Perineural versus Perivascular Ultrasound-Guided Axillary Brachial Plexus Block for Elective Upper Limb Surgery: A Double-Blind Randomized Controlled Trial

Abstract

Background: Ultrasound-guided axillary brachial plexus block is widely used for elective upper limb surgeries due to its effectiveness and safety. Two commonly employed techniques are the perineural and perivascular approaches. While the perivascular technique is technically simpler, the perineural approach may provide faster onset and superior block quality. This study compared the efficacy, safety, and hemodynamic effects of both techniques.

Methods: A double-blind randomized controlled trial was conducted among 160 patients undergoing elective upper limb surgeries, with 80 patients each allocated to the perineural (PN) and perivascular (PV) groups. Ultrasound-guided axillary brachial plexus block was performed using standardized anesthetic protocols. Primary outcomes included sensory and motor block onset times and block success rate. Secondary outcomes included duration of sensory and motor blockade, rescue analgesia requirement, supplemental block requirement, hemodynamic parameters, and complications. Statistical analysis was performed using appropriate comparative tests, with p < 0.05 considered significant.

Results: The perineural approach demonstrated significantly faster sensory and motor block onset, higher block success, and superior block quality compared with the perivascular approach. Sensory block duration (402 ± 76 vs. 362 ± 73 min; p = 0.001) and motor block duration (344 ± 68 vs. 319 ± 65 min; p = 0.020) were significantly longer in the PN group. Rescue analgesia (7.5% vs. 17.5%; p = 0.049) and supplemental nerve block requirements (10.0% vs. 22.5%; p = 0.035) were significantly lower in the PN group. Complications, including vascular puncture and paresthesia, were less frequent with the perineural technique, resulting in a lower overall complication rate (7.5% vs 22.5%; p = 0.009). Hemodynamic parameters remained comparable between groups.

Conclusion: The perineural approach is superior to the perivascular technique for ultrasound-guided axillary brachial plexus block, providing faster onset, improved block success, prolonged analgesia, reduced analgesic requirements, and fewer complications while maintaining hemodynamic stability. It should be considered the preferred technique for elective upper limb surgeries.