3D printing grows up
By Matt Nixon
Scott Hollister is a professor of biomedical engineering and mechanical engineering and associate professor of surgery at U-M. When I first spoke with him, he had been part of a what was already shaping up to be a victory of engineering. But no one within the university system could go public with some stunning information: 3D printing had been used to save baby Kaiba Gionfriddo's life.
"Kaiba's case is definitely the highlight of my career so far. To actually build something that a surgeon can use to save a person's life? It's a tremendous feeling."
For over a year Hollister was under a publicity embargo. Outside of the U-M system he was forbidden to speak officially about the procedure. The New England Journal of Medicine's review process required a year's worth of proof before the article could be published.
However, for the mother of a (forgive the fitting cliché) miracle child, she was on board from the moment that this unique opportunity presented itself. "Quite a few doctors said he had a good chance of not leaving the hospital alive," says April Gionfriddo, about her son, Kaiba. "At that point, we were desperate. Anything that would work, we would take it and run with it."
Tracheobronchomalacia is an appropriately ugly word for a rare and potentially deadly disease. It creates a malformed bronchus in its victims. The result is an air passage that is too narrow to allow for proper respiration. And in Kaiba's case it was literally suffocating him.
Hollister and his colleague, surgeon Glenn Green, M.D., and associate professor of pediatric otolaryngology at the University of Michigan obtained emergency clearance from the Food and Drug Administration in order to create and implant a tracheal splint for Kaiba. It was fabricated from a biopolymer called polycaprolactone.
"The material we used is a nice choice for this. It takes about two to three years for the trachea to remodel and grow into a healthy state, and that's about how long this material will take to dissolve into the body," says Hollister.
At the basic level, 3D printing is a process wherein a digital model of an object is made physical either by building up layers of a substrate (using a nozzle) or by removing layers from an un-sculpted chunk of material via laser. Once fabricated, the resulting sculpture can be used to replace, theoretically, any body part.
For example, Hollister has had success recreating segments of the human jaw and other regions of the skull. When it comes to these procedures, he works with a surgeon and uses a CT scan of the defective bit they wish to recreate. Once he has built up a digital model, the information is fed into the 3D printer. At the U-M Biomedical Engineering (BME) labs, the printer we're talking about is roughly the size of an industrial refrigerator. It has a big bubble window so that you can watch as the digital robotic sculptor removes what doesn't belong.
Hollister says we can conceivably print any part of the human anatomy. However, making the part work is a different story. For the time being, bones and cartilage are the most common pieces being swapped out. Hollister and company have done it before -- lots of times.
Green from the medical school and Hollister from Michigan Engineering teamed to design, create and implant a splint that was placed over Kaiba's malformed bronchus. The splint successfully pulled open the passage and his little lungs filled with air immediately.
"We custom designed Kaiba's splint using high-resolution images from a CT scan of Kaiba's trachea and the bronchus that was collapsing," Green said. "Using computer-aided design and a special laser-based 3D printer, we produced the splint specifically to fit Kaiba's needs."
Months after these techniques were made public, Kaiba's dramatic progress continues to make headlines. His story even appeared on "Good Morning America." Sporting long wild locks and the same winning smile, he just keeps getting stronger. 3D printing and a team of brilliant doctors helped get him there and now the world is wide open for Kaiba and 3D printing technology.
- Matt Nixon, Writer
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