Stiffness in compression therapy: Analytical estimation of pressure changes beneath textile compression devices

Compression pressure changes in dynamic conditions under textile compression devices have a critical impact on the success of compression therapy. Models exist to predict the level of compression pressure, but not the actual change in pressure. This paper aims to derive a formula to accurately determine the pressure change under textile compression devices, to investigate the factors influencing the pressure change and to verify their effects through theoretical analysis. Firstly, a formula based on Laplace's law is presented which mathematically describes the dependencies of pressure changes. Secondly, a simulation is carried out to demonstrate the effect of these dependencies on pressure changes using theoretical textile curve functions. Finally, the effect of these dependencies is demonstrated by testing short- and long-stretch bandages in a tensile testing machine and using the recorded material curves to simulate a theoretical application of these bandages to the lower limbs. The results show that the change in pressure is not solely determined by the intrinsic properties of the material, but is influenced by several variables, including the mechanical performance of the textile materials during stretching, the target pressures for application of the textile material, and the body geometries to which the material is applied. Pressure change cannot be a constant for textile compression devices such as bandages. The research increases the understanding of the factors that influence pressure changes in compression device materials. The findings may have implications for the design and selection of compression textiles in clinical applications.