Factors Indicating Renal Injury in Pediatric Bilateral Ureteropelvic-junction Obstruction

Objective To analyze the factors indicating renal injury in patients with bilateral ureteropelvic-junction obstruction (UPJO). Methods We investigated 26 patients, 35 kidney units (KUs), who were diagnosed with bilateral UPJO and underwent unilateral or bilateral pyeloplasty between January 2000 and December 2011. During pyeloplasty, ipsilateral kidney biopsy was performed. Kidney biopsy results were divided into 3 categories. Hydronephrosis was analyzed using both the Society of Fetal Urology (SFU) and Onen's grading system. We investigated factors related with the renal histopathologic results of 29 KUs. We additionally analyzed whether there were factors predicting contralateral pyeloplasty after initial unilateral pyeloplasty. Results Ten KUs (34.5%) showed grade 1 histopathologic change, whereas 10 KUs (34.5%) and 9 KUs (31.0%) showed grade 2 and 3 change, respectively. Preoperative differential renal function (DRF) and serum creatinine levels were not different among groups ( P = .697 and .516, respectively). Hydronephrosis grade was not different when graded by SFU system ( P = .100) while significantly different by Onen's system ( P