Published online: 6 June 2018 © Taiwanese Society of Biomedical Engineering 2018
Over the last few years, medical device design has vastly benefited from the integration of finite element analyses in the product development process.
The finite element method (FEM) is a numerical method used to solve boundary value problems. This method adopts an approach of computing reactions over a discrete number of points across the domain of interest.
For medical design, this typically translates towards verifying device performance in a virtual domain that is representative of its planned real-life application.
A user may leverage results from such an analysis to interpret device performance and make educated recommendations for improvement and optimization.
Moreover, predictions of initial and long-term device performance in vivo may also be derived from FEM results often through a multi scaled and iterative analyses which may subsequently lead to better prepared in vivo studies
A key acknowledgement that enables such post-processing realizations is having an experienced user working with an interdisciplinary team.
Such a team may then confidently navigate through the many advantages and disadvantages put forth by this virtual test platform which continues to grow in popularity.
Advantages
The advantages of FEA in the medical device arena are many. The most attractive being the speed at which FEA can enable early device performance testing prior to costly prototyping and bench testing.
Correspondingly, integration of the FEM process into product development may reduce costs over the product development cycle. Such savings come to fruition by way of tentatively speeding up the process and reducing bench testing iterations.
Disadvantages
The disadvantages of the FEM for medical device design reside mainly with the high expertise required to properly navigate the computational platform while avoiding making costly mistakes from misinterpretations.
A skilled analyst is required to make effective use of the finite element method.
Regulatory Concerns
The status of FEA in the eyes of the regulatory bodies such as the Food and Drug Administration (FDA) in the United States of America or more specifically the branch of the Center for Devices and Radiological Health has taken some large steps towards FEM integration in product design dossiers.
In particular, for many years industry has sought to leverage computational modeling such as FEA simulations towards support design safety and effectiveness in areas of fluid dynamics (ventricular devices) and solid mechanics (spine, knee, hip implants, etc.).
In reaction, the FDA has drafted, in 2014, and later issued, in 2016, a guidance document entitled “Reporting of Computational Modeling Studies in Medical Device Submissions”.
Briefly, this public document provides informal guidelines on how to fully describe the modelling technique adopted and how it adheres to software quality assurance and numerical code verification expectations generically and then specifically to certain fields of application such as solid mechanics, for example.
It is nevertheless apparent, with the growing adoption of FEM methods in medical device design and development, that regulatory bodies will adapt to these new trends.
To this point, the FDA has been collaborating with many leading groups in this field on a V&V40 ASME standard (Verification and validation in computational modeling of medical devices) document expected to released in 2018.
This will elevate computational testing to equal consideration as bench, animal, and human testing currently receives—each testing method providing their specific advantages, disadvantages, requirements and expectations.
Norman T. Neher, P.E.
Analytical Engineering Services, Inc.
Elko New Market, MN
www.aesmn.org