title: Endoscopic third ventriculostomy in patients with a diminished prepontine interval.
abstract: OBJECTIVE
  Fenestration of the floor of the third ventricle is vital to the success of endoscopic third ventriculostomy (ETV) in treating patients with noncommunicating hydrocephalus. A generous prepontine interval (PPI) is generally accepted as one anatomical feature that may affect the safety and functionality of ETV. Whether a diminished PPI influences the safety or success of ETV, however, has not been adequately assessed.
  
  
  METHODS
  A review was conducted on the last 100 ETV procedures performed by the first author (M.M.S.). From archived preoperative MR imaging studies, the PPI was measured between the dorsum sellae and the basilar artery. For any patient with an interval of <or=1 mm, the technical and functional success of the procedure was recorded. Technical success was defined when a surgically created fenestration was accomplished without patient morbidity. Functional success was defined as the patient not needing any additional CSF diversionary procedure within 3 months after ETV.
  
  
  RESULTS
  In the entire cohort, the PPI ranged from 0 to 9.5 mm (mean 3.2 mm). There were 15 procedures performed in patients with a PPI of <or=1 mm. In all 15 procedures, a fenestration of the tuber cinereum was accomplished without vascular injury or patient morbidity. The ETV was successful in 11 patients (73.3%). All 4 failures occurred in children who had surgery during infancy (mean age 11 months).
  
  
  CONCLUSIONS
  Patients with an obliterated or reduced PPI can safely undergo ETV. The functional success rate appears equivalent to historical controls. Most failures in this series may be attributed to other patient characteristics, namely young age at the time of ETV.
authors.affiliation: Department of Neurological Surgery, Weill Cornell Medical College and Memorial Sloan-Kettering Cancer Center, New York 10021, USA. mmsouwei@med.cornell.edu
authors.forename: Mark M
authors.initials: MM
authors.lastname: Souweidane
authors.forename: Peter F
authors.initials: PF
authors.lastname: Morgenstern
authors.forename: Sungkwon
authors.initials: S
authors.lastname: Kang
authors.forename: Apostolos John
authors.initials: AJ
authors.lastname: Tsiouris
authors.forename: Jonathan
authors.initials: J
authors.lastname: Roth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004724:Endoscopy; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D007223:Infant; D008297:Male; D008875:Middle Aged; D011149:Pons; D011859:Radiography; D012189:Retrospective Studies; D012658:Sella Turcica; D013346:Subarachnoid Space; D020542:Third Ventricle / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D016896:Treatment Outcome; D014696:Ventriculostomy; D055815:Young Adult