What is TOS?
The arm vein, artery and nerves all pass between the collar bone and the bone of the first rib. When one or more of these gets compressed between these bones, people can get vein or artery blockage or nerve numbness, weakness or pain. Thoracic Outlet Syndrome (TOS) tends to affect young active adults. Diagnosis and treatment are important in order to reduce the chances of lifelong problems.
There are three types of TOS – arterial, venous and neurogenic. The artery type is less common compared to the vein and nerve types.
Venous TOS (VTOS)
Venous TOS is mostly seen in young adults who do a lot of repetitive overhead arm movements. These may be labourers, gym-goers who do weight training or swimmers. It will usually affect the dominant arm. In some people there may be an underlying blood clotting problem but this is not usually the case.
Another term for VTOS is Paget-Schroetter syndrome.
The features of VTOS are similar to those of a deep vein thrombosis (DVT) in the legs. Sudden onset of arm swelling, with blush discolouration is common.
Arterial TOS (ATOS)
Arterial TOS is mostly caused by extra neck ribs or extra fibrous tissue in this area that compresses the artery. Over time, the artery may block off or sometimes grow bigger and form an aneurysm.
Extra neck ribs are also called cervical ribs. About 1% of the population has these. They are more common in women.
ATOS relates to artery blockage, or to artery expansion, and is also called aneurysm. Artery blockage can cause either sudden or gradual poor blood flow to the fingers, hand and muscles of the arm. Aneurysm can cause a noticeable pulsating lump above the collar bone.
Neurogenic TOS
Neurogenic TOS is by far the most common type. It typically affects adults in their 30s and 40s. Extra neck ribs and fibrous tissue can be a cause but neck trauma from falls and vehicle accidents would be the most common underlying cause.
The features of NTOS relate to nerve problems affecting the arm, causing numbness, tingling, weakness and pain.
How is Thoracic Outlet Syndrome diagnosed?
Diagnosis is usually based on a patient’s arm symptoms, along with a number of tests. Often many of these are used in combination to get a clear diagnosis.
X-rays can look for extra neck ribs or any other bone problems.
Ultrasound scan can look at the veins and arteries in different positions to see whether there is compression. This is not completely diagnostic because about 25% of normal people get compression when the arm is placed in certain positions but ultrasound can easily detect blockages and aneurysms.
CT and MRI scans can give information on the vessels, nerves and spinal cord, muscles, bones and joints. Nerve impulse tests can work out where a nerve is being compressed.
What are the treatments for Thoracic Outlet Syndrome?
In some people, if a vein or artery blocks off causing only minor symptoms, no further treatment will be needed. This is also the case with minor nerve symptoms. Avoiding the repetitive actions that initially caused the problem is advisable. For vein blockages, blood thinners may be necessary for a period of time.
When treatment is necessary, the general aim is to treat the specific vein, artery or nerve problems and then to create more space for these structures as they pass between the collar bone on the first rib. Usually, a combination of X-ray techniques, such as stents and surgery can clear blood vessel blockages. Surgery can fix blocked arteries, aneurysms and clear fibrous and scar tissue from around the nerves. Also, removing the first rib, and any extra neck ribs, can create extra space and remove the compression on the vein, artery or nerves.
And the results of treatment?
Treatment results for vein and artery problems are predictably good. Many patients will have significant improvement.
Results for those with nerve problems are much less predictable, because some patients in this group may have had the problem for many years. Many will have chronic pain syndromes. So a multidisciplinary team of vascular surgeon, neurologist, pain specialist, physiotherapist and psychologist offers the best chance of a good result. Consequently, about 10% of NTOS patients will need surgery to free up compressed nerves and open up the space between the collar bone and first rib.
