title: Preoperative Three-Dimensional Diagnosis of Neurovascular Relationships at the Root Exit Zones During Microvascular Decompression for Hemifacial Spasm.
abstract: OBJECTIVE
  Hemifacial spasm occurs when a blood vessel compresses against an area near the root exit zone of the facial nerve. Developments in diagnostic neuroimaging have allowed three-dimensional (3D) observation of artery and nerve locations, an effective aid for treatment selection. However, an accurate interpretation of the 3D data remains challenging because imaging representations of complex small vessels are drowned out by noise. We used a noise elimination method to analyze artery and nerve locations and to determine their 3D relationship.
  
  
  METHODS
  Fifteen patients treated for hemifacial spasm were included. Images fused from 3 modalities of magnetic resonance imaging, 3D computed tomography, and angiography were used as source images. Using the images, models of the nerve and candidate vessels were created and shown in 3D to observe how the arteries were compressing the nerve and to identify the portions of the offending vessels that were closest to the nerve. These preoperative results were then compared with operative field observations during surgery. 3D models of the unaffected side were created and evaluated as controls.
  
  
  RESULTS
  We confirmed that these models were accurate reconstructions of the source images as the tubular nerve and artery cross-sections showed good alignment onto magnetic resonance imaging axial slice images. The preoperative diagnoses of the compression sites and offending arteries all matched intraoperative findings.
  
  
  CONCLUSIONS
  An accurate identification of the offending arteries and compression sites was possible, and this method is anticipated to offer effective means of preoperative simulation.
authors.affiliation: Department of Neurosurgery, Jichi Medical University, Tochigi, Japan. Electronic address: m01011ko@jichi.ac.jp.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ohtani
authors.affiliation: Department of Neurosurgery, Jichi Medical University, Tochigi, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Mashiko
authors.affiliation: Department of Neurosurgery, Jichi Medical University, Tochigi, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Oguro
authors.affiliation: Department of Neurosurgery, Aomori City Hospital, Aomori, Japan.
authors.forename: Atsuhito
authors.initials: A
authors.lastname: Takemura
authors.affiliation: Department of Neurosurgery, Mito Brain Heart Center, Ibaraki, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Hatayama
authors.affiliation: Department of Neurosurgery, Aomori Prefectural Central Hospital, Aomori, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Department of Neurosurgery, Jichi Medical University, Tochigi, Japan.
authors.forename: Eiju
authors.initials: E
authors.lastname: Watanabe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005154:Facial Nerve / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D019569:Hemifacial Spasm / Q000000981:diagnostic imaging* / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D061145:Microvascular Decompression Surgery / Q000379:methods*; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000209:etiology; D011300:Preoperative Care; D016896:Treatment Outcome
keywords: Hemifacial spasm; Microvascular decompression; Three-dimensional surgical simulation