title: Does atlantoaxial dislocation influence the subaxial cervical spine?
abstract: BACKGROUND
  Previous studies have reported that the alignments of the occipital-cervical and subaxial spine were closely interrelated in asymptomatic individuals; however, none have focused on a population with atlantoaxial dislocation.
  
  
  METHODS
  From 2007 to 2011, 298 patients with atlantoaxial dislocation and atlas occipitalization were studied. Angles formed between Occiput-C2 and C2-C7 were measured. The relationship between the alignment of the occipital-cervical junction and the subaxial cervical spine was evaluated.
  
  
  RESULTS
  The range of values for the angles measured was as followed: the Occiput-C2 angles were -35.2° to 44.8°, and the C2-C7 angles were -17.4° to 77.8°. Statistically significant negative correlations were observed between the Occiput-C2 and C2-C7 angles.
  
  
  CONCLUSIONS
  Anterior dislocations of the atlas are associated with diminished lordosis or even kyphosis of the occipital-cervical junction, and result in compensatory hyperlordosis of the subaxial cervical spine, collectively presenting as a "swan neck" deformity. Atlantoaxial dislocation may influence the global cervical alignment.
authors.affiliation: Orthopaedic Department, Peking University Third Hospital, 49 North Garden Street, Haidian District, Beijing 100191, China.
authors.forename: Shenglin
authors.initials: S
authors.lastname: Wang
authors.forename: Peter G
authors.initials: PG
authors.lastname: Passias
authors.forename: Libin
authors.initials: L
authors.lastname: Cui
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.forename: Ming
authors.initials: M
authors.lastname: Yan
authors.forename: Haitao
authors.initials: H
authors.lastname: Zhou
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D055815:Young Adult