Types of Thoracic Outlet Syndrome (TOS)
Neurogenic TOS (nTOS)
Most common form of TOS. Inability to complete elevated arm stress test (EAST) is highly suggestive of nTOS. Multiple other adjunctive testes may be helpful but no specific test is diagnostic.
Venous TOS (vTOS)
Venous TOS is usually obvious in a young patient presenting with effort thrombosis of the axillosubclavian veins. Venous duplex is helpful in diagnosis but may miss subclavian vein thrombosis. CTV, MRV, and formal venogram are all acceptable initial tests. The formal venogram has the advantage of performing dynamic arm abduction and rotation to visualize compression and to perform thrombolysis. Once lysis is complete and compression identified, it is typical to wait 6 weeks to perform first rib resection, although immediate resection is gaining popularity.
Arterial TOS (aTOS)
Least common, with prevalence estimated in single digits. Bony abnormality is usually present and is associated with arterial injury such as subclavian artery aneurysm. Upper extremity Doppler study with arm elevation is positive in up to 60% of normal subjects, and is not helpful in diagnosis.
Diagnosis
Chest X-ray
Chest x-ray is essential for ruling out bony abnormalities such as cervical rib or other bony abnormalities that may cause TOS
WBI/Duplex
Noninvasive vascular tests are somewhat unhelpful. About 20% of asymptomatic individuals will exhibit arterial compression with abduction maneuvers.
CTA
CTA is the most helpful and is the diagnostic test of choice in aTOS.
Types of Thoracic Outlet Exposures
Supraclavicular
Good visualization of subclavian artery and brachial plexus, appropriate for subclavian artery exposure and neurolysis. This exposure also allows you to expose the posterior aspect of first rib for complete resection. Can combine with infraclavicular exposure to resect the most anterior portion of the first rib at the sternum. The combination of supraclavicular and infraclavicular exposures are also useful in arterial TOS where proximal and distal controls are necessary to reconstruct the subclavian artery.
Infraclavicular
Good exposure of subclavian vein. Unable to expose posterior aspect of first rib. Appropriate for venous thoracic outlet syndrome as rib resection only needs to clear the venous obstruction.
Transaxillary
The biggest advantage of the transaxillary approach is that it exposes the entire rib, but cannot see the brachial plexus. It is also not good for vessel reconstruction.