In Vitro Hydrodynamic, Transient, and Overtime Performance of a Miniaturized Valve for Hydrocephalus

Helen N. Schwerdt, Usamma Amjad, Jennie Appel, Ali M. Elhadi, Ting Lei, Mark C. Preul, Ruth E. Bristol, Junseok Chae

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Reliable cerebrospinal fluid (CSF) draining methods are needed to treat hydrocephalus, a chronic debilitating brain disorder. Current shunt implant treatments are characterized by high failure rates that are to some extent attributed to their length and multiple components. The designed valve, made of hydrogel, steers away from such protracted schemes and intends to provide a direct substitute for faulty arachnoid granulations, the brain’s natural CSF draining valves, and restore CSF draining operations within the cranium. The valve relies on innate hydrogel swelling phenomena to strengthen reverse flow sealing at idle and negative pressures thereby alleviating common valve failure mechanisms. In vitro measurements display operation in range of natural CSF draining (cracking pressure, PT ~ 1–110 mmH2O and outflow hydraulic resistance, Rh ~ 24–152 mmH2O/mL/min), with negligible reverse flow leakage (flow, QO > −10 µL/min). Hydrodynamic measurements and over-time tests under physically relevant conditions further demonstrate the valve’s operationally-reproducible properties and strengthen its validity for use as a chronic implant.

Original languageEnglish (US)
Pages (from-to)603-615
Number of pages13
JournalAnnals of Biomedical Engineering
Issue number3
StatePublished - Mar 1 2015


  • Cerebrospinal fluid (CSF) draining
  • Check valve
  • Hydrocephalus
  • Hydrogel
  • Implantable microsystem
  • Intracranial pressure (ICP) regulation
  • Shunt

ASJC Scopus subject areas

  • Biomedical Engineering


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