Histopathologic investigation of capsule formation around siliconeimplant after bacterial contamination

Objective: Capsular contracture is a common complication after breast implant surgery. The aim of this study was to compare the histopathologic changes induced by bacteria commonly isolated from the implant environment and their biofilm formation properties after capsular contracture. Materials and Methods: In this study, 4 groups were used: a control group in which sterile silicone materials were implanted in rats (n:11), other three groups in which silicone materials contaminated with Staphylococcus epidermidis ATCC 12228 strain without biofilm formation (n:11), Staphylococcus epidermidis ATCC 35984 strain with biofilm formation (n:11) and Cutibacterium acnes (n:11) were implanted in a total of 44 Wistar rats. The materials removed from the rats 2 months after implantation were examined histopathologically. Results: The capsule thicknesses in the groups using silicone materials contaminated with biofilm-producing Staphylococcus epidermidis and Cutibacterium acnes bacteria were found to be significantly higher than the non-contaminated group (p<0.001, p<0.001). In cytologic examination, the number of macrophage-histiocytes was found to be significantly higher in the group contaminated with Staphylococcus epidermidis, which is capable of producing biofilm layer, than in the group contaminated with Staphylococcus epidermidis, which is not capable of producing biofilm layer, and in the sterile group (p=0.045, p=0.001, respectively). Conclusion: This study shows that contamination of the surface of silicone implants with biofilm-forming bacteria (Staphylococcus epidermidis ATCC 12228, Cutibacterium acnes ATCC 6919) has a great effect on the thickness increase in the pericapsular tissue. In our study, the number of macrophage-histiocytes around silicone materials contaminated with Staphylococcus epidermidis ATCC 35984 strain was higher than the other groups. In order to prevent the increase in capsule thickness, which is a histopathologic finding suggestive of capsular contracture, it is necessary to prevent the contamination of bacteria associated with the biofilm layer during and after surgery, and to prevent the number and activation of macrophage-histiocytes in the pericapsular tissue.