The most common treatment for patients with hydrocephalus is the surgical implantation of a cerebrospinal-fluid (CSF) shunt. Unfortunately, this device, which is critical for lowering intracranial pressure, has a substantial failure rate. A leading cause of failure is the obstruction of the ventricular catheter. Building upon our investigation of ventricular- catheter obstruction and our experience with magnetic MEMS, we seek to realize a self- clearing ventricular catheter through the integration of magnetic microactuators that are capable of mechanically maintaining a clear ventricular catheter without requiring an implanted power supply into the shunt. The work we propose will focus primarily on preventing and/or reversing proximal ventricular-catheter obstruction. In most cases, catheters become obstructed due to the accumulation of inflammatory cells that adhere to the proteins on the surface of the catheter. The goal of this project is to design a ventricular catheter that will resist occlusion due to cellular accumulation through the use of micromachining and micro-electro-mechanical systems (MEMS) technologies. We previously have demonstrated the operation of MEMS magnetic microactuators in biological fluids without the need for a directly wired power supply or control electronics. We propose that microactuator technology could be used to mitigate catheter obstruction in a permanently implanted device.
Our specific aim i s to use an in vitro setup to analyze the obstruction and the obstruction-clearing capability for the prototype MEMS-enabled design.

Public Health Relevance

Although patients suffering from hydrocephalus frequently have a catheter implanted into their brain to drain away the excess cerebral spinal fluid, these devices can clog after years of use and require another brain-surgery procedure to remove the old catheter and implant another one.
The aim of our research is to integrate magnetic microactuators into the catheter that can be driven using an external source for the magnetic field, which eliminates the need for implanted wires or power supplies, and that can generate enough force to disrupt and dislodge the obstruction so that flow can be re-established. By producing a self-clearing microactuator-enabled catheter and operating it to greatly decrease the probability of shunt obstruction, patients should require fewer replacement surgeries, face less risk and stress associated with surgeries, and spend more time enjoying the benefits of a properly functioning shunt.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Exploratory/Developmental Grants (R21)
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Neurotechnology Study Section (NT)
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Hicks, Ramona R
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University of California Los Angeles
Engineering (All Types)
Schools of Engineering
Los Angeles
United States
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Lee, Hyowon; Kolahi, Kameran; Bergsneider, Marvin et al. (2014) Mechanical Evaluation of Unobstructing Magnetic Microactuators for Implantable Ventricular Catheters. J Microelectromech Syst 23:795-802
Lee, Hyowon; Xu, Qing; Shellock, Frank G et al. (2014) Evaluation of magnetic resonance imaging issues for implantable microfabricated magnetic actuators. Biomed Microdevices 16:153-61
Lee, Selene A; Lee, Hyowon; Pinney, James R et al. (2011) Development of Microfabricated Magnetic Actuators for Removing Cellular Occlusion. J Micromech Microeng 21:54006
Lee, Hyowon; Xu, Qing; Ephrati, Jeremy et al. (2010) MRI compatibility of microfabricated magnetic actuators for implantable catheters: Mechanical evaluations. Conf Proc IEEE Eng Med Biol Soc 2010:907-10