A reduced-pressure system for treating a tissue site on a patient includes a distribution manifold that adheres to a tissue site to allow retention without external support. The distribution manifold includes a porous member and a tissue-fixation element. The tissue-fixation element maintains the porous member substantially adjacent to the tissue site while a sealing member is applied. In one instance, the tissue-fixation element is a soluble adhesive that partially covers either the tissue-facing side of the porous member or a tissue-facing side of a fluid-permeable substrate layer that is on the tissue-facing side of the porous member. Other systems, distributions manifolds, and methods are presented.