How do you test for thoracic outlet syndrome (TOS)?

From the Guidelines

Thoracic outlet syndrome (TOS) is best tested through a combination of physical examination maneuvers and diagnostic imaging, with the initial evaluation typically including provocative tests such as the Adson's test, the elevated arm stress test (EAST or Roos test), and the costoclavicular maneuver, as well as diagnostic imaging like MRI or CT scans to visualize soft tissue compression, as recommended by the American College of Radiology Appropriateness Criteria 1. The diagnostic approach to TOS should prioritize the patient's specific symptoms and the suspected type of TOS (neurogenic, vascular, or a combination of both), with a thorough history focusing on symptoms, their triggers, and exacerbating factors being essential for guiding the diagnostic process. Some key points to consider in the diagnostic evaluation of TOS include:

• The use of provocative tests to reproduce the patient's symptoms, such as the Adson's test, the EAST or Roos test, and the costoclavicular maneuver.
• The importance of diagnostic imaging, including MRI or CT scans, to visualize soft tissue compression and assess vascular patency.
• The need to consider the patient's specific symptoms and the suspected type of TOS when selecting diagnostic tests and interpreting results.
• The value of a thorough history and physical examination in guiding the diagnostic process and determining the most appropriate diagnostic tests. The American College of Radiology Appropriateness Criteria provide evidence-based guidelines for the diagnostic evaluation of TOS, including recommendations for the use of MRI, CT scans, and other diagnostic tests 1. In terms of specific diagnostic tests, the following may be considered:
• MRI without IV contrast for the evaluation of neurogenic TOS, as it can provide detailed images of the brachial plexus and surrounding soft tissues 1.
• CT with IV contrast for the evaluation of vascular TOS, as it can provide detailed images of the subclavian artery and vein and assess vascular patency 1.
• US duplex Doppler for the evaluation of vascular TOS, as it can provide detailed images of blood flow and assess vascular patency 1. Ultimately, the diagnostic evaluation of TOS should be tailored to the individual patient's needs and symptoms, with a focus on determining the underlying cause of their symptoms and guiding effective treatment.

From the Research

Testing for Thoracic Outlet Syndrome

To test for thoracic outlet syndrome (TOS), several methods can be employed, including physical examinations, imaging tests, and provocative maneuvers. The diagnosis of TOS is often based on a combination of these methods.

• Physical Examination: A thorough physical examination is crucial in diagnosing TOS. This includes assessing the patient's symptoms, medical history, and performing provocative tests such as neck rotation, head tilting, and arm abduction to elicit symptoms 2.
• Imaging Tests: Imaging tests like MRI, CT scans, and angiography can help identify anatomical abnormalities, such as cervical ribs, and vascular compression or thrombosis 3, 4, 5.
• Provocative Maneuvers: Provocative maneuvers, including the upper limb tension test and abduction of the arms to 90 degrees in external rotation, can help reproduce symptoms and confirm the diagnosis 2, 6.
• Nerve Conduction Studies: Nerve conduction studies and electromyography may be used to rule out other conditions, but they are often normal in patients with TOS 4.
• Angio-MRI: Gadolinium-enhanced angio-MRI can be useful in evaluating TOS, particularly in demonstrating vascular compression and thrombosis 3.
• MRI Findings: MRI findings in TOS may include compression of the neurovascular bundle, congenital bone variations, and congenital fibromuscular anomalies 5.

Types of Thoracic Outlet Syndrome

There are three main types of TOS: neurogenic, venous, and arterial. Each type has distinct symptoms and physical findings.

• Neurogenic TOS: The most common type, accounting for over 90% of TOS cases, caused by brachial plexus compression, often due to scarred scalene muscles secondary to neck trauma 2.
• Venous TOS: Presents with arm swelling, cyanosis, and pain due to subclavian vein obstruction, with or without thrombosis 2, 3.
• Arterial TOS: The least common type, caused by emboli arising from subclavian artery stenosis or aneurysms, presenting with symptoms of arterial ischemia 2.