Does every patient with ureteropelvic junction obstruction need voiding cystourethrography?

Purpose: Voiding cystourethrography is routinely recommended to detect vesi coureteral reflux in children with ureteropelvic junction obstruction. Vesi couretral reflux coexisting with primary ureteropelvic junction obstruction is usually of low grade and resolves spontaneously after pyeloplasty, wher eas pseudo ureteropelvic junction obstruction and obstruction secondary to high grade reflux usually present with a dilated ureter that is easily dete cted on real-time ultrasonography. We assessed the role of voiding cystoure thrography in children with ureteropelvic junction obstruction by retrospec tively evaluating the incidence and natural history of coexisting vesicoure thral reflux. Materials and Methods: We reviewed the records of 106 children younger than 15 years who underwent pyeloplasty for ureteropelvic junction obstruction at our hospital between January 1990 and December 1998. A patient who had i nitially undergone antireflux surgery later underwent pyeloplasty for newly developed secondary obstruction was not included in the analysis. The diag nosis of ureteropelvic junction obstruction was based on ultrasonography an d diuretic renography. Preoperative voiding cystourethrography was performe d in all patients to detect vesicourethral reflux. We categorized reflux as low grade if the ureters were not dilated and as high grade if the ureters were dilated and tortuous. Results: There were 89 boys and 17 girls who underwent 115 pyeloplasties, i ncluding 9 who underwent bilateral pyeloplasty. Mean patient age at surgery was 27.4 months (63 infants, 6 between 1 and 2 years old, and 37 older tha n 2 years). Of these 106 patients 85 had unilateral (left side 64, right si de 21) and 21 had bilateral ureteropelvic junction obstruction. Vesicoureth ral reflux was documented in 19 ureters of 12 children. Of the 85 cases of unilateral ureteropelvic junction obstructions 10 had vesicourethral reflux , which was bilateral 6, ipsilateral in 2 and contralateral in 2. Of the 21 cases of bilateral obstructions 2 had reflux, which was bilateral in 1 and was unilateral in 1. Reflux was low grade reflux in 6 and high grade in 6 cases. All low grade reflux disappeared spontaneously at an average period of 4.2 months (range 2 to 10) after pyeloplasty. All 6 patients with high g rade reflux subsequently underwent antireflux surgery because of breakthrou gh urinary tract infection in 2 and persistent in 4 at an average of 36 mon ths (range 3 to 112) after pyeloplasty. All high grade reflux coexisting wi th ureteropelvic junction obstruction was easily detected on real-time ultr asonography. Conclusions: Low grade reflux coexisting with ureteropelvic junction obstru ction spontaneously disappeared after pyeloplasty, and all high grade reflu x coexisting with obstruction was easily detected on ultrasonography using real-time mode. Therefore, we believe that indication for voiding cystouret hrography in children with ureteropelvic junction obstruction should be lim ited to those with dilated ureters on ultrasonography.