Characterization of human female breast and abdominal skin elasticity using a bulge test.

Abstract

Characterization of material properties of human skin is required to develop a physics-based biomechanical model that can predict deformation of female breast after cosmetic and reconstructive surgery. In this paper, we have adopted an experimental approach to characterize the biaxial response of human skin using bulge tests. Skin specimens were harvested from breast and abdominal skin of female subjects who underwent mastectomy and/or reconstruction at The University of Texas MD Anderson Cancer Center and who provided informed consent. The specimens were tested within 2 h of harvest, and after freezing for different time periods but not exceeding 6 months. Our experimental results show that storage in a freezer at −20 °C for up to about 40 days does not lead to changes in the mechanical response of the skin beyond statistical variation. Moreover, displacement at the apex of the bulged specimen versus applied pressure varies significantly between different specimens from the same subject and from different subjects. The bulge test results were used in an inverse optimization procedure in order to calibrate two different constitutive material models-the angular integration model proposed by Lanir (1983) and the generalized structure tensor formulation of Gasser et al. (2006). The material parameters were estimated through a cost function that penalized deviations of the displacement and principal curvatures at the apex. Generally, acceptable fits were obtained with both models, although the angular integration model was able to fit the curvatures slightly better than the Gasser et al. model. The range of the model parameters has been extracted for use in physics-based biomechanical models of the breast.

Bilayer Stiffness Identification of Soft Tissues by Suction

“…Extensive work has been conducted for decades in order to characterise the elastic properties of soft tissues. The gold standard for ex vivo tissue characterization are based on conventional mechanical characterization technique such as uni or biaxial tensile tests [2][3][4][5][6], pure shear [5,7], plain strain compression [5], bulge tests [8,9], indentation [10,11] or suction [12]. If such traditional mechanical methods proved invaluable, most of them are destructive (the sample needs to be removed from the body) and cannot be used to characterise the mechanical behaviour in vivo (in situ analysis).…”

Non-Invasive in Vivo Quantification of Directional Dependent Variation in Mechanical Properties for Human Skin

“…Therefore, understanding the mechanical behavior of skin at extensive stretching is essential. The bulge test method (Diab et al, 2020;Lakhani et al, 2020;Tonge et al, 2013) can apply load in all directions and overcome the limitation of small deformation but can only be used in ex vivo tests.…”