Soft tissue response to textured silicone implants in an animal experiment.

In a study on rats to assess soft tissue response to textured silicone implants, ellipsoid 15 x 20 mm pieces from the bag of a Biocell breast prosthesis were implanted under the dorsal skin. Histological examinations including immunohistochemical detection of myofibroblasts were made 2 weeks and 1, 3, 6, and 8 months after implantation (12 specimens for each time interval). On the smooth side of the implant, which served as a control, the thin connective tissue capsule characteristically seen with silicone elastomer implants developed within a month. Myofibroblasts were present after the first month and appeared to reach a peak 3 months after implantation, after which they showed marked regression. On the textured side of the implant, villous processes were a characteristic feature of the capsules; originating in a common basal layer, they penetrated into the cavities of the implant. Collagen deposits and myofibroblasts only became more evident during the third month after implantation; they were limited to the common basal layer of the capsule, though foreign body reaction persisted in the villous processes until the end of the experiment. The experimental study, limited to an 8-month period after implantation, showed that texturing of the implant surface prevents compact capsule development and considerably delays or inhibits the maturation process.