Thoracic outlet syndrome

Thoracic Outlet Syndrome Thoracic outlet syndrome is a term designating a spectrum of upper extremity neurovascular symptoms and signs referable to compression of the brachial plexus or the vessels exiting the thoracic outlet, or both. The structure that is compressed and the obstructing lesions are variable.

Compression of the lower brachial plexus by the first rib is the most common cause of thoracic outlet syndrome. Other causes of compression include a cervical rib, the anterior scalene muscle and fibrous bands. The syndrome usually presents idiopathically, but cervical trauma, hypertrophy of the shoulder muscles and advanced age may be predisposing factors in some patients. The importance of the first rib as the common denominator in all forms of thoracic outlet syndrome has been noted.

Symptoms vary greatly, depending on whether a nerve, artery or vein is being compressed. When nerves are compressed, the patient experiences pain, paresthesias, motor weakness and Raynaud's phenomenon. Compression of an artery results in ischemia, coldness, necrosis and claudication, while compression of a vein causes edema, cyanosis and thrombosis. Symptoms may overlap if more than one structure is involved in compression.

Sellke and Kelly note that thoracic outlet syndrome can be severely disabling, but can be managed with an orderly approach to diagnosis, followed by physical therapy or surgery, or both. The diagnosis is based on a thorough history and physical examination that excludes other causes of arm and shoulder pain. Angiography and electromyography are of limited value and should be performed only in selected cases.

Conservative management involves extensive physical therapy, including exercise of the shoulder girdle and traction with a cervical halter. If these methods are unavailing, operation may be required. Surgery consists of transaxillary resection of the first rib, with removal of fibromuscular bands and cervical ribs, when present. The authors report on their series of 473 patients who underwent surgery for thoracic outlet syndrome. Relief of symptoms was obtained in over 90 percent of the patients, with 79 percent having complete resolution of symptoms and 14 percent having partial relief. (American Journal of Surgery, July 1988, vol. 156, p. 54.)

COPYRIGHT 1989 American Academy of Family Physicians
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