title: The comparative morphometric study of the posterior cranial fossa : what is effective approaches to the treatment of Chiari malformation type 1?
abstract: OBJECTIVE
  The objective of this study was to investigate changes in the posterior cranial fossa in patients with symptomatic Chiari malformation type I (CMI) compared to a control group.
  
  
  METHODS
  We retrospectively reviewed clinical and radiological data from 12 symptomatic patients with CMI and 24 healthy control subjects. The structures of the brain and skull base were investigated using magnetic resonance imaging.
  
  
  RESULTS
  The length of the clivus had significantly decreased in the CMI group than in the control group (p=0.000). The angle between the clivus and the McRae line (p<0.024), as the angle between the supraocciput and the McRae line (p<0.021), and the angle between the tentorium and a line connecting the internal occipital protuberance to the opisthion (p<0.009) were significantly larger in the CMI group than in the control group. The mean vertical length of the cerebellar hemisphere (p<0.003) and the mean length of the coronal and sagittal superoinferior aspects of the cerebellum (p<0.05) were longer in the CMI group than in the control group, while the mean length of the axial anteroposterior aspect of the cerebellum (p<0.001) was significantly shorter in the CMI group relative to control subjects.
  
  
  CONCLUSIONS
  We elucidate the transformation of the posterior cranial fossa into the narrow funnel shape. The sufficient cephalocaudal extension of the craniectomy of the posterior cranial fossa has more decompression effect than other type extension of the craniectomy in CMI patients.
authors.affiliation: Department of Neurosurgery, Dongtan Sacred Heart Hospital, College of Medicine, Hallym University, Hwaseong, Korea.
authors.forename: Hyung Sik
authors.initials: HS
authors.lastname: Hwang
authors.affiliation: Department of Neurosurgery, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea.
authors.forename: Jae Gon
authors.initials: JG
authors.lastname: Moon
authors.affiliation: Department of Neurosurgery, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea.
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Kangdong Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea.
authors.forename: Sae-Moon
authors.initials: SM
authors.lastname: Oh
authors.affiliation: Department of Neurosurgery, Sacred Heart Hospital, College of Medicine, Hallym University, Anyang, Korea.
authors.forename: Joon-Ho
authors.initials: JH
authors.lastname: Song
authors.affiliation: Department of Neurosurgery, Soonchunhyang Unviersity Bucheon Hospital, Bucheon, Korea.
authors.forename: Je Hoon
authors.initials: JH
authors.lastname: Jeong
keywords: Congenital abnormality; Decompressive craniectomy; Embryology; Posterior cranial fossa; Type I Arnold-Chiari malformation