This technical information has been contributed by
3D Systems Corp.
Click here to find suppliers

One of These is Not Like the Other

The innerworkings (shown here) of a ‘bionic eye’ sit behind the retina and stimulate the optic nerve through 24 electrodes.
Photo courtesy of The Bionics Institute of Australia.

Patient-specific medical products stand out amongst the crowd

Rebecca Carnes
Design-2-Part Magazine “Mass customization” is a term that is an obvious contradiction — like saying a soldier was killed in “friendly fire.” Yet it is the best way to describe the future of medical technology — custom devices for the masses that are no longer one-size-fits-all.

Think custom knee implants, custom hearing aids, custom prosthetics, and custom dental implants — all individualized for a certain patient. Custom devices on a mass scale are being fueled by patients and doctors who want the same thing — for medicine to get personal.

Medical has gotten very personal for Sols, a producer of custom inserts for shoes. Instead of using a traditional cast of a patient’s foot, Sols allows each patient to scan their foot in minutes, upload the data to the company’s design center, and receive a 3D printed custom insert that fits every curve and angle of their foot.

This process allows Sols to provide its customers (the “masses”) with a high level of customization while simplifying and streamlining the production process — thus the term “mass customization.”

In the future, we will see an ever increasing number of personalized, custom products for patients, according to 3D printing industry analyst, Terry Wohlers, whose annual Wohlers Report explains new developments and trends in additive manufacturing.

“3D printing has allowed for more patient-specific care,” Wohlers said.

Medical design companies and manufacturers are quickly fulfilling the demand for patient-specific care using 3D plastic and metal printers, as well as bioprinters that can create layers of human tissue.

3D Print Me

3D printing is the driving force behind the growth of personalized medical products. Medical/ dental (13.7 %) was among the biggest industries for 3D printing in 2014, along with industrial (18.5 %), electronics (18 %), and motor vehicles (17.3 %), according to Wohlers Report 2014.

The Bionics Institute of Australia is using 3D printing technology — specifically working with a ProJet 1200 3D printer by U.S. based 3D Systems — to develop prototype implantable brain devices for projects centered on bionic eyes, hearing, and relieving epilepsy.

The institute uses 3D printing mostly for the modeling and consultation phases of development, particularly when working with surgeons about the size of the device, its contact points in the brain, and the related surgery techniques needed to implant such a device. 3D printing allows the surgeons and engineers to give input that can be translated into a relatively inexpensive model in a matter of hours or days, rather than weeks, said Robert Hilkes, public relations and fundraising manager for the Bionics Institute.

3D printing is going to create even more of a brave new world in medicine , according to experts, where a patient can not only get a new custom knee or hip printed, but possibly a 3D printed kidney, as well.

The next frontier in 3D printing for medical technology will be the printing of living tissue (referred to as “bioprinting” or regenerative medicine), where living cells are 3D printed to create a structure that is then implanted in the patient, explained Wohlers. Bioprinters construct living tissue by 3D printing successive layers of human cells onto a similar number of layers of material that make up a bio-absorbable scaffold. Cellular tissue layers are being printed, but not yet entire human organs.

“Many universities and research institutes around the world are spending impressive amounts of time and money on it,” Wohlers said. “Will we be able to print a partial or entire kidney in the future? Probably. In our lifetime? I don’t know. But that’s an exciting area to consider — that it (3D bioprinting) could lead to the printing of body parts.”

Currently, most bioprinters are in the early stages of development, but if the potential of this technology comes to fruition, these bioprinters may revolutionize the medical industry. In the near future, the Bionics Institute hopes to purchase a 3D bioprinter to build components for the bionic eye and other applications using biocompatible materials, said Hilkes.

Follow the Sign Posts

While the bioprinting of human bionic eyes and organs is still on the horizon, it shows the direction medical technology is taking for the future — with 3D printing paving the roadway.

Custom, 3D printed knee implants have already arrived on the medical scene and are gaining speed. Generally mass-produced in a limited range of sizes, off-the-shelf knee implants have resulted in many patients complaining of too much pain after surgery, as well as poor function and an unnatural feel. ConforMIS, a Bedford, Mass., medical device company which pioneered patient-specific orthopedic implants, creates custom knee implants that reflect each patient’s unique anatomy.

“The implant is manufactured to the exact specifications of the patient’s natural shape, much like a custom tailored suit,” said Philip Lang, CEO of ConforMIS, in an e-mailed response.

The iTotal® personalized total knee replacement by ConforMIS, allows for patient specific knee implants that preserve more of the patient’s natural bone unlike off-the-shelf implants.
Photo courtesy of ConforMIS.
The proprietary ConforMIS iFit Image-to-Implant® technology uses precise algorithms to convert a CT scan of the knee to a 3D model by mapping the articular surface of the joint. A precise wax mold, based on a patient’s own CT scan, is 3D printed and used to form the implant with cobalt chromium molybdenum, a standard metal used in orthopedic implants. The exactness of the implants allows surgeons to complete the procedure while preserving more of the patient’s natural bone.

“The ability to truly customize both the implant and instruments for each patient presents the potential that patients will recover faster, quickly return to normal, everyday activities, and ultimately forget they even had a knee replacement,” Lang said, adding that the procedure itself is shorter and there is also a reduced risk of blood loss.

When ConforMIS was founded in 2004, Lang said he saw the need for a knee replacement that more closely mimicked a patient’s natural knee anatomy, while correcting for deformity. The result of the customized knee implants has been higher patient satisfaction, demonstration of a more “normal feel” of the knee, and significantly reduced risk of adverse reactions, Lang said.

“Because the implant is made precisely for the unique shape and size of the patient’s natural knee, surgeons may need to remove less bone to accommodate the implant and recovery can be quicker and easier with less post-surgery pain,” Lang explained.

3D printing has enabled ConforMIS to also customize the instrumentation used by the doctors during surgery. Not only are the components (femoral and tibial implants) of the custom knee 3D printed, but also the surgical instrumentation.

Oxford Performance Materials (OPM), a leading advanced materials and 3D printing company, uses 3D printing with its proprietary technology platform and formulation of the high-performance polymer PEKK (poly-ether-ketone) material to manufacture patient-specific cranial and facial implants. A pioneer in personalized medicine, OPM became the only company to receive FDA clearance to manufacture 3D printed, patient-specific polymeric implants for its cranial prosthesis line in February, 2013. Its biomedical division received a second 510(k) for its patient-specific facial implants in July, 2014.

OPM teamed up with Yale University last October to explore a range of biomedical applications for 3D printing and PEKK. Projects include the development of new PEKK-based cranial and facial devices that support direct tissue attachment, as well as 3D printed PEKK prosthesis for rib replacement.

Fit, Feel, and Function

During a recent meeting with one of his project engineers, Tom Kramer, president of Kablooe Design in Minneapolis, reviewed six different 3D printed test prototypes for a medical device. Kramer checks early on for what he calls the three Fs — fit, feel, and function of a product.

The 3D printed prototypes allow Kramer to make the most of the design cycle, printing early concepts to be compared, as well as 3D printing final products to be tested at the end of the process.

“Without 3D printing, there would be few other options to check for fit, function, and feel. It’s so great to be able to test for those and make changes. Otherwise, you would have to make it by hand, which we did in the old days before 3D printing,” said Kramer in a phone interview. “We are feeling the prototypes with our hands because of 3D printing, and we are then able to make better informed decisions.”

Kablooe, an invention, design, and engineering firm, takes projects from concept through manufacturing. The company’s team of industrial designers, mechanical engineers, and graphic and product development specialists use a D3 Development Process that involves engineers and designers interchanging roles in order to create a holistic process that spurs innovation, Kramer explained.

Almost every project Kablooe works on involves 3D printing at some point in the process, Kramer said, adding that nearly 75 percent of the company’s creations are medical devices, including a “Nxthera” device to treat benign prostatic hyperplasia (BPH), commonly known as enlarged prostate.

3D printing is paving the way to patient-specific medical devices. The Nxthera device by Kablooe Design shoots vapor into the prostate.
Photo courtesy Kablooe Design.
Although Kablooe makes some final products via 3D printing, like the company’s custom, 3D printed “Magic Arms” prosthesis for children, the process is mostly used for research and development purposes throughout the design cycle.

Kablooe used 3D printed parts to do drop testing, impact testing, and durability testing on the Nxthera. The Nxthera device, which treats BPH in a less invasive way and with minimal side effects, won a Tekne Award last November for its innovation.

In a recent phone interview, Kramer said that the Nxthera provides a “gentle” way to reduce the prostate using steam generated through RF energy, as opposed to the traditional treatment involving burning, freezing, or cutting.

Kablooe’s task was to design a tool to inject steam vapor into the prostate, which entailed a saline flush function, a vapor delivery function, a needle deploy and retract function, a drain function, a video adapter function, and a rotation mechanism. The company had to mechanically design, invent, and discover how all these functions were going to work in a hand held tool connected to a generator unit. The Kablooe designers estimated they would need seven to ten iterations to get the design perfected and that they would have to perform product feasibility testing for the FDA.

It was not feasible to spend hundreds of thousands of dollars to make traditional injection molded tooling on early designs. And the traditional route would take up too much time as well. Kablooe turned to RedEye, an FDM 3D printing service company and division of Stratasys, to produce FDM parts with ABS plastics, saving a minimum of $250,000 and 12 weeks of time versus going to injection molded tooling and production.

Iterations were easy to handle due to the 3D printing CAD design and RedEye printing service, and Kablooe was able to easily tweak the design to a pistol-shaped grip, which it learned was preferred after gaining feedback from physicians and technicians, Kramer said.

3D Printing in the House

Orchid Design, which designs orthopedic implants such as knees, hips, spine implants, screws, and plates, produces rapid prototypes for virtually every project in-house using a Stratasys Objet30 Pro 3D printer.

The company, a product design and development division of Orchid Orthopedic Solutions, has offices in Shelton, Conn., and Memphis, Tenn., with in-house 3D printing prototype capabilities that reduce the time it takes to produce a prototype from weeks to hours.

This in-house prototyping capability has reduced the average overall product development cycle by about 20 percent. This has, in turn, driven more revenue and increased repeat business by allowing Orchid engineers to innovate rapidly while reducing cost.

The prototypes are often times used as “communication tools,” said Rob Richards, business development manager with Orchid Design’s Connecticut office, during a phone interview.

“We are able to take a design off a computer screen and put it into your hands almost immediately,” Richards said.

The shop managers in the manufacturing division inspect the prototype and advise the design engineers on how to modify the design to enhance manufacturability to lower lead times and costs, he said.

The marketing directors at Orchid Design will also show surgeons the prototype, allowing them to hold and inspect it in their hands and make recommendations for design tweaks.

“We then update the model, 3D print it again, and use it as another communication tool with the customer. Then we bring it to the shop guys and ask if there are manufacturability concerns and what they think we should change. We optimize the design and then take off to manufacturing,” Richards explained.

3D printing has also enabled Orchid Design to print parts at five to ten times their actual size in order to better analyze how they will function and then make design changes, if necessary.

“We create a lot of things for the first time; a lot of our designs have never been done before,” Richards said. “If it’s a really small part, we can make it bigger. We make a ratchet mechanism and ratchet and test whether or not our theories will work before we ever go to metal. It’s a huge experimental tool.”

The company ensures the small parts will go together in the assembly before committing to spend $100,000 or so on validation units that could take eight weeks to make and then another eight weeks to fix if it doesn’t work, he said.

For one medical project, Orchid Design used a model generated by CT scans to recreate an injury to a patient’s femur using 3D printing. This allowed them to better understand the challenges unique to the injury. 3D printing was a “huge advantage” in this case, Richards said, because the surgeon was able to evaluate the 3D printed model to make sure Orchid Design was representing the fractured femur accurately.

Orchid Design makes a point of taking the pulse on where 3D printing is heading and then stays at the forefront, Richards said.

The product at the “end of the rainbow” is when the company can scan an injury and then 3D print an implant that fits that injury perfectly, he said.

“That is getting closer,” Richards said. “But as a development company, we have to keep our eyes on trends. So when we saw things like metal 3D printers come out, we had to get one just so we could continue to be familiar and experienced with the technology. When the industry does turn in this (end-of-the-rainbow) direction, we already have our foot in the door.”