Facial augmentation with porous polyethylene (Medpor)--histological evidence of intense foreign body reaction.

Abstract

In a previous study by our group evaluating the clinical use of Medpor implants as augmentation material in the facial skeleton, we examined cases with unexpected intense foreign body reaction and focal disintegration of the implant material. The present study evaluates the histological findings in the largest series of explanted Medpor samples from human beings so far. Altogether 10 samples were harvested during revision surgery due to aesthetic contouring or due to infection. The average time from implantation to removal of the implants was 8.1 months. Paraffin embedding was employed for improved histological analysis. Chronic inflammation and foreign body giant cell reaction were seen in all cases. Intracytoplasmatic phagocytosis of disintegrated pieces of Medpor was seen as well as focal destruction of the material. From the histological point of view it is no longer justified to regard Medpor as an immunologically inert material. Nevertheless the reaction does not seem to be severe enough to compromise the stability and volume of the implant from a clinical point of view.