Microsurgical treatment of intractable hemifacial spasm.

Ten patients with intractable hemifacial spasm were treated by posterior fossa exploration and microsurgical technique. These patients have been followed 1 to 5 years. The spasmodic motor disorder was related to compression of the 7th nerve or its exit zone at the brain stem by a dolichoectatic anterior inferior cerebellar artery in eight patients and to kinking and ectasia of the basilar or vertebral artery in two patients. In five patients, there were prominent arachnoidal adhesions in the cerebellopontine angle, and an arachnoid cyst was a component of the lesion in another patient. Additional conditions associated with hemifacial spasm included geniculate neuralgia, facial paresis, vertigo, hearing loss, and trigeminal neuralgia. The surgical morbidity and postoperative results are discussed.