Thoracic outlet syndrome or TOS

What is it about ?

Thoracic outlet syndrome (TOS) is a term for symptoms that appear when the nerves and blood vessels that go to the arm are compressed in their path. At shoulder height, this nerve and vascular bundle exits the rib cage (thorax) and neck. This area is called the thoracic outlet (“thoracic outlet”). In some people, this “crossing” may be narrowed and this compresses the nerve and vascular bundle when the arm is in certain positions.

At whom and how often do we meet it?

This syndrome occurs more frequently in women than in men and is rare after the age of 50.

How to recognize it?

Characteristic symptoms are pain and numbness in the fingers, hands, forearms and shoulders. The pain can radiate to the chest. Symptoms also occur during activities with the arms raised, at shoulder height or higher. Nocturnal symptoms may appear after exercise.

How is the diagnosis made?

The doctor will do some tests first. Their purpose is to trigger symptoms by narrowing the “crossing”. If one or more of these tests trigger symptoms, it suggests TOS. The tests are carried out with care. Other signs such as limited mobility of the upper part of the spine or an abnormal pulsation of the brachial artery (palpated or listened to with a stethoscope) are also checked.

In addition, the doctor will request some technical examinations to rule out other causes:

• An x-ray of the chest and top of the spine (cervical vertebrae) to rule out a tumor, neck problem, or the presence of an extra rib.
• An MRI (magnetic resonance imaging, also called an NMR) to check if it is a herniated disc or for neurological conditions such as a multiple sclerosis (MS).
• A nerve conduction test (electromyography) to differentiate it from other causes of pressure on the nerves in the arm, such as carpal tunnel syndrome. In this case, it is at the level of the wrist that the nerve is compressed.

What can you do ?

Complaints are often due to static work, at height (at shoulder level or even higher). That is why you should avoid these kinds of tasks as much as possible.

What can your doctor do?

The basis of treatment is physiotherapy. This technique strengthens the right muscle groups and allows you to correct your posture. It is important to stick to this treatment for a long time. Only like this will you be able to achieve good results. An intervention in which an attempt is made to eliminate the cause of the pinching is reserved for severe cases.

Source

Foreign clinical practice guide ‘Thoracic outlet syndrome’ (2000), updated on 09/21/2016 and adapted to the Belgian context on 03/06/2018 – ebpracticenet