Effect of microtextured surfaces on the performance of percutaneous devices

Along the percutaneous part of implantable devices, like (semi-)permanent catheters, epithelial downgrowth can occur. This process can eventually lead to implant loss. Various treatments for the catheter surface have been proposed, to improve their performance. The purpose of the current study was to investigate the effect of a microgroove pattern on the tube surface, on epithelial downgrowth. Catheterlike implants were made of silicone tubes, with anchoring cuffs made of titanium-fiber mesh. A thin sheet of silicone with microgrooves was applied on the tubes. Two types of texturing were used, a square groove of 10 microm wide and 1 microm deep; or a V-shaped groove of 40 microm wide. The grooves were directed either along the long axis of the catheter tube (grooves perpendicular to the skin surface) or circling around the catheter (grooves directed parallel to the skin surface). As controls, catheters with a smooth outer surface were used. Implants were placed in 30 rats, with a follow-up period of 9 weeks. During this time, animals were inspected biweekly, and catheter exit sites were evaluated using a scoring system. At the end of the 9-week period the implants and surrounding tissues were processed for histological evaluation. For the clinical evaluation of the exit sites, no statistical differences were found between the study groups. Histologically, epithelial downgrowth was observed for all samples. The histomorphometrical measurements showed that there were no differences in downgrowth between the smooth and parallel-grooved catheters. However, there was increased epithelial downgrowth along the catheters with grooves perpendicular to the skin. In conclusion, a grooved microtexture can direct epithelial tissue ingrowth, but this study found no beneficial effects of the guidance phenomenon.