Hemifacial spasm: endoscopic vascular decompression.

Sixty patients with primitive hemifacial spasm were treated by means of a minimally invasive retrosigmoid approach in which endoscopic and microsurgical procedures were combined. Intraoperative endoscopic examination of the cerebellopontine angle showed that for 56 of the patients vessel-nerve conflict was the cause of hemifacial spasm. The most common offending vessel was the posterior inferior cerebellar artery (39 patients), next was the vertebral artery (23 patients), and last was the anterior inferior cerebellar artery (16 patients). Nineteen of the patients had multiple offending vascular loops. In one patient, another cause of hemifacial spasm was an epidermoid tumor of the cerebellopontine angle. For three patients, it was not possible to determine the exact cause of the facial disorder. Follow-up information was reviewed for 54 of 60 patients; the mean follow-up period was 14 months. Fifty of the patients were in the vessel-nerve conflict group. Forty of the 50 were free of symptoms, and four had marked improvement. The overall success rate was 88%, and there was minimal morbidity (no facial palsy, two cases of severe hearing loss).