Tissue effects of new silicone mammary-type implants in rabbits.

Two new types of silicone mammary-type implants designed to reduce silicone leakage by a gel barrier or to insulate tissue from silica in standard implants (by silicone coating) were placed in rabbits. Standard-type silicone implants were placed as controls. Capsules histologically similar to those that occur in humans occurred around many implants, although no grossly visible capsular contraction occurred. Inflammation was minimal around all types of implants, and the capsules appeared similar. Myofibroblasts were seen around implants within the first three weeks only. Scanning electron microscopy with energy-dispersive x-ray analysis was used to positively identify silicon in tissues around the implants. Silicon was found in tissues from 55% of the standard and 60% of the silicone-coated implants, while it was found in only 10% of capsules around implants containing a gel barrier layer. We conclude that both kinds of new implants incite minimal reaction in rabbits, and that a gel barrier can reduce silicone leakage from silicone implants.