Monitoring

During follow-up for conservative treatment and recovery from surgery, it is important to assess patient pain and neurogenic symptoms, as well as functional disability and its impact on work, school, recreation, and daily activities. This can be best quantified by evaluating changes in one or more patient-reported survey instruments, such as the QuickDASH score, compared with pretreatment measures.[1] The Derkash score is another commonly used measure to assess outcomes following surgical treatment, with patient-rated results described as “excellent” (no or minimal pain, easy return to professional and leisure activities, relief of almost all major symptoms with only some mild residual symptoms that do not significantly limit enjoyment of life); “good” (intermittent pain well-tolerated, possible to return to professional and leisure activities, relief of most major symptoms with some mild residual symptoms that do not significantly limit enjoyment of life); “fair” (intermittent or permanent pain not well-tolerated, difficult or no return to professional and leisure activities, partial relief of some symptoms while other major symptoms persist); and “poor” (symptoms not improved or aggravated after surgery, difficult or no return to professional and leisure activities, not enough relief in symptoms to have made the operation worthwhile).[211][212]​​

Neurogenic thoracic outlet syndrome (TOS) can recur after conservative treatment with physical therapy or after operative treatment. Following surgery, the principal causes of recurrent neurogenic TOS include a retained or unresected remnant of the first rib (particularly the posterior rib), reattachment of residual scalene muscles to exert pressure on the brachial plexus, and fibrous scar tissue formation around the brachial plexus nerves.[154][192][193][194][195][196]​​​​​​​[197][198]​​​​ Symptoms can recur from 3 months to 10 years after surgical intervention; however, in most instances, recurrence is observed within 1-2 years after operation and may be precipitated by a secondary injury. Conservative management is the preferred initial step in treatment but reoperative options are often feasible and fruitful. Patients should be advised to monitor for symptoms of recurrent compression of thoracic outlet neurovascular structures.

Patients with venous TOS that are treated without surgery, using long-term anticoagulation alone, are subject to persistent or recurrent axillary-subclavian vein thrombosis, with approximately 60% to 70% having arm swelling symptoms and post-thrombotic syndrome.[35][170]​​​​ The incidence of arm swelling is approximately 30% for those who had decompression surgery, but with a long chronic venous occlusion that precluded vein bypass reconstruction.[156][172]​​​​ The incidence of arm swelling is approximately 5% for patients that have had surgical treatment for venous TOS with decompression and a patent axillary-subclavian vein (or bypass), but these patients can still develop recurrent subclavian vein stenosis or thrombosis during follow-up.[52][91][113]​​​​​​[162][163][171][172][202][213][214]​​​​​​​[215]​​​​ This may be due to unresolved residual venous stenosis despite venous decompression or progressive vein wall scarring after a previous vein repair. Retention of an anterior remnant of the first rib is also a prominent and preventable cause of persistent vein compression. Venography and secondary endovascular interventions are often successful, including placement of venous stents if there has been adequate costoclavicular decompression.[166][167]​​ Reoperative options may also be feasible for recurrent venous TOS.[204] Patients should be educated regarding signs and symptoms of recurrence, so that they seek immediate evaluation in the unexpected event of recurrence.

Patients that have had treatment for arterial TOS may have persistent symptoms due to ischemic tissue damage from the time of initial treatment, or unresolved distal arterial obstruction. Following surgical treatment, recurrent arterial thrombosis and ischemia can occur during follow-up despite satisfactory decompression and arterial reconstruction, due to scarring and arterial wall thickening over time. Patients should be informed regarding the signs and symptoms of arterial ischemia, so that they seek immediate evaluation in the unexpected event of recurrence.

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