Researchers:
Prof. Dieter Krause, Jonte Schmiech, Eve Sobirey, Marie Wegner
As part of the COSY-SMILE 2 project, the Institute for Product Development and Mechanical Engineering Design (PKT) supplied numerous models produced using 3D printers. These models eliminate the need for animal testing, ensure high-quality treatment, and enable improved training for surgeons.
It is a race against time. A stroke manifests itself through sudden paralysis or numbness in the face, arm, or leg, speech disorders, visual disturbances, dizziness, unsteadiness, and severe headaches. In such a situation, it is important to call 911 as quickly as possible, because every minute counts. A blood clot blocks the oxygen supply to the brain. “Time is brain,” say experts—the faster the blockage can be removed through surgery, the better the prognosis!
The Institute for Product Development and Design Technology (PKT) at the Technical University of Hamburg, headed by Prof. Dieter Krause, has made an important contribution to enabling doctors to practice the difficult minimally invasive catheter surgery (thrombectomy) more frequently without animal testing. HANNES is the name of the model that replicates the arterial vessels from the groin or wrist to the brain. The acronym stands for “Hamburg Anatomical Neurointerventional Simulation Model.” The model can also be used to practice treating aneurysms (bulges in blood vessels). It works a bit like the well-known skill game “Dr. Bibber” in real life. In Dr. Bibber, plastic organs must be surgically removed from a toy figure with a steady hand. Hannes can be used to practice inserting a microcatheter with a diameter of less than 1 mm from the groin to the brain without turning wrong or damaging any veins.
The individual parts are produced using 3D printing
What sounds like a game can save lives and maintain quality of life. Strokes are one of the most common causes of death and the leading cause of disability. Around 270,000 strokes occur in Germany every year – and the trend is rising. The project is supported by the Federal Ministry of Education and Research (BMFTR) and, initially, by the Medical Technology Research Center Hamburg (FMTHH), a collaboration between TU Hamburg and UKE (University Medical Center Hamburg-Eppendorf). The medical models are being created and adapted by three medical technology doctoral students, Jonte Schmiech, Eve Sobirey, and Marie Wegner.
The individual parts of the model are produced at PKT using 3D printing. They are based on anonymized patient data. Different areas of the model can be exchanged and adapted. This allows different anatomical conditions to be simulated. The printing materials are selected and modified based on feedback from experienced neurointerventionists at the UKE partner institution to ensure that working on the model feels as realistic as possible. Work is already underway to produce even finer branches than before, with a diameter of less than two millimeters. The team is also considering how to depict the venous system and integrate other clinical pictures.
Another advantage of the project is that Hannes can be used for step-by-step learning. This makes it possible to first follow the path of the catheter through the veins directly, and only later is the model covered and orientation is carried out using X-rays. Trainees can also practice the procedure as often as they like until they have mastered it perfectly. And their training success can be measured objectively.
All without animal testing
Hannes is part of the COSY-SMILE-2 (Completely Synthetic Stroke Model for Interventional Development and Education 2) project. The model has been in use at the UKE since 2014. Previously, doctors learned and practiced the procedure on rabbits and pigs. However, their anatomy differs significantly from that of humans. Secondly, the animals had to be anesthetized and then euthanized (killed) for the exercises. The research here follows the 3R motto for animal testing: “Refine, Reduce, Replace.” In this case, the use of animals can now be completely replaced at the UKE. In addition, original instruments can be used for practice, and simple or difficult clinical pictures can be repeated as often as desired.
The PKT is also developing other medical models for use in medical technology. And those involved are not only putting a lot of effort into the material, but also into naming it. BERTA is the name given to the “mouse phantom” used for quality assurance in radiation experiments on small animals: Brave Rodent Phantom. The model allows the use of different dose measurement devices and biological samples and looks deceptively real in CT and micro-CT. This ensures the precise positioning of the animals and the alignment of the radiation. As a result, fewer experiments can be carried out on real animals. An example of the other two Rs: Refine and Reduce.
HUGO, the Hamburg prostate biopsy model, assists in training and quality assurance for fusion biopsy of the prostate in humans. And CHARLIE, a clinical phantom for radiation therapy of the pelvic region, enables significantly more precise irradiation of prostate carcinomas.
The PKT focuses on methods for developing modular product families as well as structural analysis and testing technology. The results are applied in aviation, mechanical and plant engineering, and, of course, in medical technology. The employees and Prof. Krause are proud of their results. "It's easy to forget that Hannes is a medical model – he looks so realistic in practical use. Our models are exemplary for the medicine of the future: it is not only more precise and effective, but also significantly more ethical. Of course, sound basic research is essential – we are particularly interested in findings for development and design in close, interdisciplinary exchange with doctors. This makes it all the more rewarding to always have in mind what all this is ultimately for," says Krause.
Further information:
https://www.tuhh.de/pkt/institut
