ABSTRACT
Thoracic outlet syndrome (TOS) is due to compression/irritation of brachial plexus elements ("neurogenic TOS") and/or subclavian vessels ("vascular TOS") in their passage from the cervical area toward the axilla. The usual site of entrapment is the interscalenic triangle. TOS is a highly controversial subject in regard to its incidence, diagnostic criteria and optimal treatment. Constitutional factors--osseous or more often fibromuscular--and external factors such as trauma predispose to the development of TOS. Various clinical pictures include pain in the cervical region and arm, paresthesias, aggravated by overhead positions of the arms, hand intrinsic muscle deficit/atrophy, easy fatiguability, paleness, coldness of hand. The clinical examination may be entirely normal or show cervical and scapular muscle spasm, tenderness of supraclavicular area, radial pulse attenuation upon positional maneuvers, sensory and/or motor deficit, usually of C8/T1 distribution. The diagnosis is based on clinical evaluation and absence of other relevant pathology. Sometimes TOS can enhance symptoms consecutive to cervical or supraclavicular lesions. Cervical spine and distal peripheral nerves are investigated by radiological and electrophysiological studies. Unless there is significant motor deficit or subclavian artery compression, the treatment should be kept conservative as long as possible, by adapted physical therapy. In case of neurological deficit or symptoms unresponsive to medical treatment, the patients will--like in other nerve entrapment syndromes--be helped by decompressive surgery, nowadays preferably performed via an anterior supraclavicular approach.
