When I walked into Dr. Sloane Guy's office Tuesday morning, he and a cardiac surgery nurse practitioner were surveying a detailed 3D image on his computer screen. It was a CT scan of a patient's heart. As Guy, an open heart surgeon, manipulated the image on the screen he and Amber Lennon, the nurse practitioner, discussed whether the patient would be a good candidate for robotic surgery, Guy's specialty. The other option would be the old-fashioned way, which would require a sternotomy, colloquially known as "cracking open the ribcage." They opted for the latter.
"We'll just have to let him know that this is the reason we do these studies, to look for things that may make him non ideal [for robotic surgery]," said Guy, who's also an associate professor at Weill Cornell Medicine in New York. "There's nothing wrong with a sternotomy. What's important is that we get him through surgery safely."
This is a standard scenario for cardiac surgeons like Guy. But he recently changed the way he approaches a surgery. Last month, for the first time ever, Guy used 3D printing to create a life-size model of a patient's heart and it completely changed the way he had planned to tackle a surgery.
It all started with a new patient who had an atrial septal defect: a birth defect that causes a small hole in between the heart's upper chambers. The patient had surgery on this defect before, but it wasn't completely closed. Looking at the CT scans, Guy could see the hole and figure out a game plan as usual. But he wasn't the only doctor on the case.
Dr. Geoffrey Bergman, a cardiologist at Cornell, was also looking at this patient's CT scans to determine if he could use a catheter to fix the hole, by using it to insert a small clamp-like device. But the position of this patient's defect was unusual, and it made it difficult to figure out from just the CT scan if this kind of procedure would work. So Bergman asked Cornell's medical 3D printing lab if they could make a physical, 3D-printed model of the heart out of the CT scans. They did, and Bergman was able to quickly determine that a catheter wouldn't work for this particular patient. So, he passed the model on to Guy.
The clear, plastic 3D model makes it very easy to see the defect. Guy held the model in his hands and poked a finger through the hole to show me.
"The traditional approach would be to go through here," Guy told me, running his finger along the model's right atrium. "You could do that, but it would require a sternotomy and the patient has had prior surgery, so it's a redo operation and there's scar tissue."
But looking at the 3D model, even I could see that coming at the defect from the other direction, through the left atrium, would allow Guy to get even closer to the hole. He told me it would also be less invasive and allow him to do the surgery robotically. This decision, to go in through the left atrium, was something Guy said he never would have realized if he didn't have a physical model to manipulate.
"That was the epiphany that I had," Guy said. "For the first time, for me, a 3D model was not just a gimmick. It was actually something that changed my game plan."
Guy is an early adopter of robotic surgery, in which the actual surgery is done via a robot that is controlled by the surgeon from a console. It allows for less invasive procedures and doesn't require a sternotomy. He's clearly not afraid of technological innovation. But he told me he was skeptical about using 3D printing for modeling.
"It seemed to have a lot of hype in the media, that's for sure," he said. "To me, it didn't seem like it would necessarily add a lot. I thought maybe it's a gimmick by the doctors to highlight their programs, but I think I was wrong."
Doctors use 3D printers to produce everything from emergency medical tools to prosthetic limbs. And other surgeons have even been able to use 3D printed models to practice surgery ahead of time. Though it's still a burgeoning field, more and more surgeons are coming to the same revelation Guy had, that there may be some merit to this technology after all.
Guy told me he's excited to start working with the 3D printing lab more often to see how it can contribute to his work. But Guy also thinks 3D printing will have even bigger impact on open heart surgery in the future: printing replacement parts out of your own tissue to fix any defects. While that kind of technology is still years away, Guy said it will significantly improve the way we treat cardiac defects.
"I'm certain that that's coming our way," Guy said. "It will eventually become a big deal."
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