title: Hemifacial spasm caused by a contralateral vertebral artery: case report.
abstract: BACKGROUND
  Hemifacial spasm is usually caused by compression of the facial nerve by ipsilateral blood vessels. Compression of the facial nerve root exit zone by a contralateral tortuous vertebral artery is very rare.
  
  
  METHODS
  This 68-year-old woman presented with left-sided hemifacial spasm and was found to have compression of the left facial nerve by the tortuous vertebrobasilar artery, as revealed by magnetic resonance imaging and magnetic resonance angiography. Retromastoid craniectomy demonstrated compression of the left facial nerve root exit zone by the distal portion of the right vertebral artery. The vertebrobasilar junction and both vertebral arteries were moved laterally from the facial nerve and a muscle implant was interposed between the brainstem and the right vertebral artery.
  
  
  RESULTS
  The patient has remained free of hemifacial spasm for a follow-up period of 27 months.
  
  
  CONCLUSIONS
  Compression of the facial nerve by the contralateral tortuous vertebral artery may produce hemifacial spasm. A transposed large vessel can be secured by a sling technique or by interposing a soft implant between the brainstem and the vertebral artery.
authors.affiliation: Department of Neurosurgery, Russian Medical Academy of Postgraduate Education, Botkin Hospital, Moscow.
authors.forename: Y A
authors.initials: YA
authors.lastname: Grigoryan
authors.forename: M Z
authors.initials: MZ
authors.lastname: Goncharov
authors.forename: V V
authors.initials: VV
authors.lastname: Lazebny
mesh_terms: D000368:Aged; D005260:Female; D019569:Hemifacial Spasm / Q000209:etiology*; D006801:Humans; D019635:Neurosurgical Procedures / Q000379:methods; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000379:methods; D014711:Vertebral Artery / Q000473:pathology* / Q000601:surgery*