Single High-volume Center Research Articles

A0126 - Does the surgical technique impact the oncologic outcomes after partial nephrectomy? A comparison between open, laparoscopic and robotic approach in a single high-volume tertiary center

A0126 - Does the surgical technique impact the oncologic outcomes after partial nephrectomy? A comparison between open, laparoscopic and robotic approach in a single high-volume tertiary center

A0631 - Clinical and surgical predictors of urinary tract endometriosis after primary surgical treatment: A single high-volume centre experience

A0631 - Clinical and surgical predictors of urinary tract endometriosis after primary surgical treatment: A single high-volume centre experience

A0065 - Prognostic features of Upstaged pT3a Renal Cell tumors with fat invasion: A single high-volume centre experience

A0065 - Prognostic features of Upstaged pT3a Renal Cell tumors with fat invasion: A single high-volume centre experience

Postoperative CRP Levels Can Rule out Anastomotic Leaks in Crohn's Disease Patients.

Background: In colorectal cancer, C-reactive protein (CRP) levels on postoperative days 3–4 have a strong negative predictive value for an anastomotic leak, with threshold values of ~15 on post-operative day (POD) 3 and ~13 on POD 4. In Crohn’s disease, CRP levels are perceived as unreliable in the postoperative period because of the underlying inflammatory process. The aim of this study was to determine whether postoperative CRP levels can be used to rule out anastomotic leaks in patients with Crohn’s disease and to set CRP threshold values for this population. Methods: This was a retrospective study of a population of Crohn’s disease patients who underwent surgery with bowel anastomoses at a single high-volume center between 1/2012 and 12/2017. The operations were performed by a single colorectal consultant who is an inflammatory bowel disease specialist. Results: Ninety-two operations were performed. A CRP level of 19.56 mg/dL on postoperative day 3 had an area under the curve of 0.865 (sensitivity 88%, specificity 73%) and a negative predictive value (NPV) of 98% for an anastomotic leak. Patients with an anastomotic leak showed a trend towards decreased postoperative albumin levels (p = 0.06). Conclusions: Mean CRP levels and CRP threshold values were indeed higher in the study population compared with those in colorectal cancer patients. Threshold values were set at 20.3 mg/dL on POD 3, 19.5 mg/dL on POD 4 and 16.7 mg/dL on POD 5. These values had high NPVs and can be used to rule out anastomotic leaks in patients with Crohn’s disease after surgery with bowel anastomosis.

Failure to Rescue as Indicator of Quality of Care. Analysis of 3003 Liver Resections at a Single High-Volume Hepatobiliary Surgery Unit over Three Decades

Introduction: Failure to rescue (FTR), defined as the probability of postoperative death among patients with major complication, has been proposed to assess quality of care during hospitalization. Aim of this study was to evaluate the improvement of safety of liver resections (LR) at a single high-volume center over 30 years.

Single-Center Experience of 500+ Minimally Invasive Pancreatic and Liver Resections: Insights into Implementing a MIS-HPB Practice

Background: Minimally invasive, robotic and laparoscopic, HPB surgery (MIS-HPB) is increasingly being implemented. This study aimed to provide insights into implementation and outcome of MIS-HPB in a single high-volume center.

In vitro fertilization as an independent risk factor for perinatal complications: Single-center 10 years cohort study.

Assisted Reproductive Technology (ART) has made great strides in the past forty-years, but no medical treatment comes without side effects. Despite several studies reporting high incidences of perinatal complications, the association is inconclusive. Also, the effect of racially and ethnically distinguished Asian population undergoing ART on perinatal outcomes is not well studied. Therefore, this study attempts to compare various perinatal outcome parameters in ART, and spontaneously conceived singleton pregnancies from a single high-volume tertiary care center. This is a retrospective cohort study from a single tertiary infertility center, carried out from January 2011 to September 2020. The study included 1,125 IVF conceived babies (AB group) and 7,193 spontaneous conceived babies (SB group). The groups were compared using the Pearson Chi-square test and adjusted odds ratio, calculated using the multivariate analysis. Most of the perinatal complications, such as preterm birth (PTB), early preterm birth, low birth weight (LBW), extremely low birth weight, small for gestational age, large for gestational age babies, neonatal intensive care unit (NICU) admission, need for surfactant, meconium aspiration syndrome, neonatal seizures, intraventricular hemorrhage, hypoxic-ischemic encephalopathy, and patent ductus arteriosus was significantly increased in the AB group when compared to the SB group (p<0.05). In-vitro fertilization (IVF) independently increases the risk of LBW (aOR 2.530; 95% CI 2.194-2.917), PTB (aOR 4.004; 95% CI 3.496-4.587), NICU admission (aOR 2.003; 95% CI 1.610-2.492) and neonatal seizures (aOR 9.805; 95% CI 5.755-16.706).Conclusions: All ART-conceived pregnant patients should receive antenatal counselling regarding perinatal complications and should deliver at a tertiary care center with appropriate NICU support.

Surgical Outcomes of Ampullary and Non-ampullary Adenocarcinoma of the Duodenum: A Single Institutional Study of a Tertiary Cancer Center

Introduction: Among periampullary tumors, there are two adenocarcinomas (ACs) of duodenum arising from ampulla of Vater (AoV) and non-ampullary duodenal mucosa. These have lower incidence compared to other periampullary tumors. The purpose of this retrospective study was to evaluate these duodenal ACs that pancreaticoduodenectomy (PD) was performed in a single high-volume tertiary cancer center.

The role of cardiac surgery in transvenous lead extraction. A high-volume center experience with 3207 procedures.

IntroductionThe guidelines stress the importance of cardiac surgery in the management of life-threatening complications arising from lead removal.AimTo delineate the roles of the cardiac surgeon during transvenous lead extraction (TLE).Material and methods3207 patients (38.7% F), average age 65.7 years, underwent the extraction of PM/ICD leads using standard non-powered mechanical systems within the last 14 years.ResultsProcedural success 96.1%, clinical success 97.8%, procedure-related death 0.18%, major complications 1.9% (cardiac tamponade 1.2%, hemothorax 0.2%, tricuspid valve damage 0.3%, stroke and pulmonary embolism < 1%). The roles for cardiac surgery in TLE have been categorized into five areas: 1. Emergency cardiac surgery (1.18% of all patients), 2. Late surgical intervention (TLE-related tricuspid valve dysfunction) (0.44%), 3. Cardiac surgery complementing partially successful TLE (0.68%: removal of lead fragments), 4. Epicardial pacemaker implantation through sternotomy for the above-mentioned reasons (0.65%), 5. Delayed surgical intervention after TLE to place epicardial LV leads (0.53%). Additionally, surgical experience can help in prevention and treatment of wound infection after TLE.ConclusionsEmergency cardiac surgery (mainly due to severe bleeding) is still the most frequent reason for intervention (33.63% (38/113) of all surgical procedures). The other areas of surgical interventions in lead management are: cardiac surgery complementing partially successful TLE, repair or replacement of the malfunctioning tricuspid valve secondary to lead extraction and implantation of permanent epicardial pacing leads after sternotomy or epicardial left ventricle lead to optimize cardiac resynchronization. Experience of a single high-volume lead extraction center confirms the need for close collaboration between the cardiologist and the cardiac surgeon, whose role goes far beyond mere surgical standby.

Neutrophil-Lymphocyte Ratio Fails to Predict Survival after Pancreatectomy for Pancreatic Ductal Adenocarcinoma

Introduction: The aim of this study was to analyze the role of neutrophil-lymphocyte ratio (NLR) and its variation (delta NLR), lymph node ratio (LNR) and perineural invasion in overall survival (OS) after pancreatectomy for pancreatic ductal adenocarcinoma (PDAC) at a single academic high-volume center.

P-OGC19 The predictive role of cardiopulmonary exercise testing in gastric cancer surgery

Abstract Background The role of Cardiopulmonary Exercise Testing (CPET) prior to major surgery has been an area of growing interest over the last two decades. CPET offers an objective and composite measure of physiological functional reserve, and thus can be used to identify patients at highest risk of peri-operative morbidity and mortality. Although the role of CPET has been investigated with respect to outcomes after oesophagectomy, no clear data exist into the predictive role of CPET specifically relating to gastric cancer surgery. The aim of this study was to identify CPET parameters predictive of adverse outcome in patients undergoing curative gastric resections. Methods Patients who underwent CPET followed by curative total or subtotal gastrectomy for gastric or junctional adenocarcinoma between January 2013 and December 2019 in a single high-volume centre were included in retrospective analysis. CPET variables were categorised as per cut-off values from other surgical populations (AT &amp;lt; 11ml.min-1.kg-1, VO2peak&amp;lt;15ml.min-1.kg-1, VE/VCO2 at AT &amp;gt; 34). Associations between these variables and postoperative outcomes were analysed using chi squared or Fisher’s exact test. Results There were 252 patients included in the study. Patients with VE/VCO2&amp;gt;34 were more likely to return to the intensive care unit (ICU) (p = 0.033) and had a higher chance of in-hospital mortality (p = 0.012). AT &amp;lt; 11ml.min-1.kg-1 or VO2peak&amp;lt;15ml.min-1.kg-1 were not associated either with return to ICU (p = 0.243, p = 0.202) or with in-hospital mortality (p = 1.000, p = 1.000). Conclusions Although much has been published on the importance of CPET assessment prior to major abdominal surgery, there is a paucity of literature specifically looking at its role in patients with gastric cancer. Patients with ventilatory inefficiency (VE/VCO2&amp;gt;34) are more likely to return to ICU or to die during hospital stay after total/subtotal gastrectomy for malignant disease. This information should play a more prominent role when assessing patients’ fitness prior to surgery.

P-OGC60 Predicting the risk of venous thromboembolism during neoadjuvant therapy for oesophagogastric cancer

Abstract Background Locally advanced oesophageal cancer is usually treated with neoadjuvant treatment (NAT) followed by surgery. Venous thromboembolism (VTE) is a recognised complication in these patients. Those who develop VTE may have an inferior vena cava filter placed prior to surgery to reduce the risk of further complications. This study aimed to identify specific risks for VTE during (NAT) for oesophagogastric cancer (OGC) and whether this increases postoperative morbidity. Methods Patients undergoing NAT for OGC followed by surgery at a single high-volume centre between January 2015 and June 2020 were identified from a prospectively maintained database. Univariable and multivariable logistic regression analyses were performed to identify independent risk factors for the development of VTE as well as the association between diagnosis of VTE and morbidity. Results The incidence of VTE in this cohort was 6.7% (27/406). Independent risk factors for developing VTE in multivariable analysis were BMI – OR 1.093 (p = 0.045) and age – OR 1.067 (p = 0.019). Type of chemo(radio)therapy regimen used, pT, pN stage, previous history of ischaemic heart disease or being an active smoker at diagnosis was not associated with VTE occurrence. Diagnosis of VTE during neoadjuvant treatment was not associated with a higher risk of developing a serious postoperative complication (Clavien-Dindo grade III and above) (p = 0.699). Conclusions Patients with a raised BMI or older age are at higher risk of developing VTE during NAT for OGC. These patients must be appropriately counseled on the higher risk of VTE prior to commencing NAT. However, the development of a VTE does not appear to confer any additional post-operative complication risk.

P-OGC18 Does cardiopulmonary testing help predict long-term survival after oesophagectomy?

Abstract Background Oesophagectomy is associated with a high rate of morbidity and mortality. Preoperative cardiopulmonary fitness has been correlated with outcomes within major surgery. Variables derived from CPET have been associated with postoperative outcomes. It is unclear whether preoperative cardiorespiratory fitness of patients undergoing oesophagectomy is associated with long-term survival. The aim of this study was to evaluate whether any of the cardiopulmonary exercise testing (CPET) variables that are routinely derived in patients with oesophageal cancer may aid in predicting long-term survival after oesophagectomy. Methods Patients undergoing CPET followed by trans-thoracic oesophagectomy for oesophageal cancer with curative intent between January 2013 and January 2017 from single high-volume centre were retrospectively analysed. The relationship between predictive co-variables including CPET variables, and survival was studied with a Cox proportional hazard model. Receiver operation curve (ROC) analysis was conducted to find cut-off values for CPET variables predictive of 3-year survival. Results A total of 313 patients were analyzed. The ventilatory equivalent for carbon dioxide (VE/VCO2) at anaerobic threshold was the only CPET variable independently predictive of long-term survival in multivariable analysis (HR 1.049, 95% CI 1.011-1.088, p = 0.011). Pathological stage III and IV disease was the other co-variable found to be independently predictive of survival. ROC analysis of the VE/VCO2 failed to demonstrate a predictive cut-off value of 3-year survival (AUC=0.564, 95% CI 0.499-0.629, p = 0.056). Conclusions A high VE/VCO2 before oesophagectomy for malignant disease is an independent predictor of long-term survival and may be an important variable for consideration when counselling patients.

Inguinal lymph node density as a powerful predictor of cancer specific survival in patients with node-positive penile cancer.

Penile cancer (PC) is an aggressive malignancy in which the most important prognostic factor for cancer specific survival (CSS) is the involvement of regional lymph nodes (LNs). Lymph node density (LND) could become a superior prognostic tool for CSS, by accounting for both extent of dissection and nodal disease burden. We aim to validate LND as a prognostic factor for CSS in a contemporary series of patients with PC treated and followed at a single high-volume center, treating more than 25 PC patients per year, over a 13-year period. Clinical charts of all patients with PC who underwent surgical treatment between 2007 and 2020 were reviewed. Clinicopathological data was collected and analyzed retrospectively. We only included patients with ≥ 8 LNs removed in a unilateral ILND or ≥16 LNs when a bilateral approach was used. We attempted to find an optimal threshold for LND, capable of maximizing effect difference in terms of CSS and RFS between dichotomized groups. To determine this threshold, we used the chi-squared and the Mann-Whitney tests, and it was required to fulfill the proportional hazards assumption. We assessed different thresholds previously reported in the literature. In our study the optimal threshold for LND was determined to be ≤ 20% Descriptive statistics were used to summarize patient characteristics, CSS and RFS were graphically represented by Kaplan-Meier estimates. Harrell's C index for CSS and RFS were calculated for LND and pN stage, to determine which variable has a superior predictive capacity RESULTS: We identified 110 patients with PC who underwent ILND at our institution, of these, 87 were node-positive and were included in the final analysis. Overall estimates of CSS showed a 3-year CSS of 43% (95% CI: 32-54), the estimated 3-year CSS for the patients with a LND ≤ 20% was 69% (95% CI: 50-82) and 26% (95% CI: 14-39) in the group with a LND >20% (Log-rank P = 0.001). The estimated 3-year RFS for the patients with LND ≤ 20% was 61% (95% CI: 42-76) and 30% (95% CI: 16-44) in the group with a LND >20% (Log-rank P = 0.009). The results of univariate analysis indicate that in patients with a LND >20% the risk for cancer specific mortality was increased (HR 2.68; 95% CI: 1.45-4.98, P = 0.002) compared with LND ≤ 20%. In the and Cox multivariate analysis after Adjusting for age and pN stage the association increased (HR 2.73; 95%, CI 1.38-5.40, P = 0.004). Harrell´s C index for CSS was 0.63 for LND vs. 0.54 for pN stage, suggesting a 9% higher concordance for LND and CSS. Lymph node density stands as a promising tool for risk-stratifying patients with node-positive PC after ILND. In this retrospective study, LND was a significant predictor of CSS and RFS when using a LND >20% threshold, and also showed a superior predictive ability than pN stage. These results support the use of the LND parameter in clinical practice with a final goal to improve risk stratification, and individualized adjuvant treatment decision-making to patients with high-risk of cancer specific mortality.

External validation of the Palacios' equation: a simple and accurate tool to estimate the new baseline renal function after renal cancer surgery.

To externally validate the Palacios' equation estimating the new baseline glomerular filtration rate (NB-GFR) after partial or radical-nephrectomy (PN, RN) for Renal cancer carcinoma (RCC). Our research group recently published two studies that investigated the association between renal function and cancer-specific survival in RCC. The first one included 3457 patients undergone RN or PN for a cT1-2 RCC coming from five high-volume centers; the second one considered 1767 patients undergone RN or PN for a cT1-4 RCC in a single high-volume center. From such datasets, available complete patients' data were used to calculate the predicted NB-GFR through the Palacios' equation: predicted NB-GFR = 35.03 + 0.65 ∙ preoperative GFR - 18.19 ∙ (if radical nephrectomy) - 0.25 ∙ age + 2.83 ∙ (if tumor size > 7cm) - 2.09 ∙ (if diabetes). The observed NB-GFR was calculated by the CKD-EPI equation on serum creatinine at 3-12months after surgery. Concordance between observed and predicted NB-GFR was evaluated by Lin's concordance correlation coefficient and Bland-Altman analysis. 2419 patients were included (1210, cohort #1; 1219, cohort #2). The median observed NB-GFR value in cohorts #1 and #2 was 73.0ml/min/1.73 m2 (IQR 56.1-90.1) and 64.2ml/min/1.73 m2 (IQR 49.6-83); the median predicted NB-GFR was 71.1ml/min/1.73 m2 (IQR 58-81.5) and 62.6ml/min/1.73m2 (IQR 47.9-75.9). The concordance line showed a slope of 0.80 and 0.86, and an intercept at 11.02 and 5.41ml/min/1.73 m2 in the cohort#1 and #2, respectively. The Palacio's equation moderately over-estimated and under-estimated NB-GFR, for values below and above the cut-off of 50ml/min/1.73 m2 and 35ml/min/1.73m2 in cohort#1 and #2. The Lin's concordance correlation coefficient was 0.79 (95% CI 0.77-0.81) and 0.83 (95% CI 0.82-0.85). We confirm the predictive performances of Palacios' equation, supporting its utilization in clinical practice.

Incidence and predictors of blood transfusions in one-stage bilateral total hip arthroplasty: a single center prospective cohort study.

The safety of performing one-stage bilateral total hip arthroplasty (THA) remains controversial among the orthopedic community. The aim of the present study was to determine the incidence and predictors of blood transfusions in one-stage bilateral THA performed in a high-volume single center. Patients undergoing one-stage bilateral THA between 2015 and 2017 were included. The following data were collected from the hospital medical records: age, body mass index (BMI), American Society of Anaesthesiologists (ASA) score, smoking habit, comorbidities, preoperative serum creatinine, serum iron, ferritin, C-reactive protein (CRP), and hemoglobin (Hb). The Hb levels at postoperative day 1 and 3 were also collected. A total of 367 patients with a mean age of 56.1years (range, 32-79) were included. Forty-eight (13%) patients were transfused with a mean number of 1.6 blood units per patient. In non-transfused patients, the average Hb drop was 3.6 (SD ± 1) g/dL and 4.9g/dL (SD ± 1.3) at postoperative day 1 and day 3, respectively. The average preoperative Hb level was 14.64 (SD ± 1.21) g/dL. In the univariate logistic regression, the following variables were predictive factors for transfusions: male gender (OR 0.447; P = 0.01), preoperative hemoglobin level (OR 0.622; P = 0.001), preoperative ferritin level (OR 0.995; P = 0.016), BMI (OR 0.837; P = 0.001), cardiopathy (OR 3.534; P = 0.046), preoperative anaemia (OR 10.54; P = 0.011). In the multivariate logistic regression only preoperative hemoglobin level (OR 0.666; P = 0.01), and BMI (OR 0.868; P = 0.007) were statistically significant. The incidence of blood transfusions after one-stage bilateral THA is low in non-anemic patients operated on at a high-volume arthroplasty center. The main predictors of blood transfusions are preoperative Hb level and BMI.

The optimized clinical workflow for pulmonary vein isolation with the radiofrequency balloon.

Pulmonary vein isolation (PVI) with radiofrequency (RF) catheter ablation is an effective treatment option for patients with paroxysmal AF. However, traditional point by point RF ablation can be time consuming and technically challenging. To simplify the ablation procedure, without compromising procedure outcome, several "single shot" ablation systems have been developed. The multi-electrode RF Balloon catheter HELIOSTAR is a 28-mm compliant balloon compatible with the CARTO 3D electroanatomical mapping system; an optimized step-by-step workflow to perform PVI is described. Procedures are performed under general anesthesia with unique transseptal puncture. To evaluate the optimal electrode-tissue contact and best RF Balloon positioning, the following baseline indicators should be fulfilled: inflation index > 0.8, impedance range close to 100 Ohms with a variability of less than 20 Ohms across electrodes, temperature variability on all electrodes < 3°C with a maximum temperature of 31°C. RF delivery along the posterior wall is programmed to 20s or shorter in case of esophageal temperature rise (> 2°C compared to baseline) and 60s for all the other segments. Target parameters for PVI are 1) time to isolation less than 12s; 2) impedance drop > 12 Ohms; 3) temperature rise > 6°C. Standardized workflow for RF Balloon is mandatory to achieve efficacy and safety with this new promising technology. In the absence of international guidelines, a single high-volume center procedural strategy is described for PVI.

Abstract 12804: Knowledge of Cardiovascular Disease Risk in Young Women of Reproductive Age: A Cross-Sectional Survey-Based Study

Introduction: Knowledge of cardiovascular disease (CVD) as the leading cause of death (LCOD) among women in the United States is declining. Young women who experience an adverse pregnancy outcome (APO) are at increased risk for CVD, but knowledge of CVD risk has not been well characterized in this population in the perinatal period. Our objective was to examine knowledge of CVD risk in postpartum women and to determine whether risk perception differs based on experience of APO. Methods: A cross-sectional study was conducted among postpartum individuals who had a live birth at a single high-volume quaternary care center between 1/1/20 and 7/1/20. Knowledge of CVD risk was assessed through a self-administered online survey adapted from the American Heart Association Survey of Women’s CVD Awareness. Survey data were collected between 3/1/21 and 4/18/21. We examined differences in knowledge of CVD risk factors based upon self-reported APO status. Results: Of the 5,612 eligible individuals contacted, 13% completed the survey. Among respondents, the majority identified as White (70%) with a mean age of 34 + 4.2 years, and 25% reported an APO. Similar proportions of women with (62%) and without (62%) an APO identified CVD as the LCOD in women. There was no significant difference in knowledge of traditional or pregnancy-specific CVD risk factors by APO status ( TABLE ). Women who experienced an APO were more likely to report intention to contact a healthcare professional regarding personal CVD risk compared with women who did not. Conclusions: Gaps remain in knowledge of CVD risk factors among young women, in whom primary prevention of CVD may be most beneficial over the lifespan. Heterogeneity in knowledge deficits related to APO subtypes as CVD risk factors present a unique opportunity for targeted education at a time when healthcare engagement is high. Given the modest response rate to this survey, awareness may be even lower in the general population.

Non-Standard Management of Target Vessels With the Inner Branch Arch Endograft: A Single-Center Retrospective Study

Purpose: The purpose of this study was to evaluate early and mid-term results of non-standard management of the supraaortic target vessels with the use of the inner branch arch endograft in a single high-volume center. Material and methods: A single-center retrospective study including all patients undergoing implantation of an inner branch arch endograft from December 2012 to March 2021, who presented a non-standard management of the supraaortic target vessels (any bypass other than a left carotid-subclavian or landing in a dissected target vessel). Technical success, mortality, reinterventions, endoleak (EL), and aortic remodeling at follow-up were analyzed. Results: Twenty-four patients were included. In 17 (71%) cases, the non-standard management was related to innominate artery (IA) compromise (12 with IA dissection, 2 with short IA, 2 with short proximal aortic landing zone that required occlusion of IA, 1 with occluded IA after open arch repair). Two (8%) cases were related to an aberrant right subclavian artery (RSA), 1 patient (4%) due to the concomitant presence of a left vertebral artery (LVA) arising from the arch and an occluded left subclavian artery (LSA), and another patient presented with an occluded LSA distal to a dominant vertebral artery. Three (13%) cases were exclusively related to management in patients with genetic aortic syndromes. Twenty (83%) patients had a previous type A aortic dissection. Ten (42%) patients presented a thoracic or thoracoabdominal aortic aneurysm and 8 (33%) patients an arch aneurysm, 6 of them associated to false lumen (FL) perfusion. There were 2 (8%) perioperative minor strokes, and 1 patient with perioperative mortality. Seven patients presented an early type I endoleak, all resolved at follow-up. Seven patients required reinterventions during follow-up (7 reinterventions related to continuous false lumen perfusion, 3 related to Type Ia endoleak, 2 related to surgical bypass). All patients who presented with FL perfusion had complete FL thrombosis at follow-up. No patient presented aneurysm growth at follow-up. Conclusions: The use of the inner branch arch endograft with a non-standard management of the supraaortic target vessels is a possible option. Despite a high reintervention rate, regression or stability of the aneurysmal diameter was achieved in all the patients with follow-up.

PE35 - Does the surgical technique impact the oncologic outcomes after partial nephrectomy? A comparison between open, laparoscopic and robotic approach in a single high-volume tertiary center

PE35 - Does the surgical technique impact the oncologic outcomes after partial nephrectomy? A comparison between open, laparoscopic and robotic approach in a single high-volume tertiary center