The Prevalence and Histological Characteristics of the Double Capsule Phenomenon in Breast Augmentation With Implants.

[BACKGROUND] Double capsule formation around breast implants is associated with implant rotation and seroma. However, the prevalence and histological characteristics remain unclear.

[OBJECTIVES] The goal of this study was to quantify the prevalence of double capsule formation of different implant surface textures and explore the histological differences between the inner and outer capsules of breast implant capsule biopsies.

[METHODS] The study was performed with data from the Copenhagen Breast Implant Biobank, comparing the prevalence of double capsule formation around Allergan Biocell implants, Eurosilicone Cristalline implants, and Mentor Siltex implants. The histological characteristics of the inner and outer capsules were analyzed with a validated assessment tool.

[RESULTS] The study included data from 588 patients and 1128 implants. Double capsule formation was found around 25 implants resulting in an overall prevalence of 2.3%. Mentor implants with a Siltex surface had a double capsule prevalence of 0.72%, which was significantly lower than the prevalence for Allergan implants with a Biocell surface (7.8%; P < .001), and Eurosilicone implants with a Cristalline surface (3.4%; P = .03). Histological analysis showed that inner capsules had lower cellular density (P = .04) and were more calcified (P = .03) compared with outer capsules.

[CONCLUSIONS] The risk of double capsule formation was highly correlated with the roughness of the breast implant texture, with the risk of double capsule formation around Mentor Siltex implants being significantly lower than that of macrotextured implants. The histological analysis implies that loss of vascularization to the inner capsule results in a lower cellular density and more frequent calcification.