Developing a medical device requires sensitivity to the delicate balance between usefulness, usability, desirability, and manufacturability. Every medical device must be useful (meet a need) and usable (easy to understand and manipulate properly) in order to gain regulatory approval. The elements of desirability (customer appeal) and manufacturability (efficient and reliable production processes) must also be woven into a medical device’s identity to satisfy business objectives.

Fig. 1 – Key components of stakeholder satisfaction.
Many stakeholders must be satisfied during the development of a new medical device. The term “stakeholder” refers to a person or group having the ability to affect or be affected by a development team’s actions. The priorities of designers, engineers, marketing team members, manufacturing representatives, regulatory specialists, and end-users must be considered simultaneously from inception to commercial release to create a complete story. All stakeholders share common expectations of product quality, safety, reliability, and dependability. Each has a different definition of how these are expressed and measured, making the development process complex and multi-faceted.

An integrated product development process that truly combines Human- Centered Design principles with a solid Design for Manufacturing (DFM) and Design for Assembly (DFA) philosophy will simultaneously address usefulness, usability, desirability, and manufacturability. When handled properly, the probability of a product’s success will be dramatically improved. (See Figure 1)

What is Human-Centered Design?

A Human-Centered Design approach includes the professional disciplines of Design Research, Industrial Design, and Human Factors Engineering. These disciplines all strive to serve the needs of a product’s end user, but they require different skill sets and approaches.

Design Research activities are typically conducted at the front end of a development cycle in order to establish a firm foundation for future design work. These activities are included to discover the needs and dreams of end users, uncovering attributes that will resonate with them on an emotional level. Common Design Research methods include targeted interviews, contextual observation (i.e., witnessing a surgical procedure in an operating room or shadowing a diabetic patient through their daily testing and insulin injection routine in the home), participatory workshops, analogous product benchmarking, and trend tracking. These processes allow a crossfunctional development team to appreciate circumstances, environmental conditions, and user expectations in an effort to identify design opportunities. Discoveries made through Design Research inform the development process, improving the likelihood of success upon market introduction.

Shown in Figure 2 are participants interacting with block models during a participatory workshop. The block modeling toolkit was created to enable quick 3D expression of ideas during exploratory sessions. Users can quickly attach building blocks to a base, creating a tangible representation of a potential medical device to accompany sketches or verbal descriptions. Buttons, dials, or connectors may be attached to a block model to represent user interface touchpoints and stimulate conversation.

Fig. 2 – During a participatory workshop, team members use block models to stimulate ideas and discussion.
Industrial Designers build upon the solid foundation of Design Research, translating insightful discoveries, product performance goals, and marketing objectives into tangible concept directions. Product form, user interface, ergonomics, aesthetic detail treatment, material selection, and manufacturing approaches are all considered during the Industrial Design phase. The process typically begins with collaborative brainstorming, involving a cross-functional team and leveraging the talents of multiple professional disciplines. Through an exploratory and iterative methodology, In dustrial De signers narrow their focus to a manageable set of conceptual embodiments that may be evaluated through illustrations, preliminary CAD models, and physical prototypes.

Human Factors Engineering (HFE) methods are applied throughout the development cycle to mitigate productrelated safety risks and make design decisions. The FDA and other regulatory organizations expect HFE activities to be included throughout the design phase to control risk and ensure product effectiveness. HFE activities may include testing of early concepts with representative users, usability and product handling studies, and final verification/validation studies to meet regulatory requirements. Proper planning, execution, and documentation of HFE practices throughout the development process should streamline the submission process for regulatory approval.

Human-Centered Design activities may be scaled to match the program requirements and objectives. Small-scale efforts may include a brief definition of basic user profiles, fundamental contextual influences, and general market space dynamics. Large-scale efforts may involve additional activities such as indepth user interviews covering multiple geographic regions, co-creation of conceptual mock-ups with potential users, exploration of multiple product embodiments through a detailed Industrial Design phase, and a series of usability studies with representative users handling functional physical prototypes. Regardless of the scope and scale of the program, a well-rounded design and engineering team will keep the needs of their end user(s) in mind at every phase of the product development cycle.

The Human-Centered approach is not limited to a single phase, nor is it a standalone module that can simply be attached to the front end of a program. It needs to be embedded into the cultural fabric of an organization in order to be effective.

Design for Manufacturing (DFM) and Design for Assembly (DFA)

Fig. 3 – Integrated product development cycle.
Design for Manufacturing (DFM) and Design for Assembly (DFA) are also foundational elements of a robust product development process. Much like Human-Centered Design principles, a sound DFM/DFA philosophy must become a cultural mindset, becoming deeply ingrained within all phases of development. While HFE evaluation throughout the process is typically focused on the user’s experience, DFM and DFA are focused on manufacturing quality, cost, and risk.

The most successful product development teams ask probing questions at the onset of a program to clearly understand an array of relevant variables including anticipated production volumes, physical performance requirements, cost targets, quality standards, and potential compatibility issues. An appreciation for these elements will direct a development team toward the most appropriate manufacturing materials and processes for a given medical device and result in a robust manufacturing strategy.

Certain aspects of DFM, such as design guidelines for molded plastic or metal parts, have proven manufacturing pro cess principles behind them, and applying just a handful of established DFM guidelines for molded parts can prevent a majority of design issues. The same can be said for DFA, in which planning for manual, semi-automated, or automated assembly from the early stages can prevent issues that would otherwise be found during clinical, pilot, or manufacturing launch builds when mitigation of issues becomes much more costly. Designers, engineers, and manufacturing representatives must collaborate early and often to develop designs that meet targeted quality and cost objectives, and other established program goals.

A longstanding estimate is that 80 percent of product cost, and therefore manufacturing risk, is determined during the first 20 percent of the product development process. As such, whether the commercialization strategy involves in-house manufacture or the use of a Contract Manufacturing Organ ization (CMO), the early involvement of the manufacturing team to provide DFM/DFA input is critical to program success. Early manufacturing involvement will not only provide expertise to leverage in reducing product cost, lead time, and risk, it also promotes early learning and buy-in by the manufacturing team.

Further, many leading CMOs have experienced design engineers or even complete design centers to either augment the OEM’s design team or take the lead in product development. While the leading CMOs do not typically own intellectual property or develop their own branded products, their underlying strength in integrating DFM/DFA into the product development process may provide a solution to an OEM’s development needs.

A Common Thread

Medical devices have become smaller and smarter. Expectations of regulatory organizations have been elevated. Healthcare providers and patients have come to expect higher levels of sophistication from the products they use. Development timelines and budgetary constraints have become more demanding. As these trends continue to evolve, the benefits of an integrated product development approach become increasingly clear.

The integrated product development process is not linear. (See Figure 3) Human-Centered Design, Design for Manufacturing, and Design for Assembly are philosophies that remain constant throughout the full development cycle. Design Research informs the process most actively from the point of kickoff through industrial design and engineering phases. HFE activities are relevant throughout the development cycle, but are most heavily concentrated during industrial design, engineering, prototyping, and design verification testing phases. DFM and DFA provide consistent and regular efficiency-minded perspective during all phases of development. All of these principles work handin hand to inform the development process and streamline the path toward commercialization.

The common thread that binds these elements together is risk mitigation. When a product is delightful to use, adoption and compliance become more likely. When a device is efficient and cost-effective to produce, the process becomes more predictable and the overall product quality improves. When risks are effectively mitigated, all stakeholders can feel satisfied and the common expectations of quality, safety, reliability, and dependability are realized.

The article was written by Bill Welch, Chief Technology Officer, and Jeremy Odegard, Human-Centered Design Team Leader, Phillips-Medisize, Hudson, WI. For more information, Click Here .