Congenital hydronephrosis in children can lead to kidney function issues, and identifying which cases require surgical intervention is essential. Previous studies have shown that renal medullary pyramidal thickness (PT) alone can predict the need for pyeloplasty, a surgical procedure to correct urinary obstruction, with moderate accuracy (AUC=0.78). Additionally, a novel pyeloplasty predictive score (PPS) using only objective ultrasound measurements achieved an AUC of 0.88. This study aimed to expand upon these findings by analyzing a larger group of children with hydronephrosis across grades 2, 3, and 4 to assess the effectiveness of sonographic measurements.
In a retrospective review of 166 children (188 hydronephrotic kidneys), 109 kidneys were observed, while 79 underwent pyeloplasty based on criteria including obstructive drainage patterns, declining renal function, or increased hydronephrosis. Key sonographic measurements—PT, anteroposterior diameter (APD), and renal length—were used to predict the need for surgery. Analysis showed that PT alone was highly predictive of pyeloplasty (AUC=0.821), with a PT threshold of less than 3 mm identifying 72% of kidneys needing surgery and correctly excluding 81% of those that did not. Multivariate models that included PT, APD, SFU grade, and other factors had predictive accuracies of AUC=0.901 (with SFU grade) and AUC=0.868 (without SFU grade), suggesting that objective measurements alone could be nearly as reliable as models that incorporate subjective grading systems.
The findings support PT as a valuable indicator for distinguishing hydronephrosis severity, with a PT under 3 mm serving as a reliable marker of thinned kidney parenchyma. A PPS using only PT, APD, and renal length may offer a more objective, consistent tool for managing hydronephrosis and deciding on surgical intervention, benefiting children by providing a standardized approach to assessing kidney health.
