Definition of Thoracic Outlet Syndrome

Thoracic outlet syndrome is a group of disorders that occur when the blood vessels or nerves in the thoracic outlet — the space between your collarbone (clavicle) and your first rib — become compressed. This can cause pain in your shoulders and neck and numbness in your fingers.

Common causes of thoracic outlet syndrome include physical trauma from a car accident and repetitive injuries from on-the-job or sports-related activities. Even an injury that happened long ago may lead to thoracic outlet syndrome in the present. Sometimes, doctors can't determine the cause of thoracic outlet syndrome.

Treatment for thoracic outlet syndrome usually involves physical therapy and pain relief measures. Most people improve with these conservative approaches. In some cases, however, your doctor may recommend surgery.

Symptoms of Thoracic Outlet Syndrome

Generally, there are three types (subdivisions) of thoracic outlet syndrome.

• Neurogenic (neurological) thoracic outlet syndrome. This form of thoracic outlet syndrome is characterized by compression of the brachial plexus. The brachial plexus is a network of nerves that come from your spinal cord and control muscle movements and sensation in your shoulder, arm and hand. In the majority of thoracic outlet syndrome cases, the symptoms are neurogenic.
• Vascular thoracic outlet syndrome. This type of thoracic outlet syndrome occurs when one or more of the arteries and veins under the clavicle (subclavian vessels) are compressed.
• Nonspecific-type thoracic outlet syndrome. This is also called disputed thoracic outlet syndrome or common thoracic outlet syndrome. Some doctors don't believe it exists, while others say it's a common disorder. People with nonspecific-type thoracic outlet syndrome have chronic pain in the area of the thoracic outlet, but the specific cause of the pain can't be determined.

Thoracic outlet syndrome symptoms can vary, depending on which structures are compressed. When nerves are compressed, signs and symptoms of neurologic thoracic outlet syndrome often include:

• Numbness or tingling in your fingers
• Pain in your shoulder and neck
• Ache in your arm or hand
• Weakening grip

Signs and symptoms of vascular thoracic outlet syndrome — compression of one or more of your veins and arteries — can include:

• Discoloration of your hand (bluish color)
• Subclavian vein thrombosis
• Arm pain and swelling, possibly due to blood clots
• Throbbing lump near your collarbone
• Lack of color (pallor) in one or more of your fingers or your entire hand
• Tiny black spots (infarcts) on your fingers

When to see a doctor
See your doctor if you consistently experience any of the signs and symptoms of thoracic outlet syndrome.

Causes of Thoracic Outlet Syndrome

In general, the cause of thoracic outlet syndrome is compression of the nerves and blood vessels in the thoracic outlet, just under your collarbone. The cause of the compression itself, however, can vary and can include:

• Anatomical defects. Inherited defects that are present at birth (congenital) may include a cervical rib — an extra rib located above the first 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 is often delayed.
• Repetitive activity. Doing the same thing over and over can, over time, 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 for extended periods, working on an assembly line, or stocking shelves and repeatedly lifting things above your head. Athletes, such as baseball pitchers and swimmers, also can develop thoracic outlet syndrome from years of repetitive movements. If you repeatedly carry heavy loads low on your body (rather than against your chest), you may also notice signs and symptoms of thoracic outlet syndrome.
• 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.

Complications

Thoracic outlet syndrome left untreated can cause permanent nerve damage; however, surgery to treat thoracic outlet syndrome is considered risky. This is because the procedure involves dividing a muscle in the neck and removing a portion of the first rib or repairing the brachial plexus nerves. For this reason, most doctors initially recommend a conservative treatment approach.

Tests and Diagnosis of Thoracic Outlet Syndrome

Diagnosing thoracic outlet syndrome can be difficult because the symptoms and severity of the symptoms can vary greatly among people with the disorder. To diagnose thoracic outlet syndrome, your doctor may first perform a physical examination to look for external signs of thoracic outlet syndrome, such as a depression in your shoulder, a pale discoloration in your arm, or a limited range of motion.

Your doctor will also ask you about your occupation, medical history and symptoms. He or she may conduct a number of provocation tests — tests designed to reproduce these symptoms. The tests may help your doctor determine the cause of your condition, and also will help rule out other causes that may have similar symptoms.

Some of the more common provocation tests that can suggest the presence of thoracic outlet syndrome include:

• Adson's maneuver. For this test, you'll be asked to turn your head toward the symptomatic shoulder while you extend your arm, neck and shoulder slightly away from your body. While you inhale, your doctor will check for a pulse on the wrist of your extended arm. If your pulse is diminished or if your symptoms are reproduced during the maneuver, your doctor considers this a positive test result, which may indicate thoracic outlet syndrome. Because false-positives often occur, your doctor may repeat the test on the unaffected side.
• Wright test. From a sitting position and with the help of your doctor, you'll hold your arm up and back (hyperabduction), rotating it outward, while your doctor checks your pulse to see if it's diminished. As in the Adson's maneuver, your doctor will want to know if your symptoms are reproduced during the test.
• Roos stress test. From a sitting position, your doctor will ask you to hold both elbows at shoulder height while pushing your shoulders back. You will then repeatedly open and close your hands for several minutes. If your symptoms are present after the test, or if you feel heaviness and fatigue in your shoulders, this can indicate the presence of thoracic outlet syndrome.

To confirm the diagnosis of thoracic outlet syndrome, your doctor may also order one or more of the following tests:

• X-ray. Your doctor may order an X-ray of the affected area, which may reveal an extra rib (cervical rib) and can also rule out other conditions that may be causing your symptoms.
• Magnetic resonance imaging (MRI) scan. MRI is a painless procedure that uses a magnetic field and radio waves to create computerized images of the soft tissues of your body. These images can help your doctor determine the location and cause of compressions of the brachial plexus nerves or the subclavian artery. The scans may also reveal any congenital anomalies — such as a fibrous band connecting your spine to your rib or a cervical rib — that may be the cause of your symptoms.
• Electromyography (EMG). Electomyography enables your doctor to see and hear how your muscles and nerves are working. To conduct the test, a small electrode needle is inserted through your skin and into the muscles near where you're having symptoms. The electrical activity detected by this electrode is displayed on a monitor and may be heard through a speaker.
• Nerve conduction study. Also called nerve conduction velocity, this test measures the speed of conduction of impulses through a nerve. Doctors use the test to evaluate possible nerve damage. Small electrodes are placed on your skin over the area being tested, and a tiny electrical current is sent to the nerves in your thoracic outlet. The electrical signals produced by nerves and muscles are picked up by a computer, and the information is interpreted by a doctor trained in electrodiagnostic medicine.

Treatments and Drugs for Thoracic Outlet Syndrome

In most cases, a conservative approach to treatment is effective, especially when the condition is diagnosed early. Conservative treatment for thoracic outlet syndrome may include:

• Physical therapy. You'll learn how to do exercises that strengthen your shoulder muscles to open the thoracic outlet, improve your range of motion and improve your posture. These exercises, done over time, will take the pressure off your blood vessels and nerves in the thoracic outlet.
• Relaxation. Techniques that help you relax, such as deep breathing, can keep you from tensing your shoulders and remind you to maintain good posture.
• Medications. Your doctor may prescribe pain medications, muscle relaxants and anti-inflammatory drugs — aspirin or ibuprofen (Advil, Motrin, others) — to decrease inflammation and encourage muscle relaxation.

If conservative treatments don't improve your symptoms or if you're experiencing signs of significant nerve damage, worsening muscle weakness or incapacitating pain, your doctor may recommend surgery. Your doctor may also recommend surgery if you've been diagnosed with true neurogenic thoracic outlet syndrome, in which case surgery is often the only treatment option.

Surgical options
Surgical treatment is usually effective in relieving the pain associated with thoracic outlet syndrome, but is often not as successful in treating muscle weakness, especially if the condition has gone untreated for an extended period of time.

A specialist in thoracic surgery or vascular surgery will perform the procedure. All surgical options to treat thoracic outlet syndrome pose a significant risk of injury to the brachial plexus. The most common surgical approaches for thoracic outlet syndrome treatment are:

• Anterior supraclavicular approach. This approach repairs compressed blood vessels. Your surgeon makes an incision just under your neck to expose your brachial plexus region. He or she then is able to look for signs of trauma or may discover fibrous bands contributing to compression near your first (uppermost) rib and can repair any compressed blood vessels.
• Transaxillary approach. In this surgery, your surgeon makes an incision in your chest to access the first rib, then removes a portion of the first rib to relieve compression. The advantage of this type of surgery is that it gives the surgeon easy access to the first rib without disturbing the nerves or blood vessels. But it also means the surgeon has limited access to the area's nerves and vessels, and most fibrous bands and cervical ribs that may be contributing to compression are hidden behind these nerves and blood vessels.

Lifestyle and home remedies

If you're diagnosed with thoracic outlet syndrome, your doctor or physical therapist will give you instructions on exercises to do at home to strengthen and support the muscles surrounding your thoracic outlet. To avoid unnecessary stress on your shoulders and muscles surrounding the thoracic outlet:

• Maintain good posture
• Take frequent breaks at work
• Practice relaxation techniques

Coping and support

Symptoms associated with thoracic outlet syndrome can be caused by a number of other conditions, which makes it difficult for doctors to diagnose. Many people experience symptoms of thoracic outlet syndrome for years before they are diagnosed with the condition, which can cause stress and frustration.

Be sure to discuss your concerns with your doctor if your symptoms persist and a diagnosis hasn't been made. Getting a second opinion from another doctor may put your mind at ease and allow you to focus on getting better.

Prevention

Thoracic outlet syndrome that goes untreated for years can cause permanent neurological damage, so it's important to deal with the symptoms early or, more important, to prevent the disorder altogether. If you're susceptible to thoracic outlet syndrome, avoid repetitive movements and lifting heavy objects. If you're overweight, you can prevent or relieve symptoms associated with thoracic outlet syndrome by losing weight.

Even if you don't have symptoms of thoracic outlet syndrome, avoid carrying heavy bags over your shoulder, because this can increase pressure on the thoracic outlet. Stretch daily, and perform exercises that keep your shoulder muscles strong.