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Article by Rayana Nafisa & Margaretha Morsink
3D-printed Personalized Liver Models for Surgical Practice
Source Publication:
3D Printing of self-healing personalized liver models for surgical training and pre-operative planning, Nature Communications, 2023
Lu et al., Yuhua Zhang Lab.
For complex liver cancers which require surgical removal, surgeons rely on extensive pre-operative planning and visualization of the liver and the cancer within. Surgeons use images from computed tomography (CT) or magnetic resonance imaging (MRI) to create a 3D rendering of the liver, however, this is only displayed on a 2D screen, thereby limiting the usability. Thus, 3D printing of the liver offers an alternative to provide a detailed understanding of the spatial depth of the liver cancer and the relationships with the blood vessels. These researchers take 3D printing of personalized liver models to the next level. They use a special bioink to bioprint a liver with liver-like softness and self-healing capacity, so that surgeons are able to practice the tumor removal multiple times before the actual surgery. Overall, this innovative technique can be utilized as a novel preoperative planning tool as well as an educational tool for surgical trainees.
What did these researchers do?
The researchers aimed to develop a 3D-printed personalized liver model with liver-like stiffness. To achieve this, they first developed a novel 3D printing resin, which is the material used for printing. This material is required to have the stiffness of the liver, to accurately mimic a liver surgery. Moverover, self-healing abilities of the bioink allow for the reusability of the bioprinted liver, so that the surgery can be practiced multiple times. To produce this soft material to replicate a liver organ and create its self-repairing ability, they used a combination of biomaterials and tested multiple compositions. They were able to generate the ultimate bioink that not only mimics the liver-like softness, the liver is also able to replicate similar deformations to a real liver when under external forces, such as the movements of breathing. After confirming the self-healing capabilities at room temperature, the researchers used real clinical data to bioprint personalized livers with tumors of actual patients. The surgeons and surgical trainees were able to practice the surgery on these models by experimenting with different cuts to determine the most suitable approach for resection of a tumor.
Why is this important?
The creation of 3D liver models is a breakthrough for surgeons and surgical trainees, as it enables realistic practice of the surgery before the actual surgery. Having similar properties between the model and the actual organ provides surgeons with an almost real-life application to precisely cut in areas of the liver with a complex structure surrounded by vital blood vessels. Thanks to the model’s self-healing capacity at room temperature, surgeons can plan out the tumor resection at multiple angles to find the most optimal way of removing the tumor without damaging these vessels. It is especially important to obtain a negative margin, which means the entire tumor is removed. This model enables surgeons to find the optimal cuts to obtain a negative margin. When a positive margin is obtained during the practice, the liver model heals entirely, and the surgeon is able to try again. This will have a tremendous impact on the recovery of the patient and their ability to heal from cancer. Moreover, surgical trainees are able to practice their surgical skills on a relevant model without the use of human cadavers - a limited resource with ethical constraints. They are able to make multiple cuts without facing the consequences of making a mistake during surgery, while sharpening their surgical skills.
How did the researchers do this?
The first step towards creation of a real-life model of the human liver was to create an optimal bioink. Previous research of these scientists identified two monomers to use in the bioink. They are called AC4-acryloyl morpholine (ACMO), which provides elasticity and stretchability, and methoxy poly (ethylene glycol) acrylate (mPEGA), which provides softness. The materials are crosslinked by UV-light, which means they are set into place when UV is applied. Digital light processing (DLP) 3D printing is a patterned UV light that is projected from the top onto the bioink. Therefore, the material crosslinks only where the UV light is applied, enabling the 3D printing of a liver. The researchers tested different ratios of ACMO and mPEGA to obtain the liver-like softness and self-healing capabilities at room temperature. After finding the optimal ratios, the researchers used the bioink to 3D print patient-specific livers with tumors using the input from CT scans. Within the bioprinted liver there is room for a tumor, which is bioprinted using a different material. Lastly, the vessels were filled with green paste, resembling the portal vein, and blue paste as hepatic veins. After the tumor and paste are integrated in the bioprinted liver, regular surgical tools such as the scalpel are used by surgeons to operate on the model.
Practice of multiple tumor resections on personalized 3D bioprinted liver.
What comes next?
The future of medical education and surgery could be revolutionized by using 3D-printed personalized liver models. The use of this liver model is used to practice removal of tumors, but can also be used for practice of other intricate liver surgeries, such as liver resections or liver biopsies. However, the technology does not have to stop at livers. This research offers a roadmap to develop 3D printed models of other vital organs, such as the kidneys, pancreas, colon, or stomach. This means future doctors can practice and refine their skills in a safe, controlled environment, leading to better surgical outcomes and fewer complications. By incorporating 3D-printed organs into medical education, we can ensure that surgeons are better prepared for real-life challenges, ultimately improving patient care and safety. This innovative approach represents a significant leap forward in how medical professionals train and prepare for the demands of surgery.