Thoracic outlet syndrome

Definition

Thoracic outlet syndrome is a combination of pain in the neck and shoulder, numbness and tingling of the fingers, and a weak grip. The thoracic outlet is the area between the rib cage and collar bone.

Causes, incidence, and risk factors

Thoracic outlet syndrome is a rare condition.

Blood vessels and nerves coming from the spine or major blood vessels of the body pass through a narrow space near the shoulder and armpit on their way to the arms. As they pass by or through the collarbone (clavicle) and upper ribs, they may not have enough space. Pressure (compression) on these blood vessels or nerves can cause symptoms in the arms or hands. Problems with the nerves account for almost all cases of thoracic outlet syndrome.

Compression can be caused by an extra cervical rib (above the first rib) or an abnormal tight fibrous band connecting the spinal vertebra to the rib. Patients often have a history of injury to the area or overuse of the shoulder.

People with long necks and droopy shoulders may be more likely to develop this condition because of extra pressure on their nerves and blood vessels.

Symptoms

Symptoms of thoracic outlet syndrome may include:

• Pain, numbness, and tingling in the last three fingers and inner forearm
• Pain and tingling in the neck and shoulders (carrying something heavy may make the pain worse)
• Signs of poor circulation in the hand or forearm
• Weakness of the muscles in the hand

Signs and tests

When you lift something, the arm may appear pale due to pressure on the blood vessels. Rarely, the arm may be smaller on the side of the symptoms. This is often present since birth (a congenital anomaly).

The diagnosis is typically made after the doctor takes a careful history and performs a physical examination. Sometimes tests are done to confirm the diagnosis, including the following:

• Electromyography (EMG)
• MRI
• Nerve conduction velocity study
• X-ray

Tests should also be performed to make sure there are no other problems, such as carpal tunnel syndrome or a damaged nerve due to problems in the cervical (neck) spine.

Treatment

Physical therapy helps strengthen the shoulder muscles, improve range of motion, and promote better posture. Treatment may also include pain medication.

Surgery may be recommended if physical therapy and changes in activity do not improve your symptoms. Types of procedures that might be performed include:

• An extra rib is removed and certain muscles are cut.
• A section of the first rib is removed to release pressure in the area.
• Bypass surgery is done to reroute blood around the compression or remove the area that is causing the symptoms.

Your doctor may also suggest other alternatives, including angioplasty.

Expectations (prognosis)

Having the fibrous band removed may eliminate symptoms if patients are selected carefully. Surgery can be successful in 50% to 80% of patients. Conservative approaches using physical therapy are helpful for many patients.

Complications

Complications can occur with any surgery and relate to the type of procedure and anesthesia used.

Damage to nerves or blood vessels may occur during surgery. This could lead to weakness of the arm muscles, or weakness of the muscles that help control the diaphragm when you breathe.

References

Smythe WR, Reznik SI, Putnam Jr. JB. Lung (including pulmonary embolism and thoracic outlet syndrome). In: Townsend Jr. CM, Beauchamp RD, Evers BM, Mattox KL. Sabiston Textbook of Surgery. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 59.