Abstract: An implantable medical device includes a porous metal foam or foam-like structure having pores defined by metal struts or webs wherein the porous structure has directionally controlled pore characteristics. The pore characteristics controlled include one or more of the metal structure porosity, pore size, pore shape, pore size distribution and strut thickness. The pore characteristics may vary in one or more directions throughout the structure. Preferably the pore characteristics are controlled to match the porous metal structure to various mechanical and biological requirements of different regions of the structure in order to optimize aspects of the implants performance and may vary not only over the surface of the porous structure but through the depth of the porous structure. The thickness of the porous metal structure may also be modified to establish a thickness profile that optimizes mechanical and biological requirements of the implants performance.

Abstract: The invention relates to implantable medical devices, particularly, to porous structures for such devices. In one aspect, the invention provides a porous metal scaffold comprising a porous metal network having pores defined by metal webs, the metal webs covered with at least one layer of metal particles bonded to the metal webs. In other aspects, the invention provides methods of forming porous scaffolds. In one such aspect, the method includes providing a polymer foam; forming a skin of biocompatible metal on the polymer foam by low temperature arc vapor deposition; and heating the polymer foam and the metal skin above the decomposition temperature of the polymer foam in an inert gas atmosphere; thereby the polymer foam decomposes producing a green metal foam. In yet other aspects, the invention provides methods of improving stability of porous scaffolds.