title: Cervical myelopathy caused by pseudoarthrosis between the atlas and axis associated with diffuse idiopathic skeletal hyperostosis.
abstract: METHODS
  This is a report of a patient with severe cervical myelopathy due to pseudoarthrosis between the posterior tubercle of the atlas and the spinous process of the axis, associated with diffuse idiopathic skeletal hyperostosis. Radiographs of 170 patients with neck pain were reviewed to identify lesions involving abnormal contact between the atlas and axis.
  
  
  OBJECTIVE
  Based on an analysis of 170 radiographs, the prevalence of the reported condition was estimated.
  
  
  BACKGROUND
  A number of histologic studies on pseudoarthrosis involving the lumbar spine have been reported. In contrast, lesions between the posterior tubercle of the atlas and the spinous process of the axis have not been reported in association with cervical myelopathy.
  
  
  METHODS
  Clinical and pathologic features of a patient with pseudoarthrosis between the posterior tubercle of the atlas and the spinous process of the axis were investigated. Radiographs of 170 Japanese patients over 40 years old were examined, and abnormal contact between the atlas and axis was classified into two groups based on the degree of spinal hyperostosis.
  
  
  RESULTS
  Of 170 patients, 53 showed abnormal contact between the atlas and axis. The prevalence of abnormalities in the pronounced hyperostosis group (Forestier's stages II and III) was much higher than in the group with normal or slight hyperostosis. Two men had radiographic patterns showing osteophytes projecting into the spinal canal and associated with marked cervical myelopathy.
  
  
  CONCLUSIONS
  In the group with pronounced hyperostosis, pseudoarthrosis or a variant can cause serious problems in the upper cervical spine that should not be overlooked.
authors.affiliation: Department of Orthopaedic Surgery, Chiba University Hospital, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Goto
authors.forename: T
authors.initials: T
authors.lastname: Tanno
authors.forename: H
authors.initials: H
authors.lastname: Moriya
mesh_terms: D017677:Age Distribution; D001368:Axis, Cervical Vertebra / Q000000981:diagnostic imaging / Q000473:pathology*; D001270:Cervical Atlas / Q000000981:diagnostic imaging / Q000473:pathology*; D002574:Cervical Vertebrae; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood / Q000150:complications; D015576:Hyperostosis / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011542:Pseudarthrosis / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D013115:Spinal Canal / Q000473:pathology; D013128:Spinal Osteophytosis / Q000209:etiology*; D014057:Tomography, X-Ray Computed