title: In vitro experiment for verification of the tandem shunt valve system: a novel method for treating hydrocephalus by flexibly controlling cerebrospinal fluid flow and intracranial pressure.
abstract: OBJECTIVE
  The CSF shunt valve is a medical device whose main function is to regulate intracranial pressure and drain excess CSF. The authors have developed a new therapeutic method for treating hydrocephalus, namely the tandem shunt valve system, which has the potential of flexibly controlling the CSF flow rate and intracranial pressure in patients.
  
  
  METHODS
  The properties of the tandem system were verified by performing in vitro experiments. An in vitro system with a manometer was built to measure pressure and flow rates of water in open systems using the Codman Hakim Programmable Valve and the Strata adjustable pressure programmable valve. A single valve and 2 single shunt valves connected in series (the tandem shunt valve system) were connected to the manometer to check the final pressure.
  
  
  RESULTS
  Conventional single shunt valve systems require valve pressures to be set higher to slow down the CSF flow rate, which inevitably results in a higher final pressure. On the other hand, the tandem shunt valve system uses the combination of 2 valves to slow the CSF flow rate without increasing the final pressure.
  
  
  CONCLUSIONS
  The authors succeeded in experimentally demonstrating in vitro results of tandem systems and their effectiveness by applying a model to show that the valve with the higher pressure setting determined the final pressure of the entire system and the flow rate became slower than single shunt valve systems.
authors.affiliation: Department of Neurosurgery, Tokyo Women's Medical University, Tokyo, Japan. yaihara@nij.twmu.ac.jp
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Aihara
authors.forename: Ichiro
authors.initials: I
authors.lastname: Shoji
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Okada
mesh_terms: D000465:Algorithms; D002557:Cerebrospinal Fluid Shunts / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D006849:Hydrocephalus / Q000134:cerebrospinal fluid* / Q000503:physiopathology / Q000601:surgery*; D019585:Intracranial Hypotension / Q000601:surgery*; D007427:Intracranial Pressure; D008365:Manometry; D019635:Neurosurgical Procedures / Q000379:methods; D011312:Pressure