included NRS scores, time to first opioid request, and complications. Quality of recovery-15 scores were also documented.

Results In this study consisting of 61 patients (SOP: 31, CC+SCP: 30), no significant difference was found in morphine consumption, pain scores and QoR scores (p>0.05). Time to first analgesia request was shorter in the SOP group than CC+SCP group (490±393 vs 280±256 minutes, respectively; p: 0.015),(table 1-2). Hemi-diaphragmatic paralysis was not observed, however, Horner syndrome was noted in only 1 patient in SOP group.

Conclusions Ultrasound guided SOP block and CC+SCP blocks were similar in terms of analgesic consumption and pain scores in ASR, and the number of complications was almost non-existent. The SOP group caused less forearm motor block and may be more operator-friendly due to its single injection.