Assessment of anisotropic mechanical response of human skin: insights from a clinical trial

This paper presents findings from the SKin Uncertainties Modeling (SKUM) clinical trial aimed at assessing the anisotropic mechanical response of human skin using the annular suction test, employing a numerical method and a commercial device, CutiScan^® CS 100. A cohort of 30 healthy volunteers participated in the trial, undergoing in vivo testing on the left forearm through a multi-axial stretch induced by ring suction. Determination of the anisotropy axis was performed using a numerical method based on model fitting of experimental data obtained from oriented elliptic curves, which resulted from the radial deformation of circles. The study evaluates the reproducibility and variability of measurements through an intra-subject study involving five participants, providing insights into the consistency of results within individuals. Additionally, an inter-subject analysis across all subjects offers a comprehensive understanding of anisotropy variability, elucidating broader population tendencies. Furthermore, the study explores correlations between anisotropy and demographic factors such as sex, age, and skin thickness, shedding light on potential influences on skin biomechanics. The analysis showed significant correlations between skin anisotropy and sex, with males displaying a distinct anisotropy axis orientation compared to females. In contrast, no significant associations were found between anisotropy and age among individuals aged 20-50, or between anisotropy and epidermal thickness.