Is voiding cystourethrography necessary for evaluating unilateral ectopic pelvic kidney?

The aim of this study is to evaluate if voiding cystourethrography (VCUG) is necessary for the evaluation of unilateral ectopic pelvic kidney (UEPK) in order to identify vesicoureteral reflux (VUR).

Files of the patients who had been followed-up for ectopic pelvic kidney in two pediatric nephrology clinics between August 2011 and December 2017 were retrospectively reviewed. Other anomalies, such as crossed, fused, and bilateral pelvic ectopia were excluded. Preliminary diagnoses were made via urinary ultrasonography while dimercaptosuccinic acid scintigraphy was carried out to confirm the diagnoses. Differential renal function and presence of renal scars was checked. VCUG results were obtained and those patients that showed VUR were noted.

A total of 72 patients were included in the study (41 males and 31 females). The median patient age was 4.1 years (range: 2 months-14.5 years). Hydronephrosis was present in only 4 patients (5.6%), where 1 one of those was on the contralateral side. UEPKs contributed to the mean 37.9±7.8% of total renal function and 15% of these patients had renal scars (expressed as a global reduction in function, not as patchy scars). VCUG was obtained in 42 patients and VUR was present in only 1 patient (2.4%). The median follow-up period was 16.5 months (range: 3-92 months).

The results of our study indicated that hydronephrosis and VUR are not common in UEPKs. Therefore, routine VCUG should be avoided in the evaluation of UEPK in order to protect patients from unnecessary radiation exposure and an increased risk of urinary tract infections.