Hemifacial spasm: electrophysiological findings and the therapeutic effect of facial nerve block.

Twenty patients with cryptogenic hemifacial spasm have been examined electrophysiologically and treated with blockade of the facial nerve with phenol injections after localization of the nerve by electrical stimulation. The electrophysiological findings suggested a central origin of the spasms. The phenol injections abolished the spasms, but they recurred in most patients after 6 to 12 months. A few patients appeared to get permanent relief after one or more phenol injections. We used phenol blockade of the facial nerve as our first therapeutic treatment of choice in patients with distressing hemifacial spasm because it is a safe, simple, and repeatable procedure.