Hemifacial Spasm.

Hemifacial spasm (HFS) is a peripheral movement disorder caused by direct or indirect compression or distortion of the root exit zone of the seventh cranial nerve, which is most commonly compressed by an arterial loop, but also may be compressed by a tumor, cyst, or aneurysm. All patients with HFS should undergo magnetic resonance imaging, with particular attention to the seventh cranial nerve. For patients with HFS who want treatment, there are three options. Oral medications, particularly anticonvulsants, may be useful, but the response rate is low and evidence is almost exclusively anecdotal. Local injection of botulinum toxin into the overactive muscles has a very high rate of success and virtually no serious side effects. Backed by controlled clinical trials, the authors consider it the treatment of choice. Microvascular surgical decompression has the advantage of being potentially curative, and obviates the need for chronic injections with botulinum toxin. However, surgery carries much greater risk than botulinum toxin and the spasm may recur. It is important that surgery is carried out by an experienced neurosurgeon to reduce the risk.