title: Occult spinal canal stenosis due to C-1 hypoplasia in children with Down syndrome.
abstract: OBJECTIVE
  Little has been published about subclinical spinal canal stenosis due to C-1 hypoplasia in patients with Down syndrome. In this paper the authors performed a matched comparison study with cross-sectional survey to investigate occult spinal canal stenosis due to C-1 hypoplasia in children with Down syndrome.
  
  
  METHODS
  A total of 102 children with Down syndrome ranging in age from 10 to 15 years were matched according to age and physique with 176 normal children. In all participants, the anteroposterior (AP) diameter of C-1 and the atlas-dens interval (ADI) were measured on plain lateral x-ray images of the cervical spine. The cross-sectional area of the atlas was also measured from a cross-sectional computed tomography image of C-1.
  
  
  RESULTS
  Eight children (6.7%) with Down syndrome developed atlantoaxial subluxation associated with myelopathy. The difference in the ADI between the patients and controls was not statistically significant. The average AP diameter of the atlas and the spinal canal area along the cross-section of the atlas were significantly smaller in children with Down syndrome than those in the control group.
  
  
  CONCLUSIONS
  Atlantoaxial instability and occult spinal canal stenosis due to C-1 hypoplasia in patients with Down syndrome may significantly increase the risk of myelopathy.
authors.affiliation: Department of Orthopaedic Surgery, Imakiire General Hospital Kibougaoka Hospital, Kagoshima, Japan. shunji@m.kufm.kagoshima-u.ac.jp
authors.forename: Shunji
authors.initials: S
authors.lastname: Matsunaga
authors.forename: Takanori
authors.initials: T
authors.lastname: Imakiire
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Koga
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ishidou
authors.forename: Hiromi
authors.initials: H
authors.lastname: Sasaki
authors.forename: Eiji
authors.initials: E
authors.lastname: Taketomi
authors.forename: Masaru
authors.initials: M
authors.lastname: Higo
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Setsuro
authors.initials: S
authors.lastname: Komiya
mesh_terms: D000293:Adolescent; D001268:Atlanto-Axial Joint / Q000002:abnormalities* / Q000000981:diagnostic imaging; D001270:Cervical Atlas / Q000002:abnormalities* / Q000000981:diagnostic imaging; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004314:Down Syndrome / Q000150:complications* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D013118:Spinal Cord Diseases / Q000150:complications / Q000453:epidemiology; D013130:Spinal Stenosis / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D013131:Spine / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed