Thoracic Outlet Syndrome

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Thoracic outlet syndrome (TOS) consists of a group of distinct disorders

that affect the nerves in the brachial plexus (nerves that pass into the

arms from the neck) and various nerves and blood vessels between the base

of

the neck and axilla (armpit). For the most part, these disorders have very

little in common except the site of occurrence. The disorders are complex,

somewhat confusing, and poorly defined, each with various signs and

symptoms

of the upper limb.

True neurologic TOS is the only type with a clear definition that most

scientists agree upon. The disorder is rare, typically painless, and caused

by congenital anomalies (unusual anatomic features present at birth). It

generally occurs in middle-aged women and almost always on one side of the

body. Symptoms include weakness and wasting of hand muscles, and numbness

in

the hand.

Disputed TOS, also called common or non-specific TOS, is a highly

controversial disorder. Some doctors do not believe it exists while others

say it is very common. Because of this controversy, the disorder is

referred

to as " disputed TOS. " Many scientists believe disputed TOS is caused by

injury to the nerves in the brachial plexus. The most prominent symptom of

the disorder is pain. Other symptoms include weakness and fatigue.

Arterial TOS occurs on one side of the body. It affects patients of both

genders and at any age but often occurs in young people. Like true

neurologic TOS, arterial TOS is rare and is caused by a congenital anomaly.

Symptoms can include sensitivity to cold in the hands and fingers, numbness

or pain in the fingers, and finger ulcers (sores) or severe limb ischemia

(inadequate blood circulation).

Venous TOS is also a rare disorder that affects men and women equally. The

exact cause of this type of TOS is unknown. It often develops suddenly,

frequently following unusual, prolonged limb exertion.

Traumatic TOS may be caused by traumatic or repetitive activities such as a

motor vehicle accident or hyperextension injury (for example, after a

person

overextends an arm during exercise or while reaching for an object). Pain

is

the most common symptom of this TOS, and often occurs with tenderness.

Paresthesias (an abnormal burning or prickling sensation generally felt in

the hands, arms, legs, or feet), sensory loss, and weakness also occur.

Certain body postures may exacerbate symptoms of the disorder.

Treatment for individuals with TOS varies depending on the type. True

neurologic TOS is generally effectively treated with surgery. Most other

forms need only symptomatic treatment. Common or disputed TOS requires

conservative treatment which may include drugs such as analgesics, and

physical therapy to increase range of motion of the neck and shoulders,

strengthen muscles, and induce better posture. Some cases of disputed TOS

may require surgery (although, like the diagnosis, surgery is

controversial). Heat, analgesics, and shoulder exercises have been used

with

limited success in individuals with traumatic TOS. Surgery may be needed in

some cases. Vascular TOS often requires surgery.