Surgeons can utilize the 3D model developed by Fitski in various ways: on a screen or as a hologram. For children where kidney-sparing surgery was previously too risky, the risks are now lower. The 3D model enables the surgeon to locate and remove the tumor more accurately. Fitski will defend his thesis on Wednesday, 3 July, at Utrecht University. We asked him a few questions about his research.
What is the most important result of your PhD research?
‘The most important result is that surgeons can now more often remove all cancer cells during a kidney-sparing operation for a tumor. This is because the surgeon uses a 3D model, which I developed and researched. The results will soon be published in a scientific journal. The 3D model helps the surgeon to better and more accurately remove the tumor. As a result, children with kidney cancer need fewer additional treatments such as chemotherapy or radiotherapy. The children recover better and faster from the disease, with fewer side effects.’
Why doesn’t the surgeon remove the entire kidney if there is a tumor? We have two kidneys, after all.
‘Kidney-sparing surgery, as we call it, has many advantages for children. Preserving as much healthy kidney tissue as possible is important for children with tumors in both kidneys and for children with a genetic syndrome that increases their risk of kidney problems later in life. By saving part of the kidney, more kidney function is retained. Even in children with small tumors in an easily removable location, we can sometimes save part of the kidney. This helps prevent problems such as high blood pressure and kidney failure later in life’
How does the 3D model work that you developed?
‘It is often difficult for the surgeon to determine exactly where the tumor is in the kidney. It is also challenging to see how much space there is around the tumor and where exactly the surgeon should cut. To perform kidney-sparing surgery well, I devised a technique that creates a 3D model of the kidney tumor.
This consists of two steps. The first step is a new type of MRI scan that clearly shows the blood vessels of the kidney. The second step is a fast-working computer program that makes a 3D model from these MRI images. We make a unique 3D model for each child. The surgeon looks at the model before and during the operation.’
How does the 3D model help the surgeon to have a better view on the tumor?
‘The 3D model can be displayed in different ways. You can print it or view it on a screen. You can also make a hologram of it. A hologram is a 3D image that seems to float in the air. You can view a hologram from different angles, just like with a real object. The surgeon then wears a HoloLens. This is a pair of glasses with a transparent screen that can project a hologram into the real world. Initially, we used holograms only before surgery to make a good plan. The surgeon can look into the kidney and see all the structures well. But you can do more with a hologram. You can also use it during the surgery. The hologram can even move to the right position with the help of special computer programs. This allows surgeons to see even better where they need to operate.’
Video: Matthijs explains how the HoloLens works
Have you also received feedback from other surgeons on the 3D model and your HoloLens?
‘Yes. We collaborate with surgeons from other pediatric cancer centers. We are also starting new research in this area, for example with St. Jude Children’s Research Hospital in the United States. We are at the forefront of developing these techniques and want to further develop this together with them. We also work with the Sant Joan de Déu hospital in Barcelona. They have a lot of knowledge about 3D printing models to use during surgery. That is something we can learn a lot from.’
What are the next steps in your research?
‘We want to use the 3D model for other types of childhood cancer. For example, for neuroblastoma. This tumor is in the abdomen, often near important blood vessels. During surgery, the surgeon has to navigate through these. With the 3D model, we try to make this clearer. This way, the surgeon can better see where the risky spots are. Another idea is to use the 3D model to explain the surgery to children and their parents. Surgery is often scary for a child. We want to make 3D prints in multiple colors. This makes it easier for children to understand what will happen. They can hold and view the model.
Another next step our team is working on is combining ultrasound with 3D models during surgery. This helps the surgeon to determine the exact boundary between healthy kidney tissue and tumor tissue. Ultrasound is currently still in 2D. By combining this technique with our 3D models, we can generate an even more complete picture. This allows the surgeon to remove the kidney tumor even more accurately. This fits within our mission to cure every form of childhood cancer with the best possible quality of life.’
About this PhD defense
Matthijs Fitski is a technical physician and PhD candidate in the research groups of prof. dr. Marc Wijnen and prof. dr. Marry van den Heuvel-Eibrink. A technical physician integrates medical and technical knowledge to optimise diagnosis and treatment. Fitski will defend his thesis on Wednesday, 3 July, at Utrecht University with the dissertation 'Introducing new dimensions in paediatric oncologic surgery.’