In the maze-like corridors at the University Hospital of Lübeck, one of the biggest in Germany, you can easily lose any sense of direction, time and space. The future of medical technology is just next door, in the 3D printing lab of the Institute of Neuroradiology, headed by Professor Peter Schramm. This is where Dr. Kemmling, staff neuroradiologist and researcher is using highly precise stereolithography (SLA) 3D printing to create models of brain arteries with the Formlabs Form 2 3D printer. This allows him to personalise operations and reduce associated risks including stroke.
After years of experience with emergency procedures, Dr. Kemmling knows that performing endovascular surgery is not only a matter of time, but also precision: Millimeters can decide the difference between death and life . The most advanced medical devices will only work correctly when accurately placed.
By 3D printing 1:1 replica brain arteries from patients' CT scans, Dr. Kemmling provides a universal tool for research and training purposes, creating a highly affordable, anatomically correct alternative to silicone models and animal testing. His vision is to provide personalised treatment plans for all patients globally.
Personalised Treatment for Aneurysm Patients
An aneurysm is a balloon like bulge filled with blood that creates a widening of the cerebral arteries, effecting up to 3 percent of the general population. The larger and more complex the aneurysm, the more likely it is to burst open without warning, resulting in acute bleeding in the brain. Once ruptured, an aneurysm will cause death in 30% of cases and permanent disabilities for an additional 30%.
In most cases, aneurysms are discovered by accident from MRI or CT scans, but not every aneurysm needs to be treated. The question is often: should the patient take on the risk of preventive treatment, or leave it, knowing the aneurysm could burst open at any time, leading to a potentially serious outcome?
In the operating room with Dr. Kemmling and his team treating an aneurysm after testing with a 3D printed model.
With today's technology, preventive endovascular surgery is possible with high tech devices such as flow diverters. These are microscopic woven wire frames that inhibit blood flow into the aneurysm, eventually making it disappear. Flow diverters must be precisely placed inside the fine brain arteries with micrometer precision. There are no second chances. Once the flow diverter expands within the artery, it can not be adjusted without significant risk.
Using Dr. Kemmling’s innovative method, doctors can produce and use accurate physical replicas of patients’ brain arteries to practice procedures beforehand with the exact same tools used during endovascular surgery, minimising risk and verifying that the procedure will work in the operating room.
Practice also reduces the time spent in the operating room by up to 50 percent, from 30-50 minutes with no training, to 25-15 minutes with repetitive training using a 3D model, further minimising risks for the patient.
Using 3D Models for Brain Operations
Dr. Kemmling in his 3D printing lab, testing operation devices on the 3D printed aneurysm of a patient.
“How do you become a neuroradiologist? You watch others for years, but at some point, you have to go inside the brain,” said Dr. Kemmling. He considers the fast and flexible production of 3D models a greatly needed solution for bridging the gap from learning how to perform procedures, to actually performing procedures.
Dr. Kemmling was one of the first to purchase the Form 2 SLA 3D printer in Germany., allowing him to print a set of eight aneurysm cases within two days. Silicone models, using a molding procedure, have a lead time of several weeks and do not provide the same level of anatomic details of the 3D models.
Printed with Formlabs Clear Resin, Dr. Kemmling's models have a resolution of 0.025 mm. which is less than the width of human hair. By standardising his method with 3D printing, Dr. Kemmling wants animal testing to vanish.
By showing patients a 3D printed model of their brain, Dr. Kemmling can effectively communicate the procedure with the patient.
“When telling patients that it is possible to prepare the treatment with their specific anatomy, they are reassured,” Dr. Kemmling said.
“This is what your aneurysm looks like, this is where we have to go in, this is what we are going to do. With 3D printing being so affordable and easy to produce, patients can even take their models home.”
Taking Your 3D Printed Brain Arteries Home
Christine was diagnosed with an aneurysm after getting a routine MRI scan to investigate a persistent headache. Having never heard of aneurysms before, she was not immediately aware of the severity of her situation.
Dr. Kemmling and his patient Christine, looking at her 3D printed aneurysm after successful treatment.
“I did not panic before I saw how shocked my friends were,” Christine said.
When Dr. Kemmling showed Christine the 3D printed brain model printed from her scan, she was surprised by how small the aneurysm was. With the help of the 3D model, Dr. Kemmling explained and demonstrated the procedure with the equivalent tools on a 1:1 scale model.
Christine was able to take the model home and show family and friends to communicate the problem and how the treatment would work.
“I was impressed by the level of precision; not even an embroiderer could produce such fine details,” Christine said. “I did some further research and then decided that I would choose to go all the way through the artery for treatment of the aneurysm.”
The alternative option was to perform a classic open brain surgery with a much longer recovery period. In contrast, endovascular treatment of the brain artery is far less invasive for the patient, who usually can be discharged from the hospital within a few days. For Milius, this procedure took no longer than 30 minutes, a precise and time-efficient operation where the doctor was prepared with the 3D model.
The Future of 3D Printing in the Medical Field
Christine has recovered and is healthy today. The latest tests have confirmed that the implanted flow diverter worked and her aneurysm has totally disappeared.
Dr. Kemmling has treated over 100 patients at his clinic in Lübeck. While this number is still too small to compare with the long-term success rate of alternative treatments, Dr. Kemmling can confirm that performing endovascular operations on brain aneurysms is faster and more secure following training and practise with 3D printed medical models.
The team of the Institute of neuroradiology gives regular workshops both in the 3D lab and at international courses, to share their knowledge with fellow neuroradiologists.
Dr. Kemmling has inspired more 3D printing applications in the medical field, with another research group now using 3D models printed in Dr. Kemmling’s 3D labs to test medication for blood clotting.
In Dr. Kemmling’s view, 3D modeling and 3D printing are easily adaptable for a broad range of procedures within the medical field. Generally, 3D models can be used for experimental measurement in order to see how devices can be integrated into the body and how they impact blood flow, making them relevant to many clinical areas.
A display of 3D artery models in various sizes, printed with Clear Resin and a 0.025 mm resolution.
Medical professionals around the world are quickly adopting personalised medical procedures using emerging technologies such as 3D printing. Produced at a significantly lower cost and in substantially less time, 3D printed medical models are now replacing silicone models and animal testing. Dr. Kemmling’s method is replicable by any doctor with a 3D printing lab and the ambitions to treat every patient individually.