Payan YohanAssistant Professor, TIMC Laboratory “3D Finite Element Model of the face to predict aesthetic and functional consequences of Plastic and Maxillofacial surgery” A
surgical simulator for plastic and maxillofacial surgery, that gathers
the dental analysis (orthodontia) and the craniofacial analysis (cephalometry)
into a single computer assisted procedure, has been recently presented
and evaluated [1]. This simulator set up a semi-automatic diagnosis
for facial bone structure repositioning. This
talk addresses the next step of this work namely predicting the consequences
of the simulated bone structures displacements on the patient face appearance.
In that purpose, a generic 3D biomechanical model of the human face
was developed [2]. This model is based on a multi-layers volumetric
mesh, used to discretize the linear elasticity equations in the framework
of the Finite Element Method. Biomechanical properties are chosen to
replicate observations made on human skin. Face muscles are defined
in the mesh as separate structures, with different properties (transverse
isotropy, stiffness depending on muscle contraction). Simulations of
face deformations under muscles actions can thus be performed. To
couple the face model with the simulations of bone-repositioning,
the generic soft-tissues mesh is fitted to patient data by elastic
registration, using skull and skin surfaces segmented from a CT exam.
This matching process generates a new model, adapted to the patient
face morphology. Therefore, after correcting the finite elements that
could have been distorted during the registration, the predictions (from
an aesthetic and functional point of view) of the deformations of the
patient face after surgery can be simulated.
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