Analysis of the Vascular Configuration in 111 Hemifacial Spasm Patients ?Vascular common stem anomaly as a pathophysiological cause of hemifacial spasm?
One hundred and fifteen patients with hemifacial spasm were treated by micro vascular decompression surgery. 73 patients out of all patients were studied by the bilateral vertebral angiograms which were obtained by means of stereotactic straight antero?posterior roentgenograms with subtraction, and 38 patients were examined by unilateral vertebral angiograms of the affected side. 4 patients were not examined. According to detail study of these angiograms, of 111 patients, many variations of posterior inferior cerebellar artery ( PICA ) and anterior interior cerebellar artery ( AICA ) were found, The characteristic configuration of the vessels in posterior fossa of the hemifacial spasm patients were common stem anomaly ( common stem AICA and common stem PICA). The incidence of common stem artery which compressed the exit zone of facial nerve in right facial spasm patiens was 75.4 %, and 57.4 % in left facial spasm patients. The frequency of bilateraly common stem vessels which means high grade of anomaly was 45.0 % in right affected patients, and 27.3 % in left ill patients. In young female patients, the high incidence and high degree of common stem anomaly of the vessels was observed more frequently. These findings might suggest that the developmental anomaly of vessels in posterior fossa might be one of the factors of hemifacial spasm, and high frequency rate of hemifacial spasm in female
