PR_054: Traumatic Nerve Injuries: Outcome Prediction Using Clinical and Electrodiagnostic Findings

Abstract

Objective: To determine clinical and electrodiagnostic parameters that are associated with traumatic nerve injury resolution. Design: A retrospective cohort of persons with traumatic peripheral nerve injuries who underwent electrodiagnostic testing at participating institutions was identified through chart review. Outcome information was then collected regarding return of strength and function through chart review of subsequent notes and, when possible, a follow-up patient evaluation with clinical and electrodiagnostic testing. Setting: Outpatient physical medicine and rehabilitation electrodiagnostic clinics. Participants: Persons with traumatic peripheral nerve injuries identified by electrodiagnostic testing. Interventions: Not applicable. Main Outcome Measures: Resolution of strength by manual muscle testing in key muscle groups related to the injured nerve. Self-reported resolution of function and self-reported pain were secondary outcomes. Results: There were a total of 18 patients with 19 separate nerve injuries. For those persons with a recordable compound muscle action potential (CMAP) over an involved muscle at the initial electromyography visit, 88% resolved to a muscle strength grade of 4 or greater. Of the patients who failed to resolve (manual muscle test grade ≤3), 90% did not have a recordable CMAP at the initial electromyography visit. Recruited motor units and initial strength testing were only somewhat predictive of resolution, and muscle fibrillation density was not predictive. Conclusions: The presence of an elicitable CMAP on initial electrodiagnostic testing can be used to predict muscle strength resolution. These findings should be further examined and confirmed in a larger scale investigation. Other meaningful outcomes such as pain, function, and quality of life should likewise be examined.