Identification of the material parameters of soft tissues in the compressed leg

Abstract

Elastic compression is recommended in prophylaxis and the treatment of venous disorder of the human leg. However, the mechanisms of compression are not completely understood and the response of internal tissues to the external pressure is partially unknown. To address this later issue, a 3D FE model of a human leg is developed. The geometry is derived from 3D CT scans. The FE model is made up of soft tissues and rigid bones. An inverse method is applied to identify the properties of soft tissues which are modelled as hyperelastic, near-incompressible, homogeneous and isotropic materials. The principle is to calibrate the constitutive properties using CT scans carried out with and without the presence of a compression sock. The deformed geometry computed by the calibrated FE model is in agreement with the geometry deduced from the CT scans. The model also provides the internal pressure distribution, which may lead to medical exploitation in the future.

Keywords:

• soft tissues
• elastic compression
• mechanical identification
• FE model
• constitutive properties

Acknowledgements

The authors are grateful to the Rhone-Alpes Regional Council for funding the Ph.D. grant of L.D and to the ANR (French National Research Agency) for its support. J.-F. Pouget and the Clinique Mutualiste de Saint-Étienne are gratefully acknowledged for their help with medical images, and BVSport^© for providing and characterising the socks.