What is Thoracic Outlet Syndrome?
The thoracic outlet is the narrow space between your collarbone and first rib.. Thoracic outlet syndrome (TOS) refers to a group of disorders that occur when there is compression, injury, or irritation of the nerves and/or blood vessels (arteries and veins) in the lower neck and upper chest area. The increased pressure on the blood vessels and nerves may cause pain in your shoulders, neck, and arms. It can also cause numbness or tingling in your hands.
It is felt by some scientists that the evolution of the torso of primates from a four-legged to a two-legged position may predispose humans to the development of thoracic outlet syndrome. The resulting vertical posture produced flattening of the chest cage and a shift of the shoulder joint backward, both of which narrowed the thoracic outlet.
What are the Symptoms?
The symptoms that you experience as a result of thoracic outlet syndrome will depend on whether the nerves or the blood vessels are affected.
When nerves are compressed, signs and symptoms of neurological thoracic outlet syndrome include:
- Muscle wasting in the fleshy base of your thumb (Gilliatt-Sumner hand)
- Numbness or tingling in your arm or fingers
- Pain or aches in your neck, shoulder or hand
- Weakness of the hand and a weakened grip
When blood vessels are compressed, signs and symptoms of vascular thoracic outlet syndrome can include:
- Discoloration of your hand (bluish color)
- Arm pain and swelling, possibly due to blood clots
- Blood clot in veins or arteries in the upper area of your body
- Lack of color (pallor) in one or more of your fingers or your entire hand
- Weak or no pulse in the affected arm
- Cold fingers, hands or arms
- Arm fatigue with activity
- Numbness or tingling in your fingers
- Weakness of arm or neck
- Throbbing lump near your collarbone
You may also find it difficult to lift objects above your head. You might also have a limited range of motion in your shoulders and arms.
What are the Causes?
The cause of thoracic outlet syndrome is not well understood, and isn’t always known. However, common causes of thoracic outlet syndrome include physical trauma from a car accident, repetitive injuries from job- or sports-related activities, certain anatomical defects (such as having an extra rib), and pregnancy.
In general, the cause of thoracic outlet syndrome is compression of the nerves or blood vessels in the thoracic outlet, just under your collarbone (clavicle). The cause of the compression varies and can include:
- Anatomical defects. Inherited defects that are present at birth (congenital) may include an extra rib located above the first rib (cervical rib) or an abnormally tight fibrous band connecting your spine to your rib.
- Poor posture. Drooping your shoulders or holding your head in a forward position can cause compression in the thoracic outlet area.
- Trauma. A traumatic event, such as a car accident, can cause internal changes that then compress the nerves in the thoracic outlet. The onset of symptoms related to a traumatic accident often is delayed.
- Repetitive activity involving the shoulders and arms. Over time, doing the same thing repeatedly can wear on your body’s tissue. You may notice symptoms of thoracic outlet syndrome if your job requires you to repeat a movement continuously, such as typing on a computer, working on an assembly line or lifting things above your head, as you would if you were stocking shelves. Athletes, such as baseball pitchers and swimmers, also can develop thoracic outlet syndrome from years of repetitive movements.
- Pressure on your joints. Obesity can put an undue amount of stress on your joints, as can carrying around an oversized bag or backpack.
- Pregnancy. Because joints loosen during pregnancy, signs of thoracic outlet syndrome may first appear while you’re pregnant.
In addition, the following may increase the risk of developing thoracic outlet syndrome:
- Sleep disorders
- Tumors or large lymph nodes in the upper chest or underarm area
- Stress or depression
- Participating in sports that involve repetitive arm or shoulder movement, such as baseball, swimming, golfing, volleyball and others
- Repetitive injuries from carrying heavy shoulder loads
- Injury to the neck or back (whiplash injury)
What are the Risk Factors?
There are several risk factors that seem to increase the risk of thoracic outlet syndrome, including:
- Sex. Females are far more likely to be diagnosed with thoracic outlet syndrome than are males.
- Age. Thoracic outlet syndrome is more common in young adults, between 20 and 40 years old.
- Certain occupations. Occupations that involve heavy usage of the upper extremities against resistance, including jack-hammer operators and dental hygienists, weight lifting, pregnancy, and obesity. Any condition that causes encroachment of the space for the brachial plexus at the thoracic outlet can lead to thoracic outlet syndrome, including poor posture.
What are the Treatments?
In most cases, a conservative approach to treatment is taken for thoracic outlet syndrome, and usually involves physical therapy and pain relief measures. Most people improve with these approaches. In some cases, however, your doctor may recommend surgery. The goal of treatment for thoracic outlet syndrome is to ease symptoms and pain. The specific type of treatment used may vary depending on the cause and severity of the condition. You and your doctor can discuss which treatment option is best for you.
Treatment may include:
- Physical therapy. If you have neurogenic thoracic outlet syndrome, physical therapy is the first line of treatment. You’ll learn how to do exercises that strengthen and stretch your shoulder muscles to open the thoracic outlet, improve your range of motion and improve your posture. These exercises, done over time, may take the pressure off your blood vessels and nerves in the thoracic outlet.
- Medications. Your doctor may prescribe anti-inflammatory medications, pain medications or muscle relaxants to decrease inflammation, reduce pain and encourage muscle relaxation.
Clot-dissolving medications. If you have venous or arterial thoracic outlet syndrome and have blood clots, your doctor may administer clot-dissolving medications (thrombolytics) into your veins or arteries to dissolve blood clots. After you’re given thrombolytics, your doctor may prescribe medications to prevent blood clots (anticoagulants).
- Weight loss program. If you’re overweight, your doctor may recommend a weight-loss program or specific diet to help relieve symptoms. Maintaining a healthy weight is important for reducing pressure on the joints.
Your doctor may recommend surgery if other treatment hasn’t been effective, if you’re experiencing ongoing symptoms or if you have progressive neurological problems. Surgery for thoracic outlet syndrome might involve removing an extra rib, removing a section of the first rib, or rerouting blood vessels around the thoracic outlet. If the vessels in the thoracic outlet are severely narrowed, angioplasty may be used to open them up. During angioplasty, tiny balloons are used to inflate the narrowed vessels. A surgeon trained in chest (thoracic) surgery or blood vessel (vascular) surgery will perform the procedure.
Thoracic outlet syndrome surgery has risks of complications, such as injury to the brachial plexus. Also, surgery may not relieve your symptoms, and symptoms may recur.
Surgery to treat thoracic outlet syndrome, called thoracic outlet decompression, may be performed using several different approaches, including:
- Transaxillary approach. In this surgery, your surgeon makes an incision in your chest to access the first rib, divide the muscles in front of the rib and remove a portion of the first rib to relieve compression. This approach gives your surgeon easy access to the first rib without disturbing the nerves or blood vessels. But, that only gives your surgeon limited access and makes it harder to see muscles and cervical ribs that may be contributing to compression behind the nerves and blood vessels.
- Supraclavicular approach. This approach repairs compressed blood vessels. Your surgeon makes an incision just under your neck to expose your brachial plexus region. Your surgeon then looks for signs of trauma or muscles contributing to compression near your first (uppermost) rib. Your surgeon may remove the muscles causing the compression and repair compressed blood vessels. Your first rib may be removed if necessary to relieve compression.
- Infraclavicular approach. In this approach, your surgeon makes an incision under your collarbone and across your chest. This procedure may be used to treat compressed veins that require extensive repair.
In venous or arterial thoracic outlet syndrome, your surgeon may deliver medications to dissolve blood clots prior to thoracic outlet compression. Also, in some cases, your surgeon may conduct a procedure to remove a clot from the vein or artery or repair the vein or artery prior to thoracic outlet decompression.
If you have arterial thoracic outlet syndrome, your surgeon may need to replace the damaged artery with a section of an artery from another part of your body (graft) or an artificial graft. This procedure may be done at the same time as your procedure to have the first rib removed.