title: Intracranial hypertension after surgery in patients with Chiari I malformation and normal or moderate increase in ventricular size.
abstract: OBJECTIVE
  To determine ICP changes in patients with Chiari type I malformation after posterior fossa reconstruction (PFR).
  
  
  METHODS
  We continuously monitored ICP before and after PFR in 12 patients with Chiari I malformation and with an Evans' Index below or equal to 0.33. Mean ICP (epidural sensor) and percentage of B waves were calculated 24 hours before surgery and during the first 7 days after surgery.
  
  
  RESULTS
  Mean ICP and percentage of B waves significantly increased after surgery despite a significant increase in the volume of the posterior fossa. The main finding revealed by control CT scans was compression of the quadrigeminal cistern with a reduction in size of the fourth ventricle. In six patients, a small transitory increase in supratentorial ventricular size was found.
  
  
  CONCLUSIONS
  A transitory increase in ICP is common after PFR. This increase could be explained by an initial reperfusion phenomena in the cerebellum that provokes a transitory deterioration in CSF dynamics. The effacement of the quadrigeminal cistern and the reduction in size of the fourth ventricle suggests this hypothesis.
authors.affiliation: Department of Neurosurgery, Vall d'Hebron University Hospitals, Barcelona, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Poca
authors.forename: J
authors.initials: J
authors.lastname: Sahuquillo
authors.forename: J
authors.initials: J
authors.lastname: Ibañez
authors.forename: S
authors.initials: S
authors.lastname: Amorós
authors.forename: F
authors.initials: F
authors.lastname: Arikan
authors.forename: E
authors.initials: E
authors.lastname: Rubio
mesh_terms: D000328:Adult; D001139:Arnold-Chiari Malformation / Q000601:surgery*; D003388:Cranial Fossa, Posterior / Q000473:pathology / Q000601:surgery*; D004388:Dura Mater / Q000637:transplantation; D005260:Female; D005500:Follow-Up Studies; D006261:Headache / Q000209:etiology; D006801:Humans; D019586:Intracranial Hypertension / Q000209:etiology*; D007427:Intracranial Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D011183:Postoperative Complications / Q000503:physiopathology*; D013595:Syringomyelia / Q000150:complications; D013997:Time Factors; D014184:Transplantation, Homologous