THE USE OF THE AMS800 ARTIFICIAL URINARY SPHINCTER IN COMBINATION WITH THE GASTRIC TUBE FOR CONTINENCE IN THE CANINE MODEL

An experimental canine model was designed to examine the potential use of the artificial urinary sphincter around a gastric tube. The artifi cial urinary sphincter was placed around a tubularized gastric flap as part of a continent gastric reservoir in 4 dogs and in 2 additional d ogs the gastric tube was anastomosed to the native bladder. Two dogs u nderwent placement of the artificial urinary sphincter around the gast ric tube 4 weeks postoperatively and the remainder had the sphincter p laced simultaneously with creation of the gastric tube. All dogs with the gastric reservoir underwent urodynamics before and after activatio n of the sphincter. Only 61 to 70 cm. water pressure balloons were use d. All dogs were continent postoperatively on clean intermittent cathe terization every 8 hours. There were no erosions or problems with cath eterization. Urodynamics confirmed a compliant system and an average i ncrease of capacity of 410% after artificial urinary sphincter activat ion (4 dogs). There was no leakage at capacity. Histology of the artif icial urinary sphincter and neighboring (control) regions, and of the reservoir at 1 (2 dogs), 3 (3 dogs) and 6 months (1 dog) was obtained. Microscopic examination of the cuff site showed mild serosal hyperpla sia and fibrosis, a well preserved muscularis and mild to moderate foc al mucosal atrophy. These changes were slightly more evident at 6 mont hs. Mucosal folds were well preserved with normal submucosa and lamina propria. ln the control region histology was well preserved and simil ar to native stomach. We conclude that the artificial urinary sphincte r around a gastric tube can provide urinary continence. The minimal ch anges in histology under the cuff are encouraging and support the pote ntial for use of the gastric tube with the artificial urinary sphincte r, although longer term effects are unknown.