At formnext 2017, Stratasys introduced a new piece of software, GrabCAD Voxel Print, which complements its PolyJet technology with a new level of control over the materials with which printers like the full-color, multi-material J750 printer. Now, the company has demonstrated just what sort of practical applications the technology offers by announcing a new medical 3D printing product called BioMimics.
GrabCAD Voxel Print
Stratasys’ PolyJet technology is capable of melding photopolymers and inks in such a way as to create a broad range of colors and materials. The latest PolyJet machine, the J750, can print up to 360,000 colors from up to six different materials at once, including varying levels of translucence, stiffness and flexibility.
What GrabCAD Voxel Print brings to the table is control over these material and color combinations at the voxel (3D pixel) level. It’s now possible for J750 users to add a new level of detail to the technology, as well as complex microstructures and textures. By altering the microstructure of a 3D-printed object, the overall physical properties and macrostructure are changed as well.
While the software’s applications are fairly obvious when it comes to the visual arts—LAIKA, the animation studio behind ParaNorman, is using the technology in house to produce facial animation in its films—the announcement of BioMimics takes the technology’s possibilities into a potentially more critical space.
BioMimics
Stratasys Direct Manufacturing has now launched its BioMimics software as a service (SaaS), which allows medical professionals and businesses to 3D print extremely detailed and lifelike models for applications such as training and medical device development and testing. To start, these models include bone and heart tissues, with vascular structures to be available in the first quarter of 2018.
What makes these models so unique is the ability of GrabCAD Voxel Print to design microstructures that reflect the tissues that make up the human body and the capability of the J750 to reproduce those structures from a variety of materials as a 3D-printed model.
Scott Rader explained that, until now, STL files, the standard format for 3D printable models, have been printed in a manner that sees the outer shell of an object printed in detail, while the interior is filled with a monolithic material. While it’s possible to vary the interior structure to an extent, printing lattices and hexagons to increase flexibility and reduce material, Stratasys has worked with medical experts to create interior patterns that reflect the microstructures of human tissue. These varying microstructures and their accompanying photopolymer materials are being called BioMimics Building Blocks (BBBs).
“The human body is made up of a series of microscopic architectures which are built up to create our bodies,” Rader said.“Take a look at our bones. Our bones are not a single, solid material. They have an outer shell, which is called cortical bone, an inner shell, called spongy or cancellous bone, and then on the interior made of marrow. When you define something as an STL, it’s been very difficult, if not impossible, previously to really define the model as a unique series of microstructures that build up a macrostructure that replicates the form and function of a part of the human body.”
“If you’re putting a pedicle screw into a spine, you don’t actually put the screw in into a solid block of material. With BioMimics, we’re able to replicate the real-life structure of the spine,” Rader explained.
For femurs or other long bones in the body, another BBB, marrow, is surrounded by the spongy bone BBB, which is surrounded by a hard, cortical BBB. Altogether, the BioMimics Creation Suite has 87 different parameters.
“We can actually adjust the thickness of the cortical shell,” Rader explained. “A patient with osteoporotic bone has difference in the thickness of the cortical bone and in the size of the pores of the spongey bone compared with a young patient with healthy bone. We can vary those textures so that, if you’re designing a product for patients with osteoporotic bone, we can replicate that faithfully. The same idea extends to hearts and pathologies of the heart.”
BioMimics in Practice
The first two markets Stratasys is targeting is medical training, from med students all the way up to attending physicians, and medical device manufacturing. Med students, for example, can diagnose pathologies from 3D-printed models or even train for surgery.
Shi-Joon Yoo, MD, PhD, cardiac radiologist at the Hospital for Sick Children and professor of Medical Imaging and Pediatrics at University of Toronto, explained in a press release how the technology can be used for training purposes, “As one of the top research and pediatrics hospitals in Canada, SickKids is committed to unprecedented innovation to positively impact the well-being of children around the world. We have developed new training programs through 3D printing that allow surgeons to practice procedures on replicas of real patient’s pathology. BioMimics enhances the realism and clinical validity of the models even further—allowing the surgeons to develop the techniques and skills that will translate into live patient cases.”
Device manufacturers can iterate designs on models that actually replicate the real anatomy that the device is designed for.
Dr. Adnan Siddiqui, chief medical officer at Jacobs Institute, vice-chairman and professor of Neurosurgery at University of Buffalo Neurosurgery, said in the same press release, “The BioMimics capabilities Stratasys has now developed enable a level of biomechanical realism and clinical sophistication not previously available in any vascular model. BioMimics will enhance medical innovation in vascular disease by enabling improved pre-clinical validation of new devices and clinically realistic training simulators.”
Mike Gaisford of Stratasys emphasized that this technology not only helps medical professionals, who may regularly see such biological structures, but also engineers who are working with those professionals to create devices. “When some of these engineers get their hands on 3D-printed models, this is the first time they’ve deployed their device in a clinically realistic environment. It really breaks down the barriers to performing the testing, training and understanding the anatomy. They’ve said, ‘Oh this is what the doctors are talking about when they’re describing the anatomy,’ ” Gaisford said.
This, according to Gaisford, is key to accelerating product development and deployment. “It’s going to drive a lot more acceptability to testing on realistic platforms as a company is developing a medical device. No longer will an engineer have to wait two months and schedule an animal study to be able to deploy the device onto a clinically relevant model,” he said.
Research institutes, medical schools and device manufacturers can go to Stratasys Direct Manufacturing to purchase products at varying levels of customization. The first level consists of off-the-shelf models of bones, such as parts of the spine or long bones like the wrist and femur, and heart tissue.
The second level allows these customers to come to Stratasys with their own models, and the company will use these already validated BBBs and apply them to the model, quickly creating a more specific model for a certain pathology or patient demographic.
For instance, a company designing a plate for correctly aligning wrist bones that have been damaged could order a 3D-printed model of a healthy wrist bone from Stratasys, but they could also send a wrist model created from a CT scan of an older patient with osteoporosis. The BBB for osteoporotic bone would be quickly applied to the new file and a new model could be printed, allowing the manufacturer to design plates for both young patients, who may break wrists in skateboarding falls, and older patients, who can suffer from osteoporosis-related wrist fractures after falls.
Finally, the third level is total customization, in which customers can have completely new BBBs and models created by Stratasys, such as the gastrointestinal track, on an as-needed basis.
3D Printing in Medicine Today
Ultimately, Stratasys believes that BioMimics could be used for procedural planning of patient-specific surgeries, but that it will first need to validate off-the-shelf and custom models in pre clinical settings. Currently, however, “the tools and the service will not be fulfilled in that golden window of time to enable this for procedural planning at the start,” Rader said.
Stratasys isn’t the only company tackling this space. Arguably, the leader in medical 3D printing may be Materialise, which both has a suite of software tools for medical 3D printing and offers engineering and 3D printing services for the medical sector. The company employs engineers who are capable of working with medical professionals to create custom 3D-printed parts for surgery rehearsal, education, implantation and research. If the BioMimics Creation Suite is made available to PolyJet customers, Materialise could likely deploy that solution as well.
3D Systems is also increasing its efforts in medicine, with CEO Vyomesh Joshi modeling the rest of the company’s verticals after its healthcare unit, which he sees as the most successful. At its Healthcare Technology Center in Colorado, the company employs biomedical engineers to aid in the manufacturing of 3D-printed osteogenerative(non-patient-specific) implants, patient-specific presurgical models, and patient-specific surgical tools.
Rader said that Stratasys does not have biomedical engineers working within Stratasys, but has a “universe of partners” that can aid in engineering patient-specific models for its customers, such as converting patient CT scans into 3D-printable models. 3D Systems also does not have the ability to create models as detailed and lifelike as those that can be made with the J750 and GrabCAD Voxel Print.
According to market research firm Gartner, the medical industry is at the forefront of 3D printing adoption. Applications include custom surgical tools, such as drill guides; osteogenerative bone implants, which are made using a unique microstructure that encourages bone growth; presurgical planning models, made from patient CT scans to better prepare for an intensive surgery; custom prosthetics; and the applications that Stratasys is tackling with BioMimics.
Currently, Gartner has medical 3D printing situated at the “Trough of Disillusionment” in its Hype Cycle. This means that we’ve already been disappointed by previous medical announcements (3D-printed liver anyone?), and are now managing our expectations. Developments that occur from here on out may be expected to be truly practical and realistic. BioMimics definitely fits this characterization.