Design of Medical Devices That Meet Contradictory Requirements

Abstract

Background: Today vitally important medical devices are expected to meet diverse and increasingly stringent requirements, in order to ensure their dependability in scenarios which can be life-critical. These requirements can often be contradictory in nature, presenting additional challenge to the designer. Method of Approach: In this article, discussed are two approaches to address contradictory requirements to medical de- vices: resolving contradictions and advanced Finite Element Analysis (FEA) modeling. First, it is shown how the contra- dictions can be resolved by separating the contradictory requirements in space, in time, and amongst the elastic parame- ters of the material. The generated designs still need be validated first by advanced modeling. Two factors make FEA modeling of medical devices especially important: risks or difficulties in producing experimental data and unknown sensi- tivity of the design characteristics to different parameters of the device and factors in the human body. Discussed are the selection of the material models and boundary conditions and sensitivity of the results to the parameters of the model. Resolving contradictions and FEA modeling should not be contraposed to each other; they work more effectively in tan- dem. Results and Conclusions: These approaches were applied to the development of peripherally inserted central catheters (PICC) and retrievable blood clot filters. The generated novel designs were protected by US patent applications. The re- sults obtained in LS-DYNA and other packages are compared with the available experimental data for the kink test and material response. The presented approaches can be used in the design and optimization of medical devices subject to stringent requirements or with enhanced properties.