A. McDonald, DM, FRCS(ED), H. De Paz, DM, FRCS(ED)
Department of Surgery, UWI, Jamaica, WI
Abstract
A case of TOS treated at the University Hospital of the West Indies, Jamaica, is presented and the diagnosis and management of TOS discussed.
Introduction
The thoracic outlet Syndrome (TOS) presents with neurological and vascular symptoms and signs in the neck and upper limb. The incidence of the neurological case of TOS is one per million (Hawkes 1986). In Jamaica at least two surgical decompressions should be done yearly. The fact that this is not so suggests that the condition is often missed.
Case Report
A 15 year-old female presented with a long history of a painful swelling on the left side of her neck along with cramps and numbness in the left upper limb. On physical examination there was a 2cm bony swelling in the left supraclavicular fossa. The left radial pulse was weaker than the right. The small muscles of the left hand were wasted and there was diminished sensibility to fine touch over the outer aspect of the left arm. Chest radiographs showed a left cervical rib and arteriography demonstrated subclavian arterial stenosis and post stenotic dilatation anterior to the tip of the cervical rib (Fig 1).
TOS was diagnosed and the transaxillary approach was used to resect the first thoracic rib, cervical rib and scalenus anticus on the affected side. Mild stenosis of subclavian artery did not require resection. The pleural cavity was inadvertently entered and a thoracostomy tube was inserted.
After operation the left radial pulse was normal and equal to the right in volume. Recovery was uneventful and the patient was discharged one week after surgery. At three months follow-up she had complete resolution of pain and cramps and normal sensation in the left upper limb.
Discussion
A vast number of conditions may result in pain in the neck and upper limb. These include nerve entrapment syndromes, cervical disc herniation, cervical tumours, Raynaud’s disease, neuropathies, Pancoast tumour and TOS. Arriving at the correct diagnosis involves a proper clinical assessment and investigations as well as an awareness of the various pathological processes involved. TOS is seldom diagnosed in Jamaica probably due to a lack of awareness of it’s existence. It is caused by compression of the neurovascular bundle in the thoracic outlet. Structures that produce compression include scalenus anticus, scalenus medius, first rib, clavicle and pectoralis minor (Huffman 1986; Nichols 1986). Compression is also associated with musculoskeletal and vascular anomalies. Cervical rib may be attached to first rib by a fibrous band (Wood 1988). They occur in 0.2-1 percent of the population.
TOS most commonly presents with brachial plexus compression manifested by pain, paraesthesia, numbness, muscle weakness, muscular atrophy and motor incoordination of the hand. Venous compression usually presents with subclavian or axillary vein thrombosis. Arterial compression usually results in diminution or abolition of the radial pulse on the affected side or a fall in blood pressure on abduction of the shoulder (Selke and Kelly, 1988). Other signs of arterial compression such as thrill, bruit, temperature change, claudication, ulceration and gangrene may also occur.
Careful evaluation of patients with neck and upper limb pain is essential if TOS is not to be missed. A careful history and physical examination is essential. A number of clinical tests are useful in arriving at a diagnosis. In Roos’ test the shoulders are abducted 90 degrees and the patient opens and closes the hand slowly for three minutes. Early fatigability, gradual onset of numbness and tingling, and subsequent ischaemic type pain in the hand constitute a positive test. Wood et al (1988) found this test to be positive in 64 percent of cases. Numbness and tingling radiating down the arm in response to thumb pressure on the brachial plexus in the supraclavicular fossa constitute a positive Spurling’s test. In the modified Adson’s test the patient turns the chin to the opposite side. This results in neurovascular compression in cases of TOS. Morley’s sign is the presence of tenderness over the first rib in the supraclavicular fossa. Hawkes (1986) found this to be a very reliable sign.
Radiographs of the cervical spine, shoulder and chest should be obtained. The possibility of myocardial ischaemia and reflux oesophagitis must be bourne in mind and the relevant investigation done if these are suspected. Myelography, computerized tomography, electromyography and conduction studies are useful to detect fibrous bands and nerve compression (Urchel and Razzuck, 1986; Riddel and Smith, 1986). Vascular compression may be demonstrated by angiography.
The initial management of these patients consists of physiotheraphy and nerve stimulation. Surgery is reserved for patients who do not respond to these measures. The cornerstone of surgical decompression is first rib resection. Scalenectomy and excision of fibrous bands is sometimes added (Thomas et al, 1983). Resection of a stenosed segment of the subclavian artery is indicated only if it persists following decompression.
The surgical approaches are numerous and depends on the preference of the surgeon. They include supraclavicular, infraclavicular, parascapular and transaxillary routes. The transaxillary method is popular as it gives good access and the scar is inconspicuous (Durham and McIntyre, 1985).
The results of surgery are good with 79-95 percent of patients symptom free (Roos, 1976). Persistence of symptoms is usually due to incomplete first rib resection for which re-operation is required.
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