Entwicklung eines interaktiven VR-basierten chirurgischen Simulators zum Training der bilateralen sagittalen Spaltosteotomie

• Applicants: Professor Dr.-Ing. Thomas-Peter Fries; Privatdozent Dr. Marcus Gerressen; Professor Dr. Torsten Wolfgang Kuhlen
• Subject Area: Medical Physics, Biomedical Technology
• Term: from 2009 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 80893132

• Final Report Year: 2013

Final Report Abstract

The different components, i.e. simulation, visualization and haptic rendering are combined together to form a virtual simulator of the BSSO. The employed and newly developed approaches are thereby carefully chosen to transfer the benefits of the XFEM, i.e. the avoidance of any remeshing, to the other components and to minimize the efforts needed to keep the representations consistent. To allow a realistic interaction with the simulated scenario an algorithm for a bimanual force and torque feedback was developed. Here, an existing approach was extended to allow a bimanual interaction and to simulate friction between the objects. Additionally, a generic haptic rendering approach was developed and evaluated which increases stability and enhances the clarity in which the virtual scene is felt. Furthermore, a software concept for concurrent interactive simulation architectures was developed and implemented in a separate software module making it reusable also for other scenarios. On this basis a specific architecture was developed for the BSSO simulator integrating all components into one interactive application. In this, several components are further parallelized like the collision detection and the setup of system of equations used during the haptic rendering. The overall parallelism thereby allowed to fullfill the necessary requirements on update rates. A formal analysis of the BSSO procedure was carried out based on a proven method. The results concentrate knowledge from expert surgeons and the literature into an easy accessible form and allowing reliable knowledge transfer to the non-medical partners. In the course of the project several experiments have been conducted, on the one side for the determination of mechanical properties of the mandible, i.e. for the breaking and sawing simulation, and on the other side for a fundamental investigations of multimodal interaction in case of drilling and/or sawing like tasks. In the scope of this project, a novel approach to three–dimensional crack propagation using the XFEM was developed. The new approach relies on a hybrid explict–implicit description of the crack which maintains the advantages of the explicit description using a geometric representation of the crack and the implicit description using level set functions. In addition, new propagation criteria were introduced in the context of the XFEM and the most favorable (MSERCC) was employed in the simulator.

Publications

• Der Einfluss der BSSO auf die Gelenkfunktion bei Patienten mit skelettaler Klasse II - eine prospektive klinische Studie. Kongressband der 48. Jahrestagung der DGPW, Leipzig, 2010
  M. Gerressen, A. Ghassemi, R. Hilgers, D. Riediger
  
• Design of an Interactive Virtual Reality-based Surgical Simulator for Training of Bilateral Sagittal Split Osteotomy. International Journal of Computer Assisted Radiology and Surgery (Special Issue): Proceedings of the 24th International Congress and Exhibition, 2010
  T. Knott, S. Ullrich, M. Baydoun, J. Saxe, T. Fries, M. Gerressen, T. Kuhlen
  
• Medical training simulators for bilateral sagittal split osteotomy and regional aneasthesia in virtual environments. Jahrestagung der Deutschen Gesellschaft für Computer- und Roboterassistierte Chirurgie (CU- RAC), Düsseldorf, 2010
  T. Knott, S. Ullrich, O. Grottke, T. Fries, M. Gerressen, T. Deserno, R. Rossaint, T. Kuhlen
  
• Dissecting in Silico: Towards a Taxonomy for Medical Simulators. Medicine Meets Virtual Reality 18 - NextMed, 2011
  S. Ullrich, T. Knott, T. Kuhlen
  
• Influence of the bimanual frame of reference with haptics for unimanual interaction tasks in virtual environments. 3D User Interfaces, 2011
  S. Ullrich, T. Knott, Y. Law, T. Kuhlen
  
• Practical methods for designing medical training simulators. Medicine Meets Virtual Reality 18 - NextMed, 2011
  T. Knott, S. Ullrich, T. Kuhlen
  
• Comparing Auditory and Haptic Feedback for a Virtual Drilling Task. Joint Virtual Reality Conference of ICAT - EGVE - EuroVR, 2012
  D. Rausch, L. Aspück, T. Knott, S. Pelzer, M. Vorlünder, T. Kuhlen
  
• Crack propagation criteria in three dimensions using the XFEM and an explicit–implicit crack description. International Journal of Fracture, 105, 161–186, 2012
  M. Baydoun and T.P. Fries
  (See online at https://doi.org/10.1007/s10704-012-9762-7)
• Crack propagation with the XFEM and a hybrid explicit-implicit crack description. International Journal of Numerical Methods in Engineering, 89, 1527–1558, 2012
  T.P. Fries and M. Baydoun
  
• Failure mode and effects analysis in designing a virtual reality-based training simulator for bilateral sagittal split osteotomy. International Journal of Medical Robotics and Computer Assisted Surgery, 2013
  R. Sofronia, T. Knott, A. Davidescu, T.Kuhlen, M. Gerressen
  (See online at https://doi.org/10.1002/rcs.1483)