If the term “3-D” makes you think of action movies and goofy plastic glasses, you might be surprised to know that today’s 3-D technology can do much more than entertain us. It can save lives. Modern 3-D printing can be used to help surgeons prepare for heart procedures, to facilitate communication between medical professionals and families and to create realistic three-dimensional models of objects — including the tiniest of human hearts. Five-year-old Riley Drummond of Olney, Illinois, was born with several congenital heart defects. Her heart lay on the wrong side of her body, a condition called dextrocardia. She had two holes in her heart: an atrial septal defect and a ventricular septal defect. Riley also had a tunnel subaortic stenosis — an obstruction under her aortic valve.
After two open heart surgeries, Riley’s primary cardiologist, Jamie Sutherell, M.D., a SLUCare cardiologist at SSM Health Cardinal Glennon Children’s Hospital, discovered an aneurysm during a routine echocardiogram. He needed to better visualize what was going on, so he ordered a magnetic resonance angiography — an MRI exam of the blood vessels.
Using the images from this scan, fellow cardiologist Wilson King, M.D., a SLUCare cardiologist at Cardinal Glennon, created a 3-D printed replica of Riley’s heart, which the doctors could actually hold in their hands while evaluating treatment options.
Next, Riley’s cardiothoracic surgeon, Andrew Fiore, M.D., SLUCare cardiothoracic surgeon at Cardinal Glennon, used the 3-D model to plan out virtually every step of Riley’s surgery. The goals of surgery were ambitious: to repair the aneurysm within her heart, and to widen the subaortic tunnel.
“It really required us to put our heads together, using different tests and modalities to provide critical information to give to Dr. Fiore,” Dr. Sutherell says. “You want everything in place first and to know what you’re dealing with. You never want to do an ‘exploratory’ heart surgery.”
At Boston Children’s Hospital, Sitaram Emani, M.D., says that 3-D printing has forever changed the landscape of pediatric cardiovascular surgery. He explains that analyzing a patient’s heart prior to an operation reduces the amount of time surgeons spend figuring out the cardiac anatomy during the surgery — and it’s also safer for the patient. “We’ve already learned so much before we open the chest,” says Dr. Emani, who was not involved in Riley’s case but is well versed in using 3-D printed heart models for his own patients.
“In the past, we would attempt these complex surgeries using only two-dimensional imaging. Then we’d mentally reconstruct and anticipate what we might do during the actual procedure,” he says.
3-D printing in the medical field has wide applicability, he says, and bodes well for future advancements. “We can use the technology for an entire patient simulation and even replicate blood flow with a heart-lung machine,” Dr. Emani says.
3-D printing has enabled SLUCare physicians Wilson King and Nadeem Parkar, with support from Parks College of Engineering at Saint Louis University, to understand a patient’s heart condition with tremendous detail and clarity. In conjunction with Saint Louis University School of Medicine, Drs. King and Parkar have printed dozens of heart models to assist with complex surgeries, interventional cardiology procedures and electrophysiology procedures.
Physicians at Cincinnati Children’s Hospital Medical Center are also using 3-D modeling to help congenital heart patients. Ryan A. Moore, M,D., a pediatric cardiologist with specialized training in CT/MRI imaging and 3-D modeling at the hospital says, “A lot of attention to detail is required when we make a model so that everything ‘fits’ just as the imaging looks to us.”
Like Riley’s care team, Dr. Moore uses images from CT or MRI angiograms, and even occasionally echocardiograms, to make his models, loading them into computer software. Then he saves a stereolithography file, which is required for 3-D printing. The 3-D printer builds up a model layer by layer with liquid polymer that hardens when the UV or laser light contacts it.
“Instead of the printer laying down ink on paper, it lays down liquid polymer using similar technology,” Dr. Moore says. “It allows us to better describe and illustrate defects in a way that’s far superior to drawing on a piece of paper.” Dr. Moore prefers to use the technology for very complex cardiac cases — about 10 to 20% of the total cases he encounters.
Having a 3-D printed model of a patient’s complex heart allows not only for better surgical preparation, but also better communication among cardiologists and family members.
“I may not be able to adequately describe in words to a patient, family or another doctor the type of surgery I need to do, but this allows for the ultimate method of transferring information instead of just using diagrams and ‘beating around the bush,’” says Dr. Emani of Boston Children’s.
“We can transmit important information between caregivers, such as cardiologists or imaging specialists, who don’t normally see the heart the up-close way we surgeons do,” he says. “The fact that this is so visual helps everyone on the team do a better job for our patients.”
As surgeons and patients benefit from 3-D printed replicas of organs, researchers in the U.S. are developing 3-D printers that can lay down layers of cells to create actual working organs for implanting in the human body. For instance, at Wake Forest Institute for Regenerative Medicine in North Carolina, scientists have made a 3-D printer with a nozzle that lays down a water-based solution containing human cells. A different nozzle exudes biodegradable materials to support those cells. As the materials biodegrade, what’s left is human tissue that can accommodate blood vessels. So far, the researchers have successfully implanted 3-D printed pieces of jawbone, muscle and cartilage in mice.
Meanwhile, Riley’s mother, Micah, is so grateful for what 3-D has done for her daughter. “The 3-D model allowed Riley’s doctors to practice, study and collaborate,” Micah says. “In essence, this technology saved Riley’s life.”