Design Controls, Deconstructed
Industry terminology in the medical device field is so robust it could be declared an official language. And just as languages develop dialects that alter the meaning of a word or phrase depending on where it is spoken, the same is true in the medical device industry.
One common debate is the precise definition of the term “design controls.” The varied interpretations of that label create ambiguity.
Design controls are the means a medical device developer uses to prove that a product is safe, it works, and it is suited to the needs of the market. This post breaks down what design controls encompass, what they entail, and how your entire medical device initiative benefits from well-planned design controls.
Design Controls Background: FDA 21 CFR Part 820 vs. ISO 13485:2016
Design controls fall under FDA 21 CFR Part 820, Quality Management System Regulations. The term “design controls” originates from FDA. As it is the law in the United States, adhering to design controls requirements is required.
ISO 13485:2016 is, as you know, a voluntary standard. That said, since ISO standards are written with input from worldwide medical device regulators, ISO 13485 compliance is an acceptable approach that satisfies regulatory auditors. ISO 13485:2016 content related to FDA’s 21 CFR Part 820 is found in ISO 13485 Section 7.3, “Design and Development.”
The documents are very closely aligned; however, a major change to the ISO 13485:2016 update was the call for a risk-based approach to be taken when creating a quality system.
Thus, the QMS is the sum of all processes and operations you devise for a product, from the medical device design to its end use. Design controls are a segment of the overall QMS, albeit a significant one.
Design Controls Jurisdiction
Where do design controls rule? Because they are an FDA requirement, the obvious answer is “in the United States for any device marketed here.” For products marketed in other countries, similar design controls requirements exist, although, in keeping with our "dialects of medical device" theory, terminology may differ. ISO 13485:2016, as a global standard, helps align all markets in design control intent.
The new EU MDR requires a quality system that encompasses many FDA equivalents.
Canada requires quality systems to be ISO 13485:2016 certified (in addition to adherence with CMDSAS and MDSAP).
In short, adhering to ISO 13485:2016 standards is a strong start for every medical device manufacturer (MDM) planning to market in the United States, Canada, and EU.
Design Controls, Unpacked
The purpose of design controls is to detail the steps you will take to prove three things:
- This medical device meets a valid user need.
- This medical device is safe.
- This medical device and its production process meet regulatory requirements.
The actual design and development of the medical device originates from a user need. For instance, you’ve got an idea based on a healthcare need. This idea inspires…
Design inputs: “The physical and performance characteristics of a device” 1 that inform the medical device design. They are the DNA and building blocks of the medical device. Once determined, these characteristics outline the…
Design process: The methods used and procedures performed to result in the prototype medical device. The completion of this process leads to…
Design outputs: the most detailed engineering phase of the design controls process. Design control outputs are essentially the formula used to create your medical device—the complete “how-to-assemble” documentation. Design outputs ensure production of a consistently compliant, safe, effective device. The drawings and specifications set forth all product acceptance requirements, material recommendations, and required elements for proper/safe use. It is the complete assembly manual for your medical device. Design outputs result in . . .
A completed, viable medical device. Five steps took you from idea to innovation!
Along the continuum, there are three quality checkpoints to apply. Glossing over these steps can put regulatory approval at risk.
Chances are you’ve seen at least one version of this FDA-sourced Design Control Guidance chart. The chart is a great "at-a-glance" overview tool. It shows the medical device development journey and how each design control step connects.
The development progression we just discussed is shown on the chart as a five-step waterfall. Note, however, that the waterfall is surrounded by three formidable gatekeepers: Review, Verification, and Validation.
SCREEN SHOT 2020-01-08 AT 11.42.58 AM.PNG
© All rights reserved. Application of Design Controls to Waterfall Design Process. Health Canada. Adapted and reproduced with permission from the Minister of Health, 2019.
Navigating the Proving Grounds
Each step on the waterfall is subject to a design review before advancing. Design reviews ensure that each phase of development is assessed for safety and efficacy. Design reviews can also reveal risks or red flags that allow retooling now before an undetected issue compounds later. Inexplicably, many teams skimp on design reviews. The push to reach production is real.
That said, both FDA and ISO establish that design reviews are far more than just a hurdle to be jumped. FDA in Section 820.30 makes it clear that a design review is far more than a nice-to-have. It is considered formal documentation and proof of who, what, when, and how. And ISO agrees. This is strong encouragement to build a bulletproof design review step into your process.
Design Controls Verification and Validation
The chart shows design verification connecting design inputs and design outputs. It is the process by which we align where we started to where we ended up. Verification proves that the inputs correctly match the outputs. This is where testing comes in, providing objective evidence that no requirements were missed. Design verification testing formally documents the input-output results—confirming that you correctly designed the device.
And finally, we have design validation. The chart shows validation connecting the finished medical device all the way back to the original idea. While this may seem absurd on one level, it is the essence and DNA of what we do. Validation is another perspective on testing: Does this medical device fill the user need that inspired it, correctly and effectively? And in its use, is it answering the user’s actual need? This step uses test suites, test cases, or clinical trials to wrap up the journey, clearing it for approval and marketing.
The documentation and findings prepared throughout the design controls process is the basis for your design history file (DHF). The DHF provides critical traceability in the post-launch product life cycle. Any regulatory inquiry can be answered by tracing through the design history file. Traceability has long been a best practice. ISO 13485:2016 elevates it to a requirement.
More than ever, regulators look to design controls as the resource by which to gauge their response to your medical device. Consider them the sherpa of your journey.