The gastric bladder: a continent reservoir for urinary diversion.

A continent reservoir ("gastric bladder") has been developed as an alternative to ileal conduits after urinary diversion procedures. The reservoir is fashioned from vagally denervated gastric fundus and has antireflux ureterogastric anastomoses and a continent "neourethra," the latter which is easily catheterized to empty the contents; the main stomach retains vagal innervation. Continent reservoirs were prepared in six dogs, and Heidenhain pouches (without urinary diversion) were prepared in six control dogs. Effects of short-term and long-term exposure of gastric mucosa to urine and 1M, 2M and 4M urea solutions were studied. Basal and food-stimulated acid outputs were unaffected by prolonged exposure. Mucosal permeability to H+, Na+, K+ and Cl- after exposure to urine remained unaltered, but 4M urea solutions produced a temporary increase in permeability. Mucosal blood flow was unchanged. Reservoir capacity rapidly increased up to 2,000 ml without any change in serum electrolytes. No precipitation of uric acid occurred. No histologic differences were noted between the main stomach and the reservoir. Because gastric mucosa (especially when acidified) is relatively impermeable to ions, secretes rather than absorbs Cl-, and is unaffected by prolonged exposure to urine, a gastric pouch may be useful as a continent urinary reservoir while allowing the maintenance of normal serum electrolytes.