title: Preoperative assessment of hemifacial spasm by the coronal heavily T2-weighted MR cisternography.
abstract: BACKGROUND
  Microvascular decompression (MVD) has become a well-established surgical procedure for hemifacial spasm (HFS). Before surgery, it is essential to evaluate any possible deformity of the brainstem and establish the precise location of the offending vessels. In the present study of HFS patients we examined coronal sections taken by heavily T2-weighted MR cisternography in addition to routine axial sections, and assessed the usefulness of these images through comparison with intraoperative findings.
  
  
  METHODS
  Eighty patients with HFS underwent preoperative coronal heavily T2-weighted MR cisternography before microvascular decompression surgery. Three neurosurgeons examined the preoperative axial and coronal MR images and evaluated vessel invagination into the brainstem. The usefulness of coronal sections was assessed statistically by the Mann-Whitney U test.
  
  
  RESULTS
  Invagination of the offending vessel into the brainstem was observed in 24 cases (30.0%). In 19 patients, it was predicted preoperatively that compression of the flocculus and brainstem would be required in order to approach the offending vessels. Coronal MR cisternography was significantly more useful in cases with vessel invagination into the brainstem than in cases without invagination.
  
  
  CONCLUSIONS
  Coronal sections obtained by MR cisternography are able to demonstrate the severity of vessel invagination into the brainstem as well as revealing the presence of the offending vessel. This information is helpful for planning a suitable approach to the root exit zone.
authors.affiliation: Department of Neurosurgery, Saitama Medical University, 38 Morohongo, Moroyama-cho, Iruma, Saitama, 350-0495, Japan, m_johta@saitama-med.ac.jp.
authors.forename: Miki
authors.initials: M
authors.lastname: Ohta
authors.forename: Masahito
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Kenji
authors.initials: K
authors.lastname: Wakiya
authors.forename: Sachiko
authors.initials: S
authors.lastname: Takamizawa
authors.forename: Mamoru
authors.initials: M
authors.lastname: Niitsu
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Fujimaki
mesh_terms: D000328:Adult; D000368:Aged; D001933:Brain Stem / Q000098:blood supply / Q000473:pathology* / Q000601:surgery; D002536:Cerebral Arteries / Q000473:pathology; D003399:Craniotomy / Q000379:methods; D020220:Facial Nerve Injuries / Q000150:complications / Q000175:diagnosis*; D005260:Female; D005500:Follow-Up Studies; D019569:Hemifacial Spasm / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D061145:Microvascular Decompression Surgery; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000150:complications / Q000175:diagnosis*; D011300:Preoperative Care / Q000379:methods*