The contribution of a spinal mechanism in developing peripheral myoclonus: a case report.

Focal myoclonus of peripheral origin, i.e., peripheral myoclonus (PM), is a rare disorder. Although PM always accompanies a lesion in the peripheral nerve, supplying the affected muscles, its mechanism remains unclear. Here we present a patient with focal myoclonus of the thigh muscles following a traumatic lesion in the femoral nerve. Lumbar spinal anesthesia, as well as local anesthetic block of the femoral nerve, completely abolished the patient's myoclonus temporarily. This movement was remarkably diminished after a surgical exploration of the wound with the removal of fibrous tissue beneath the scar and liberation of the femoral nerve. This case suggests the contribution of a spinal relay mechanism in the development of PM, in addition to the contribution of a nerve lesion.