Jeff Kapec07.28.10
Using digital manufacturing, makers of orthopedic implants can produce small, detailed parts such as the ones shown above. The nickel is provided to demonstrate scale. Image courtesy of Tanaka Kapec Design Group, Inc. |
That perception is starting to change and for good reason. Advances in EBM and DMSL processes have eliminated the drawbacks and, as a result, created the potential to transform the production of orthopedic implants and instruments for the benefit of the industry and patients alike.
For decades, industries such as aerospace have been producing high-performance parts in small volumes by fusing metal, ceramic or other particles using heat and/or pressure. But although the orthopedic industry also has a need for high-performance parts that can be cost-effectively produced in low volumes, digital manufacturing—also called additive manufacturing—has not been adopted widely.
Electron beam melting, which as the name suggests uses an electron beam as the energy source, and direct metal laser sintering machines, which use a laser as the energy source, have improved considerably in recent years. Medical device manufacturers now can digitally manufacture final products using the same materials they use in their existing casting and injection-molding processes. In recent years, the ability to produce metal components with sufficiently smooth surfaces has increased greatly. Much of the current research is focused on introducing a broader range of materials for use in digitally manufactured implants and implant devices.
The properties of digitally manufactured devices and implants have improved to the point that they now are on par with many parts produced using traditional methods such as metal casting.European regulators currently allow the use of digital manufacturing for implants and implant devices. In the United States, implant instruments digitally can be manufactured. Concerning implants, the U.S. Food and Drug Administration still is considering whether to approve the materials being used in the digital manufacturing process.
Enable New Business Models
With the technical obstacles largely overcome, the makers of orthopedic implants and implant tools have an opportunity to radically re-think their production processes and, in some instances, their entire business model.
For executives, engineers and designers serving the orthopedic device and implant industry, adopting digital manufacturing can be difficult, both financially and intellectually. Companies that have invested heavily in traditional casting and injection-molding production processes must make a major financial commitment to add digital manufacturing to their current operations or make a complete transition out of traditional manufacturing. Making the change requires more than a financial leap of faith. It also requires abandoning some or all of the thought processes developed building a successful business based on casting or injection molding. For orthopedic industry manufacturers, it may be a leap well worth taking.
A New Design and Manufacturing Paradigm
Digital manufacturing can eliminate several time-consuming and expensive steps in the design and manufacturing processes for orthopedic implants and tools. With digital manufacturing, you can move directly from a computer-generated design into the manufacturing process, changing the role of prototype testing, and tooling in the overall product development process. For example, simply eliminating the need to invest in tooling for a specific part can save $75,000 or more and make it financially possible to produce short production runs of only a few hundred units.
By changing the cost structure for short production runs, orthopedic device companies can afford to pursue more creative and innovative designs that might have been too risky if a major investment in tooling for injection molding or casting production was required to determine marketplace viability. One executive at an orthopedic device company recently explained that his company had begun using digital manufacturing to develop innovative new products in quantities of 500 so surgeons can work with multiple functioning prototypes rather than non-functioning versions that they only could hold in their hands.The faster timeline and dramatically lower costs enabled by digital manufacturing are inspiring the company’s engineers and designers to explore and develop new creative approaches in design for surgeons to validate.
The ability to input 3-D computer solid models directly into an EBM or DMLS machine also makes it possible to more rapidly and cost effectively evolve a product. In a matter of weeks, several iterative versions of a design can be produced and delivered to the field so users can try them out, provide feedback, and then the design can be refined based on this feedback.
Enhanced Product Quality
The benefits of digital manufacturing extend beyond the production processes to the end product. The quality, precision (to within tolerances of 0.001 of an inch), simplicity, and versatility of the implants and implant instruments themselves can be enhanced. It’s possible with digital manufacturing to make one complex part that, with classic manufacturing, would need to be an assembly of several smaller parts. For example, in creating complex implants such as artificial hips or elbows, the number of distinct components can be significantly reduced by creating independent parts within another part. For use in other joints, it soon may be possible to create two interlocking parts that don’t have a joint by setting up the production so each part is built around the other.
Digital manufacturing also is creating the first realistic opportunity for mass customization in the orthopedic implant industry. Implants customized for an individual can be created quickly and cost effectively by using information captured in an MRI (magnetic resonance imaging) procedure to create an implant that fits perfectly with a patient’s anatomy. This can be useful, particularly in surgeries to correct a deformity or that work within the constraints of a deformity.
Improve the Implant Procedure for Surgeons
With digital manufacturing, the device company can benefit, the patient can benefit and so can the surgeon. By creating implants to conform to the unique shapes of individual patients, orthopedic surgeons can complete a procedure without making nearly as many adjustments to the implant and to patient’s anatomy during the operation. I once observed a spinal surgery on a sclerosis patient where the surgeon, using a traditional implant, had to bend the rods to make them fit the patient’s anatomy. If the surgeon was using a pre-engineered, custom-fitting part, he still would have had to make adjustments during the procedure, but the process would have been much simpler and easier.
The MRI information used to create a custom-fitting implant also can be used to give the surgeon a drill guide for use in drilling into the bones to attach the implant.
A Positive Personal Experience
DMLS technology recently was used to to help Stryker Corp. create multiple experimental prototypes for delivering materials that facilitate cell growth. As part of the project, my firm was required to design and build prototypes for intricate grasping jaws in a very short time frame. At first, we approached a number of Swiss screw machine shops and other precision CNC houses to get the part built. Some said they couldn’t do the project for technical reasons. Others said they could do it, but the cost and the turnaround time would have been unacceptable.
This prompted us to contact a DMLS sales rep and present the challenge to him. Almost on the spot, he said, “Yes, we can build this.” Within two weeks we had created four completely different, workable designs that were ready for trials by surgeons in cadaver labs. The parts created using DMLS were dimensionally precise. They simplified the design because multiple features were combined into one part and required no secondary finishing other than removing support posts. Because they were made from surgical-grade stainless steel, the same material that would have been used in traditional manufacturing, they had the same strength and durability.
For Stryker, using DMLS technology meant they had four options for surgeons to consider instead of one or two and they had them in working form several weeks sooner than would have been possible using a traditional approach.
Given the current market forces impacting the medical device sector, digital manufacturing has the potential to significantly improve patient care, reduce healthcare and manufacturing costs and decrease time to market. How often does a win-win like that happen?
Jeffrey Kapec is a principal and executive vice president of Tanaka Kapec Design Group, Inc.From 1980 to present, Kapec has worked on design and product development programs in the following areas: surgical instruments, medical diagnostic equipment, pharmaceutical packaging, drug delivery systems, technical instruments, office equipment, office furniture design and consumer products. He has been awarded more than 30 utility and design national and international patents in advanced technology, surgical instruments, and mechanical design. Kapec has logged hundreds of hours viewing and recording surgical procedures with some of the most renowned surgeons.