Multi-Material 3D Printing Meets Microscopic Surgery

Image showing a multi-material silicone liver model with tumors – 3D printed with ACEO®’s drop-on-demand technology

Multi-material silicone liver model with tumors – 3D printed with ACEO®’s drop-on-demand technology (Photo: ACEO®; Wacker Chemie AG)

Fredrick Johnson Joseph is a Ph.D. candidate at University Bern’s ARTORG Center for Biomedical Engineering. His research focuses on image-guided therapy for microsurgical applications, which is the basis of his recent project with ACEO®.

ACEO®: Mr. Joseph, thank you for sharing your story with us. You are a Ph.D. candidate at the ARTORG Center for Biomedical Engineering (ARTORG). What is ARTORG’s mission?

Fredrick Joseph: ARTORG connects the biomedical engineering and clinical departments of Inselspital, the University Hospital in Bern. More than 10 research groups or teams work directly with their corresponding clinical department at the Bern University Hospital. Their research topics vary from neuro rehabilitation to
organ on a chip.

You will find groups trained to build diagnosis systems, assistive technologies or medical instruments using methodologies such as ultrasound or CT. Other groups work on oncology and therapy, vascular disorders, or genetic engineering.

The goal of all our projects is to pave the way for biomedical engineering into pilot studies, clinical trials and eventually clinical adoption.

Can you tell us about your educational background?

I have a background in Medical Engineering. I studied at Anna University in India and researched at the Indian Institute of Technology, Madras. I graduated at the University Hospital in Magdeburg with working experiences also in addition with the University of Heidelberg in Germany, specializing in image-guided surgery and procedures.

What does your ARTORG research group focus on?

Our research topic is microscopic or minimally invasive surgery. We try to create better laparoscopic tools, navigation systems and presurgical planning software, using MRI or CT data. The goal is to identify the perfect access point for the surgery to remove only what is necessary using robotic assistance.

Take tumors for example. The space available for surgery is usually in a range of 10-20 millimeters average. Presurgical planning is essential, but one big challenge is that every patient body is unique, and so is every organ – no liver looks like another. When a tumor is removed, we need to ensure the healthy tissue is left unaffected by microsurgery. You don’t want to cut out too much of the organ itself and destroy vessels for instance.

The same goes for radiation: It is essential that only the diseased tissue is treated. Some vessels and channels carry important hormones so you cannot destroy them because otherwise, you will lose essential functions of the organ. In a nutshell: You must be very precise and accurate in what you do.

Another challenge is time: tumors sometimes grow very fast. One to two weeks in between an examination with MRI or CT and the operation might make a big difference how the tumor really looks at the time of surgery. So, unfortunately, there are some things we cannot research without a patient-specific model because of the course of diseased anatomy with respect to presurgical planning, training surgeons, and building new robotic medical systems.

What technologies do you use in your research?

Demonstrating the benefits of our research and validating it needs proof. When you develop a technology in the medical field, you need to authorize it carefully before you take it to the patient. There are several steps of consents required, and the regulations are obviously very strict.

For our field, animal validation – which is also strictly regulated – is not applicable. You will rarely see striking similarities between the organs of humans and animals. The different geometries cannot be used for image-guided surgeries especially when the robotic system is trained for similarities under machine learning and artificial intelligence.

Coming back to our challenge: Creating an artificial organ is the only way to go, but it can be very patient specific as I mentioned earlier. You need some system equivalent to a human organ. It must somehow look and feel the same as the individual organ and must mimic its functionality and physiology to some extent. The surgeons we support in their surgeries and for presurgical planning need to have haptics and tactility of the target organ before they go into the operating room. As the visual dimensions are very limited in radiological imaging, we wanted to create a 3D printed model of a liver with tumors for our case.

To answer your question: If you only want to replicate the geometry of an organ, you can use a variety of methods such as casting, additive manufacturing and rapid prototyping methods such as 3D printing. But if you want to replicate the anatomy of the organ, you will need to consider that a tumor is rather hard, while a vessel and the liver tissue is rather soft.

Therefore, you have to go with 3D printing because we can replicate accurate anatomical positions similar to the patient body with very few differences. Currently there are some limitations with respect to resolution and printability of certain materials, but we believe this is only a matter of time.

How did you come across ACEO® for your research projects?

I was not happy with the other forms of additive manufacturing and rapid prototyping methods we previously followed. Conventional manufacturing methods were good for larger objects but microscopic structures could not be produced in the desired quality.

So I started looking for 3D printing solutions with the motivation to recreate an artificial organ with different synthetic materials. We developed our ideas and reached out to Wacker’s ACEO® team on their expertise. We were the very first test users for multi-material 3D printing at ACEO®.

I realized their solution was superior to other methods available in the market. ACEO® had the capability to show me the difference by using different materials and hardness of a 3D printed liver. The result of multi-material 3D printing with silicone: it looked very much like the real organ model. And it was more precise and accurate than other methods.

Do you see this technology as part of your industry for the future?

Ultimately, it will be a question of capability: Can I print 100 organs rapidly in few hours before the surgery? Can I print different materials and micro details with complex geometry? Medical technology is very advanced, and if ACEO® can meet the requirements of production time and dimensions, I expect there is a huge demand on an industry level in the next 2-3 years.

I already see great potential for ACEO®’s electrically conductive silicones. They cover not only physiology but also functionality – a perfect match for researchers in the areas of neurological research who need to evaluate electrical impulses. I look forward to following what ACEO® comes up with next.