Enteric mucosal regrowth after bladder augmentation using demucosalized gut segments

Purpose: Regrowth of the enteric mucosa on a denuded muscular flap enterocystoplasty is an undesirable complication of demucosalized enterocystoplasty. This study was performed to understand how regrowth can be prevented and, thus, a complete urothelial lined enterocystoplasty can be achieved. Materials and Methods: We performed bladder augmentation on 30 sheep using demucosalized seromuscular gastric or colonic flaps with or without autoaugmentation. The epithelium and muscularis mucosae were completely removed from the gastric flap. Initial attempts to remove the muscularis mucosae and most of the submucosal layer from the colonic flap by cautery caused bleeding and muscle damage. Thus, demucosalization was done by stripping with forceps, in which the muscularis mucosae and submucosa remained largely intact on the colonic flap. Sheep were sacrificed 4 to 12 months postoperatively and bladders were inspected for mucosal regrowth. Subsequently autoaugmentation with demucosalized seromuscular gastric or colonic flaps was performed clinically in 10 children in whom the enteric epithelium and muscularis mucosae were removed completely with part of the submucosa by dissection through the submucosal plane. These children were followed with urodynamic studies and mucin staining of urine up to 39 months postoperatively. Results: Regrowth of islands of enteric mucosa occurred in 4 of the 5 animals in which the muscularis mucosae and submucosal layers were preserved on a colonic flap. In all animals with mucosal regrowth the bowel was prepared by stripping the mucosa. Mucosal regrowth did not occur in any animal after complete removal of the muscularis mucosae and the inner portion of the submucosa from the stomach or colon. All patients had satisfactory urodynamic results and no evidence of enteric mucosal regrowth. Conclusions: Removal of the muscularis mucosae with the inner portion of the submucosa appears necessary to prevent enteric mucosal regrowth on the muscular flap of a demucosalized enterocystoplasty. In addition, this level of dissection does not seem to interfere with the success of bladder augmentation in children.