The subclavian perivascular block

Abstract

The subclavian perivascular technique, introduced by Winnie and Collins in 1964, is one of the most popular supraclavicular approaches to the brachial plexus. It is based on an anatomical concept, the existence of a fibrous tissue sheath surrounding the neurovascular bundle. This sheath acts as a barrier, limiting the diffusion of the local anesthetic away from the nerves. Thus, a single injection of an adequate volume of local anesthetic within this space is able to reach the components of the plexus, consistently producing good results. Different methods are employed to identify the presence of the needle inside the sheath. A fascial “click”, used by some, is a subjective sensation felt by the operator when the needle pierces the fascia. More popular is the technique of eliciting paresthesias. It requires physical contact between needle and nerve, as well as the patient's cooperation to qualify and locate the response. The possibility of increased risk of nerve damage has been raised with this technique. Lately, nerve stimulators have enjoyed increased popularity. They have the theoretical advantage of helping to bring the needle close enough to the nerve to ensure intrafascial injection, without the need for physical contact. The subclavian perivascular block, performed with a nerve stimulator, makes an already good technique even better.