What are the diagnostic criteria for Thoracic Outlet Syndrome (TOS)?

From the Guidelines

Diagnosing thoracic outlet syndrome (TOS) requires a comprehensive approach that includes clinical evaluation, physical examination, and diagnostic tests, with a focus on identifying the specific type of TOS (neurogenic, vascular, or nonspecific) to guide treatment and improve patient outcomes. The diagnostic process should begin with a thorough medical history, focusing on symptoms like pain, numbness, or weakness in the neck, shoulder, arm, or hand, especially with overhead activities 1. Physical examination should include provocative tests such as the Adson's test, the elevated arm stress test (EAST), and the costoclavicular maneuver, as well as a neurological examination to assess for sensory changes, muscle weakness, and reflex abnormalities.

Imaging studies are essential in the diagnosis of TOS, and the choice of imaging modality depends on the suspected type of TOS. For example:

• Chest X-rays can identify cervical ribs or other bony abnormalities 1
• MRI can evaluate soft tissue structures and is particularly useful in diagnosing venous TOS (vTOS), with noncontrast MRI findings including effacement of fat adjacent to the subclavian vein, and IV contrast providing optimal assessment of the subclavian vein and venous collaterals 1
• CT scans can provide detailed bone visualization and are preferred for evaluation of vascular TOS (vTOS) with IV contrast, allowing for assessment of vascular patency and potential complications in the postintervention setting 1
• Vascular studies like duplex ultrasound, arteriography, or venography may be necessary if vascular TOS is suspected
• Electrodiagnostic tests such as nerve conduction studies and electromyography can help identify neurogenic TOS

A comprehensive approach is important because TOS can be neurogenic (affecting nerves), vascular (affecting blood vessels), or nonspecific (disputed), with each type requiring different diagnostic approaches. Diagnosis is often challenging due to symptom overlap with other conditions, so ruling out alternative diagnoses like cervical disc disease or peripheral nerve entrapment is crucial 1.

Key points to consider in the diagnosis of TOS include:

• The need for a thorough medical history and physical examination to identify symptoms and signs of TOS
• The importance of imaging studies in diagnosing TOS, with the choice of modality depending on the suspected type of TOS
• The need to rule out alternative diagnoses and consider the potential for complications in the postintervention setting
• The importance of a comprehensive approach to diagnosis and treatment to improve patient outcomes and reduce morbidity and mortality.

From the Research

Diagnostic Approach

To diagnose thoracic outlet syndrome (TOS), a thorough clinical examination and appropriate clinical testing are essential 2, 3. The diagnosis of TOS is complex, and a careful history and physical examination are crucial in establishing the diagnosis 3.

Clinical Diagnostic Tests

Several clinical diagnostic tests can be used to diagnose TOS, including:

• Halstead maneuver (also known as the costoclavicular maneuver or exaggerated military brace test) 4
• Wright's test 4
• Cyriax Release test 4
• Supraclavicular pressure test 4
• Upper limb tension test 5
• Abducting the arms to 90 degrees in external rotation 5

These tests can help provoke symptoms in patients with TOS, but they do not allow for the differential diagnosis of TOS exclusively 4. The use of Adson's test and Roos test is not recommended for the differential diagnosis of TOS 4, 5.

Imaging and Electrophysiological Studies

Imaging studies such as Doppler ultrasonography, electrophysiological investigations, and helical computed tomography (CT) angiography can be useful in diagnosing TOS 6. These studies can help visualize vascular parietal abnormalities, confirm the diagnosis, and provide information on the location and mechanism of vascular compression.

Types of TOS

There are three types of TOS: arterial TOS, venous TOS, and neurogenic TOS 5. Each type has different symptoms and physical findings, and the diagnosis should be specific to the type of TOS. Neurogenic TOS is the most common type, comprising over 90% of all TOS patients 5.

Key Findings

• A thorough clinical examination and appropriate clinical testing are essential for diagnosing TOS 2, 3.
• Clinical diagnostic tests such as the Halstead maneuver, Wright's test, Cyriax Release test, and supraclavicular pressure test can be useful in diagnosing TOS 4.
• Imaging and electrophysiological studies can provide additional information and help confirm the diagnosis 6.
• The diagnosis of TOS should be specific to the type of TOS, and the treatment approach should be determined by the nature of the pathologic condition and site of compression 3, 5.