First came X-rays, and then CT scans, and then MRIs. Now, technology is not only giving surgeons the best view yet of organs as complex as the heart and liver; it's also letting them hold exact replicas of the organs in the palms of their hands.
Cleveland Clinic is among a handful of institutions in the nation using three-dimensional printing technology to create exact models of human organs. Surgeons at the medical center take an exact replica of a patient's liver into the operating room with them.
The idea is to better understand the anatomy of the diseased organ during surgery. A surgeon cannot always tell using traditional imaging techniques exactly where blood vessels in the liver are. They may be so close to the surface that they're at risk of being nicked with a scalpel.
The model liver shows the exact location of the vessels, allowing the surgeon to operate with precision.
Dr. Nizar Zein of Cleveland Clinic told Healthline he is already using the liver models during surgery. It allows doctors to take time out during surgery and refamiliarize themselves with where they are in the procedure.
He said patients have been coming to Cleveland Clinic after being turned down by other institutions. Liver surgery is extremely risky and can be further complicated by other factors—the location of tumors, for example. The models have allowed Cleveland Clinic to take on even the toughest cases, Zein said.
How Long Until We Can 'Print and Transplant'?
But what needs to happen before doctors can print real livers, hearts, and other organs for transplant into humans?
Several hurdles are standing in the way. One is finding widely available materials suitable for use inside the body, said Jordan Miller, an assistant professor of bioengineering at Rice University. “So far, manufacturing has been on hard, dry, rigid materials. But the body is soft and wet. It doesn't translate.”
The safety of the materials would also need to be evaluated by a regulatory agency, such as the U.S. Food and Drug Administration, Miller said.
He told Healthline that an even bigger challenge he's working to solve is how to re-create a human's vast network of blood vessels in printed organs. “The blood-vessel network in the liver or a kidney is quite beautiful, but from an engineering perspective, it's quite terrifying,” he said.
Functional printed organs need to be made from human tissue and cells. Scientists still need to figure out how to keep human cells from dying during the printing process.
Through modern science, skin or fat cells can be converted into stem cells that can then be grown into cells of any type. But it takes a tremendous number of cells to make a functional human organ, Miller said. He is trying to figure out a way to get proper blood flow, or vascularization, to cells in 3D printed organs. Otherwise, they cannot get oxygen and nutrients in such a dense environment and will die.
But scientists are working toward the goal of printing live livers, hearts, and other organs for transplantation. Because of the scarcity of donated organs, which can be used only for a short period of time, this advancement could save countless lives.
“When a transplant surgeon gets a liver, it's only going to stay alive for a few hours, and you need to find a recipient very quickly,” Miller said. “What if we can print something that would have vasculature that you could connect directly? That's the key challenge in our field.”
Printing Hearts for Kids
David Frakes, an assistant professor of bioengineering at Arizona State University in Tempe, is working in a program similar to Cleveland Clinic's. He has teamed up with the Children's Hospital of Philadelphia, which is printing exact heart replicas for its surgeries.
He told Healthline he is gratified to see his work make a difference in medicine so quickly. “As bioengineers, we work for five years if we're lucky—[it's usually] more like 10 or 20—before we come up with something that can be infused into medicine and affect people's lives. Surgeons work with their hands, in real space. They are not in a 3D virtual environment.”
Researchers at the Children's Hospital of Philadelphia plan to begin tracking outcome data of patients whose doctors used a printed replica during surgery. “This is an exciting thing that will offer quantifiable data," Frakes said. "Printed organs are super cool, and everybody loves talking about it anecdotally, but so far trials have not been done.”
Zein said it likely will be 10 to 15 years before doctors are able to print out an organ and put it inside someone. “It is not in the very, very far distance," he said. "Conceptually it has been proven. Whether or not we can accomplish a fully functional organ with specific purposes, I am not certain, but it certainly is an achievable goal at this point.”