Association Between Warm Ischemia Time and Renal Parenchymal Atrophy After Partial Nephrectomy

The evolving management of small renal masses

Small renal masses (SRMs) are a heterogeneous group of tumours with varying metastatic potential. The increasing use and improving quality of abdominal imaging have led to increasingly early diagnosis of incidental SRMs that are asymptomatic and organ confined. Despite improvements in imaging and the growing use of renal mass biopsy, diagnosis of malignancy before treatment remains challenging. Management of SRMs has shifted away from radical nephrectomy, with active surveillance and nephron-sparing surgery taking over as the primary modalities of treatment. The optimal treatment strategy for SRMs continues to evolve as factors affecting short-term and long-term outcomes in this patient cohort are elucidated through studies from prospective data registries. Evidence from rapidly evolving research in biomarkers, imaging modalities, and machine learning shows promise in improving understanding of the biology and management of this patient cohort.

Partial nephrectomy for renal tumors: recommendations of the Italian Society of Urology RCC working group

INTRODUCTION

Partial nephrectomy (PN) aims to remove renal tumors while preserving renal function without affecting oncological and perioperative surgical outcomes. Aim of this paper is to summarize the current evidence on PN and to provide evidence-based recommendations on indications, surgical technique, perioperative management and postoperative surveillance of PN for renal tumors in the Italian clinical and health care system context.

EVIDENCE ACQUISITION

This review is the result of an interactive peer-reviewing process of the recent literature on PN for renal tumors carried out by an expert panel composed of members of the Italian Society of Urology (SIU) Renal Cell Carcinoma Working Group.

EVIDENCE SYNTHESIS

PN for localized renal tumors is not inferior to radical nephrectomy in terms of survival outcomes while significantly better preserving renal function. Loss of renal function after PN is influenced by medical comorbidities/preoperative renal function and surgical variables such volume of parenchyma preserved and ischemia time. Urologists should select the clamping strategy during PN based on their experience and patient-specific factors. PN can be performed with any surgical approach based on surgeon's expertise and skills. Robotic PN has the potential to expand the minimally invasive indications without interfering with oncological outcomes. The use of 3D virtual models, real time ultrasound and fluorescence tools to assess the anatomy and vascularization of renal tumors during PN may allow a more accurate preoperative planning and intraoperative guidance. Proper postoperative surveillance protocols are essential to detect tumor recurrences and assess functional outcomes.

CONCLUSIONS

PN is the standard of care for treatment of localized T1 renal tumors. Recent data supports PN also for selected T2-T3a tumors in experienced institutions. Careful preoperative planning, adequate surgical skills and volumes and appropriate postoperative management and surveillance are paramount to optimize PN oncological and functional outcomes.

Parenchymal volume analysis to assess longitudinal functional decline following partial nephrectomy

OBJECTIVE

To identify factors associated with longitudinal ipsilateral functional decline after partial nephrectomy (PN).

PATIENTS AND METHODS

Of 1140 patients managed with PN (2012-2014), 349 (31%) had imaging/serum creatinine levels pre-PN, 1-12 months post-PN (new baseline), and >3 years later necessary for inclusion. Parenchymal-volume analysis was used to determine split renal function. Patients were grouped as having significant renal comorbidity (CohortSRC : diabetes mellitus with insulin-dependence or end-organ damage, refractory hypertension, or severe pre-existing chronic kidney disease) vs not having significant renal comorbidity (CohortNoSRC ) preoperatively. Multivariable regression was used to identify predictors of annual ipsilateral parenchymal atrophy and functional decline relative to new baseline values post-PN, after the kidney had healed.

RESULTS

The median follow-up was 6.3 years with 87/226/36 patients having cold/warm/zero ischaemia. The median cold/warm ischaemia times were 32/22 min. Overall, the median tumour size was 3.0 cm. The preoperative glomerular filtration rate (GFR) and new baseline GFR (NBGFR) were 81 and 71 mL/min/1.73 m2 , respectively. After establishment of the NBGFR, the median loss of global and ipsilateral function was 0.7 and 0.4 mL/min/1.73 m2 /year, respectively, consistent with the natural ageing process. Overall, the median ipsilateral parenchymal atrophy was 1.2 cm3 /year and accounted for a median of 53% of the annual functional decline. Significant renal comorbidity, age, and warm ischaemia were independently associated with ipsilateral parenchymal atrophy (all P < 0.01). Significant renal comorbidity and ipsilateral parenchymal atrophy were independently associated with annual ipsilateral functional decline (both P < 0.01). Annual median ipsilateral parenchymal atrophy and functional decline were both significantly increased for CohortSRC compared to CohortNoSRC (2.8 vs 0.9 cm3 , P < 0.01 and 0.90 vs 0.30 mL/min/1.73 m2 /year, P < 0.01, respectively).

CONCLUSIONS

Longitudinal renal function following PN generally follows the normal ageing process. Significant renal comorbidities, age, warm ischaemia, and ipsilateral parenchymal atrophy were the most important predictors of ipsilateral functional decline following establishment of NBGFR.

Comparison of robot-assisted partial nephrectomy with soft coagulation and double-layer technique for complex and non-complex tumors

OBJECTIVES

To compare the postoperative outcomes of robot-assisted partial nephrectomy when only the inner layer is sutured (single-layer technique with soft coagulation) with those when sutures are placed in the inner and outer layers (double-layer technique) in patients with and without complex renal tumors.

METHODS

This retrospective three-institution study included 371 patients with renal tumors who underwent robot-assisted partial nephrectomy with a double-layer technique or a single-layer technique with soft coagulation. Tumors that were cT1b, completely embedded, located in the renal portal, or had a RENAL score of ≥10 were considered complex. Relevant data were collected from hospital records. Propensity score matching was performed to minimize selection bias.

RESULTS

Propensity score matching created 83 patient pairs with non-complex tumors and 32 with complex tumors. Regardless of tumor complexity, there was no significant difference in operation time, console time, warm ischemia time, positive surgical margin rate, or length of hospital stay between the double-layer and single-layer groups. Although Clavien-Dindo grade I-II urinomas not requiring intervention were significantly more common in the single-layer group regardless of tumor complexity, there was no significant between-group difference in the rate of decline in renal function or grade III-IV complications.

CONCLUSION

Single-layer suturing with soft coagulation achieves renal function and perioperative outcomes comparable to those of double-layer suturing regardless of complexity.

Transcriptional progressive patterns from mild to severe renal ischemia/reperfusion-induced kidney injury in mice

The renal ischemia/reperfusion (I/R)-induced acute kidney injury incidence after nephron-sparing surgery for localized renal tumors is 20%, but the biological determinant process of postoperative acute kidney injury remains unclear. Using Gene Expression Omnibus database (GSE192883) and several bioinformatics analyses (discrete time points analysis, gene set enrichment analysis, dynamic network biomarker analysis, etc), combined with the establishment of the I/R model for verification, we identified three progressive patterns involving five core pathways confirmed using gene set enrichment analysis and six key genes (S100a10, Pcna, Abat, Kmo, Acadm, and Adhfe1) verified using quantitative polymerase chain reaction The dynamic network biomarker (DNB) subnetwork composite index value is the highest in the 22-min ischemia group, suggesting the transcriptome expression level fluctuated sharply in this group, which means 22-min ischemia is an critical warning point. This study illustrates the core molecular progressive patterns from mild to severe I/R kidney injury, laying the foundation for precautionary biomarkers and molecular intervention targets for exploration. In addition, the safe renal artery blocking time of nephron-sparing surgery that we currently accept may not be safe anymore.

Temporal Study of Renal Volume Losses in Patients with Robotic Partial Nephrectomies

Purpose: Robotic partial nephrectomies (RPNs) by their nature are associated with renal volume loss. Our goal of this study is to examine renal volume loss over time post partial nephrectomy. Materials and Methods: Fifty patients were followed for 1-year post-RPN with two-layer renorrhaphy and the sliding clip technique. This was done with a preoperative CT scan to assess renal mass and location. Patients post-RPN were imaged at time points 3 days, 6 months, and 12 months. Results: Patient demographics were 82% men with a median (interquartile range [IQR]) age of 57 (45-67) years and all were of Japanese descent. The medians (IQR) for warm ischemia time were 18 minutes (14-22), total operative time was 181.5 minutes (169.3-218.5), and estimated blood loss was 20 mL (10-50). The tumor characteristics had a median (IQR) diameter of 2.8 cm (2.5-3.4) with a RENAL score of 7 (6-8). The renal CT showed median (IQR) volume losses at 3 days of -1% (-7.1, 1.8), at 6 months of -15.3% (-20.6, -11.2), and at 12 months of -16.3% (-19.0, -12.8). Significance was seen at the 3 days to 6 months comparison for volume loss (p < 0.0001). Mean (standard deviation) estimated glomerular filtration rate (GFR) losses were as follows: at discharge 0.5% (12.9), 1 month -6.4% (11.8), 6 months -4.6% (9.8), and 12 months -3.6% (11.9). Statistical analysis showed significance for GFR loss at the comparison between discharge to 1 and 6 months (p = 0.01, p = 0.04). Conclusion: The initial volume loss seen postsurgery from resected healthy tissue was not significant and only became relevant at longer time points, suggesting that loss could be from atrophy. Volume loss over time supports the hypothesis that suture renorrhaphy is a primary cause of volume loss when warm ischemia time is <25 minutes.

Changes in kidney function according to ischemia type during partial nephrectomy for T1a kidney cancer

To compare the postoperative estimated-glomerular-filtration-rate (eGFR) and parenchymal changes between cold ischemia and zero/selective ischemia for a T1a mass. We analyzed 104 patients who underwent open partial nephrectomy with cold ischemia (53) or zero/selective ischemia (51) for T1a between 2008 and 2018 to determine postoperative renal function changes and associated factors. Postoperative renal function was expressed as (postoperative-eGFR - preoperative-eGFR)/preoperative-eGFR × 100%. Parenchymal enhancement and thicknesses of the ipsilateral kidney as tissue changes were measured on postoperative CT to identify the correlation with the renal function change. Patients with 10% or 25% decrease in eGFR were significantly more in the cold ischemia group (p = 0.032, p = 0.006). On multivariable analysis, preoperative eGFR, ischemic type, and percent change of parenchymal thickness were identified to be significantly associated with postoperative 12 months renal function (B = - 0.367, p = 0.020; B = 6.788, p = 0.042; B = 0.797, p = 0.029). Change in parenchymal thickness was negatively correlated with changes in postoperative renal function (r = - 0.277, p = 0.012). Changes in eGFR were associated with a decrease in parenchymal thickness and the type of ischemic technique. Zero/selective ischemia during partial nephrectomy may have an advantage in preserving postoperative renal function compared to cold ischemia.

Comparison of parenchymal volume loss assessed by three-dimensional computed tomography volumetry and renal functional recovery between conventional and robot-assisted laparoscopic partial nephrectomy

OBJECTIVES

We retrospectively investigated if robot-assisted laparoscopic partial nephrectomy (RAPN) contributes to a decrease in resected parenchymal volume (RPV), an increase in postoperative parenchymal volume (PPV), and an improvement of postoperative renal function when compared with conventional laparoscopic partial nephrectomy (LPN) using a three-dimensional image analysis system.

METHODS

Patients who underwent LPN (n = 37) and RAPN (n = 66) from November 2013 to November 2018 were included in this study. All patients had a tumor diameter of 4 cm or less. Patients with an anatomical or functional single kidney were excluded. RPV and PPV were measured using SYNAPSE VINCENT®. The surgical outcomes were compared between the two groups.

RESULTS

Warm ischemic time in the RAPN group was significantly shorter than that in the LPN group (p < 0.001). The ratio of RPV to tumor volume (RPV/TV) in the RAPN group was significantly lower than that in the LPN group (p = 0.016). PPV in the RAPN group was significantly higher than that in the LPN group (p = 0.049). The decreased estimated glomerular filtration rate in the RAPN group was significantly lower than that in the LPN group on days 1, 7, 30, 90, and 180 after surgery.

CONCLUSIONS

Postoperative renal function in the RAPN group was significantly better than that in the LPN group in both the short and long term. In addition to a short warm ischemia time, the decreased RPV/TV and increased PPV may have contributed to the improvement of postoperative renal function.

Influence of robot-assisted partial nephrectomy on long-term renal function as assessed using DTPA renal scintigraphy

BACKGROUND

The long-term split renal function after robot-assisted partial nephrectomy (RAPN) is yet to be elucidate. This study aimed to assess long-term renal function RAPN, using renal scintigraphy, and to identify clinical factors related to deterioration of renal function on the affected side of the kidney.

PATIENTS AND METHODS

RAPN for small tumors was performed, and split renal function was evaluated using DTPA renal scintigraphy before and 1 year after surgery. Clinical factors (age, sex, body mass index, tumor side, presence of urinary protein, diabetes, hypertension, and dyslipidemia), perioperative factors (renal nephrectomy score [RNS], tumor diameter, overall surgery duration, console time, warm ischemic time, amount of bleeding), and renal function (estimated glomerular filtration rate (eGFR) and glomerular filtration rate (GFR) measured using scintigraphy on both the affected and contralateral kidneys) were analyzed.

RESULTS

Sixty-six patients were included in the study. The median eGFR decreased from 71.9 ml/min to 63.9 ml/min after 1 year (p<.001), accounting for a mean loss of 10.1%. In scintigraphy examination, the median GFR on the affected kidney side decreased from 41.1 ml/min to 33.7 ml/min after 1 year (p<.001), accounting for a mean loss of 16.8%. RNS was significantly associated with renal function. Among RNS factors, the N factor is　associated with renal function after RAPN.

CONCLUSION

RNS, particularly the N factor, possibly influences the long-term deterioration of renal function after RAPN.

Parenchymal Mass Loss During Partial Nephrectomy: Role of Devascularized Parenchymal Mass and Excised Parenchymal Mass and Impact on Functional Preservation

This study included 93 patients with renal masses who underwent standard partial nephrectomy or tumor enucleation. After surgery, parenchymal mass loss caused by devascularization resulted in more damage to renal function than excised parenchymal mass loss. Surgeons should seek better techniques to decrease devascularization during reconstruction.

INTRODUCTION

To evaluate the importance of devascularized parenchymal mass(DPM) and excised parenchymal mass(EPM) in functional preservation after standard partial nephrectomy(SPN).

PATIENTS AND METHODS

Forty-one patients who underwent pure tumor enucleation(TE) and 52 patients who underwent SPN with necessary data were included. As no EPM was lost in TE, the TE samples were used to estimate the degree of volume shrinkage that occurred when the measurements were performed in vivo with blood flow versus ex vivo without, and the shrinkage ratio was calculated as specimen volume divided by tumor volume in vivo. In SPN, the specimen volume comprised tumor volume plus EPM. The EPM was calculated as specimen volume divided by shrinkage ratio minus tumor volume in vivo. The DPM was defined as total ipsilateral parenchymal mass loss minus EPM. T tests, χ² test, and Mann-Whitney U tests were employed to compare clinical characteristics. Multivariate analysis was used to identify variables that correlated with glomerular filtration rate(GFR) preservation.

RESULTS

The mean sizes of devascularized and excised parenchymal masses were 13.6 cm³ and 5.2 cm³ (P = .01), which accounted for 7.8% and 3.4% of preoperative ipsilateral parenchymal mass (P = .03) in SPN, respectively. The shrinkage ratio was 0.71 and correlation coefficient was 0.965. After stepwise regression, DPM, and preoperative GFR were significantly associated with global GFR preservation.

CONCLUSION

The DPM comprises most of parenchymal mass loss after SPN and plays a more important role than EPM on functional outcomes. Surgeons should pay more attention to reducing devascularization during partial nephrectomy.

Histological and radiological evaluation of thermal denaturation depth using soft coagulation during partial nephrectomy in living pigs

OBJECTIVES

To evaluate thermal denaturation depth using soft coagulation in kidneys in vivo.

METHODS

In experiment 1, nine kidneys from five pigs were cauterized using five soft-coagulation settings at 80 W with effect 7 by VIO300D and one monopolar-coagulation setting. The surface of the kidney was cauterized over a period of 2, 5 and 10 s. The temperature change was measured at depths of 5 and 10 mm. In experiment 2, three kidneys from two pigs were excised in a semicircular shape with a diameter of 5, 10 and 20 mm without clamping the renal artery. Cauterization was carried out until hemostasis was confirmed by soft coagulation at 80 W with effect 7. After completion of the experiments, pathology examinations of the kidneys were carried out.

RESULTS

Experiment 1 showed that with proper saline dripping, denaturation spread with increased cauterization time, reaching a depth of 4 mm at 10 s with or without clamps. The depth remained at 2-3 mm at 10 s in the absence or excess of saline. The temperature increased by 15.6°C at a depth of 5 mm and 8.8°C at 10 mm. In experiment 2, the depth was 4.6 mm from the incision surface regardless of the cauterization time or excision size.

CONCLUSIONS

These findings suggest that soft coagulation can be useful for preserving renal function and reducing complications in partial nephrectomy.

Open Partial Nephrectomy vs. Robot-assisted Partial Nephrectomy for a Renal Tumor Larger than 4 cm: a Propensity Score Matching Analysis

BACKGROUND

To compare open partial nephrectomy (OPN) and robot-assisted partial nephrectomy (RAPN) in the management of renal tumors larger than 4 cm.

METHODS

Clinical records of 220 patients who underwent OPN or RAPN for a single renal tumor ≥ 4.0 cm with a normal contralateral kidney were reviewed. After determining the propensity score, surgical parameters, functional outcomes, and oncological outcomes were compared between OPN (n = 67) and RAPN (n = 67) groups of patients.

RESULTS

The RAPN group had longer operation time (149.0 min vs. 173.3 min, P = 0.030) and longer ischemic time (20.3 min vs. 29.4 min, P = 0.001), but shorter hospital stay (8.2 days vs 6.0 days, P = 0.001) than the OPN group. Estimated blood loss (P = 0.053), pain visual analog score at 1 day postoperatively (P = 0.194), and complications of grade III or higher (P = 0.403) were similar between OPN and RAPN groups. There was no radical conversion or positive surgical margin in either group. Mean change in 6-month estimated glomerular filtration rate was significantly better in the RAPN group (-8.2 vs. -3.1, P = 0.027). There was no statistical difference in recurrence-free survival (P = 0.970) or cancer-specific survival (P = 0.345) between the two groups.

CONCLUSION

RAPN is a safe and feasible surgical modality comparable to OPN for managing renal tumors larger than 4 cm in terms of surgical, functional, and oncological outcomes.

Spatiotemporal ATP Dynamics during AKI Predict Renal Prognosis

BACKGROUND

Depletion of ATP in renal tubular cells plays the central role in the pathogenesis of kidney diseases. Nevertheless, inability to visualize spatiotemporal in vivo ATP distribution and dynamics has hindered further analysis.

METHODS

A novel mouse line systemically expressing an ATP biosensor (an ATP synthase subunit and two fluorophores) revealed spatiotemporal ATP dynamics at single-cell resolution during warm and cold ischemic reperfusion (IR) with two-photon microscopy. This experimental system enabled quantification of fibrosis 2 weeks after IR and assessment of the relationship between the ATP recovery in acute phase and fibrosis in chronic phase.

RESULTS

Upon ischemia induction, the ATP levels of proximal tubule (PT) cells decreased to the nadir within a few minutes, whereas those of distal tubule (DT) cells decreased gradually up to 1 hour. Upon reperfusion, the recovery rate of ATP in PTs was slower with longer ischemia. In stark contrast, ATP in DTs was quickly rebounded irrespective of ischemia duration. Morphologic changes of mitochondria in the acute phase support the observation of different ATP dynamics in the two segments. Furthermore, slow and incomplete ATP recovery of PTs in the acute phase inversely correlated with fibrosis in the chronic phase. Ischemia under conditions of hypothermia resulted in more rapid and complete ATP recovery with less fibrosis, providing a proof of concept for use of hypothermia to protect kidney tissues.

CONCLUSIONS

Visualizing spatiotemporal ATP dynamics during IR injury revealed higher sensitivity of PT cells to ischemia compared with DT cells in terms of energy metabolism. The ATP dynamics of PTs in AKI might provide prognostic information.

Nephrometry Scores: Can Preoperative Assessment of Sectional Imaging Really Mirror Intraoperative Renal Tumor Anatomy?

INTRODUCTION

To compare RENAL, preoperative aspects and dimensions used for an anatomical (PADUA) classification, and Mayo Adhesive Probability (MAP) scores with the respective intraoperative findings and surgeon's assessment in predicting surgical outcome of patients undergoing partial nephrectomy.

METHODS

Data of 150 eligible patients treated at the University Medical Center Mannheim between 2016 and 2018 were analyzed. Tumors were radiologically and intraoperatively assessed by PADUA, RENAL, and MAP scores and surgeon's assessment. Correlations and regression models were created to predict ischemia time (IT), major complications, and Trifecta (negative surgical margin, IT < 25 min, and absence of major complications).

RESULTS

There were strong correlations between radiological and intraoperative RENAL (r = 0.68; p < 0.001) and PADUA scores (r = 0.72; p < 0.001). Radiological RENAL, PADUA, and MAP scores and surgeon's assessment were independent predictors of Trifecta (OR = 0.71, p = 0.015; OR = 0.77, p = 0.035; OR = 0.65, p = 0.012; OR = 0.40, p = 0.005, respectively). IT showed significant associations with radiological RENAL, PADUA, and surgeon's assessment (OR = 1.41, p = 0.033; OR = 1.34, p = 0.044; OR = 3.04, p = 0.003, respectively). MAP score proved as only independent predictor of major complications (OR = 2.12, p = 0.002).

CONCLUSION

Radiologically and intraoperatively assessed scores correlated well with each other. Intraoperative nephrometry did not outperform radiological scores in predicting outcome confirming the value of the existing systems. MAP score correlates well with surgeon's assessment of perirenal fat and major complications underlining the importance of perirenal fat characteristics.

Effectiveness and safety of partial nephrectomy-no ischemia vs. warm ischemia: Systematic review and meta-analysis

PURPOSE

This study aimed to determine the effectiveness and safety of partial nephrectomy (PN) without ischemia compared with PN with warm ischemia for reducing the deterioration in renal function in patients with cT1 renal tumors.

MATERIALS AND METHODS

We conducted a systematic review that included patients over 18 years of age who underwent PN with or without warm ischemia for cT1 renal tumors. The primary outcome was impaired renal function. A search strategy was performed in MEDLINE, EMBASE, LILACS, CENTRAL, the article reference lists, and the unpublished literature to reach saturation of the information. We assessed the risk of bias with the methodological index for nonrandomized studies (MINORS) tool, and we performed a meta-analysis according to the type of variable.

RESULTS

We found a total of 5,682 articles, of which 14 met the inclusion criteria. Seven studies evaluated renal function, identifying a difference in means (MD) of 3.50 (95% confidence interval [CI], 1.16 to 5.83), favoring no ischemia. We did not find any significant differences regarding intraoperative bleeding or operative time (MD, 55 mL; 95% CI, -33.16 to 144.08; and MD, 1.87; 95% CI, -20.47 to 24.21; respectively).

CONCLUSIONS

In this study, PN without ischemia showed a decrease in deterioration of the estimated glomerular filtration rate compared with warm ischemia.

Cold Versus Warm Ischemia Robot-Assisted Partial Nephrectomy: Comparison of Functional Outcomes in Propensity-Score Matched "At Risk" Patients

OBJECTIVES

To compare functional outcomes of warm ischemia RPN (wRPN) to cold ischemia RPN (cRPN) in "at risk" patients.

MATERIALS AND METHODS

Retrospective review of institutional database queried for all patients who underwent cRPN/wRPN (January 2007-December 2016). For the study purpose, patients with solitary kidney and/or history of partial nephrectomy and/or multiple tumors and/or preoperative estimated Glomerular Filtration Rate (eGFR) <60 mL/minute were extracted. To reduce inherent biases, groups were matched on key variables related to renal function through a greedy matching algorithm with no replacement. Renal functional outcomes were evaluated by eGFR drops at 1-3 days and at 1, 3, 6, and 12 months postoperatively. A linear mixed effects model was used to assess eGFR at each follow-up who received either cRPN or wRPN. Follow-up was treated as a factor variable to account for nonlinear time trends. Contrast analysis was used to compare cRPN vs wRPN groups at each follow-up, using Sidak-Holm p-value adjustments for multiple comparisons.

RESULTS

Out of 19 cRPN patients and 279 wRPN patients, 14 cRPN patients were finally matched 1:1 with no replacement to 14 wRPN. There was no significant difference in preoperative eGFR for matched patients undergoing cRPN vs wRPN. Since the first postoperative day, cRPN patients had higher eGFR. The difference was statistically significant since the third month postoperatively (mean difference = 18.201, 95% confidence interval [CI]: 1.930-34.472) and remained at both the sixth month (mean difference = 18.839, 95% CI: 2.568-35.109) and the 12th month (mean difference = 21.277, 95% CI: 5.006-37.547) follow-up.

CONCLUSIONS

Accounting for unmodifiable and modifiable factors, in a cohort of highly selected patients "at risk" for postoperative significant decline in renal function after RPN, renal functional outcomes appear to be superior with cold ischemia technique.

The correlation between affected renal function and affected renal residual volume: A retrospective outcome of laparoscopic nephron-sparing partial nephrectomy with segmental renal artery blocking-up for localized renal tumors

Laparoscopic nephron-sparing partial nephrectomy with segmental renal artery blocking (SRPN) has been widely used in the treatment of localized renal tumors. However, the impact of ischemia-reperfusion injury (IRI) during SRPN remains controversial. This study aims to evaluate the correlation between affected renal function and affected renal volume after SRPN for localized renal tumor treatment, explore the effect of IRI on renal function after SRPN.A total of 39 patients who underwent SRPN for localized renal tumor from June 2009 to April 2012 were reviewed. These patients were followed-up for 5 years. The preoperative affected renal glomerular filtration rate (aGFRpre), postoperative affected renal glomerular filtration rate (aGFRpost), preoperative affected renal volume (aVolpre), and postoperative affected renal volume (aVolpost) were collected during the follow-up period. The correlation between aGFRpost/aGFRpre and aVolpost/aVolpre was compared.A total of 33 patients were successfully followed up. After 3, 6, 12, 24, and 60 months, aGFRpost was 34.6 ± 4.6, 34.7 ± 4.8, 34.9 ± 4.4, 35.1 ± 4.4, and 35.2 ± 4.2 mL/min. The correlation coefficients between aGFRpost/aGFRpre and aVolpost/aVolpre were 0.659 (P = .000), 0.667 (P = .000), 0.663 (P = .000), 0.629 (P = .000), and 0.604 (P = .000), respectively. The limitation of this study was the small cohort size.For the localized renal tumor, aGFRpost was associated with aVolpost, but was not associated with intraoperative factors, such as the time of clamping of the affected segmental renal artery. As a part of nephrons, the resected tumor tissue caused the lack of inherent nephrons, resulting in the loss of renal function. More nephrons should be maintained before resecting the tumor completely during SRPN.Trial registration: ChiCTR-RRC-17011418.

Optimising renal cancer patients for nephron-sparing surgery: a review of pre-operative considerations and peri-operative techniques for partial nephrectomy

Nonmodifiable factors including pre-operative renal function and amount of healthy renal tissue preserved are the most important predictive factors that determine renal function after partial nephrectomy. Ischaemia time is an important modifiable risk factor and cold ischaemia time should be used if longer ischaemia time is anticipated. New techniques may have a role in maximising postoperative kidney function, but more robust studies are required to understand their potential benefits and risks.

Comparison of Renal Function between Robot-Assisted and Open Partial Nephrectomy as Determined by Tc 99m-DTPA Renal Scintigraphy

We compared postoperative renal function impairment between patients undergoing robot-assisted partial nephrectomy (RAPN) and those undergoing open partial nephrectomy (OPN) by using Tc-99m diethylenetriaminepentaacetic acid (DTPA) renal scintigraphy. Patients who underwent partial nephrectomy by a single surgeon between 2007 and 2013 were eligible and were matched by propensity score, based on age, tumor size, exophytic properties of tumor, and location relative to the polar lines. Of the 403 patients who underwent partial nephrectomy, 114 (28%) underwent RAPN and 289 (72%) underwent OPN. Mean follow-up duration was 35.2 months. Following propensity matching, there were no significant differences between the two groups in tumor exophytic properties (P = 0.818) or nephrometry score (P = 0.527). Renal ischemic time (24.4 minutes vs. 17.8 minutes, P < 0.001) was significantly longer in the RAPN group than in the OPN group, while the other characteristics were similar. Multivariate analysis showed that greater preoperative renal unit function (P = 0.011) and nephrometry score (P = 0.041) were independently correlated with a reduction in glomerular filtration rate. The operative method did not correlate with renal function impairment (P = 0.704). Postoperative renal function impairment was similar between patients who underwent OPN and those who underwent RAPN, despite RAPN having a longer ischemic time.

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.

The learning curve and factors affecting warm ischemia time during robot-assisted partial nephrectomy

Introduction:

The learning curve for robotic partial nephrectomy was investigated for an experienced laparoscopic surgeon and factors associated with warm ischemia time (WIT) were assessed.

Materials and Methods:

Between 2007 and 2014, one surgeon completed 171 procedures. Operative time, blood loss, complications and ischemia time were examined to determine the learning curve. The learning curve was defined as the number of procedures needed to reach the targeted goal for WIT, which most recently was 20 min. Statistical analyses including multivariable regression analysis and matching were performed.

Results:

Comparing the first 30 to the last 30 patients, mean ischemia time (23.0–15.2 min, P < 0.01) decreased while tumor size (2.4–3.4 cm, P = 0.02) and nephrometry score (5.9–7.0, P = 0.02) increased. Body mass index (P = 0.87), age (P = 0.38), complication rate (P = 0.16), operating time (P = 0.78) and estimated blood loss (P = 0.98) did not change. Decreases in ischemia time corresponded with revised goals in 2011 and early vascular unclamping with the omission of cortical renorrhaphy in selected patients. A multivariable analysis found nephrometry score, tumor diameter, cortical renorrhaphy and year of surgery to be significant predictors of WIT.

Conclusions:

Adoption of robotic assistance for a surgeon experienced with laparoscopic surgery was associated with low complication rates even during the initial cases of robot-assisted partial nephrectomy. Ischemia time decreased while no significant changes in blood loss, operating time or complications were seen. The largest decrease in ischemia time was associated with adopting evidence-based goals and new techniques, and was not felt to be related to a learning curve.

Use of biological Glue (Bioglue®) in laparoscopic partial nephrectomy: a study in pigs

Introduction

Partial nephrectomy is the standard of care for localized renal tumors. However, bleeding and warm ischemia time are still controversial when laparoscopic surgeries are carried out. Herein, we aim to compare the outcomes from laparoscopic partial nephrectomy with and without the use of biological glue with purified bovine albumin and glutaraldehyde (BioGlue®).

Materials and Methods

Twenty-four kidneys of 12 pigs were used in this study. A pre-determined lower pole segment was resected (3 cm x 1 cm) and one of two different hemostatic techniques was performed. In one kidney, hemostatic “U suture” (poliglecaprone 3.0) was performed and in the contra-lateral kidney, only the biological glue was applied. Data recorded was comprised of warm ischemia time (seconds) and estimated blood loss (mL) for each procedure. In cases of bleeding after glue administration, a complementary suture was done.

Results

Mean warm ischemia time was 492.9±113.1 (351-665) seconds and 746±185.3 (409-1125) seconds for biological glue and suture groups, respectively. There was a positive significant difference in terms of warm ischemia favoring the biological glue group over the suture group (p<0.001). Mean blood loss was 39.4 (0-115) mL for the biological glue group and 39.1 (5-120) mL for the suture group (p=0.62).

Conclusion

Biological glue is an important tool for laparoscopic partial nephrectomies. It is effective for hemostatic control in selected cases, and it can be used in combination with the traditional suture techniques.

Renal functional outcomes after surgery for renal cortical tumors

Historically, radical nephrectomy represented the gold standard for the treatment of small (≤ 4cm) as well as larger renal masses. Recently, for small renal masses, the risk of ensuing chronic kidney disease and end stage renal disease has largely favored nephron-sparing surgical techniques, mainly partial nephrectomy. In this review, we surveyed the literature on renal functional outcomes after partial nephrectomy for renal tumors. The largest randomized control trial comparing radical and partial nephrectomy failed to show a survival benefit for partial nephrectomy. With regards to overall survival, surgically induced chronic kidney disease (GFR < 60 ml/min/ 1.73m²) caused by nephrectomy might not be as deleterious as medically induced chronic kidney disease. In evaluating patients who underwent donor nephrectomy, transplant literature further validates that surgically induced reductions in GFR may not affect patient survival, unlike medically induced GFR declines. Yet, because patients who present with a renal mass tend to be elderly with multiple comorbidities, many develop a mixed picture of medically, and surgically-induced renal disease after extirpative renal surgery. In this population, we believe that nephron sparing surgery optimizes oncological control while protecting renal function.

Feasibility of omitting cortical renorrhaphy during robot-assisted partial nephrectomy: a matched analysis

BACKGROUND AND PURPOSE

To assess the safety of omitting cortical renorrhaphy during robot-assisted partial nephrectomy and measure preliminary functional outcomes.

PATIENTS AND METHODS

Fifteen robot-assisted partial nephrectomies were performed with a running, base-layer suture for the collecting system and vessel hemostasis but without cortical renorrhaphy. The nonrenorrhaphy group was matched 1:2 by R.E.N.A.L. nephrometry score to a running, sliding-clip cortical renorrhaphy group retrospectively. Intraoperative blood loss, urine leaks, postoperative bleeds, and functional outcomes were evaluated. Predictors of %volume loss were evaluated using multivariable regression.

RESULTS

No differences were seen between renorrhaphy and nonrenorrhaphy in sex (P=0.53), age (P=0.14), body mass index (P=0.08), Charlson score (P=0.44), tumor diameter (P=0.55), nephrometry score (P=0.77), preoperative glomerular filtration rate (GFR, P=0.63), or the amount of resected healthy kidney margin (P=0.21). Warm ischemia time was less for the nonrenorrhaphy group (P<0.002). One pseudoaneurysm necessitating embolization (1/30=3%) was seen in the renorrhaphy group compared with none in the nonrenorrhaphy group. No urine leaks occurred in either group. The median %GFR loss was 8.8% for renorrhaphy and 4.4% for nonrenorrhaphy (P=0.14) at a median follow-up of 4.1 months. The median %volume loss was 17 cm(3) for renorrhaphy and 9 cm(3) for nonrenorrhaphy (P=0.003). In a multivariable model, both cortical renorrhaphy (P=0.004) and tumor diameter (P=0.004) were predictors of %volume loss.

CONCLUSION

Omission of cortical renorrhaphy appears feasible with no urine leaks or bleeding complications observed. The percent renal volume loss was improved by omission of cortical renorrhaphy. Reconstruction technique is important to control for when studying renal function after partial nephrectomy.

A novel robotic system for single-port urologic surgery: first clinical investigation

BACKGROUND

The idea of performing a laparoscopic procedure through a single abdominal incision was conceived with the aim of expediting postoperative recovery.

OBJECTIVE

To determine the clinical feasibility and safety of single-port urologic procedures by using a novel robotic surgical system.

DESIGN, SETTING, AND PARTICIPANTS

This was a prospective institutional review board-approved, Innovation, Development, Exploration, Assessment, Long-term Study (IDEAL) phase 1 study. After enrollment, patients underwent a major urologic robotic single-port procedure over a 3-wk period in July 2010. The patients were followed for 3 yr postoperatively.

INTERVENTION

Different types of urologic surgeries were performed using the da Vinci SP Surgical System. This system is intended to provide the same core clinical capabilities as the existing multiport da Vinci system, except that three articulating endoscopic instruments and an articulating endoscopic camera are inserted into the patient through a single robotic port.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The main outcomes were the technical feasibility of the procedures (as measured by the rate of conversions) and the safety of the procedures (as measured by the incidence of perioperative complications). Secondary end points consisted of evaluating other key surgical perioperative outcomes as well as midterm functional and oncologic outcomes.

RESULTS AND LIMITATIONS

A total of 19 patients were enrolled in the study. Eleven of them underwent radical prostatectomy; eight subjects underwent nephrectomy procedures (partial nephrectomy, four; radical nephrectomy, two; and simple nephrectomy, two). There were no conversions to alternative surgical approaches. Overall, two major (Clavien grade 3b) postoperative complications were observed in the radical prostatectomy group and none in the nephrectomy group. At 1-yr follow-up, one radical prostatectomy patient experienced biochemical recurrence, which was successfully treated with salvage radiation therapy. The median warm ischemia time for three of the partial nephrectomies was 38 min. At 3-yr follow-up all patients presented a preserved renal function; none had tumor recurrence. Study limitations include the small sample and the lack of a control group.

CONCLUSIONS

We describe the first clinical application of a novel robotic platform specifically designed for single-port urologic surgery. Major urologic procedures were successfully completed without conversions. Further assessment is warranted to corroborate these promising findings.

PATIENT SUMMARY

A novel purpose-built robotic system enables surgeons to perform safely and effectively a variety of major urologic procedures through a single small abdominal incision.

TRIAL REGISTRATION

The study was registered on www.ClinicalTrials.gov (NCT02136121).

The impact of non-hilar clamping open partial technique performed for the treatment of patients with small renal masses with lower R.E.N.A.L. nephrometry scores on renal functions during the early postoperative period

OBJECTIVE

Herein, the impact of off-clamp open partial nephrectomy on early postoperative period renal functions were evaluated in patients with low RENAL nephrometry scoring small renal masses.

MATERIAL AND METHODS

Twenty-three patients (12 women, and 11 men) who had undergone non-hilar clamping open partial nephrectomy in our clinic between the years 2010, and 2013 were retrospectively evaluated. Mean age, body mass index (BMI), operative time, blood loss, renal nephrometry score, mean hospital stay, pre-, and postoperative serum creatinine (Cr), and glomerular filtration rate (GFR) of the patients were assessed.

RESULTS

Mean age, BMI, tumor size, and preoperative renal nephrometry scores were 56.09±10.49 years (36-70 yrs), 24.81±2.44 kg/m(2), 3.68±1.125 cm, and 6.41±1.77 pts, respectively. Mean operative time, intraoperative blood loss, and hospital stay were detected as 139.14±33.60 min, 274.9±77.02 mL, and 4.27±1.12 days, respectively. Preoperative mean serum Cr, and GFR levels were 0.804±0.216 mg/dL, and 93.97±25.83 mL/min/1.73 m(2), respectively. Postoperative 1. day mean serum Cr, and GFR levels were 0.896±0.25 mg/dL, and 85.94±28.85 mL/min/1,73 m(2), while corresponding 3. month-values were 0.81±0.205 mg/dL, and 93.59±21.00 mL/dk/1.73 m(2), respectively. A statistically significant difference was not found between preoperative, and postoperative 3. month- serum Cr, and GFR levels. However, postoperative 3. month-serum Cr, and GFR levels were lower than corresponding values estimated on postoperative 1. day (p<0.016).

CONCLUSION

One of the important considerations in partial nephrectomy is to preserve renal functions. Therefore, non-hilar clamping open partial nephrectomy should be taken into consideration for surgeons unexperienced especially in laparoscopic surgery with its lower morbidity, and complication rates.

Long-term renal functional outcomes of minimally invasive partial nephrectomy for renal cell carcinoma

OBJECTIVE

Preservation of renal function is the major benefit of partial over radical nephrectomy. We evaluated patients undergoing minimally invasive partial nephrectomy (MIPN) to better understand factors predicting long-term renal function.

METHODS

We identified 358 patients who underwent MIPN for confirmed renal cell carcinoma between 1998 and 2011 with a serum creatinine level at least 1 year postoperatively. Exposure variables included demographic, clinical, and perioperative information. The primary outcome was clinically significant progression of chronic kidney disease (CKD) class, defined as estimated glomerular filtration rate (eGFR) decreasing from >60 to<60, from 30 to 60 to <30, or from 15 to 30 to<15. Bivariate and multivariate analyses were performed.

RESULTS

Median follow-up was 39 months. Only 7 patients had a solitary kidney. A total of 47 patients (13%) had CKD class progression. The estimates for remaining free of CKD class progression at 5, 7, and 10 years were 86.98%, 75.45%, and 53.54%, respectively. On multivariate analysis, lower preoperative eGFR (odds ratio [OR] = 0.97, 95% CI: 0.96-0.98), larger tumor size (OR = 1.22, 95% CI: 1.01-1.48), and longer ischemia time (OR = 1.03, 95% CI: 1.01-1.05) were associated with CKD class progression.

CONCLUSIONS

Clinically significant progression of CKD occurs in a minority of patients 5 years after MIPN, but in almost one-half, it occurs 10 years after surgery. Lower preoperative eGFR and larger tumor size are associated with greater incidence of CKD progression. Longer ischemia time, even when most patients had 2 kidneys and when controlling for other factors, nonetheless increased the risk of CKD progression, although this may be a marker of other unmeasured variables.

Chronic renal insufficiency after partial nephrectomy for T1b tumors

PURPOSE OF REVIEW

Partial nephrectomy for larger kidney tumors (T1b) has gained widespread acceptance in most academic institutions, with similar oncologic outcomes to radical nephrectomy. This review focuses on the factors that affect renal function after partial nephrectomy, and presents current information about the relative importance of each factor as well as chronic kidney disease (CKD) after renal surgery.

RECENT FINDINGS

CKD occurs over the long term in a significant percentage of patients following partial nephrectomy. The interaction of different factors including baseline kidney function (influenced by age and medical comorbidity), amount of preserved renal parenchyma (influenced by surgical technique), and ischemia time (warm or cold) determines the ultimate functional outcome. De-novo CKD resulting from surgery in previously healthy individuals may not place these patients at increased risk of progression or mortality.

SUMMARY

Urologists continue to strive towards improved kidney function after partial nephrectomy, particularly for larger tumors. Careful identification of factors involved in functional outcome, and optimization of modifiable factors, will remain at the forefront of efforts to minimize renal functional loss after partial nephrectomy.