What is thoracic outlet syndrome?
Your thoracic outlet is a small space just behind and below your
collarbone. The blood vessels and nerves that serve your arm are
located in this space. Thoracic outlet syndrome (TOS) is the presence
of hand and arm symptoms due to pressure against the nerves or blood
vessels in the thoracic outlet area.
There are three types of TOS. The type depends on which structure is
compressed -- nerve, vein, or artery. Ninety-five percent of cases of
TOS are due to compression of the nerves to the arm (called neurogenic TOS). Three to 4 percent are due to obstruction or clotting of the main vein to the arm, the subclavian vein, a condition called venous TOS. The third type, arterial TOS,
is the rarest type, occurring in 1 percent of cases, and it is due to
disease in the artery leading to the arm, the subclavian artery.
Almost all cases of arterial TOS are associated with an extra rib
(cervical rib) or an abnormal first rib.
What are the symptoms?
The common symptoms depend on which structure is being compressed. In neurogenic TOS,
the symptoms are pain, numbness, tingling, and/or weakness in the arm
and hand. Also common is a tired feeling in your arm, which is made
worse by working with your arms raised over your head. Neck pain and
headaches in the back of your head are also frequent symptoms. Another
common occurrence is pain that starts in your shoulder and runs down
your arm, as well as pain in your fingertips. Unfortunately, the
symptoms of neurogenic TOS can be vague and non-specific. Venous TOS is distinguished by swelling in your entire arm, plus pain and dark discoloration. Arterial TOS presents with pain, coldness, and a pale discoloration of the hand. Cramps occur when using the arm for activity.
What causes thoracic outlet syndrome?
Neurogenic TOS is most often the result of neck
trauma such as a whiplash injury. Slipping and falling on floors or
ice, or repetitive stress from working on assembly lines or keyboards
are the next most common causes. The symptoms are due to scar tissue
formation in neck muscles (called scalene muscles).
Venous TOS is commonly due to strenuous use of the
arm and shoulder. Its underlying cause is congenital narrowing of the
space through which the major arm vein (subclavian vein) passes from
the shoulder area into the heart.
Arterial TOS is caused by a narrowing in the main
artery to the arm (subclavian artery) which invariably is secondary to
a congenital extra rib (cervical rib) which lies at the base of the
neck, just above the highest rib in your chest, or it can be secondary
to an abnormal first rib. Once the artery has been narrowed, one of two
things will happen. The artery may enlarge, forming an aneurysm just
beyond the narrowing, and a clot will form in the wall of the aneurysm;
or the artery may remain narrowed and a clot will form inside the
artery just beyond the narrowing. The danger of the clot is that pieces
of it will break off (called emboli) and travel down the arm to block
the circulation to your hand. When this occurs, the hand becomes cold,
numb, painful, and discolored and you are in danger of losing your hand
completely. Treatment to restore circulation is essential.
What tests will I need?
Diagnosing TOS can be complex. It begins by your physician asking
you a series of questions to find out your symptoms and how the
symptoms began. Depending on your symptoms, your doctor will be able to
tell if you might have a nerve, vein, or artery problem which will then
lead to an appropriate physical examination.
For neurogenic TOS, your physician will have you
perform a number of provocative maneuvers. These consist of putting
your neck and arms in different positions of stress to try to reproduce
your symptoms. Other physical findings include tenderness in certain
places in your neck, chest, or arms.
For venous TOS, physical examination consists
primarily of noting swelling in your arm and prominent veins seen just
under the skin at the spot where your shoulder joins your chest.
In arterial TOS, physical exam often finds the
pulse at your wrist is diminished or absent. Your hand may have a pale
color compared to your pink, good hand.
However, venous and arterial TOS are best diagnosed with the aid of
specific tests, venography for venous TOS and pulse volume recordings
or arteriography for arterial TOS.
To help determine whether or not you have TOS, your physician may order one or more of the following tests:
How is thoracic outlet syndrome treated?
Your particular treatment will depend on the type of TOS you have,as
determined by your symptoms, physical examination and test results.
Neurogenic TOS is initially treated with physical
therapy. The basic therapy methods include stretching exercises of your
neck, posture correction, learning to avoid specific movements that
bring on or aggravate your symptoms, and modifying your work site when
appropriate. While some therapists may suggest strengthening exercises,
most patients with neurogenic TOS are made worse by strengthening
exercises. Treatment with a therapist for a few weeks is usually
followed by a home exercise program which you continue on your own for
at least several more weeks.
Your physician may also prescribe medications such as muscle
relaxants, non-steroidal anti-inflammatory drugs such as aspirin or
ibuprofen, pain relievers, or steroids. In addition, some patients get
relief by applying moist heat or massaging the affected area.
When treatment begins in the early stages of neurogenic TOS, most
patients improve with the measures listed above. However, if your TOS
symptoms do not improve with these measures, and if your symptoms are
interfering with sleep, work, recreation, or activities of daily
living, your physician may consider more aggressive therapy. Your
vascular surgeon may recommend TOS decompression surgery that involves
removing certain muscles in your neck, removing your first rib, or a
combined operation to remove both muscles and rib.
Venous TOS is not treated with physical therapy.
Rather, the clot in the vein is initially treated with clot dissolving
medication (called thrombolysis), with blood thinners (anticoagulants),
or sometimes treated by surgically opening the vein and removing the
clot. Once the clot has been removed, your surgeon may recommend that
the first rib be removed so that the narrow space through which the
vein passed can be enlarged to prevent the vein from clotting again. If
the vein is badly narrowed, the narrow spot can be widened by having a
balloon stretch out the vein, a procedure called an angioplasty.
Arterial TOS is treated in a very different way. If
the subclavian artery in your thoracic outlet has become damaged by
pressure, your vascular surgeon must repair the artery or replace it
with an arterial graft. The replacement graft may be a vein from
another part of your body or a plastic artery substitute. In addition
to fixing the damaged artery, the abnormal rib must be removed to
prevent the artery from being damaged again. Your vascular surgeon can
perform all of this in one operation.
What can I do to stay healthy?
You can improve your recovery from TOS by practicing good posture,
taking frequent breaks from work to stretch, and losing weight if you
are overweight. Also, if you are prone to TOS, it is wise to avoid
repetitive lifting of heavy objects over your head.