title: Surgical strategy for cervical dumbbell tumors based on a three-dimensional classification.
abstract: METHODS
  Forty-two patients with cervical dumbbell tumors were analyzed retrospectively using a new three-dimensional classification.
  
  
  OBJECTIVE
  To establish optimal surgical strategies, we considered shapes and three-dimensional locations of cervical dumbbell tumors based on diagnostic images and intraoperative findings.
  
  
  BACKGROUND
  Eden's classification for dumbbell tumors of the spine, long considered a "gold standard," no longer is sufficient to determine surgical strategy in view of recent advances in computed tomography and magnetic resonance imaging.
  
  
  METHODS
  Forty-two cervical dumbbell tumors were characterized according to transverse-section images (Toyama classification; nine types) and craniocaudal extent of intervertebral and transverse foraminal involvement (IF and TF staging; three stages each).
  
  
  RESULTS
  Type IIIa tumors, involving dura plus an intervertebral foramen, accounted for 50% of cases. A posterior approach was used in 35 patients; 7 others underwent a combined anterior and posterior approach. A posterior approach was used for all type IIa and IIIa tumors, and for some type IIIb (upper cervical), IV, and VI tumors; a combined posterior and anterior approach was used for type IIb and the remainder of type IV and VI. Reconstruction was performed using spinal instrumentation in 4 patients (9.5%). Resection was subtotal in 6 patients (14.3%) and total in 36 (85.7%).
  
  
  CONCLUSIONS
  Systematic, imaging-based three-dimensional characterization of shape and location of cervical dumbbell tumors is essential for planning optimal surgery. The classification used here fulfills this need.
authors.affiliation: Department of Orthopaedic Surgery, National Defense Medical College, Saitama, Japan. asayan@me.ndmc.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Asazuma
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Maruiwa
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Fujimura
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Hirabayashi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009442:Neurilemmoma / Q000601:surgery; D009455:Neurofibroma / Q000601:surgery; D012189:Retrospective Studies; D013125:Spinal Neoplasms / Q000145:classification / Q000601:surgery*; D014057:Tomography, X-Ray Computed