A medical implant with an external surface layer of silicone elastomer and having an open-cell structure is made by applying solid particles to the external surface layer of the implant before it is cured, curing the external surface layer with the solid particles embedded therein and then dissolving...http://www.google.com.au/patents/US4889744?utm_source=gb-gplus-sharePatent US4889744 - Method for making open-cell, silicone-elastomer medical implant
