HISTOPATHOGICAL CHANGES OF ILEOCYSTOPLASTY:AN EXPERIMENTAL STUDY IN DOGS

To evaluate histopathogical changes in the urinary bladder after ileocystoplasty, an experimental model of five healthy mixed breed dogs weighing between 15-25kg, underwent partial cystectomy and immediate ileocystoplasty were used. One dog showed neobladder perforation and died ten days after operation. The remaining dogs did well, no digestive or voiding problems, no intestinal obstruction and urinary leakage were observed. Gross observations and histological sections were studied on day 45 after cystoplasty. Autopsy revealed distinct margin in the grafted area between bladder and the intestinal cap. No inflammatory exudative discharges, adhesion, leakage or fistulus formations were observed. The histological findings in neobladder showed original mucosa of the bowel persisted 45 days after cystoplasty in spite of its entirely new environment. Goblet cells hyperplasia were seen in the mucosa of the bowel. The other morphological findings were congestion, edema, inflammatory cell infiltration, metaplastic changes in the urothelium, cryptitis, calcification, heterotropic bone formation in graft area and the presence of fibroblasts, fibrocytes and collagen fibers in submucosa, muscular and serosal layers of the neobladder. Although the exact etiology of the histological changes is unclear, it seems that direct contact of the intestinal mucosa with urine is essential for the development of the morphologic changes and it has been showed that, in the absence of exposure to urine, morphological changes are not evident in the inner parts of ileal segments.