title: The distance between the posterior communicating arteries and their relation to the endoscopic third ventriculostomy in adults: An anatomic study.
abstract: BACKGROUND
  The diencephalic leaf of the Liliequist's membrane is a continuous structure that should be perforated in the endoscopic third ventriculostomy. Its lateral borders are penetrated by the third cranial nerve and the posterior communicating arteries. The most important complication of endoscopic third ventriculostomy is the vascular injury, such as the posterior communicating artery. The purpose of this study is to measure the distance between posterior communicating arteries located below the third ventricle floor and anterior of the mammillary bodies.
  
  
  METHODS
  In this observational prospective study 20 fresh brains from cadavers were utilized to measure the distance between the posterior communicating arteries in April 2008 at the Death Check Unit of our Institution. A digital photograph of the posterior communicating arteries was taken and the distance between the arteries was measured. The measurement was analyzed using descriptive statistics.
  
  
  RESULTS
  In the descriptive analysis of the 20 specimens, the posterior communicating arteries distance was 9 to 18.9 mm, a mean of 12.5 mm, median of 12.2 mm, standard deviation of 2.3 mm.
  
  
  CONCLUSIONS
  The detailed knowledge of vascular structures involved in the endoscopic third ventriculostomy as to the posterior communicating arteries distance provides a safe lateral vascular border when performing such procedure.
authors: Department of Neurology, Division of Neurosurgery, Hospital das Clínicas, University of São Paulo, São Paulo, SP, Brazil.
authors: Alicia Del Carmen Becerra
authors: Adel C
authors: Romero
authors: Carlos Eduardo
authors: CE
authors: da Silva
authors: Paulo Henrique Pires
authors: PH
authors: de Aguiar