Renal ultrasound changes after internal double-J stented pyeloplasty for ureteropelvic junction obstruction

Purpose: Renal ultrasound changes after pediatric pyeloplasty were reported recently in the literature, mainly on unstented pyeloplasties. We evaluated the time to improvement or resolution of hydronephrosis in pediatric patients who underwent double-J stented pyeloplasty for ureteropelvic junction (UPJ) obstruction and compared our results to unstented pyeloplasties. Materials and Methods: Ultrasonic grading of hydronephrosis after double-J stented pyeloplasty was performed according to the Society for Fetal Urology criteria at intervals of 0 to 3, 3 to 6, 6 to 12, and greater than 12 months postoperatively. Twenty-six pyeloplasties met all criteria for inclusion. The median patient age was 4 months. Results: Of the 26 pyeloplasties studied, 18 kidneys had grade 4, 7 grade 3, and 1 grade 2 hydronephrosis. Twenty-two percent of kidneys with grade 4 hydronephrosis had resolution of pyelocaliectasis at the 0- to 3-month ultrasound examination; all of these kidneys had the stents removed prior to being studied. No patient with improvement of hydronephrosis worsened on subsequent examinations. All but three patients improved over 1-year follow-up: 11 (42%) to grade 0, 5 (19.2%) to grade 1, 6 (23%) to grade 2, and 1 (3.8%) to grade 3. The average final grade was 1.56 for grade 4 and 0.57 for grade 3 hydronephrosis. This represented more rapid improvement than unstented pyeloplasties. Average indwelling time for double-J stent was 52 days. Conclusions: Improvement and sometimes resolution of hydronephrosis after internal double-J stented pyeloplasty for UPJ obstruction is rapid and can occur within the first 3 months postoperatively. One year postoperatively, the majority of renal units have grade 2 hydronephrosis or less. We recommend the use of indwelling double-J ureteral stents in all pediatric patients undergoing dismembered pyeloplasty for UPJ obstruction to allow for more rapid improvement and possible resolution of pyelocaliectasis. Further comparison of stented vs. unstented pyeloplasty is needed.