US Patent 9724203 Porous tissue ingrowth structure

A three-dimensional scaffold for a medical implant includes a plurality of layers bonded to each other. Each layer has a top surface and a bottom surface and a plurality of pores extending from the top surface to the bottom surface. Each layer has a first pore pattern of the pores at the top surface and a different, second pore pattern at the bottom surface. Adjacent surfaces of at least three adjacent layers have a substantially identical pore pattern aligning to interconnect the pores of the at least three adjacent layers to form a continuous porosity through the at least three adjacent said layers.