From Sci-Fi to Fact
Emerging medical applications of intricate 3-D printing techniques are changing — and saving — lives
Less Guesswork: Doctors like Kongkrit Chaiyasate can use custom models made with 3-D printers to help plan actual surgeries as well as explain surgical procedures to patients.
Photograph by Martin Vecchio
When the doctor pulled the plastic skull out of the box, Southfield mother Shaura Pearsall instantly recognized it as the head of her infant son, Jonah.
“It looked exactly the same except for the smile on his face,” says Pearsall. Jonah’s Crouzon syndrome prematurely fused his skull and facial bones, inhibiting their growth, distorting his head’s shape, and threatening his brain development.
As Beaumont Hospital’s Dr. Kongkrit Chaiyasate showed Pearsall the custom model, made with a 3-D printer, special software, and Jonah’s CT scan to explain in detail the surgery he proposed, she could see how thin her child’s skull was, and therefore easy to cut and reshape. It also helped Pearsall ask questions and better fight the battle of being a parent to a special needs child.
“Something like this helps to put some of the power back in your hands,” she says.
The medical community’s adoption of 3-D printing is triggering big changes. Also called additive manufacturing, 3-D printers make items by layering metal, plastics, wood, and other materials.
While 3-D printing has been used in the auto industry for rapid prototyping since the 1980s, and more recently for controversial DIY handguns, its medical uses are exploding in a way reminiscent of the glory days of American manufacturing.
It’s helped bring medical devices to market faster by fashioning prototypes quickly, make life-changing and life-saving implants tailored to an individual’s own anatomy, plan and perform surgery like knee replacements and Jonah’s procedure using patient-specific models, and teach doctors in training.
In short, 3-D printing is unique: It can be used to manufacture intricate items that would be impossible to make any other way.
Mike Moceri, CEO of Manulith, a 3-D printing product development company at TechTown in Midtown, taught himself the process and built his own 3-D printer after his freshman year at DePaul University. He dropped out during his junior year and started a 3-D printing store in Chicago before moving back to his hometown to establish Manulith.
“There’s really no university that teaches 3-D printing,” he says. While that may be a slight overstatement, it’s definitely still an emerging technology.
As far as the medical community goes, 3-D printing of replacement organs and human tissue to test new drugs remain just barely science fiction. But custom-made patches to fill gaps in skulls and DIY hand prostheses are science fact.
So, too, are dissolvable splints made at the University of Michigan for babies whose airways collapse. U-M’s Dr. Glenn Green, a complex airway reconstruction specialist, has implanted several of these splints, designed to help until the cartilage in a baby’s trachea can develop and stay open on its own.
Green’s colleague Dr. Scott Hollister, who 3-D prints the babies’ splints, also made a dissolvable prosthetic jawbone for a man in Milan that was seeded with “growth factor” — a substance to stimulate cellular growth. The idea is that, as the man’s own replacement bone grows, the prosthesis will dissolve, just like the babies’ splints.
Green and Hollister have also collaborated on a permanent trachea splint for adults with a life-threatening autoimmune disorder that weakens their airway cartilage.
“If somebody’s going to die immediately we can put it in,” Green says.
Hollister, who’s been 3-D printing since 1996, also has ongoing pre-clinical studies for replacement ears and noses; arm, leg, and facial bones; and devices for spinal fusion. “In the future, we would print a scaffold and seed it with cells,” he explains, referring to a person’s own stem and growth factor cells.
Meanwhile, Henry Ford Hospital is taking some of the guesswork out of catheter-based aortic valve replacements by printing 3-D models of patients’ hearts that doctors use to determine a more exact valve size.
“We simply don’t have adequate sizing tools,” says Dr. William O’Neill, medical director of Henry Ford’s Center for Structural Heart Disease.
That’s important because an undersized replacement valve can leak and lead to heart failure, O’Neill explains. Even a correctly sized implant could interfere with other structures inside the vital organ and block blood flow if not placed correctly, he explains. In addition, knowing in advance what to expect can speed the procedure and reduce a patient’s time under anesthesia.
O’Neill says Ford plans to formally study using old measuring techniques vs. using 3-D models.
“If it works for us we want to demonstrate it so other people could use it,” he says.
At Beaumont, Chaiyasate has another use for 3-D printed models, in addition to enlightening patients and parents: He uses them to plan his surgeries. Lines he’s made with permanent marker on his “library” of models show where he cut the skull during complex microsurgeries on children and adults. In surgeries more intricate than Jonah’s, whose skull was cut in two, some sections are also marked with letters, like misshapen Scrabble tiles, to help him reassemble the skull.
“Could we do it without 3-D?” Chaiyasate asks. “I think we could, but it would be less precise. In the past, we just eyeballed it and did a lot of guessing.”