ULTRASOUND assessment showed progressive upper urinary tract (UUT) remodelling after successful pyeloplasty in children with ureteropelvic junction obstruction, with most reduction in renal pelvis diameter occurring during the first 6 months.
The prospective multicentre study included 31 paediatric patients who underwent pyeloplasty between 2021 and 2022. Standardised ultrasound assessments were performed at 2, 6 and 9 months and at 1 and 2 years after double J stent removal.
The primary outcome was the percentage reduction in anteroposterior diameter (APD) of the renal pelvis compared with baseline. Researchers also assessed cortical thickness and renal length on the operated and unaffected sides.
The median age at surgery was 6.5 months, with an interquartile range of 6.5–105.5 months. Before surgery, median renal pelvis APD was 24 mm (21–31 mm).
Ultrasound demonstrated a median APD reduction of 30% at 2 months and 60% at 6 months. Reductions continued more gradually thereafter, reaching 64.5% at 1 year and 71.4% at 2 years, with a range of 40.9–82.5% at 2 years.
These findings indicated that the most substantial reduction in renal pelvis dilation occurred during the early postoperative period, followed by more limited changes during subsequent follow-up.
Median cortical thickness on the operated side increased from 4.9 mm (3.3–5.5 mm) before surgery to 8 mm at 2 years, representing a 63% increase.
Renal length also increased during follow-up. At baseline, median renal length was 72 mm (55–123 mm) on the operated side and 60 mm (50–120 mm) on the unaffected side. At 2 years, these measurements had increased to 88 mm (62–138 mm) and 76 mm (60–120 mm), respectively.
The findings demonstrate that UUT remodelling after pyeloplasty was progressive and measurable using ultrasound. The early reduction in APD may help characterise expected postoperative changes, while continued cortical improvement over 2 years indicated a longer remodelling process. However, cortical thickness typically remained below normal values despite progressive improvement.
Lerendegui L et al. Ultrasound pattern of upper urinary tract remodeling after pyeloplasty: a prospective multicentric study. Pediatr Surg Int.2026;42:382.
Featured image: zinkevych on Adobe Stock
Each article is made available under the terms of the Creative Commons Attribution-Non Commercial 4.0 License.
