title: Horizontal C-1 fractures in association with unstable distraction injuries of the craniocervical junction.
abstract: OBJECTIVE
  Horizontal fractures of the anterior arch of the atlas not associated with odontoid fractures have been regarded as stable fractures that can be simply treated with a cervical collar. The authors report that C-1 horizontal fractures also occur in association with severe distraction injuries of the craniocervical junction.
  
  
  METHODS
  The authors retrospectively reviewed imaging studies obtained in all surviving patients in whom unstable distraction injuries of the craniocervical junction were diagnosed and in whom surgery was performed at their institution between 1995 and 2009. All patients who also had a C-1 horizontal fracture as a component of their spinal injury were included in the study.
  
  
  RESULTS
  Of 47 patients with unstable craniocervical distraction injuries, 5 patients had a horizontal fracture through the anterior ring of C-1: 1 patient had a primarily C1-2 distractive injury whereas 4 others had a grossly unstable injury across the occipitoatlantal junction (occipitoatlantal dissociation).
  
  
  CONCLUSIONS
  The finding of a C-1 horizontal fracture does not always reflect a benign injury and its presence should heighten the concern of a more severe and unstable injury at the craniocervical junction.
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle, Washington, USA. mdvilela@u.washington.edu
authors.forename: Marcelo D
authors.initials: MD
authors.lastname: Vilela
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Bransford
authors.forename: Carlo
authors.initials: C
authors.lastname: Bellabarba
authors.forename: Richard G
authors.initials: RG
authors.lastname: Ellenbogen
mesh_terms: D000293:Adolescent; D000328:Adult; D001270:Cervical Atlas / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D011859:Radiography; D012189:Retrospective Studies; D016103:Spinal Fractures / Q000000981:diagnostic imaging* / Q000601:surgery; D013123:Spinal Fusion; D016896:Treatment Outcome