Indications for surgical decompression are controversial. They include symptomatic patients who have vascular (arterial or venous) TOS and are not at high risk for surgery, patients with true neurologic TOS and acute progressive neurologic weakness or disabling pain,55 and patients who have disputed neurologic TOS and have failed conservative management—keeping in mind that high recurrence rates and iatrogenic brachial plexopathy have been reported in this population.56 In general, surgical procedures are aimed at reducing soft-tissue compression (scalene release or neurolysis) or bony compression (cervical or first thoracic rib excision). Three surgical approaches (transaxillary, supraclavicular, infraclavicular) are commonly used for decompression, and surgeons choose one over another depending on the anatomical abnormality causing the compression. The transaxillary approach requires limited dissection but still allows for adequate visualization of the rib during resection.57 In this approach, a transverse incision along the inferior border of the axilla extends from the pectoralis major to the latissimus dorsi. After dissection of the axillary vessels and the first thoracic nerve root, the first rib is identified and can be removed, when indicated. In contrast, the supraclavicular approach provides a wide exposure, and the site of compression is directly visualized, allowing for arterial reconstruction.58 Through this approach, the anterior and middle scalene muscles can be resected, and neurolysis of the brachial plexus can be performed. Last, the infraclavicular approach allows for exposure of the central veins through extension of the incision medially, which allows for venous reconstruction. Some patients with neurogenic or arterial TOS present with symptoms of sympathetic overactivity, in which case cervical sympathectomy can be used with decompression.
Outcomes of surgical decompression for TOS depend on the clinical type but are generally good. For instance, in cases of disputed neurogenic TOS, symptom resolution after decompression is reportedly between 80% and 90%.59 However, major depression, work-related injuries,60 and diffuse preoperative arm symptoms61 all influence long-term results. In true neurogenic TOS, postoperative pain relief is often substantial, though recovery of strength can be slow because of the axonal injury.55 In arterial TOS, outcomes are influenced by time to surgical intervention, with early surgery demonstrating better outcomes than later surgery.62 In one study, Cormier and colleagues14 evaluated 47 patients who underwent correction of subclavian-axillary artery compression; 91% were asymptomatic a mean of 5.7 months after decompression. Last, outcomes of successful thrombolysis and decompression for venous TOS demonstrated patency rates higher than 95% at 5-year follow-up.54,63
Conclusions
TOS is a spectrum of disorders caused by compression of the brachial plexus, subclavian artery, or subclavian vein. Early recognition of TOS is imperative, as diagnostic or treatment delays may be associated with significant morbidity. Clinical examination alone is often inadequate for determining the compression site and the structure causing compression. CTA and MRI performed in association with postural maneuvers may demonstrate dynamic compression of the neurovascular structures in the thoracic outlet. These imaging modalities reliably identify the structures causing compression and can be crucial for effective management.
