Comparison of perineural brachial plexus block and proximal perivascular block in ultrasound-guided axillary brachial plexus block

The traditional axillary perineural (PN) approach for brachial plexus block is frequently used, but separate musculocutaneous nerve (MCN) block is required and increases procedure time and patient discomfort. We hypothesized that a block using the proximal perivascular (PPV) method at the MCN branching from the lateral cord would obviate the need for an MCN block while ensuring a quality similar to that of the PN method. For the PN group (n = 25), a needle was placed on each nerve, and 8 mL local anesthetic was infiltrated around the radial, ulnar, and median nerves (total: 24 mL). We then injected 6 mL local anesthetic around the MCN. In the PPV group (n = 25), we moved the probe proximally until the branching junction of the the MCN in the lateral cord. The needle tips were placed in the 12-o’clock and 6-o’clock positions of the axillary artery, and 15 mL local anesthetic was injected (total: 30 mL). The procedure time, number of needle passes, procedure-related complications, sensory/motor block level, and onset time were recorded. The PPV group had a significantly shorter procedure time than the PN group (3.9 ± 1.0 vs. 7.5 ± 3.3 min, p < 0.001). Furthermore, the PPV group required fewer needle passes. The PN group showed a significantly faster onset time than the PPV group (6.4 ± 2.7 vs. 10.4 ± 2.9 min, p < 0.001). The induction time did not show significant intergroup difference. Sensory blockade in the PN group occurred significantly faster than that in the PPV group at 5 and 10 min. There were no significant differences in motor nerve paralysis. PPV axillary block under ultrasound guidance was as effective as the PN axillary block. Therefore, the PPV axillary block is a simple, safe and effective regional technique for upper limb surgery.