title: Chiari type I malformation presenting as hemifacial spasm: case report.
abstract: OBJECTIVE
  We report on a patient with a Chiari I malformation presenting with right hemifacial spasm. Clinicians should consider the downward displacement of the hindbrain as a rare cause of hemifacial spasm in Chiari I malformation.
  
  
  METHODS
  An 18-year-old man was admitted with right hemifacial spasm. The results of the neurological examination were normal except for the facial spasm. Magnetic resonance imaging demonstrated a Chiari I malformation without syringomyelia. After surgery, the hemifacial spasm completely resolved.
  
  
  METHODS
  Posterior fossa decompression, C1 laminectomy, and duraplasty were performed.
  
  
  CONCLUSIONS
  The hemifacial spasm could be attributed to compression and/or traction of the facial nerve because of downward displacement of the hindbrain in Chiari I malformation. Compression and/or traction might create irritation of the facial nerve that causes hemifacial spasm. Resolution of the hemifacial spasm after posterior fossa decompression could explain the facial nerve irritation in Chiari I malformation. Clinicians should consider Chiari malformation as a cause of hemifacial spasm and posterior fossa decompression as a potential treatment.
authors.affiliation: Department of Neurosurgery, Social Security Ankara Education and Research Hospital, Ankara, Turkey. colpan@iit.edu
authors.forename: Mustafa Efkan
authors.initials: ME
authors.lastname: Colpan
authors.forename: Zeki
authors.initials: Z
authors.lastname: Sekerci
mesh_terms: D000293:Adolescent; D001139:Arnold-Chiari Malformation / Q000150:complications* / Q000601:surgery; D003388:Cranial Fossa, Posterior / Q000473:pathology; D019299:Decompression, Surgical / Q000379:methods; D005539:Foramen Magnum / Q000473:pathology; D019569:Hemifacial Spasm / Q000209:etiology* / Q000601:surgery; D006801:Humans; D007796:Laminectomy / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male