Electrophysiologic Features of Radial Neuropathy in Childhood and Adolescence

Background: We analyzed the clinical and electrophysiologic patterns of nerve injury in pediatric patients with radial neuropathy. Methods: This is a retrospective analysis of 19 children and adolescents with radial neuropathy. Results: The mean subject age was 12 years (range one month to 19 years), 56% were female, and 53% had traumatic etiologies. Weakness in the finger and wrist extensors was the prevailing complaint (82%). Predominant localization was at the posterior interosseous nerve (37%), followed by the radial nerve below the spiral groove (32%), the radial nerve at the spiral groove (26%), and the radial nerve above the spiral groove (5%). Extensor indicis proprius compound muscle action potential amplitude was reduced in 86% of cases when tested, with a median axon loss estimate of 78%. The radial sensory nerve action potential amplitude was reduced in 53% of all cases, and in 83% of cases affecting the main radial trunk with a median axon loss estimate of 100%. For neuropathy affecting the main radial trunk, there was a high correlation of extensor indicis proprius median axon loss estimate and radial sensory nerve action potential median axon loss estimate (r = 0.72, P = 0.02). Neurogenic changes were seen in the extensor indicis proprius, extensor digitorum communis, extensor carpi radialis, and brachioradialis in 88%, 94%, 60%, and 44% of cases, respectively. Pathophysiology was demyelinating in 10%, axonal in 58%, and mixed in 32%. Conclusions: In contrast to adults, where localization at the spiral groove predominates, radial neuropathy in children and adolescents is commonly localized at the posterior interosseous nerve or at the distal main radial trunk. Pediatric radial neuropathy is frequently of traumatic etiology and axonal pathophysiology.