Outsize medical “miracles” can come in very small packages. In Ann Arbor, Michigan, a team of doctors and engineers saved an infant and a toddler in the last two years by inventing and implanting tiny expandable splints that hold their damaged airways open. Last Christmas in São Paulo, Brazil, an engineer and his daughters assembled and donated small artificial hands made out of plastic for children who couldn’t buy prosthetics.
On the other side of the world in China last year, an orthopedics professor created a rotating neck bone to replace a cancerous one in a young man’s spine. The artificial axis, which was made of powdered titanium and had no screws, was a perfect match. And in Stuttgart, Germany, an international team of experts invented a new micro-robot that is as wide as three human hairs and can swim through body fluids to deliver drugs.
What do these astonishments have in common? They were all the result of 3-D printing, a process by which successive layers of material are sprayed out to produce three-dimensional objects from a computer program. In each case, the life-saving or life-enhancing device was crafted on a printer.
Invented in the 1980s to make working models or “prototypes” for industrial manufacturing and researchers, this revolutionary technology uses special printers — either consumer-oriented desktop models or commercial ones — to spew out three-dimensional objects that range from trinkets and jewelry, to machine parts and body parts, to food for astronauts and, perhaps most controversially, guns. Computers guide the process, which often only requires a few hours and uses materials such as melted plastics, powders, metals, squishy concrete or even human tissue.
“Imagine an ink jet printer that, rather than spraying out ink in the shape of letters, sprays out a plastic or metal gel or powder in the shape of a tooth, finger or a hip joint,” WebMD’s Sonya Collins explained in a special July 2014 report. “A typical printer receives a document to print, while 3-D printers take their commands from an MRI or a CT scan of a body part. Also known as ‘additive manufacturing,’ 3-D printing produces an object, layer by layer, from the ground up.”
Business for 3-D printing in general is booming, and medical applications are one area fueling this global growth.
According to Lux Research, the 3-D printing market as a whole should nearly quadruple to an estimated $12 billion in 2025, led by automotive, medical and aerospace industries.
Medical devices taking advantage of the 3-D growth include prosthetics, where traditional artificial limbs costing thousands or tens of thousands of dollars can sometimes be replaced by a simple, 3-D printed model that can be had for $50 or, for something more sophisticated, under $1,000. In addition to being more affordable, 3-D-printed prosthetics can also be more comfortable — even more stylish — than their traditional ill-fitting counterparts. While printed prosthetics raise safety and regulatory concerns, they have dramatically changed the landscape of limb loss.
Other external medical devices such as dental fixtures, hearing aids and even back braces are also part of the current 3-D printing mix. For example, Invisalign orthodontic braces, the clear, customized alternative to clunky metal braces, was made possible by 3-D printing. More stunning is the groundbreaking device invented at the University of Michigan that saved two infant lives with 3-D-printed splints inserted into their windpipes to hold their airways open, as first reported by the New England Journal of Medicine in 2013. The custom-designed splints are made of a biopolymer that is absorbed by the body over time.
And then there are medical tools, some of them prosaic, such as a 3-D-printed suturing device with safety features. Others are more exotic, such as parts to replace fractured skulls, cheekbones and eye sockets. Likewise, the micro-robot invented by the international team in Stuttgart sounds as if it came out of the pages of a science-fiction novel.
The tiny robot has the novel ability to swim like a scallop, opening and closing to move through liquids in the human body, including blood, joint and eye fluids, in order to deliver medicine to the body. Controlled by external magnets, the robot could be particularly useful in treating eye disease with drugs, said one of its key developers, Tian Qui, in an email to The Diplomat.
The originator of the project and its team leader, Peer Fischer, told us that the little robot “opens up entirely new possibilities in designing and operating untethered micro devices” for medical uses inside the human body.
Another fascinating area of growth is 3-D-printed models of the human body, from the simple to the sophisticated, that are appearing in classrooms and operating rooms. Created from a patient’s CT scans or other imagery, 3-D maps can help surgeons practice on a body part before actually going in for a complicated procedure. Nicholas Giovinco, a professor of surgery who specializes in lower limb disorders at the University of Arizona, said in an interview that he uses 3-D-printed materials resembling bone to create replicas of a patient’s foot for surgery rehearsals. Living 3-D-printed tissue could also help pharmaceutical companies test out drugs and vaccines.
The field has grown so important that the National Institutes of Health has created an online public library of open-source medical models that includes biological entities large and small, from miniscule molecular structures to major body parts.
Another area that has piqued hopes and interest is the 3-D printing of body parts and tissues for human implants, although the field is in its infancy and largely experimental. One of the most exciting and eyebrow-raising developments in 3-D printing is tissue printing or “bioprinting,” a field that one day may be able to print and implant entire human organs such as a heart or a liver, or at least enough of one to permit continued functioning and extend life.
But the elusive Holy Grail of developing a human organ is the subject of fierce debate. “For years, researchers have dreamed of engineering kidneys, livers, and other organs and tissues in the lab, so that a patient who needs a transplant doesn’t have to search for a donor,” wrote the New Yorker’s Jerome Groopman in “Print Thyself” last November. “But growing usable tissue in the lab is notoriously difficult; the advent of 3-D printers that can print ink made of cells has offered a ray of hope.”
One of the most advanced techniques developed so far involves artificial bone and bone substitutes, such as the printing in China of a vertebra to replace a cancerous one.
The possibilities are intriguing companies around the world. In Vietnam, 3-D-printed jaw bones are being provided to hospitals by the country’s leading printer company, 3DMaker. In the state of Connecticut here in the U.S., Oxford Performance Materials is offering orthopedic implants made of its patented materials that are printed from CT or MRI scans to replace missing or diseased bones in the skull, as well as elements in legs and feet.
Beyond being an emerging capitalist enterprise, 3-D printing is also ushering in a quiet social revolution as a democratizing breakthrough that benefits the average consumer — and patient.
Many of the computed-aided designs used in 3-D printing are, in fact, open-source material — i.e. available on the internet, downloadable and free. Partly because desktop 3-D printers are relatively inexpensive — $300 to $3,000 — grassroots, do-it-yourself “3-D maker” communities, as they call themselves, have emerged and morphed into charitable endeavors and new research models, most of them in medicine.
Professor Joshua Pearce of Michigan Tech is an open-source advocate and the author of “Open-Source Lab: How to Build Your Own Hardware and Reduce Research Costs.” He argues that 3-D printing technologies “promise previously unheard-of access to sophisticated instrumentation by … laboratories in underdeveloped and developing countries.” Such access will accelerate science worldwide, he argues.
Similarly, the nonprofit Open BioMedical Initiative and the startup Sharebot, both based in Italy, have partnered to use 3-D printing and open-source software to create and disseminate not only low-cost prosthetic hands, but also medical technologies such as microscopes to hospitals in developing countries worldwide.
Perhaps the largest and most influential group in the 3-D maker culture is the e-NABLE nonprofit. It grew out of a collaboration between Ivan Owen, an American inventor and entrepreneur, and South African Richard Van As. The two, supported by printer manufacturer MakerBot, invented an inexpensive, plastic, 3-D-printed “Robohand” to replace fingers Van As had lost in an accident. They also donated one to a small child, made their design openly accessible online and soon a charitable movement was born.
E-NABLE describes itself as “a global community collaborating to make free 3D printed prosthetic hands available to all who need them.” Jon Schull, a professor and research scientist at the Rochester Institute of Technology in New York, dreamed up the idea of putting e-NABLE participants together on a world map in cyberspace. In 2012, he said “five or 10 people signed up” to put a pin on the map if they needed a prosthetic hand or if they had access to a 3-D printer and were willing to make one as a volunteer.
By December 2014, the map had 3,200 pins on it. Volunteers around the world have 3-D printed, assembled and donated more than 700 prosthetic limbs, most of them hands for children without the resources for traditional prosthetics, which cost thousands of dollars.
Schull describes e-NABLE as “a global volunteer network built on an infrastructure of electronic communication, 3-D printing and goodwill.” An evolutionary biologist, Schull told us he was surprised that the site’s map and videos had gone viral. He linked it to his own theoretical work on the collective intelligence of evolving populations, calling e-NABLE “a primal soup of innovation and creativity.”
For example, Filipe Wiltgen, an engineer in São Paulo, is the e-NABLE volunteer who printed and assembled 3-D prosthetic hands last Christmas. His helpers, daughters Rafaela and Carolina, drew a multiethnic map that shows children hand in hand around the globe wearing 3-D-printed prosthetics.
Another Brazilian, Marcelo Botelho, also created hands through the nonprofit, including one for a São Paulo child who had asked for money on the streets. Botelho now aims to get more 3-D printers and trained local users into Brazilian communities that need help with low-cost prosthetics.
Dr. Albert Chi, a trauma surgeon and professor with Johns Hopkins Medicine, has facilitated e-NABLE meetings and calls its open-source, collaborative model a “humanitarian technology.”
But like any pioneering technology, 3-D printing has its drawbacks — and dangers, as illustrated by the debate over whether people can print handguns at home. Moral, ethical and simple feasibility and cost questions also plague the burgeoning industry. And major advances such as 3-D-printed organs are still years, if not decades, away.
But the 3-D renaissance is already touching many lives, and may be the future of fields such as prosthetics. Chi has turned to the technology to make prosthetic limbs cheap, widely available and relatively simple. After reading a Baltimore Sun story about how Chi built a glow-in-the-dark artificial hand for a 5-year-old boy, a group of fifth-grade students in Maryland sent letters asking if the Johns Hopkins surgeon could build a hand for their teacher, who had lost hers in an accident as a teenager. Chi agreed, and even enlisted his wife to paint a zebra pattern on the hand, which the teacher had requested. He told the Morning Call newspaper that “receiving those letters has to be one of the highlights of my entire career.”
About the Author
Gina Shaw is the medical writer for The Washington Diplomat.