Soft Tissue Finite Element Modeling and Calibration of the Material Properties in the Context of Computer-Assisted Medical Interventions

Abstract

International audienceThis chapter aims at illustrating how patient-specific models of human organs / soft tissues can be implemented into Finite Element (FE) packages. First is addressed the question of the generation of patient-specific FE models compatible with the clinical constraints. Then is discussed the calibration of the material properties, with choices that should be done between calibrations based on ex vivo or in vivo tissues loadings. The example of computer assisted maxillofacial surgery is addressed and results based on patients' data are provided

Finite element method for the design of implants for temporal hollowing

“…This assumption may affect the accuracy of the simulation results in terms of stress analysis, but – as the aim of the simulation was to predict the soft tissue displacement – it bears no effect on the implant design pipeline hereby presented. This is also reflected in the good matching between the simulated tissue response and the actual surgical outcomes as shown in Figure 4 C. We acknowledge that a more complex model of the patient upper face (including anatomical sub-structures such as muscles, mucosae and three layers of the skin) 8 and patient-specific tissue mechanical properties 9 would yield more accurate results. 10 Nevertheless, the hereby simplified model provided acceptable results, and the FEM-designed PSI achieved the desired outcomes once implanted ( Figure 1 B,D).…”

Parametrizing the genioplasty: a biomechanical virtual study on soft tissue behavior

“…This is a simplified model which only accounts for the presence of soft and bony tissues without subdividing the former into its main components (fibers, fat, glands, mucosa and three layers of skin). Although the homogeneous tissue assumption has been used in other studies in the past where orthognatic surgery was simulated [19,29] and it is the underlying assumption of preoperative planning commercial softwares such as Materialize Proplan [8,30], a more anatomically accurate representation of the underlying tissues [31][32][33][34][35] would provide a better representation of the elastic response of the lower third soft tissue. Current work in our group is aiming at combining different imaging modalities to overcome the current simplification and provide a more detailed representation of the patient-specific face anatomy [36].…”

“…Current work in our group is aiming at combining different imaging modalities to overcome the current simplification and provide a more detailed representation of the patient-specific face anatomy [ 36 ]. Payan et al [ 34 ] proposed a method for calibrating soft tissue material properties using patient-specific measurements gathered using an aspiration device: our cohort was retrospectively recruited and therefore patient-specific assessment of tissue properties would not be possible. Model validation (reported in Fig.…”