Microvascular decompression for the treatment of hemifacial spasm. Retrospective study of a consecutive series of 75 operated patients--electrophysiologic and anatomical surgical analysis.

The authors report the results of a series of 75 patients operated on for hemifacial spasm by the same surgeon between October 1981 and January 1997. Microsurgical vascular decompression was performed through a retromastoid approach in contralateral position. The conflicting vessel was identified as the posterior inferior cerebellar artery in 41.3% of the cases, the anterior inferior artery in 38.6%, and the vertebrobasilar complex in 18.7%. Follow-up varied from 1 month to 13 years (with a mean duration of 5 years and 2 months). The outcome was excellent (total improvement) in 57 cases, good (> 75% improvement) in 11 cases, fair (< 75%) in 4 cases and poor in 3 cases. Neurological complications included deafness or hearing loss in 3 cases (2 occurred in the absence of intraoperative monitoring and the other during the first part of the series) and facial paralysis in 1 case. Brainstem auditory evoked potential (BAEP) intraoperative monitoring should be performed to avoid postoperative auditory complications; a marked auditory loss was observed in only 1.6% of the 60 patients of our series who underwent BAEP intraoperative monitoring.