Simulation methods are used in device development as a means of evaluating functionality of design. They can give an indication of whether a design achieves its primary mechanical goal prior to prototyping. However, over and above prototyping, simulation methods can provide estimates of long-term functional behaviour that are time consuming and expensive to determine otherwise. Examples include stress/fatigue analysis and/or predictions of biomechanical behaviour of medical devices.
Simulation has been taking on a greater role in the design and regulatory approval of medical devices.
- Computational Fluid Dynamics (CFD) is specifcally written in as a method to assess hemodynamics in ISO's 5840 guidelines for testing of heart valves.
- The FDA initiated a Critical Path Initiative for the Standardization of Computational Fluid Dynamic (CFD) techniques in evaluating performance and blood damage safety in medical devices. Characteristics of fluid flow are seen as being predictive of longer term damage to blood.
- Both ISO 25539-2 for Vascular Stents and FDA guidance document 1545 for Non-Clinical Engineering Tests for Intravascular Stents recommend FEA as a method for conducting stress/strain analysis of new stent designs.
- Additionally, the ASTM has set up the V&V 40 Committee for the verification and validation in computational modeling of medical devices.
Zymetrix has expertise in three areas of simulation and computational analysis;
Computational Fluid Dynamics (CFD): Used to estimate the effect of mechanical structures on fluid flow. Zymetrix has experience in both kinematically driven models, as well as models incorporating fluid-structure interaction. Zymetrix has developed a fluid-structure CFD model to simulate hydrodynamics and stresses for prosthetic heart valves.
Finite Element Analysis (FEA): Used to estimate component stresses, strains, and/or displacements under internal and external loads. Zymetrix has experience in using FEA to conduct stress/strain analysis of vascular stents. In addition, our collaborator, Dr. Steve Boyd, has extensive experience in using FEA to study the structural behaviour of bone and has commercialized a software package specifically aimed at developing FE meshes of bone from CT images [Numerics88].
Particle Image Velocimetry (PIV): Although requiring experimental measures, PIV is a computational method for calculating objective variables to describe fluid flow. It is used extensively in evaluation of cardiovascular devices.