Development of the invaginated sleeve technique for continent cystostomies in dogs.

Two studies were undertaken in dogs to evaluate oblique tunnels through bladder walls lined by urothelium for use in continent cystostomies. In the first study, the tracts were lined completely by urothelium by 10 weeks, but tract calibre reduced considerably after stent removal and periluminal fibrosis was a prominent feature. In the second study a tubularised partial-thickness pedicle graft was invaginated through an oblique tunnel in the bladder wall, with the graft extending extravesically and then being wrapped in omentum. This technique provided complete urothelial covering by 2 weeks with much less periluminal fibrosis. In the 3 dogs catheterised daily up to 120 days, this technique afforded continence with generous tracts for catheterisation.