Thoracic outlet syndrome (TOS) is described as group of symptoms resulting from compression of the neurovascular structures supplying the upper extremity as they exit through the thoracic outlet [1]. The three forms of TOS are arterial TOS (aTOS), venous TOS (vTOS), and neurogenic TOS (nTOS), with the latter being by far the most common variant. The variations in the type of TOS have distinct clinical features, but all of them can be associated with repetitive upper extremity activities and space occupying structures within the interscalene triangle [2].

Arterial TOS involves intermittent compression of the subclavian artery as it exits the thoracic outlet. The compression results in intimal injury and arterial stenosis through which there is turbulent blood flow. Often, there is post-stenotic dilation or even aneurysm formation and intimal ulceration that results in thrombus formation with risk of embolization. Patients may feel effort-induced arm claudication because of the subclavian artery stenosis or may present with acute limb ischemia from a thromboembolic event. Venous TOS involves compression the subclavian vein [3]. Subsequent venous hypertension, inflammation and fibrosis lead to further narrowing of the vein and increase susceptibility to deep venous thrombosis [4]. Lastly, neurogenic TOS is a result of compression and stretching of the brachial plexus which can cause pain, paresthesia, poikilothermia and weakness of the affected extremity and ipsilateral neck.

Over time, multiple different surgical specialties have been involved in the care of patients with all varieties of TOS, which may lead to challenges among community physicians recognizing the condition and not knowing which specialist has the expertise to provide appropriate treatment. Further confounding timely referrals and an accurate diagnosis, in the earlier stages of the disease process there can be significant overlap in symptomatology between the three TOS variants. Even in later stages, given the non-specific symptoms of neurogenic, as opposed to the vasculogenic varieties, nTOS can be difficult to diagnose. Delays in diagnosis may result in additional pain, debility and morbidity.