Excisional Volume Loss Research Articles

No ischemia technique, parenchymal preservation and age are the most important determinants of renal function after partial nephrectomy

The aim of the present study was to compare the outcomes of Off-Clamp to On -Clamp approach during robot-assisted partial nephrectomy (RAPN). Retrospective study of 940patients who underwent a RAPN between 2007 and 2015 for cT1a tumors using On-Clamp or Off-Clamp approaches. Patient with solitary kidney or multifocal were excluded. Overall, 103patients underwent Off-Clamp approach and 37 patients On-Clamp approach. We matched the patients in terms of tumor size, Charlson comorbidity index and R.E.N.A.L. score. At all, 309patients from the On-Clamp were matched to the Off-Clamp group. We compared the clinic-pathological characteristics, perioperative morbidity and late functional outcomes between the 2 propensity score matched groups. Limitation included retrospective analysis. After matching, there were no difference in clinic-pathological characteristics in terms of gender, age, race, body mass index, Charlson comorbidity index, American Society of Anesthesiologists score, baseline estimated glomerular filtration rate (e-GFR), tumor size, R.E.N.A.L. score complexity, hilar (H) location between the 2groups. Regarding perioperative outcomes; while operative time (P=0,4), estimated blood loss (P=0,28), Clavien grade III-IV complications (P=0,8) surgical reoperation (P=1), 30-day readmission (P=1), positive surgical margin (5,5% vs. 5,8%, P=0,9) were comparable between the 2 groups, there were significant difference in excisional volume loss (median, 7,08 vs. 3,51cm3, P<0,01), e-GFR decline (median, -9,7 vs. -2,2ml/min/1,73 m2, P<0,01), percent of e-GFR preservation (median, 87% vs. 97%, P<0,01), and CKD upstaging (36,5% vs. 23,3%, P=0,01), Off-Clamp approach (P=0,01), and age (P=0,02) were predictors of renal function preservation, whereas excisional volume loss (OR=1,035, CI 95% (1,015-1,06), P<0,01) predicted upstaging. RAPN for selected renal mass using Off-Clamp approach offered renal functional advantage over On-Clamp, without adding morbidities. While no ischemia technique was associated with less excisional volume loss, Off-Clamp approach, and age were independent predictors of renal function preservation. Clinical significance of these findings in various clinical settings will require further investigation.

Role Of Robot-Assisted Partial Nephrectomy For Renal Cell Carcinomas In The Purpose Of Nephron Sparing.

IntroductionSurgery remains the standard treatment for localized renal cell carcinomas, and partial nephrectomy is considered before radical nephrectomy with the aim of preserving renal function. This study aimed to compare robot-assisted and open partial nephrectomy for the purpose of nephron sparing.Materials and methodsWe retrospectively enrolled consecutive patients who received partial nephrectomy at a single tertiary medical center from January 2008 to January 2015. Medical records and radiographic images were reviewed. We analyzed the patients’ general characteristics, underlying disease, complications, length of hospital stay, renal tumor complexity, surgery type, renal function, and specimen and tumor size. A comparison between open and robot-assisted nephrectomy groups was performed.ResultsA total of 136 patients were enrolled, with a male to female ratio of 2:3 and a mean age of 57.8 years. Of these, 71 and 65 patients received open and robot-assisted surgery, respectively. Compared with the open group, patients who underwent robot-assisted surgery were significantly younger (56.0 versus 60.1 years old), had a longer operative time (303 versus 224 min), and a lower kidney ischemic time (33.4 versus 46.9 min). Given similar tumor sizes, the tumor-to-excision ratio was significantly higher in the robot-assisted group (51.7% versus 39.8%), and the excisional volume loss (EVL) was smaller (12.7 versus 19.6 mL). Preoperative glomerular filtration rate and EVL were significant predictors of long-term renal function preservation in the multivariate analysis.ConclusionWhen performing partial nephrectomy, a robot-assisted procedure could increase the accuracy of excision without increasing the risk of positive surgical margin. Lower EVL could assist in better long-term postoperative renal function preservation.

Renal volume matters: Assessing the association between excisional volume loss and renal function after partial nephrectomy

To investigate the oncological and functional outcomes after partial nephrectomy for clinical stage T1 (cT1) renal cell carcinoma (RCC), and assess the association between excisional volume loss (EVL) and postoperative renal function. We retrospectively reviewed 150 patients with cT1 RCC undergoing partial nephrectomy from 2002 to 2016. End-point evaluation was assessed by recurrence free survival (RFS), overall survival (OS), stage III and stage IV chronic kidney disease (CKD). Regression models were used to determine the risk factors of CKD after surgery. The relationship between EVL and renal function decline was evaluated using Spearman correlation method. Ninety patients with clinical stage T1a (cT1a) tumors and 60 patients with clinical stage T1b (cT1b) tumors were included. There were no differences in RFS, OS, and risk of stage III and stage IV CKD between the two groups. In Cox regression models, multivariate analysis showed that preoperative estimated glomerular filtration rate (eGFR) was an independent risk factor for developing stage III (hazard ratio 0.937, P<0.001) and stage IV CKD (hazard ratio 0.929, P=0.027). EVL was significantly associated with postoperative eGFR decrease. (Correlation Coefficient=0.325, P=0.003). Patients with cT1a and cT1b RCC have comparable oncological and functional outcome after partial nephrectomy, and preoperative eGFR is an independent factor to predict developing CKD. EVL has influence on the postoperative renal function decline.

"At-risk" kidney: How surgical factors influence renal functional preservation after partial nephrectomy.

To investigate the influence of surgical modifiable factors on chronic kidney disease upstaging in a contemporary cohort of patients with normal and "at-risk" kidneys undergoing partial nephrectomy. We reviewed 778 consecutive patients with (n=634)/without (n=144) chronic kidney disease or risk factors for chronic kidney disease in our institutional partial nephrectomy database. Chronic kidney disease upstaging was assessed using glomerular filtration rate measurements preoperatively and at 3-12months postoperatively. Using a multivariate logistic regression, baseline clinicodemographic factors, and the operative measurements of excisional volume loss and warm and cold ischemia time on rates of chronic kidney disease upstaging were determined. Marginal effects were used to analyze the impact of ischemia time and generate interaction curves. Chronic kidney disease/risk factors for chronic kidney disease had equivalent rates of chronic kidney disease upstaging as the healthy kidney cohort (31.5% vs 38.2%, P=0.15). Of the entire cohort, 2.8% were upstaged to stageIV-V chronic kidney disease. Multivariate analysis found a significant association between chronic kidney disease upstaging and excisional volume loss in both cohorts (no chronic kidney disease/risk factors for chronic kidney disease: odds ratio 1.63, P=0.04; chronic kidney disease/risk factors for chronic kidney disease: odds ratio 1.42, P=0.001). Only in the chronic kidney disease/risk factors for chronic kidney disease cohort, there was an association between ischemia type/duration and chronic kidney disease upstaging (odds ratio 1.04, P=0.04). Warm ischemia began to predict an increased risk of chronic kidney disease upstaging at 17.6min, which became statistically significant at 49min. Chronic kidney disease upstaging is common after partial nephrectomy. Although volume loss unequivocally affects rates of upstaging irrespective of baseline renal function, warm ischemia time disproportionately influences "at-risk" kidneys. Therefore, strong consideration should be given to minimizing volume loss and using cold ischemia when extended clamp times are anticipated in "at-risk" kidneys.

Early Unclamping Laparoscopic Partial Nephrectomy for Complex Renal Tumor: Data from a Chinese Cohort

Objective: To evaluate the efficacy and safety of early unclamping laparoscopic partial nephrectomy (LPN) for complex renal tumor relative to the standard artery clamping technique (SCT). Methods: Sixty-one patients with complex renal tumor (RENAL score ≥7) underwent LPN at our institution from January 2013 to April 2017. LPN was performed via SCT in 32 patients and via the early unclamping technique (EUT) in 29 patients. Operation time, warm ischemia time (WIT), blood loss, bleeding requiring transfusion, tumor volume, excisional volume loss (EVL), complications, and renal function before and after operation of the affected kidney were compared between the groups. Results: All surgeries were successful without conversion to open or nephrectomy. EUT reduced the WIT (p < 0.001) but did not increase the complication rate (p = 0.322). Although the tumor volume and EVL were larger in the EUT than in the SCT group (p = 0.011, p = 0.001), glomerular filtration rate (GFR) reduction in the affected kidney did not significantly differ between the groups (p = 0.120). Conclusion: Early unclamping LPN for complex renal tumor is safe and efficient. Additionally, the EUT could expand the application of LPN in complex renal tumors, and make this challenging surgery easier and safer.

Variability in Partial Nephrectomy Outcomes: Does Your Surgeon Matter?

BackgroundUnderstanding physician-level discrepancies is increasingly a target of US healthcare reform for the delivery of quality-focused patient care. ObjectiveTo estimate the relative contributions of patient and surgeon characteristics to the variability in key outcomes after partial nephrectomy (PN). Design, setting, and participantsRetrospective review of 1461 patients undergoing PN performed by 19 surgeons between 2011 and 2016 at a tertiary care referral center. InterventionPN for a renal mass. Outcomes measurements and statistical analysisHierarchical linear and logistic regression models were built to determine the percentage variability contributed by fixed patient and surgeon factors on peri- and postoperative outcomes. Residual between- and within-surgeon variability was calculated while adjusting for fixed factors. Results and limitationsOn null hierarchical models, there was significant between-surgeon variability in operative time, estimated blood loss (EBL), ischemia time, excisional volume loss, length of stay, positive margins, Clavien complications, and 30-d readmission rate (all p<0.001), but not chronic kidney disease upstaging (p=0.47) or percentage preservation of glomerular filtration rate (p=0.49). Patient factors explained 82% of the variability in excisional volume loss and 0–32% of the variability in the remainder of outcomes. Quantifiable surgeon factors explained modest amounts (10–40%) of variability in intraoperative outcomes, and noteworthy amounts of variability (90–100%) in margin rates and patient morbidity outcomes. Immeasurable surgeon factors explained the residual variability in operative time (27%), EBL (6%), and ischemia time (31%). ConclusionsThere is significant between-surgeon variability in outcomes after PN, even after adjusting for patient characteristics. While renal functional outcomes are consistent across surgeons, measured and unmeasured surgeon factors account for 18–100% of variability of the remaining peri- and postoperative variables. With the increasing utilization of value-based medicine, this has important implications for the goal of optimizing patient care. Patient summaryWe reviewed our institutional database on partial nephrectomy performed for renal cancer. We found significant variability between surgeons for key outcomes after the intervention, even after adjusting for patient characteristics.

Reevaluating Warm Ischemia Time as a Predictor of Renal Function Outcomes After Robotic Partial Nephrectomy

ObjectiveTo explore whether variation of warm ischemia time (WIT) is associated with functional and perioperative outcomes following robotic partial nephrectomy (RPN). Materials and MethodsSix hundred sixty eight patients, each with 2 kidneys, undergoing RPNs for a cT1 tumor were identified from a U.S. multi-institutional database. The associations between WIT, normal excisional volume loss (EVL), and surgical and renal function outcomes, including acute kidney injury at discharge and percent change in eGFR at up to 24 months post-RPN, were evaluated using Spearman's rank correlation test as well as multivariable models controlling for tumor, surgeon, and patient characteristics. ResultsWIT was weakly correlated with EVL (r = 0.32, P < .001), blood loss (r = 0.34, P < .001), and length of stay (r = 0.35, P < .001). WIT was found to be significantly associated with acute kidney injury at discharge (odds ratio = 6.23; confidence interval 1.52, 30.39). Extended WIT was not found to be significantly associated with renal function decline at 1 year post RPN (P > .05). ConclusionExtended WIT is associated with worse perioperative outcomes. While controlling for tumor size and EVL, effects on short-term renal function were still seen after as short as 20 minutes. Efforts to limit warm ischemia time should continue to be implemented during RPN to maximize postoperative renal function.

The Synergistic Influence of Ischemic Time and Surgical Precision on Acute Kidney Injury After Robotic Partial Nephrectomy

To examine the dynamic and potentially synergistic influence of warm ischemia time (WIT) and excisional volume loss (EVL) on predicted rates of postpartial acute kidney injury (AKI) across a range of tumor complexities, and to investigate whether these modifiable variables sensitize the kidney to each other's damaging influence. We retrospectively reviewed 1245 patients between 2006 and 2016 with bilateral kidneys and enhancing renal masses in our single-institution robotic partial nephrectomy (PN) database. EVL was calculated as the difference between specimen and tumor volume based on pathologic measurements. Multivariate logistic regressions, followed by marginal effects, were run to examine the interaction of ischemia type, EVL, and radius, exophytic/endophytic properties, nearness of deepest tumor portion to collecting system or sinus, anterior/posterior and location relative to polar line score on rates of AKI. We found a significant interaction effect of WIT and log EVL on predicted AKI (P < .001). Each doubling of EVL caused a 4.03% and 8.46% increased probability of AKI for WIT of <25 and >25 minutes, respectively. At an EVL of >5.5 cm3, prolonged WIT had statistically greater odds of causing AKI. These predicted effects on AKI were amplified for increasing radius, exophytic/endophytic properties, nearness of deepest tumor portion to collecting system or sinus, anterior/posterior and location relative to polar line scores (P < .001). Although the adverse functional effects of WIT and parenchymal volume loss during PN have previously been described in isolation, our findings suggest that their influence on AKI is synergistic, especially in complex tumors. As such, additional attention should be given to limiting warm ischemia and maximizing surgical precision to avoid a "double hit" on postoperative renal function.

Excisional Precision Matters: Understanding the Influence of Excisional Volume Loss on Renal Function After Partial Nephrectomy

Renal function after partial nephrectomy (PN) may depend on modifiable factors including ischemia time, excision of healthy parenchyma (excisional volume loss, EVL), and reconstructive methods. We retrospectively reviewed our institutional robotic PN database to identify the predictors of glomerular filtration rate (GFR) preservation (GFR-P) at 3–12 mo postoperatively, during which GFR decline plateaus. Baseline clinical, sociodemographic, and radiologic characteristics were captured. Univariate and multivariate (MV) linear regression analyses were performed and marginal effects were employed to examine the relative effect of EVL on renal function. A total of 647 patients who underwent robotic PN had GFR data at a median follow-up of 6 mo. On MV models, EVL was significantly correlated with GFR-P following log transformation (p=0.001). Each doubling of EVL caused a 1.5% decrease in GFR-P. Ischemia time and tumor complexity were not significantly associated with GFR-P. In summary, GFR-P after PN appears to be significantly associated with the excised volume of benign parenchyma. Patient summaryAt a high-volume tertiary care center, we investigated the impact of surgical factors on kidney function after kidney cancer surgery. We found that the surgical precision with which the tumor is excised significantly impacts kidney function at 3–12 mo after surgery.

Predictors of Excisional Volume Loss in Partial Nephrectomy: Is There Still Room for Improvement?

Since volume loss is the most important modifiable determinant of long-term renal function after partial nephrectomy, there is great interest in ways to reduce the loss of healthy parenchyma. We retrospectively reviewed 880 partial nephrectomies to identify predictors of excisional volume loss (EVL), based on pathologic assessment. After stepwise variable selection, we assessed age, sex, solitary kidney status, tumor size, endophytic property, estimated blood loss, surgical approach, and surgeon volume for association with EVL using multiple regression. Male sex (p<0.01), larger tumors (p<0.01), endophytic tumors (p=0.01), open approach (p<0.01), increased bleeding (p<0.01), and higher surgeon volume (p<0.01) were independently associated with greater EVL. Approach strongly influenced EVL with open surgery having 7.8 cm3 more EVL than robotic surgery. Negative surgical margins (95.7% vs 94.1%, p=0.32) did not differ between open and robotic approaches, respectively. EVL is associated with patient, tumor, and especially provider factors, suggesting that volume preservation may be improved with surgical optimization. Lack of percent volume loss data, which precluded assessment of EVL's impact on long-term renal function, is a limitation. Patient summaryWe found that surgical approach affects the quantity of healthy kidney removed during cancer surgery, suggesting that there is room for further surgical improvement.