Abstract
OBJECTIVES: While early outcomes after pyeloplasty are well-documented, long-term split renal function (SRF) stability, particularly beyond puberty, remains unclear. This study evaluates SRF after prepubertal pyeloplasty and identifies factors associated with late deterioration. METHODS: A retrospective review included paediatric patients who underwent pyeloplasty between 2000 and 2025. Exclusion criteria were solitary kidney, missing imaging, congenital anomalies or prior pyeloplasty. Patients were categorised into two groups: Group 1 (no deterioration) and Group 2 (late deterioration after puberty), based on ≥5% decrease in SRF. Clinical, surgical and imaging parameters were compared among groups using Chi-square, Fisher's exact and Mann-Whitney U tests, with multivariate logistic regression to identify predictors of late deterioration. RESULTS: Out of 1493 patients, 191 were included: 152 (79.6%) in Group 1 and 39 (20.4%) in Group 2. Group 2 patients were younger at surgery, had more frequent renal pelvis reduction and persistent hydronephrosis at 1-year follow-up (p < 0.001). Multivariate analysis identified renal pelvis reduction (odds ratio [OR] = 9.82, 95% confidence interval [CI]: 3.551-37.799, p < 0.001) and non-resolution of hydronephrosis (OR = 4.811, 95% CI: 1.766-13.1, p = 0.002), as late deterioration predictors. Older age at surgery (OR = 0.958, 95% CI: 0.942-0.975, p < 0.001) and higher final SRF (OR = 0.905, 95% CI: 0.855-0.958, p < 0.001) were protective against deterioration. CONCLUSION: SRF may deteriorate after puberty despite initial post-operative stability. Renal pelvis reduction, persistent hydronephrosis at 1 year and younger age at surgery are associated with increased risk of deterioration.