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September 25-27,2024 | SWEECC H1&H2

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Computer Concepts for Medical Device Design

Software and advanced digital tools provide developers the tools needed for extremely rapid iterations of device ideas.

Moving a traditional sketch to a computer can allow a designer to rapidly innovate on their original idea. Image courtesy of M3 Design.

Mark Crawford , Contributing Editor05.09.23

With new technologies, powerful software, better precision, more miniaturization, and greater input from healthcare clinicians, the medical device industry is turning out innovative new products at a steady pace. Whether these are next-generation legacy devices or first-in-industry, product development is booming. Devices continue to get smaller and smarter, many of them targeting the growing number of less invasive surgery applications. There is also greater focus on the total patient continuum of care. Having a great surgical device is not enough anymore—medical device manufacturers (MDMs) seek solutions that also cover preoperative planning and postoperative care. They collaborate with experienced partners that can go beyond design for manufacturing (DFM) to offer the much broader Design for X (e.g., assembly, test, usability, cleaning/maintenance, service, end of life). To achieve these goals, design firms must understand the entire desired lifecycle before considering the design of the product.

Companies are starting to rethink the design/functionality of their product offerings in considering this larger scheme. For example, MDMs are looking for procedure packs that kit multiple product SKUs into a single sterile pack. “In some cases, hospitals are looking to reduce the number of vendors and will make preference for those that can become a single-source solution,” said John Bernero, COO for M3 Design, an Austin, Texas-based product development and innovation firm that carries out design, engineering, and strategy for clients across a range of industries, including medical device companies.

The increase in outpatient procedures at ambulatory surgical centers (ASCs) has created a new type of healthcare provider/end user that is looking for streamlined products. “For example, about 20% of the instruments in a kit are necessary to perform a routine total knee procedure,” said Bernero. “If you eliminate the other 80%, not only do you save precious OR space, but you also save valuable resources that would be spent decontaminating and sterilizing unused instruments. Providing only the necessary tools helps ASCs drive their costs down and profitability up.”

There is also strong focus by both large OEMs and early-stage device companies on user-centered design early in the design cycle. “User-centered design is not just about making an aesthetically pleasing, user-friendly product,” said David Schechter, president of Meddux, a Boulder, Colo.-based provider of medical device design services and contract manufacturing for interventional, minimally-invasive surgical, and drug delivery devices. “User-centered design is the foundation for an intuitive and clear process of understanding the users and their motives and pain points, which will identify opportunities to improve the current clinical experience.”

Following this approach early in the design process helps develop products that not only meet business goals, but are also desired by the end user and encourage market adoption. User-centered design is an early investment in the future success of a device “and serves as a tool to make sure the right product is developed on the first try, which is becoming a necessity for successfully entering new markets,” Schechter added.

Current Trends

Many of the current advancements in product design are software-driven—especially tools that enable collaboration or improve efficiency, such as Onshape, which has been described as “Google Docs for CAD.” “No powerful laptops or desktops are required, just a web browser,” said Bernero. “And you can design with others on the same assembly and see changes in real time. It addresses many of the challenges of CAD file management on a single file repository.”

Artificial intelligence (AI) and generative design platforms (for example, OpenAI) allow product designers to explore more concepts in less time, speeding up the design and manufacturing process. For software developers, these tools can reduce the time required to create custom code. “We recently used OpenAI to develop a script to run a multi-variable Monte Carlo tolerance analysis in less time than our Excel spreadsheet,” said Bernero.

MDMs have long been advocates for user-centered design practices. There is a steady push to provide more enabling clinical solutions, rather than just products with features and added complexity. “Additionally,” said Schechter, “OEMs can’t afford to push forward products that do not align their brand and identity in the market. User-centered design strives to understand the clinical environment and workflow early in the design cycle so that we can provide a holistic solution that helps users and patients.”

With the recent advancements in technologies such as 3D-printed models of patient anatomy and implants, MDMs are more interested in making patient-specific devices and models. To achieve this quickly, “many companies are utilizing AI algorithms to make incredibly accurate objects in a short amount of time,” said Tessa Heydinger, director of product management for Chicago, Ill.-based Explorer, a GHX company that provides procedural playbooks and intraoperative data collection and analysis for medical device companies to improve performance and reduce procedural variability.

Virtual reality (VR) and augmented reality (AR) are gaining popularity for letting designers test concepts in a highly accurate virtual space. For example, product designers can put themselves in a mock-operating room environment from the comfort of their home office and explore product placement or test out ergonomic and usability challenges. Virtual whiteboards such as Miro have increased M3 Design’s team collaboration, speeding up the progression from idea to concept to research results. “In one space, you can place all the information you need without having to jump from file to file or application to application,” said Bernero. “This project ‘war room’ captures the evolution of the project and cuts down on the need for progress update presentations.”

As exciting, detailed, and realistic as simulations can be, they do not always provide the full picture. Viewing how the end user manipulates the product in a real-life setting enables a more human-centric design to take place. For example, surgeons may want a solution to meet their perceived perspective for a tool or device, when what is truly needed is an entirely different solution that the engineering team could have designed, had it viewed the surgeons in action. As a result, development and engineering teams are now going directly to the end user to observe live cases that will better inform clinical decisions for product designs.

“You can do as many cadaver labs with as many samples as you want, but you are never going to really capture how something is being used in a live procedure with a real patient,” said Heydinger. “Engineering teams need feedback on legacy devices, which have to be observed in the field. Being able to observe live cases and case recordings through Explorer’s digital case support solution is a fantastic way to give these teams access to the OR without the need for unnecessary travel or disruptions to their day-to-day activities. It also reduces foot traffic in the procedure suite.”

Although supply chains are slowly improving, there are still critical shortages, ranging from base resins to specialized components to packaging materials. MDMs and their contract manufacturers (CMs) are desperate to shorten lead times and accelerate time to market however they can. For example, Meddux is pushing hard to speed up the design cycle, including using rapid and iterative feedback from clinicians at each prototype step, early in the design cycle. “Rapid prototyping and 3D printing technologies are definitely enabling our design cycle,” said Schechter. “Supply chain delays for specialized components have been an issue over the past few years, but access to off-the-shelf inventory through companies like Chamfr has allowed us to keep moving. We hope for continued improvement in the supply chain this year.”

Technologies, Tools, and Time

Many of the latest technologies and tools are geared toward more efficient production and faster time to market, especially advances in additive manufacturing (AM) and AI-based design tools.

“We used to see 3D printing only being used to make basic, soft plastic prototypes, but now we are seeing fully functioning prototypes that can almost be used for validation of a design,” said Heydinger. “It is much easier to perform product equivalency testing with similar 3D-printed materials than waiting on long lead times for manufacturing production parts.”

Advancements in AM technologies and materials are reaching the level where larger-scale production of certain AM-made products will soon be viable and accepted. Leading candidates are direct metal laser sintering for metals and selective laser sintering and stereolithography (SLA) for plastics. “Meddux has recently taken some SLA-processed components through ethylene oxide sterilization and passed cytotoxicity testing (ISO 10993),” said Schechter. “The cost of these processes and the resolution is still an issue, but I do see these converging in the near future.”

Researchers continue to come out with innovative new AM technologies. For example, a new process called Continuous Liquid Interface Production (iCLIP) accelerates printing speeds by up to 10-fold over current methods and can pattern a single heterogeneous object with different resins in all Cartesian coordinates.

“In additive manufacturing, it is imperative to increase print speeds, use higher-viscosity resins, and print with multiple different resins simultaneously,” said co-inventor Gabriel Lipkowitz, an engineer at Stanford University. “Future work in extending iCLIP to new materials and geometries will focus on testing a broader range of viscous-filled resins with superior mechanical and electrical properties for applications in smart and sensor-embedded product designs.”¹

Demand for wearables is driving the need for flexible products that optimize ease-of-use, ergonomic comfort, miniaturization, and lighter-weight improvements. Flexible circuits can be encapsulated in silicone or molded to disposable medical devices that are inserted into the body. Fabrics or flexible components are ideal for body-worn accessories, such as flexible electronics embedded in athletic wear. Some companies can now expand the standard length of circuit they can produce up to 2.75 meters. For catheter applications, this expanded length is a significant breakthrough, “allowing a designer to bring fine traces all the way down the catheter shaft to enable advanced sensors or electrodes,” said Schechter. “Previously, most flex circuits were cut out of 18-inch by 24-inch panels, which are not long enough for most catheter applications.”

Computer-Based Tools and Software

A key part of DFM is finite element analysis (FEA). FEA is an essential part of robust product design—it is especially useful during DFM for de-risking designs during concept development and early-requirement-generation phases. FEA continues to evolve toward more user-friendly tools and interfaces and faster calculation methods. Due to increased calculation power, processing times are becoming shorter. Usually designers start by focusing on what is essential to device function and performance. Meddux uses a process called critical parameter management (CPM), which links critical functional requirements to critical to quality (CTQ) specifications, starting at the system level and then trickling down to sub-system, components, and manufacturing processes.

“The key here,” said Schechter, “is to focus on the critical few elements that are essential for safe and effective performance. We deduce critical functional requirements (CRFs) directly from design inputs and risk management. Once the critical functional requirements are defined, it really helps us laser target where additional attention is needed, such as detailed engineering analysis, early reliability testing, and FEA.”

AI can be combined with FEA to further refine iterations to find the very best design quickly. As AI continues to enhance FEA capabilities, FEA becomes more synonymous with virtual prototyping, where in some cases the virtual model has the potential to replace physical testing completely. In fact, depending on the application, the FDA is increasingly accepting FEA data over physical testing. Validating an FEA model requires more up-front work and investment; however, when done correctly, it saves considerable time and money in the long run.

One thing to keep in mind, cautions Bernero, is that it takes someone who knows FEA “inside and out” to produce accurate, reliable results. “If your team doesn’t have someone like that, you run the risk of producing incorrect results, which could lead to post-launch risks,” he said.

Design teams should embrace physical and open-source digital prototyping tools such as Arduino, Raspberry Pi, Figma, and others to create and test concepts. Meddux engineers utilize the latest software to predict the performance of various catheter constructs. Product development staff can baseline commercially available catheters to determine the desired stiffness, flexibility, torque response, bend radius, and other properties before they ever build the first prototype. “We then run simulations, using different material layers, braid/coil configurations, and transitions to predict performance,” said Schechter. “Typically, we are within 10% when we build the first prototype. This takes a lot of guesswork out of the equation and speeds up the development process.”

FEA and AI enable the process of generative design, which is a “strategy that augments human capabilities by using algorithms to automate your design logic,” stated AUTODESK. “You still define the design parameters, but instead of modeling one thing at a time, generative design software helps you—the designer—create many solutions simultaneously and sometimes even find ‘happy accidents’ or unanticipated and unique solutions that would be difficult to discover with traditional methods.”2

Generative design uses algorithms to create hundreds or thousands of design options for a project in a fraction of the time it takes to create a single concept using traditional methods (in fact, AUTODESK can evaluate 10,000 design options using its own generative design solution). This is the fastest way to hit the ground running with a “perfect” design and get it into the marketplace quickly. Companies that utilize generative design have reduced part costs by up to 20% and cut development time in half.³

Virtual prototyping (VP) is a design process that relies on powerful software to model a system in remarkable detail, which is then stimulated and tested by adjusting a wide variety of variables that replicate real-world operating conditions. The design is then refined by a rapid iterative process to a near-perfect state, where it will only require one or a few solid prototypes before being approved for production. VP is increasingly used as a substitute for rapid prototyping. VP draws on technical elements from digital twins, AI, FEA, generative design, and other software programs, allowing designers to create and test highly detailed and complicated virtual designs quickly. In fact, for some projects, it is possible to create a virtual prototype accurate enough that it can actually be taken to production, without the need for a physical prototype for medical device engineers to hold, examine, test, and revise.

An Innovative Future

MDMs continue to collaborate with their design partners and CMs in the earliest stages of design to create innovative devices that will be unique in the marketplace. For example, VitalStream is a wearable continuous vital monitoring device that M3 Design helped Caretaker Medical develop. “Our redesign of their fluidics subsystem freed up valuable space in the enclosure, allowing us to reduce the device’s overall form, improve the reliability of the device, and drive down manufacturing costs,” said Bernero. “The smaller footprint makes it more comfortable for patients to wear and the improved battery life means clinicians can have even more trust in the data the device is collecting.”

Explorer’s digital procedural playbooks, created in collaboration with experts and clinicians, offer detailed instruction integrated with rich media and data that contextualize each step for every role in the procedure. The playbook steps are typically navigated with a touchscreen device—however, “Explorer engineers learned that using the playbooks in the surgical field often requires a hands-free and voice-free way to advance the steps in the procedure,” said Heydinger. “To address this need, they developed the compatibility for our software to be driven by a Bluetooth foot pedal that can easily be used in the OR for a hands-free and voice-free solution.”

Minimally invasive procedures are a hot market. MDMs are coming up with designs for highly integrated devices that have embedded electronics and sensors in a single-use sterile device. Other medical applications require increasingly smaller devices that also incorporate the active steering, high torque, and force transmission needed to access a target therapy location and overlay with navigational imaging or robotic technologies.

The miniaturization of any technology makes engineering the device’s internal features much trickier. Additionally, “smaller-incision procedures will often require the use of an endoscope or surgical navigation,” said Bernero. “This presents other engineering challenges as you now are competing for space and adapting tools to be navigated while not compromising on usability or ergonomics to the user. Additionally, smaller mechanisms will be harder to pass cleaning and sterilization validations.”

Although minimally invasive procedures are amazing, there is a limit to how small a product or component can be and still be usable by a surgeon, or be effective. “The key to good product design for minimally invasive procedures is for the product to be small enough to reduce the impact to surrounding anatomy, while still exhibiting maximum coverage for the patient,” said Heydinger.

AI and machine learning will continue to speed up product design and development, especially for patient-specific devices. For example, brain-computer interface (BCI) applications have tremendous potential for transforming the medical device industry. These devices allow users to interact with computers through their brain activity—typically measured with an electroencephalogram (EEG). AI and machine learning then analyze the energy and frequency patterns of the brain, which can then be translated into energy outputs, which can enable visualizations or serve as commands to control external interfaces. BCI devices can be used to make certain diagnoses, mitigate seizures in epilepsy patients, enable precise control of prosthetics, and even power wheelchairs.

“The work related to BCI coming out of companies such as Paradromics, Blackrock Neurotech, Neuralink, and others will be game-changing,” said Bernero. “These products will not only address an underserved patient market, but also have exciting possibilities for future medical device applications.”