No clear predictors for time to hydronephrosis resolution after pyeloplasty in kids

Despite high rates, the resolution of hydronephrosis in children after pyeloplasty remains poorly understood, reports a recent study. Neither the type of surgical approach nor of obstruction seems to impact the rate of hydronephrosis resolution in this population.

“There is neither any difference in the natural course of hydronephrosis between different types of surgical approach, nor any difference between the various types of obstructions,” the researchers said. “Thus, the same follow-up plan applies after paediatric pyeloplasty regardless of type of surgical approach or type of obstruction.”

Researchers retrospectively assessed 125 children (aged <15 years; 59 percent boys) who had been treated with pyeloplasty. Outcomes included 2-year success rate and the time to resolution of hydronephrosis, which was defined as an anterior-posterior diameter (APD) <10 mm or a >50-percent reduction in APD.

Children saw a decrease in median APD during the postoperative follow-up, dropping from 30 mm before the procedure to 10 mm by 6 months and <10 mm by 24 months.

Hydronephrosis was resolved within 12 months in 90 percent of the participants (n=113); all the remaining 12 patients had stable or improved renal function. Beyond 24 months, only nine patients (7 percent) had still unresolved hydronephrosis.

Multivariable Cox regression analysis could not identify significant factors associated with the resolution of hydronephrosis. Surgical approach, for instance, had no evident impact. Neither open surgery (adjusted hazard ratio [aHR], 0.90, 95 percent confidence interval [CI], 0.54–1.52; p=0.70) nor flank incision (aHR, 0.75, 95 percent CI, 0.42–1.31; p=0.31) yielded better resolution rates relative to robotic-assisted laparoscopic pyeloplasty.

Moreover, children with larger APD were also not significantly slower to achieve resolution than their counterparts with less dilatation (p=0.79). Comparing the two different definitions of resolution likewise revealed no significant difference in the time to resolution (p=0.09).