In the authors’ experience, unambiguous instances of thoracic outlet syndrome are not common. This has also been the experience of Wilbourn, whose review of this subject is recommended. One should be skeptical of the diagnosis unless the clinical and EMG features enumerated above are present. Common mistakes are to confuse the thoracic outlet syndrome with carpal tunnel syndrome, ulnar neuropathy or entrapment at the elbow, or cervical radiculopathy caused by arthritis or disc disease. Brachial neuritis may have a similar presentation. Imaging studies and careful nerve conduction and EMG studies may be necessary to exclude all of these disorders.
Treatment of the Thoracic Outlet Syndrome
A conservative approach is advisable. If the main symptoms are pain and paresthesia, Leffert suggests the use of local heat, analgesics, muscle relaxants, and an assiduous program of special exercises to strengthen the shoulder muscles. A full range of neck motions is then practiced. On such a regimen, some patients experience a relief of symptoms after 2 to 3 weeks. Instruction by a qualified physical therapist is invaluable.
Only if pain is severe and persistent and is clearly associated with the vascular or neurogenic features of the syndrome is surgery indicated. The usual approach is through the supraclavicular space, with cutting of fibrous bands and excision of the rudimentary rib. In cases of venous or minor arterial forms of the syndrome, some thoracic surgeons favor the excision of a segment of the first rib through the axilla. Pain is often dramatically relieved, but the sensorimotor defects improve only slightly. Sectioning of the scalenus muscle is not endorsed because, as already noted, the role of muscle in causing thoracic outlet syndrome has been questioned.
Other Painful Conditions Originating in the Neck, Brachial Plexus, and Shoulder
The brachial plexus is an important source of shoulder and arm pain. The main disorders are brachial neuritis and metastatic infiltration and radiation damage to the plexus. Chapter 44 discusses these disorders in detail.
Metastases to the cervical region of the spine are less common than to other parts of the vertebral column. They are, however, frequently painful and may cause root compression. Posterior extension of the tumor from the vertebral bodies or compression fractures may lead to the rapid development of quadriplegia.
The Pancoast tumor, usually a squamous cell carcinoma in the superior sulcus of the lung, may implicate the lower cervical and upper thoracic (T1 and T2) spinal nerves as they exit the spine. In these cases, a Horner syndrome, numbness of the inner side of the arm and hand, and weakness of all muscles of the hand and of the triceps muscle are combined with pain beneath the upper scapula and in the arm. The neurologic abnormalities may occur long before the tumor becomes visible radiographically.
Shoulder injuries (rotator cuff), subacromial or subdeltoid bursitis, periarthritis or capsulitis (frozen shoulder), tendonitis and arthritis, as has been mentioned, may develop in patients who are otherwise well, but these conditions also occur as complications of hemiplegia. The pain tends to be severe and extends toward the neck and down the arm into the hand. The dorsum of the hand may tingle without other signs of nerve involvement. Immobility of an arm following myocardial infarction may be associated with pain in the shoulder and arm and with vasomotor changes and secondary arthropathy of the hand joints (shoulder–hand syndrome); after a time, osteoporosis and atrophy of cutaneous and subcutaneous structures occur (Sudeck atrophy or Sudeck-Leriche syndrome). Similar changes may occur in the foot and leg, or all articular structures on the side of a hemiplegia, or in association with the painful lesions described in the first part of this chapter. The neurologist should know that these complications can be prevented by proper exercises and relieved by cooling of the affected limb.