Hemifacial Spasm Caused by Vertebral Artery Dolichoectasia

Purpose: To display the characteristic magnetic resonance imaging (MRI) abnormalities associated with hemifacial spasm caused by compression of the seventh cranial nerve by a dolichoectatic vertebral artery.

Design: Interventional case report.

Methods: Correlation of imaging and clinical findings.

Results: In a 36-year-old man with mild left hemifacial spasm, MRI showed an enlarged (dolichoectatic) vertebral artery that compressed the seventh cranial nerve at its exit from the caudal pons. Manifestations of hemifacial spasm were relieved with periocular botulinum toxin injections.

Conclusion: In hemifacial spasm, MRI may show compression of the ipsilateral seventh cranial nerve or other structural abnormalities. Relief of hemifacial spasm may occur with botulinum toxin injection or with neurosurgical intervention designed to relieve the compression.