Hemifacial spasm: treatment by posterior fossa surgery.

Nine cases of hemifacial spasm have been treated by posterior fossa exploration without mortality or significant morbidity. In only three was definite pathology found, but the hemifacial spasm was abolished in eight patients and markedly diminished in the remaining patient. The condition has reccurred in one patient. Microsurgical techniques make the operation safe and accurate. We suggest that this procedure is the best approach for hemifacial spasm requiring treatment. Where no definite pathology is found, the effectiveness of the procedure is probably due to fibrosis and hence mild trauma to the facial nerve induced by the sponge wrapped around the nerve.