Does renal function remain stable after puberty in children with prenatal hydronephrosis and improved renal function after pyeloplasty?

ABSTRACT

PURPOSE: We evaluated whether improved renal function after pyeloplasty for prenatal ureteropelvic junction obstruction persisted through puberty. MATERIALS AND METHODS: A total of 441 males and 137 females with a prenatal diagnosis of hydronephrosis that led to the postnatal diagnosis of ureteropelvic junction obstruction were followed at our department from 1989 to 2008. Of the patients we reviewed the records of 49 who underwent surgery between 1989 and 1992, and completed puberty. Hydronephrosis was on the right side in 18 children (36.7%) and on the left side in 31 (63.3%). According to Society for Fetal Urology classification at first presentation postnatal hydronephrosis was grades 2 to 4 in 18 (36.7%), 23 (46.9%) and 8 children (16.3%), respectively. Initially relative renal function was more than 40% in 18 children (36.7%), between 30% and 40% in 24 (49%), and less than 30% in 7 (14.3%). Preoperatively mean +/- SEM relative renal function was 36.6% +/- 7.8% in all reviewed patients. RESULTS: Improvement in hydronephrosis was confirmed in all patients. This remained stable during and after puberty in all except 2 patients, who required endopyelotomy 8 and 10 years following pyeloplasty, respectively, due to deterioration in hydronephrosis without a decrease in relative renal function. They showed improvement in the washout curve pattern after the procedure. Pyeloplasty led to increased relative renal function in the short term from 36.7% +/- 1.2% before surgery to 41.2% +/- 0.91% in all patients (p <0.001). It remained stable at 43.2% +/- 0.75% after puberty in all reviewed patients. CONCLUSIONS: To our knowledge our data show for the first time that successful pyeloplasty after the prenatal diagnosis of ureteropelvic junction obstruction is associated with improved renal function throughout puberty.