Seromuscular colocystoplasty lined with urothelium: experimental study.

OBJECTIVES

Enterocystoplasty without bowel mucosa would be useful to prevent most complications related to the presence of bowel in the urinary tract. However, past attempts to remove the mucosa from intestinal segments have resulted in fibrosis and contraction of the patch. We designed this study to test the hypothesis that such contraction can be prevented by combining the principle of detrusorectomy and seromuscular colocystoplasty, covering the denuded urothelium with a de-epithelialized colonic segment, a procedure we named seromuscular colocystoplasty lined with urothelium (SCLU).

METHODS

SCLU was performed in 14 female mongrel dogs weighing 20 to 25 kg. We performed the procedure with and without preservation of the intestinal submucosa and in animals with intact and previously reduced bladders. We describe a new animal model of reduced bladder capacity. Bladder capacity and histology were evaluated 1 to 6 months after the procedure.

RESULTS

Twelve bladder specimens were available for analysis. In all cases, the seromuscular patches remained viable and well vascularized. When the intestinal submucosa was not preserved in the patch, there was moderate contraction of the patch with subepithelial fibrosis and the bladder capacity was not preserved. In contrast, when the submucosa was preserved, there was no fibrosis and the capacity was preserved. In animals with previously reduced bladder capacity by either subtotal cystectomy or talc-induced fibrosis, SCLU effectively augmented bladder capacity.

CONCLUSIONS

The results suggest that the contraction of the intestinal patch in seromuscular enterocystoplasty can be avoided by the preservation of both the bladder urothelium and lamina propria, together with the submucosa and muscularis mucosa of the intestinal patch.