Predictive value of renal histopathological changes for renal functional improvement after pyeloplasty in patients with pelviureteric junction obstruction

Abstract

Anderson-Hynes dismembered pyeloplasty remains the gold standard surgical treatment for pelviureteric junction obstruction (PUJO). However, the extent of renal functional recovery following pyeloplasty continues to be debated. Numerous clinical and sradiological parameters have been proposed to predict postoperative renal function improvesment, yet with inconsistent outcomes. This study aimed to evaluate the degree of histopathological alterations in obstructed renal parenchyma and determine their predictive value for functional recovery after pyeloplasty. In this prospective observational study, renal biopsies were obtained intraoperatively during pyeloplasty from sixteen pediatric and adult patients diagnosed with PUJO. Histopathological changes were graded from I to III based on severity. Differential renal function (DRF), assessed by diethylene triamine pentaacetic acid (DTPA) renal scintigraphy was recorded preoperatively and at 6 months postoperatively. Associations between histological grade and functional outcomes were analyzed using Fisher’s exact test for categorical variables and Wilcoxon signed-rank test for continuous variables. A significant correlation was observed between the severity of histopathological damage and postoperative renal functional recovery. Thirteen patients (81.3%) with mild to moderate changes (Grade I-II) demonstrated significant improvement in DRF at 6 months following pyeloplasty (P0.05). Overall, postoperative DRF improved in 13 patients, while 3 patients experienced a decline. No significant association was found between preoperative DRF and histopathological grade. The severity of PUJO-related histopathological alterations in renal parenchyma serves as a valuable predictor of renal functional recovery after pyeloplasty. Patients with mild to moderate renal biopsy changes are more likely to achieve meaningful postoperative improvement, whereas severe histological damage may indicate limited functional reversibility.