Histological analysis of silicone breast implant capsules and correlation with capsular contracture

Background: A study was undertaken to investigate long-term histological changes in the environment of breast implants and their correlation with complains at the time of capsular contracture defined by the Baker score. Method: The collagenous capsules of 53 silicone breast implants from 43 patients (23 smooth and 30 textured devices) were evaluated histologically for capsular thickness, the presence of histiocytes, the amount of silicone and calcification in the capsule, and the presence of synovial-like metaplasia of the inner surface of the capsule with light microscopy and polarised light. All parameters were correlated with the Baker score. Results: A significantly higher degree of the Baker score was found with increasing patient age (p<0.001), implant duration (p<0.02), and capsular thickness (p<0.009). A trend towards greater capsular thickness was documented in patients who had a breast augmentation for cosmetic reasons. Synovial-like metaplasia was seen in 28 capsules (52.8%). The highest incidence was found in textured implants with a duration of less than 5 years. Histiocytic inflammation was more common in patients with clinical symptoms (p<0.001) and around subglandular implants (p<0.096). Conclusions: The histological findings of breast capsules were related to: the nature of the device surface (smooth versus textured), implant duration, and the degree of capsular contracture. Capsular contracture (Baker score of 3 or 4) was related to implant duration, capsule thickness, patient age, and inflammation.