Pillared-surface microstructure and soft-tissue implants: effect of implant site and fixation

Previous work with subcutaneous implants in a rat animal model has shown that pillarlike surface microstructure will reduce fibrosis and enhance blood vessel approximation to the implant surface when compared with nontextured controls. This study was designed to determine the effect of microtissue anatomy and implant site on the observed response, as well as the effect of implant fixation. The lateral posterior sites were found to contain a fat pad which produced a dramatically reduced fibrosis for the micro-structured implants compared with smooth controls. Although significant differences between pillar-micro-structured implants and controls were found for most sites, neither fascia nor muscle reduces the level of cellular response to the same degree as fat. Suture fixation of the implants did not produce a significantly different response in these tests. The occupation of the interpillar spaces by fat and moderation of interfacial shear forces is proposed as a mechanism to explain these results.