Coil Embolization of VA-PICA Aneurysm Presenting with Hemifacial Spasm with Assistance of Abnormal Muscle Response Monitoring.

Objective: We report a rare case of symptomatic vertebral and posterior inferior cerebellar arteries (VA-PICA) aneurysm-caused ipsilateral hemifacial spasm (HFS) for which coil embolization of the aneurysm with the assistance of abnormal muscle response (AMR) monitoring was effective.

Case Presentation: A 62-year-old woman presented with left HFS. Magnetic resonance imaging showed a saccular aneurysm of the left VA-PICA which compressed the seventh cranial nerve at its root exit zone (REZ).