Thoracic Outlet Syndrome

Thoracic Outlet Syndrome

Thoracic Outlet Syndrome (TOS) is currently one of the most controversial syndromes in medicine in terms of definition, anatomy, aetiology and treatment. Although the symptomatology of TOS was described over 150 years ago, it was only in 1956 that the term ‘Thoracic Outlet Syndrome’ was suggested in an attempt to include a number of entities with similar symptoms.

HISTORY

Dr Laura Redman worked with Professor John Robbs who is a well-known vascular surgeon with an interest in Thoracic Outlet Syndrome. (See below)

Dr Redman wrote her Masters of Medicine (MMED) on the subject of the thoracic outlet syndrome and Prof Robbs was her supervisor. Together they worked on many cases.

Dr David Harris is a cardiothoracic surgeon at Kuilsrivier Hospital. He also has an interest in thoracic outlet syndrome and has been performing this surgery for many years. Since the end of 2014 Dr Redman and Dr Harris have worked together on patients with thoracic outlet syndrome, building up a practice together and looking at ways to reduce surgical morbidity. They selectively remove the first rib and not routinely (see below).

Professor Robbs was the previous Head of General and Vascular Surgery at the University of Natal. He currently runs a busy private practice at Hillcrest Private Hospital and he has interest in thoracic outlet syndrome.

Dr David Harris is a cardiothoracic surgeon at Kuilsrivier Private Hospital. He does part time work and teaching at Tygerberg hospital. He is an expert in minimally invasive cardiac surgery and has in interest in Thoracic Outlet Syndrome. He has built up a large practice of these patients as well.

WHAT IS THORACIC OUTLET SYNDROME?

The definition of TOS is generally accepted as: “Upper extremity symptoms due to compression of the neurovascular bundle in the area of the neck just above the first rib”.

Neurogenic TOS, resulting from nerve compression, is the commonest pathology accounting for over 95% of TOS cases. This is followed by venous compression identified in 2-3% of cases and lastly arterial entrapment making up only 1% of TOS symptoms.

The majority of cases result from anatomical distortion at the interscalene triangle.

As can be seen from the picture above, this space in the neck contains many structures including arteries, veins, nerves and lymphatics. The scalene triangle is made up of the anterior and middle scalene muscles along with the first rib forming the floor. All the nerves  (brachial plexus) travelling from the spinal cord to the arm travel through this triangular space.  If there is any compression of the space, one may experience symptoms in the neck, arm or hand.

There is another area that can also cause compression of the brachial plexus. This is under the pectoralis minor muscle. See the picture below. Often patients have nerve compression with tenderness at the point of the pectoralis minor muscle on the chest.

WHAT ARE THE SYMPTOMS

Symptoms include neck pain and tenderness, headaches that radiate to the back of the head, numbness down the arm and numbness in the fingers - typically the fourth and fifth fingers. Rarely there may be weakness of the hand.

Typically, the worst position is for a patient to lift the arm above the head during tasks such as hanging washing or brushing the hair.

WHAT CAUSES THORACIC OUTLET SYNDROME?

Thoracic outlet syndrome has no one definitive course. We suspect that some patients have a predilection for developing the syndrome.

Some patients have an extra rib, called a cervical rib, which narrows the space.

Patients may have had car accidents with associated whiplash; broken collar bones; had surgery on the shoulder or neck resulting in scar tissue that decreases movement of the nerves.

Body builders or athletes may build up big muscles which narrow the space and compress the nerves.

Thin patients with poor posture. A combination of factors usually causes the narrowing of the space and produces the symptoms.

HOW IS THORACIC OUTLET SYNDROME DIAGNOSED?

There is unfortunately no one confirmatory test for thoracic outlet syndrome. It is a diagnosis made by exclusion. Often patients have gone to many doctors and had many scans done looking at neck and shoulder problems and once these are excluded, thoracic outlet is suspected. Special x-rays will be done to look for any extra ribs and other possible bony causes of the pain.

HOW IS THORACIC OUTLET SYNDROME TREATED?

Conservative Management

Thoracic Outlet Syndrome needs to initially be treated by conservative means. This means intense physiotherapy to open up the space and release the nerves. This should be done in conjunction with muscle relaxants and analgesia. A trial period of at least three months should be given before embarking on surgery, unless there is obvious weakness and wasting of hand muscles.

Dr Redman works closely with physiotherapists who have an interest in thoracic outlet syndrome. This is important as physiotherapy needs to be very directed in these patients pre-and post-operatively.

Surgical Management

Should conservative management fail, then surgery is indicated.

Surgery entails removing the scalene muscles, removing an extra rib if it is present, and in some cases, removing the first rib.

Dr. Redman has been operating with Dr. Harris for three years in patients with thoracic outlet syndrome.

It is important to know that post-operatively the recovery period is long. Patients need post-operative physiotherapy with at least 2 to 3 weeks off work and physiotherapy for up to 3 months.

OUTCOMES

Outcomes of surgery are generally very good if patients are compliant with the rehabilitation. Immediate relief of pain and numbness may be experienced. In a few patients relief is not obtained and other causes need to be identified. This is to be expected in a small percentage of patients as there is no definitive diagnostic test.

ARTERIAL AND VENOUS THORACIC OUTLET SYNDROME

In the same way that the nerves may be compressed, the arteries and veins may be compressed as well.

This is much less common.

If the vein is compressed, then the patient may present with arm swelling or deep vein thrombosis.

If the artery is compressed, the patient may present with hand pain or even gangrene of the fingers.

These conditions may vary from benign to life-threatening and will require surgical intervention to open up the neck space and repair the vessels.