Polyurethane breast implants were first introduced by Ashley (Plast Reconstr Surg 45:421-424, 1970), with the intention of trying to reduce the high incidence of capsular
contracture associated with smooth shelled, high gel bleed,
silicone breast implants. The sterilization of the
polyurethane foam in the early days was questionable. More recently,
ethylene oxide (ETO)-sterilized
polyurethane has been used in the manufacturing process and this has been shown to reduce the incidence of biofilm. The improved method of attachment of
polyurethane onto the underlying high cohesive gel, barrier shell layered,
silicone breast implants also encourages bio-integration.
Polyurethane covered, cohesive gel,
silicone implants have also been shown to reduce the incidence of other problems commonly associated with smooth or textured
silicone implants, especially with reference to displacement, capsular
contracture,
seroma, reoperation, biofilm and implant
rupture. Since the introduction of the conical
polyurethane implant (Silimed, Brazil) into the United Kingdom in 2009 (Eurosurgical, UK), we have had the opportunity to review histology taken from the capsules of
polyurethane implants in three women ranging from a few months to over 3 years after implantation. All implants had been inserted into virgin subfascial, extra-pectoral planes. The results add to the important previously described histological findings of Bassetto et al. (Aesthet Plast Surg 34:481-485, 2010). Five distinct layers are identified and reasons for the development of each layer are discussed. Breast
capsule around
polyurethane implants, in situ for fifteen and 20 years, has recently been obtained and analysed in Brazil, and the histology has been incorporated into this study. After 20 years, the
polyurethane is almost undetectable and capsular
contracture may appear. These findings contribute to our understanding of
polyurethane implant safety, and give reasoning for a significant reduction in clinical capsular
contracture rate, up to 10 years after implantation, compared to contemporary
silicone implants. A more permanent matrix equivalent to
polyurethane may be the
solution for reducing long-term capsular
contracture.
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