3D Printing: Making It Work
July 2021 Issue
On a quest to discover the rate at which additive printing is living up to its early promise in O&P and celebrating its realized potential in exciting new ways and venues, we discovered some unanticipated anomalies. Although innovation and success in the hands of early and recent adopters is documented by continuing reports and evidence, widespread integration of 3D printing technology is not as advanced—or perhaps, just not as freely discussed as one might expect.
The reluctance of sources to comment on the subject raised new questions: What's preventing additive fabrication technology from more rapid and widespread acceptance by greater numbers of leading O&P manufacturers and facilities? And what will it take to make 3D printing work for O&P suppliers, clinicians, and patients?
Each of the professionals and industry leaders we consulted—all of them demonstrably confident and adept with 3D printing technology—reminded us that it's just another tool, a different means to an end—like a typewriter and a word processor, or a bicycle and a sports car. Each will get you where you want to go—if you know how to use them.
Brent Wright, CP, BOCO, EastPoint Prosthetics & Orthotics, headquartered in Raleigh, North Carolina, and a partner in Additive America, a 3D-service company, notes that his journey toward the new technology began in 2015, driven by the waste aspect of traditional fabrication. Scanners like the Structure Sensor were becoming affordable, and since all of EastPoint's mobile clinicians maintained electronic medical records on their iPads, "this was an opportunity to put a scanner in everybody's hands," he says.
"The fact that they don't have to come back in and drop off their molds or casts saves time and decreases turnaround time: They see the patient, scan the socket, it goes into the system, we modify and print it, and it's ready to be taken to the patient. We saw it as more of a workflow issue; it bridged the gap and decreased the time between initial evaluation and delivery of an item—and resulted in better patient care."
Scans still have to be modified, he notes, but digital technology lets you do that from home instead of in the lab.
Antonio Dias, director of engineering, Hanger Fabrication Network, headquartered in Tempe, Arizona, reminds us that until recently, 3D printers were used primarily for prototyping because of the limitations of 3D-printed parts having anisotropic mechanical properties (i.e., variations in strength along different orientations, similar to wood grain). Current advancements in 3D printing technology have greatly improved the quality of materials and parts, which can be printed with isotropic properties (i.e., uniform strength in all directions), greater precision, and sufficient strength to meet the safety and functionality requirements for device fabrication customized to patient needs.
So, what's missing that should be driving the integration of 3D printing forward faster?
Garrett Harmon, applications engineering manager, Essentium, notes that through its partnership with Vorum, Essentium aims to provide a complete 3D-printing solution for clinicians, from the scanning technology to CAD/CAM software and printable files—including the additive solution as well. They've been printing sockets, KAFOs, SMOs, and more since 2011, and began offering the Essentium HSE 180 LT 3D Printing Platform to O&P clinicians in 2018.
"Building trust with clinicians who have been building O&P devices by hand for 30 or 40 years is a challenge," he admits. "It's a conversation that requires material comparisons and shared data."
For example, traditional casting methods pull heated polypropylene over the mold to make the test socket; additive methods use PCTG—a clear material with great strength—to print quickly, he explains. "We compare the mechanical properties of both materials and explain how to use PCTG while speaking polypropylene language," Harmon says.
Such knowledge fuels clearerjudgment.
Wrightnotes that multi-jet fusion (MJF) printing technology—in its fourth year of commercial availability—
is still a young technology, with a huge learning curve and only a handful of MJF printer operators in the United States who have four years' worth of experience on the job.
The machines are pricey at half a million dollars and learning proficiency in their use takes time. But, he adds, "Our payroll to keep these machines running and cover the material costs is actually the most expensive part. And if the machine is down, and you can't print, there's the added cost of outsourcing. Why would you even want to take the risk?"
He points out that as a contract service manufacturer, Additive America produces aerospace and automotive items, O&P devices, and more. By combining large and small devices in one of multiple print events, they're able to drive down the cost of each device.
Diasnotes that affordability and economics aren't the only considerations when it comes to including additive technology in your professional future. Hanger continues to examine how additive manufacturing could reduce the costs of providing prosthetic devices and contribute to positive patient outcomes, notes Dias, who suggests clinicians become well informed about device and manufacturing options, and explore any advantages that 3D printing can offer patients, above and beyond cost.
Jeff Erenstone, CPO, owner of Mountain Orthotic & Prosthetic Services, Lake Placid, New York, points out that while additive fabrication is increasingly being used in automotive, aerospace, and other types of manufacturing, traditional O&P manufacturers may be delaying the adoption or creation of 3D-printed improvements, components, or definitive versions of their products for want of an international standard.
"It's a hard nut for manufacturers to crack," he acknowledges. "There are standards that are relevant for feet and pylons, and components—but there is no ISO standard for prosthetic sockets. As newer technologies emerge, like HP's Multi Jet Fusion system, which I personally believe could make definitive devices, we have to ask, ‘How do you know how much to reinforce, how thick to make the socket, how strong it is?' if there's no actual standard that says this is truly sufficient.
"Part of the reason that we've been able to operate without one until now is that we've been doing carbon fiberglass sockets for 40 years—so we have 40 years of evidence behind us to reasonably assume that if we operate within previous parameters, it's probably going to be strong enough. Most of the time we just overbuild it, anyway. We make them extra thick and extra strong so that we know they're not going to break."
Fortunately, he points out, the American Orthotic and Prosthetic Association is actively working with the International Organization for Standardization (ISO), providing technical details to help them reach their decisions and establish the ISO standard or standards that will allow manufacturers to know the 3D-printed socket or device they are making is safe for the patient.
Meanwhile, Wright points out that they have done a lot of destructive testing for their 3D-printed definitive sockets, and after two years fitting the devices, actual patient data from their fitness trackers indicates that the users are getting four and five million
cycles from their devices. "So we feel even more confident in providing them."
Flexibility and an Open Mind
"I think what's becoming clear," Erenstone says, "is that additive fabrication is not a complete change in how we treat our patients. It's a new tool that allows us to sometimes be more efficient, sometimes achieve things in a different way, but it's not the ‘disruptor' some have called it, because it doesn't impact the core of what we do as prosthetists and orthotists.
"If I pick up a hammer or a mouse, it's still a tool, and what I'm trying to do either way is provide clinical care and get the biomechanical knowledge in my head—and the clinical oversight and even expertise—designed into the prosthesis. Using a software that essentially is geared toward sculpting things in a digital space doesn't necessarily change the way we think; we're using the same thought process—just the mouse versus the rasp."
"A tool is as effective as the one who wields it," Wright agrees. "There are times when traditional fabrication is going to make a lot more sense, especially in the heavier or maybe even in the super-active population, so I don't think it's either/or. I think it's kind of a merging of the technology into your practice, and as long as you are choosing to start learning, I think you're going to be fine, even if you're heavy on the traditional fabrication side.
"Most of the best prosthetists in the world still have yet to adopt the digital technology," he adds. "And it's because they don't have to. But they're craftsmen and they're good at their craft."
Cooper Bierscheid, chief futurist, founder, Protosthetics, Fargo, North Dakota, established his company as a central fabrication business in 2015 as a consequence of a myoelectric pediatric prosthetic arm project he began while he was studying manufacturing engineering and focused on making prostheses and orthoses more affordably.
An FDA-registered medical device manufacturer,Protostheticsworks only with O&P clinics, in close partnership with the project clinician. They offer screenshots of design modifications, involving the clinician in oversight and approval at each stage of the process. The company added 3D printing to its capabilities early on and continues to offer additive and traditional fabrication methods, and to employ the process—or combination of processes—most appropriate for each job.
And in fact, 3D-printed partial hand and finger prosthetic devices are also being used at Hanger Clinics, headquartered in Austin, Texas, in combination with traditionally manufactured components from other sources.
"New 3D-printed materials and technology are being rapidly developed," observes Dias.
"More dynamic material options create an opportunity for more of the final device to be printed and hopefully at a more cost-effective price point. The new material availability and potential reduction of printer cost could potentially be the biggest benefit for other O&P professionals.
"Traditional alignment is completed by hand on a fabrication bench by epoxying the mounting hardware to interface with the device socket. The combination of digital design with stronger 3D-printed materials allows for the mounting hardware to be printed as part of the socket. This provides precision alignment, allows us to simulate how attached componentry will function in space, and provides an overall lighter weight device," Dias says.
"When deciding which devices should be printed, we tend to focus on 3D-printing limitations and printer-specific factors such as build volume, type of printing method, and strength of the final printed device. For example, powder bed–type printers such as the HP Multi Jet Fusion become cost effective when we can fill the buildable volume with as many parts as possible. Larger devices such as lower-extremity sockets do not always fit together efficiently in build volumes and may leave a lot of open voids, which can drive up the per part cost of the print, which is why Hanger has first focused on parts that are smaller and tend to fit together better, i.e., upper-extremity devices."
Harmon observes that "most fabricators of O&P solutions are not using primarily or mostly additive—they're still using a lot of carving and handcrafting. But additive perfectly complements the bespoke nature of O&P—it's ideally designed for quick and convenient individual modifications.
"I could see manufacturers incorporating a lot more industrial machines in the future, as the size of the machines starts keeping up with O&P," Harmon says. "Right now, most don't build envelopes large enough to handle large devices like spinal orthoses, which our printers can."
Wrightis concerned that so much of the focus on 3D printing technology is on the materials and the machines that we forget about the design.
"The design is critical to success in any type of process, even traditional fabrication. If your design or plan is no good for traditional fabrication, it's going to fail. And the same is true in the digital space. For many people, it's easier to write a check for a machine than to take time to learn to actually design so that the machine will print something worthwhile."
Smaller companies, he believes, possess that passion for mastering the design aspect. "It's more than just a job for us.
"So many people get caught up on the idea of ‘I need to fabricate these devices myself,'" Wright says. "To me that's not as important as getting the fit right. If you actually concentrate on getting the inputs from the models and measurements—the shape's right, the socket fits right—and then you concentrate on making sure the device fits appropriately, who cares where it's made?"
"I think central fabrication is growing," Bierscheid observes, "as O&P is becoming more and more focused around patient care. Working with a central fabricator and utilizing the digital aspect allows clinicians to be involved in the process and provides them with oversight and control of
their carefully designed device at every stage."
A Pioneering Spirit
"The material innovation that's happened in the markets around O&P has been colossal," notesHarmon. "Now we have huge strength-to-weight ratio materials that are perfect for other applications, whether it's a definitive socket, or it's an AFO that needs to be really thin, but still be rigid. We have plenty of polymers that we can 3D print that meet those requirements, and increasingly ever more. Since most clinicians are innovators by nature, these new materials offer a rich field for their creative potential. Instead of cutting corners to innovate, they can use a tool that's made to innovate, with the innovative materials that already exist—and their ideas will flourish."
"As materials develop," Biersheid notes, "and can be printed or vacu-formed, there will be products that we've never thought of because of insurance and L-code restrictions. I think new devices made from copolyester, rigid urethanes, and Hytrel, or really advanced polyamides or nylons, will be available to solve patients' needs."
Wright points to adaptive solutions that 3D printing has made possible—static fingers for a guitarist and a device that enabled an equestrian with a transradial amputation to grip the reins. "Traditionally, we would fabricate something from aluminum bar stock and some extra epoxy; it worked but wasn't pretty. Additive fab lets us create solutions that are very elegant and functional."
After exploring a variety of 3D printing technologies, Hanger Clinic acquired HP Multi Jet Fusion 3D printing technology in February 2019. The system's capabilities were aptly demonstrated in May 2021, when a proprietary 3D-printed passive pediatric upper-limb device was fitted to a six-year-old patient named Ayden. As reported in the April 2021 issue of The O&P EDGE, the device is uniquely designed with a tensioned thumb that allows the patient to grasp, pinch, and pick up objects as their skill and adeptness improve. 3D printing was responsible for manufacturing the hardware and components fully assembled—lighter in weight, and digitally scaled for precision fit, explains Dias.
The ability for clinicians to provide diagnostic devices or make the necessary adjustments to devices to accommodate a child's rapid growth has been dramatically improved by 3D printing technology, he notes. "Such adjustments
can be made digitally and sent to the MJF 3D printer, for delivery of the modified device the next day—far more quickly than with a traditionally fabricated device."
"Kids love the cool factor of seeing their hands scanned on the screen, which engages them in the process, and hopefully contributes to successful prosthetic acceptance in the future," he adds.
An Open Mind and Willing Mentors
Harmon reflects that hands-on lessons often make believers of the intransigent; that, and the statistics Vorum reports, which demonstrate a 400-600 percent increase in efficiency after a clinic's adoption of a CAD/CAM digital workflow freed clinicians to focus more on patient care. Further increases can be achieved when using an additive manufacturing technology to complement that digital workflow.
"It makes a huge difference: All of a sudden the clinicians are doing clinic work—they're not building sockets anymore," Harmon says. "These are bespoke handmade devices that take a long time, and a lot of care goes into them. We can put the same quality and the same care with the machine without sacrificing quality, strength, or mechanical properties."
He encourages the hesitant to research the possibilities, then "just get a $300 or $400 3D printer and see what it can do. Get comfortable with it, and you'll start to see the value. If you invest a lot up front without understanding the technology, you're playing catch-up from day one. It's almost better to go with a company that has O&P applications built out or is backed by an O&P company—like us."
If help is needed, it's there for the asking, says Wright. "There are people out there in the digital space that are willing to help. They may not give you the farm or the secret sauce, but they'll get you on the right track."
"It starts with a conversation, right?" prompts Bierscheid. "We're always happy to answer questions, and there are many others you can connect with in this supportive O&P community."
Judith Philipps Otto is a freelance writer who has assisted with marketing and public relations for various clients in the O&P profession. She has been a newspaper writer and editor and has won national and international awards as a broadcast writer-producer.