522 - Thoracic Outlet Syndrome – Monitoring progress with Upper extremity functional index scores: A Case Series

Case Diagnosis: Thoracic Outlet Syndrome (TOS) is a lower trunk plexopathy due to vascular or neurogenic etiologies. In neurogenic TOS, compression of Brachial Plexus (BP) due to a shortened pectoral minor muscle (PMM) is secondary to overly protracted shoulders. PMM compression can be visualized with dynamic positioning on Neuromuscular Ultrasound (NMUS).

Case Description: Two patients from our PM&R MSK clinic presented with similar chief complaints of neck pain, with associated paresthesia and weakness on the ipsilateral side. Both physical exams were significant for positive for Adson & Roos. Patient #1 work up was significant for Wrist brachial index revealed evidence of digit amplitude reduction in Adson position, electromyography was unremarkable. Patient #2, right shoulder arthrogram, electromyography of right upper extremity, and cervical MRI were all negative. Additional, investigation for both patients revealed PMM bowing with provocative movements. At follow up appointment, both patient's were trialed on Botox injections within the PMM for relief of symptoms. A post treatment upper extremity functional index (UEFI) was obtained for both patients to track results from their respective procedures.

Discussions: It is pivotal to identify PMM compression of BP on NMUS with maneuvers because static testing for both Vascular and Neurogenic TOS etiologies will typically be negative. After diagnosis, it is important to evaluate all non-surgical options for treatment. To look forward functional scoring and re-evaluation with NMUS can be used to track progress objectively.

Conclusions: This patient’s TOS diagnosis required a novel approach using NMUS to identify PMM bowing that is causing BP compression. Tracking functional index scoring can allow practitioners to monitor progress.