RESUMEN
Unilateral ureterosigmoidostomy (U.S.S.) was performed on 15 rabbits and then the animals were sacrificed after 3, 8 and 15 months. The gross appearance of the kidney and radiological investigations revealed enlargement of the pelvis and of the ureter on the operated side although the anastomosis was patent in all cases. In rabbits sacrificed 8 months after U.S.S. an adenomatous polyp was present at the site of anastomosis. Histological examination of the affected kidney showed pyelonephritis secondary to obstruction and immunopathological studies revealed in some rabbits glomerular and tubular deposition of immunoglobulins and complement. The contralateral kidney was always normal. Biochemical investigations showed only a moderate increase in blood urea nitrogen and plasma creatinine values.