Comparison of Clinical Efficacy and Postoperative Outcomes of Ultrasound-Guided Lateral Sagittal Infraclavicular and Costoclavicular Brachial Plexus Blocks: A Retrospective Cohort Study

Background/Objectives: The costoclavicular (CCB) and lateral sagittal infraclavicular (ICB) approaches provide ultrasound-guided access to the cords of the brachial plexus. Comparative real-world evidence on imaging efficiency, block dynamics, and postoperative analgesia remains limited. We compared procedural and analgesic outcomes between these approaches. Methods: This retrospective two-center cohort included patients undergoing elective upper-extremity surgery under ultrasound-guided CCB or ICB between April and October 2025. Specialists at both centers had comparable experience with both techniques (approximately 4 years). The primary outcome was total procedure time; secondary outcomes included component times, exact block-onset times recorded during close continuous specialist observation, postoperative pain, rescue analgesia, satisfaction, and discharge time. All patients received the same local-anesthetic dose and volume. Results: Sixty patients were analyzed (29 CCB; 31 ICB). Total procedure time was shorter with ICB (median, 75 vs. 138 s; CCB-ICB Hodges–Lehmann median difference, 65 s; 95% CI, 23–110 s; p < 0.001), as were imaging and application times. Motor- and total-block onset were faster with ICB, whereas sensory-block onset did not differ significantly. Pain scores at 6, 12, and 24 h, rescue analgesia, analgesia duration, satisfaction, and discharge time did not differ significantly. Hemidiaphragmatic paralysis is generally asymptomatic and was not systematically assessed; no local anesthetic systemic toxicity occurred. Conclusions: ICB was associated with statistically shorter procedural and selected block-onset times than CCB. However, the absolute difference in total procedure time was modest, and its clinical importance remains uncertain. The absence of corresponding differences in sensory-block characteristics and patient-centered postoperative outcomes means that these findings should not be interpreted as demonstrating the overall clinical superiority of ICB. Prospective randomized studies incorporating predefined clinically important differences and adequately powered patient-centered outcomes are required.