Flexible tantalum stents: effects in the stenotic canine urethra.

Abstract

Evaluate the effects of flexible tantalum stents (Strecker) implanted into stenotic canine urethras. Eight conditioned, adult, German shepherd dogs, weighing 30-40 kg, were used. Strictures were created surgically in the bulbar urethra just proximal to the os penis. Two months postsurgery, strictures were documented radiographically and then balloon dilated. Following dilatation, a single Strecker stent was placed across the stricture. Stents were 7 mm in expanded diameter and either 2 or 4 cm in length. Retrograde urethrography was performed immediately after stent placement and then biweekly for up to 12 months. Two dogs were sacrificed at 2, 4, 6, and 12 months post-stenting, and necropsy was performed. The urethra was excised, fixed, and examined by scanning electron and light microscopy. Clinical success was achieved without complications in all animals. Hyperplasia of the urothelium was noted 4-6 weeks after stent placement and was most pronounced at 4-6 months. Mucosal folds were found between the stent struts. Restenosis occurred at the distal end of the stent in one dog. Histological alterations were noted in the deeper layers of the urethral wall. Strecker stents were well tolerated in all animals and seem useful for the treatment of urethral strictures.