title: Survivors of occipitoatlantal dislocation injuries: imaging and clinical correlates.
abstract: OBJECTIVE
  Although rare, traumatic occipitoatlantal dislocation (OAD) injuries are associated with a high mortality rate. The authors evaluated the imaging and clinical factors that determined treatment and were predictive of outcomes, respectively, in survivors of this injury.
  
  
  METHODS
  The medical records and imaging studies obtained in 33 patients with OAD were reviewed retrospectively. Clinical factors that predicted outcomes, especially neurological injury at presentation and imaging findings, were evaluated. The most sensitive method for the diagnosis of OAD was the measurement of basion axial-basion dens interval on computed tomography (CT) scanning. Five patients with severe traumatic brain injuries (TBIs) were not treated and subsequently died. Of the 28 patients in whom treatment was performed, 23 underwent fusion and five were fitted with an external orthosis. Abnormal findings of the occipitoatlantal ligaments on magnetic resonance (MR) imaging, associated with no or questionable abnormalities on CT scanning, provided the rationale for nonoperative treatment. Of the 28 patients treated for their injuries, perioperative death occurred in five, three of whom had presented with severe neurological injuries. The mortality rate was highest in patients with a TBI at presentation. The mortality rate was lower in patients presenting with a spinal cord injury, but in this group there was a higher rate of persistent neurological deficits.
  
  
  CONCLUSIONS
  The spines in patients with CT-documented OAD are most likely unstable and need surgical fixation. In patients for whom CT findings are normal and MR imaging findings suggest marginal abnormalities, nonoperative treatment should be considered. The best predictors of outcome were severe brain or upper cervical injuries at initial presentation.
authors.affiliation: Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Horn
authors.forename: Iman
authors.initials: I
authors.lastname: Feiz-Erfan
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Lekovic
authors.forename: Curtis A
authors.initials: CA
authors.lastname: Dickman
authors.forename: Volker K H
authors.initials: VK
authors.lastname: Sonntag
authors.forename: Nicholas
authors.initials: N
authors.lastname: Theodore
mesh_terms: D000293:Adolescent; D000328:Adult; D001269:Atlanto-Occipital Joint / Q000293:injuries*; D001930:Brain Injuries / Q000150:complications* / Q000401:mortality; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D004204:Joint Dislocations / Q000150:complications* / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000209:etiology; D009989:Orthotic Devices; D011379:Prognosis; D013119:Spinal Cord Injuries / Q000150:complications*; D013123:Spinal Fusion / Q000401:mortality; D017741:Survivors; D014057:Tomography, X-Ray Computed