365 - Ballistic Injury of Radial, Median, and Ulnar Nerves

Case Diagnosis: Left radial, median and ulnar neuropathy

Case Description: We present a 36-year-old right-handed male with a gunshot wound causing a complex comminuted fracture of the left distal humerus, with immediate loss of strength and sensation in the entire forearm and hand. Imaging showed extensive ballistic fragments and gas presence. The radial nerve appeared intact during surgical exploration and was treated conservatively with hand therapy and wrist bracing. Hand intrinsic and flexor strength improved with time, but extensor compartment function did not. Electrodiagnostic evaluation 9 months post-injury for 0/5 wrist and finger strength, and radial forearm and hand sensory loss showed complete left axonal radial mononeuropathy with no reinnervation distal to the triceps, as well as evidence of prior partial axonal left median an ulnar mononeuropathy with completed reinnervation. He was ultimately treated with tendon transfer to improve hand function.

Discussions: Radial nerve injuries occur in about 10% of humeral shaft fractures, with 80% recovering spontaneously within 6 months, and can be treated with a “watch and wait” approach. However, when injury is due to a gunshot or other blast injury, prognosis is less favorable. Less than 25% of ballistic upper extremity nerve injuries show resolution within 12 months, and additional worse outcomes have been reported for presence of shrapnel. Shrapnel and ballistic foreign body removal, nerve exploration past the zone of direct ballistic path, neurolysis, and nerve grafting may improve outcomes, especially when performed within 3 months.

Conclusions: Prognosis for spontaneous improvement of ballistic related nerve injuries is poor, and exploration followed by early electrodiagnostic evaluation is recommended for prognostication, to help plan early intervention such as neurolysis or nerve grafting, and to assess for viability of tendon transfers when there are multiple nerve injuries.