Although 3D printing has become more popular in the last decade, few hospitals are printing by themselves. The Elisabeth-Tweesteden Hospital in Tilburg, the Netherlands, has purchased two 3D printers—the Makerbot Replicator Z18 and the Ultimaker 3—in the past year. The hospital, a Level-1 trauma center with a large neurosurgical department, aims to service 75% of all major trauma patients in the area. The trauma center’s 3D printing system focuses on bone structures and aims to help trauma surgeons better prepare for complex fractures.
Taking a Closer Look
The 3D printing lab is directed by trauma surgeon Mike Bemelman, MD, and Lars Brouwers, MD, MSc, PhD-candidate. Their goal is to provide all surgeons and residents with 3D-printed anatomical models to help with surgical preparations, understand fracture patterns, and determine optimal surgical approaches. “The beginning of our 3D-printing process was difficult, because we had to find out which printers were suitable for medical 3D printing,” says Dr. Brouwers. “Furthermore, we had to determine how to convert CT files into 3D printing files called stereolithography (STL) files.” The team purchased two poly lactic acid (PLA, one of two major material types used in 3D printing) printers because of the affordable raw plastics and the simplicity of the printing process. “The added value is immense,” says Dr. Bemelman. “We can also pre-bend titanium plates on the 3D-printed models to reduce operation time.”
To make this solution available to all patients, work-flow in the 3D printing lab had to be economically sound, without the need for a technician. Using in-hospital software from Philips, Drs. Brouwers and Bemelman convert CT data into STL files and use open-source software (Meshmixer and Simplify 3D) to prepare the STL files for printing. This workflow takes 10 to 15 minutes, and the plastic prints cost approximately $5 to $10, depending on the size of the model. A life-size wrist model takes approximately 4 hours to print, and a pelvic model requires 24 hours.
“Although we use the 3D-printed models as a reference during operations in a sterilized plastic bag, we prepare surgical guides for corrective osteotomies using Selective laser sintering printing, which uses a laser to precisely fuse nylon powder into lightweight, robust parts,” notes Dr. Brouwers. “This printing is outsourced to a commercial company while surgical guides are also prepared in-house using PLA, which allow surgeons to practice difficult operations, in turn reducing operation time.”
“Many physicians state that medical outcomes are improved by the use of 3D printing, though only 14% of medical papers support this statement with hard metrics,” says Dr. Brouwers. Still, he is convinced that 3D printing is of added value. Together with trauma surgeon Koen Lansink, MD, PhD, MSc, he conducted a study to test the added value of 3D printing and virtual reality in understanding acetabular fractures and presented the results at the 2017 European Society for Trauma & Emergency Surgery annual meeting. For the study, several participants had to classify 20 acetabular fractures using X-ray/2D CT, 3D CT, 3D prints, and virtual reality. Using X-ray/2D CT, only slight and fair agreements were found between the observers. However, substantial agreements were found among those using 3D-printed models (Figure). Using virtual reality, observer agreement among senior trauma surgeons decreased, while observer agreement among younger participants increased with the use of virtual reality. Dr. Brouwers says, “The study findings suggest that medical students can classify an acetabular fracture as well as the head of the trauma department of an academic hospital using 3D-printed models or virtual reality. The learning curve to identify fracture patterns is shortened by 20 years of experience, and students can step in at a higher level than they did 20 years ago.”
Innovation Is Imperative
Alongside vascular surgeon Jan Heyligers, MD, PhD, Bemelman and Dr. Brouwers are exploring the future of 3D printing use in surgery. “We recently installed VPI Reveal stereoscopic 3D visualization systems in our trauma rooms to ensure real-time 3D views of trauma patients,” says Dr. Heyligers. “Neuro-, maxillofacial, vascular, and trauma surgeons are already using the system to learn more about complicated brain lesions, fractures of the face, aneurysms, and complicated fractures that require immediate surgery, changing the way physicians think about crucial anatomic patterns.”
All three physicians believe that innovation is imperative, it is important to educate patients in the best possible ways, and 3D printing and augmented reality are going to play major roles in hospitals in the near future.