Testing the Biomechanical Protection by Sacral Border Dressings in a Laboratory-Based Model

Pressure mitigating dressings are one component of pressure ulcer/injury prevention strategies. There are many such devices on the market, but little data to compare them by. Herein we share our results of comparing sacral border dressings' capacity to mitigate deformations due to lateral forces. A modified version of a published digital image correlation-based technique was used to monitor the distortions of a cast silicone sheet under varying loads. Four sacral border dressings were compared to no dressing with three replicates for each. Empirical displacements within the gel were quantified via image analysis and compared via two-way ANOVA followed by Tukey's HSD test. Full field displacements were interpolated from the empirical data and the full field strains and shear were calculated and plotted. All four dressings were statistically significantly different from the control, but not among each other with magnitudes on the order of a hair's breadth. The maximum strains measured among the dressings were not significantly different in the direction of applied force, but two of the dressings were found to differ in the orthogonal direction, and those same dressings had computed strains equal to the control in the direction of the applied force. Our lab-based data indicate that four commercially available sacral border dressings reduce lateral strain under most conditions and shear under all conditions compared to no dressing. While the absence of clear tissue failure criteria limits direct clinical translation, these findings provide a straightforward and quantitative foundation for pre-clinical evaluation of sacral dressings.