Power for Implanted Medical Devices
Wednesday, April 11, 2:00-3:30, Ballroom B, University Hotel Minneapolis

Organizer: Leon Radziemski, Piezo Energy Technologies; Rajesh Rajamani, Professor of Mechanical Engineering, University of Minnesota

"Transcutaneous Energy Transmission for Implanted Blood Pumps"
William J. Weiss, PhD, Howard E. Morgan Professor of Surgery and Bioengineering, Penn State Hershey Medical Center

“Primary Battery Technologies for Implantable Medical Devices”
Michael J. Root, PhD, Fellow, Boston Scientific Corporation

“Battery-Less Wireless Instrumented Knee Replacement Implant”
Rajesh Rajamani, PhD, Professor of Mechanical Engineering, University of Minnesota

"Overview of Rechargeable Batteries for Implanted Medical Devices"
Prabhakar Tamirisa, Battery Research & Technology Group, Medtronic Energy and Components Center

Session Abstract:

Implanted devices such as various types of neurostimulators, pumps, and sensors are proliferating, and typically need sources of electrical power to function. The speakers in this session will provide an overview of the present state of delivering power for heart-assist devices, and projected advancements in energy harvesting, and primary and secondary batteries. Current and future applications of these power sources will also be discussed.

Session Organizer Bio:

Leon Radziemski, Piezo Energy Technologies
Leon Radziemski, PhD, is President and CEO of Piezo Energy Technologies, and an Adjunct Professor of Physics at the University of Arizona. During his career at Los Alamos National Laboratory and two universities, he studied wave phenomena in optics, lasers, and spectroscopy. For 12 years he was Dean of the College of Sciences at Washington State University. He has over 80 peer reviewed papers and two books published on those subjects. His latest interests are in the use of ultrasound as a wireless method of power transmission into a living body.

Rajesh Rajamani, Professor of Mechanical Engineering, University of Minnesota
Dr. Rajamani obtained his MS and PhD degrees from the University of California at Berkeley in 1991 and 1993 respectively and his B.Tech degree from the Indian Institute of Technology at Madras in 1989. Dr. Rajamani is currently Professor of Mechanical Engineering and a Senior Affiliate Faculty in Biomedical Engineering at the University of Minnesota. His active research interests include sensors and estimation for biomedical and automotive applications. Dr. Rajamani has authored over 80 journal publications and is a co-inventor on 7 patent applications. 

Speaker Bios:

William J. Weiss, PhD, Howard E. Morgan Professor of Surgery and Bioengineering, Penn State Hershey Medical Center
Dr. Weiss has been involved in the design and testing of mechanical circulatory support devices for over 30 years. He designed the transcutaneous energy transmission system (TETS) for the Penn State/3M total artificial heart and Arrow LionHeart ventricular assist system – the first wireless blood pump system to be used in humans. He has authored or coauthored over 40 peer-reviewed articles on circulatory support for adults and pediatrics.

Michael J. Root, PhD, Fellow, Boston Scientific Corporation
Michael Root is a battery electrochemist with over 22 years of experience in battery research and development as a team leader and hands-on individual contributor. He has worked with a number of primary and rechargeable energy storage systems for medical, consumer and OEM applications. He is listed as an inventor on nine US patents and authored technical papers, book chapters and a book on batteries and electrochemistry.

Prabhakar Tamirisa, Battery Research & Technology Group, Medtronic Energy and Components Center
Prabhakar Tamirisa is a Senior Scientist in the Battery Research & Technology group at the Medtronic Energy and Components Center. Prabhakar has a PhD in Chemical Engineering from Georgia Institute of Technology. His technical interests are in the fields of electrochemistry, surface science and polymers. 

Presentation Abstracts:

"Transcutaneous Energy Transmission for Implanted Blood Pumps"
Wireless energy transmission has been shown to be an effective and safe means to power implanted blood pumps, thereby eliminating a significant source of infection. However, widespread use is still limited. The requirements for these systems include peak and mean power capability, voltage regulation, coil misalignment, and EMI. This talk will discuss previous results with these systems in clinical use, as well as future applications.

“Primary Battery Technologies for Implantable Medical Devices”
Implantable medical devices have an important role in modern health care. They help patients manage and improve their health or, in some cases, survive life threatening disease conditions. Primary batteries power a wide variety of implantable therapeutic and diagnostic devices, including implantable pacemakers and defibrillators, neurostimulators, drug delivery pumps, hearing restoration devices and heart monitors. Advances in battery technologies and how they support the development of new or improved medical devices and features will be discussed. The chemistry and physical design factors of various implantable medical device batteries, as well as their performance attributes, will be highlighted. 

“Battery-Less Wireless Instrumented Knee Replacement Implant”
This talk presents the development of a battery-less wireless instrumented tibial tray for total knee replacement implants. An integrated piezoelectric stack in the implant is used to harvest energy from the knee forces due to walking. An ultra-low power technique is used to power capacitive force sensors and to power electronics for wireless transmission of measured forces. Experimental results with a gait simulation test rig show that adequate energy can be harvested from walking a few steps to be able to power continuous force measurement and wireless transmission for a duration of 10 seconds at 10 Hz.

"Overview of Rechargeable Batteries for Implanted Medical Devices"
This talk will present an overview of the current applications of rechargeable batteries in implanted medical devices and discuss key performance characteristics of rechargeable batteries for long-lasting applications. Modeling principles applied to understand the design space and performance over device lifetime will be discussed. Design and testing approaches for rechargeable batteries that may be of interest for future medical devices will also be presented.