Histological analysis of capsule formation around silicone implants and comparison with titanium-coated silicone implants in rats

Silicone implants have been used for breast augmentation for more than 45 years. Complications, in particular capsular contracture, occur with an incidence of <10% and up to 60%. We investigated the influence of the surface of breast implants on the formation of capsular contracture by comparing silicone with titanium-coated silicone. Seventeen smooth saline-filled silicone (group A) and 14 saline-filled titanium-coated silicone (group B) implants were implanted in female Wistar rats. After 12 and 36 weeks, the implants and capsules were extracted; histological and immunohistochemical staining was performed. The evaluation of the capsules was performed by two examiners in a double-blinded manner. Histologically, no significant difference in total capsule thickness was found. There was a significant difference in synovial-like metaplasia layer (SLM) thickness between groups A and B (p=0.041). Regarding implantation time (12 vs. 36 weeks), a significant difference was found in SLM thickness (p=0.021). Immunohistochemical staining indicated a significantly lower infiltration with inflammatory cells in group B. A significant correlation (p=0.019) between a thick SLM layer and inflammatory cell infiltration was detected. Titanium-coated silicone implants reduce SLM thickness and capsular inflammatory cell infiltration. These findings postulate that titanium-coated silicone implants might point out a new chance in the prevention of capsular contracture.