URETERAL RESPONSE TO THE PLACEMENT OF METALLIC STENTS - AN ANIMAL-MODEL

Metallic self-expanding mesh stents are increasingly used in the urina ry tract. Little is known about the histological reactions that such p rostheses have on the surrounding tissue. The effects of self-expanded metallic stents in the histologically normal ureter were examined in four dogs. Three-mm. Gianturco-Roubin coronary artery stents were intr oduced into the distal left ureter after dilatation. Follow-up excreto ry urography, retrograde pyelograms and autopsy were performed on 2 do gs at 1 month and on 2 dogs at 6 months. In all 4 dogs, the ureters re mained patent. Histologic examination of the ureter showed that the st ents had not become incorporated within the wall of the ureter. Reacti ve changes seen in the epithelium included penetration of both epithel ium and submucosa between the wire struts and areas of fibrosis in the submucosal layer. The use of metallic stents in histologically normal ureters may be limited in the long term by this inflammatory response .