Thoracic Outlet Syndrome

What is Thoracic Outlet Syndrome?

The thoracic outlet refers to the space between the collar bone and the first rib. As you can see from the diagram, several nerves and blood vessels pass through this space before travelling down the arm. Thoracic Outlet Syndrome is a collection of symptoms caused by pressure or compression of these nerves and / or blood vessels in this space.

What are the symptoms of Thoracic Outlet Syndrome?

The symptoms of Thoracic Outlet Syndrome are very varied and differ from person-to-person and can include pain, pins and needles, numbness, burning sensations, electric shock sensations, weakness, fatigue, swelling, changes in the colour or temperature of the arm or hand. These symptoms can affect the neck, shoulder, arm, face, head, chest and thorax.

Are there different types of Thoracic Outlet Syndrome?

Three different types of Thoracic Outlet Syndrome are recognised. The most common type is called Neurogenic Thoracic Outlet Syndrome (nTOS) and this is caused by compression of or pressure on the nerves in the thoracic outlet. It is thought to make up about 90% of all cases of Thoracic Outlet Syndrome. The main symptoms of nTOS are pain, tingling and numbness travelling down the arm and into the hand. However the symptoms can also affect the head, face, neck and trunk. Some patients report weakness in the arm or the hand.

The second most common type of Thoracic Outlet Syndrome is called Venous Thoracic Outlet Syndrome (vTOS). This has been reported to make up about 10% of cases and occurs when there is compression of the vein in the thoracic outlet. The common symptoms of vTOS are pain and swelling of the arm and visible enlargement of the veins of the arm or across the chest.

The rarest type of Thoracic Outlet Syndrome is Arterial Thoracic Outlet Syndrome (aTOS) and is caused by pressure on the artery in the thoracic outlet. It is thought to make up just 1% of all cases. This can cause pain and weakness in the arm or hand and changes in the colour of the skin of the hand or arm often made worse by exertion.

Some people may have more than one of these different types of Thoracic Outlet Syndrome.

What causes the compression of the nerves or blood vessels in the thoracic outlet?

There are several reasons why people can develop pressure on the vessels in the thoracic outlet. Overall, anything that reduces the volume of this space can lead to the condition. Some people have congenital variations in the anatomy of their bones (for example an extra rib) that can reduce the size of the space. Other people develop tightness or tension in the muscles at the side of the neck (scalenei) or at the chest pectoralis minor). A wide variety of factors can contribute to the onset of symptoms but a common report from our patients is that the symptoms came on after a period of intensive activity such as lifting or carrying, carrying a heavy ruck sack, playing musical instruments, computer work or a wide variety of other upper limb activities.

How is Thoracic Outlet Syndrome diagnosed?

Unfortunately, Thoracic Outlet Syndrome is not well recognised by many healthcare professionals and one study showed on average it takes 7 years for a patient to receive a firm diagnosis. This means that many patients circulate around the healthcare system collecting a variety of different “diagnoses” and erroneous explanations for their symptoms. In fact sometimes patients are told that their symptoms are psychological or due to a functional neurological syndrome or simply not believed. This happens because many doctors and other healthcare professionals do not understand the condition. In particular they are perplexed by the array of severe symptoms that the patient reports but a series of MRI scans and nerve conduction studies that show no abnormalities. So why do these investigations often show no abnormalities?

One of the reasons for this is that Thoracic Outlet Syndrome is usually only provoked by raising the arm above the level of the shoulder as this naturally closes down the space in the thoracic outlet. It is in this position that the nerves and / or blood vessels are compressed. However most MRI scans, ultrasound scans and nerve conduction studies are done with the patient’s arm by their side.

At Evidence-Based Therapy Centre, specialist shoulder physiotherapist, Eoin Ó Conaire has a special interest in Thoracic Outlet Syndrome. He believes that to diagnose Thoracic Outlet Syndrome, firstly it is important to take very careful and thorough history of the problem. He also believes that it is vital that the person doing the assessment has expertise in diagnosing neck, shoulder and nerve related problems as well as experience and expertise in Thoracic Outlet Syndrome. Secondly a detailed physical examination must include tests to include or exclude neck, shoulder, other peripheral nerve problems, a detailed neurological examination and also specific clinical tests for Thoracic Outlet Syndrome. Sometimes the diagnosis is very clear from the clinical examination but on other occasions, it is important for Eoin to refer for other investigations to help rule-in or rule out the variety of conditions that can cause the symptoms. Eoin will explain in detail his findings with you and discuss the rationale for any further investigations.

The criteria for diagnosis of Thoracic Outlet Syndrome has been quite controversial over the years. However in 2016, the American Society for Vascular Surgery published guidelines for the gold standard tests and reporting for Thoracic Outlet Syndrome. You can read the paper here.

What are the effective treatments for Thoracic Outlet Syndrome?

Once the diagnosis has been established, broadly speaking there are two treatment options: physiotherapy or surgery. Eoin will discuss these options with you and based on the findings in the assessment will recommend either a trial of physiotherapy or a referral for surgical evaluation. At Evidence-Based Therapy centre, the physiotherapy regime for Thoracic Outlet Syndrome can include education about the condition, exercises, manual therapy, modification of posture or shoulder girdle position, ergonomic changes and graduated functional rehabilitation to return you to the activities that have been causing the symptoms. Sometimes physiotherapy will be supplemented by medications to help with nerve pain or injections such as muscle block injections or Botox injections. Eoin also oversees rehabilitation after patients undergo surgery.

Appointments

If you think that you may have Thoracic Outlet Syndrome and would like to book an appointment for assessment with Eoin, you can call Evidence-Based Therapy Centre on 091 727777 or email admin@ebtc.ie. Please note that for a full Thoracic Outlet Syndrome assessment, you will need to book a 90 min appointment.