Venous TOS

vTOS is due to the impingement of the subclavian vein with resulting thrombosis. Hughes7 describes this “effort thrombosis,” or Paget-Schroetter syndrome, as axillary-subclavian vein thrombosis associated with strenuous and repetitive activity of the upper extremities.8 These patients have been shown to have a correlation with a multitude of underlying aggravating factors, including trauma, repetitive motion, and (although rare), a history of hypercoagulability.1 Trauma to the subclavian vein results in damage to the intima musculature that perpetuates thrombus formation; it is usually seen in younger and more active patients with an association of reported repetitive trauma to the shoulder region. Patients present with an acute or chronic onset of unilateral upper extremity swelling with red-purple discoloration and pain. Some patients report a chronic feeling of heaviness in the extremity.7

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Diagnosis of vTOS is made by a combination of clinical presentation and noninvasive studies. A duplex ultrasound of the subclavian vein in both the resting position and with the arm abducted to 90° is used. Results suggestive of vTOS are Doppler waveforms of both the subclavian and axillary veins showing significant decrease in vein velocity.

Treatment of vTOS is subjective to the treating physician’s preference. Nonoperative management of vTOS involves thrombolytic therapy or heparinization, whereas surgical management with thrombectomy and simultaneous first rib resection is another possibility.9,10 Operative management—thoracic outlet decompression—should be performed in symptomatic patients.

Arterial TOS

aTOS is the most infrequently seen subtype of thoracic outlet syndrome and is hypothesized to be due to recurrent friction of the subclavian artery with resultant fibrosis and subsequent stenosis of the subclavian artery. Arterial stenosis, as well as poststenotic aneurysms, may result in arterial thrombosis that can present with symptoms of decreased blood flow to the extremity. Chronically, the patient may complain of claudication or pain of the extremity with activity that subsides with rest. If emboli form, break off, and travel distally, patients may present with subacute focal symptoms such as an individual digit with decreased pallor.11 The most dangerous presentation is in patients who acutely form a completely thrombosed subclavian artery, resulting in decreased blood flow to the upper extremity. Of those patients with congenital bony abnormalities, the highest correlation was with patients diagnosed with aTOS.

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Similar to evaluation of vTOS, patients are best evaluated with Doppler waveforms of the subclavian and axillary arteries. In contrast to the Doppler study results found in patients with vTOS, patients with aTOS show increased velocity with stenosis of the artery, and absent velocities in cases of complete occlusion. Patients with aTOS have increased correlation with bony abnormalities compared with those with vTOS; as a result, patients with suspected aTOS should also receive a chest radiograph. As in patients with vTOS, thoracic outlet decompression should be performed in symptomatic patients.

Surgical management of TOS

After conservative management for each subtype of TOS fails, surgical management should be considered. Surgical approaches include the transaxillary approach, the supraclavicular approach, and the combined approach.

The transaxillary approach decompresses TOS by resecting the first rib. The supraclavicular approach is performed with anterior and middle scalenectomies with or without first rib resection. Both have been reported to have success rates between 75% and 99%; to date, no randomized clinical trial have been done to compare the two.12 In the combined approach, anterior and middle scalenectomies are done via the supraclavicular approach, and a first rib resection is done via the transaxillary approach. It has been reported that the combined approach improves long-term results and decreases recurrence rates.13

Complications of surgical procedures in these cases include injury to major neurovascular structures, which can be avoided with careful manipulation of structures and proximal control; supraclavicular nerve palsy, resulting in sensory deficit; phrenic nerve palsy, resulting in respiratory compromise; arterial or venous injury, resulting in bleeding or hemothorax; and thoracic duct injury, resulting in a chylous effusion.

Virginia Bailey, BA, is a medical student at the McGovern Medical School of The University of Texas; Justin Cardenas, BS, is a medical student at Baylor College of Medicine; and Maura Holcomb, MD, is a practicing dermatologist in Houston. 


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