Retroclavicular vs Infraclavicular block For Upper Limb Anesthesia: A Multi-Centric Randomized Trial

Background: The coracoid approach is a simple method to perform ultrasound-guided brachial plexus regional anesthesia (RA) but its simplicity is counterbalanced by a difficult needle visualization. We hypothesized that the retroclavicular (RCB) approach is not longer to perform when compared to the coracoid (ICB) approach, and improves needle visualization. Methods: This randomized, controlled, non-inferiority trail conducted in two hospitals, included patients undergoing distal upper limb surgery. Patients were randomly assigned to a brachial plexus block (ICB or RCB). The primary outcome was performance time (sum of visualization and needling time), and was analyzed with a non-inferiority test of averages. Depth of sensory and motor blockade, surgical success, total anesthesia time, needle visualization, number of needle passes and complications were also evaluated. Subgroup analysis restricted to patients with higher body mass index was completed. Results: We included 109 patients between September 2016 and May 2017. Mean RCB performance time was 7.1% shorter than ICB (retro: 4.8 ± 2.0 min; infra: 5.2 ± 2.3 min, p=0.06) with a 95% CI reaching up to 5.8% longer. RCB conferred an ultrasound-needle angle closer to 0° and significantly improved needle visibility after the clavicle was cleared and before local anesthetic administration. No differences were found in the secondary outcomes. Similar results were found in the subgroup analysis. Conclusion: In patients undergoing distal upper limb surgery with an infraclavicular anesthesia, performance time with RCB approach was deemed clinically similar to ICB approach while improving needle visibility. Clinical Trial Registration: ClinicalTrials.gov (NCT02913625), registered 26 September 2016