Thoracic Outlet Syndrome

Abstract

The thoracic outlet syndrome [TOS] is most easily conceived as three conditions in which the elements of the neurovascular bundle, compressed at the thoracic outlet, produce a venous, an arterial and a neurogenic form of TOS. In the absence of hard diagnostic criteria and with the relative frequency of neurogenic TOS [NTOS], clinical skills remain important in the diagnosis and treatment of NTOS. The elevated arm stress test [EAST] is helpful as is the finding of brachial plexus tenderness behind the scalenus anterior muscle, and improved diagnostic accuracy can be gained from using a chemo denervation test with local anaesthetic or botox to identify and select patients with NTOS.

Arterial TOS [ATOS] and venous TOS [VTOS] are more easily diagnosed. Subclavian artery aneurysm, stenosis and occlusion may present in a non urgent way, and the ischaemia and any associated neurological symptoms are treated on their merits. The majority of ATOS presents acutely with embolism and is usually managed in a staged way with embolectomy, decompression and bypass.

VTOS most usually presents with subclavian artery vein thrombosis and needs to be distinguished from other secondary causes of axillosubclavian venous thrombosis. Thrombolysis and positional venography allows patients to be identified who are most likely to benefit from decompression, venolysis and venoplasty.