Incidence of vesicoureteral reflux in children with unilateral renal agenesis.

We retrospectively reviewed 51 pediatric cases of unilateral renal agenesis to determine the incidence of contralateral vesicoureteral reflux. Initial diagnosis of unilateral renal agenesis was made by evaluation of associated congenital abnormality in 21 patients, evaluation of prenatally detected abnormality in 11, evaluation of urinary tract infection in 7, sibling screening in 3, hypertension in 2 and other methods in 7. A voiding cystourethrogram was obtained in 44 cases. Indications for the study included urinary tract infection in 11 patients, hydronephrosis in 18 and screening in 15. Overall, vesicoureteral reflux occurred in 19 of the 51 patients (37%). The highest incidence of contralateral reflux was in those with a prenatal abnormality with or without hydronephrosis (77%) although 5 of 15 patients (33%) who underwent a screening voiding cystourethrogram had reflux. Mean followup was 50 months. Of the patients with vesicoureteral reflux reimplantation was performed in 9, reflux spontaneously resolved in 3 and reflux persisted in 7. There is a high incidence of vesicoureteral reflux in children with unilateral renal agenesis and a voiding cystourethrogram is recommended even in the absence of hydronephrosis or urinary tract infection. Although 50% of children in our series underwent surgical intervention, a period of nonoperative observation is warranted.