Thoracic Outlet Syndrome (TOS) is a condition that involves compression of nerves or blood vessels in the thoracic outlet, the space between the collarbone and the first rib. The condition can result in a range of symptoms, including pain, numbness, and weakness in the arm, neck, and shoulder areas. Diagnosing TOS, however, is often challenging due to the complexity of the condition and the overlap of its symptoms with other disorders. As a result, several diagnostic tests are typically conducted to confirm the presence of TOS and determine its severity.
If you’re scheduled for Thoracic Outlet Syndrome testing, you might feel anxious or uncertain about the process. Understanding what to expect during testing can help alleviate some of that anxiety and give you a clearer picture of the journey ahead. Below is an overview of the different tests and what happens during each one.
Initial Consultation and Physical Examination
Before any diagnostic testing begins, your healthcare provider will conduct a thorough assessment of your medical history and symptoms. The goal here is to establish whether TOS is a plausible diagnosis and to rule out other possible conditions. Expect the doctor to ask detailed questions about your pain, including:
Where and when did it start?
How severe is it?
What activities worsen or relieve the pain?
Do you have any history of trauma or injury to the neck, shoulder, or arm?
Once the doctor has a better understanding of your symptoms, they will perform a physical examination. This typically involves checking your posture, the range of motion in your shoulder and neck, and testing the strength and reflexes in your arms and hands. The doctor may also observe your arm and hand positioning to identify any unusual signs that might suggest nerve or vascular compression.
Physical tests play a crucial role in the diagnosis of TOS, and there are a few maneuvers your doctor may perform to assess how your body reacts under certain conditions. Some of these tests include:
Adson’s Test: The doctor will ask you to turn your head to one side and take a deep breath while the doctor feels for the pulse in your neck. If the pulse diminishes or you experience discomfort, it could indicate TOS.
Roos Test: In this test, you will be asked to raise both arms to shoulder level and repeatedly open and close your hands for a few minutes. This maneuver tests the function of the nerves and blood vessels as your arms are held in a particular position.
Wright’s Test: Also known as the hyperabduction test, this test involves raising your arms overhead and checking for signs of discomfort, pain, or pulse changes.
While these physical tests can be insightful, they are not definitive on their own. They may suggest the possibility of TOS, but further diagnostic testing is usually necessary to confirm the diagnosis.
Imaging Tests
Once the physical examination is complete, your doctor may recommend imaging tests to get a closer look at the anatomical structures in the thoracic outlet and rule out other potential causes of your symptoms, such as a herniated disc or bone abnormalities. Common imaging techniques used in TOS diagnosis include:
X-rays
X-rays are often the first imaging test recommended for suspected TOS. They help to rule out any structural problems, such as an extra rib (cervical rib), which could be compressing the nerves or blood vessels. Although X-rays can't directly diagnose TOS, they provide essential information regarding the anatomy of the thoracic outlet.
MRI (Magnetic Resonance Imaging)
MRI is a more advanced imaging technique that provides detailed images of soft tissues, including muscles, nerves, and blood vessels. An MRI can reveal whether there is any compression or abnormality of the brachial plexus, the network of nerves running from the spine to the arm thoracic outlet syndrome testing, or the subclavian artery, which can be compressed in TOS cases. This type of imaging is particularly useful for detecting soft tissue injuries or issues that may not be visible on X-rays.
CT (Computed Tomography) Scan
A CT scan is another diagnostic tool that may be used if more detail is needed. It is often combined with a contrast dye (CT angiography) to evaluate blood flow and the structures of the thoracic outlet more precisely. This method is particularly useful for detecting vascular TOS, where the blood vessels are compressed.
Ultrasound
Ultrasound imaging can help evaluate blood flow in the arteries and veins that pass through the thoracic outlet. It’s particularly useful for assessing venous TOS, where veins may become compressed, leading to swelling and other symptoms.
Nerve Conduction Studies and Electromyography (EMG)
In some cases, nerve conduction studies (NCS) and electromyography (EMG) are conducted to assess the function of the nerves affected by TOS. These tests are designed to measure how well the nerves are transmitting electrical signals, which can help determine whether the condition is affecting nerve function.
Nerve Conduction Studies (NCS): This test involves placing small electrodes on the skin over the affected nerves. A mild electrical impulse is sent through the nerves, and the doctor measures how quickly the nerve reacts. Slow or impaired nerve conduction may indicate nerve compression in the thoracic outlet.
Electromyography (EMG): This test measures the electrical activity in muscles. A needle electrode is inserted into the muscle to record electrical signals. If the muscle is receiving fewer signals than usual, it can indicate nerve damage or compression, which may be consistent with TOS.
While these tests can be uncomfortable, they are generally quick and provide valuable insights into nerve function. If the results of the NCS or EMG are abnormal, it could indicate that TOS is affecting the nerves that control your arm, hand, and shoulder muscles.
Vascular Studies
If your doctor suspects that TOS is affecting your blood vessels, they may recommend additional vascular studies. These tests help determine whether there is any compression of the arteries or veins that pass through the thoracic outlet. Some common vascular tests include:
Doppler Ultrasound: This test uses sound waves to create an image of blood flow in the vessels. It can detect any blockages or narrowing in the blood vessels that might be caused by TOS.
CT Angiography or MR Angiography: These advanced imaging techniques use a contrast dye to highlight blood vessels and identify areas where blood flow may be restricted.
Blood Tests
In rare cases, blood tests may be recommended to rule out other medical conditions that could be contributing to your symptoms. For example, autoimmune diseases or infections can cause similar symptoms to TOS. Blood tests help to identify any underlying conditions that could be complicating your diagnosis.
What Happens After Testing?
Once all the diagnostic tests are completed, your healthcare provider will analyze the results and make a diagnosis. If TOS is confirmed, the next step will be to determine the type of TOS—neurogenic (involving nerve compression), venous (involving veins), or arterial (involving arteries)—and develop an appropriate treatment plan. Depending on the severity of the condition, treatment options may include physical therapy, pain management, lifestyle changes, or, in more severe cases, surgery.
Conclusion
Undergoing testing for Thoracic Outlet Syndrome can be a multi-step process involving a combination of physical exams, imaging tests, nerve studies, and possibly vascular evaluations. Although the diagnostic process can seem overwhelming, it is a necessary step in identifying the cause of your symptoms and developing a treatment plan to improve your quality of life. Being prepared and understanding what to expect during testing can help ease the uncertainty and guide you toward the most effective treatment options for your condition.
