Diagnosing Thoracic Outlet Syndrome can be difficult as signs and symptoms are often confused with other conditions and symptoms can be vague. This is especially true with predominant Neurogenic Thoracic Outlet Syndrome as pain and tingling are often the only complaints. The diagnosis of Thoracic Outlet Syndrome is of much debate and disagreement among healthcare providers. To date, there is no agreed upon, nationally researched diagnostic tool or procedure used to diagnosis neurogenic TOS.
The most important aspect of diagnosing the cause of your symptoms is for your healthcare provider to rule out anything life or limb threatening. He or she may also look for a differential diagnosis to explain your symptoms. Thoracic Outlet Syndrome can occur independently or in conjunction with other medical conditions of the upper extremity, chest and neck. If you suspect any life or limb threatening problems you should go to the emergency room immediately.
Many times patients are told they have TOS based on losing their pulse with arm elevation. This test does NOT completely rule in or out Thoracic Outlet Syndrome and has been shown to be "positive" in people without symptoms or TOS. Some TOS experienced physicians continue to use this arm test but only has a small part of the clinical exam or not at all. These arm tests are usually followed by more advanced diagnostic testing such as scalene blocks, chest x-ray, cervical spine x-ray, Cat Scan (CT), MRI/MRA and electrophysiology studies.
One of the most important first steps in diagnosing Thoracic Outlet Syndrome is giving a comprehensive history of your symptoms to your TOS experienced physician. Some patients keep a list of their symptoms and bring it to their first exam. Each physician has his own method of history taking but you can be assured these questions may be included. Expect your TOS examination to last for some time. Some patients report that their TOS physician spent over an hour for their exam, so be prepared for this. Most TOS experienced physicians rely heavily on a long standing hands-on clinical examination and each physician has hisown way in proceeding with the exam. Additionally, each TOS physician has their own opinion about many of the TOS diagnostic procedures currently available today. If your physician suspects that you may have vascular involvement, he or she may order additional invasive and non invasive diagnostic tests such as ultrasound, CT, MRI, venogram and arteriogram. You should discuss the risk and benefits of each procedure with your physician.
Electromyography (EMG)
Your physician may order an EMG test. This is a nerve conduction study commonly performed to help rule out other compression neuropathies of the upper extremity. The reliability of EMG studies is of debate in diagnosing TOS as often times these studies are inconclusive. Currently, the Medial Antebrachial Cutaneous (MAC) nerve conduction test is being studied by some clinicians as an alternative or addition to EMG studies in diagnosis of TOS but has not been proven nationally. Many patients report that although EMG studies are tolerable, there is some intermittent pain involved. Be sure you discuss this with your physician. The State of Washington has recently released their version of EMG guidelines.
Arm Elevation Tests
Arm elevation tests for diagnosing TOS have been the subject of much controversy and still are today. The Adson's Maneuver is thought to have false positive rates among the general population and is not a sole predictor of TOS. The Adson's test is still used in practice today but is generally given little weight without more advanced diagnostic testing. Arm tests such as the EAST test are now thought to be more reliable but need further research. These tests can be correlated with TOS but further diagnostic work up is almost always necessary, especially if your physician suspects vascular involvement
Scalene Blocks/Injections
Scalene injections using a numbing agent or Botox are currently being used and studied by some physicians, as a predictor of treatment outcome, to determine if the Scalene muscles are causing compression with the Thoracic Outlet and to reduce pain. These procedures may be done with the patient sedated and are usually done with the help of a visual aide such as ultrasound, CT or fluoroscopy. Some physicians place a predictive value on scalene injections but this is not agreed upon or nationally proven. Some patients have reported a total relief of pain temporarily while others report no or minimal short acting pain relief. There have been patient reports of increased pain (increased pain flair) post injection by some of our members. In any event, scalene injections are now being evaluated in diagnosing and treating Thoracic Outlet Syndrome. As with any medical procedure, there are risks with this procedure, especially if the injections are unguided. It is important for you discuss these risks with your physician.
Computed Tomography (CT)
CT is done to assess the structures within the thoracic outlet. Some times a CT is ordered "with contrast". This means that dye will be injected into your veins through an IV (intravenous line) to determine the condition of your blood vessels and to determine if you have a DVT (blood clot) or aneurysm. There are risks with this procedure and you should discuss these risks with your physician and also the CT staff.
Magnetic Resonance Imaging (MRI)
An MRI studying vessels can also be ordered "with contrast". Contrast MRI imaging, Magnetic Resonance Angiogram (MRA), helps enhance the visualization of structures within the thoracic outlet. MRI and MRA’s have advantages over CT in that radiation exposure is avoided and the pictures are more detailed but as with any medical procedure there are risks. Discuss the risk and benefits with your physician and MRI staff.
Ultrasounds(US)
US is generally painless. Your physician may order an ultrasound of your brachial plexus and/or blood vessels to determine compression within the thoracic outlet and to also determine the presence of blood clots, narrowing of a vessel and aneurysms. Discuss the risk and benefits with your physician and ultrasound staff.
It is not uncommon for patients to seek several opinions from TOS experienced physicians. Many patients travel outside of their home state for diagnosis and treatment.
Types of TOS Symptoms Diagnosing TOS Treatment Patient Resources Find a Provider
This information was reviewed and edited by Dr. Wladislaw Ellis, M.D. TOS Specialist
