title: Traumatic vertical atlantoaxial instability in a case of atlanto-occipital coalition.
abstract: METHODS
  This is a report of a woman with an atlanto-occipital coalition who experienced a traumatic vertical atlantoaxial facet dislocation and severe associated neurologic injury.
  
  
  OBJECTIVE
  To describe the radiographic and pathoanatomic characteristics of the injury process.
  
  
  BACKGROUND
  Severe injuries of the occipito-atlantoaxial complex are uncommon and only rarely are associated with patient survival. This is the first report of this particular injury.
  
  
  METHODS
  Plain radiography and tomography demonstrated the facet dislocation and instability of the injury. Surgical exploration for repair of the torn dura mater and bony arthrodesis demonstrated the gross pathoanatomy.
  
  
  RESULTS
  The patient's vertical atlantoaxial instability was stabilized, her dura mater reconstructed, and her necrologic status has improved to allow mobilization with a cane.
  
  
  CONCLUSIONS
  Vertical atlantoaxial instability has not been described previously. From the somewhat subtle radiographic findings, one might underestimate the severity of the neurologic damage. Aggressive work-up and management of this injury is suggested to avoid potential further necrologic sequelae.
authors.affiliation: Summa Health Systems Department of Orthopaedic Surgery, Section of Spinal Surgery, Akron, Ohio, USA.
authors.forename: B K
authors.initials: BK
authors.lastname: Weiner
authors.forename: R S
authors.initials: RS
authors.lastname: Brower
mesh_terms: D000063:Accidents, Traffic; D000328:Adult; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging / Q000293:injuries* / Q000473:pathology; D001368:Axis, Cervical Vertebra / Q000000981:diagnostic imaging; D001270:Cervical Atlas / Q000002:abnormalities / Q000000981:diagnostic imaging; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D007593:Joint Instability / Q000209:etiology; D011859:Radiography; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery