Diagnosis and Treatment of Thoracic Outlet Syndrome

Thoracic outlet syndrome (TOS) is one of the most controversial subjects in entrapment neuropathies. Views differ regarding the pathogenesis, diagnosis, and management of TOS. Some authorities even question its existence. In spite of lack of understanding of the disease, clinicians often encounter patients whose pain or neurologic deficits in the upper limb cannot be explained after ruling out cervical spine diseases and other common causes of peripheral neuropathies. The goals of this article arc to provide a comprehensive understanding of the syndrome by reviewing the anatomy of the region and the pathomecl~anism of the disease. Diagnosis can be established confidently in cases where the neurologic deficits are obvious and tests sho~tpositive findings. Issues surrounding cases TI-here the objective findings are minimal are discussed. The duration of conservative treatment, indications for surgery, surgical approach, and patient selection for surgery are not standardized, and experiences vary across institutions. A number of studies in the past have shown conflicting results on the outcome of various surgical approaches, which has only added to the confusion. A systematic scientific approach aimed at understanding the pathogenesis of TOS, elucidating the criteria for diagnosis, and defining the treatment protocol has never been undertaken. Future endeavors should include multicentric, randomized, prospective clinical trials so as to ansrver these questions. Until the first half of the nineteenth century, several terms were assigned to describe the symptom complex caused by neurovascular compression in the upper thoracic region based on the physiologic mechanism and structure that caused the compression (Table 1). Such rigid classification was the basis for explaining the pathogenesis, diagnosis, and treatment.22 4"5 80 In 1956, Peet et al-' coined a common term, thomcic outlet s y f d r . o : w , to encompass these various entities. It is now realized that strict classification is not practical. Patients tend to have multiple abnormalities, which may be responsible for the compression of the neurovascular bundle, and the clinical presentation is not unique to one ~yndrome.~"