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Thoracic Outlet Syndrome (TOS)

Thoracic outlet syndrome (TOS) is a disorder that may compress the blood vessels or nerves in the upper chest region — called the thoracic outlet. This area is behind and below the collarbone opposite the first rib.

At the UPMC Division of Vascular Surgery, we take a team approach to quickly and correctly diagnose your TOS and create a treatment plan that’s right for you.

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What Is Thoracic Outlet Syndrome (TOS)?

Thoracic outlet syndrome (TOS) is a group of disorders in which pressure on the arteries, veins, or nerves causes symptoms in the thoracic outlet or upper chest region.

TOS may cause symptoms in the:

  • Arm
  • Hand
  • Neck
  • Upper back

Types of thoracic outlet syndrome

The three types of TOS include:

  • Arterial TOS affects the subclavian artery in the thoracic outlet.
  • Venous TOS affects the subclavian vein in the thoracic outlet.
  • Neurogenic TOS affects the brachial plexus in the thoracic outlet.

Causes and complications of thoracic outlet syndrome

TOS can occur on either side of the body, but most often affects the side of your dominant hand because of constant use.

Complications and symptoms vary depending on the type of TOS you have.

Arterial thoracic outlet syndrome

In arterial TOS, an artery in the thoracic outlet compresses, narrows, or dilates.

An extra rib (cervical) at the top of one’s rib cage or an abnormal first rib may cause this type of TOS.

Complications of arterial TOS can include:

A blood clot may break apart and smaller pieces — called emboli — can move down the arm.

This can block blood flow to the hand, causing:

  • Pain
  • Coolness
  • Numbness
  • Discoloration

It's vital to restore blood flow to the hand quickly.

Venous thoracic outlet syndrome

In venous TOS, a vein in the thoracic outlet becomes compressed and damaged. The most common cause is repetitive, strenuous use of the shoulder and arm.

Complications of venous TOS can include:

Neurogenic thoracic outlet syndrome

In neurogenic TOS, the brachial plexus — the bundle of nerves in the thoracic outlet — compresses, usually because of:

  • A prior injury.
  • Trauma.
  • Repetitive forces from exertional movements.

Neurogenic TOS complications can include:

  • Neck, arm, shoulder, or back pain that disrupts a person’s sleep, work, and daily activities.
  • Neck, arm, or shoulder weakness.
  • Nerve damage.

Thoracic outlet syndrome risks

TOS happens to people of all ages and both genders.

Factors that can increase your risk of TOS include:

  • Stress from repetitive tasks.
  • Playing a sport with repetitive arm motion — like baseball, volleyball, swimming, or tennis.
  • Having poor thoracic posture.
  • Prior cervical spine or neck trauma.

Why choose the UPMC Division of Vascular Surgery for thoracic outlet syndrome care?

Doctors from UPMC's Division of Vascular Surgery are experts in treating all types of TOS.

Our TOS experts

Thoracic Outlet Syndrome Symptoms and Diagnosis

Thoracic outlet syndrome (TOS) most often causes symptoms in the upper extremities, such as the:

  • Arm
  • Hand
  • Back
  • Neck

Symptoms vary based on the type of TOS.

Arterial thoracic outlet syndrome symptoms

Symptoms of arterial TOS include:

  • Pain, coldness, and paleness or change of color in the hand.
  • Cramping when using the arm.

Venous thoracic outlet syndrome symptoms

Symptoms of venous TOS include:

  • Swelling and dark color in the arm.
  • Arm pain.
  • Heaviness or fullness.
  • Dilated chest wall veins.

Neurogenic thoracic outlet syndrome symptoms

Symptoms of neurogenic TOS include:

  • Pain, numbness, tingling, or weakness in the arm and hand.
  • Pain that starts in the shoulder and moves down the arm into the fingertips.
  • Tired feeling in the arm.
  • Neck pain.
  • Headaches at the back of the head.

Thoracic outlet syndrome diagnosis

To confirm a diagnosis of TOS, your doctor at the UPMC Heart and Vascular Institute will begin by:

  • Talking with you about your TOS symptoms.
  • Reviewing your medical history.
  • Performing a thorough exam.
  • Asking you to perform exertional movements that may reproduce the symptoms.

Your doctor also may order heart imaging and other diagnostic tests, including:

  • X-rays of your neck and chest.
  • Ultrasound — uses ultrasound waves to create pictures of the blood flow through your blood vessels.
  • Nerve conduction velocity test — uses a low amount of electrical current to measure how fast an electrical impulse moves through a nerve.
  • Computerized tomography (CT) scan — uses cross-sectional x-rays and a computer to create detailed 3D images.
  • Magnetic resonance imaging (MRI) — uses a large magnetic field, radio waves, and computers to create detailed images.
  • Arteriography or venography — uses x-rays to view your arteries or veins. 

Learn More About Thoracic Outlet Syndrome Diagnostic Testing

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Thoracic Outlet Syndrome Treatment

The UPMC Heart and Vascular Institute’s vascular surgeons offer a range of treatments for arterial, venous, and neurogenic thoracic outlet syndrome (TOS).

Based on the type of TOS you have, we will provide a course of treatment that meets your needs.

Arterial thoracic outlet syndrome treatment

Surgery for arterial TOS

Your surgeon may operate to:

  • Repair your artery, if needed.
  • Expand the thoracic outlet.
  • Remove the first rib or cervical, if present.

Venous thoracic outlet syndrome treatment

Interventional procedures

  • Thrombolysis — a catheter delivers clot-busting drugs directly into the vein to break up a blood clot.
  • Venoplasty — doctors thread a balloon-tipped catheter into the vein and expand it to open up the vein.

Medical therapy

  • Anticoagulants, or blood thinners, to prevent new clots from forming.

Surgery for venous TOS

Your vascular surgeon may operate to:

  • Remove the blood clot.
  • Repair or replace the damaged vein.
  • Remove the abnormal rib.
  • Decompress (expand) the thoracic outlet.

Neurogenic thoracic outlet syndrome treatment

Physical therapy

  • To stretch the affected area, improving range of motion and strength.
  • Improve body posture and conditioning.
  • To show you how to avoid the motions that cause symptoms.
  • To assess your work site and suggest adjustments.

Medical therapy

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin or ibuprofen.
  • Pain relievers.

For those who fail to respond to conservative therapies, doctors may suggest surgery.

Surgical options for neurogenic TOS may include:

  • Expanding the thoracic outlet.
  • Removing the first rib.
  • Cleaning the scar tissue around the nerves. 

Learn More About Thoracic Outlet Syndrome Treatment

UPMC Patient Education Materials

UPMC's HealthBeat Blog

Learn More at UPMC Health Beat

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