External catheter immobilization improves wound healing in micropigs

Recurrent traumatic damage by mechanical action is a major cause of catheter exit site problems in CAPD patients. The purpose of this study was to determine the efficacy of a new external immobilization device (Immobilizer) on wound healing characteristics at the catheter exit site. Sixteen Tenckhoff catheters were surgically implanted in four Yucatan micropigs (two catheters per flank). Immobilization devices were placed on one catheter on each side of each animal; the other catheter was allowed free movement. The devices were changed daily, and exit sites were examined for wound healing progress and infection. Fourteen days following implantation the animals were sacrificed, and the catheter exit sites explanted for histologic examination. The results of this study suggest that immobilization of catheters with this device improves wound healing at the exit site, as evidenced by decreased (p less than 0.05) marsupialization/epidermal down-growth (nonimmobilized 2.9 mm vs. immobilized 1.6 mm), and an increased (p less than 0.05) macrophage/epithelioid cell/giant cell response within the exit tract or in the Dacron cuff (granulomatous response histology score of 2.3 for immobilized vs. a histology score of 1.6 for nonimmobilized). Thus, use of this device may help reduce catheter exit site problems in CAPD patients.