Medical Device Reliability

Our goal is to provide medical device manufacturers with critical data, new test structures, and standard test procedures to improve the quality, reliability, and consistency of active implantable medical devices. These devices, including pacemakers, cardiac defibrillators, and neural stimulators, have unacceptably high failure rates. For current devices, we are establishing new test requirements for discrete electronic components, which are often the source of failure. For next-generation devices, we are developing test structures to evaluate alternative packaging materials, which have unproven reliability.

• Medical devices represent a significant sector of the U.S. healthcare industry, with annual sales exceeding $13 billion. In the past decade, nearly 3 million life-saving cardiac-assist devices have been implanted. Improved acceptance testing will reduce device failures, improve patient quality of life, and decrease surgical cost.

• Next-generation devices will be miniaturized to promote biological acceptance and extend device lifetime. FDA approval hinges on demonstrated reliability. Standard test structures will enable quick evaluation of new packaging materials, allowing more direct comparison between manufacturers and reducing time to market.

Our Approach:

To improve acceptance testing of medical electronics, we are assessing a suite of potential acceleration factors and mapping the observed failure modes to those found in explanted devices. Multilayer ceramic capacitors are the focus, as changes in the properties of these components often result in device failure. We are also gathering critical data on next-generation packaging, where conformal coatings will serve as the primary interface between the device and the biological environment. Our initial focus is parylene, which is already used to coat neural recording electrodes and is proposed to replace metal canisters in implantable cardiac defibrillators.

For more information, see: 

• Drexler ES, Slifka AS, Barbosa, N, Drexler, JW, Interaction of environmental conditions: Role in the reliability of active implantable devices, Proc. ASME 2nd Frontiers in Biomedical Devices (2007)
• Anton, JM, Hooker, SA, Characterization of degradation mechanisms in neural recording electrodes, MRS Proc. Vol. 1009E (2007)
• Primavera A, iNEMI Statement of Work (SOW) Medical TIG, iNEMI Medical Grade Components Reliability Specifications Project (2006) http://thor.inemi.org/webdownload/projects/Medical/Medical_Components_Reliability//Med_SOW_Ver%205-0.pdf
• Hooker SA, Reliability of ultra-thin insulation coatings for long-term electrophysiological recordings,SPIE Vol. 6172, 617218 (2006)

• Established draft protocol for acceptance testing based on a comprehensive Failure Mode Effects Analysis of failed devices. This protocol is currently being validated using components provided by different suppliers.
• Developed new optical inspection methods to screen components for macroscopic failures during testing. This automated system enables acquisition of large data sets quickly.
• Tracked reliability of parylene coatings (of neural recording electrodes) as a function of local chemistry and identified conditions of use that resulted in significant localized degradation at the probe tip.