Simulation of Existing and Future Electromechanical Shunt Valves in Combination with a Model for Brain Fluid Dynamics
Several models are available to simulate raised intracranial pressure (ICP) in hydrocephalus. However, the hydrodynamic effect of an implanted shunt has seldom been examined. In this study, the simple model of Ursino and Lodi is extended to include (1) the effect of a typical ball-in-cone valve, (2) the effect of the size of the diameter of the connecting tube from valve to abdomen, and (3) the concept of a controlled electromechanical shunt valve in overall cerebrospinal fluid dynamics.
By means of simulation, it is shown how a shunt can lower ICP. Simulation results indicate that P and B waves still exist but at a lower ICP level and that, due to the exponential pressure-volume curve, their amplitude is also considerably lowered. A waves only develop if the valve is partially blocked. The resulting ICP is above the opening pressure of the valve, depending on the drain and resistance of the shunt.
The concept of a new electromechanical shunt was more successful than the traditional mechanical valves in keeping ICP at a desired level. The influence of the patient’s movements or coughing on ICP as well as the body position affecting the reference ICP, which can be measured, has not yet been modeled and should be addressed in future using suitable algorithms.
KeywordsHydrocephalus Shunt Mechatronic/electromechanical valve Model A waves B waves
The authors thank the German Federal Ministry of Science and Education (BMBF) for financial support of the BMBF project “iShunt”.
Conflicts of interest statement Dr. M. Kiefer has received financial support in the past for activities other than this research, from Raumedic AG, Helmbrecht, Germany. All other authors declare that they have no conflict of interest.
- 1.Aschoff A (1994) In-vitro-Testung von Hydrocephalus-Ventilen. Professorial dissertation, Heidelberg University, Heidelberg, pp 86–179Google Scholar
- 8.Krause I, Jetzki S, Rehbaum H, Linke S, Kiefer M, Walter M, Leonhardt S (2009) Dynamic bench testing of shunt valves. In: Hydrocephalus. Baltimore, p 98Google Scholar
- 9.Kunze G, Göhler KG, Reichenberger R. (2009) Entwicklung des Raumedic TD1 readP, ein erster Schritt auf dem Weg zum idealen, telemetrischen Hirndruckmesssystem. Sektionstagung, Congress Proceedings, Homburg, Germany, p 56Google Scholar
- 12.Mnomani L, Alkharabscheh AR, Al-Zu’bi N, Al-Nuaimy W (2009) Instantiating a mechatronic valve schedule for a hydrocephalus shunt. Conf Proc IEEE Eng Med Biol Soc 31:749–752Google Scholar
- 13.Richard KE, Block FR, Weiser RR (1999) First clinical results with a telemetric shunt-integrated ICP-sensor. Neurol Res 1:117–120Google Scholar
- 16.Walter M (2002) Mechatronische Systeme für die Hydrozephalustherapie. Shaker, Aachen, pp 29–58Google Scholar
- 17.Walter M, Jetzki S, Leonhardt S (2005) A model for intracranial hydrodynamics. In: IEEE annual engineering in medicine and biology conference, Shanghai, Congress Proceedings, pp 5603–5606Google Scholar