Patent attributes
Methods for treating tissue are provided. In one embodiment, an adjunct material, when secured to tissue, can receive at least one physiological element released from the tissue during healing progression of the tissue, and can exhibit first and second stiffnesses in compression that are approximately constant during first and second time periods from contact with the tissue, with the second stiffness decreasing with time as a function of at least one of oxidation, enzyme-catalyzed hydrolysis, and change of pH resulting from interaction with the at least one physiological element. In another embodiment, the adjunct can receive a unit volume of fluid that causes first and second portions of the adjunct to expand according to first and second expansion behaviors that differ from one another to apply different pressures to the tissue.