SURGERY VERSUS OBSERVATION FOR MANAGING OBSTRUCTIVE GRADE 3 TO 4 UNILATERAL HYDRONEPHROSIS: A REPORT FROM THE SOCIETY FOR FETAL UROLOGY

AbstractPurpose: The Society for Fetal Urology has undertaken the first multicenter prospective randomized study of high grade obstructive unilateral hydronephrosis to evaluate the natural history of untreated obstruction and compare it to the benefits of pyeloplasty.Materials and Methods: Since 1991, infants with isolated unilateral Society for Fetal Urology grade 3 hydronephrosis and ipsilateral obstruction with greater than 40% differential renal function on well tempered renography were studied. Patients were randomly assigned to observation or pyeloplasty groups. Renal ultrasound and well tempered renography were performed biannually for 1 year and yearly thereafter. Crossover criteria for surgery included concurrent worsening of isotope washout and increasing grade of hydronephrosis or a greater than 10% point loss in percent differential renal function that was noted between studies. The end point of the study was the 3-year anniversary of randomization.Results: A total of 32 infants from 10 center...