title: Chiari malformation in craniosynostosis.
abstract: BACKGROUND
  Chiari malformation (CM) is a frequent finding in multisutural and syndromic craniosynostosis, occurring in 70% of patients with Crouzon's syndrome, 75% with oxycephaly, 50% with Pfeiffer's syndrome and 100% with the Kleeblattschädel deformity. The pathogenesis of this condition and rationale for treatment are still controversial.
  
  
  CONCLUSIONS
  Since its first description in 1972, several factors have been cited to play a role in inducing CM. In the light of recent publications, the roles of premature fusion of cranial vault and cranial base sutures, of congenital anomalies of the cerebellum and brain stem, of raised intracranial pressure, of venous hypertension and of hydrocephalus are reviewed. Evaluation and management of CM are also discussed.
  
  
  CONCLUSIONS
  Chiari malformation appears to be an acquired and progressive condition that develops in the first months of life, because of a disproportion between hindbrain growth and an abnormally small posterior fossa, a consequence of the premature fusion of lambdoid and cranial base sutures. Venous hypertension caused by stenosis of the jugular foramen can also be present in these patients, resulting in intracranial hypertension and/or hydrocephalus. Careful MRI evaluation is recommended for the forms of craniosynostosis at a high risk of developing hindbrain herniation. The selection of posterior cranial vault expansion as the first surgical procedure is advocated. In selected cases, treatment of the posterior cranial deformity by occipital vault remodelling and treatment of the Chiari-like deformity by suboccipital decompression can be carried out using the same surgical procedure.
authors.affiliation: Department of Pediatric Neurosurgery, Santobono-Pausilipon Children's Hospital, Naples, Italy. giuseppe.cinalli@fastwebnet.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cinalli
authors.forename: Pietro
authors.initials: P
authors.lastname: Spennato
authors.forename: Christian
authors.initials: C
authors.lastname: Sainte-Rose
authors.forename: Eric
authors.initials: E
authors.lastname: Arnaud
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Aliberti
authors.forename: Francis
authors.initials: F
authors.lastname: Brunelle
authors.forename: Emilio
authors.initials: E
authors.lastname: Cianciulli
authors.forename: Dominique
authors.initials: D
authors.lastname: Renier
mesh_terms: D001139:Arnold-Chiari Malformation / Q000209:etiology* / Q000235:genetics / Q000266:history / Q000473:pathology; D003393:Cranial Sutures / Q000002:abnormalities* / Q000473:pathology / Q000503:physiopathology; D003398:Craniosynostoses / Q000150:complications* / Q000235:genetics / Q000266:history / Q000473:pathology; D018450:Disease Progression; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology / Q000235:genetics / Q000473:pathology; D006973:Hypertension; D019586:Intracranial Hypertension / Q000503:physiopathology