Thoracic Outlet Syndrome

Definition

The thoracic outlet itself is the area between the neck and shoulder. Thoracic outlet syndrome (TOS) is a group of conditions caused by the compression of nerves or blood vessels in the thoracic outlet. The compression can cause shoulder and neck pain. It can also lead to numbness in the fingers, a weak grip, cold hands and swelling.

Potential causes

There are many potential causes, such as whiplash or other trauma from a car accident, bad posture, pregnancy, heavy lifting or even the anatomical abnormality of having an extra rib. But baseball pitchers are particularly susceptible to it.

For one, pitchers’ training methods enlarge the muscles in the neck and pectorals, crowding that thoracic outlet space and potentially leading to compression. Also, the repetitive overhead motions of pitching -- especially at high velocity -- causes stress on the joints, muscles and soft tissues and can lead to abnormal positioning of the collarbone. If the collarbone shifts too close to the first rib, it can compress the nerves in that area, causing TOS.

Different types of TOS

Neurogenic TOS: A compression of the nerves. Most pitchers who deal with TOS have neurogenic TOS.

Venous TOS: A compression of the vein between the collarbone and first rib. It requires quicker medical intervention than neurogenic TOS because of the threat of blood clots that can block blood flow in the arm or hand or to the lungs. However, surgically addressing venous TOS is generally seen as having a more predictable outcome than neurogenic TOS.

Arterial TOS: A compression of the artery. It's the rarest form of TOS, leading to coldness in the hand or even finger gangrene.

Treatment

TOS can be treated first with physical therapy to strengthen and stretch the shoulder muscles and open the thoracic outlet, taking pressure off the blood vessels and nerves. For venous TOS, blood thinners and lifestyle changes can help manage symptoms. Quite often, though, baseball pitchers diagnosed with TOS require surgery.

TOS surgery is called decompression. Typically, the first rib is removed, as are the neck muscles contributing to the compression. Venous TOS patients (Phillies ace Zack Wheeler as an example) typically need a procedure to remove the blood clot first, prior to the decompression surgery.

Recovery time

It depends on the severity of the case and the type of TOS, but a typical recovery period for a pitcher is about nine or 10 months.