ENTERIC MUCOSAL REGROWTH AFTER BLADDER AUGMENTATION USING DEMUCOSALIZED GUT SEGMENTS

Purpose: Regrowth of the enteric mucosa on a denuded muscular flap ent erocystoplasty is an undesirable complication of demucosalized enteroc ystoplasty. This study was performed to understand how regrowth can be prevented and, thus, a complete urothelial lined enterocystoplasty ca n be achieved. Materials and Methods: We performed bladder augmentatio n on 30 sheep using demucosalized seromuscular gastric or colonic flap s with or without autoaugmentation. The epithelium and muscularis muco sae were completely removed from the gastric flap. Initial attempts to remove the muscularis mucosae and most of the submucosal layer from t he colonic flap by cautery caused bleeding and muscle damage. Thus, de mucosalization was done by stripping with forceps, in which the muscul aris mucosae and submucosa remained largely intact on the colonic flap . Sheep were sacrificed 4 to 12 months postoperatively and bladders we re inspected for mucosal regrowth. Subsequently autoaugmentation with demucosalized seromuscular gastric or colonic flaps was performed clin ically in 10 children in whom the enteric epithelium and muscularis mu cosae were removed completely with part of the submucosa by dissection through the submucosal plane. These children were followed with urody namic studies and mucin staining of urine up to 39 months postoperativ ely. Results: Regrowth of islands of enteric mucosa occurred in 4 of t he 5 animals in which the muscularis mucosae and submucosal layers wer e preserved on a colonic flap. In all animals with mucosal regrowth th e 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 enteri c mucosal regrowth. Conclusions: Removal of the muscularis mucosae wit h the inner portion of the submucosa appears necessary to prevent ente ric mucosal regrowth on the muscular flap of a demucosalized enterocys toplasty. In addition, this level of dissection does not seem to inter fere with the success of bladder augmentation in children.