Virtual trauma of petrous bone under lateral impact: from medical images to fracture process evaluation
M. Montava,1 S. Bidal,2,* J.-P. Lavieille,1 P.-J. Arnoux3 and C. Brunet3
1 Service ORL et Chirurgie Cervico-Faciale, Hôpital Nord, Boulevard Pierre Dramard, F-13916 Marseille, France
2 Altair Development France, Faculté de Médecine Nord, Boulevard Pierre Dramard, F-13916 Marseille Cedex 20, France
3 Laboratoire de Biomécanique Appliquée, UMR T 24, Faculté de Médecine Nord, Boulevard Pierre Dramard, F-13916 Marseille Cedex 20, France
Head traumas, reported in sport and road accidents analysis, induce complex injuries of petrous bone. Fractures are reported according to a simplified classification, but few works have really investigated injury mechanisms and the potential links between injury description and pathologies (hearing loss, dizziness, face palsy, etc.). In order to provide an evaluation of these injury mechanisms, a finite element model of the petrous bone structure was built. Recent advances in postprocessing of medical images were used to generate an accurate three-dimensional (3D) finite element model of the petrous bone structure from computer tomography (CT)-scan data. Then, a lateral impact of the petrous bone by a surface with an initial velocity of 7 m/s was simulated. Boundary conditions were set in order to take into account the global influence of head structure. Stress distribution analysis during the bone fracture, correlated to the impact chronology, led to a first evaluation of the evolution of the fracture process (longitudinal and transversal fracture modes). Numerical simulation showed a convergence of fracture processes running through the complex geometry of the petrous bone, especially on the external ear and middle ear areas. The map of fracture process was validated using clinical data. These first results are now ready for completion by taking the global head structure more explicitly into account. Further development planned in finite element model creation and numerical analysis, based on medical data, will integrate structure porosity effects and soft tissue components.
Keywords: biomechanics, petrous bone, RADIOSS, virtual trauma