Operating on hips in a virtual operating room
Each year, more than 200,000 people receive a prosthetic hip in Germany. The success of these operations has a major impact on the quality of life of those affected. However, the procedure is often difficult, particularly the step that involves the so-called milling out of the acetabulum, one of the most delicate and difficult steps to practice. This is where the project “HüftImplantatPfannenfräsSimulator” (HIPS) steps in.
The project, successfully completed in April 2019, was led by the Professorship Machine Tool Design and Forming Technology at Chemnitz University of Technology. The Center for Computing Technologies (TZI) at the University of Bremen provided research expertise in the field of virtual reality. Also involved in the project were FAKT Software GmbH in Leipzig and CAT Production GmbH in Munich.
The scientists are currently planning the further development of the system, in order to be able to map additional surgical procedures. Aspiring surgeons should then be able to train on procedures such as the separation of the femoral head, the scraping of the femur, and the implanting of the artificial joint, all in virtual reality. “With the successful completion of HIPS, we have developed the world’s first surgical VR system for non-minimally invasive operating procedures with haptic feedback. However, this success is only a first step, and as a team, we are motivated to make additional procedures trainable using VR,” says Mario Lorenz from Chemnitz University of Technology, initiator of the cooperative project.
Robotics provide a realistic feeling
Hip implants must fit as accurately as possible in the acetabulum, in order to avoid complications and maximize the life of the prosthetic. The corresponding operation is quite complex, and requires a lot of power, along with great precision. Adding to this challenge, the site of the operation is barely visible to the surgeon. So far, it has been hardly possible to practice this procedure under realistic conditions.
Users of the HIPS system use VR glasses to see the hip of the virtual patient, while at the same time operating a milling machine that is connected to a robotic arm. The robot provides realistic haptic feedback, for example, by providing virtual resistance that would normally take place on the bone during the milling process. “Real data provides the basis for this realistic simulation,” explains Prof. Dr Gabriel Zachmann from the University of Bremen. “In order to gather the data, we precisely measured the milling process and developed corresponding algorithms.” FAKT Software GmbH integrated the resulting software modules into an interactive application that is based on an anatomical 3D model provided by CAT Production GmbH.
Background: HIPS
The „HüftImplantatPfannenfräsSimulator“ (HIPS) project ran for a period of three years. The BMWi sponsored the HIPS project with a total of around 670,000 euros within the scope of the network “Kunstgelenk-Netzwerk Endoprothetik”. A virtual reality simulation with the help of a robotic arm makes it possible to practice this hip joint implantation procedure in a realistic manner. Thus, the HIPS system facilitates the preparation of future surgeons for real-time situations.
Taking part on the medical side of the project are the Department of Orthopedics, Trauma Surgery and Plastic Surgery at the University Hospital Leipzig, the Center for Research on the Musculoskeletal System (ZESBO) at the University Hospital Leipzig, the Department of Anatomy at the University of Otago (New Zealand), and the Medical Technology Department of the Fraunhofer Institute for Machine Tools and Forming Technology (IWU).
