Thoracic Outlet Syndrome Treated With Injecting Botulinum Toxin Into Middle Scalene Muscle and Pectoral Muscle Interfascial Planes: A Case Report.

Thoracic outlet compression syndrome is a complex syndrome of neurovascular compression at the superior thoracic aperture, thought to occur at 1 of 3 anatomical compartments: the interscalene triangle, the costoclavicular space, and the retropectoralis minor space. Injection into the middle interscalene muscle (ISM) and/or pectoralis muscle plane (PECS I and II) is gaining popularity because it provides significant symptomatic relief. A 44-year-old woman was diagnosed with thoracic outlet compression syndrome, with failed conservative therapy, including physical therapy. She refused surgical intervention. ISM and PECS I and II blocks with botulinum toxin type A were successful. In combination, PECS I/II and ISM injections can provide excellent symptomatic relief.