Computer-Assisted 3D-Planning of Hip Operations and Endoprostheses in Bone Tumor Surgery
Introduction
In orthopaedic surgery computer assisted systems are getting more and more important. Due to the complex geometry of the pelvis the exact planning of the hip operation is essential for the operation result. Computer assisted pre-operative planning tools may be used to simulate the results of surgical interventions, to evaluate the consequences of different operation techniques as well as for teaching and education. Furthermore optimal operation strategies, implant positions or implant design can be calculated automatically by means of computer assisted methods.
In this project the software system VIRTOPS (Virtual Operation Planning in Orthopaedic Surgery), that has been developed for virtual preoperative planning and simulation of pelvis and hip operations. The system simulates the endoprosthetic reconstruction of the pelvis for bone tumor patients and supports the individual design of the anatomically adaptable modular prostheses with intramedullary anchorage.
Methods
The software system VIRTOPS is a platform for the 3D planning and simulation of operations in orthopaedic surgery, that opens up new possibilities for the virtual preoperative planning and optimized design of implants in orthopaedic surgery. It supports the different phases of the virtual planning and simulation of hip operations.
In the first step, multimodal image sequences are preprocessed by segmentation and registration algorithms and 3D models of different bone structures and the tumor are generated.
In the virtual environment the surgeon is able to interact with 3D-models by translation, rotation and zooming operations. Furthermore, cutting planes can be positioned interactively. Stereoscopic visualization techniques and 3D input devices support the 3D interaction with the model, especially the precise positioning of cutting planes.
After the resection of the hip the resulting bone surface is used to determine the shape and geometric parameters of the implant resulting in a CAD-model of the anatomically adaptable pelvic prosthesis (Fig. 1). To optimize and validate the position of the implant distances between bone and the anchorage of the CAD-model are computed or the anchorage can be visualized within the hip model in a transparent mode (Fig. 2).
Fig. 1: Upper part of an anatomically adaptable pelvic prosthesis and virtual CAD-model of the prosthesis.
Fig. 2: Resection of the tumorous bone structures (left) and transparent visualization of the bone surface and the intramedullary anchorage.
Selected Publications
Handels, H., Ehrhardt, J., Plötz, W., Pöppl, S.J. Three-dimensional Planning and Simulation of Hip Operations and Computer-Assisted Design of Endoprostheses in Bone Tumor Surgery. Journal of Computer Aided Surgery 2001, 6, 65-76.
Handels, H. Ehrhardt, J., Plötz, W., Pöppl, S.J. Simulation of Hip Operations and Design of Custom-made Endoprostheses using Virtual Reality Techniques. Methods of Information in Medicine 2001, 40, 74-77.
Handels, H., Ehrhardt, J., Plötz, W., Pöppl, S. J. Virtual Planning of Hip Operations and Individual Adaption of Endoprosthesis in Orthopaedic Surgery. Medical Informatics 2000, 58-59, 21-28.
Handels, H., Ehrhardt, J., Peters, P., Plötz, W., Pöppl, S.J. Computer-Assisted Planning of Hip Operations and Design of Endoprotheses using Virtual Three-Dimensional Models. In: Lemke, H.U., Vannier, M.W., Inamura, K., Farman, A.G. (eds.), Computer Assisted Radiology and Surgery, CARS 99, Elsevier, 1999, 726-730.
Project Team
Jan EhrhardtHeinz Handels
Cooperation Partners
Prof. Dr. med. Werner Plötz
Krankenhaus Barmherzige Brüder, München
