Propriospinal myoclonus due to cervical disc herniation. Case report.

Propriospinal myoclonus is a rare form of spinal myoclonus. In most cases the cause has remained unclear. Secondary propriospinal myoclonus has been described secondary to various disorders including trauma, tumor, and infection. Thus far, propriospinal myoclonus caused by cervical disc herniation has not been reported. In the present report, the authors describe the case of a 53-year-old man who presented with radicular symptoms of the right C-6 nerve root and myoclonic twitches predominantly affecting the abdominal muscles but spreading to adjacent muscles. The spread was triggered and enforced by certain movements. Magnetic resonance imaging studies revealed a C-6 nerve root compression at the C5-6 level on the right side but no cervical myelopathy. Electromyography studies confirmed the diagnosis of propriospinal myoclonus. After discectomy and cage-augmented fusion via an anterior approach, the myoclonic movement disorder gradually subsided. To the authors' knowledge, this is the first report on successful treatment of propriospinal myoclonus by spinal disc surgery.