These 3D printed human organ simulations were so realistic they fooled trained professionals

Researchers at the University of Rochester Medical Center (URMC) have developed a new way to fabricate human organ simulations that look and feel almost exactly like the real thing.
Picture a model “training” kidney that is almost indistinguishable from a real kidney, even to the point of bleeding when cut open. That is the objective of the Simulated Inanimate Model for a Physical Learning Experience, or SIMPLE, the groundbreaking program headed by urology professor Ahmed Ghazi and neurosurgeon Jonathan Stone.
Simulated kidney: a 3D printed mold injected with hydrogel
Where surgical training previously relied on rigid plastic replicas of human anatomy, SIMPLE fabricates lifelike organs that can be poked, prodded, and dissected. Through an intricate process of converting medical scans into computer generated designs, Ghazi and Stone make use of 3D printing to create organ molds which are then injected with an advanced hyrdogel that mimics human consistency.
“Very few surgical simulations are successful at recreating the live event from the beginning to the end,” Ghazi said. “What we have created is a model that looks, feels, and reacts like a live organ and allows trainees and surgeons to replicate the same experience they would face in the operating room with a real patient.”
Ghazi and Stone largely credit 3D printing advancements for their success. For the past two years, the pair have been refining their efforts: construction begins with the conversion of images obtained from MRI, CT, or ultrasound scans into computer-assisted designs (CADs); the CAD files are then used to 3D print molds, or negatives, of organs; finally, the molds are injected with a unique hydrogel and frozen solid.
The lifelike results are positively uncanny. More importantly, the SIMPLE program enables surgical residents and trained surgeons to update their skills and learn new surgical technologies in a far more accurate context than seen before. Medical students, who were previously limited to observing surgeries or practicing on cadavers, are also able to train on the 3D printed models.
Drs. Ahmed Ghazi and Jonathan Stone working on a 3D model
“Surgeons are just like pilots,” Ghazi explained. “There will always be the first time a pilot takes a 747 up into the air and there will always be a first time a surgeon does a procedure from beginning to end on their own. While pilots have simulators that allow them to spend hours of training in a realistic environment, there really is no lifelike equivalent for surgeons.”
For this reason, Ghazi and Stone weren’t satisfied with only creating models of anatomy. Rather, they wanted to be able to replicate the complete surgical experience. Guiding instruments to the correct location, shifting other organs out of the way, clamping blood vessels, and removing tumours are all crucial components in this process.
That means in addition to building the organs in question, Ghazi and Stone also needed to create the rest of the surrounding human anatomy so that every step of the surgical process could be replicated.
To accomplish this, Ghazi and Stone’s team assembles whole segments of the human body, complete with skin, fat, artificial muscle tissue, and even other adjacent organs. Even artificial blood vessels are hooked up to sacks of red dye that will “bleed” when cut.
In one case, Ghazi and Stone built a simulation of a cholecystectomy (laparoscopic removal of the gallbladder) that lets students perform the surgery in full. Everything from making the initial incision to final removal of the gallbladder can be done.
The extremely convincing nature of the simulation means that even trained professionals sometimes do a double take.
“We have had times when we are doing these simulations in the OR when nurses or other physicians have looked in the window and thought we were doing the real thing, and have even gone so far as to scrub and put their masks on before coming in thinking there was a patient on the table,” said Ghazi.