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Purpose: To evaluate the impact of vacuum-assisted mini-percutaneous nephrolithotomy (vamPCNL) vs. vacuum-cleaner mPCNL (vcmPCNL) on the rate of postoperative infectious complications in a cohort of patients with high risk factors for infections., Methods: We retrospectively analysed data from 145 patients who underwent mPCNL between 01/2016 and 12/2022. Patient's demographics, stones characteristics and operative data were collected. vamPCNL and vcmPCNL were performed based on the surgeon's preference. High-risk patients were defied as having ≥ 2 predisposing factors for infections such as a history of previous urinary tract infections, positive urine culture before surgery, stone diameter ≥ 3 cm, diabetes mellitus and hydronephrosis. Complications were graded according to modified Clavien classification. Descriptive statistics and logistic regression models were used to identify factors associated with postoperative infectious complications., Results: vamPCNL and vcmPCNL were performed in 94 (64.8%) and 51 (35.2%) cases, respectively. After surgery, infectious complications occurred in 43 (29.7%) participants. Patients who developed infectious complications had larger stone volume (p = 0.02) and higher rate of multiple stones (p = 0.01) than those who did not. Infectious complications occurred more frequently after vcmPCNL than vamPCNL (55.9% vs. 44.1%. p = 0.01) in high-risk patients. Longer operative time (p < 0.01) and length of stay (p < 0.01) were observed in cases with infectious complications. At multivariable logistic regression analysis, longer operative time (OR 1.1, p = 0.02) and vcmPCNL (OR 3.1, p = 0.03) procedures were independently associated with the risk of infectious complications post mPCNL, after accounting for stone volume., Conclusion: One out of three high-risk patients showed infectious complications after mPCNL. vamPCL and shorter operative time were independent protective factors for infections after surgery., (© 2024. The Author(s).)

Purpose: To evaluate the rate of and predictors of ureteral obstruction after mini-percutaneous nephrolithotomy (mPCNL) for kidney stones., Methods: We analyzed data from 263 consecutive patients who underwent mPCNL at a single tertiary referral academic between 01/2016 and 11/2022. Patient's demographics, stone characteristics, and operative data were collected. A nephrostomy tube was placed as the only exit strategy in each procedure. On postoperative day 2, an antegrade pyelography was performed to assess ureteral canalization. The nephrostomy tube was removed if ureteral canalization was successful. Descriptive statistics and logistic regression models were used to identify factors associated with a lack of ureteral canalization., Results: Overall, median (IQR) age and stone volume were 56 (47-65) years and 1.7 (0.8-4.2) cm 3 , respectively. Of 263, 55 (20.9%) patients showed ureteral obstruction during pyelography. Patients without ureteral canalization had larger stone volume (p < 0.001), longer operative time (p < 0.01), and higher rate of stones in the renal pelvis (p < 0.01) than those with normal pyelography. Length of stay was longer (p < 0.01), and postoperative complications (p = 0.03) were more frequent in patients without ureteral canalization. Multivariable logistic regression analysis revealed that stone volume (OR 1.1, p = 0.02) and stone located in the renal pelvis (OR 2.2, p = 0.04) were independent predictors of transient ureteral obstruction, after accounting for operative time., Conclusion: One out of five patients showed transient ureteral obstruction after mPCNL. Patients with a higher stone burden and with stones in the renal pelvis are at higher risk of inadequate ureteral canalization. Internal drainage might be considered in these cases to avoid potential complications., (© 2024. The Author(s).)

Purpose: Backflow of pathogens and endotoxins from the renal pelvis to the bloodstream is one supposed mechanism for infectious complications development after endourological stones surgery. The aim of this study is detecting to prove bacterial spread into irrigation fluid and bloodstream during percutaneous nephrolithotomy (PCNL) and to correlate these findings with clinical and microbiological parameters and infectious complications (IC)., Methods: Bladder urine culture (BUC) was retrieved before PCNL; during the procedure, 2 blood samples (BC) and an irrigation fluid sample during fragmentation (SFUC) were collected for culture. Stone culture (SC) was also obtained. Patients were evaluated post-operatively for IC., Results: Sixty-one patients were prospectively included. IC occurred in 15 patients (24.6%). SFUC was positive in 7/61 (11.5%); BC in 10/61 (16.4%). Among patients with positive BC; BUC, SFUC and SC were positive in 9 (90%), 6 (60%), and 8 (80%) cases, respectively. Out of 10 patients with positive BC, 4 developed post-operative IC. Pre-operative renal impairment (p = 0.04), intraoperative-evaluated stone residual (p = 0.02), BUC (p = 0.004), and SC (p = 0.008) were associated with IC. No correlation was found between bacterial spread in the irrigation fluid and blood and IC., Conclusion: We proved that bacteria can be detected into the irrigation fluid and blood during PCNL. This transient bacteremia appears to be unrelated to IC development., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To assess how accurate are urologists in predicting stone-free status (SFS) after vacuum-assisted mini-PCNL (vamPCNL) compared to computed tomography (CT) and clinical predictors of discordant SFS., Methods: Data from 235 patients who underwent vamPCNL were analysed. Patient's demographics, stones' characteristics and operative data were recorded. SFS was evaluated intraoperatively by the treating urologist (iSFS) and with non-contrast CT 3 months after vamPCNL (ctSFS). SFS was defined as no residual stones. Stone complexity was scored with the Guy's score. Descriptive statistics and logistic regression models were used to identify clinical factors associated with discordant SFS (namely iSFS not confirmed at CT)., Results: iSFS and ctSFS were 88.5% and 65.5%, respectively, with 54 (23%) cases resulting in discordant evaluation of SFS between the surgeon and CT imaging. Patients with discordant SFS had larger stone volume (p < 0.001), higher rate of multiple stones (p = 0.03) and higher rate of multiple calyceal groups affected by stones (p < 0.001) than those with concordant SFS. The use of flexible ureteroscopes to look for residual stones after lithotripsy was more frequently reported in cases with concordant SFS (p = 0.001). Multivariable logistic regression analysis revealed that stones in > 2 calyceal groups (OR 10.2, p < 0.001), Guy's score II (OR 5.8, p < 0.01) and not using flexible ureteroscopes after lithotripsy (OR 2.9, p = 0.02) were independent predictors of discordant SFS., Conclusion: One out of five patients is erroneously considered SF after vamPCNL. Urologist should carefully evaluate patients with multiple calyceal stones and consider using flexible ureteroscopes to complete lapaxy of migrated fragments in order to improve their prediction of SFS., (© 2022. The Author(s).)

Purpose: To validate the comprehensive complication index (CCI) for mini-percutaneous nephrolithotomy (mPCNL)., Methods: Data from 287 patients who underwent mPCNL were analyzed. Complications after mPCNL were classified using both the CCI and the Clavien-Dindo classification (CDC). Descriptive statistics and linear/logistic regression analyses detailed the association between clinical predictors and mPCNL outcomes., Results: After mPCNL, 83 (28.9%) patients had complications, of which 12 (4.2%) patients with multiple complications had a higher CCI score compared to the traditional CDC system accounting only for the highest grade. The CCI enabled a more accurate prediction of length of stay (LOS) than CDC (CCI: r = 0.32; p < 0.01 vs. CDC: r = 0.26; p = 0.01). Patients with multiple complications had higher stone volume (p = 0.02), longer operative time and LOS (all p < 0.01). A higher rate of post-operative hospital readmission (33.3% vs. 9.9%, p = 0.02) and lower rate of stone free (33.3% vs. 64.7%, p = 0.04) were found in patients with multiple complications than in those with single complication. Linear regression analysis revealed that multiple complications were associated with longer LOS (p < 0.001) after accounting for BMI and stone volume. Similarly, having multiple complications was associated with fivefold higher risk of readmission (p = 0.02)., Conclusion: The CCI is a valuable metric for assessing post-operative complications after mPCNL. The cumulative CCI is a better predictor of LOS than the CDC for mPCNL. Minor complications not captured by the highest CDC score are relevant since patients with multiple complications have longer LOS and higher rate of readmission than those with single ones., (© 2022. The Author(s).)

Purpose: To perform a cost analysis between vacuum-assisted percutaneous nephrolithotomy (vmPCNL) and minimally invasive PCNL (MIP) and explore potential predictors of costs associated with the procedures., Methods: We analyzed data from 225 patients who underwent vmPCNL or MIP at a single tertiary referral academic center between January 2016 and December 2020. We collected patients' demographics, peri-and postoperative data and detailed expense records. After propensity score matching, 108 (66.7%) vmPCNL and 54 (33.3%) MIP procedures were analyzed. Descriptive statistics assessed differences in clinical and operative parameters. Univariable and multivariable linear regression models tested the association between clinical variables and costs., Results: Operative time (OT) was shorter for vmPCNL, and the use of additional instruments to complete litholapaxy was more frequent in MIP (all p ≤ 0.01). Length of stay (LOS) was longer for MIP patients (p = 0.03) and the stone-free (SF) rate was higher after vmPCNL (p = 0.04). The overall instrumentation cost was higher for vmPCNL (p < 0.001), but total procedural costs were equivalent (p = 0.9). However, the overall cost for the hospitalization was higher for MIP than vmPCNL (p = 0.01). Univariable linear regression revealed that patient's comorbidities, OT, any postoperative complication and LOS were associated with hospitalization costs (all p < 0.001). Multivariable linear regression analysis revealed that LOS and OT were associated with hospitalization costs (all p < 0.001), after accounting for vmPCNL procedure, patients' comorbidities, and complications., Conclusion: vmPCNL may represent a valid option due to clinical and economic benefits. Shorter OT, the lower need for disposable equipment and the lower complication rate reduced procedural and hospitalization costs., (© 2021. The Author(s).)