Reducing Risk of Medical Products Through Prototyping

 In Human Factors & Usability Testing, Medical Product Design

Prototypes are the cornerstone of medical device development. They are powerful and important tools that transform ideas, thoughts and theories into something real. Prototypes also become a catalyst for deep collaboration and clear communication.

It can be overwhelming, however trying to keep track of the variety and purpose of the prototypes used in product development. This is especially true when developing a medical product that must adhere to regulatory guidelines or be utilized across development teams with differing levels of engagement; or both.

MindFlow’s prototype program integrates FDA regulation with our organized Guideway™ development structure, allowing for valuable and efficient feature development while managing risk and maintaining team alignment.

What is a Medical Product Prototype?

At MindFlow, we use the term prototype to mean anything that is created to test a specific concept. This could be something as simple as a mock-up foam handle for human factors testing or as complex as a functional heart valve for life-cycle testing.

We categorize prototypes by the phases of our Guideway™ medical product development process: Strategy, Development, and Transfer to Manufacturing. The prototypes used in the Strategy phase demonstrate core concepts and provide high-level insight to align the vision and requirements for the product. The prototypes in the Development phase realize the strategic vision and specific product requirements. These development prototypes iterate the concepts and features to a point that they look and function like the end product. In the Transfer to Manufacturing phase, the prototypes are production equivalent – nearly identical to units that would be coming off an assembly line. This allows for testing that is as realistic as possible.

Each phase has specific prototypes that aid the development process, at the appropriate resolution, for the current state of development.

Phase 1 – Strategy

Kicking off the Strategy phase at the outset of a project, there are many potential development paths. The purpose of the phase, however, is to focus the direction of development to best address the goals of the project. In Phase 1.1 of the Guideway™, we diagnose project readiness and create a plan of action. In Phase 1.2, we prescribe a design strategy, which is aided by two specific types of prototype:

Breadboard prototypes illustrate in generic terms how the technical solution works. Breadboards are used to highlight the conceptual differences among competing technologies. They can materialize in literally any form, so long as they plainly show how the solution solves the problem. Even a product that already exists but needs updating can serve as its own breadboard. In some cases, a breadboard prototype is required in clinical feasibility trials.

Configuration prototypes expand on the breadboard, only to show different variations of the product architecture. Instead of having an interface with two control knobs, a different configuration could have a small digital touch interface. These configuration models apply to all topics of development. Multiple handle shape configurations can determine ease of use or fatigue-related issues in ergonomics field studies. Different valve configurations can show optimal flow of humidified air to a patient’s lungs in flow analysis testing.

The main purpose of configuration prototypes is to find the variation of product architecture best suited to the technology and project goals.

Phase 2 – Development

Once a configuration direction has been prioritized, defining and developing the conceptual features and details of the device can begin. Concept development identifies and establishes important features, all while considering potential manufacturing constraints. In Phase 2.1, we define the vision for the design.

Concept prototypes aid in formative evaluation by determining aspects of features that resonate with users. They are also especially helpful for aligning teams and stakeholders to a design intent that will give direction to detailed development which comes next. These prototypes often have the appearance of manufactured product, typically realized as renderings, CAD drawings or finished 3D prints.

Once the design intent is finalized, we can begin to develop the important features to meet their required performance metrics. In Phase 2.2, we develop the concepts to the point that they can be qualified for further refinement.

Development prototypes focus on evolving specific features of the design to meet product requirements. Not enough airflow to meet the respiratory demand of a large adult? We can utilize development prototypes to iterate and advance a design to meet or exceed its specified flow metric. In this instance the prototype would need flow testing and analysis, necessitating a physical prototype with parts made by 3D printing or CNC milling, or sourcing commercial off-the-shelf parts. Digital prototypes like renderings or CAD drawings can be used as development prototypes as well, so long as they prove that the feature is capable of meeting its requirements.

The number of development prototypes is often tied to the complexity of the product being developed – greater complexity ≈ more development prototypes.

Once the iterated design features have been proven to meet performance requirements within reason, Phase 2.3 brings them all together for qualification as a whole.

Alpha prototypes combine all the features and functionality into one place: a build that begins to look and work like the vision set forth in the design intent. These prototypes serve to generate richer feedback than previous versions. Alpha builds are often utilized in formative evaluations, team and stakeholder alignment, and even early stages of clinical trials. Despite their functionality and aesthetics, the processes used to create an Alpha build have material and complexity limitations that can affect weight, durability, and finished appearance. These prototypes tend to be some of the most expensive of the product development process.

Material prototypes are simple, molded plaques of the materials to be used in the product. They are created as early in the development phase as possible in order to begin the long process of bio-compatibility testing. Each variation of the materials, including color or other additives, must have plaques made for testing. On average, we have 3-4 plaques created for each applicable party involved in the development of the product – on top of the amount required for testing.

Should the project include a disposable product that comes into contact with the body or anything going into the body, beta prototypes of the disposable packaging should be started as early in the development phase as possible as well. Bio-compatibility and packaging stability testing are surprisingly long lead activities.

Phase 3 – Transfer to Manufacturing

In Phase 3.1 of the Guideway™, we refine the qualified design with beta prototypes of the device and/or disposable. With higher fidelity parts and materials, Beta Prototypes aim to mitigate any risk that the Alpha builds were not able to address, such as weight, durability, and finished appearance. The fidelity of these prototypes is improved with the use of short-run manufacturing processes, such as injection molding, thermoforming, and die cutting. Although the manufacturing processes and hand assembly aren’t quite to production specification, Beta Prototypes are still of significant testing value. In some cases they are sufficient for verification testing, but more importantly, they are great for de-risking a design about to go into production through pre-testing in V&V, summative, and clinical aspects.

In Phase 3.2, we utilize the specified production methods to create pilot prototypes. These are virtually identical to the devices that will make it into the real world, should they pass testing. Minor production related issues can be fixed prior to testing, but by in large these should be complete, market ready products. These are the only prototypes qualified to complete verification & validation, summative, and clinical (pivotal) testing.

The list of prototypes in MindFlow’s Guideway may seem daunting, but taking an underdeveloped device to production risks hurting people—not to mention failing incredibly expensive testing and throwing away investment in manufacturing assets and activities. The iterative growth of the Guideway™ prototypes promotes communication and collaboration across teams and ensures FDA compliance as you advance through the medical product development process.


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