Stones hounsfield unit value and predictors of urinary leakage after PCNL

Abstract

Background To evaluate the predictive factors of urinary leakage (UL) following percutaneous nephrolithotomy (PNL) and to investigate the relationship between Hounsfield unit (HU) of stone and UL. Methods We retrospectively reviewed the data of 728 patients who underwent PNL between January 2012 and January 2017. In total, 396 patients were eligible for the study. Patient demographics, renal factors, stone properties and operative details were collected. The association between UL and these variables were assessed by univariate and multivariate analysis. Results There was no statistically significant correlation considering age, body mass index and the presence of hypertension. The presence of diabetes mellitus (DM) was significantly correlated with UL (p < 0.001). Kidney related factors such as parenchymal thickness, hydronephrosis grade (HN), previous stone treatment, and stone related factors, such as stone surface area, stone burden, stone localization and HU value of stone, were found to affect UL status significantly (p < 0.001). Operation time, fluoroscopy time, treatment outcome, j stent use, percutenous nephrostomy (PCN) catheter stay time and the hospitalization time also had significant effect on UL (p < 0.001). Multivariable logistic analysis showed that presence of DM, parenchymal thickness, HU values, HN, operation time, j stent use, and PCN catheter stay time are independently related with UL following PCNL. Moreover, we determined a HU cut-off value of 933 with ROC analysis, which demostrated 84.9% sensitivity and 67.1% specificity for predicting UL. Conclusion This study has shown that we are more likely to encounter postoperative UL in stones with higher HU values. Therefore, we suggest clinicians to inform patients with this type of kidney stones about the probable complication of UL.