title: Asymmetric laterality of Chiari type I malformation in patients with non-syndromic single-suture craniosynostosis.
abstract: BACKGROUND
  Chiari type I malformation is a frequent incidental finding commonly associated with craniosynostosis. However, there seems to be a paucity of literature concerning the asymmetry of tonsillar herniation in patients with non-syndromic single-suture craniosynostosis.
  
  
  METHODS
  To study the asymmetry in this cohort, measurements of the right and left tonsils were made from sagittal images from both pre-operative and post-operative images from 11 patients with non-syndromic single-suture craniosynostosis.
  
  
  RESULTS
  Pre-operatively, the mean difference between the caudal descent of all tonsils ranged from 0 to 7 mm, with a mean difference between sides of 2.45 mm. In three cases, cerebellar tonsils were symmetrically herniated. Post-operatively, the mean difference between caudal descent of all tonsils ranged from 0 to 4 mm, with a mean difference between sides of 1.45 mm. Four were symmetrically herniated. In patients with non-syndromic single-suture craniosynostosis, the tonsillar herniation is asymmetric in the majority of cases.
  
  
  CONCLUSIONS
  Asymmetry of cerebellar tonsil herniation is a frequent finding in this cohort. The right tonsil is more inferiorly located in majority of cases, with predominance to the synostotic suture side in asymmetric craniosynostosis cases.
authors.affiliation: Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Karppinen
authors.forename: V
authors.initials: V
authors.lastname: Koljonen
authors.forename: L
authors.initials: L
authors.lastname: Valanne
authors.forename: J
authors.initials: J
authors.lastname: Leikola
mesh_terms: D001139:Arnold-Chiari Malformation / Q000150:complications / Q000473:pathology* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D003398:Craniosynostoses / Q000150:complications / Q000473:pathology* / Q000601:surgery; D004677:Encephalocele / Q000150:complications / Q000473:pathology*; D007839:Functional Laterality / Q000502:physiology; D006547:Hernia / Q000150:complications; D006801:Humans; D007223:Infant; D059906:Neuroimaging / Q000379:methods; D019635:Neurosurgical Procedures / Q000379:methods; D014066:Palatine Tonsil; D013537:Sutures; D016896:Treatment Outcome