title: A simple and consistent technique for ventricular catheter insertion using a tripod.
abstract: OBJECTIVE
  For long-term preservation of ventriculo-peritoneal (VP) shunt function, it is essential to place the ventricular catheter tip above the foramen of Monro. But the free-hand technique for ventricular catheter passage is not consistent.
  
  
  METHODS
  Supposing that a convex of skull matches to a sphere, in which the foramen of Monro is the center, a perpendicular direction from the surface of the sphere to inside always directs toward the center. The authors identified the range of skull where corresponded to the sphere by magnetic resonance imaging assessment and utilized tripod to achieve exactly perpendicular insertion of ventricular catheter. And an optimal length of catheter insertion was investigated by navigation system.
  
  
  RESULTS
  The anterior-posterior range of the spherical portion was from coronal suture to 20mm anterior, and the lateral range of it was between 15 and 35mm lateral from sagittal suture. The optimal catheter length for insertion was between 55 and 58mm from the brain surface. Ideal placement of a ventricular catheter tip was achieved in more than 90% of cases (31/34) with this technique.
  
  
  CONCLUSIONS
  Tripod-guided ventricular catheter insertion is a simple and reliable method for VP shunt at any angle of head-rotation.
authors.affiliation: Department of Neurosurgery, Teikyo University Chiba Medical Center, 3426-3 Anesaki, Ichihara-city, Chiba-Prefecture 299-0111, Japan. merrityamada@hotmail.co.jp
authors.forename: Shoko Merrit
authors.initials: SM
authors.lastname: Yamada
authors.forename: So
authors.initials: S
authors.lastname: Yamada
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Goto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakaguchi
authors.forename: Mineko
authors.initials: M
authors.lastname: Murakami
authors.forename: Katsumi
authors.initials: K
authors.lastname: Hoya
authors.forename: Akira
authors.initials: A
authors.lastname: Matsuno
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000033:anatomy & histology; D001932:Brain Neoplasms / Q000150:complications / Q000601:surgery; D002404:Catheterization / Q000295:instrumentation* / Q000379:methods*; D002552:Cerebral Ventricles / Q000033:anatomy & histology / Q000601:surgery*; D002557:Cerebrospinal Fluid Shunts; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000601:surgery; D008223:Lymphoma / Q000150:complications / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D038361:Neuronavigation / Q000295:instrumentation; D015203:Reproducibility of Results; D025321:Surgery, Computer-Assisted; D016896:Treatment Outcome; D017287:Ventriculoperitoneal Shunt