Chronic transcutaneous access is needed for peritoneal dialysis (PD) and new emerging medical therapies. Since a transcutaneous device breeches the skin, the normal barrier to bacterial entry, infection is a significant problem over long periods. The objective of this program is the design and testing of an all-titanium transcutaneous access device (TAD) that will be significantly more resistant to exit site infection than existing PD catheters. The device employs microporous titanium metal (MTM) to obtain a stable epithelial junction at the exit site, inhibit bacterial entry, and facilitate improved exit site hygiene. MTM is a new material for soft tissue applications. The porous metal surface provides a complicated three-dimensional matrix whose internal geometry is fully adjustable. Connective tissue proliferation into the porous metal creates a physical barrier to prevent bacterial entry, and it also limits epithelial down-growth that can lead to sinus tract formation. In preliminary studies, it has been shown that this material provokes a minimal foreign body response with virtually no inflammation in comparison to polymer fiber surfaces used on conventional PD catheters. Foreign body giant cells are not found adjacent to the material, which is encapsulated in a thin, collagenous tissue capsule whose attachment to the material exceeds the tensile strength of the tissue. These are characteristics that make the material uniquely suitable for this application. In Phase I, we will design, build, and test the all-titanium TAD and evaluate it using an adult sheep animal model in studies of 8 week duration using Tenckhoff PD catheters as a control. We will characterize healing at the exit site, and a bacterial challenge test will be employed to compare the ability of the new device to prevent bacterial entry versus a conventional PD catheter. Chronic transcutaneous access is needed for peritoneal dialysis and new emerging medical therapies. As a transcutaneous device breeches the skin, the normal barrier to bacterial entry, exit site infection is a significant problem over long periods. The objective of this program is the design and testing of an all- titanium transcutaneous access device (TAD) designed to be resistant to infection and provide a stable skin interface. ? ? ?
