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Introduction: We aim to compare transperitoneal (TP) and retroperitoneal (RP) robotic partial nephrectomy (RPN) in obese patients. Obesity and RP fat can complicate RPN, especially in the RP approach where working space is limited. Materials and Methods: Using a multi-institutional database, we analyzed 468 obese patients undergoing RPN for a renal mass (86 [18.38%] RP, 382 [81.62%] TP). Obesity was defined as body mass index ≥30 kg/m 2 * . A 1:1 propensity score matching was performed adjusting for age, previous abdominal surgery, tumor size, R.E.N.A.L nephrometry score, tumor location, surgical date, and participating centers. Baseline characteristics and perioperative and postoperative data were compared. Results: In the propensity score-matched cohort, 79 (50%) TP patients were matched with 79 (50%) RP patients. The RP group had more posterior tumors (67 [84.81%], RP versus 23 [29.11%], TP; P  < .001), while the other baseline characteristics were comparable. Warm ischemia time (interquartile range; 15 [10, 12], RP versus 14 [10, 17] minutes, TP; P  = .216), operative time (129 [116, 165], RP versus 130 [95, 180] minutes, TP; P  = .687), estimated blood loss (50 [50, 100], RP versus 75 [50, 150] mL, TP; P  = .129), length of stay (1 [1, 1], RP versus 1 [1, 2] day, TP; P  = .319), and major complication rate (1 [1.27%], RP versus 3 [3.80%], TP; P  = .620) were similar. No significant difference was observed in positive surgical margin rate and delta estimated glomerular filtration at follow-up. Conclusion: TP and RP RPN yielded similar perioperative and postoperative outcomes in obese patients. Obesity should not be a factor in determining optimal approach for RPN.

Introduction: Highly complex renal masses pose a challenge to urologic surgeons' ability to perform robotic partial nephrectomy (RPN). Given the increased utilization of the robotic approach for small renal masses, we sought to characterize the outcomes and determine the safety and feasibility of RPN for complex renal masses from our large multi-institutional cohort., Methods: We performed a retrospective analysis of patients with R.E.N.A.L. Nephrometry Scores ≥10 who underwent RPN in our multi-institutional cohort (N = 372). Baseline demographic, clinical and tumor related characteristics were evaluated with the primary endpoint of trifecta achievement (defined as negative surgical margin, no major complications, and warm ischemia time ≤25 min). Relationships between variables were assessed using the chi-square test of independence, Fisher exact test, Mann-Whitney U test, and Kruskal Wallis test. Logistic regression was used to evaluate the relationship between baseline characteristics and trifecta achievement., Results: Of 372 patients in the study, mean age was 58 years, and median BMI was 30.49 kg/m 2 . The median tumor size was 4.3 cm (3.0-5.9 cm). Most of the patients had R.E.N.A.L. scores of 10 (n = 253; 67.01%). Overall, trifecta was achieved in 72.04% of patients. Stratifying intraoperative and postoperative outcomes by R.E.N.A.L. scores, there was no significant difference in trifecta achievement, operative time, warm ischemia time (WIT), open conversion, major complication, or positive margin rates. Length of hospital stay was significantly longer for higher R.E.N.A.L. scores (median days 2 vs. 1, P = 0.012). Multivariate analyses for factors associated with trifecta achievement concluded that age and baseline eGFR were independently associated with trifecta achievement., Conclusion: RPN is a safe and reproducible procedure for complex tumors with R.E.N.A.L. Nephrometry scores ≥10. Our results suggest excellent rates of trifecta achievement and short-term functional outcomes when performed by experienced surgeons. Long-term oncological and functional evaluation are needed to further support this conclusion., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

We aim to describe the perioperative and oncological outcomes for salvage robotic partial nephrectomy (sRPN) and salvage robotic radical nephrectomy (sRRN). Using a prospectively maintained multi-institutional database, we compared baseline clinical characteristics and perioperative and postoperative outcomes, including pathological stage, tumor histology, operative time, ischemia time, estimated blood loss (EBL), length of stay (LOS), postoperative complication rate, recurrence rate, and mortality. We identified a total of 58 patients who had undergone robotic salvage surgery for a recurrent renal mass, of which 22 (38%) had sRRN and 36 (62%) had sRPN. Ischemia time for sRPN was 14 min. The median EBL was 100 mL in both groups (p = 0.581). One intraoperative complication occurred during sRRN, while three occurred during sRPN cases (p = 1.000). The median LOS was 2 days for sRRN and 1 day for sRPN (p = 0.039). Postoperatively, one major complication occurred after sRRN and two after sRPN (p = 1.000). The recurrence reported after sRRN was 5% and 3% after sRPN. Among the patients who underwent sRRN, the two most prevalent stages were pT1a (27%) and pT3a (27%). Similarly, the two most prevalent stages in sRPN patients were pT1a (69%) and pT3a (6%). sRRN and sRPN have similar operative and perioperative outcomes. sRPN is a safe and feasible procedure when performed by experienced surgeons. Future studies on large cohorts are essential to better characterize the importance and benefit of salvage partial nephrectomies., (© 2023. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

Objective: To describe the most recent surgical, functional, and oncological outcomes of RPN utilizing one of the largest, prospectively maintained, multi-institution consortium of patients undergoing robotic renal surgery., Materials and Methods: Data was obtained from a prospectively maintained multi-institutional database of patients who underwent RPN for clinically localized kidney cancer between 2018 and 2022 by 9 high-volume surgeons. Demographic and tumor characteristics as well as operative, functional, and oncological outcomes were queried., Results: A total of 2836 patients underwent RPN. Intraoperative, postoperative, and 30-day major complication rates were 2.68%, 11.39%, and 3.24%, respectively. Median tumor size was 3.0 cm. Tumors with low complexity had a shorter median operative time, lower median EBL, shorter median ischemia time, lower postoperative complication rate, and lower decline in renal function There was no significant difference between tumor complexities with respect to the rate of conversion to radical nephrectomy, conversion to open, major complications, and positive margins. Lower BMI, smaller clinical tumor size, lower tumor complexity, and higher baseline eGFR were significantly associated with trifecta achievement., Conclusion: Patient BMI, baseline eGFR, and tumor characteristics such as size and complexity are the most important predictors of trifecta achievement. Patients with complex tumors should be counseled that they are at increased risk of complications and worsening renal function after robotic partial nephrectomy., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Introduction: Retroperitoneal robotic partial nephrectomy (RPN) has been shown to have comparable outcomes to the transperitoneal approach for renal tumors. However, this may not be true for completely endophytic tumors as they pose significant challenges in RPN with increased complication rates. Hence, we sought to compare the safety and feasibility of retroperitoneal RPN to transperitoneal RPN for completely endophytic tumors., Methods: We performed a retrospective analysis of patients who underwent RPN for a completely endophytic renal mass using either transperitoneal or retroperitoneal approach from our multi-institutional database (n = 177). Patients who had a solitary kidney, prior ipsilateral surgery, multiple/bilateral tumors, and horseshoe kidneys were excluded from the analysis. Overall, 156 patients were evaluated (112 [71.8%] transperitoneal, 44 [28.2%] retroperitoneal). Baseline characteristics, perioperative and postoperative data were compared between the surgical transperitoneal and retroperitoneal approach using Chi-square test, Fishers exact test, t test, Mood median test and Mann Whitney U test., Results: Of the 156 patients in this study, 86 (56.9%) were male and the mean (SD) age was 58 (13) years. Baseline characteristics were comparable between the 2 approaches. Compared to transperitoneal approach, retroperitoneal approach had similar ischemia time (19.6 [SD = 7.6] minutes vs. 19.5 [SD = 10.2] minutes, P = 0.952), operative time (157.5 [SD = 44.8] minutes vs. 160.2 [SD = 47.3] minutes, P = 0.746), median estimated blood loss (50 ml [IQR: 50, 150] vs. 100 ml [IQR: 50, 200], P = 0.313), median length of stay (1 [IQR: 1, 2] day vs. 1 [IQR: 1, 2] day, P = 0.126) and major complication rate (2 [4.6%] vs. 3 [2.7%], P = 0.621). No difference was observed in positive surgical margin rate (P = 0.1.00), delta eGFR (P = 0.797) and de novo chronic kidney disease occurrence (P = 1.000)., Conclusion: Retroperitoneal and transperitoneal RPN yielded similar perioperative and functional outcomes in patients with completely endophytic tumors. In well-selected patients with purely endophytic tumors, either a retroperitoneal or transperitoneal approach could be considered without compromising perioperative and postoperative outcomes., Competing Interests: Conflict of interest None., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: The aim of this study was to evaluate the association between tumor complexity based on RENAL nephrometry score and complications., Methods: We retrospectively identified 2555 patients who underwent RPN for renal cell carcinoma. Major complication was defined as Clavien Grade ≥3. The relationship between baseline demographic, clinical characteristics, perioperative and postoperative outcomes, and tumor complexity were assessed using χ2 test of independence, Fisher's Exact Test and Kruskal Wallis Test. An unadjusted and adjusted logistic regression model was used to assess the relationship between major complication and demographic, clinical characteristics, and perioperative outcomes., Results: There was a significant relationship between tumor complexity and WIT (P<0.001), operative time (P<0.001), estimated blood loss (P<0.001), and major complication (P=0.019). However, there was no relationship with overall complications (P=0.237) and length of stay (LOS) (P=0.085). In the unadjusted model, higher tumor complexity was associated with major complication (P=0.009). Controlling for other variables, there was no significant difference between major complication and tumor complexity (low vs. moderate, P=0.142 and high, P=0.204). LOS (P<0.001) and operative time (P=0.025) remained a significant predictor of major complication in the adjusted model., Conclusions: Tumor complexity is not associated with an increase in overall or major complication rate after RPN. Experience in high-volume centers is demonstrating a standardization of low complications rates after RPN independent of tumor complexity.

Purpose: Intravesical recurrence (IVR) after radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC) has an incidence of approximately 20%-50%. Studies to date have been composed of mixed treatment cohorts-open, laparoscopic and robotic. The objective of this study is to assess clinicopathological risk factors for intravesical recurrence after RNU for UTUC in a completely minimally invasive cohort., Materials and Methods: We performed a multicenter, retrospective analysis of 485 patients with UTUC without prior or concurrent bladder cancer who underwent robotic or laparoscopic RNU. Patients were selected from an international cohort of 17 institutions across the United States, Europe and Asia. Univariate and multiple Cox regression models were used to identify risk factors for bladder recurrence., Results: A total of 485 (396 robotic, 89 laparoscopic) patients were included in analysis. Overall, 110 (22.7%) of patients developed IVR. The average time to recurrence was 15.2 months (SD 15.5 months). Hypertension was a significant risk factor on multiple regression (HR 1.99, CI 1.06; 3.71, p=0.030). Diagnostic ureteroscopic biopsy incurred a 50% higher chance of developing IVR (HR 1.49, CI 1.00; 2.20, p=0.048). Treatment specific risk factors included positive surgical margins (HR 3.36, CI 1.36; 8.33, p=0.009) and transurethral resection for bladder cuff management (HR 2.73, CI 1.10; 6.76, p=0.031)., Conclusions: IVR after minimally invasive RNU for UTUC is a relatively common event. Risk factors include a ureteroscopic biopsy, transurethral resection of the bladder cuff, and positive surgical margins. When possible, avoidance of transurethral resection of the bladder cuff and alternative strategies for obtaining biopsy tissue sample should be considered.

Following partial nephrectomy (PN), it is important to prevent any deterioration in estimated glomerular filtration rate (eGFR). At present there are no evidence-based recommendations on when a nephrology consultation should be requested and how to adjust postoperative management when the risk of renal function decline is high. In an effort to address this void, we used our previously published nomogram to define risk groups for a significant decline in eGFR at 3-15 mo after PN. We used the nomogram-derived probability as the independent variable for the classification and regression tree and identified four risk groups: low (0-10%), intermediate (10-21%), high (21-65%), and very high (65-100%). Overall, 336 (34%), 386 (39%), 243 (24%), and 34 (4%) patients fell in the low, intermediate, high, and very high risk groups, respectively. The rates of significant eGFR decline across the low, intermediate, high, and very high risk groups were 4%, 14%, 29%, and 79%. With the low risk category as a reference, the hazard ratio for eGFR decline was 3.21 (95% confidence interval [CI] 1.83-5.64) for the intermediate, 7.80 (95% CI 4.52-13.48) for the high, and 27.24 (95% CI 13.8-53.8) for the very high risk group (all p<0.001). These prognostic risk categories can be used to design postoperative follow-up schedules. A multidisciplinary approach can be considered for patients at high and very high risk of eGFR decline. PATIENT SUMMARY: We propose a new stratification system to identify individuals at high risk of a decline in renal function after robotic partial nephrectomy., (Copyright © 2019 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Introduction: Closed drains have traditionally been placed after partial nephrectomy because of risks of bleeding and urine leak. We sought to study the safety of a nonroutine drain (NRD) approach after transperitoneal robotic partial nephrectomy (RPN). Patients and Methods: From a multi-institutional database, we have analyzed the data of 904 patients who underwent RPN. Five hundred forty-six (60.40%) patients underwent RPN by a surgeon who routinely placed drains. Three hundred fifty-eight (39.60%) patients underwent RPN by a surgeon who did not routinely placed drains. Perioperative outcomes, length of stay (LOS), and readmission rates were compared between the two groups. Baseline characteristics, perioperative, and postoperative outcomes were compared using Mann-Whitney U test, chi-square test, and Fisher's exact test. Results: Patients in the NRD group were more likely to have higher body mass index (30.10 kg/m 2 vs 28.07 kg/m 2 ; P  < 0.001), higher tumor size (3.0 cm vs 2.5 cm; P  = 0.001), and higher renal score (8 vs 7; P  < 0.001). Rate of transfusion (0.00% NRD vs 0.56% RD; P  = 0.157) and overall complication (7.33% NRD vs 7.82% RD; P  = 0.782) were comparable. Median hospital stay is 1 day for both groups. Readmission rate was also similar (0.55% NRD vs 1.40% RD; P  = 0.279). In a multivariable analysis, NRD approach was associated with shorter length of hospital stay (incidence rate ratio [IRR] - 0.72, P  < 0.001). Conclusion: An NRD approach for RPN yielded a decreased LOS and similar perioperative outcomes. Placement of surgical drains should be based on individual circumstances, and not required on a routine basis.

Hilar tumors pose unique challenges during partial nephrectomy. We present the characteristics and outcomes of 263 patients with hilar tumors undergoing robot-assisted partial nephrectomy (RPN) in the largest series to date. Perioperative, pathologic, functional, and oncological outcomes were compared between 1467 (84.8%) patients with a non-hilar tumor and 263 (15.2%) patients with a hilar tumor undergoing RPN. Variables were compared in univariable (unadjusted) analysis and using multivariable linear, logistic, poisson, cox proportional hazards and linear mixed effects regression models adjusting for tumor diameter and RENAL Nephrometry score. Hilar tumors were larger (3.7 vs. 3.0 cm, p < 0.001) and more complex (RENAL Score 9 vs. 7, p < 0.001), leading to longer operative time (186 vs. 161 min, p < 0.001), ischemia time (18 vs. 15, p < 0.001), greater blood loss (150 vs. 100 ml, p < 0.001), eGFR decline at discharge (∆ = 3.9%, p = 0.035) and eGFR decline per month up to 36 months post-RPN (β = - 0.25; p = 0.017). In multivariable analysis, hilar tumors were only associated with a 10% increase in operative time (p ≤ 0.001) and marginally worse eGFR decline over time (β = - 0.19, p = 0.076), with no differences in other outcomes analyzed including ischemia time, blood loss, complication rate, recurrence-free survival, or eGFR decline at discharge. Although hilar tumors were found to be larger and more anatomically complex, there were only marginal differences in outcome when compared to non-hilar tumors. A hilar renal tumor should be considered for partial nephrectomy when feasible without an expected increase in complications or adverse events.

Objective: To evaluate the effect of obesity and overweight on surgical, functional, and survival outcomes in patients with large kidney masses after minimally invasive surgery. Materials and Methods: Within a multicenter multinational dataset, patients found to have ≥cT 2 renal mass and treated with minimally invasive (laparoscopic or robotic) kidney surgery (radical or partial nephrectomy) during the period 2003 to 2017 were abstracted. They were stratified according to the body mass index classes as normal weight (18.5-24.9 kg/m 2 ), overweight (25.0-29.9 kg/m 2 ), and obese (≥30.0 kg/m 2 ). Mixed models and Cox proportional hazard regression tested differences in complication rates, estimated glomerular filtration rate (eGFR) change over time, overall mortality (OM), and disease recurrence (DR) rates. Results: Of 812 patients, 30.6% were normal weight, 42.7% were overweight, and 26.7% obese. Overweight (odds ratio 0.82, 95% confidence interval [CI]: 0.51-1.31, p  = 0.406) and obese patients (OR: 0.81, 95% CI: 0.44-1.47, p  = 0.490) experienced similar complication rates than normal weight. Moreover, no statistically significant differences in eGFR were found for overweight ( p  = 0.129) or obese ( p  = 0.166) patients compared to normal weight. However, higher OM rates were recorded in overweight (hazard ratio [HR] 3.59, 95% CI: 1.03-12.51, p  = 0.044), as well as in obese, patients (HR 7.83, 95% CI: 2.20-27.83, p  = 0.002). Similarly, higher DR rates were recorded in obese (HR 2.76, 95% CI: 1.40-5.44, p  = 0.003) patients. Conclusions: Obese and overweight patients do not experience higher complication rates or worse eGFR after minimally invasive kidney surgery, which therefore can be deemed feasible and safe also in this subset of patients. Nevertheless, obese and overweight patients seem to carry a higher risk of OM, and therefore, they should undergo a strict follow-up after surgery.

Objectives: To evaluate the feasibility of postoperative day 1 (POD1) discharge after robotic partial nephrectomy (RPN) and to determine whether a protocol targeting a shorter length of stay (LOS) is associated with any difference in the rate of postoperative complications. Materials and Methods: We reviewed a prospectively maintained, multi-institutional database of patients who underwent RPN from September 2013 to September 2016. Three of the six participating surgeons used a protocol that targeted discharge on POD1, whereas three surgeons did not. Patient characteristics and postoperative complication rates between the two groups were compared. Results: A total of 665 patients were included, 455 of whom were treated by surgeons utilizing a POD1 discharge protocol, whereas 210 were not. The mean LOS for those in the POD1 protocol group was 1.13 days vs 2.02 days in the non-protocol group. Between groups, there were no differences in age ( p  = 0.098), body mass index ( p  = 0.164), tumor size ( p  = 0.502), or R.E.N.A.L. Nephrometry score ( p  = 0.974), but POD1 discharge protocol patients had higher age-adjusted Charlson comorbidity score (4 vs 2, p  = 0.033), were less likely to have a hilar tumor (15.9% vs 23.1%, p  = 0.03), and had a larger percent decrease in discharge estimated glomerular filtration rate (-15.9% vs -7.1%, p  < 0.001). There were no differences in the rates of overall ( p  = 0.715), major ( p  = 0.164), medical ( p  = 0.089), or surgical complications ( p  = 0.301) or in complications by the Clavien-Dindo category ( p  = 0.13). Conclusion: Discharge on POD1 after RPN is feasible, reproducible by different surgeons, and not associated with an increased risk of postoperative complications.

Background: Performing partial nephrectomy (PN) on a cT1 tumor, which postoperatively is upgraded to pT3a can possibly lead to compromise of cancer specific mortality. We therefore aimed to identify risk factors for pathologic T3a upstaging of cT1 tumors and to analyze the association between upstaging, positive surgical margins (PSM) and overall survival (OS)., Methods: The present study included patients who underwent PN for a clinically localized T1 renal mass from two datasets: 1) 1298 patients from a prospectively maintained multi-center database (MCDB); and 2) 7940 patients from the National Cancer Database (NCDB). Multivariable logistic regression models within each cohort were used to identify predictors of cT1 to pT3a upstaging and its association with PSM. Cox proportion hazards regression models were used to compare overall survival in the NCDB cohort., Results: The rate of pT3a upstaging was 5.7% (N.=74) in the MCDB and 1.9% (N.=156) in the NCDB cohort. Older age (MCDB OR=1.04, P=0.001; NCDB OR=1.04, P=0.001) and larger tumor size (MCDB OR=1.89, P<0.001; NCDB OR=1.38, P<0.001) increased the likelihood of upstaging. PSM was found to be more likely for pT3a upstaged patients in both cohorts (MCDB 14.9% vs. 3.5%, P<0.001; NCDB 14.8% vs. 8.3%, P=0.006), even when adjusting for tumor size. At short term follow-up (NCDB median follow-up 27.3 months), pT3a upstaging was associated with worse OS in univariable (HR=1.89; 95% CI=1.00, 3.55; P=0.049) but not multivariable analysis (HR=1.63; 95% CI=0.86, 3.08; P=0.131). OS was 93.0% vs. 95.8% at 3 years for those with and without pT3a upstaging, respectively., Conclusions: Larger tumor size and increased age are associated with pathological upstaging to T3a for clinical T1 tumors treated with partial nephrectomy. Steps to improve identification of occult pT3a disease are necessary as its occurrence significantly increased the likelihood of a PSM, both in a high-volume multicenter cohort, as well as, a national data registry.

Objective: To determine the safety and efficacy of performing partial nephrectomy (PN) on patients with high nephrometry score tumors., Patients and Methods: We used a prospectively maintained multi-institutional kidney cancer database to identify 144 patients with R.E.N.A.L. nephrometry score ≥10 who underwent PN for a cT1-cT2 renal mass. Baseline demographics and clinical characteristics, tumor characteristics, perioperative, and pathological outcomes were analyzed and reported. Trifecta achievement, defined by warm ischemia time <25 minutes, no perioperative complications, and negative surgical margins, was the primary outcome. We assessed the relationship of baseline clinical and tumor characteristics data to trifecta achievement and perioperative complications., Results: Baseline median eGFR was 84.57 ml/min/1.73 m 2 , with 119 (84.39%) patients having normal baseline kidney function. The median clinical tumor size was 4.95 cm, with 74 (51.75%) being completely endophytic and 58 (41.73%) located on the hilum. The median ischemia time was 20 minutes. Median estimated blood loss was 150 ml. Twelve patients (8.33%) had intraoperative complications. No patient had a conversion to open surgery. Postoperative, perioperative, and major complication rate were 10.42%, 17.3%, and 2.34% respectively. Thirty-six patients (37.89%) developed postoperative acute kidney injury and 28 (20.90%) developed new-onset CKD at a median follow-up of 6 months. Eight patients (5.56%) had a positive surgical margin. Trifecta was achieved in 89 (61.81%) patients. There was no significant difference in baseline, clinical, and tumor characteristics between those that achieved trifecta and in those where trifecta was not. Pathologic tumor stage was the only factor significantly associated with trifecta achievement (P = 0.025)., Conclusion: In treating complex renal tumors, PN should be performed when possible. Although this remains a challenging procedure, with experience and appropriate case selection, the trifecta outcome can be achieved in a significant number of patients with high renal score lesions., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Acute Kidney Injury (AKI) is a common occurrence after partial nephrectomy and is a significant risk factor for chronic kidney disease. We aimed to create a model that predicts postoperative AKI in patients undergoing robot-assisted partial nephrectomy (RAPN)., Methods: We identified 1,190 patients who underwent RAPN between 2008 and 2017 from a multicenter database. AKI was defined as a >25% reduction in eGFR from pre-RAPN to discharge. A nomogram was built based on a binary logistic regression that ultimately included age, sex, BMI, diabetes, baseline eGFR, and RENAL Nephrometry score. Internal validation was performed using the leave-one-out cross validation. Calibration was graphically investigated. The decision curve analysis was used to evaluate the net clinical benefit; a classification tree was used to identify risk categories. The same model was fit adding ischemia time during RAPN., Results: Median (IQR) age at surgery was 61 (50, 68) years; 505 (42%) patients were female, while 685 (58%) were male. Median (IQR) ischemia time during RAPN was 14 (10, 18) min. postoperative AKI occurred in 274 (23%) patients. All variables fitted in the model emerged as predictors of AKI (all P ≤ 0.005) and all were considered to build a nomogram. After internal validation, the area under the curve was 73%. The model demonstrated excellent calibration and improved clinical risk prediction at the decision curve analysis. In the low, intermediate, and high-risk groups the postoperative AKI rates were: 10%, 30%, and 48%, respectively. Adding ischemia time to the preoperative model fit the data better (likelihood ratio test: P < 0.001) and yielded an incremental area under the curve of 3% (95% confidence interval: 1, 5%) CONCLUSION: We developed a nomogram that accurately predicts AKI in patients undergoing RAPN. This model might serve (1) in the preoperative setting: for counsel patients according to their preoperative AKI risk (2) in the immediate postoperative: for identifying patients who would benefit from an early multidisciplinary evaluation, when considering also ischemia time., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: As the prevalence of obesity increases worldwide, an increasing proportion of surgical candidates have an elevated body mass index (BMI), with associated metabolic syndrome. Yet there exists limited evidence regarding the effect of elevated BMI on surgical outcomes in robotic surgeries. We examined whether obese patients had worse perioperative outcomes and postoperative renal function after robotic partial nephrectomies (RPNs). Materials and Methods: We performed a multi-institutional analysis of 1770 patients who underwent RPNs between 2008 and 2015, allowing time for the data set to mature. Associations between BMI, as a continuous and categorical variable, and perioperative outcomes, acute kidney injury (AKI, >25% reduction in estimated glomerular filtration rate [eGFR]) at discharge, and change in eGFR per month were analyzed. AKI and eGFR were evaluated using multivariable logistic and linear regression models adjusted for confounders, including age, Charlson comorbidity index, tumor size, and the identity of the surgeon. Results: In total 45.2% ( n  = 529) of patients were found to be obese, with a greater prevalence of hypertension and diabetes in overweight and obese patients. Obese patients were more likely to have malignant tumors (>77% vs 68%, p  < 0.001) and trended toward having larger tumors (3.0 cm vs 2.8 cm; p  = 0.061). Heavier patients required longer operative times (166-196 minutes vs 155 minutes; p  < 0.001), although equivalent warm ischemia times ( p  = 0.873). Obesity did not correlate with an increased complication rate ( p  > 0.05). On multivariable analysis, obesity (odds ratio [OR] = 1.81; p  = 0.031), male sex (OR = 1.54; p  = 0.028), and larger tumor size (OR = 1.23; p  < 0.001) were associated with a significant increase in the likelihood of AKI at discharge. BMI above normal weight was not associated with greater eGFR decline per month post-RPN. Conclusions: Obesity was associated with equivalent perioperative outcomes and long-term renal function. Further research is warranted into how obesity and metabolic syndrome may foster a more aggressive tumor environment. RPN appears to be an equally safe operative option for patients regardless of obesity status.

To evaluate peri- and post-operative outcomes after robotic partial nephrectomy (RPN) in patients with a solitary kidney. A multi-institutional database of 1868 patients was used to identify 35 patients with a solitary kidney who underwent RPN at six different centers from 2007 to 2016. Peri-operative outcomes were summarized with descriptive statistics. We assessed the change in eGFR over time with a linear mixed-effects model. Median operative time, ischemia time, and estimated blood loss were 172 min, 16 min, and 113 mL, respectively. There were no positive surgical margins. The median length of stay was 1 day (range 1-7), and over half (54.3%) of patients were discharged one post-operative day 1. Seven post-operative complications occurred in six patients (17.1%); of which four were Clavien I, two were Clavien II, and one was Clavien III. The linear decline in eGFR up to 24 month post-RPN was marginal and not significant (ß = - 0.14; 95% CI = - 0.51, 0.23; p = 0.453), with predicted mean eGFR decreasing from 59.2 to 55.8 mL/min/1.73 m 2 at 24 months. These results suggest that, in patients with a solitary kidney, RPN is a safe and feasible treatment option. In patients with a solitary kidney, RPN did not significantly compromise renal function for up to 2 years after surgery.

Objective: To compare the perioperative and renal functional outcome between transperitoneal and retroperitoneal robotic partial nephrectomy (TP-RPN and RP-RPN) in the largest cohort to date of RP-RPN for posterior tumors., Methods: We identified 519 patients who met eligibility criteria and underwent TP-RPN (n = 357, 68.8%) or RP-RPN (n = 162, 31.2%) for a posteriorly located cT1 tumor. Patients were propensity score (PS) matched on preoperative and tumor-specific characteristics. Perioperative outcome and renal function outcome at median follow-up 22 months were compared., Results: Between the PS matched TP-RPN (n = 157, 50%) and RP-RPN (n = 157, 50%) patients, operative time (OT) (185.0 versus 157.0, P < .001) was longer in TP-RPN versus RP-RPN patients. No significant differences in ischemia time (P = .618), blood loss (P = .178), positive surgical margins (P = .501), overall postoperative complications (P = .861), or progression of chronic kidney disease stage at median 22 months (P = .599) were identified. Length of stay (LOS) was reduced in RP-RPN patients (P = .017), but was not different once an institution used a postoperative day (POD)-1 discharge protocol (P = .579). Operative times were similar between groups in patients with obesity (P = .293) or a cT1b renal mass (P = 908)., Conclusion: RP-RPN for posterior tumors resulted in reduced OT and a shorter LOS compared to TP-RPN. When surgeons aimed to routinely discharge patients on POD-1, the surgical approach did not influence LOS. Operative time was similar between RP and TP-RPN among patients with obesity or a cT1b renal mass. All other measures, including ischemia time, blood loss, margin rates, complications, and renal function, did not differ between the two approaches.

Background: Decreased functional outcome after partial nephrectomy is associated with overall mortality., Objective: To create a model that predicts ≥25% reduction from baseline estimated glomerular filtration rate (eGFR) in patients undergoing robot-assisted partial nephrectomy (RAPN) and to investigate the role of acute kidney injury (AKI) in this patient population., Design, Setting, and Participants: A total of 999 patients were identified from a multi-institutional database. Renal function was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines for chronic kidney disease (CKD). AKI was defined as >25% reduction in eGFR from pre-RAPN period to discharge., Outcome Measurements and Statistical Analysis: A nomogram to predict significant eGFR reduction (≥25% from baseline) in the time-frame between 3 and 15mo after RAPN was built based on the coefficients of Cox survival function that ultimately included age, sex, Charlson comorbidity index, baseline eGFR, RENAL nephrometry score, AKI in patients with normal baseline renal function, and AKI on CKD. Such landmark analysis was chosen in order to account for eGFR fluctuations occurring within the first 3mo of RAPN. The proportional hazard assumption was evaluated through the Schönfeld test. Internal validation was performed using the leave-one-out cross validation. Calibration was graphically investigated. The decision curve analysis (DCA) was used to evaluate the net clinical benefit., Results and Limitations: Median (interquartile range [IQR]) age at surgery was 61yr (51, 68). Overall, 146 patients experienced significant eGFR reduction; median follow-up for survivors was 12.4mo. The 15-mo probability of significant eGFR reduction was 19%. All variables fitted into the model, including AKI in patients with normal renal function (hazard ratio [HR]: 4.51; 95% confidence interval [CI]: 3.12, 6.60; p<0.001) and AKI on CKD (HR: 4.90; 95% CI: 2.17, 11.1; p<0.001), emerged as predictors of significant eGFR reduction (all p≤0.048) and were considered to build a nomogram. The internally validated c index was 73%. The model demonstrated excellent calibration and a net benefit at the DCA with probabilities ≥4%., Conclusions: We developed a nomogram that accurately predicts significant eGFR reduction after RAPN. This model may serve as a tool for early identification of patients at high risk for significant renal function decline after surgery., Patient Summary: We have developed a model for the prediction of renal function loss after partial nephrectomy for renal cancer., (Copyright © 2018 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Purpose: To evaluate and compare the accuracy of computed tomography (CT) and magnetic resonance imaging (MRI) in predicting the final pathologic tumor size of partial nephrectomy specimens., Materials and Methods: We analyzed a multi-institutional database of 807 patients who underwent robotic partial nephrectomy for a cT1a renal mass from 2006 to 2016. Patients who had a solitary tumor with complete data on the baseline imaging modality and the tumor size (baseline and pathologic) (n = 349) were included for analysis. Baseline tumor size evaluated by both imaging modalities, in addition to the difference between the measurements and final pathologic tumor size (cm) measurements, was compared between patients who received a baseline CT (n = 276, 79.1%) and those who received an MRI (n = 73, 20.9%)., Results: There were no statistically significant differences between any baseline characteristics and receipt of a CT versus MRI. In multivariable analysis adjusting for confounders, there was no significant difference in the baseline tumor size between patients receiving an MRI and those receiving a CT (2.3 versus 2.6 cm; β = -0.13; 95% confidence interval [CI] = -0.33 to 0.07; P = .208). Tumor size on imaging was smaller from final pathology by 0.43 cm on average (P = .002). Measurement error for the measured baseline versus actual pathologic tumor size did not significantly differ for patients receiving an MRI versus those receiving a CT (0.38 versus 0.44 cm; β = -0.06; 95% CI = -0.16 to 0.04; P = .232)., Conclusion: Baseline renal tumor size measurements were not significantly different for CT scan and MRI. Choice of imaging modality can be based on doctor and patient preference, including cost and exposure to radiation.

Objective: The majority of patients undergoing partial nephrectomy (PN) present with a clinical T1a tumor with both kidneys present. Some groups have advocated using off-clamp (Off-C) techniques to eliminate warm ischemia whenever possible, even when elective. We evaluated whether Off-C technique during robotic PN (RPN) provides any functional benefit over main arterial clamping (MAC) in these patients. Subjects/Patients and Methods: A total of 351 patients with a R.E.N.A.L. nephrometry score (RNS) <10, T1a tumor, and two kidneys who underwent RPN from five high-volume surgeons between 2008 and 2016 were retrospectively identified from a multi-institutional database. MAC and Off-C patients were 2 to 1 nearest neighbor propensity score matched on tumor size, RNS, % endophytic, tumor location, age, gender, body mass index, comorbidities, baseline estimated glomerular filtration rates (eGFRs), and surgeon performing the RPN. Preoperative, surgical, and postoperative outcomes were compared., Results: After propensity score matching, 82 MAC and 41 Off-C RPN patients were compared with no remaining statistically significant differences in baseline demographic or tumor-specific characteristics, including tumor size (p = 0.203) or RNS (p = 0.744). There were no significant differences in complications (p = 0.141), positive surgical margins (p = 0.625), or non-neoplastic parenchymal volume removed (p = 0.138). Off-C RPN had significantly higher estimated blood loss (100 mL vs 50 mL, p < 0.001), but no increased rate of transfusion (p = 0.328). There were no significant differences in rates of acute kidney injury (p = 0.132) nor percentage change in eGFRs (p = 0.763) at discharge. Freedom from progression of chronic kidney disease (CKD) stage was 87.7% for MAC and 91.1% for Off-C at 12 months. The percentage change in eGFRs (p = 0.457) and CKD stage progression (p = 0.866) was not different at last follow-up (median 9.2 months)., Conclusion: Our data showed that the use of Off-C RPN marginally increased blood loss without providing a renal function benefit. In two-kidney patients presenting with a T1a renal tumor, Off-C RPN may not be necessary.

Purpose: We evaluated the predictive value of the ACS NSQIP® (American College of Surgeons National Surgical Quality Improvement Program®) surgical risk calculator in a tertiary referral cohort of patients who underwent robot-assisted partial nephrectomy., Materials and Methods: We queried our prospectively maintained, multi-institutional database of patients treated with robot-assisted partial nephrectomy and input the preoperative details of 300 randomly selected patients into the calculator. Accuracy of the calculator was assessed by the ROC AUC and the Brier score., Results: The observed rate of any complication in our cohort was 14% while the mean predicted rate of any complication using the calculator was 5.42%. The observed rate of serious complications (Clavien score 3 or greater) was 3.67% compared to the predicted rate of 4.89%. Low AUC and high Brier score were calculated for any complication (0.51 and 0.1272) and serious complications (0.55 and 0.0352, respectively). The calculated AUC was low for all outcomes, including venous thromboembolism (0.67), surgical site infection (0.51) and pneumonia (0.44)., Conclusions: The ACS NSQIP risk calculator poorly predicted and discriminated which patients would experience complications after robot-assisted partial nephrectomy. These findings suggest the need for a more tailored outcome prediction model to better assist urologists risk stratify patients undergoing robot-assisted partial nephrectomy and counsel them on individual surgical risks., (Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Objectives: To evaluate trends in peri-operative outcomes of 250 consecutive cases beyond the initial learning curve (LC) of robot-assisted partial nephrectomy (RAPN) among multiple surgeons., Patients and Methods: A multi-institutional database was used to evaluate trends in patient demographics (e.g. age, gender, comorbidities), tumour characteristics (e.g. size, complexity) and peri-operative outcomes (e.g. warm ischaemia time [WIT], operating time, complications, estimated blood loss [EBL], trifecta achievement) in consecutive cases 50-300 (n = 960) from 2008 to 2016 among four experienced surgeons. Trends in outcomes were assessed using multivariable regression models adjusted for demographic and tumour-specific variables. Outcomes for cases 50-99 were compared with those for cases 250-300., Results: In the study period RAPN was increasingly performed in patients with larger tumours (β = 0.001, P = 0.048), hypertension (odds ratio [OR] 1.003; P = 0.008) diabetes (OR 1.003; P = 0.025) and previous abdominal surgery (OR 1.003; P = 0.006). Surgeon experience was associated with more trifecta achievement (OR 1.006; P < 0.001), shorter WIT (β = -0.036, P < 0.001), less EBL (β = -0.154, P = 0.009), fewer blood transfusions (OR 0.989, P = 0.024) and a reduced length of hospital stay (β = -0.002, P = 0.002), but not with operating time (P = 0.243), complications (P = 0.587) or surgical margin status (P = 0.102). Tumour size and WIT in cases 50-99 vs 250-300 were 2.7 vs 3.2 cm (P = 0.001) and 21.4 vs 16.2 min (P < 0.001), respectively., Conclusion: Refinement of RAPN outcomes, concomitant with the treatment of a patient population with larger tumours and more comorbidities, occurs after the initial LC is reached. Although RAPN can consistently be performed safely with acceptable outcomes after a small number of cases, improvement in trifecta achievement, WIT, EBL, blood transfusions and a shorter hospitalization continues to occur up to 300 procedures., (© 2016 The Authors BJU International © 2016 BJU International Published by John Wiley & Sons Ltd.)

Introduction: Previous robot-assisted partial nephrectomy (RAPN) studies have identified various predictors of overall and major postoperative complications, but few have evaluated the specific role of these factors in the development of medical and surgical complications. In this study, we present an analysis of the modifiable and nonmodifiable variables influencing medical and surgical complications in a contemporary series of patients who underwent RAPN and were followed in a prospectively maintained, multi-institutional kidney cancer database., Methods: A retrospective review of all patients who underwent RAPN at four institutions between 2008 and 2015 was performed. Multivariable logistic regression models were used to determine predictors of medical and surgical postoperative complications., Results: Data from 1139 patients were available for analysis. Sixty-seven patients (5.8%) experienced a medical postoperative complication, and 82 (7.1%) experienced a surgical complication. Decreasing baseline estimated glomerular filtration rate (eGFR) (odds ratio [OR] = 0.98, p = 0.003), greater estimated blood loss (EBL) (OR = 1.002, p = 0.001), and operating surgeon (OR = 8.01, p < 0.001) were associated with an increased likelihood of surgical complications, while decreasing baseline eGFR (OR = 0.99, p = 0.054) and operating surgeon (OR = 1.96, p = 0.054) were associated with an increased likelihood of medical complications., Conclusion: We present complication risks in a large contemporary cohort of patients undergoing robotic partial nephrectomy (RPN) with only 11.3% of patients experiencing a medical or surgical postoperative complication. Prospective candidates for robotic PN with poor baseline renal function and/or risk factors for greater EBL, including a high body mass index, or a complex renal mass should be counseled appropriately on their increased risk for a medical or surgical postoperative complication.

Objectives: To assess the benefit of selective arterial clamping (SAC) as an alternative to main renal artery clamping (MAC) during robot-assisted partial nephrectomy (RAPN) in patients without underlying chronic kidney disease (CKD)., Patients and Methods: Our study cohort comprised 665 patients without impaired renal function undergoing MAC (n = 589) or SAC (n = 76) during RAPN from four medical institutions in the period 2008-2015. We compared complication rates, positive surgical margin (PSM) rates, and peri-operative and intermediate-term renal functional outcome between 132 patients undergoing MAC and 66 undergoing SAC after 2-to-1 nearest-neighbour propensity-score matching for age, sex, body mass index, RENAL nephrometry score, tumour size, baseline estimated glomerular filtration rate (eGFR), American Society of Anesthesiologists (ASA) score, Charlson comorbidity index (CCI) and warm ischaemia time (WIT)., Results: In propensity-score-matched patients, PSM (5.7 vs 3.0%; P = 0.407) and complication rates (13.8 vs 10.6%; P = 0.727) did not differ between the MAC and SAC groups. The incidence of acute kidney injury for MAC vs SAC (25.0 vs 32.0%; P = 0.315) within the first 30 days was similar. At a median follow-up of 7.5 months, the percentage reduction in eGFR (-9.3 vs -10.4%; P = 0.518) and progression to CKD ≥ stage 3 (7.2 vs 8.5%; P = 0.792) showed no difference., Conclusions: Our study findings show no difference in PSM rates, complication rates or intermediate-term renal functional outcomes between patients with unimpaired renal function who underwent SAC vs those who underwent MAC. When expected WIT is low, the routine use of SAC may not be necessary. Further studies will need to determine the role of SAC in patients with a solitary kidney or with significantly impaired renal function., (© 2016 The Authors BJU International © 2016 BJU International Published by John Wiley & Sons Ltd.)

Objective: To compare renal function outcome between a contemporary cohort of propensity score-matched patients undergoing main renal artery clamping (MAC) alone and those undergoing main renal artery clamping with renal vein clamping (MVAC) during robotic partial nephrectomy., Materials and Methods: Patients with a solitary T1 renal mass undergoing robotic partial nephrectomy were propensity score-matched on American Society of Anesthesiologists score, RENAL Nephrometry score, tumor size, tumor laterality, and operating surgeon to provide 66 patients undergoing MAC and 66 patients undergoing MVAC for analysis. Demographic and tumor-specific characteristics in addition to perioperative and renal function outcomes at discharge and 9 months were compared., Results: No differences in any baseline characteristics including age (P = .847), baseline estimated glomerular filtration rate (eGFR) (P = .358), RENAL Nephrometry score (P = .617), and tumor size (P = .551) were identified. Warm ischemia time was longer in patients undergoing MVAC than in patients undergoing MAC (21.0 minutes vs 15.0, P <.001), with no differences in estimated blood loss (P = .413), length of hospitalization (P = .112), and postoperative complications (overall [P = .251], by Clavien-Dindo classification [P = .119]). No differences in the percent change in eGFR (P = .866) or acute kidney injury (P = .493) at discharge and no differences in the percent change in eGFR (P = .401) or progression to chronic kidney disease (P = .594) at 9 months were identified., Conclusion: Compared with MAC, clamping of the renal vein in addition to the main renal artery does not appear to adversely affect postoperative renal function. Future studies comparing MAC with MVAC partial nephrectomy in patients with baseline chronic kidney disease, a solitary kidney and complex tumors with prolonged warm ischemia time are necessary., (Copyright © 2016 Elsevier Inc. All rights reserved.)