Prenatal sonographic predictors of postnatal pyeloplasty in fetuses with isolated hydronephrosis

Hadar Mudrik-Zohar*, Israel Meizner, Zvi Bar-Sever, David Ben-Meir, Miriam Davidovits

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Objective: To define prenatal sonographic predictors of ureteropelvic junction obstruction requiring postnatal pyeloplasty, in fetuses with isolated hydronephrosis. Methods: Retrospective data on prenatal sonographic parameters were compared between patients who had been diagnosed prenatally with hydronephrosis and either underwent postnatal pyeloplasty for ureteropelvic junction obstruction (n=39) or were treated conservatively (n=30). Results: Significant differences between the surgically and conservatively treated patients were found for mean anterior-posterior renal diameter (22.8±8.6 vs 14.2±5.9mm, respectively, p<0.0001) and parenchymal thickness (5.9±2.8 vs 8.1±2.6mm, p=0.009). Anterior-posterior diameter >14mm was the best single predictor of the need for surgery (area under the ROC curve, 0.817), with sensitivity 77%, specificity 69%, positive predictive value (PPV) 77% and negative predictive value (NPV) 69% (β=1.17, 95%CI=1.07-1.28, p<0.001). Mean ratio of anterior-posterior diameter to parenchymal thickness was significantly higher in the postnatal pyeloplasty group (5.4±4.5 vs 2.1±1.4, p=0.0001). A ratio >2.1 had a sensitivity of 87% and specificity of 65% for the need for surgery (area under the curve 0.822, PPV 79%, NPV 77%; β=1.92, 95%CI=1.16-3.17, p<0.001). Conclusion: In cases of prenatal isolated hydronephrosis, the pelvic anterior-posterior diameter and parenchymal thickness may predict the need for postnatal pyeloplasty. A ratio of >2.1 of pelvic anterior-posterior diameter to parenchymal thickness suggests ureteropelvic junction obstruction and supports the use of more intensive prenatal and postnatal surveillance.

Original languageEnglish
Pages (from-to)142-147
Number of pages6
JournalPrenatal Diagnosis
Issue number2
StatePublished - 1 Feb 2015


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