INFLUENCE OF THE TEST AREA ON THE MECHANICAL-PROPERTIES OF SKIN

Background: New advances in bioengineering have provided commercially available devices for measuring the mechanical properties of skin in vivo. Reproducibility of data and methodological approaches have not yet been thoroughly studied. Objective: To study the reproducibility and the influence of the area of the test site on the values of biomechanical variables yielded in a normal population. Method: A 500-mbar suction was transmitted to the skin through Cutometer(R) probes equipped with a 2- or 8-mm opening. Results: The best reproducibility was obtained for the maximum distension of skin and for the biological elasticity. The values of the standard biomechanical ratios were almost the same for both probes. Linear correlations were found between parameters of elasticity. Conclusion:The Cutometer is a reliable device. A high degree of correlation exists between biomechanical variables related to elasticity. Under a suction of 500 mbar, both the 2- and 8-mm probes give results which correlate statistically in a large population. However, the two probes do not measure precisely the same aspect of skin mechanics. The 2-mm probe measures the capacity of superficial skin folding, and the 8-mm probe explores the biomechanical properties of the dermis itself and of its slipping mobility on the hypodermis. The biomechanical parameters which appear the most clinically relevant for a normal-looking skin are the maximum distension and the biological elasticity.