Enterocystoplasty and reflux nephropathy in the canine model

Correction of vesicoureteral reflux at enterocystoplasty is often recommended to prevent the development of reflux nephropathy. Children with enterocystoplasty who require intermittent self-catheterization invariably have asymptomatic bacteriuria. In patients with persistent vesicoureteral reflux after enterocystoplasty the risk of renal damage from this asymptomatic bacteriuria is unknown. Detubularized ileocystoplasty was performed in 17 dogs with either direct nontunneled reimplantation or unroofing of the intramural tunnel and incision of the ipsilateral hemitrigone to create vesicoureteral reflux. Fluoroscopic urodynamic studies were performed 1 month later and unilateral vesicoureteral reflux was present in 6 dogs. All animals had low intravesical pressure and excretory urograms were performed to exclude obstruction. The 6 dogs with reflux were euthanized 3 months postoperatively and the kidneys were examined for histological evidence of pyelonephritis. In 5 of 6 dogs bacterial bladder colonization and subsequent renal pelvic colonization developed on the side of the vesicoureteral reflux. All of these animals had histological evidence of pyelonephritis in the refluxing kidney, whereas only 1 of 6 nonrefluxing control kidneys had any evidence of pyelonephritis (p = 0.031). Our results suggest that vesicoureteral reflux in association with enterocystoplasty leads to chronic upper tract infection and pyelonephritis in a majority of animals, despite creation of a low pressure urinary reservoir. Correction of vesicoureteral reflux at enterocystoplasty should be considered to prevent upper tract damage.