OEMs Expect Suppliers to Stay Ahead of the R&D Curve
Spending time in operating rooms watching surgeons is key for design engineers.
Behind every successful medical device is a great idea—a pre R&D “ah-ha” moment. That’s the easy part—then comes the brainstorming, prototypes, trials and patents and applications. And of course the competition is putting constant pressure on surgeons and engineers alike to come up with the next great idea, faster—especially in implant markets that are getting lots of attention, such as spinal procedures.
“The landscape for innovation in this field continues to change,” said Frank W. Chan, senior director of research and technology development for Medtronic Spinal and Biologics in Memphis, Tenn. “Ten
Collaboration between engineers and surgeons is key to successful R&D efforts in orthopedic product design. Photo of Prestige Cervical Disc courtesy of Medtronic.
years ago, technological advances were primarily focused on product-based or therapeutic solutions to improve spinal fusion. While fusion is still the mainstay of clinical treatment for spinal disorders, the industry has moved to the concept of motion preservation and a more widespread recognition of the potential benefits of minimally invasive spinal procedures.”
Most new ideas come to orthopedic device designers from surgeons or other medical professionals. “No part of this cycle to develop life-saving and life-enhancing products for patients would be possible without close collaboration between engineers and surgeons,” added Chan.
“Surgeons are the primary drivers,” agreed John Pepper, founder of Creative Orthopaedics in Cheshire, Conn. “Our engineers improve their concepts and make them workable. Engineers today also need to be up on patents and manufacturing techniques, so time in the shop is invaluable for understanding the reality of machined parts versus simply dropping features in on CAD (computer-aided design).”
Successful design engineers will also be familiar with the relevant anatomy, clinical procedures and challenges and limitations of the current technology. This information is usually provided by a collaborating surgeon. “Additionally, we make efforts to observe the surgeon in clinical cases or cadaver labs,” said Stephen Santan-gelo, project leader for Orchid Ortho-pedic Solutions in Shelton, Conn. “Seeing is always better than hearing and allows for better interpretation of requirements. Also the engineers have the opportunity to experience the associated challenges and subtleties of the technique.”
Approximately half of Orchid’s clients pose problems where the solutions are generated by Orchid’s staff. “In these cases we use deliberate brainstorming techniques to generate intellectual property (IP), which we then assign to our clients,” said Santangelo. “For the remaining percentage, our customers come to us with existing IP or ideas and want us to help them with development and/or manufacturing.”
According to George Weaver, vice president of marketing for Precision Medical Products in Denver, Pa., even the greatest ideas will fail without proper marketing support. “We frequently get calls from potential clients who say they have the perfect idea that will sell itself, but they have no understanding of how to market it,” said Weaver. “Usually they don’t know the materials or how to configure the device. They might own the intellectual property rights. They think it is just a matter of building a mold and putting the product in a package. They don’t appreciate the quality or regulatory issues involved, or even how to apply for 510(k) applications. If they don’t have proper channels or buying groups, or are not seriously connected to the marketing, they won’t be successful.”
Orthopedic implant manufacturers are always looking for the grand slam—miniaturization, minimal invasiveness, outstanding patient outcomes and low cost.
“Minimal invasiveness is expected in our line of work,” said Mark Lowe, vice president of sensor business for Tekscan, Inc. in South Boston, Mass. “We manufacture very thin, flexible force sensors that can be customized into just about any shape or size, which is important for a minimally invasive system.”
Although there is a strong push by many companies to develop new minimally invasive technologies, others are trying to reduce costs in existing, proven implant and instrument systems instead of developing new ones.
Cost reductions can be achieved by incorporating common instrumentation, adjusting tolerancing and design for manufacturing.
“Additionally, “alternative manufacturing techniques are being explored. For example, companies are using rapid prototyping in the form of direct metal laser sintering to produce custom instruments,” said Santangelo.
For years, the most popular materials for large-joint implants have been stainless steel or titanium. Although these work well and are long-lasting, they are bulky, stiff and impede natural movement. Manufact-urers are now moving toward combined metal-plastic replacements. “The plastics industry has created advanced implantable resins that are FDA-approved and will last for 30 years or longer,” said Weaver. “Combined plastic and metal creates more lifelike joint action that provides a level of flexibility that was not available three to five years ago.”
New technologies in back and spine include disc implants and arthroscopic procedures for back surgery. “In the spine industry, fatigue life of the device is the biggest technical challenge,” said Pepper. “As we go from fusion to non-fusion, we are working with new materials and maximizing the materials we have. Lots of FEA (finite element analysis) always helps, too.”
For C5 Medical Werks in Grand Junction, Colo., working with advanced ceramic materials is a top design challenge. “We are developing new ceramics that are stronger, more wear-resistant, and more biologically inert and stable in the body compared to metals or plastics,” indicated Andrew Nield, director of sales and marketing for C5.
Although these materials (alumina, zirconia and zirconia-toughened alumina, for example) have been shown to work well in the human body, it still requires a good deal of time for testing and final approval by the U.S. Food and Drug Administration (FDA).
PEEK, a type of thermoplastic, is also a popular choice for implants because of its bone-like modulus and radiolucency. “Efforts for developing new coatings, surface treatments, and materials for bone in-growth, like metal foam, are also significant,” said Santangelo.
Regardless of where and how each new material is used, all biomaterials must share some basic characteristics: they must be biocompatible, have adequate mechanical properties (strength, wear, etc.) for its specific application, and be stable in situ for the expected service life of the implant. “There are standardized tests to evaluate many of these material properties, but before a given material can be deemed safe for use in an implantable device, there are also a plethora of other tests and studies that must be conducted,” said Chan. “This includes application-specific biomechanical performance tests and studies to ascertain host biological response to the material itself.”
Testing and Approval
Medical devices go through four development stages: concept, feasibility, verification and validation. Once a concept is selected, it is evaluated for feasibility. The feasibility stage yields a device that functions like, but does not necessarily resemble, the final product. “Feasibility testing then evaluates the device against the design requirements and early stage risk analysis,” said Santangelo. “This level of testing often mimics verification testing.”
“By its very nature, product development is an iterative process,” added Chan. “Throughout the process, design optimization is achieved progressively by using combinations of engineering principles, computational analyses, and physical product testing (as well as clinical insight from the end users of these products). Each performance evaluation stage gate makes up the real-time feedback loop in the design optimization process. This process is robust, and generally by the time we conduct the final design verification and validation testing, the pre-established acceptance criteria are achieved.”
From a mechanical testing perspective, it is not uncommon to go through three or more design iterations before the acceptance criteria are achieved. The process of refining the design can be painstaking at times. “As you address one failure mode, the next round of testing may uncover a different failure mode that you have created through your design change,” said Kevin Knight, president of Knight Mechanical Testing in Fort Wayne, Ind. “It is a difficult challenge to balance efficacy, ease of use, manufacturability, and cost to create a product that meets the performance standards set forth by the FDA.”
The testing process is rigorous and time-consuming; however, proper prep-aration prior to testing can often save considerable time and money. “The most successful designs that we see generally come from companies or individuals who have done a proper risk analysis or dFMEA, and have identified potential failure modes through FEA,” said Knight. The FDA generally requires that the “worst case construct” be tested so DFMEA (design failure effects analysis) and FEA can help identify the size, orientation, or version of the device that is most likely to fail.
The point of the testing process is for the prototypes to ultimately fail. “Many times we work with customers who don’t realize that fractures are necessary to complete the test,” continued Knight. “The most common method for evaluating the fatigue life of an implant is the development of an SN curve. The FDA generally requires a minimum of six implants tested to failure at different loads. Using the point of failure at each of the loads, a plot known as the SN curve can be constructed to describe the endurance properties of the device under test. Many customers are under the impression that the test is a ‘pass/fail’ situation where if the implant breaks, it fails the test. While pass/fail testing can sometimes answer the question ‘is it good enough?’ the SN curve is a valuable piece of information to the development engineer and the reviewer because it can answer the question, ‘How good is it?’”
Validation is the last step in the evaluation process and determines if the device meets the user requirements. It is critical that validation be performed by someone other than the engineer on the project and is preferably the end user. “Validation testing should be carried out in an environment as close to the actual environment as possible. For orthopedic medical devices, this is often in a cadaver lab,” said Santangelo.
As the complexity of medical devices increases, the more extensive the process of product testing becomes. The process can include tests that have been standardized throughout the medical device industry for many years—those tests whose specifications have been established by national and international standards committees. “The process can also include those tests that need to be custom-designed to evaluate the performance of more unique products in the most clinically-relevant, in-vitro configurations possible in order to subject the devices to conditions they would see when implanted in a patient,” said Chan.
Sometimes, product testing is extended to include animal models in order to evaluate aspects of design features that must be subjected to a live physiological environment. Whatever the scope of testing required for a specific product, each test must be rigorously designed and conducted to take into account how the product may be used and the specific set of boundary conditions that it will be subjected to in the patient.
Speed to Market
Time to market varies widely based on technical risk and complexity. “The 510(k) process generally require about six months just for clearance,” stated Santangelo. “Depending on the complexity of the device or system, development (on average) can take six to 12 months. However, utilizing CAD with our onsite rapid prototyping and CNC fabrication facility, we have turned napkin-sketch concepts into functional prototypes within days.”
“The increasing demand for quick turnaround is driving more business to vendors and component manufacturers who can handle most, if not all, the steps in the process,” said Weaver.
“A ‘one-stop shop has everything under one roof and can control all the manufacturing design, tooling, and validations. That’s a big advantage. We can turnkey some products in a month or two—more complex products, such as devices that are sterilized and packaged in house, may take a year or more.”
Precision Medical Products continues to expand its capabilities. When it didn’t have the right equipment for manufacturing a back implant, the company invested in
a laser welder for $200,000 and a laser-etching machine for $100,000. “We realized during the initial R&D we would need this capacity so we invested in the equipment,” said Weaver. “And now we can offer this advanced technology to other clients.”
And Weaver’s staying busy—with clients in drug delivery, orthopedics, ophthalmology, dental, diabetes, and cardiovascular, he’s manufacturing on three shifts seven days a week. “For January-February of 2009, we have never been this busy as far as quoting,” he said. “There are many quoting opportunities during this downturn in the economy.”
A Simpler Supply Chain
To reduce risk, reduce cost, and improve quality, many OEMs are taking a serious look at their supply chain and shedding suppliers. For example, some molded parts might come from suppliers in Mexico or Asia; packaging might come from Canada or Europe. The number of vendors and suppliers contributing to a particular device might be as high as 75 or more.
“OEMs are starting to realize that having too many suppliers is not cost-efficient,” said Weaver. “If there is a problem, it is a time-consuming and costly investigative procedure. With only a few key suppliers, R&D and quality control for the whole process are much easier to track and manage.”
Collaborating with suppliers at a more-critical product development level is one way medical OEMs of all types and sizes can successfully battle competitive pressures and remain technologically relevant in the future.“An increasing number of medical OEMs are forging longer-term collaborative relationships with preferred component suppliers because of the need for ultra-reliable products,” agreed Jim Sittler, vice president of global sales and marketing for Bal Seal Engineering in Foothill Ranch, Calif.
“Early-stage collaboration between an OEM and a component provider can push technology forward—and not just for a specific device model or manufacturer, but for a whole product type. With these kinds of partnerships, you can intensely focus the resources of two or more organizations on an area of functionality or design. And in many cases, what you end up with is a game-changing solution, a whole that’s greater than the sum of its parts.”
NuVasive, a San Diego, Calif.-based manufacturer of products for spine disorders, wanted to enhance its cervical plate by integrating a locking system to prevent screw fasteners from shifting or backing out over time.
NuVasive teamed up with Bal Seal Engineering to create the Helix anterior cervical plating system in 2007. After significant prototyping and testing, they successfully released the breakthrough locking system that makes fasteners more resistant to axial and torsional loads.
“The establishment of an innovative partnership at the front end of the project was absolutely critical to its success,” said NuVasive marketing director Caleb Granger. “Component suppliers have seen such a broad range of applications and issues—why wouldn’t a manufacturer want to tap that experience and leverage it to create truly unique, differentiating technology in its market space?”
Mark Crawford is a full-time freelance writer based in Madison, Wis. He writes feature articles for a variety of regional and national publications and is the author of five books.