FLEXIBLE TANTALUM STENTS - EFFECTS IN THE STENOTIC CANINE URETHRA

Purpose: Evaluate the effects of flexible tantalum stents (Strecker) i mplanted into stenotic canine urethras. Methods: Eight conditioned, ad ult, German shepherd dogs, weighing 30-40 kg, were used. Strictures we re created surgically in the bulbar urethra just proximal to the os pe nis. Two months postsurgery, strictures were documented radiographical ly and then balloon dilated. Following dilatation, a single Strecker s tent was placed across the stricture. Stents were 7 mm in expanded dia meter and either 2 or 4 cm in length. Retrograde urethrography was per formed immediately after stent placement and then biweekly for up to 1 2 months. Two dogs were sacrificed at 2, 4, 6, and 12 months poststent ing, and necropsy was performed. The urethra was excised, fixed, and e xamined by scanning electron and light microscopy. Results: Clinical s uccess was achieved without complications in all animals. Hyperplasia of the urothelium was noted 4-6 weeks after stent placement and was mo st pronounced at 4-6 months. Mucosal folds were found between the sten t struts. Restenosis occurred at the distal end of the stent in one do g. Histological alterations were noted in the deeper layers of the ure thral wall. Conclusion: Strecker stents were well tolerated in all ani mals and seem useful for the treatment of urethral strictures.