Long-term Insights: Histopathological Assessment of Polyurethane Implant Capsules Over 24 Years

Polyurethane (PU)-coated breast implants are known for their strong integration into breast tissue and the formation of capsules around them. However, capsular contracture can pose both aesthetic and clinical challenges.

The objectives of this study were to analyze the biological and morphological characteristics of the capsular tissue surrounding PU-coated implants, irrespective of their contracture status, and to assess their potential suitability as a flap in revisional breast surgery for capsular contracture.

A total of 23 tissue samples were harvested from the capsules surrounding PU-coated breast implants in 12 female patients during replacement or revisional surgery. We evaluated collagen abundance, cellular and vascular density, inflammation, collagen band types and alignment, synovial metaplasia, capsule thickness, and the expression of inflammatory biomarkers and myofibroblasts with immunohistochemical techniques. Scanning electron microscopy was employed to assess implant surface characteristics over time.

We found a significant association of capsule contraction with longer implantation durations and greater implant surface roughness (P = .018 and P = .033, respectively). Synovial metaplasia was significantly more frequent in noncontracted capsules (P = .0049). Both capsule types consisted of paucicellular, type I collagen-rich compact fibrous tissue with low vascularization. There was a marked reduction in inflammatory cells within the foreign body granuloma. The expression of inflammatory biomarkers in the capsular tissue was negligible.

Given the reduced levels of inflammatory and vascular components within the dense, fibrous capsular tissue, we consider them to be viable alternatives for capsular flaps in revisional surgery. This strategy has the potential to mimic the reconstruction achieved with acellular dermal matrix.