3D Livers: a Medical First!

On average, there are 16,000 people on the waiting list for a liver transplant. Finding a live donor is becoming a feasible option for many patients. But the surgery can be risky for recipients and donors. Now, doctors have a new way to make transplants safer and it's a medical first

When Mollie Moreland found out her brother-in-law, Chris, needed a liver transplant — she offered to be the donor.

"I was so touched by just her generosity and her courage," Chris Wagner told Ivanhoe.

The 24-year-old didn't think twice when doctors told her she would have to give two-thirds of her liver to Chris, and had up to a one in 200 chance of dying.

"There's no turning back. He needed it," Mollie Moreland told Ivanhoe.

Before the transplant— surgeons at the Cleveland Clinic took images of Mollie's liver and printed a 3D replica that was an exact copy of the organ. They are the only doctors in the world doing this!

"We may be able to improve on the outcome and decrease complications," Nizar Zein, MD, Chief of Hepatology and Medical Director of Liver Transplantation, Cleveland Clinic, told Ivanhoe.

The 3D organ is transparent, so surgeons can see all the major veins, arteries, and structures. They use it to plan surgery and even make decisions in the operating room.

"This physical model, you have it in surgery. You are able to manipulate it the same way you do for a person's liver," Dr. Zein said.

Chris recovered– and Mollie's liver regenerated two weeks after surgery.

"She's just been just amazing about the whole thing," Chris said.

So far — Cleveland Clinic surgeons have used the 3D livers in about 25 surgeries. They hope to also use the models for tumor removal surgery and to one day create real organs in a lab to use in transplantation. Mollie and Chris started a charity to raise awareness and money for live donors.

ORGAN DONATIONS: Experts say that the organs from one donor can save or help as many as 50 people.  Skin, cornea, internal organs, bone, and bone marrow are all organs that can be donated to another human. When people decide to donate their organs, they typically donate internal organs to family or friends. Most organ and tissue donations occur after the donor has died.  However, some organs and tissues can be donated while the donor is still alive.  There are no limitations on who can donate.  Whether you can donate depends on your physical condition, not age.  Newborns as well as senior citizens have been organ donors.  Non-resident aliens can both donate and receive organs in the U.S.  Organs are given to patients according to medical need, not citizenship.  In 2001, 334 (2.7 percent) of the 12,475 organ donors were non-resident aliens.  In this same year, 259 (one percent) of the 23,998 transplants performed were on non-resident aliens. (Source: http://www.organdonor.gov/faqs.html, http://www.nlm.nih.gov/medlineplus/organdonation.html)

NEW TECHNOLOGY: During an organ transplant procedure, doctor and surgeons usually have to rely on MRIs and CT scans to remain oriented. But doctors at the Cleveland Clinic now have a new tool to help them during organ transplant procedures. Using a 3D printer, they can print color models of a patient's organs. The 3D model provides numerous advantages to a 2D scan of an organ: "Holding the model and being able to look at it from all directions will give you that extra sense of confidence as far as understanding the spatial relationship of different structures during the operation. The second big advantage is that we use a transparent material to print the liver," Cleveland Clinic Dr. Nizar Zein was quoted as saying. The model allows doctors to have it in surgery with them in case they experience "surgical disorientations," where they essentially get lost. The overall goal of a 3D printed organ is to decrease complications during surgery, which in turn can help decrease them after surgery. (Dr. Nizar Zein)

Nizar Zein, M.DNizar Zein, M.D., Chief of Hepatology and Medical Director of Liver Transplantation at the Cleveland Clinic, talks about using 3D printing for liver transplants.

The liver transplant procedure is pretty dangerous, right? Even in healthy people?

Dr. Zein: It is a complex and major surgery by all accounts. While complications may occur, liver transplantation is a life-saving surgery to many. A particularly more complex surgery is live donor liver transplantation where a healthy person donates a piece of their healthy liver to another sick individual. In this case, when a complication happens in somebody who is otherwise healthy – who is just being a good human being – it then becomes a really big deal. Although fatality during this type of operation is extremely uncommon; one fatality is one too many. Our ongoing interest in minimizing the risks of liver transplantation has been the real driver behind the development of 3D printing of human livers; we endeavor to find ways to decrease complications and the potential mortality of the operation.

Most people think to be a match you just have to be a blood match, but it also has to do with height and body type; can you explain that?

Dr. Zein: In addition to blood type matching, the donor has to be, in terms of weight and size, somewhat close to the recipient.  Also, the portion of liver that is to be removed from the donor and given to the recipient patient should be of a certain size; the donated portion needs to support the recipient and have the ability to grow into a full functioning liver. An accurate measurement of liver volume prior to the operation is critical. Furthermore, precise knowledge of the anatomy of each individual liver is a key to success and the avoidance of complications. This has historically been done through imaging (x-ray) but has its own limitations. These limitations are anticipated to be overcome by the 3D printing.

So before you had the 3D liver you were completely reliant on scans to see if everything would match up?

Dr. Zein: This whole idea of a three dimensional physical model of the liver was born out of our continuous careful watch over complications and the desire to decrease them. So, there's always a desire and a need to know the exact anatomical structures of the liver (knowing that there are individual variations from one person to another) before going to the operating room. We had CT scans, we had MRIs, but they fell short of giving the entire picture.  This is, in part, because these images are examined through a two dimensional (2D) view on the computer screen. Looking at these structures in 2D is not really optimal as one may lose the ability to get a sense of the depth and spatial relationship of different structures (blood vessels, bile ducts, etc.). The recent development of three dimensional (3D) images is intended to overcome some of the limitations listed previously; however, the images still have to be examined through a 2D computer screen. So, this whole idea was really conceived in my office one day. We were talking about what can be done and how could we overcome some of these limitations. I was aware of 3D printing as used in engineering and the fashion industry but had noticed that 3D printing was making a very slow entry into medicine. Having a physical model, a replica of the patient's liver, available for the surgeon prior to the operation would be a great improvement.  The entire operation could then be envisioned on the physical model for optimal planning in advance of surgery.  Our group is currently working toward this end in order to improve outcomes and decrease complications. That is how we embarked on this whole project.

What can you see on the 3D model that you wouldn't be able to see on a scan?

Dr. Zein: There are several potential advantages that we are in the process of validating. The physical model allows you to utilize the tactile sense of the liver; you cannot touch the liver on the computer screen but here you can actually touch its replica, move it around and look at the 3D relationship of different structures. Holding the model and being able to look at it from all directions will give you that extra sense of confidence as far as understanding the spatial relationship of different structures during the operation.The second big advantage is that we use a transparent material to print the liver. The human liver is not transparent, so at times during the operation, an unintended deviation from the planned cutting plane happens (sometimes referred to as "surgical disorientations") and can be a cause of complications. The 3D liver is an identical copy of the patient's liver yet it's transparent; the model can help in re-orienting the surgical team to the safest cutting line to follow. This transparency also provides the ability to see through all major blood vessels ( the three major hepatic veins, the hepatic artery branches, and the branches of the portal vein) in order to avoid those structures surgically when needed.

You have this with you in the surgery then?

Dr. Zein: Yes. In addition to being transparent, this physical model is light-weight and transportable to the operating room. During surgery, it allows the surgeons to manipulate the 3D model into the same orientation as the patient's liver may be situated on the operating table.  As surgery progresses, the patient's liver doesn't stay in one position; rather, surgeons may have to push it around, move it up, or move it down into positions which are unable to be matched to the stationary view of a CT scan or MRI. A physical model allows the surgeons to move the model to the correct view. So, once again it helps surgeons maintain the proper orientation of an important structure during the operation.

How long does it take to create one?

Dr. Zein: I don't know; and the reason I say that is because it's evolving. In fact, with the earlier models it took us a few months because we were still learning. Various materials were tested for use in printing; different colors were tested, etc. It was important to identify material in which the consistency and color will remain stable over a long period of time. So the process has gone through an evolution.

At the present time, we are able to produce a model in 1-2 weeks but the turnaround time will likely come down substantially very soon.

What is that made out of?

Dr. Zein: It's a polymer. We tested different polymers and materials. More recently we used plastic.

Could you use this for all types of surgery, all types of transplants?

Dr. Zein: In medicine, as you are aware, we can't just say "yes we can" without providing evidence of the usefulness of the concept. So, as I said, we have a complete program at this point to develop these models; starting with liver transplant surgery, we identified a potential use and benefit. Moving forward, we have models for resection of complex liver tumors and expanded into other organs - pancreas, complex facial plastic surgery, etc. Most recently, we have been focusing on the use of these realistic 3D printed models as a novel tool in medical education. We are experiencing success in this area. Physical models matched with specific CT scan images are now in use.  They are valuable in the training of young physicians and are aiding them in learning the accurate interpretation of these images by transforming the images into a 3D structure.



Andrea Pacetti

Cleveland Clinic