title: Hydrocephalus and Chiari type I malformation.
abstract: BACKGROUND
  [corrected] Hydrocephalus has been related to Chiari type I malformation (CIM) for a long time. The pathogenesis of this association is complex and still debated.
  
  
  CONCLUSIONS
  A supratentorial hypertensive hydrocephalus may cause CIM, exerting pressure from above. Another pathogenetic hypothesis is based on the clinical and radiological data from patients affected by complex craniosynostosis, in which this association is more commonly observed as the consequence of a "cephalo-cranial disproportion" ultimately leading to a secondary hydrocephalus. In some cases, the concomitant presence of a stenosis of the jugular foramina would determine a condition of upward venous hypertension, resulting in the development of CIM and an associated hydrocephalus due to cerebellar parenchyma turgor.
  
  
  CONCLUSIONS
  The radiological association of ventricular enlargement and hindbrain herniation would be the result of heterogeneous pathogenetic mechanisms which would then require specific therapeutic approaches. In this context, the endoscopic third ventricle-cisternostomy is gaining an increasing interest because of its more physiologic correction of the altered CSF dynamics and its minor interference on the developmental processes responsible for the association of hydrocephalus and CIM.
authors.affiliation: Pediatric Neurosurgery, Catholic University Medical School, Policlinic A. Gemelli, Largo Agostino Gemelli, 8, 00168 Rome, Italy.
authors.forename: Concezio
authors.initials: C
authors.lastname: Di Rocco
authors.forename: Paolo
authors.initials: P
authors.lastname: Frassanito
authors.forename: Luca
authors.initials: L
authors.lastname: Massimi
authors.forename: Simone
authors.initials: S
authors.lastname: Peraio
mesh_terms: D001139:Arnold-Chiari Malformation / Q000150:complications* / Q000175:diagnosis; D003388:Cranial Fossa, Posterior / Q000196:embryology / Q000473:pathology; D006801:Humans; D006849:Hydrocephalus / Q000150:complications* / Q000175:diagnosis; D008279:Magnetic Resonance Imaging