What are the correct design control phases for medical device development? To properly answer that question we have to step back and look at the bigger picture of product development processes and medical device regulations.
There’s a simple answer to the question if we are only talking about your company and its quality system–the correct design controls phases are the ones defined in your quality system. Easy. However, if we consider the question more broadly, it’s more complicated to answer. Medical device companies are free to define the design control phases the way they want. FDA regulations define the general requirements for design controls (and the ISO 13485 quality management standard does as well) but those regulations do not require a certain set of design control phases, or any phases at all. Yes, that’s right. You can comply with all the design control regulations without having any phases at all in your product development process.
Over the past 20 years, I’ve worked in quality systems with as many as 11 phases and as few as zero phases. I don’t recommend either extreme but more important than the number of phases is the focus of each phase and what’s required to complete it and transition to the next phase (to “pass the gate”). So it’s helpful to analyze why we have phases and gates in product development.
Reasons for a Phase-Gate Structure
What are the advantages of a phase-gate structure for medical device development?
- Coordinate the work across multiple disciplines (Mechanical Eng, Electrical Eng, Software Eng, Clinical, Human Factors, Manufacturing, Regulatory, etc.)
- Manage complex dependencies across development activities; for example, making sure the product design is complete before starting formal V&V testing
- Manage project risks and controls allocations of resources–to avoid investing significant resources before knowing that a product design will be successful
- Ensure compliance to regulations and applicable standards
- Increase visibility of project status and issues for senior management (governance)
Note that what’s important to do at the beginning of medical device development and near the end are going to be quite different. The design control phases should provide a framework for the product team that focuses their efforts on the right work at the right time, not just ensuring compliance and documentation.
Optimizing Design Control Phases
So I can’t tell you the exact set of design control phases that will work best for your organization and your products but I can give you advice and guidelines. Here are my recommendations to develop an optimized set of design control phases for your company:
- Describe each phase in terms of activities that the product team performs and goals for the phase; don’t simply list a set of DHF documents for each phase
- Make the phase transitions (gates) meaningful to the project and the company. Completing a phase should correspond to significant reductions in project risk and changes to workstreams. This enables managers to plan resourcing appropriately as the project proceeds.
- Use as few phases as possible–each transition from one phase to another is expensive for every development project.
- Corollary to #3: For companies with an iterative product development process, make sure the iterations occur within a phase. Don’t iterate across phase transitions–that’s very expensive!
- Consider carefully the dependencies of different development activities and how best to integrate them efficiently. What’s needed for human factors testing? What’s needed for electrical safety testing? Etc.
- Decouple design reviews from the end of a phase. It’s ok to schedule one or more design reviews in the middle of a phase as well as at the end. Some companies make this explicit by having “Phase End Reviews” separate from design reviews.
- And, of course, make sure the phases include all the requirements for compliance with regulations and applicable standards (auditors are very helpful with this aspect of design control phases)
What’s meant by “significant reductions in project risk and changes to workstreams”? A good example would be preparations to start formal V&V. Since V&V testing involves expensive time-consuming activities, it’s important to ensure that all the prerequisites are completed before starting V&V. Completion of the product design (design freeze) is a crucial prerequisite, as well as other work. In the pressure of a typical medical device development project working under a tight schedule, it’s easy for a product team to be pushed into starting V&V before everything’s in place. Good design control phases should counteract this business pressure and provide the visibility to ensure all the necessary preparations (and documentation) are completed before V&V starts.
And don’t forget about Phase Zero. Phase Zero is technically not part of design controls but is a crucial part of developing a new medical device to start the product team in the right direction. For more information on maximizing the chances of success for every development project see this article: “Phase Zero on Steroids” in the links below.
Summary
It can be challenging to define the optimal design control phases but the work will benefit every development project for years to come. And if someone ever tells you, “That’s not what’s supposed to be in Phase 2!” you can answer that your Phase 2 has been optimized for your company’s needs and its products.
If you’d like to learn more, check out the links below or contact me and I’d be happy to explain the pros and cons of different design control options for your quality system.
More Information on Design Controls
- What Are Medical Device Design Controls? – a broad discussion of design controls and common misunderstandings
- Phase Zero on Steroids – a description of how to fully leverage this crucial front end of product development to maximize the chance of success for every product team
- Underestimating and Overestimating Design Controls – practical considerations on how design controls fit into medical device development
- Re-Entrant Design Controls: Managing Medical Devices That Are Never Finished – how to set up design controls to efficiently manage software-intensive, connected medical devices
- Adaptive Design Controls – modern processes designed to support development of complex, software-intensive medical devices; built on lean and agile principles