Pediatric Surgeons Use 3D Printing To Help With Complex Operations
Before Lincoln Matthews underwent his most recent complicated heart surgery at Rady Children's Hospital, his doctor held a 3D-printed replica of the small boy’s heart in his hands to practice the procedure.
“This is like the size of it and the color of it and what it looks like,” Matthews explained, as he proudly showed off his model heart encased in glass at his North County home.
After three open heart surgeries, the 7-year-old knows a lot about his most precious organ.
“It pumps normally, but sometimes when I’m beating my heart it stops, but then it keeps going,” Matthews said, with big bright eyes, as he described the pacemaker inside of his chest.
Matthews was born with just one working ventricle and a hole in the place of the other. His heart was also tilted to the opposite side of his chest.
His three-dimensional, life-size model, detailing every valve, vein and artery clearly showed the complication, and where doctors would have to reroute the blood flow.
Matthews' 3D model was created by Justin Ryan, director of Rady Children’s Hospital’s new 3D Innovations Lab, which opened in October. It’s one of the first 3D hospital labs in Southern California.
Ryan said the 3D models help doctors plan for complicated surgeries and improve outcomes of the region’s youngest patients.
“So in this patient, there’s a hole, which is kind of deep inside the model,” Ryan explained, holding up a cardio model inside the new lab. “And exactly how big that hole is can change the course of surgical correction. You need to know how big the patch needs to be, and where that patch might need to be in order to fix that hole.”
“We can also identify, when there’s a lot of tiny little blood vessels, which ones might be more critical to save or which ones can be sacrificed in order to help flow to other regions,” Ryan said.
Ryan, who holds a Ph.D. in biomedical engineering, churns out about a dozen 3D models every week, from hearts to spines, to skulls.
To create the models, he uploads a patient’s medical images into a special computer program.
“And they need to be three dimensional in nature, so that’s going to be a CT scan or MRI or 3D ultrasound,” Ryan said. “And that will allow us to create a 3D computer model which then gets sent to a 3D printer.”
The models are printed one thin layer at a time using resin or nylon powder, or liquid plastic. After printing, the models are put into an air blasting machine to blow off the excess.
Ryan said creating a spine with airways takes nearly 20 hours.
“A heart the size of my hand might be finished in four hours,” Ryan said.
Some models are printed in color to make it easy for patients and their families to better understand the diagnosis and surgery plan, he explained.
“So if you’re able to say, 'That purple chamber is connected to the red and blue vessel and it shouldn’t be that way,' you create a new way to communicate with families,” he said.
The colors also help surgeons differentiate who is going to work on which part.
“And we actually sit and analyze the models and that helps us understand what is the optimal approach to repairing the defect,” said John Nigro, M.D., chief of Rady Children’s cardiac surgery and director of the Heart Institute. His team performs nearly 400 open heart surgeries every year and nearly a dozen heart transplants.
Dr. Nigro encouraged the opening of the lab and recruited Justin Ryan after working with him in Arizona. The 3D models are crucial, he said.
“They really do help our children who have the most complex disease and are the sickest,” Nigro said. “And it really makes a huge difference.”
Nigro said holding a replica life-size anatomy in his hands to study difficult anomalies is empowering. He compared working without a model to driving without GPS.
"Before, I think we kind of had an idea in our mind, but you know, sometimes we would be fooled,” Nigro said. “We would get in and it was a little different than we had anticipated or that how our mind had anticipated.”
Most importantly, the models help reduce the risk of surgery to the child, Nigro said.
“We decrease the time that the child is actually on the bypass machine and in the operating room,” he said. “And that definitely translates to less complications, and better long term outcome.”
Lincoln Matthews, who loves to play soccer and golf, said he’s feeling much stronger these days.
“Like, I couldn’t run that fast, but since a month ago I can run super fast," he said.
But the first-grader faces another surgery down the road.
“When I’m 21, my mom says I have to have a heart transplant," he said. "So my mom hopes they have something to put inside my body to help it."
He said he hopes his experience will help other children facing difficult surgeries, and shared some advice:
“Be brave and know that you’re very special,” he said.