DR HQ: Anatomy 101— Thoracic Outlet Syndrome

What is thoracic outlet syndrome?

This is a tough one. Thoracic outlet syndrome (TOS) is a complicated medical condition that requires some explaining. The thoracic outlet is part of the name is for a space in the upper chest and lower neck region. This region has a multitude of nerves and vessels that goes through this part of the body. Syndrome means a group of symptoms that can occur as a result of something goes on in this part of the body.

Venous and Arterial thoracic outlet syndrome are more specific conditions similar to TOS but aren’t as common. Our focus today is on TOS as it relates to baseball players.

What is the cause of thoracic outlet syndrome?
Doctors don’t have all the reasons why a player suffers this malady. They do know this: When blood vessels and or nerves are compressed in the area of the body known as the thoracic outlet, they become irritated and the end result can be TOS. This compression can come from an old fracture of the clavicle (collarbone). Sometimes the cause is an extra first rib called a cervical rib. This reduces the space the nerves and or vessels have in the thoracic outlet. Soft tissue problems or bony protrusions also can contribute to TOS. Lastly, another contributing factor is the repetitive motion that a baseball player, especially a pitcher, puts his body through.

Courtesy: www.mybwdoc.com

Specifically, the most common type of thoracic outlet syndrome is neurogenic thoracic outlet syndrome. The player in question has pressure on the nerves on the thoracic outlet region. This pressure compresses and irritates the nerves that in turn cause a reduction in motor skills of the arm and hand. He also is likely to have some loss of feeling in his fingers and hand.

Signs and Symptoms of TOS?
The player may feel neck shoulder or arm pain. Numbness in the hand, fingers and forearm also can be a sign of TOS. A pitcher complaining of numbness or a sense of cold also can have TOS. But a wide range of other conditions cause the same symptoms. That’s what makes this ailment so difficult to diagnose. Also lurking in the background is that the pain associated with TOS can be mistaken as angina (chest pain due to a lack of oxygen to the heart). When the player lifts his arm, the pain can increase and that’s with both heart problems and TOS. 

How common is TOS?
TOS is not very common in the baseball population and almost never see more than 1-3 cases a year in both the majors and minors. We’ll look at the latest major league pitcher to suffer from this ailment—Shawn Marcum—in a moment.   

Diagnosing and treating TOS can be a huge undertaking. Look at the possible tests that are performed to help determine if it is indeed TOS:

  • Chest X-ray to rule out cervical rib abnormalities
  • Cervical spine X-rays to rule out a cervical rib (extra rib) or cervical (neck) spine abnormalities
  • Computed tomography (CT) scan and magnetic resonance imaging (MRI) of the chest
  • CT scan or MRI of the spine to rule out cervical spine impingement (pressure), which can mimic neurogenic thoracic outlet syndrome
  • Magnetic resonance imaging with angiography (MRA) to view blood vessels
  • Arteriogram/venogram (X-ray that uses dye to look at blood flow)
  • Vascular studies (of the arteries or veins)
  • Nerve conduction studies (to evaluate the function of the motor and sensory nerves)
  • Blood tests

How is TOS treated?
Physical therapy is the first area of concentration along with medication. If the physician can find a way to reduce the compression on the nerves and/or blood vessels, the player's symptoms may subside and he’ll regain strength. If this doesn’t provide relief, surgery is usually performed to relieve the pressure, clean up and scar tissue that may have developed so normal blood flow or nerve function can return with the rehabilitation process.

As far as we know, Shaun Marcum (RHP, NYM) has not suffered a fractured clavicle (collarbone). However, he was diagnosed early in spring training with right shoulder impingement. Then it was changed to a pinched nerve when the neurological tests came back positive. Finally in early July, he was diagnosed with thoracic outlet syndrome after a battery of tests ruled just about everything else. Even after the player has had surgery, its not a guarantee he will recover and pick up his career where he left off. A lot of players do not regain all the strength and or feeling in their fingers, hand or forearm.

It's a very difficult malady to recover completely from. Jarrod Saltamacchia recovered from successful surgery for TOS, as did pitchers Kenny Rogers, Matt Harrison and Jeremy Bonderman—but in Bonderman’s case, other issues on top of the TOS have kept him from pitching effectively at the major league level. Aaron Cook, Chris Carpenter, Noah Lowry and Kip Wells are others that have had various amounts of success returning from TOS.

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  For more information about the terms used in this article, see our Glossary Primer.