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.
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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.
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The prognosis for individuals with TOS varies
according to the type. For the majority of individuals who receive
treatment the prognosis for recovery is good.
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Within the NINDS research programs, TOS is addressed
through research on pain. NINDS vigorously pursues a research
program seeking new treatments for pain and nerve damage with the
ultimate goal of reversing disorders such as TOS.
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American Chronic Pain Association
(ACPA)
National Rehabilitation Information
Center (NARIC)
National Chronic Pain
Outreach Association (NCPOA)
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