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 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 have also designed and tested an in vitro circulating-cell-culture setup to model cellular occlusion process. Using our in vitro system, we seek to evaluate the performance of our MEMS devices in preventing and removing cellular occlusion.
Our specific aims are as follows: (1) to determine the rate of occlusion using conventional catheter, microfabricated pores, non-actuated devices, and fully-actuated devices; (2) to determine the optimal parameters of activation (i.e., angular deflection, frequency of activation, and activation duration) for maintaining flow through pores; and (3) to integrate our magnetic microactuators into a commercial ventricular catheter and to test their pore-clearing efficiency. The successful completion of this research will result in an advanced medical device that will improve the lives of hydrocephalic patients by decreasing the probability of shunt obstruction. Moreover, our remote activated self-clearing device technology may easily be translated into other medical applications where obstruction in the lumen or pore is a source of complication (i.e., other long-term catheters, arteries, veins). ? ? ?
| 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 |
