Thoracic outlet syndrome, also known as TOS, is a condition that causes symptoms in the arm secondary to pressure on structures running between the collarbone and the first rib (thoracic outlet). Generally, it is confused with other conditions causing pressure on nerves and blood vessels in the neck and arm. One cause of TOS is cervical rib syndrome, but there are other causes. What is thoracic outlet syndrome, and how do we treat it?
What is s a cervical rib?
Ususally, the rib cage contains 12 ribs. A cervical rib is an extra rib from the cervical spine that sits above the first rib. These extra bone growths form from the traverse processes of the C7 vertebrae. They occur in less than 1% of the population. Most of these extra bones don’t cause problems. However, in some cases, they compress the thoracic outlet contributing to the development of thoracic outlet syndrome.
Thoracic outlet syndrome
A complex set of nerves and vessels pass through a hole or ‘outlet.’ The boundaries of the hole are the first rib of the chest wall, the collarbone, and the muscles of the neck (called scalene muscles). Pressure on these structures can cause symptoms ranging from a pinched nerve (leading to pins and needles, numbness, and weakness of pain) to pinched vessels (causing swelling, discolouration, and change in temperature).
Causes
Causes of pressure in the outlet can be traumatic or overuse. Examples of trauma include a break in the collarbone leading to pressure from a bone sticking into the outlet. Overuse conditions include repetitive overhead movements or sports. Sometimes, people with an extra rib, called a cervical rib, can narrow the outlet.
How to diagnose thoracic outlet syndrome
Symptoms depend on the type of compression you have. Generally, we think there are three varieties of compression:
- Neurogenic compression is caused by pinching of the brachial plexus nerves leading to pins and needles, numbness, and clumsiness or weakness of the hand. Sometimes pain can extend to the chest, under the armpit, or head.
- Arterial compression is caused by compression of the large artery or subclavian vein, producing coldness, numbness, and pain in the finger.
- Venous compression caused by pressure on the bog vein leading to swelling of the arm, an increase in the size of chest veins, and a heavy sensation in the arm
Generally, we suggest a thorough examination to confirm our thinking and exclude other causes. Firstly, we start with a complete neck, arm, and wrist assessment. Pressing on the compressed structures in the neck or chest can produce symptoms. Next, we use a group of tests (Roo’s and Adson’s tests) to check the strength of the wrist pulse in certain arm positions. A loss of a wrist pulse suggests TOS. Also, nerve testing is essential to look for a pinched nerve and other causes of your symptoms.
Generally, tests such as MRI of the neck and outlet, nerve studies, and blood vessel studies are done. Sometimes, a local anesthetic injection near the neck can help localise the pressure site.
Difficult diagnosis
Often, making a diagnosis is difficult. Early symptoms are similar to other conditions, such as
- Pinching of the nerves in the arm or wrist, such as carpal tunnel syndrome or cubital tunnel syndrome
- Nerve pinching in the neck from a herniated disc
- Inflammation of the nerves of the brachial plexus, also called brachial neuritis.
Thoracic outlet syndrome vs. cervical radiculopathy
Telling the differences between these two conditions is difficult. Generally, people with cervical radiculopathy have a painful neck, and movement of the neck brings on the pain. Also, a herniated disc does not cause vessel problems such as discoloration, swelling of the arm, or tiredness with arm movement. Nonetheless, it is still challenging to separate these conditions.
Treatment
Cervical rib syndrome
If a cervical rib is causing compression of the thoracic outlet, physiotherapy can help improve neck mobility and reduce muscle tension. Other treatments include injections such as botox or local anesthetic into the scalene muscles to reduce muscle tension.
Surgical excision is performed if these methods fail to reduce pressure on the nerves or vessels. Sometimes, excision of the scalene muscles is also used to open the outlet further and relieve pressure. Some surgeons think you need to excise both the cervical and the first rib to get the best results.
Thoracic outlet obstruction
Generally, simple treatments are tried first, particularly in the neurogenic type.
Examples of simple treatments tried by your physiotherapist include soft tissue massage and stretching of the muscles surrounding the outlet. Targets include the pectoral, trapezius, and scalene muscles. Also, strengthening the shoulder and rotator cuff muscles improves posture and reduces pressure in the outlet. Finally, nerve gliding techniques for the upper limb will help floss the nerves and stop them from getting stuck.
Secondly, medications for nerve pinching might help reduce pinching symptoms. Examples include amitriptyline or gabapentin.
Thoracic outlet syndrome sleeping position
It is important to avoid sleeping positions that increase the pressure on the outlet. Generally, we recommend sleeping on your back or with two pillows on the affected side to prevent compression of the outlet.
Thoracic outlet syndrome Surgery
If left untreated, permanent damage can occur to the nerves and vessels of the outlet. Sometimes, blood clots can form in the veins putting your life in danger. Generally, we recommend surgery if 3-6 months of physio fails or you develop signs of vessel compression.
Final word from Sportdoctorlondon on cervical rib and thoracic outlet syndrome
Thoracic outlet obstruction is a complex condition to diagnose. Usually, it is confused with other conditions, such as a herniated disc in the neck or carpal tunnel syndrome. But, significantly, early diagnosis can reduce permanent damage to the nerves and vessels.
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