[Neurogenic muscular hypertrophy. Association with abnormal electrophysiological activities].

Muscle hypertrophy in neurogenic disorders is an uncommon phenomenon which has been reported in various conditions: hereditary or acquired anterior horn cell diseases, essentially S1 radicular compressions, and polyneuritis generally of a demyelinating type. We report two cases of denervating disease with muscle hypertrophy. The first was an S1 radiculopathy, and the second a compression with ischemia of the spinal cord by herniation of the D11-D12 disc, and showing partial improvement after surgery. In both cases, electrophysiological examination of the hypertrophic muscles revealed abnormal activities identified as complex repetitive discharges. In the second case they were associated with a syndrome of continuous motor unit activity. Such activities are rare in peripheral nerve involvement. However they have quite often been recorded in cases of neurogenic muscle hypertrophy and may therefore be partly responsible for the development of the hypertrophy.