Anatomical abnormalities involved in hemifacial spasm patients.
| Anatomical abnormalities | n |
|---|---|
| Abnormal fullness of the cerebellar flocculus | 37 |
| Narrow posterior fossa | 9 |
| Offending vessels in the outer peripheral portion of the facial nerve with protrusion of abnormal bone | 3 |
| Complex vascular anomalies in the dorsal indentation of the facial nerve | 12 |
| Local thickening of arachnoid adhesions | 6 |
| Several other coexisting anatomical abnormalities | 3 |