Surgeons at the University of Rochester have developed a program that employs 3D printing technology and allows them to build exact replicas of a patient’s anatomy in order to do full rehearsals of complex surgeries. University of Rochester Medical Center (URMC) urologist Ahmed Ghazi, M.D., used this method to build an exact replica of a patients kidney – complete with tumors.

A race against the clock

The patient Anthony Camneta’s suffers from von Hippel-Lindau syndrome – a rare genetic disorder. The gene responsible for suppressing tumors is flawed in von Hippel-Lindau syndrome, resulting in uncontrolled cell grow and division. This, in turn, can give rise to tumors in multiple organs which typically begin to appear in early adulthood. A few years ago, Anthony underwent surgery to remove a tumor from his brain. Physicians also spotted multiple tumors in both of his kidneys and his pancreas.

A few years ago, Camneta underwent surgery to remove a tumor from his brain. Physicians also spotted multiple tumors in both of his kidneys and his pancreas. Operating on Camneta’s right kidney posed a significant challenge. During the partial nephrectomy, the surgeons attempt to remove the tumors while preserving as much of the healthy kidney tissue as possible in order to avoid the need for dialysis or a kidney transplant.

While partial nephrectomies are typically performed using robot-assisted surgery. This technique is preferred because it is minimally invasive and results in a shorter recovery period, the surgeons decided to remove the tumors via open surgery. This approach allowed the surgeons to pack the kidney in ice; essentially putting the organ into hibernation and giving them more time perform the procedure once the blood supply was cut off.

However, this open surgical method has significant drawbacks. To get to Camneta’s kidney, the surgeons had to make a 10 centimeter incision in his side, cut through muscle, and remove one of his ribs. While the surgery successfully removed the tumors, it led to a long recovery period. “It was tough figuring out how to provide for my family because I wasn’t able to work and still I am only allowed to lift 25 pounds,” said Camneta.

Ahmed Ghazi, M.D., holds a lifelike model of Anthony Camnetar's kidney.

Ahmed Ghazi, M.D., holds a lifelike model of Anthony Camnetar’s kidney. (c) University of Rochester

When it came time perform surgery on his left kidney, which had five tumors, Camneta reached out to Ghazi, an assistant professor in URMC’s Department of Urology and the Wilmot Cancer Institute. Because of the complications from his first surgery, he wanted to explore the possibility of having the next procedure done robotically and had heard about Ghazi’s unique approach. “Robotic surgery is the preferred method for performing a partial nephrectomy,” said Ghazi. “It leads to less pain and faster post-operative recovery. Now that is the gold standard for one, maybe two tumors in the kidneys, but for five it is nearly impossible.”

Ghazi partnered with Jonathon Stone, M.D., then a resident in the URMC Department of Neurosurgery, to establish the Simulation Innovation Laboratory to develop a system of fabricating lifelike artificial organs, which would allow surgeons to practice complex cases in advance of the actual surgery.

Fake organs bleed when cut

The process begins by converting images obtained from MRI, CT, or ultrasound scans from the patient into computer-assisted designs (CAD). The CADs of organs are converted into molds, or negatives, which are built using a 3D printer. In a process akin to casting a bronze statue, the molds are then injected with a hydrogel which, after freezing, assumes a solid state.

By altering the concentration of the hydrogel, the team can add denser tumor mass and other components of the organ, such as blood vessels. The team also assembles entire segments of the body, complete with artificial muscle tissue, skin and fat, and, depending upon the area of interest, the liver, intestines, spleen, kidney, and other adjacent organs and structures. Artificial blood vessels are connected to bags of red dye that will “bleed” if cut. This process allows them to replicate the entire surgical process of guiding instruments to the right location, moving other organs out of the way, clamping blood vessels, and resecting and removing tumors.

“These rehearsals allow you to save operating time, decrease blood loss, potentially avoid complications, and prevent time you have to trouble shoot,” said Ghazi. “All of this directly impact patient outcomes.”

Intensive training

Months ahead of the planned surgery, Ghazi created five exact replica of Camneta’s kidney. He conducted full rehearsals in the operating room using the robots, including a final practice run the day before the actual surgery. “I started rehearsing using different game plans and deciding which tumors I was going to remove first,” said Ghazi. “And you can only figure that out by trying it a couple of times. It turns out that two of the five tumors could be removed before I cut off the blood supply and the rest needed to be done after the blood vessel was clamped.”

When the day came for Camneta’s surgery, Ghazi was confident he had developed the right approach. He successfully removed all five tumors, preserved 90 percent of the kidney’s function, and was able to restore blood flow in under 24 minutes. “Recovery was so easy,” said Anthony. “A week after surgery I was able to walk around. The last surgery I had it took about a month and a half for me to be able to walk around without pain. I was able to hold my son two and a half weeks this time as opposed to two and a half months.”

Source: University of Rochester Medical Center