Poor split renal function and age in adult patients with ureteropelvic junction obstruction do not impact functional outcomes of pyeloplasty

Introduction: To examine if poor preoperative split renal function (SRF) and age influence pyeloplasty outcomes in adults with ureteropelvic junction obstruction (UPJO). Materials and methods: We retrospectively reviewed our pyeloplasty experience in adults with UPJO from 2004 to 2014. Patients with solitary kidneys or missing renal scans were excluded. Renal scans were performed at 6 weeks, 8 months, and 20-24 months postoperatively. Demographics, operative approaches, and pre and postoperative SRF and diuretic half-times (T1/2) were obtained. Patients were stratified by preoperative SRF (≤ or > 25%) and age. Cox regression analyses were performed to explore predictors for stability or improvement of SRF. Results: A total of 139 patients met the study criteria: 15 and 124 with preoperative SRF ≤ 25% and > 25%, respectively. Median follow up was 11 months, 12.9% of patients experienced worsening, 67.6% stability, and 19.4% improvement in SRF at last follow up. Median change in SRF was similar between groups; however, patients with lower preoperative SRF more frequently experienced improvement or worsening of SRF (p = 0.045). Failure rates (need for additional surgery) were comparable (p = 1.000). No significant differences were observed in SRF dynamicity when stratified by age (p = 0.120). On univariate Cox analysis, older age was predictive of stability or improvement in SRF across the entire cohort (HR 1.013, p = 0.016), while preoperative SRF was not (HR 1.007, p = 0.429). Conclusions: Poor SRF (≤ 25%) and age were not associated with worse outcomes after pyeloplasty for UPJO. Our results suggest that older adults with UPJO and patients with poor ipsilateral SRF should not be excluded from pyeloplasty.