3D printing offers significant advantages for preoperative planning in the medical field. However, due to the high cost of industrial-grade printers, not to mention the difficulty of acquiring the software,
it has not been widely adopted.
Jan Witowski, along with a research team from Jagiellonian University, has developed a method to use a desktop 3D printer to create human liver models for use before complex surgeries. Preoperative models (or what are known as preoperative guides) are particularly useful in surgeries that require accurate anatomical visualization.
They believe that this approach offers several benefits over standard imaging techniques, such as shorter surgery and recovery times, reduced blood loss, and better resection margins.
Challenges Faced by Doctors
When performing laparoscopic liver resections, it is crucial to know the exact location of the tumor and nearby blood vessels to reduce the risk of excessive blood loss during surgery.
This is a minimally invasive procedure, and surgeons are keen to explore new ways to improve surgical preparation. However, according to the latest literature, only 10 cases worldwide have involved doctors using 3D printing as part of their preparation process. The biggest question is, what is stopping them from using this technology?
As Witowski points out in his paper, conventionally, the main factor preventing surgeons from using 3D printing is cost.
Industrial-grade 3D printers cost over $200,000, and few medical professionals at medical institutions would use them.
Additionally, specialized software costs thousands of dollars, and these are all costs that few practitioners are willing to bear. Until recently, most liver models
were created using material jetting (Polyjet / Multijet), with each model costing up to $5,000.
Another significant factor preventing surgeons from adopting 3D printing technology is time. Developing a model using industrial-grade 3D printers takes four to seven days.
Outsourcing takes even longer.
Witowski also emphasizes that SLA and SLS are unsuitable because surgeons would lose the ability to visualize the parenchyma (the external shape of the liver). His goal
is to provide an alternative that uses FDM printers and silicone, which would reduce manufacturing costs significantly while retaining all the details needed to improve the surgical process.
Using Ultimaker 3D Printers to Create Liver Models
Using a desktop 3D printer to 3D print liver models reduces the total time by approximately 60-100 hours. The price is also considerably lower. Witowski illustrates how it
works with a chart.
The 52-year-old female patient first underwent laparoscopic colorectal resection and two years later underwent laparoscopic right hemihepatectomy (secondary liver resection),
after a CT scan revealed a single metachronous metastasis.
Her CT scan clearly showed the cross-sectional structure, and then the virtual model was converted into an STL file and 3D printed.
For 3D printing, Witowski used Blender, Meshmixer, and Ultimaker Cura, along with an Ultimaker 2+ 3D printer.
Model Development Stage
Model development consists of four key stages: object segmentation, common 3D model computer processing, slicing and printing, and finally silicone curing, followed by finishing and assembly.
The total printing time ranges from 60 to 100 hours, depending on the model's size, the number of parts, printing accuracy, and printer type. In this case, 72 hours of printing were required,
and due to material interchangeability and print platform size, it had to be executed in six print jobs.
Post-processing is important to maximize the smooth quality of the silicone surface and prevent cloudiness. The model is sanded with 100-300 grit sandpaper, then washed with water and dried.
It is then coated with XTC-3D self-leveling resin, allowed to cure for about 3 hours until the resin dries, and then this process is repeated to ensure the surface is sufficiently
smooth for silicone casting.
Regular cyanoacrylate-based adhesive is used to bond multi-part structures, then protected at the connection areas with electrical tape and modeling clay to prevent
silicone leakage during the casting stage.
Results
Thanks to Ultimaker, Witowski was able to create a clear, full-size liver model, showing blood vessels and malignant colorectal cancer metastases, for less than $150. This was achieved using a combination of 3D printed models and silicone casting molds.
Desktop 3D printers like Ultimaker can be placed immediately in the hospital and produce physical models of patient anatomy in a matter of hours or days.
This allows surgeons to touch and feel the model, making the process of planning the surgery more realistic.
Jan concludes: “I chose Ultimaker because of its reliability.I need a printer that won't fail me when I'm printing several 20+ hour print jobs day after day.I truly believe that using low-cost printing is a huge step towards personalized medicine.I’ll definitely continue using Ultimaker,
especially for high-impact projects where I need to be sure to provide results on time.”
Costs and Timing
Using traditional techniques to create models, the estimated cost is about $1,000 for a liver model and $500 for a kidney model.
Cost comparison between fabrication methods
Labor costs and costs associated with 3D printer operation were neglected, as Witowski did not require extra staff (experts, technicians, computer graphics, etc.) for execution.
Using FDM methods, the model was created within five days.
Surgeons were then able to explore the models visually and tactilely, helping them create an operative plan.
Wider Implications
By adopting 3D printing across the departments of Vascular Surgery, Cardiac Surgery, and Urology, Jagiellonian University hosts the largest 3D printing research
center in Poland and consults doctors across the country.
Jan and his team have proven that 3D printing is not just a trend, but a true medical tool. The department is excited to
work further with FDM technology while exploring its wider benefits.
Surgical guidance, training for medical students, and demonstration models for patients provide doctors and patients alike with greater understanding and peace of mind.
“I firmly believe that using low-cost printing is a huge step towards personalized medicine.”
Most recently, Jan and his team printed a model of pulmonary arteries for cardiologists in Otwock, Poland, for use in balloon pulmonary angioplasty—a process to widen narrow or obstructed arteries or veins. Reports show that using these models reduced operative time, improved short-term outcomes, and significantly assisted with planning.
It’s likely to be only a matter of time before medical practices start more widely adopting desktop 3D printing technology and making the most of its benefits.
Disclaimer: Ultimaker 3D printers are designed and built for fused deposition modeling with Ultimaker engineering thermoplastics within a commercial/business environment.
The combination of precision and speed makes Ultimaker 3D printers the perfect machine for concept models, functional prototypes, and the production of small series. Although we achieved a very high standard in the reproduction of 3D models using
Ultimaker Cura, the user remains responsible for qualifying and validating the application of the printed object for its intended use, especially critical for applications in strictly regulated areas like medical devices
and aeronautics.
Original link:https://ultimaker.com/en/stories/39791-3d-printing-a-cost-effective-personalized-liver-model-for-preoperative-planning