title: Tension pneumoventricle after resection of a fourth ventricle choroid plexus papilloma: An unusual postoperative complication.
abstract: BACKGROUND
  Pneumocephalus is defined as the presence of air within the intracranial vault. A common complication of head trauma and surgery, pneumocephalus is usually related to ventricular shunts, craniotomies, and surgery in the sitting position. Tension (symptomatic) pneumoventricle is a rare entity associated with significant clinical morbidity.
  
  
  METHODS
  We report an unusual case of a 15-year-old girl with tension pneumoventricle developed shortly after removal of a choroid plexus papilloma of the fourth ventricle by a midline suboccipital approach while in the sitting position.
  
  
  CONCLUSIONS
  The presence of a cerebrospinal fluid (CSF) diversion system that causes a decrease in intracranial pressure and the existence of a craniodural defect with or without an obvious CSF leak may be the cause of tension pneumoventricule. According to our present understanding, this is the first report of this peculiar complication of fourth ventricular surgery. We discuss clinical manifestations, surgical management, contributing factors, and mechanisms involved in the pathogenesis of tension pneumoventricle.
authors.affiliation: Department of Neurosurgery, Galeão Air Force Hospital, Rio de Janeiro, RJ, Brazil.
authors.forename: Mariangela B
authors.initials: MB
authors.lastname: Gonçalves
authors.forename: Cristian F
authors.initials: CF
authors.lastname: Nunes
authors.forename: José O
authors.initials: JO
authors.lastname: Melo
authors.forename: Rodrigo D
authors.initials: RD
authors.lastname: Guimarães
authors.forename: João
authors.initials: J
authors.lastname: Klescoski
authors.forename: José A
authors.initials: JA
authors.lastname: Landeiro