Selective ulnar nerve localization is not essential for axillary brachial plexus block using a multiple nerve stimulation technique

Abstract

Background and objectives: The multiple-injection technique for axillary block, in which the 4 distal nerves of the plexus are located by a nerve stimulator and separately injected, has been shown to produce a rapid onset and a high success rate. However, this technique may be more difficult and time consuming than other axillary block methods. A simplified multiple-nerve stimulation technique, in which the ulnar nerve was not located, was compared in the present double-blind study to the 4-injection approach.

Methods: Eighty-four patients were randomly allocated to 2 groups. In group IV, all 4 distal nerves of the plexus were located by a nerve stimulator and injections made. In group III, all the nerves but the ulnar were located and injections made. The block was defined as complete when analgesia was present in all the sensory areas distal to the elbow.

Results: The time to perform the block was shorter in group III (5 +/- 2 v 8 +/- 3 minutes; P <.001). Block performance pain was lower in group III patients (8 +/- 2 v 13 +/- 2 mm; P <.001). The onset time (15 +/- 6 v 16 +/- 7 minutes) and the frequency (90% v 92%) of complete block were not different between the groups.

Conclusions: A triple-injection method of axillary block in which the ulnar nerve was not purposely located provides a spread and a latency of sensory block equal to that obtained with a 4-injection technique. A shorter performance time is an advantage of this approach.