Ultrasonographic Assessment of Radial Neuropathy Caused by Traumatic Neuroma

A patient presented with wrist drop, hand paresthesia, and no apparent history of injury to the hand. Electrodiagnostic testing suggested a radial nerve lesion between the triceps brachialis and extensor digitorum communis with poor reinnervation. The radial nerve was traced by ultrasound, from the axilla to the forearm, and a small comet-shaped mass was identified over the nerve above the elbow joint line. Magnetic resonance imaging of the affected elbow similarly revealed a nodular lesion along the distribution of the radial nerve. The patient underwent surgical excision of the lesion; histopathologic examination revealed a traumatic neuroma. Anatomic information from high-resolution ultrasound can complement neurophysiologic findings with a high degree of accuracy. Because it is inexpensive, noninvasive and dynamic, ultrasound should always be performed as a preliminary screen in patients who present with features of neurologic lesions of the extremities.