Compressive radial nerve palsy induced by military shooting training: clinical and electrophysiological study

Ten recruited soldiers developed acute left wrist drop and numbness on the back of the thumb after a three hour military shooting training. Neurological examination disclosed decreased muscle power (0-2/5) of left wrist dorsiflexion, hypalgesia and hypaesthesia on the radial side of the left hand, and diminished brachioradialis reflex. Electrophysiological studies showed prolonged distal latency, reduced amplitude and slowness of left radial nerve motor conduction velocity between the axilla and elbow. Electromyography (EMG) revealed fibrillation potentials at rest, polyphasic motor unit and an incomplete interference pattern at volition over the extensor digitorum communis and brachioradialis. Nine patients recovered completely clinically and electrophysiologically between nine and 12 weeks after the onset of the palsy. Sensation recovered faster than the weakness. One patient failed to recover after three months, possibly because of the longer duration of nerve compression. Longer nerve compression time and sustained, decreased muscle power with signs of active denervation in EMG are indicators of poor prognosis.