Medical Device Reliability

Our goal is to provide medical device manufacturers with critical data and standard test protocols 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 procedures to identify failure mechanisms and evaluate reliability of proposed alternative packaging materials.

• 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. Development of industry-accepted standard test procedures will provide the FDA with acceptance criteria, allow direct comparison between manufacturers, and reduce time to market.       
  

Degraded electrode

Our Approach:

To improve acceptance testing of medical electronics, we are assessing an accelerated test methodology that maps the effects of a suite of test parameters onto the observed failure modes found in explanted devices. Multilayer ceramic capacitors provide the model system to evaluate this process, 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.

• 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

• 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.
• Established draft protocol for capacitor acceptance tests based on a comprehensive Failure Mode Effects Analysis of failed devices. Identified five capacitor degradation behaviors, two of which result in capacitor failure.
• Identified Ultrasonic Resonance technique as potential non-destructive evaluation tool to detect onset of capacitor degradation.
• Presented accelerated capacitor failure test results to International Electronics Manufacturing Initiative (iNEMI) via webinar (2/2010).
• Presented test procedures and results to industry technical meetings: SMTA/MEPTEC (2009) and APEX (2010). Developed test protocols for parylene C. Designed custom test cell to evaluate permeability as function of test conditions.