Correlation of Ultrasound and Electrodiagnostic Evaluation in Ballistic Peripheral Nerve Injuries.

Background: Evaluation and management of ballistic peripheral nerve injuries remain controversial, and recent series have suggested higher rates of nerve discontinuity than previously appreciated. Ultrasound (US) may aid clinicians in the management of ballistic injuries. The goal of this study was to compare US findings to electrodiagnostic and intraoperative findings to assess its accuracy in ballistic injuries. Methods: We conducted a retrospective review of patients with the following criteria: (1) ballistic injury to the upper or lower extremity with suspected mixed or motor peripheral nerve injury; (2) underwent electrodiagnostic studies (EDX) and peripheral nerve ultrasound. US findings were categorized as normal, enlarged, neuroma-in-continuity, partial transection, or complete transection. EDX were reviewed for abnormalities in compound motor action potential amplitudes. Results: Sixteen patients met our inclusion criteria, of whom 14 had US abnormalities: 8 neuromas-in-continuity, 2 complete transections/discontinuity, 1 partial transection, 2 enlargements, and 1 hypoechoic/fascicular irregularity. US detected 14 of 16 neurapraxic, axonotmetic, or neurotmetic peripheral nerve injuries after ballistic trauma. US had 88% sensitivity, with 0 false positives and 2 false negatives (negative on ultrasound, positive on electrodiagnostic testing) compared with electrodiagnostic testing. Conclusions: Our findings suggest that US is an accurate way to evaluate peripheral nerve injuries after ballistic trauma. US may play a role in early diagnostics, especially when EDX are of little value. Future work should focus on the accuracy of early US in ballistic injuries and determining the effects of US and EDX at varying time intervals.