Higher RENAL Nephrometry Score is predictive of longer warm ischemia time and collecting system entry during laparoscopic and robotic-assisted partial nephrectomy

Best predictive single nephrometry score component to correlate with achievement of trifecta outcome in laparoscopic and robotic surgery

BACKGROUND

To evaluate the predictive value of individual components of the R.E.N.A.L scoring system for Laparoscopic (LPN) and Robotic Partial Nephrectomy (RPN).

METHODS

Patients that had undergone a Laparoscopic (LPN) or Robotic Partial Nephrectomy (RPN) between 2018 and 2023 were reviewed. Our data collection included Race, Ethnicity, Age, BMI, R.E.N.A.L nephrometry score, and complications. Cases that achieved trifecta outcomes were designated as "Group A" and cases that did not achieve trifecta were "Group B". All the data were collected using REDCap database.

RESULTS

A total of 111 cases were included, Group A consisted of 82% of all cases, whereas Group B 18%. Radius score demonstrated significant distinction concerning trifecta attainment and was the most predictive component of the 5 scoring metrics of the nephrometry system. In a subgroup analysis, R-score of 3 or a renal mass measuring ≥ 7 cm, was a significant independent negative predictor for trifecta outcomes, as well as tumor size at presentation.

CONCLUSION

Renal nephrometry score is predictive of trifecta outcomes for patients undergoing laparoscopic or robotic partial nephrectomy. Radius of mass was the most effective predictive component of the nephrometry score for trifecta prediction.

Associations between R.E.N.A.L. nephrometry score and survival outcomes in renal tumours

OBJECTIVE

The radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry score could be used to predict surgical outcomes and renal tumour aggressiveness. We aimed to analyse its associations with survival outcomes.

METHODS

We included 1368 patients with sporadic, unilateral and non-metastatic renal tumours who received curative nephrectomy in Zhongshan Hospital from January 2009 to September 2019. Radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry scores were assigned by three urologists based on preoperative CT/MRI scans. Correlations between parameters or sum of radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry scores, overall survival and recurrence-free survival were analysed by Kaplan-Meier analyses and the multivariate Cox regression model. We further compared survival outcomes between patients who received partial nephrectomy and patients who received radical nephrectomy.

RESULTS

We observed statistically significant associations between all components of radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry scores and oncologic outcomes, including R (radius) (overall survival, P < 0.001; recurrence-free survival , P < 0.001), E (exophytic/endophytic) (overall survival, P = 0.003; recurrence-free survival, P < 0.001), N (nearness) (overall survival, P = 0.063; recurrence-free survival, P < 0.001), A (anterior/posterior) (overall survival, P < 0.001; recurrence-free survival, P = 0.005), L (location) (overall survival, P = 0.008; recurrence-free survival, P < 0.001) and suffix 'h' (overall survival, P = 0.237; recurrence-free survival, P = 0.034). Kaplan-Meier curves of overall survival and recurrence-free survival rates were significantly different when stratified by radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry score complexity group (overall survival, P < 0.001; recurrence-free survival, P < 0.001). After adjusting for tumour stage and grade, radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry score as continuous variables was an adverse independent risk factor for survival outcomes [P = 0.027, hazard ratio (95% confidence interval) = 1.151 (1.016-1.303)] and recurrence-free survival [P < 0.001, hazard ratio (95% confidence interval) = 1.299 (1.125-1.501)]. For tumours with radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry scores of 4 and 5, partial nephrectomy showed a survival benefit than radical nephrectomy.

CONCLUSION

Both components and complexity groups of the radius-exophytic/endophytic-nearness-anterior/posterior-location nephrometry score are associated with survival outcomes in renal tumour patients.

Factors influencing the decision-making in laparoscopic partial nephrectomy for small renal masses

BACKGROUND AND OBJECTIVES

We analyzed the factors affecting the decision on surgical approach such as hilum dissection, vessel clamping, and the warm ischemia time (WIT) in laparoscopic partial nephrectomy (LPN) for small renal masses (SRMs).

METHODS

Patients who underwent LPN for SRMs between 2011 and 2021 in two centers were retrospectively screened. Standardized R.E.N.A.L. nephrometry score (RNS) and each of the components were scored on a Likert scale and the effect on the surgical approach was examined by using them separately.

RESULTS

A total of 133 patients, 85 of whom were on-clamp and 48 were off-clamp, were included in the study. Greater tumor size, low BMI, higher RNS, upper pole tumor, low exophytic rate, and nearness to the collecting system were statistically significant for both on/off-clamp and hilar dissection decisions. In multivariate analysis, greater tumor size, upper pole tumor, lower rate of exophytic part (E2), nearness to the collecting system (N3) were independent risk factors for vessel clamping. Greater tumor size and lower exophytic tumor rate (E2) were independent risk factors for hilum dissection. We could not identify any factor affecting WIT.

CONCLUSION

Individual components of RNS may serve as a better tool for decision-making on vessel clamping and hilum dissection during LPN for SRMs.

A Novel Technique of Renorrhaphy in Difficult Partial Nephrectomies by Single-Layered Parenchymal Imbrication

Background In partial nephrectomies, achieving the trifecta outcome of negative tumor margins, no surgical complications, and minimal decline in renal function depends on various factors, with the complexity of the tumor described by the nephrometry score being chief among them. These factors often motivate surgeons toward a minimally invasive route even if the preferred route is an open approach. We describe an innovative renorrhaphy technique that overcomes the commonly encountered difficulty in reconstructing the renal parenchyma after resecting a complex tumor with a single-layered parenchymal imbrication (SLPI) technique. Methodology We conducted a retrospective review of case records of the patients who had undergone partial nephrectomies in our center from March 2017 to March 2021. The patients who underwent the SLPI technique were chosen, and data were extracted. Data collected included patients' preoperative imaging findings; intraoperative parameters such as ischemia time, blood loss, and number of renal arteries; and postoperative factors such as margin positivity rate, urine leak, secondary bleeding, follow-up imaging, and recurrence rates. Results A total of 28 patients were included in our study. The estimated blood loss was 234 mL (standard deviation [SD] = 55 mL), warm ischemia time was 31 minutes (SD 4 minutes), a hospital stay of 3 days (SD 2 days), two minor complications, two intraoperative complications, and one margin positivity. There were no major complications or recurrences. Conclusions The novel technique of SLPI renorrhaphy can help deal with complex renal masses and is an easily reproducible technique both in open and minimally invasive approaches.

Comparative Analysis of Trifecta Outcomes in Robot-Assisted Partial Nephrectomy for cT1a Versus cT1b + Renal Tumours-a Single-Centre Study

Robotic assistance is being increasingly utilised for nephron-sparing surgery for complex renal masses. We evaluated the outcomes of robot-assisted partial nephrectomy (RAPN) for cT1a versus cT1b + renal masses by a comparative analysis of trifecta outcomes between these two groups of patients. We utilised our prospectively maintained database to identify patients undergoing RAPN for cT1a (group 1, n = 41) and cT1b + (group 2, n = 37) renal masses from April 2016 to March 2020. The oncological and trifecta outcomes were analysed using appropriate statistical methods. Out of 78 patients, trifecta was achieved in 30 (38.4%) patients. There was no statistically significant difference in trifecta between cT1a and cT1b + tumours (p = 0.152). We found a statistically significant difference between the two groups in terms of RENAL scores (p = 0.0005), PADUA score (p = 0.0002), and robotic console time (133.8 ± 42.8 Vs 170 ± 54.8 min for cT1a versus cT1b + , respectively) (p = 0.002). On multivariate analysis, warm ischemia time (p = 0.069), blood loss (p = 0.345), UCS repair (p = 0.691) and GFR reduction (p = 0.152) were not statistically different. There was no statistically significant difference in intraoperative and post-operative complications (p = 0.9317) or length of hospital stay (p = 0.112). Although recurrences were observed in two patients (5.4%) of the cT1b group, there was no statistical difference in the recurrence-free survival at 12 and 24 months. Our study shows that RAPN can be safely done for cT1b + renal tumours. These findings reinforce the view that RAPN should be considered a viable option for cT1b + lesions whenever technically feasible.

Roughness of the renal tumor surface could predict the surgical difficulty of robot-assisted partial nephrectomy

INTRODUCTION

Preoperative prediction of surgical difficulty of partial nephrectomy (PN) is essential to minimize the perioperative complications and to achieve a good surgical outcome. Recently, various scoring systems have been used to evaluate the difficulty of PN including R.E.N.A.L (Radius, Exophytic/Endophytic, Nearness, Anterior/Posterior, Location) nephrometry score. There were no scoring systems evaluating the roughness of the renal tumor surface and we hypothesized that the roughness of the renal tumor surface might affect the surgical difficulty of robot-assisted partial nephrectomy (RAPN). This study aimed to evaluate the impact of roughness of the renal tumor surface on the surgical outcome of RAPN.

METHODS

Overall, 161 patients underwent RAPN performed by the same surgeon between May 2016 and April 2019. We divided those tumors into two groups, like "roughness positive (tumor with roughness of tumor surface)" and "roughness negative (tumor without roughness of tumor surface)" according to the roughness of the endophytic region on preoperative computed tomography images. Clinical and pathological outcomes were compared between the two groups.

RESULTS

Eighty-five and 78 tumors were identified roughness negative and positive, respectively. Cases with roughness positive showed a significantly longer operative time, console time, and ischemia time and had greater blood loss than those with roughness negative. Significant and independent predictors of ischemia time and estimated glomerular filtration rate (eGFR) decrease were roughness of tumor surface, tumor size (not for eGFR decrease), and N score of the R.E.N.A.L nephrometry score.

CONCLUSION

Roughness of renal tumor surface was significantly and positively associated with ischemia time and the eGFR decrease rate.

Factors influencing warm ischemia time in robot-assisted partial nephrectomy change depending on the surgeon's experience

INTRODUCTION

Warm ischemia time (WIT) is a primary concern for robot-assisted laparoscopic partial nephrectomy (RALPN) patients because longer WIT is significantly associated with postoperative deteriorating kidney function. Tumor complexity, determined by the RENAL nephrometry score (RENAL score), can help predict surgical outcomes, but it is unclear what RENAL score and clinical factors affect WIT. This study explored the clinical factors predicting long WIT in experienced surgeon to RALPN.

MATERIALS AND METHODS

In our institute, 174 RALPNs were performed between November 2013 and February 2021, of which 114 were performed by a single surgeon and included in this study. Clinical staging and the total RENAL score were determined based on preoperative CT scans. The cases were divided into three groups based on experience: period 1: 1-38, period 2: 39-76, and period 3: 77-114. The clinical factors associated with longer WIT were analyzed per period.

RESULTS

The overall median tumor diameter was 32 mm, and one patient had a positive surgical margin, but there were no cancer-related deaths. In total, there were 18 complications (15.8%). Periods 2 and 3 had larger tumor diameters (p < 0.01) and worse preoperative kidney function (p = 0.029) than period 1. A RENAL L-component score of 3 was associated with longer WIT in period 3 (odds ratio: 3.900; 95% confidence interval: 1.004-15.276; p = 0.044), but the tumor diameter and the total RENAL score were not.

CONCLUSIONS

A large tumor in the central lesion indicated by the RENAL L-component score was associated with increased WIT in RALPN.

Laparoscopic and Robotic-Assisted Partial Nephrectomy: An Overview of Hot Issues

Laparoscopic partial nephrectomy and robot-assisted partial nephrectomy are attracting increased attention from urologists. They can achieve the same effect of oncology control as radical nephrectomy; moreover, they can offer better preservation of renal function, thus obtaining long-term living benefits. The indications are also expanding, making it possible for larger and more difficult tumors. Laparoscopic partial nephrectomy and robot-assisted partial nephrectomy can be performed by transperitoneal and retroperitoneal approaches, with their individual advantages and limitations. In addition, the renal tumor scoring systems have been widely used and studied in laparoscopic partial nephrectomy and robot-assisted partial nephrectomy. In -order to better preserve renal function, the zero-ischemia technique is widely used. The application of intraoperative imaging technology provides convenience and greater benefits. Besides, whether minimal invasive partial nephrectomy can be performed without stop antiplatelet treatment is still disputed. Clinicians perform substantial exploration and practice to achieve the "trifecta" of surgery: complete resection of the tumor, maximum protection of renal function, and no complications.

Predictive Value of Nephrometry Scores in Nephron-sparing Surgery: A Systematic Review and Meta-analysis

CONTEXT

Over the last decade, several nephrometry scores (NSs) have been introduced with the aim of facilitating preoperative decision making, planning, and counseling in the field of nephron-sparing surgery. However, their predictive role remains controversial.

OBJECTIVE

To describe currently available nephrometry scores and to determine their predictive role for different outcomes by performing a systematic review and meta-analysis of the literature.

EVIDENCE ACQUISITION

PubMed, Embase®, and Web of Science were screened to identify eligible studies. Identification and selection of the reports were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). A pooled analysis of NS predictive role of intraoperative, postoperative, oncological, and functional outcomes was performed. Odds ratio was considered the effect size. All the analyses were performed using Stata 15.0, and statistical significance was set at p≤ 0.05.

EVIDENCE SYNTHESIS

Overall, 51 studies meeting our inclusion criteria were identified and considered for the analysis. Except for one prospective randomized trial, all the studies were retrospective. All the studies were found to be of intermediate quality, except for one of high quality. Most studies assessed the predictive role of the Radius-Exophytic/Endophytic-Nearness-Anterior/Posterior-Location (RENAL) and Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) scores, mostly regarding complications after nephron-sparing surgery. RENAL was an independent predictor of an on-clamp procedure (p< 0.001). Mayo Adhesive Probability score was related to adhesive perinephric fat (p= 0.005). Continuous and high-complexity RENAL scores were predictors of warm ischemia time (WIT; p= 0.006 and p< 0.001, respectively). Continuous (p< 0.001) and high-complexity (p< 0.001) PADUA scores were related to WIT. Continuous and high-complexity RENAL scores were predictors of overall complications (p= 0.002 and p< 0.001, respectively). PADUA score was related to complications both as continuous (p< 0.001) and as a categorical value (p< 0.002). The RENAL scores R=3 (p= 0.008), E=2 (p= 0.039), and hilar location (p= 0.006) were predictors of histological malignancy. Continuous and categorical RENAL scores were independent predictors of an estimated glomerular filtration rate (eGFR) increase (p= 0.006 and p< 0.001, respectively). The Diameter-Axial-Polar score (p= 0.018) and Peritumoral Artery Scoring System (PASS; p= 0.02) were also independent predictors.

CONCLUSIONS

The literature regarding nephrometry scoring systems is sparse, and mostly focused on RENAL and PADUA, which are easy to calculate and have a good correlation with most outcomes. Renal Pelvic Score is the best predictor of pelvicalyceal entry/repair and urine leak, whereas Surgical Approach Renal Ranking and PASS strongly predict surgical approach and renal function variation, respectively. Other nephrometry scores based on mathematical models are limited by their complexity, and they lack evidence supporting their predictive value.

PATIENT SUMMARY

We reviewed the medical literature regarding the use and value of so-called "nephrometry scores," which are scoring systems based on radiological imaging and made to grade the complexity of a renal tumor. We analyzed whether these scoring systems can predict some of the outcomes of patients undergoing surgical removal of renal tumors.

Two-Dimensional Versus Three-Dimensional Laparoscopic Systems in Urology: A Systematic Review and Meta-Analysis

BACKGROUND

Laparoscopy is widely used in the urological field. This systematic review and a meta-analysis were conducted to assess the clinical and surgical efficacy of the three-dimensional (3D) laparoscopic system in comparison with two-dimensional (2D) laparoscopy for treatment of different urological conditions.

METHODS

Following guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses, a systematic literature search in Web of Science, PubMed, Cochrane Library, and EMBase was carried out to identify relevant studies published up to May 2018. Articles published in the English language of both randomized and observational studies comparing 3D and 2D laparoscopic systems in urological surgeries were included. Level of evidence and quality assessments of all included studies were conducted. Interested data were extracted for comparison and meta-analysis.

RESULTS

Our literature search generated 17 studies comparing 3D and 2D laparoscopic systems in different urological surgeries. Of these, 13 studies containing 548 and 449 patients operated on with 2D and 3D laparoscopic systems, respectively, were included for meta-analysis. These 13 studies were divided into three groups according to surgical type. Group 1: Partial nephrectomy (PN); operative time (p = 0.19), estimated blood loss (EBL) (p = 0.51), dissecting time (p = 0.58), and suturing time (p = 0.28) were not statistically significant between 2D and 3D laparoscopic systems. However, warm ischemia time during PN was significantly shorter during 3D laparoscopy (p < 0.00001). Group 2: Pyeloplasty; this procedure showed no significant difference between the two systems. Group 3: Radical prostatectomy (RP); shorter operative time (p < 0.0001) and lower EBL (p = 0.001) were associated with the 3D laparoscopic system.

CONCLUSION

Three-dimensional laparoscopy mainly improves the depth of perception, leading to better visibility, which is important for some complex urological surgeries such as PN, pyeloplasty, and RP. Based on our findings, 3D laparoscopy seems to provide better clinical and surgical outcomes in some urological procedures compared with conventional 2D laparoscopy.

Two-dimensional shear wave elastography of the perirenal fat: Can sticky fat be predicted?

PURPOSE

To evaluate whether two-dimensional (2D) shear wave elastography (SWE) can predict the presence of perirenal sticky fat (PSF) by showing increased perirenal fat stiffness.

METHODS

We prospectively enrolled 28 patients with 31 renal tumors and 10 donor cases. Conventional renal ultrasound (US) and 2D-SWE examination of the perirenal fat were performed. Patient age, gender, body mass index (BMI), largest mass size, PF shear wave velocity (SWV) on both sides were recorded. During surgery, presence of PSF and perirenal fat dissection time (PFDT) were recorded.

RESULTS

Twenty three renal masses were malignant and eight were benign. There were 13 clear cell carcinomas and 10 nonclear cell carcinomas. Eight patients had PSF. Mean PFDT was 13 minutes. PFDT and BMI were significantly increased in the PSF group (p < .05). No statistically significant differences were found in SWVs in patients with and without PSF. There were no significant differences with regard to SWVs between donor cases and patients, tumor side and nontumor side, benign masses and malignant masses, clear cell and nonclear cell tumors. No significant correlations were detected between SWVs and PFDT, mass size, Fuhrman grade and BMI (p > .05).

CONCLUSION

2D-SWE cannot detect PSF.

Nephrometry scores and perioperative outcomes following robotic partial nephrectomy

Objectives:

Based on imaging features, nephrometry scoring systems have been conceived to create a standardized and reproducible way to characterize renal tumor anatomy. However, less is known about which of these individual measures are important with regard to clinically relevant perioperative outcomes such as ischemia time (IT), estimated blood loss (EBL), length of hospital stay (LOS), and change in estimated glomerular filtration rate (eGFR) after robotic partial nephrectomy (PN). We aimed to assess the utility of the RENAL and PADUA scores, their subscales, and C-index for predicting these outcomes.

Materials and Methods:

We analyzed imaging studies from 283 patients who underwent robotic PN between 2008 and 2014 to assign nephrometry scores (NS): PADUA, RENAL and C-index. Univariate linear regression was used to assess whether the NS or any of their subscales were associated with EBL or IT. Multivariable linear regression and linear regression models were created to assess LOS and eGFR.

Results:

The three NS were significantly associated with EBL, IT, LOS, and eGFR at 12 months after surgery. All subscales with the exception of anterior/posterior were significantly associated with EBL and IT. Collecting system, renal rim location, renal sinus, exophytic/endophytic, and nearness to collecting system were significant predictors for LOS. Only renal rim location, renal sinus invasion and polar location were significantly associated with eGFR at 12 months.

Conclusions:

Tumor size and depth are important characteristics for predicting robotic PN outcomes and thus could be used individually as a simplified way to report tumors features for research and patient counseling purposes.

Prediction of Intraoperative Urinary Collecting System Entry in Patients with Peripheral Renal Tumors Undergoing Partial Nephrectomy: Usefulness of Tumor-Centered Multiplanar Reconstruction

OBJECTIVE

To assess the usefulness of tumor-centered multiplanar reconstruction (TC-MPR) for predicting intraoperative urinary collecting system (UCS) entry in patients with peripheral renal tumors undergoing partial nephrectomy (PN).

METHODS

Dynamic computed tomography images of 50 peripheral cT1 renal tumors treated with laparoendoscopic PN were analyzed. TC-MPR generated a digital cross-sectional image showing the tumor center and the closest calyx on a same plane. Patients and tumor characteristics including the distance from the tumor margin to the closest calyx (MPR-distance), and the angle formed by 2 tangent lines from the closest calyx to the tumor (MPR-angle) were assessed.

RESULTS

Intraoperative UCS entry was observed in 15 patients (30%). The patients who experienced intraoperative UCS entry had a higher RENAL score, wider MPR-angle, and shorter MPR-distance than those who did not (p = 0.04, p = 0.001, p < 0.001, respectively). Multivariate analysis identified MPR-angle as an independent factor for intraoperative UCS entry (p < 0.001).

CONCLUSIONS

The spatial information assessed using TC-MPR serves as a predictive factor for intraoperative UCS entry during PN.

Predicting outcomes in partial nephrectomy: is the renal score useful?

INTRODUCTION AND OBJECTIVE

The R.E.N.A.L. nephrometry system (RNS) has been validated in multiple open, laparoscopic and robotic partial nephrectomy series. The aim of this study was to test the accuracy of R.E.N.A.L. nephrometry system in predicting perioperative outcomes in surgical treatment of kidney tumors <7.0cm in a prospective model.

MATERIALS AND METHODS

Seventy-one patients were selected and included in this prospective study. We evaluate the accuracy of RNS in predicting perioperative outcomes (WIT, OT, EBL, LOS, conversion, complications and surgical margins) in partial nephrectomy using ROC curves, univariate and multivariate analyses. R.E.N.A.L. was divided in 3 groups: low complexity (LC), medium complexity (MC) and high complexity (HC).

RESULTS

No patients in LC group had WIT >20 min, versus 41.4% and 64.3% MC and HC groups respectively (p=0.03); AUC=0.643 (p=0.07). RNS was associated with convertion rate (LC:28.6% ; MC:47.6%; HC:77.3%, p=0.02). Patients with RNS <8 were most often subjected to partial nephrectomy (93% x 72%, p=0.03) and laparoscopic partial nephrectomy (56.8% x 28%, p=0.02), AUC=0.715 (p=0.002). The RNS was also associated with operative time. Patients with a score >8 had 6.06 times greater chance of having a surgery duration >180 min. (p=0.017), AUC=0.63 (p=0.059). R.E.N.A.L. score did not correlate with EBL, complications (Clavien >3), LOS or positive surgical margin.

CONCLUSION

R.E.N.A.L. score was a good method in predicting surgical access route and type of nephrectomy. Also was associated with OT and WIT, but with weak accuracy. Although, RNS was not associated with Clavien >3, EBL, LOS or positive surgical margin.

Renal Tumor Anatomic Complexity: Clinical Implications for Urologists

Anatomic tumor complexity can be objectively measured and reported using nephrometry. Various scoring systems have been developed in an attempt to correlate tumor complexity with intraoperative and postoperative outcomes. Nephrometry may also predict tumor biology in a noninvasive, reproducible manner. Other scoring systems can help predict surgical complexity and the likelihood of complications, independent of tumor characteristics. The accumulated data in this new field provide provocative evidence that objectifying anatomic complexity can consolidate reporting mechanisms and improve metrics of comparisons. Further prospective validation is needed to understand the full descriptive and predictive ability of the various nephrometry scores.

Utility of patient-specific silicone renal models for planning and rehearsal of complex tumour resections prior to robot-assisted laparoscopic partial nephrectomy

OBJECTIVE

To describe our experience using patient-specific tissue-like kidney models created with advanced three-dimensional (3D)-printing technology for preoperative planning and surgical rehearsal prior to robot-assisted laparoscopic partial nephrectomy (RALPN).

PATIENTS AND METHODS

A feasibility study of 10 patients with solid renal masses who underwent RALPN after preoperative rehearsal using 3D-print kidney models. A single surgeon performed all surgical rehearsals and procedures. Using standard preoperative imaging and 3D reconstruction, we generated pre-surgical models using a silicone-based material. All surgical rehearsals were performed using the da Vinci^® robotic system (Intuitive Surgical Inc., Sunnyvale, CA, USA) before the actual procedure. To determine construct validity, we compared resection times between the model and actual tumour in a patient-specific manner. Using 3D laser scanning in the operating room, we quantified and compared the shape and tumour volume resected for each model and patient tumour.

RESULTS

We generated patient-specific models for 10 patients with complex tumour anatomy. R.E.N.A.L. nephrometry scores were between 7 and 11, with a mean maximal tumour diameter of 40.6 mm. The mean resection times between model and patient (6:58 vs 8:22 min, P = 0.162) and tumour volumes between the computer model, excised model, and excised tumour (38.88 vs 38.50 vs 41.79 mm³ , P = 0.98) were not significantly different.

CONCLUSIONS

We have developed a patient-specific pre-surgical simulation protocol for RALPN. We demonstrated construct validity and provided accurate representation of enucleation time and resected tissue volume. This simulation platform can assist in surgical decision-making, provide preoperative rehearsals, and improve surgical training.

Selective arterial clamping does not improve outcomes in robot-assisted partial nephrectomy: a propensity-score analysis of patients without impaired renal function

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.

Value of Nephrometry Score Constituents on Perioperative Outcomes and Split Renal Function in Patients Undergoing Minimally Invasive Partial Nephrectomy

OBJECTIVE

To assess the relationship between individual nephrometry score (NS) constituents (RENAL) on perioperative outcomes and renal function of the surgical kidney in patients undergoing laparoscopic partial nephrectomy or robotic-assisted partial nephrectomy.

MATERIALS AND METHODS

Two hundred forty-five patients who underwent laparoscopic partial nephrectomy or robotic-assisted partial nephrectomy between 2005 and 2014 were retrospectively reviewed. Each renal mass' NS was calculated from preoperative computed tomography imaging. Multivariate regression analysis was used to evaluate the effect of NS variables on perioperative outcomes and change in overall renal function (as estimated by glomerular filtration rate) from preoperative to 1-year postoperative. A cohort analysis assessed the effect of NS variables on change in split renal function of the surgical kidney from pre- to postoperative based on nuclear medicine renal scintigraphy.

RESULTS

Tumor radius (R), endophytic nature (E), and nearness to collecting system (N) variables significantly and incrementally predicted a longer operative time and warm ischemia time. Overall renal function based on glomerular filtration rate was not affected by any NS variable. However, percent function of the surgical kidney by renal scintigraphy significantly decreased postoperatively as R and E values increased.

CONCLUSION

R, E, and N were associated with significant changes in warm ischemia time and operative time. R and E were associated with a significant decrease in split renal function of the surgical kidney at 1 year after surgery but not with overall renal function. R, E, and N are the NS constituents most relevant to perioperative outcomes and postoperative differential renal function after partial nephrectomy.

A Literature Review of Renal Surgical Anatomy and Surgical Strategies for Partial Nephrectomy

CONTEXT

A detailed understanding of renal surgical anatomy is necessary to optimize preoperative planning and operative technique and provide a basis for improved outcomes.

OBJECTIVE

To evaluate the literature regarding pertinent surgical anatomy of the kidney and related structures, nephrometry scoring systems, and current surgical strategies for partial nephrectomy (PN).

EVIDENCE ACQUISITION

A literature review was conducted.

EVIDENCE SYNTHESIS

Surgical renal anatomy fundamentally impacts PN surgery. The renal artery divides into anterior and posterior divisions, from which approximately five segmental terminal arteries originate. The renal veins are not terminal. Variations in the vascular and lymphatic channels are common; thus, concurrent lymphadenectomy is not routinely indicated during PN for cT1 renal masses in the setting of clinically negative lymph nodes. Renal-protocol contrast-enhanced computed tomography or magnetic resonance imaging is used for standard imaging. Anatomy-based nephrometry scoring systems allow standardized academic reporting of tumor characteristics and predict PN outcomes (complications, remnant function, possibly histology). Anatomy-based novel surgical approaches may reduce ischemic time during PN; these include early unclamping, segmental clamping, tumor-specific clamping (zero ischemia), and unclamped PN. Cancer cure after PN relies on complete resection, which can be achieved by thin margins. Post-PN renal function is impacted by kidney quality, remnant quantity, and ischemia type and duration.

CONCLUSIONS

Surgical renal anatomy underpins imaging, nephrometry scoring systems, and vascular control techniques that reduce global renal ischemia and may impact post-PN function. A contemporary ideal PN excises the tumor with a thin negative margin, delicately secures the tumor bed to maximize vascularized remnant parenchyma, and minimizes global ischemia to the renal remnant with minimal complications.

PATIENT SUMMARY

In this report we review renal surgical anatomy. Renal mass imaging allows detailed delineation of the anatomy and vasculature and permits nephrometry scoring, and thus precise, patient-specific surgical planning. Novel off-clamp techniques have been developed that may lead to improved outcomes.

Review of robot-assisted partial nephrectomy in modern practice

Partial nephrectomy (PN) is currently the standard treatment for T1 renal tumors. Minimally invasive PN offers decreased blood loss, shorter length of stay, rapid convalescence, and improved cosmesis. Due to the challenges inherent in laparoscopic partial nephrectomy, its dissemination has been stifled. Robot-assisted partial nephrectomy (RAPN) offers an intuitive platform to perform minimally invasive PN. It is one of the fastest growing robotic procedures among all surgical subspecialties. RAPN continues to improve upon the oncological and functional outcomes of renal tumor extirpative therapy. Herein, we describe the surgical technique, outcomes, and complications of RAPN.

Predicting Renal Parenchymal Loss after Nephron Sparing Surgery

PURPOSE

We analyze the relationship among various patient, operative and tumor characteristics to determine which factors correlate with renal parenchymal volume loss after nephron sparing surgery using a novel 3-dimensional volume assessment.

MATERIALS AND METHODS

We conducted a retrospective review of an institutional database of patients who underwent nephron sparing surgery from 1992 to 2014 for a localized renal mass. Tumors were classified according to the R.E.N.A.L. nephrometry system. Using 3-dimensional reconstruction imaging software, preoperative and postoperative renal parenchymal volume was calculated for the ipsilateral and contralateral kidney.

RESULTS

A total of 158 patients were analyzed. Mean patient age was 58.7 years and mean followup was 40.1 months. Mean preoperative tumor volume was 34.0 cc and mean tumor dimension was 3.4 cm. Mean R.E.N.A.L. nephrometry score was 6.2, with 60.1%, 34.2% and 5.7% of tumors classified as low, medium and high complexity, respectively. Mean change in renal parenchymal volume after nephron sparing surgery was -15.3% for the ipsilateral kidney and -6.8% for total kidney volume. On univariate analysis ischemia time, tumor size, R.E.N.A.L. nephrometry score, complexity grouping and the individual nephrometry components of tumor size, percent exophytic, anterior/posterior, depth and tumor proximity to the renal artery or vein were associated with greater renal parenchymal volume loss. On multivariate analysis only ischemia time, tumor size, posterior location and percent exophytic were independently associated with more renal parenchymal volume loss.

CONCLUSIONS

Using precise 3-dimensional volumetric analysis we found that ischemia time, tumor size and endophytic/exophytic properties of a localized renal mass are the most important determinants of renal parenchymal volume loss.

Significant impact of R.E.N.A.L. nephrometry score on changes in postoperative renal function early after robot-assisted partial nephrectomy

BACKGROUND

Our objective was to evaluate the significance of the R.E.N.A.L. nephrometry score (RNS)--developed to quantitatively evaluate the complexity of renal tumors in a reproducible manner--in perioperative and renal functional outcomes following robot-assisted partial nephrectomy (RAPN).

METHODS

This study assessed 48 consecutive patients with renal tumors who underwent RAPN. Preoperative RNS for each patient was calculated, and its impact on several parameters associated with perioperative outcomes, including postoperative renal function, was investigated with Spearman's rank correlation test.

RESULTS

Mean RNS in the 48 patients was 6.8; of these 48 patients, 21 (43.7%), 24 (50.0%), and three (6.3%) were classified into low-, moderate-, and high-complexity groups, respectively. The RNS was significantly correlated with resected tumor weight and postoperative changes in estimated glomerular filtration rate (eGFR) at both 1 and 4 weeks--but not age, body mass index (BMI), preoperative eGFR, operative time, warm ischemia time, estimated blood loss, postoperative complications, or eGFR-- after RAPN. No component of the RNS (R: radius; E: exophytic/endophytic properties; N: nearness of tumor to the collecting system or sinus; A: anterior/posterior; L: location relative to polar lines) alone had a significant impact on postoperative changes in eGFR at 1 and 4 weeks, whereas resected tumor weight was significantly associated with the R and E subcategories.

CONCLUSIONS

Measurement of total RNS is useful for predicting renal functional outcomes early after RAPN.

Robotic nephron-sparing surgery for renal tumors: Current status

There have been a number of advances in robotic partial nephrectomy (RPN) for renal masses. We reviewed these advances with emphasis on the evolution of technique and outcomes as well as the expanding indications for RPN. Literature in the English language was reviewed using the National Library of Medicine database. Relevant articles were extracted, and their citations were utilized to broaden our search. The identified articles were reviewed and summarized with a focus on novel developments. RPN is an evolving procedure and is an emerging viable alternative to laparoscopic partial nephrectomy and open partial nephrectomy with favorable outcomes. The contemporary techniques used for RPN demonstrate excellent perioperative outcomes. The short-term oncologic outcomes are comparable to those of laparoscopic and open surgical approaches. Further studies are needed to assess long-term oncologic control.

Internal validation of the renal pelvic score: a novel marker of renal pelvic anatomy that predicts urine leak after partial nephrectomy

OBJECTIVE

To internally validate the renal pelvic score (RPS) in an expanded cohort of patients undergoing partial nephrectomy (PN).

MATERIALS AND METHODS

Our prospective institutional renal cell carcinoma database was used to identify all patients undergoing PN for localized renal cell carcinoma from 2007 to 2013. Patients were classified by RPS as having an intraparenchymal or extraparenchymal renal pelvis. Multivariate logistic regression models were used to examine the relationship between RPS and urine leak.

RESULTS

Eight hundred thirty-one patients (median age, 60 ± 11.6 years; 65.1% male) undergoing PN (57.3% robotic) for low (28.9%), intermediate (56.5%), and high complexity (14.5%) localized renal tumors (median size, 3.0 ± 2.3 cm; median nephrometry score, 7.0 ± 2.6) were included. Fifty-four patients (6.5%) developed a clinically significant or radiographically identified urine leak. Seventy-two of 831 renal pelvises (8.7%) were classified as intraparenchymal. Intrarenal pelvic anatomy was associated with a markedly increased risk of urine leak (43.1% vs 3.0%; P <.001), major urine leak requiring intervention (23.6% vs 1.7%; P <.001), and minor urine leak (19.4% vs 1.2%; P <.001) compared with that in patients with an extrarenal pelvis. After multivariate adjustment, RPS (intraparenchymal renal pelvis; odds ratio [OR], 24.8; confidence interval [CI], 11.5-53.4; P <.001) was the most predictive of urine leak as was tumor endophyticity ("E" score of 3 [OR, 4.5; CI, 1.3-15.5; P = .018]), and intraoperative collecting system entry (OR, 6.1; CI, 2.5-14.9; P <.001).

CONCLUSION

Renal pelvic anatomy as measured by the RPS best predicts urine leak after open and robotic partial nephrectomy. Although external validation of the RPS is required, preoperative identification of patients at increased risk for urine leak should be considered in perioperative management and counseling algorithms.

R.E.N.A.L. Nephrometry scoring: how well correlated are urologist, radiologist, and collaborator scores?

PURPOSE

R.E.N.A.L. Nephrometry Score (NS) is an imaging-based (CT/MRI) scoring system commonly used by urologists to standardize the reporting of renal masses by enabling quantification of anatomical characteristics. We sought to examine the inter-rater correlation of NS between urologists, radiologists, and tumor-board collaborators.

METHODS

We identified adult patients undergoing partial or radical nephrectomy over 10 years (n=2450). Patients with autosomal dominant polycystic kidney disease (ADPKD), metastatic disease, masses >10 cm, and studies in which the study urologists or radiologists partook in patient care were excluded. Preoperative imaging was evaluated and patients with multiphasic CT available were included. Scans were provided to the reviewers to evaluate with a R.E.N.A.L. nephrometry questionnaire. Results were analyzed using kappa correlation coefficients.

RESULTS

One hundred twenty patients met inclusion criteria with mean age of 59.5 years. The majority of cases were partial nephrectomies (72%). Eighty-five percent of the tumors were malignant, with 26% having high-grade histology. The mean (standard deviation) overall NS was 6.8 (1.9) with fair correlation among reviewers (κ=0.222). Collaborators had the highest inter-rater correlation, ranging from 0.41 to 0.84 for NS component scores, compared with 0.42-0.85 for radiologists and 0.36-0.86 for urologists. "R" scores were best correlated (κ>0.8). NS correlation ranged between 0.16 and 0.31 for the groups while the NS complexity category correlation ranged between 0.50 and 0.61.

CONCLUSIONS

Despite being naive to NS, inter-radiologist scoring patterns were better correlated than inter-urologist. The urologist and radiologist collaborating in tumor board showed the highest agreement, suggesting that a multidisciplinary approach in the characterization of renal masses may provide benefit to patient management.

Factors Influencing the Operative Approach to Renal Tumors: Analyses According to RENAL Nephrometry Scores

Purpose

To evaluate the relationship between RENAL nephrometry score (RNS) and operative approach for renal masses.

Materials and Methods

This study included 206 consecutive patients who underwent renal tumor surgery between January 2008 and October 2012. We divided the patients into four groups by surgical approach: open radical nephrectomy (ORN, 53 patients), laparoscopic radical nephrectomy (LRN, 83 patients), open partial nephrectomy (OPN, 31 patients), and laparoscopic partial nephrectomy (LPN, 39 patients). We retrospectively assessed the RNS for each surgery group and evaluated the relationship between this score and operative approach.

Results

The mean RNSs of the ORN, LRN, OPN, and LPN groups were 9.75, 8.35, 6.72, and 5.76, respectively. When the RNS was analyzed according to nephron-sparing, the mean RNSs of the RN groups (ORN and LRN) and the PN groups (OPN and LPN) were significantly different (8.89 and 6.09, respectively; p<0.001). All the individual components of the RNS were significantly different between RN and PN. In the RN groups, the criteria for open versus laparoscopic surgery were based on tumor size ('R' score=2.43 for open, 1.54 for laparoscopic, p<0.001) and tumor location relative to the polar line ('L' score=2.55 for open, 2.09 for laparoscopic, p=0.006). In the PN groups, the criteria for open or laparoscopic surgery were based only on exophytic/endophytic property ('E' score=1.87 for open, 1.41 for laparoscopic, p=0.046).

Conclusions

The RNS was significantly different in all surgery groups. The decision to take a laparoscopic approach was primarily influenced by the R and L scores for RN and by the E score for PN.

Risk factors for postoperative hemorrhage after partial nephrectomy

Purpose

To evaluate the frequency and clinical characteristics of postoperative hemorrhage as a complication of partial nephrectomy.

Materials and Methods

The demographics, physical statistics, tumor size, R.E.N.A.L. nephrometry score, operative method, warm ischemic time, and presence of postoperative hemorrhage and its severity and method of intervention were examined in 300 partial nephrectomy patients in two medical centers (Stanford Medical Center and Kyung Hee University Medical Center) between March 2000 and March 2012.

Results

Of the 300 subjects, 13 (4.3%) experienced postoperative hemorrhage severe enough to require intervention more invasive than transfusion (Clavien grade III or higher). Univariate analysis of the bleeding and nonbleeding groups showed that whereas age, ischemic time, tumor size and stage, body mass index, American Society of Anesthesiologists class, and operative method did not differ significantly, the exophyticity (E) score was significantly higher for severe postoperative hemorrhage (p=0.04). However, multivariate analysis showed none of the factors to differ significantly. In most of the cases requiring intervention, selective embolization was sufficient, but in one case explorative laparotomy and nephrectomy were required. Clinical characteristics varied significantly among severe hemorrhage cases, with time of onset ranging from the first to the 30th postoperative day and symptoms presenting in a diverse manner, such as gross hematuria and pleuritic chest pain. Computed tomography and angiographic findings were consistent with either arteriovenous fistula or pseudoaneurysms.

Conclusions

Severe hemorrhage after partial nephrectomy is rare. Nonetheless, with the great variability in presenting symptoms and time of onset after surgery, surgeons should exercise great vigilance during the postoperative care of partial nephrectomy patients.

Current Status of Laparoscopic Partial Nephrectomy

<p>Recently, nephron-sparing, minimally invasive surgery of small renal masses has become popular. The most typical surgery is laparoscopic partial nephrectomy (LPN). However, due to technical difficulties, the indications for LPN had been limited to small, exophytic, and peripheral tumors. This paper introduces current status of oncological outcomes and technical considerations.</p>

MR renographic measurement of renal function in patients undergoing partial nephrectomy

OBJECTIVE

The purpose of this review is to describe the role of functional renal MRI, or MR renography, in the care of patients with renal masses undergoing partial nephrectomy.

CONCLUSION

MR renography can be used to monitor renal functional outcome for patients undergoing partial nephrectomy and may help guide patient selection in this population with elevated risk of chronic kidney disease.

Clinical analysis of the PADUA and the RENAL scoring systems for renal neoplasms: a retrospective study of 245 patients undergoing laparoscopic partial nephrectomy

OBJECTIVE

To investigate the clinical significance of preoperative aspects and dimensions used for anatomic (PADUA) and radius exophytic/endophytic nearness anterior/posterior location (RENAL) scoring systems for renal neoplasms in patients undergoing laparoscopic partial nephrectomy.

METHODS

A retrospective analysis was carried out on clinical data of 245 Chinese patients with renal neoplasms undergoing laparoscopic partial nephrectomy from June 2008 to June 2012. The perioperative complications and variables, as well as PADUA and RENAL score, were compared.

RESULTS

The PADUA and RENAL scoring systems were significantly associated with percent change in estimated glomerular filtration rate (P = 0.032 and P = 0.026 respectively), whereas the RENAL scoring system was also significantly associated with warm ischemia time (P = 0.032). On multivariate analysis, both scores were able to predict percent change in estimated glomerular filtration rate (PADUA, P = 0.011; RENAL, P = 0.028). There were no significant associations between the two scoring systems assessed and the occurrence of complications or tumor stage. The correlation between PADUA classification and RENAL nephrometry score was significant (P < 0.0001). Fleiss' generalized kappa was 0.69-0.89 for the various components of the PADUA score and 0.67-0.89 for the RENAL nephrometry components.

CONCLUSIONS

The PADUA classification and RENAL nephrometry score are comprehensive assessment tools for delineating renal tumor anatomy. The reproducibility of the PADUA and RENAL scores is substantial, but further research is required to evaluate its performance in more accurately predicting operative and patient-related outcomes.

Partial nephrectomy--contemporary indications, techniques and outcomes

Increased detection of the small renal mass over the last two decades has led to greater utilization of partial nephrectomy techniques. Appreciation of the negative impact of chronic renal impairment has resulted in partial nephrectomy surpassing radical nephrectomy as the preferred treatment for technically feasible lesions. Indeed the management of localized renal tumours has become focused on techniques that maximally preserve nephron quantity and quality, and therefore maximize renal function after surgery. Postoperative renal function is determined primarily by three factors: preoperative renal function, volume of renal mass preserved and surgical renal ischaemia. Minimization of surgical ischaemia is achieved by early unclamping and unclamped (zero ischaemia) techniques. In addition, laparoscopic and robotic approaches to nephron-sparing surgery have significantly reduced the morbidity of the partial nephrectomy procedure compared with the traditional open approach. The contemporary techniques used for partial nephrectomy demonstrate excellent renal functional and oncological outcomes and minimize perioperative complications.