Thoracic outlet syndrome: An update

Abstract

Thoracic outlet syndrome (TOS) encompasses a group of symptoms believed to be a result of compression of the neurovascular structures traversing the thoracic outlet. The past two decades have seen a rapid increase in the diagnosis of neurogenic TOS, and the classic syndrome has evolved from one of vascular compression by bony structures to one of predominantly neurological entrapment by soft tissue anomalies. Electrophysiological tests are generally not useful in providing an objective evaluation and diagnosis. Advances in morphological and histopathological concepts suggest that anatomical and developmental variations and postural imbalance lead to a mechanical susceptibility of the brachial nerve roots to compression by surrounding muscular and soft tissue elements. Symptoms may be precipitated by cervical trauma inducing additional fibrosis. Bony abnormalities are rare. The traditional surgical treatment of empirical transaxillary first rib resection has gradually been replaced by the concept of precise identification of the pathology, through better exposure using the supraclavicular route. Anterior and middle scalenectomy with a neurolysis of the brachial plexus has been shown to be effective and incurs less morbidity than first rib resection. This procedure should be adopted as the initial operation for neurogenic TOS.