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Innovative Iteration for Medical Device Design

As the impacts of COVID-19 continue to wane, including crippling supply chain disruptions, early-stage product development is on the rise. Startups, especially, have been subjected to heavy valuation pressure and limited funding opportunities—in response they have adjusted their development strategies to make capital last longer. Although these lingering effects are improving, many medical device manufacturers (MDMs) would still like to see more stability before they invest heavily in product development.

When determining how to spend their resources (including allocations for product design) in a tense funding environment, MDMs seek the classic value drivers of rapid prototype iteration, speed to market, and experienced partners that can ensure reliable production ramp-up.

“Today’s innovators need to make every dollar count while operating against tight forecasts, and we are doing everything we can to be their partner of choice in early-stage development,” said Dave Rezac, vice president of AGILE Product Development for Resonetics, a Nashua, N.H.-based provider of advanced engineering, prototyping, product development, and micro-manufacturing services to the medical device industry. “When times are tough for startups on the front lines, we see the value of a vertically integrated offering that ensures continuity of supply from prototype through market introduction and launch play better than ever.”

More cautious MDMs are focused on operating margins and cost controls with their product portfolios. “Today, we are seeing more requests to help keep current products on the market for as long as possible,” said Jenna Joestgen, director of engineering solutions, healthcare/life sciences for Plexus Corp., a global provider of design and development, new product introduction, manufacturing, and sustaining services for the medical device industry. “Product design is being asked to happen under the heaviest of constraints to keep non-recurring engineering as low as possible, leverage existing tooling, and decrease unit price.”

Consolidation continues within the medical device industry and has its own impacts on product design and development.

“Consolidation activity has not improved the situation and in some cases, it has caused problems,” said Richard Brown, principal engineer for Engineering & Quality Solutions, a Colorado Springs, Colo.-based contract engineering and product development company focused on orthopedic trauma and spine implants and surgical instruments. “We had instances recently where machining vendors that were manufacturing either prototypes or production product were purchased and merged into other companies. The result was longer lead times after purchase orders were issued and in work.”

These delays compelled the company to investigate other options, with success. For example, Brown can now get prototypes within a few weeks from the quick-turn bureaus that now exist. “These are for initial evaluation and do not necessarily need to come from approved medical manufacturing vendors,” he said. “However, with production work, we have to look harder to find sources that can be approved and placed on the approved supplier list before we can commit to placing those orders.”

Current Trends

In previous generations/decades, medical devices were mostly contained in hospitals and outpatient medical facilities. This trend is changing rapidly. “Tele-health and wearables are trending to improve and distribute medical devices,” said Andrew Gosline, senior systems engineer for Simplexity Product Development, a San Diego-Calif.-based engineering design firm that specializes in the design of wearables, medical devices, and molecular diagnostic equipment. “For example, early continuous positive airway pressure (CPAP) machines looked like clunky, noisy toasters. Now they look like stylish clock radios with cloud-based data backup and portable batteries for camping/travel.”

For prototyping, additive manufacturing/3D printing (AM/3DP) and room temperature vulcanized molding techniques continue to improve, allowing designers to fabricate fully functional prototypes without the need for hard tooling. “Faster iteration times with earlier feedback from patient populations and physicians means that device therapies can be more effective and comfortable, which improves outcomes and adherence,” said Gosline.

Plenty of innovation is occurring in the areas of neurovascular catheters, energy-based therapeutic devices, minimally invasive surgical devices, and targeted delivery systems. A common feature needed for many of these devices is a custom laser-cut hypotube. “Based on device requirements, we can design cut patterns that optimize flexibility and trackability, while maintaining concentricity in a tight bend and optimizing torque transmission,” said David Schechter, president and CEO of Meddux, a Boulder, Colo.-based contract manufacturer specializing in medical device product development and contract manufacturing of complex, minimally invasive surgical and targeted delivery devices. “Laser-cut hypotubes can also be used to engineer high-force articulating and steerable shafts without the need for separate pull wires.”

From the digital technology perspective, Internet of Things (IoT) technologies are being used in product development for scale and miniaturization, sensor integration, advanced diagnostics (data integration and closed-loop therapy), real-time diagnostics, and imaging advancements. Artificial intelligence (AI) and robotics are driving growth across many medical device sectors, including minimally invasive devices. Bluetooth/wireless/cloud capabilities are also a growing trend. “It is becoming increasingly common for devices to be connected,” said Gosline. “This allows data aggregation for analysis by physicians and continuous improvement via over-the-air [OTA] firmware changes.”

In the orthopedics/spine market, AM/3DP is becoming the preferred method for creating porosity in implants to facilitate bone growth. For spinal implants, new designs of surface geometries are also a growing trend. “These surfaces include trabecular structures that are designed to mimic cancellous bone with the goal of improving osseointegration and ultimately fusion,” said Victoria Trafka, president and principal engineer for Engineering & Quality Solutions.

AM/3DP is also being used for absorbable implants. Currently, the majority of absorbable implants are still prototyped using traditional injection molding and textile processes. Poly-Med, an Anderson, S.C.-based vertically integrated manufacturing partner that specializes in the design, development, and manufacture of custom absorbable medical implants, has had success with reducing the cost associated with prototyping and screening designs by using fuse filament fabrication (FFF) 3D printing, although not without challenges. “3D printed parts can replicate many of the properties of traditionally manufactured parts, but are typically not as strong as injection-molded parts or textiles made from oriented fibers,” said Scott Taylor, chief technology officer for Poly-Med. “3D-printed parts also degrade faster than injection-molded and textile parts that have used the same downstream processing methods—for example, heat setting, drying, and sterilization.”

Speed, of course, is a top priority in early-stage development. Even though supply chain lead times have improved slightly over the previous year, “realistically the lead times to support rapid iterations in product development are still too long,” said Schechter. “The availability of off-the-shelf components from online stores like Chamfr has been a significant advantage for early design and prototyping. We also are seeing rapid turn times for custom parts like laser-cut hypotubes and precision machining.”

Advancements in rapid prototyping and distributed means of production have further compressed prototyping iteration loops from months to weeks and, in some cases, just a few days—all of which improve speed to market. “Our investment in platform technologies like nitinol raw material, laser-cut tubing, and embedded sensors, along with development accelerators like our universal catheter handle, mean our customers can focus on the novel aspects of their therapy and progress through early-stage development faster, with more confidence,” said Rezac.

Also, over the past several years, sustainability engineering has become an important trend and requires product design engineers to focus on researching materials that can be used in production so the recycling options at “various institutions can be thoughtfully considered and implemented,” said Lorenzo Vaccarella, director of new product development for Paragon Medical, a contract design manufacturing organization that serves the medical device industry. “However, the selected material for sustainability engineering purposes must not compromise other product requirements, such as physical and mechanical properties, and usability requirements.”

What MDMs Want

Speed, quality, and expertise that help ensure first-pass success are always at the top of the MDM wish list. Increasingly, though, MDMs count on their contract manufacturers to also help with the validation and documentation of development processes and operational procedures.

“More than any other aspect of outsourcing the manufacturing of products, we hear that people need to keep everything on track—timelines, budgets, operational efficiencies, and delivery schedules,” said Hans Dittmar, director of marketing for GMI Solutions, a Mequon, Wis.-based provider of outsourced assembly and testing of electro-mechanical solutions and embedded computers for the medical device industry. “These more rigorous guidelines result in a need to balance these factors, so MDMs are shifting these responsibilities to their suppliers, which can be best managed through design for manufacturability. GMI has added resources that specifically concentrate on these activities.”

Joestgen agreed. While there is a list of common “asks” regarding new product features, “more MDMs want to know more about our control of the product design process itself,” she said. “They want to know if we can design their product at the price and schedule we quoted. MDMs are under immense pressure to stick to business case assumptions when approving the development of a new product. The sensitivity of these assumptions has greatly increased, and as a result, each change or risk realized could trigger a discussion around the viability of the overall program.”

The new product features MDMs want include networked physiological/medical measurement devices that can aggregate de-identified data for population analysis by epidemiologists or physicians. “As the biometric sensors improve,” said Gosline, “and wearable medical devices become more widely accepted, there is an exciting sort of ‘accurate-personal data-supported wearable industry’ that feels just about to boom. The combination of IoT and wearable biometric sensors makes this potentially excellent.”

Another way MDMs can save time and money is to utilize user-centered design. The process should start with a full understanding of the clinical use environment and any problems from the user and patient perspectives that need to be addressed. “User-centered design focuses on user profiles and journey maps to fully understand the entire clinical workflow and opportunities for improvement,” said Schechter. “This happens as an initial step in the design process to ensure requirements are well defined, users perceive value in the proposed product solution, and the product solution is addressable for the broadest group of targeted users. For MDMs, starting with user-centered design is essential to commercial success.”

MDMs want their contract manufacturers (CMs) to make next-generation products that are designed to improve what they already have on the market, which reduces risk and eases the final design approval process. “There seems to be a lot of caution around brand-new and revolutionary products due to uncertainty in the medical device space,” said Trafka. “In addition, with surgical centers and hospitals putting pressure on to lower prices, MDMs are asking for designs that can be produced at a lower cost, while achieving the same functionality.”

AM Advances

Product designers are consistently trying to find ways to reduce device complexity and variability to improve product reliability, patient outcomes, and overall performance. With respect to prototyping, AM/3DP continues to be a popular rapid prototyping process for medical devices. “With continuous advancements in materials, the 3D-printing library of materials continues to grow, offering product designers more flexibility when it comes to simulating the actual product material that will be used for production purposes,” said Vaccarella.

AM/3DP has had a revolutionary impact on the design of products, fixtures, accessories, and tooling. The ability to rapidly iterate designs has been extremely beneficial for manufacturers. “Instead of designing something as close to perfect as possible before investing the time and money to fabricate it, teams are instead thinking of very different approaches to a problem and trying several variants immediately,” said Dittmar. “This approach almost always allows for a better design in a much shorter time frame.”

The steady release of new materials for AM/3DP technologies pushes the boundaries of product design—especially by making truly useable prototypes. It was not long ago that placing a 3D-printed plastic implant or instrument in the hands of clients within a few weeks was considered state-of-the-art. However, those plastic prototypes did not have the qualities of the finished product and could not be truly tested in a surgical setting. “Now, with all of the materials we have available and the processing knowledge, we can get very close to the final qualities of the production implant or instrument in a few weeks,” said Brown. “This translates to faster feedback and shorter timelines and ultimately shorter time to market for new product lines.”

One of these new material platforms is Poly-Med’s Photoset, a first-in-class UV-curable, mechanically competent, fully absorbable material. Photoset can be used in digital light processing (DLP) and stereolithography (SLA) 3D printing applications to create high-resolution parts. Additionally, since SLA and DLP are more scalable than fused deposition modeling, this material allows for rapid prototyping of designs that directly translate into scaled and multiplexed manufacturing processes. “Thus, an R&D effort can avoid a 3D printing to injection molding transition, ultimately increasing speed to market, decreasing development cost, and unlocking unique designs for differentiated products,” said Taylor.

The advent of 3D-printable resins that are biocompatible and sterilizable is also having a strong positive impact on early-stage development. The ability to leverage printed componentry up to and beyond first-in-human milestones, while minimizing capital investment in the primary design, “helps startups stay lean and focused on the core functionality of their new device,” added Rezac.

Laser-Focused

As medical device products and components become smaller and more complex, with extremely tight tolerances, MDMs and their CMs utilize lasers to cut micron-sized features. In fact, some features can only be cut with lasers, expanding design options for engineers and designers. Lasers can remove material in virtually any shape or pattern.

An increasingly popular use of lasers is converting complex and high-performance catheters to laser-cut hypotubes, moving away from traditional braid and coil construction.

“Laser-cut hypotubes are changing the way catheters and minimally invasive instruments are designed and manufactured,” said Jay Vinson, co-founder of Symmetry Laser, a Davis, Calif.-based company that provides precision laser cutting and welding of hypotubes. “By using laser-cut hypotubes, engineers can now combine multiple components into one monolithic structure that dictates the flex profile, torque, and hoop strength of their device, all while maintaining the integrity of the inner lumen.”

This paradigm shift in component design has drastically simplified manufacturing, where devices can be designed in many cases with one or two different durometer polymers and eliminate complex and time-consuming braid terminations. “This significantly reduces touch time, scrap, and rework while greatly increasing production throughput,” Vinson added.

Meddux uses laser-cut hypotubes to reinforce catheters that need to be highly flexible, but still maintain concentricity and hoop strength. Typically, a catheter requires a lubricous inner layer or liner, most commonly a thin layer of polytetrafluoroethylene (PTFE). “A drawback to using a laser-cut hypotube, as opposed to a braid or coil reinforcement, is that it can be challenging to incorporate the lubricious inner liner,” said Schechter. “However, we have developed a proprietary process that incorporates a lubricous liner into the laser-cut hypotube construction, which mitigates this drawback for highly engineered catheter applications.”

Moving Forward

Ultimately, the goal for product design is to strike a balance between complexity/functionality/innovation, cost, and regulatory approval—with speed to market a constant consideration. Depending on the materials and level of complexity, some products (even new versions of legacy devices) can get delayed by the FDA approval process.

“Certainly, a key challenge in the medical product design space is constraining the device to the 510(k) pathway where there must be substantial equivalence between the new device and the predicate device,” said Gosline. “This causes device designers to create devices that are ‘innovative enough’ to draw attention but not ‘too new’ to require a more complicated and costly regulatory pathway.”

Taylor observes that many of the truly disruptive products and technologies are initiated by startup ventures, although these companies often lack the funding requirements to progress from proof-of-concept to 510(k) approval through commercial launch of a product. “Often these customers will apply for SBIR [small business innovation research] funding or move straight to angel or venture capital funding if the market opportunity is large enough,” said Taylor. “We support these efforts in many ways, and even though these projects often have extended timelines, have enjoyed the challenge.”

AI has not yet become a truly disruptive technology in the product design space, but the potential applications seem promising. Factors that may slow its adoption are cost, concerns over security and breach of personal data, and possible workforce reduction.

Joestgen believes generative design using AI tools can provide value when used for product design inspiration, but that risks are also involved. “Because of the limited data these AI tools use to generate designs, bias can occur,” said Joestgen. “Generated designs can also incorporate trademarked features, so designers will need to be knowledgeable about copyright liability. It is also important to note that there are different AI tools for different jobs; therefore, designers will need to have access and be proficient in multiple tools to harness their full potential.”

Another potential pitfall of relying too heavily on AI to assist with design is that all products may end up looking and operating the same.

“With human involvement,” said Dittmar, “there may be 1,000 different ways to go about solving a problem—and many may in fact work. There is probably a single best way to do something and if AI can find the most capable design, it may find the right way to solve the problem the first time—a single design, made one way, possibly by one firm, under a patented design.”

This ability to design something perfect the first time, he cautioned, would ultimately lead to a lack of innovation.

“This is because so many designs are inspired by a solution that was designed for an altogether different problem,” Dittmar said. “In some cases, it is the imperfections of a design that lead to new, different inventions. Perfection would exact a toll on the iterative and imperfect design process that makes the world engaging for innovators.” 

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Tamia Sumpter

Tamia is a driven senior undergraduate Bioengineering student currently enrolled at Clemson University. With a strong foundation in her field, she has honed her skills through hands-on experience in research and development at Eli Lilly & Company. During her time in the ADME department, Tamia contributed significantly by working on siRNAs and their applications in finding In Vitro-In Vivo Correlation (IVIVC). Looking ahead, Tamia has set her sights on a promising career in law. She aspires to specialize in Intellectual Property Law, with a particular focus on serving as in-house counsel for leading medical device or pharmaceutical companies. Her enthusiasm for this role is palpable as she prepares to embark on her legal journey! She is also a proud member of the Omicron Phi chapter of Delta Sigma Theta Sorority, Inc., PEER Mentor for Clemson PEER/WiSE, and currently serves as the President of Clemson Bioengineering Organization (CBO). With her unique blend of scientific knowledge and legal interests, Tamia is poised to make a meaningful impact in the healthcare and life sciences industries.