Factors impacting post-nephrostomy-tube removal urine leak after percutaneous nephrolithotomy: does the calyx of access make a difference?

Abstract

BackgroundThe aim of this study was to identify the factors that impact the post- percutaneous nephrolithotomy (PCNL) urine leak (UL) following nephrostomy tube removal and to assess if the calyx of entry made any difference.Materials and methodsIn this retrospective study, from April 2016 to May 2019, all the patients undergoing conventional percutaneous nephrolithotomy by a single 24 Fr access with complete stone clearance were evaluated. Patients with urine leak for > 4 h after nephrostomy tube removal were included in the urine leak group (n = 18), while the non-urine leak group (n = 60) comprised patients with urine leak for < 4 h. These groups were compared for demographic, renal, stone-related and peri-operative factors with special stress on calyx of access.ResultsThe urine leak group had significantly older (mean 48 vs. 31 years, p = 0.003) patients with a higher proportion of diabetes mellitus (33% vs. 11%, p = 0.03). They also had a significantly greater (grade ≥ 3) hydronephrosis (55.5% vs. 10%, p < 0.001) and significantly reduced cortical thickness (mean 6.4 vs. 10.3 mm, p = 0.001). They had a nephrostomy tube in situ post-operatively for a longer duration (mean 52.3 vs. 34.5 h, p = 0.002). Interestingly 100% leaks happened from the middle/lower calyx tract and none from the upper calyceal access (p < 0.001). On multivariable regression analysis, grade ≥ 3 hydronephrosis with thin cortex, middle/lower calyceal access and keeping the nephrostomy tube for prolonged duration post-operatively were independent predictors of urine leak. There was no risk of leak from upper calyx access.ConclusionThere is negligible risk of urine leak from upper calyx access so the possibility of hydrothorax after nephrostomy tube removal is minimal.