Kinked Again! From Congenital Brachial Plexus Palsy to Adult Neurogenic Thoracic Outlet Syndrome: A Case Report.

Neurogenic thoracic outlet syndrome is a chronic, focal lesion of the lower trunk of the brachial plexus or of the T1 and C8 anterior primary rami, often arising due to distortion of neural structures by a fibrous congenital band extending from a C7 transverse process or cervical rib. Accordingly, patients present with chronic weakness or atrophy of the hand, most prominently of the thenar eminence, which receives most innervation from the T1 root. We present clinical, electrophysiologic, and imaging findings in a case of neurogenic thoracic outlet syndrome presenting in an adult with a history most suggestive of congenital brachial plexus palsy, another pathology sharing the mechanism of nerve compression or injury within the supracostoclavicular space. The patient had new right thenar eminence atrophy and a lifelong history of medial forearm sensory deficit and she improved after first rib resection. The convergence of two disorders in the same patient arising in different phases of life illustrates how anatomic or structural variation in this space can predispose to lower brachial plexus injury.