Introduction

Our aims were to assess the impact of waiting times on the split renal function after pyeloplasty and to determine the value of repeated MAG3 renograms after the procedure. We also compared the outcomes of pyeloplasty in those with split function >30% compared to those with poorly functioning kidney (split function ≤30%)_x000D_ _x000D_

Methods

Retrospective analysis of all cases that underwent primary pyeloplasty in four centres in the UK from 2008 to 2015. We excluded those < 16 years old, single kidney, bilateral UPJO and other congenital renal abnormalities. We also excluded patients that did not have FU imaging. A change of >5% split function on renogram was considered significant. Logistic regression analysis was used to determine the impact of waiting times on split renal function after pyeloplasty

Results

175 pts were included. The mean age was 41.2 years with a mean length of FU of 573 days. The mean pre-op split renal function (available in 161 cases) was 39.4% (SD 10.5). 35 pts had split function ≤30%. The mean waiting time from presentation to operation was 207 days (SD 277). The mean interval between pyeloplasty and 1st post-op renogram was 118 days (SD 73). The second post-op renogram was performed at a mean interval of 355 days (SD 193) following the 1st scan _x000D_ 89 pts had split function documented in one pre-op and two post-op renograms. Seventy-two cases (81%) showed stable or improved function on their first post-op renogram (58 stable, 14 improved) and the second post-op renogram showed renal function remained stable or improved in 68 (95%). In the remaining 4 pts, the split function only marginally deteriorated (average reduction of -7%). Of the 17 cases with worsening renal function on the 1st post-op renogram, the split function continued to deteriorate in only 2 cases. Both of which remained obstructed on the both 1st and 2nd post-op renograms. _x000D_ Pts that had worsening split function post-op had a longer waiting time for their procedure (the majority of those that waited over 200 days had poor functional outcomes, p= 0.01) _x000D_ Pain was the most common presenting symptom (80% of cases). 79.2% of these pts had improved symptoms post-op. Those with split function of ≤30% showed higher levels of pain post op (26.7%) compared to those with better function (20.8%) but this was not statistically significant (p=0.6)_x000D_

Conclusions

Longer waiting times from presentation to definitive treatment appear to have a significant negative impact on split renal function post-pyeloplasty. The majority of patients received functional and symptomatic improvement post-pyeloplasty but there was no significant difference in outcome between those with split renal function of ≤30% compared those with better renal function. Those with favourable results on the 1st post-operative renogram (no obstruction with stable or improved function), may not require further imaging

Funding

none