title: The incidence of Chiari malformation in nonsyndromic, single suture craniosynostosis.
abstract: BACKGROUND
  This study was designed to determine the incidence of Chiari malformation (CM) in nonsyndromic single suture craniosynostosis (N-SSSC).
  
  
  METHODS
  A retrospective analysis of brain magnetic resonance imaging (MRI) studies of children undergoing craniofacial surgery during 1 January, 2004-31 March, 2009 in Cleft Palate and Craniofacial Centre, Department of Plastic Surgery, Helsinki University Hospital, Helsinki, Finland, was conducted.
  
  
  CONCLUSIONS
  One hundred twenty-four N-SSSC patients were imaged using brain MRI. Of these 124 patients, seven patients were diagnosed with N-SSSC with an associated CM; the incidence CM in association with N-SSSC was thus 5.6%. The average age at the time of MRI was 37.7 months. All were males, except one. Only two types of synostosis were identified in this patient cohort: synostosis involving the sagittal suture in five cases and right coronal synostosis in two cases. The CM malformations were relatively large. The tonsillar herniation varied from 6 to 12 mm (median 9 mm). All these patients were asymptomatic of their CMs. None had operation designed directly to correct the CM.
  
  
  CONCLUSIONS
  As a conclusion, we state that the association of CM and N-SSSC is a relatively common finding, with an incidence of 5.6% in preoperative brain MRI. The significance of finding CM in preoperative brain MRI should be assessed individually in asymptomatic patients.
authors.affiliation: Department of Plastic Surgery, Helsinki University Hospital, Helsinki, Finland. junnu.leikola@hus.fi
authors.forename: Junnu
authors.initials: J
authors.lastname: Leikola
authors.forename: Virve
authors.initials: V
authors.lastname: Koljonen
authors.forename: Leena
authors.initials: L
authors.lastname: Valanne
authors.forename: Jyri
authors.initials: J
authors.lastname: Hukki
mesh_terms: D001139:Arnold-Chiari Malformation / Q000453:epidemiology* / Q000473:pathology; D001921:Brain / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003398:Craniosynostoses / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D004677:Encephalocele / Q000453:epidemiology / Q000473:pathology; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D012189:Retrospective Studies