Medical Device Industry

Uncertainty Quantification in the Medical Device Industry

From design to implementation, uncertainty can be found throughout the medical device industry. As no two patients are the same, engineers and managers need to know how the device functions under multiple operating conditions with an acceptable level of confidence. Other uncertainties can come from manufacturing variations such as imprecise equipment, varied raw material properties, and heat treatment processes. These variations lead to uncertain performance and may result in compromised parts or decreased service life. Uncertainty Quantification (UQ) can be used to better understand, manage, and reduce these potential sources of uncertainty for more efficient device design, manufacture, and maintenance, and to improve the safety and effectiveness of the device.

SmartUQ Medical Device Use Cases

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  Medical Device Deployment Analysis

  Patient anatomy, material properties, and manufacturing tolerances influence forces, stresses, and fatigue in many surgical and embedded devices. Detailed simulations are expensive to run across many combinations.

  SmartUQ selects informative simulations and builds surrogate models to explore applications like deployment responses. Sensitivity analysis and uncertainty propagation help engineers identify influential variables and prioritize further testing.

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  Orthopedic Implant Design

  Implant geometry, loading conditions, and bone-property variability affect predicted stresses and micromotion, complicating comparisons among design alternatives.

  SmartUQ accelerates structural design studies using surrogate models and evaluates the effect of uncertain inputs, helping engineering teams compare candidate designs before detailed verification.

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  Device Model Calibration and Validation

  Limited bench-test data and measurement noise make it difficult to distinguish uncertain model parameters from discrepancies in simulated device behavior.

  SmartUQ calibrates model parameters against physical measurements and quantifies uncertainty in predictions. Comparison with independent validation data supports assessment of model credibility for the intended engineering use.

Medical Device Simulation Challenges

To adequately perform Verification and Validation (V&V) for a design as suggested in the FDA guidance, these simulations must be done under a variety of operating conditions to account for uncertainties like patient-to-patient and manufacturing variability. Very large simulation batches are necessary to acquire an adequate number of samples for statistically significant analyses such as sensitivity studies and input uncertainty propagation. Also, trade-off studies and design space exploration require numerous simulation runs to capture QOI responses to changes in design parameters. Both initial design studies and V&V design thus often necessitate high performance computing (HPC) resources and substantial computation time. Fortunately, there are advanced analytics tools like SmartUQ that can help reduce the computational burden of modeling in the medical device industry.

SmartUQ Solutions

SmartUQ can be used in the design of new devices or the analysis of existing devices, from pacemakers and hip implants to MRI machines. SmartUQ provides guidance on testing and sampling as well as predictive models which complement high fidelity simulations and physical testing. These predictive models, i.e., emulators, are trained using a minimal number of simulation or physical test runs and can then be used to predict at new operation points. These emulators can accurately handle complex nonlinear behavior and high dimensional systems faster than previous solutions, without resorting to HPC. SmartUQ has a variety of emulator/surrogate model types developed to handle complex data types including high-dimensional inputs, functional or transient responses, point cloud or mesh data, and discrete inputs.

SmartUQ and Model Validation

With the push for V&V, a number of leading organizations have formed dedicated medical device V&V working groups. These include the American Society of Mechanical Engineers’ (ASME) subcommittee V&V 40, which provides standardized medical device V&V procedures. In fact, ASME V&V 10 have developed a validation workflow as shown in the below chart. This workflow incorporates uncertainty analysis to validate the simulation model across all possible scenarios. SmartUQ’s tools including DOEs for calibration of a simulation model with physical data, statistical calibration, sensitivity analysis, and uncertainty propagation, are the building blocks of the V&V workflow.

Adopting the V&V workflow can have the effect of not only meeting regulatory requirements but also decreasing the amount of expensive physical testing required in later design stages, reducing the time to market for new products, and increasing the confidence in models and new designs.

To learn more about UQ and medical devices, check out the white paper “Uncertainty Quantification for the Medical Device Industry” which includes an end-to-end coronary stent uncertainty quantification and model validation study.

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