Urothelial ingrowth over demucosalized gastrocystoplasty: an experimental study

To evaluate histopathologically the ingrowth of urothelium over a demucosalized gastric flap used for augmentation, as such flaps increase the capacity of the bladder if the urothelium can cover the seromuscular patch.

The study included eight male dogs; the urinary bladder was widely divided at its dome anteroposteriorly to receive a seromuscular gastric flap, sutured to the edges of the urinary bladder. Before and 1 month after surgery the changes in bladder capacity and pressure were recorded, and urothelial ingrowth assessed histopathologically.

Two of the eight dogs died; the increase in mean bladder capacity in the remaining dogs was 20% and the decrease in mean intravesical pressure 34%. Gross pathological examination of the urinary bladder showed good 'take' of the gastric flap by the urinary bladder. Histopathologically, there was good healing of the flap, active ingrowth of urothelium, and no mucosal re-growth.

Bladder augmentation with a demucosalized gastrocystoplasty allows the creation of a large compliant urinary bladder with few complications caused by the incorporation of the enteric or gastric epithelium into the urinary bladder. The stomach has a rich blood supply, allowing the harvesting of a well-vascularized flap, and urothelial ingrowth over this flap in the present study was significant.