January 2018

Thoracic Outlet Syndrome

The evaluation of upper extremity dysesthesias may be challenging at times due to the multitude of conditions that can incite symptoms.  Thoracic outlet syndrome (TOS) is a well described condition that is often overlooked when evaluating the upper extremity. The term refers to compression of the neurovascular bundles as they exit the thoracic outlet region. This area is defined as the space between the supraclavicular fossa to the axilla that passes between the clavicle and the first rib. The sites of compression include the interscalene triangle, costoclavicular space and retropectoralis space. Anterior scalene tightness and cervical ribs are the most common structures inducing compression. Women between the ages of 20 and 40 are the population most commonly affected.

Compression of the brachial plexus is referred to as neurogenic TOS and compression of the subclavian vessels is referred to as vascular TOS. Neurogenic TOS compromises the majority of cases, over 90% of all cases. Symptoms include numbness, tingling, weakness and pain emanating from the shoulder region and radiating to the hand in a nonradicular distribution. Vascular TOS although much more rare, will present with more distinct symptoms and clinical findings such as severe swelling, cyanosis, pallor, coolness and even ischemia in severe arterial TOS. The diagnosis of TOS is often delayed as other more common conditions that produce similar symptoms are often focused on during initial evaluations. Electrodiagnostic studies are frequently utilized as a diagnostic tool for patients with extremity dysesthesias, but unfortunately there is not a clear result that strongly supports the diagnosis of TOS.

Several physical exam findings have been described that help support the diagnosis of TOS. For most patients repetitive overhead use of the arm often exacerbates the symptoms as the area of compression is increased. The following physical exam tests in conjunction with a thorough history my aide in the diagnosis of TOS.

Roos Test: The patient places both arms at 90 degrees abduction and elbow flexion. The patient then opens and closes the hands repeatedly for over one minute. This will illicit worsening symptoms and the patient may not be able to complete this due to early fatigue.

Wright’s Test: The patient brings the effected extremity in 90 degrees of abduction and elbow flexion with the neck rotated to the opposite extremity. The test is positive if the radial pulse is diminished and symptoms are reproduced.

Adson Test: With the radial artery palpated, the arm is brought into extension and slight abduction with the elbow fully extended.  The neck is then extended and rotated towards the effected extremity. If the radial pulse is diminished or symptoms are reproduced the test is positive.