What is Thoracic Outlet Syndrome?
The term, Thoracic Outlet Syndrome, relates to a group of disorders that occur due to compression of structures that enter the chest from the neck. The thoracic outlet is found between the collar bone and the first rib. The affected structures are usually the nerves of the brachial plexus, and or the veins and arteries. This can be caused by repetitive movement injuries, anatomical variations such as an extra rib and physical trauma.
Symptoms of this disorder can include shoulder pain, neck pain, and weakness, numbness and coldness in the arm and hand. These symptoms can come on slowly or appear suddenly. This condition can become chronic and last for many years. Recovery can be hastened by accurate diagnosis and high-quality rehabilitation.
Diagnosis of Thoracic Outlet Syndrome is dependent on the correct interpretation of symptoms from your medical history and a physical examination. Once thoracic outlet syndrome is suspected, medical imaging may be undertaken to confirm diagnosis and ascertain which structure is compressed and why this is happening. Diagnostic tests that give us the required information can include radiographs (X-ray), ultrasound, CT, MRI, arteriography and venography (imaging of the arteries or veins with dye) and electromyography (EMG).
Types of Thoracic Outlet Syndrome
Thoracic outlet syndrome refers to the compression, irritation or injury of the nerves and/or blood vessels as they come down from the neck into the chest through the thoracic outlet- the space between the collar bone and 1st rib (as shown in the picture).
Thoracic outlet syndrome is divided into 3 different types which can co-exist together or occur in isolation.
This type involves compression of the brachial plexus (the group of nerves supplying the arm). This can cause pain, pins and needles, tingling or numbness in the neck, shoulder, arm or hand as well as weakness of hand grip.
This type compresses the subclavian artery (the major blood supply to the arm as well as partial supply of the neck and brain). This can cause cold, pale appearance and reduced pulse to the fingers, hands or arms and sometimes also hand and arm pain.
This type compresses the subclavian vein (the vein that drains the blood from the arm). This can case discolouration of the hands or arms (pale or blue), arm pain and swelling, fatigue with activity, or even a blood clot.
Neurogenic, arterial and venous types are all usually aggravated by elevation of the arm which causes compression of the thoracic outlet.
Risks with Thoracic Outlet Syndrome
Thoracic Outlet Syndrome, being a group of disorders, has a wide range of risk factors leading to the development of symptoms. Females are significantly more likely than males to be affected, with the bulk of diagnoses being made in people aged between 20 and 50.
- Inherited anatomical variations such as an extra rib originating from the neck vertebrae (cervical rib) or tight connective tissue in the region of the thoracic outlet.
- Poor posture due to sitting with rounded shoulders and the neck being held in a forward position. This can occur with jobs that require prolonged periods of sitting and the use of laptop computers, rather than desktop set ups.
- Jobs and pastimes with repetitive movements and the lifting of heavy items.
- Carrying of bags on one shoulder, as the strap will create a load over the region of the thoracic outlet.
- Car accidents, falls and chronic pain from repetitive injuries can cause changes in the tissues of the thoracic outlet. These changes can occur over time and may not be clear initially after an injury. Slow onset symptoms are often ignored, leading to longer recovery times.
Prevention of Thoracic Outlet Syndrome can be as simple as changing your lifestyle to avoid the above risk factors as much as possible. For people undertaking jobs and sports with repetitive, heavy lifting, it is imperative that you ensure that your body is strong and conditioned to lift loads that are higher than the ones that are experienced daily. If you are stronger than your job requires, then you create a protective mechanism that helps avoid a variety of injuries.
Treatment of Thoracic Outlet Syndrome
The treatment of Thoracic Outlet Syndrome (TOS) will depend on whether it is neurogenic or vascular. It is important that Thoracic Outlet Syndrome has been diagnosed properly.
For Neurogenic TOS (the most common type), usually physiotherapy is very effective and should be the first line of treatment. Physiotherapy will help to increase the space at the thoracic outlet by increasing the range of movement and strength of the neck and shoulders and improving posture.
Sometimes doctors may prescribe medications to assist with the recovery including pain relief, anti-inflammatories or muscle relaxants. In rare cases if conservative measures haven’t been effective, then decompression surgery may be required to remove the first rib, abnormal muscles or any fibrous bands that may be obstructing the thoracic outlet.
In the cases of Venous TOS, treatment will depend on the severity. If a blood clot is present your doctor may prescribe thrombolytic and anti-coagulant medications to break up the clot. Decompression surgery may be necessary to open up the thoracic outlet. In more mild cases physiotherapy may be effective.
For Arterial TOS (the most rare type), decompression surgery is often necessary. Although as per in Venous TOS, in more mild cases physiotherapy may be effective.