Validation of the Trifecta Scoring Metric in Vacuum-Assisted Mini-Percutaneous Nephrolithotomy: A Single-Center Experience.

Background: Scoring metrics to assess and compare outcomes of percutaneous nephrolithotomy (PCNL) are needed. We aim to evaluate prevalence and predictors of trifecta in a cohort of patients treated with vacuum-assisted mini-percutaneous nephrolithotomy (vmPCNL) for kidney stones. Methods: Data from 287 participants who underwent vmPCNL were analysed. Patients' and stones' characteristics as well as operative data were collected. Stone-free was defined as no residual stones. The modified Clavien classification was used to score postoperative complications. Trifecta was defined as stone-free status without complications after a single session and no auxiliary procedures. Descriptive statistics and logistic regression models tested the association between predictors and trifecta outcome. Results: After vmPCNL, 219 (76.3%) patients were stone-free, and 81 (28.2%) had postoperative complications (any Clavien). Of 287, 170 (59.2%) patients achieved trifecta criteria. Patients who achieved trifecta status had smaller stone volume (p < 0.001), a higher rate of single stones (p < 0.001), shorter operative time (p < 0.01), and a higher rate of single percutaneous tract (p < 0.01) than −trifecta patients. Trifecta status decreased with the number of calyces involved, being 77.1%, 18.8%, and 4.1% in patients with 1, 2, or 3 calyces with stones, respectively (p < 0.001). Multivariable logistic regression analysis showed that stone volume (OR 1.1, p = 0.02) and multiple calyces being involved (OR 2.8 and OR 4.3 for two- and three-calyceal groups, respectively, all p < 0.01) were independent unfavourable risk factors for trifecta after accounting for age, BMI, gender, operative time, and number of access tracts. Conclusions: Trifecta status was achieved in 6 out of 10 patients after vmPCNL. Stone distribution in multiple calyceal groups and stone volume were independent unfavourable risk factors for trifecta.

Urologists are optimistic surgeons: prevalence and predictors of discordance between intraoperative stone-free rate and cross-sectional imaging evaluation after vacuum-assisted mini-percutaneous nephrolithotomy.

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.

The comprehensive complication index as a tool for reporting the burden of complications after mini-percutaneous nephrolithotomy: is it time to leave the Clavien-Dindo classification behind?

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.