Introduction to Thoracic Outlet Syndrome

Incidence of Thoracic Outlet Syndrome

Because thoracic outlet syndrome (TOS) is thought by some experts to be underdiagnosed and in some cases misdiagnosed, it is difficult to estimate with any degree of accuracy how many people suffer from this condition. The incidence of TOS in the U.S. population has been broadly estimated to range from 0.3% to 8%. The most common age range is 25 to 40 years and women are affected about 4 times more frequently than men.

As thoracic outlet syndrome becomes more widely studied and better understood, there are some general observations that seem to be applicable. These include:

• Mechanical issues - TOS is basically a problem of space availability due either to congenital anomalies or to injury or trauma which may cause chronic spasm.

• Neurogenic issues

  • 98% of cases are neurogenic
  • 15% may have an arterial component to the problem but TOS is rarely solely arterial in nature
  • 1.5% of patients with TOS have pure venous compression

• Structural anomalies cause most of the problems but only a few of these compromise circulation, thus circulatory tests for diagnosis may be misleading. Muscle spasm is an important factor in the intensity of the pain.

• An accurate diagnosis is based totally on the clinical picture and may require the participation of a team of professionals, (e.g., physicians, physical therapists) to arrive at an accurate diagnosis.