Disclosed herein are polyurethane polymer matrices with a porosity of from about 20 microns to about 90 microns that are useful in promoting closure and protection of incision sites； supporting the lower pole position of breast implants； and providing a partial or complete covering of breast implants to provide a beneficial interface with host tissue and to reduce the potential for malpositioning or capsular contracture. The disclosed matrices can be seeded with mammalian cells.
