From the Guidelines
To rule out thoracic outlet syndrome (TOS), a comprehensive clinical evaluation combined with specific diagnostic tests, including imaging studies such as chest X-rays, MRI or CT scans, and vascular studies, is necessary. The diagnosis of TOS is often one of exclusion, requiring careful elimination of other conditions that can mimic its symptoms, such as cervical disc disease, peripheral nerve entrapment, or shoulder pathology 1.
Key Diagnostic Steps
- Begin with a detailed medical history and physical examination, focusing on provocative maneuvers such as the Adson test, Wright test, and elevated arm stress test, which can reproduce symptoms by compressing the neurovascular structures.
- Imaging studies are essential, including:
- Chest X-rays to identify cervical ribs or other bony abnormalities.
- MRI or CT scans to visualize soft tissue structures.
- Vascular studies like duplex ultrasound, arteriography, or venography to assess blood flow.
- Nerve conduction studies and electromyography can help differentiate neurogenic TOS from other nerve compression syndromes.
- A scalene muscle block with local anesthetic may be performed as both a diagnostic and therapeutic measure; relief of symptoms suggests TOS.
Importance of Imaging
Imaging studies, particularly MRI and CT scans, play a crucial role in diagnosing TOS by visualizing the compression of neurovascular structures in the thoracic outlet 1.
Multidisciplinary Approach
In some cases, a multidisciplinary approach involving neurologists, vascular surgeons, and physical therapists may be necessary for accurate diagnosis and management of TOS 1.
Recent Guidelines
Recent guidelines, such as those from the American College of Radiology, emphasize the importance of a comprehensive diagnostic approach, including clinical evaluation and imaging studies, to rule out TOS 1.
From the Research
Ruling Out Thoracic Outlet Syndrome
To rule out thoracic outlet syndrome, the following steps can be taken:
- A careful and detailed medical history and physical examination are the most important diagnostic tools for proper identification of TOS 2, 3, 4
- Electromyography, nerve conduction studies, and imaging of the cervical spine and the chest can provide helpful information regarding diagnosis 2
- Specific clinical tests, whose accuracy has been documented, can be used to support a clinical diagnosis, especially when a cluster of positive tests are witnessed 3
- Provocative positional maneuvers can be evaluated for their vascular and neurologic response, but they do not "make" the diagnosis, and can be a useful adjunct for confirming the diagnosis 4
Diagnostic Considerations
When diagnosing TOS, it is essential to consider the following:
- TOS represents a spectrum of disorders encompassing three related syndromes: compression of the brachial plexus (neurogenic TOS), compression of the subclavian artery or vein (vascular TOS), and the nonspecific or disputed type of TOS 2
- Neurovascular compression may be observed most commonly in the interscalene triangle, but it also has been described in the costoclavicular space and in the subcoracoid space 2
- Symptoms of TOS include pain, paresthesia, pallor, and weakness depending upon the compromised structures 5
Differential Diagnosis
When ruling out TOS, it is crucial to consider other conditions that may present with similar symptoms, such as: