Hemifacial spasm: treatment by microvascular decompression of the facial nerve at the pons.

Hemifacial spasm is a syndrome of intermittent and tonic unilateral facial muscular contraction; mild facial weakness on the same side is also frequently present. Hemifacial spasm can be differentiated clinically from habit spasms, blepharospasm, facial synkinesis following Bell's palsy, facial myokymia, and masticatory spasm. The syndrome of hemifacial spasm is caused by a variety of lesions; the common feature appears to be compression of the facial nerve at the pons. Diagnostic studies do not usually add significant information to that gained from the history and physical examination. The best current treatment (aside from removing an etiologic lesion such as a posterior fossa tumor in the small percentage of cases with such lesions) is microvascular decompression of the facial nerve at the pons through a retromastoid craniectomy. Of 30 patients treated in this manner, 28 have been satisfied with the results. On the most recent follow-up examination, 16 had no hemifacial spasm, nine had only slight periodic twitching about the eye, and three had occasional mild episodes of hemifacial spasm.