Longterm changes in creatinine clearance after laparoscopic renal surgery

Impact of learning curve on perioperative outcomes of off-clamp minimally invasive partial nephrectomy: propensity score matched comparison of outcomes between training versus expert series

BACKGROUND

Off-clamp robotic partial nephrectomy (Off C-RPN) is a challenging technique, hard to teach since bleeding control is not easily reproducible in training settings. We compared perioperative outcomes of two propensity score matched (PSM) cohorts of patients undergone Off C-RPN by either a training or an expert surgeon in the same Institution.

METHODS

The prospectively maintained "renal cancer" database was queried for "off-clamp," "robotic," "partial nephrectomy" performed between January 2017 and June 2018. Achievement of main outcomes along the learning curve of training surgeon was assessed with logistic regression and Lowess analysis. A 1:1 PSM analysis generated two populations homogeneous for demographics, ASA score, tumor size, nephrometry score, baseline hemoglobin and estimated glomerular filtration rate (eGFR). Multiple tumors, and imperative indications were excluded. Categorical and continuous variables were compared by χ² and t-test.

RESULTS

Overall, 111 were treated by the expert, 51 by the training surgeon, respectively. Training surgeon experienced a significant decrease of console time (P=0.01). Patients treated by the expert surgeon had significantly larger tumors, higher PADUA and ASA scores (all P≤0.04). After applying the PSM, two cohorts of 29 patients, homogeneous for all baseline demographic and clinical variables (all P≥0.34) were selected. Hilar clamping was never necessary. Hospital stay, hemoglobin and eGFR at discharge, complication and positive surgical margins rates were comparable between the two cohorts (all P≥0.15).

CONCLUSIONS

Our results proved that the impact of learning curve on outcomes of Off C-RPN is negligible after completion of a proper training in minimally invasive surgery.

Comparison of Intermittent Versus Continuous Ischemia During Laparoscopic Partial Nephrectomy in a Porcine Model

Renal ischemic time is one of the most variable risk factors in partial nephrectomy (PN). Our purpose was to investigate if intermittent ischemia could decrease renal impairment in the process of PN in porcine model and explore the feasibility of this surgical procedure in nephrectomy. A kidney ischemia-reperfusion injury model was successfully established in six pigs under laparoscopic surgery. One kidney of each pig was continuously ischemic, and intermittent ischemia was administered to the kidney of another side. Laparoscopic renal artery occlusion was applied to each kidney for 120 minutes. Intermittent ischemia was 15/3 minutes of cycles (ischemia for 15 minutes and reperfusion for 3 minutes). Microdialysis technique, immunohistochemistry, and histopathology were used to evaluate the extent of renal function injures. The concentration of glycerol in intermittently ischemic group was significantly lower than that in continuously ischemic group (F = 19.06, p = 0.001). NGAL and BCL-2 immunostaining of the renal tubular epithelial cell in the intermittent ischemia kidneys was significantly reduced compared with that in the continuously ischemic kidneys (F = 5.51, p = 0.041; F = 13.53, p = 0.004). Our study has shown that intermittent ischemia is a possibly effective and practicable surgical process for reducing renal ischemic damage in porcine model nephrectomy.

How a Donor Nephrectomy Population Can Help Give Perspective to the Effects of Renal Parenchymal Preservation During Partial Nephrectomy

Introduction: Volume of renal parenchymal loss is known to affect postoperative renal function after partial nephrectomy (PN). We utilize a novel comparison using donor nephrectomy (DN) patients to demonstrate the primary effect parenchymal volume loss plays on postoperative renal function following PN. Materials and Methods: Records of 250 living donor (DN) and 118 PN patients were retrospectively reviewed. Baseline characteristics and preoperative estimated glomerular filtration rate (eGFR)s were recorded. Percent changes in eGFR and incidences of surgically induced chronic kidney disease (CKD-S) in short, intermediate, and long-term postoperative periods were compared. Univariate and multivariate analyses of prognostic factors for development of CKD-S were performed. The PN group was further divided into subgroups with different lengths of warm ischemia time (WIT) and compared with DN patients. Results: At baseline, DN patients were younger, less likely to be male, had lower body mass index, lower American Society of Anesthesiologists, and higher preoperative eGFR (all p < 0.001). At hospital discharge, intermediate follow-up, and latest follow-up, renal function changes in DN and PN groups were -40.5% vs. -3.6%, -34.1% vs. -5.5%, and -33.2% vs. -4.4%, respectively (all p < 0.001). More DN than PN patients developed CKD-S (p < 0.001). DN was a significant risk factor for the development of chronic kidney disease on univariate and multivariate analyses (p < 0.001). On subgroup analysis, both subgroups with WIT 1 to 30 minutes and 31 to 60 minutes had less renal function decline at all time points compared with DN (p < 0.001). Conclusions: Volume of renal parenchyma retained is the dominant driver of postoperative renal function after nephrectomy, compared with all other factors. Surgeons should minimize parenchymal loss during PN to optimize postoperative renal function.

Partial nephrectomy versus ablative techniques for small renal masses: a systematic review and network meta-analysis

PURPOSE

To compare partial nephrectomy (PN), radiofrequency ablation (RFA), cryoablation (CRA) and microwave ablation (MWA) regarding oncologic, perioperative and functional outcomes.

MATERIAL AND METHODS

The MEDLINE, EMBASE and COCHRANE libraries were searched for studies comparing PN, RFA, CRA or MWA and reporting on any-cause or cancer-specific mortality, local recurrence, complications or renal function. Network meta-analyses were performed.

RESULTS

Forty-seven studies with 24,077 patients were included. Patients receiving RFA, CRA or MWA were older and had more comorbidities compared with PN. All-cause mortality was higher for CRA and RFA compared with PN (incidence rate ratio IRR = 2.58, IRR = 2.58, p < 0.001, respectively). No significant differences in cancer-specific mortality were evident. Local recurrence was higher for CRA, RFA and MWA compared with PN (IRR = 4.13, IRR = 1.79, IRR = 2.52, p < 0.05 respectively). A decline in renal function was less pronounced after RFA versus PN, CRA and MWA (mean difference in GFR MD = 6.49; MD = 5.82; MD = 10.89, p < 0.05 respectively).

CONCLUSION

Higher overall survival and local control of PN compared with ablative therapies did not translate into significantly better cancer-specific mortality. Most studies carried a high risk of bias by selecting younger and healthier patients for PN, which may drive superior survival and local control. Physicians should be aware of the lack of high-quality evidence and the potential benefits of ablative techniques for certain patients, including a superior complication profile and renal function preservation.

KEY POINTS

• Patients selected for ablation of small renal masses are older and have more comorbidities compared with those undergoing partial nephrectomy. • Partial nephrectomy yields lower all-cause mortality, which is probably biased by patient selection and does not translate into prolonged cancer-free survival. • The decline of renal function is smallest after radiofrequency ablation for small renal masses.

Off-clamp partial nephrectomy has a positive impact on short- and long-term renal function: a systematic review and meta-analysis

Background

Ongoing efforts are focused on shortening ischemia intervals as much as possible during partial nephrectomy to preserve renal function. Off-clamp partial nephrectomy (off-PN) has been a common strategy for to avoid ischemia in small renal tumors. Although studies comparing the advantages between off-PN with conventional on-clamp partial nephrectomy (on-PN) have been reported, the impact on short- and especially long-term renal function of the two surgical methods has not been discussed seriously and remained unclear. Our purpose is to evaluate the impact on short- (within postoperative 3 months) and long-term (postoperative 6 months or longer) renal function of off-PN compared with that of on-PN.

Methods

We comprehensively searched databases, including PubMed, EMBASE, and the Cochrane Library, without restrictions on language or region. A systematic review and cumulative meta-analysis of the included studies were performed to assess the impact of the two techniques on short- and long-term renal function.

Results

A total of 23 retrospective studies and 2 prospective cohort studies were included. The pooled postoperative short-term decrease of estimated glomerular filtration rate (eGFR) was significantly less in the off-PN group (weighted mean difference [WMD]: 4.81 ml/min/1.73 m²; 95% confidence interval [CI]: 3.53 to 6.08; p < 0.00001). The short-term increase in creatinine (Cr) level in the on-PN group was also significant (WMD: − 0.05 mg/dl; 95%CI: − 0.09 to − 0.00; p = 0.04). Significant differences between groups was observed for the long-term change and percent (%) change of eGFR (p = 0.04 and p < 0.00001, respectively) but not for long-term Cr change (p = 0.40). The postoperative short-term eGFR and Cr levels, but not the postoperative long-term eGFR, differed significantly between the two groups. The pooled odds ratios for acute renal failure and postoperative progress to chronic kidney disease (stage≥3) in the off-PN group were found to be 0.25 (p = 0.003) and 0.73 (p = 0.34), respectively, compared with the on-PN group.

Conclusions

Off-PN exerts a positive impact on the short- and long-term renal function compared with conventional on-PN. Given the inherent limitations of our included studies, large-volume and well-designed RCTS with extensive follow up are needed to confirm and update the conclusion of this analysis.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-0993-3) contains supplementary material, which is available to authorized users.

[Ablative therapy in kidney cancer: Oncological, functional, perioperative outcomes and cost]

INTRODUCTION

The incidence of kidney cancer has increased significantly over the past few decades presumably due to the increased use of imaging. The aim of this article is to describe contemporary outcomes of ablative therapy and to compare them to other therapeutic options in terms of oncological, functional, perioperative outcomes and cost.

MATERIAL AND METHODS

We searched MEDLINE^®, Embase^®, using (MeSH) words; from January 2005 through May 2017, and we looked for all the studies. Investigators graded the strength of evidence in terms of methodology, language and relevance.

RESULTS

Ninety-one articles were analyzed. We described the outcomes of ablative therapy in relation to the energy used and the approach, and compared these outcomes to the other therapeutic options in terms of oncological, functional and perioperative outcomes. We analyzed these studies in order to search for predictive factors influencing the results of ablative therapy. We also analyzed the economic burden of small renal tumor management.

CONCLUSION

The strength of evidence is based almost entirely on retrospective studies and is susceptible to the inherent limitations of this study design. Although, the evidence was low among studies, our revue showed that, in elderly patients treated with ablative therapy for cT1a tumors, the cancer-specific survival was comparable to partial nephrectomy with differences in overall survival that are explained by competing risks of death in the old population. Considering the functional results, the renal function preservation seems to be comparable between the 2 groups while the perioperative morbidity is higher in the partial nephrectomy group. The evidence base medicine at this time cannot support the extension of the indications of ablative therapy beyond the actual implementations.

Renal Functional Outcomes after Surgery, Ablation, and Active Surveillance of Localized Renal Tumors: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

Management strategies for localized renal masses suspicious for renal cell carcinoma include radical nephrectomy, partial nephrectomy, thermal ablation, and active surveillance. Given favorable survival outcomes across strategies, renal preservation is often of paramount concern. To inform clinical decision making, we performed a systematic review and meta-analysis of studies comparing renal functional outcomes for radical nephrectomy, partial nephrectomy, thermal ablation, and active surveillance.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

We searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials from January 1, 1997 to May 1, 2015 to identify comparative studies reporting renal functional outcomes. Meta-analyses were performed for change in eGFR, incidence of CKD, and AKI.

RESULTS

We found 58 articles reporting on relevant renal functional outcomes. Meta-analyses showed that final eGFR fell 10.5 ml/min per 1.73 m2 lower for radical nephrectomy compared with partial nephrectomy and indicated higher risk of CKD stage 3 or worse (relative risk, 2.56; 95% confidence interval, 1.97 to 3.32) and ESRD for radical nephrectomy compared with partial nephrectomy. Overall risk of AKI was similar for radical nephrectomy and partial nephrectomy, but studies suggested higher risk for radical nephrectomy among T1a tumors (relative risk, 1.37; 95% confidence interval, 1.13 to 1.66). In general, similar findings of worse renal function for radical nephrectomy compared with thermal ablation and active surveillance were observed. No differences in renal functional outcomes were observed for partial nephrectomy versus thermal ablation. The overall rate of ESRD was low among all management strategies (0.4%-2.8%).

CONCLUSIONS

Renal functional implications varied across management strategies for localized renal masses, with worse postoperative renal function for patients undergoing radical nephrectomy compared with other strategies and similar outcomes for partial nephrectomy and thermal ablation. Further attention is needed to quantify the changes in renal function associated with active surveillance and nephron-sparing approaches for patients with preexisting CKD.

Oncological and renal medical importance of kidney-sparing surgery

In the past decade, the medical and oncological rationale for kidney-sparing surgical approaches for small renal masses has been clarified. Although radical nephrectomy is still necessary for many patients diagnosed with large renal tumours, accumulating evidence indicates that partial nephrectomy provides equivalent oncological outcomes while also preserving renal function and preventing the adverse cardiovascular effects of chronic kidney disease. Furthermore, approximately 45% of resected small renal tumours are benign or indolent, with limited--if any--metastatic potential. Patients who develop kidney cancer often have medical comorbidities that can affect kidney function, such as diabetes and hypertension, and histological examination of the non-tumour-bearing elements of the kidney demonstrate significant pathological changes in the vast majority of patients. For elderly patients or patients with comorbidities, active surveillance provides an alternative kidney-sparing approach, and is associated with extremely low rates of clinical disease progression and metastases. Despite these important advances in understanding, which support the use of partial nephrectomy for the treatment of small renal masses, the technique remains underused.

Robot-assisted partial nephrectomy in contemporary practice

Laparoscopic renal surgery is associated with reduced blood loss, shorter hospital stay, enhanced cosmesis, and more rapid convalescence relative to open renal surgery. Laparoscopic partial nephrectomy (LPN) is a minimally invasive, nephron-sparing alternative to laparoscopic radical nephrectomy (RN) for the management of small renal masses. While offering similar oncological outcomes to laparoscopic RN, the technical challenges and prolonged learning curve associated with LPN limit its wider dissemination. Robot-assisted partial nephrectomy (RAPN), although still an evolving procedure with no long-term data, has emerged as a viable alternative to LPN, with favorable preliminary outcomes. This article provides an overview of the role of RAPN in the management of renal cell carcinoma. The clinical indications and principles of surgical technique for this procedure are discussed. The oncological, renal functional, and perioperative outcomes of RAPN are also evaluated, as are complication rates.

The first assistant sparing technique robot-assisted partial nephrectomy decreases warm ischemia time while maintaining good perioperative outcomes

BACKGROUND AND PURPOSE

Prolonged warm ischemia time (WIT) and operative time (OT) during robot-assisted partial nephrectomy (RAPN) can adversely affect renal function and clinical outcomes. Minimizing the duration of WIT and OT is critical to achieving good results postoperatively. Our standard technique for RAPN has evolved into an intracorporeal preparation (ICP) that minimizes the reliance on the first assistant. The goal of the current study was to analyze outcomes after ICP RAPN compared with those of the standard RAPN.

PATIENTS AND METHODS

A retrospective review of all patients who underwent RAPN was performed, comparing standard vs ICP technique. The ICP approach involves tacking of preprepared sutures along the abdominal sidewall adjacent to the kidney in preparation for hemostasis and renorrhaphy before arterial clamping, the use of robotic Scanlan(®) Reliance, bulldog clamps preplaced near the hilum of the kidney, and "sliding-clip" renorrhaphy. We compared intraoperative (OT, WIT, estimated blood loss [EBL]) and pre/postoperative outcomes (serum creatinine, glomerular filtration rate [GFR], length of stay [LOS]) of RAPN between the ICP and standard approach.

RESULTS

A total of 44 consecutive RAPNs (18 ICP, 26 standard) were performed. Median nephrometry score was 7a, and mean follow-up was 13 months. Mean tumor size was 2.4 cm, and most common stage was T(1a). There was no significant difference between ICP and standard RAPN with regard to nephrometry score and stage. Mean WIT was significantly lower for the ICP vs standard RAPN (19 vs 23 min, P=0.049) as was mean OT (161 vs 204 min, P=0.027). On multivariate analysis, ICP RAPN was an independent predictor of WIT (P=0.02). There was no significant impact on preoperative and postoperative GFR for either approach. EBL and LOS were similar between the two groups.

CONCLUSIONS

The ICP RAPN leads to a significant reduction in WIT and OT while maintaining similar perioperative outcomes compared with the standard approach.

Renal functional and perioperative outcomes of off-clamp versus clamped robot-assisted partial nephrectomy: matched cohort study

OBJECTIVE

To evaluate the potential benefit of performing off-clamp robot-assisted partial nephrectomy as it relates to renal functional outcomes, while assessing the safety profile of this unconventional surgical approach.

METHODS

Twenty-nine patients who underwent off-clamp robot-assisted partial nephrectomy for suspected renal cell carcinoma at Washington University between March 2008 and September 2011 (group 1) were matched to 29 patients with identical nephrometry scores and comparable baseline renal function who underwent robot-assisted partial nephrectomy with hilar clamping during the same period (group 2). The matched cohorts' perioperative and renal functional outcomes were compared at a mean 9-month follow-up.

RESULTS

Mean estimated blood loss was 146.4 mL in group 1, versus 103.9 mL in group 2 (P = .039). Mean hilar clamp time was 0 minutes in group 1 and 14.7 minutes in group 2. No perioperative complications were encountered in group 1; 1 Clavien-2 complication (3.4%) occurred in group 2 (P = 1.000). At 9-month follow-up, mean estimated glomerular filtration rate in group 1 was 79.9 versus 84.8 mL/min/1.73 m(2) preoperatively (P = .013); mean estimated glomerular filtration rate in group 2 was 74.1 versus 85.8 mL/min/1.73 m(2) preoperatively (P < .001). Hence, estimated glomerular filtration rate declined by a mean of 4.9 mL/min/1.73 m(2) in group 1 versus 11.7 mL/min/1.73 m(2) in group 2 (P = .033).

CONCLUSION

Off-clamp robot-assisted partial nephrectomy is associated with a favorable morbidity profile and relatively greater renal functional preservation compared to clamped robot-assisted partial nephrectomy. Nevertheless, the benefit is small in renal functional terms and may have very limited clinical relevance.

Comparative study between trimetazidine and ice slush hypothermia in protection against renal ischemia/reperfusion injury in a porcine model

PURPOSE

The aim of the study was to compare the effects of renal ice slush hypothermia and the use of trimetazidine in the protection against ischemia/reperfusion (I/R) injury.

MATERIALS AND METHODS

Fifteen farm pigs were submitted to left kidney ischemia and right nephrectomy during the same procedure. Animals were divided into three groups. Group 1 was submitted to warm ischemia; Group 2 was submitted to cold ischemia with ice slush; and Group 3 received trimetazidine 20 mg one day and 4 hours before surgery. Ischemia time was 120 minutes in all three groups. Serum creatinine (SCr) and plasma iohexol clearance (CLioh) were measured before surgery and on postoperative days (PODs) 1,3,7, and 14. Semi-quantitative analyses of histological alterations were performed by a pathologist. A p value of < 0.05 was considered significant.

RESULTS

All groups showed elevation of serum creatinine in the first week. Serum creatinine was higher in Group 3 in the first and third postoperative days (Mean Cr: 5.5 and 8.1 respectively). Group 2 showed a lower increase in creatinine and a lower decrease in iohexol clearance than the others. Renal function stabilized in the fourteenth POD in all three groups. Analyses of histological alterations did not reach statistical significance between groups.

CONCLUSION

Trimetazidine did not show protection against renal I/R injury in comparison to warm ischemia or hypothermia in a porcine model submitted to 120 minutes of renal ischemia.

End stage and chronic kidney disease: associations with renal cancer

There is a well known association between end stage renal disease and the development of kidney cancer in the native kidney of patients requiring renal replacement therapy. There is now emerging evidence that lesser degrees of renal insufficiency (chronic kidney disease, CKD) are also associated with an increased likelihood of cancer in general and kidney cancer in particular. Nephropathological changes are commonly observed in the non-tumor bearing portions of kidney resected at the time of partial and radical nephrectomy (RN). In addition, patients with renal cancer are more likely to have CKD at the time of diagnosis and treatment than the general population. The exact mechanism by which renal insufficiency transforms normal kidney cells into tumor cells is not known. Possible mechanisms include uremic immune inhibition or increased exposure to circulating toxins not adequately cleared by the kidneys. Surgeons managing kidney tumors must have an increased awareness of their patient's renal functional status as they plan their resection. Kidney sparing approaches, including partial nephrectomy (PN) or active surveillance in older and morbidly ill patients, can prevent CKD or delay the further decline in renal function which is well documented with RN. Despite emerging evidence that PN provides equivalent local tumor control to RN while at the same time preventing CKD, this operation remains under utilized in the United States and abroad. Increased awareness of the bi directional relationship between kidney function and kidney cancer is essential in the contemporary management of kidney cancer.

Multivariate analysis of the factors involved in loss of renal differential function after laparoscopic partial nephrectomy: a role for warm ischemia time

BACKGROUND

Partial nephrectomy (PN) is now the gold standard for the surgical treatment of small renal masses. We evaluated the effect of WIT and other factors on RDF assessed by preoperative and postoperative renal scintigraphy.

METHODS

Between 2003 and 2008, 182 consecutive laparoscopic PN (LPN) were performed in an academic centre. Among those, 56 had mercaptoacetyl triglycine (MAG3) lasix renal scintigraphy preoperatively and postoperatively.

RESULTS

Medians for age, preoperative estimated glomerular filtration rate and computed tomography scan tumour size were 62 years, 82 mL/min/1.73m(2) and 26 mm, respectively. Median WIT and preoperative RDF were 30 minutes and 50%, respectively. Median loss of RDF after surgery was 14%. Linear regression curves showed that loss in RDF rate was 0.2% per minute when WIT was <30 minutes and 0.7% per minute when WIT was ≥30 minutes. In multivariate analysis, length of WIT and endophytic tumour location were associated with a statistically significant loss of RDF (p < 0.05), but only in the group who experienced >30 minutes of WIT.

INTERPRETATION

Our results suggest that the factors associated with loss of RDF are not the same before and after 30 minutes of WIT and that the rate of loss in RDF increases after 30 minutes. Since, the effect of WIT is small up to 30 minutes, we believe that surgery should focus on limiting the resection of normal parenchyma and to ensure negative margins and hemostasis, rather than on premature unclamping.

The role of surgery in the management of early-stage renal cancer

There were an estimated 58,240 new cases and 13,040 deaths from kidney cancer in the United States in 2010. The increased treatment and cure of small, incidentally discovered renal tumors, most of which are nonlethal in nature, has not offset the increased mortality caused by advanced and metastatic tumors. In this article, the optimum approach to the surgical management of localized renal tumors and its impact on renal function are discussed.

Robotic-assisted laparoscopic cryo-partial nephrectomy: a novel technique using cryoablation in lieu of hilar clamping in a porcine model

Laparoscopic and robotic-assisted partial nephrectomy has become an increasingly viable approach for the resection of renal tumors. There are several technical limitations in performing laparoscopic partial nephrectomy, the most significant being the inability to easily obtain cold ischemia which allows for an extended operative time. In this study, we evaluated the feasibility and efficacy of cryoablation as an alternative to hilar clamping to maintain hemostasis during robotic-assisted laparoscopic partial nephrectomy in a porcine model. Twelve female swine underwent nine open and eight robotic-assisted laparoscopic partial nephrectomies using modified cryoablative methods to create hemostasis. Renal perfusion imaged with indocyanine green (ICG) and histological analysis was assessed immediately after the procedure and at 3 weeks post-operatively. With two freeze/thaw cycles, all nine open and eight robotic-assisted laparoscopic partial nephrectomies were successfully completed without the need for hilar clamping. The mean blood loss for the open and robotic-assisted groups was 230.6 and 99.4 ml, respectively. In all cases, maintenance of renal perfusion was confirmed by the presence of a renal pulse and intraoperative ICG imaging immediately and 3 weeks post-operatively. The histological anatomy was well preserved in the resected segment following cryo-resection. After 21 days following cryo-resection, histological analysis demonstrated normal viable tissue with minimal scarring in the remaining kidney. The use of cryoablation created a zone of hemostasis without compromising the vascularity of the remaining kidney, while preserving the renal cytoarchitecture of the segment remove for pathological analysis. Further studies will help to delineate its usefulness in laparoscopic partial nephrectomy.

Assessing the impact of ischaemia time during partial nephrectomy

CONTEXT

The impact of applying renal ischaemia during nephron-sparing surgery to avoid renal damage in the treated kidney has gained importance in different surgical techniques.

OBJECTIVE

The main objective of the present study is to point out the limit of renal ischaemia times for warm and cold ischaemia approaches. Important results of research on renal ischaemia and different surgical techniques as well as results of clinical studies concerning renal function after renal ischaemia in partial nephrectomy are highlighted.

EVIDENCE ACQUISITION

A Medline literature research was performed, combining queries on the keywords nephron-sparing surgery, partial nephrectomy, and ischemia. Links to related articles and cross-reading of citations in related articles were surveyed, as were reviews, letters to editors, and information collected from urologic textbooks. The references formed the basis of this review article, with selection and deletion based on the relevance and importance of the content. In a final step, interactive peer review by the expert panel of coauthors completed the review.

EVIDENCE SYNTHESIS

Renal ischaemia research showed an increasing renal damage proportional to ischemic time. Current clinical data support safe ischaemia times, within 20 min of warm ischaemia and up to 2 h of cold ischaemia, to minimise renal ischemic damage. To date, no ischaemia dose-response curve or algorithm is available to predict the risk of acute kidney injury and chronic kidney disease in patients undergoing intraoperative ischaemia. In general, there seems to be a higher risk for comorbidity caused by renal damage in patients suffering from kidney tumour.

CONCLUSIONS

If ischaemia is required, the tumour should be removed within 20 min of warm ischaemia, regardless of surgical approach. Efforts should be made to start immediately with cold ischaemia, if the feasibility within this span of time seems to be jeopardised. Thus, cold ischaemia times up to 2 h can be tolerated by the kidney, depending on the individual method. Nevertheless, cold ischaemia with ice slush should be kept as short as possible--at best within 35 min. In ischemic nephron-sparing surgery, one of the surgeon's main aims should be to avoid loss of renal function. Only after optimal preoperative appraisal and planning can the best postoperative outcomes for renal function be achieved.

Decision tree for laparoscopic partial nephrectomy versus laparoscopic renal cryoablation for small renal masses

PURPOSE

We propose an algorithm to help guide surgeons' decisions between laparoscopic partial nephrectomy (LPN) and renal laparoscopic cryoablation (LCA) based on preoperative parameters and outcomes defined in the literature.

PATIENTS AND METHODS

From July 2004 to December of 2007, we performed 51 LPNs and 22 LCAs. We formulated an algorithm between LPN and LCA based on outcomes from published series. Candidates for LPN are younger than 70 years; have few comorbidities; masses < or = 7 cm; and solitary, solid, and or cystic masses with an exophytic or mesophytic location. Candidates for LCA are 70 years old or older, with multiple comorbidities, masses < or = 3.5 cm, multiple masses, solid masses only, and include endophytic or hilar tumors. We then applied this decision tree to our series.

RESULTS

Our results for LPN are statistically similar to the published series except there was a higher positive margin rate in our series (11.8 v 3.5%). Our LCA series had older patients (71 v 65 y), larger masses (3.2 v 2.5 cm), and a higher rate of bleeding necessitating transfusion (18%). We applied the algorithm to all 73 patients in our series. It estimated that 45 patients should undergo LPN and 28 should undergo LCA. A correlation between the predicted surgery and the surgery performed was seen, but approximately one in five patients would have a change in the surgery performed.

CONCLUSIONS

This algorithm validates decisions surgeons are already making between LPN and LCA. While not a perfect model, it can be used to help simplify decisions between these two minimally invasive procedures to achieve optimal outcomes.