Devascularized Parenchymal Mass Associated with Partial Nephrectomy: Predictive Factors and Impact on Functional Recovery

Every decade counts: a narrative review of functional recovery after partial nephrectomy

OBJECTIVE

To provide a narrative review of the major advances regarding ischaemia and functional recovery after partial nephrectomy (PN), along with the ongoing controversies.

METHODS

Key articles reflecting major advances regarding ischaemia and functional recovery after PN were identified. Special emphasis was placed on contributions that changed perspectives about surgical management. Priority was also placed on randomized trials of off-clamp vs on-clamp cohorts.

RESULTS

A decade ago, 'Every minute counts' was published, showing strong correlations between duration of ischaemia and development of acute kidney injury (AKI) and chronic kidney disease after clamped PN. This reinforced perspectives that ischaemia was the main modifiable factor that could be addressed to improve functional outcomes and helped spur efforts towards reduced or zero ischaemia PN. These approaches were associated with strong functional recovery and some peri-operative risk, although they were generally safe in experienced hands. Further research demonstrated that, when parenchymal volume changes were incorporated into the analyses, ischaemia lost statistical significance, and percent parenchymal volume saved proved to be the main determinant. Cold ischaemia was confirmed to be highly protective, and limited warm ischaemia also proved to be safe. The reconstructive phase of PN, with avoidance of parenchymal devascularization, appears to be most important for functional outcomes. Randomized trials of on-clamp vs off-clamp PN have shown minimal impact of ischaemia on functional recovery.

CONCLUSIONS

The past decade has witnessed great progress regarding functional recovery after PN, with many lessons learned. However, there are still unanswered questions, including: What is the threshold of warm ischaemia at which irreversible ischaemic injury begins to develop? Are some cohorts at increased risk for AKI or irreversible ischaemic injury? and Which patients should be prioritized for zero-ischaemia PN?

Robotic-assisted tumor enucleation versus standard margin partial nephrectomy: Perioperative, renal functional, and oncologic outcomes for low and intermediate complexity renal masses

PURPOSE

Standard margin partial nephrectomy (SPN) with sharp incision across normal renal parenchyma carries perioperative morbidity and renal functional implications. Tumor enucleation (TE) is an alternative approach using a natural plane of dissection around the tumor pseudocapsule to maximize parenchymal preservation. We compared perioperative, functional, and oncologic outcomes for robotic-assisted TE to SPN.

MATERIALS AND METHODS

Patients ≥18 years of age undergoing robotic-assisted TE or SPN were included (2008-2020). Baseline demographics and tumor characteristics were compared. Perioperative, renal functional, and oncologic outcomes were assessed for comparative effectiveness.

RESULTS

A total of 467 patients were included with 176 (37.7%) TE and 291 (62.3%) SPN. Baseline characteristics and final histology were comparable; 18% of patients had baseline stage 3 chronic kidney disease. TE had lower median blood loss, operative time, length of stay, and fewer complications compared to SPN. Positive margin rates were higher for TE vs. SPN (8.5% vs. 3.4%, P = 0.04) with similar recurrence rates (2.3% vs. 3.4%, P = 0.48) and no difference in cancer-specific or overall survival with median 4.0 years follow-up. Baseline estimated glomerular filtration rate was comparable (76.1 vs. 78.2, P = 0.63) while renal function in the first year was better preserved with TE (74.6 vs. 68.1, P < 0.001) showing an 8-point estimated glomerular filtration rate (P = 0.001) advantage after adjustment. The rate of stage ≥3 chronic kidney disease by 12 months was lower for TE compared to SPN (21.5% vs. 34.1%, P = 0.006).

CONCLUSIONS

TE is an alternative approach to SPN associated with favorable perioperative and renal functional outcomes. While positive margin rates are higher, longer-term recurrence rates are no different suggesting pseudocapsule disruption during TE has limited impact on oncologic outcomes.

Robot-assisted versus conventional laparoscopic partial nephrectomy for renal hilar tumors: Parenchymal preservation and functional recovery

OBJECTIVE

To determine whether robot-assisted laparoscopic partial nephrectomy (RALPN) can benefit patients in terms of functional recovery in the treatment of renal hilar tumors compared to conventional laparoscopic partial nephrectomy (CLPN).

METHODS

Between January 2019 and July 2021, patients with hilar tumors who underwent partial nephrectomy (PN) were acquired at our center and were classified into RALPN and CLPN groups. Ipsilateral parenchymal volume (IPV) and glomerular filtration rate (GFR) were determined independently 3-5 days before and 3 months after PN using contrast-enhanced computed tomography and nuclear renal scans. Pearson correlation was used to determine the link between ipsilateral GFR preservation and IPV preserved. Concurrently, multivariable analysis was employed to determine characteristics associated with functional recovery.

RESULTS

A total of 96 patients with hilar tumors were studied, of which 41 received RALPN and 55 received CLPN. Excisional parenchymal volume was 27 and 37 cm³ (p = 0.005) in RALPN and CLPN groups, respectively, and IPV preserved was 77% and 68% (p < 0.001). Furthermore, the ipsilateral GFR preserved was 77.7% and 75.3%, respectively (p = 0.003). On Pearson correlation, ipsilateral GFR preservation was linked with IPV preserved (r = 0.36, p < 0.001). According to a multivariate study, baseline GFR, IPV preserved, and surgical procedures (RALPN vs. CLPN) were significant factors influencing functional recovery.

CONCLUSION

Our study suggests that RALPN, rather than CLPN, can achieve better functional recovery in the treatment of hilar tumors due to its ability to win more IPV preserved. RALPN should be recommended as the first-line treatment for hilar tumors, but randomized controlled trials are required to validate our findings.

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.

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.

Comparison of Sutureless Versus Suture Partial Nephrectomy for Clinical T1 Renal Cell Carcinoma: A Meta-Analysis of Retrospective Studies

Background

Partial nephrectomy (PN) is the recommended treatment for T1 renal cell carcinoma (RCC). Compared with suture PN, sutureless PN reduces the difficulty and time of operation, but the safety and feasibility have been controversial. This meta-analysis was conducted to compare the function and perioperative outcomes of suture and sutureless PN for T1 RCC.

Methods

Systematic literature review was performed up to April 2021 using multiple databases to identify eligible comparative studies. According to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria, identification and selection of the studies were conducted. Meta-analysis was performed for studies comparing suture to sutureless PN for both T1a and T1b RCC. In addition, subgroup analysis was performed on operation time, warm ischemia time, estimated blood loss, and postoperative complications. Sensitivity analysis was used in analysis with high heterogeneity (operation time and estimated blood loss).

Results

Eight retrospective studies were included with a total of 1,156 patients; of the 1,156 patients, 499 received sutureless PN and 707 received suture PN. The results showed that sutureless PN had shorter operative time (I² = 0%, P < 0.001), warm ischemia time (I² = 97.5%, P < 0.001), and lower clamping rate (I² = 85.8%, P = 0.003), but estimated blood loss (I² = 76.6%, P = 0.064) had no difference. In the comparison of perioperative outcomes, there was no significant difference in postoperative complications (I² = 0%, P = 0.999), positive surgical margins (I² = 0%, P = 0.356), postoperative estimated glomerular filtration rat (eGFR) (I² = 0%, P = 0.656), and tumor recurrence (I² = 0%, P = 0.531).

Conclusions

In T1a RCC with low RENAL score, sutureless PN is a feasible choice, whereas it should not be overestimated in T1b RCC.

Long-Term Oncologic Outcomes After Laparoscopic and Robotic Tumor Enucleation for Renal Cell Carcinoma

OBJECTIVES

Tumor enucleation (TE) optimizes parenchymal preservation with promising short-term oncologic outcomes compared with standard partial nephrectomy (SPN). However, researches/literatures about long-term oncologic outcomes for TE after minimally invasive surgery are scarce. We aim to analyze long-term oncologic outcomes after laparoscopic and robotic tumor enucleation for renal cell carcinoma (RCC).

PATIENTS AND METHODS

We retrospectively analyzed 146 patients who underwent TE with either laparoscopic or robotic approach for localized RCC in our center. Local recurrence, cancer specific survival (CSS), recurrence free survival (RFS), and overall survival (OS) were the main outcomes. Survival curves were generated using a Kaplan-Meier method. Perioperative outcomes and pathological outcomes were also analyzed.

RESULTS

Overall, 98 male and 48 female patients were eligible for the study. The median tumor size was 3.4 cm with a median R.E.N.A.L. score of seven. Warm ischemia was used in 143 patients with a median ischemia time of 20 min and three patients had zero ischemia. Five patients (3.4%) had major complications (> Clavien IIIa) and only two were related to urinary system. The median global glomerular filtration rate (GFR) preserved after surgery was 93%. Pseudocapsule invasion was reported in 50 tumors (34%) and positive surgical margins were found in 3/146 (2.1%) tumors. At a median follow-up of 66 months, local recurrence happened in two patients (1.4%), and systemic recurrence happened in six patients (4.2%). The 5-year CSS, RFS, OS were 95.7, 89.6, and 91.9%, and the 10-year CSS, RFS, OS were 93.8, 89.6, and 90.0%, respectively.

CONCLUSION

This study indicates that tumor enucleation with laparoscopic or robotic approach in experienced hands for the treatment of RCC appears oncologically safe with a median follow-up of more than 5 years. Prospective studies with more patients and longer follow-up will be required to further evaluate oncologic safety after TE.

Renal Volume Loss During Partial Nephrectomy Due to Resected Healthy Parenchyma: A Tool for Quick Estimation

Purpose: Our objective is to evaluate a technique for estimating the amount of healthy margin resected during partial nephrectomy (PN). Materials and Methods: The resected healthy margin volume was determined by planimetry (gold standard), which was performed in a prospective manner on 30 freshly resected renal masses by cross-sectional slicing every ∼5 mm. A single cross-sectional slice containing the largest tumor diameter (bivalved tumor) was chosen to build a model for estimating the amount of healthy kidney removed. This single-slice technique was then applied to a second series of patients (n = 39) status post PN. Three-dimensional models were created using pre- and postoperative CT scans to determine the overall volume loss following PN. Results: The median (range) for tumor diameter and tumor volume was 3.2 cm (1-6.1) and 10.7 cm³ (0.5-101.9), respectively, for the 30 PN specimens used to build the single-slice estimation equation. The median (range) healthy margin volume calculated by planimetry and single slice technique was 9.0 cm³ (1.0-22.1) and 7.8 cm³ (1.0-31.0), respectively (p = 0.37). The Pearson correlation was 0.84, and the median (range) percent difference between the planimetry and single slice techniques was -0.5% (-39% to 57%). For the 39 PN patients, the median (range) total renal volume loss, 25.8 cm³ (3-79), was significantly greater than the volume of healthy margin removed during resection, 5.7 cm³ (1-22), p < 0.001. Conclusions: The healthy margin resected during PN differs widely and can be estimated from a single cross-section. The healthy margin resected accounted for <50% of the total volume loss seen during PN.

The Use of Tissue Adhesive for Tumor Bed Closure during Partial Nephrectomy is Associated with Reduced Devascularized Functional Volume Loss

Objectives

To quantitatively compare the functional renal volume loss, following nephron sparing surgery (NSS) between patients in whom tumor bed closure was done by biological tissue adhesive and those who were managed by standard suture technique.

Methods

From our institutional NSS database we retrospectively collected patients who had two sequential quantitative single-photon emission computed tomography of ^99mTc-dimercaptosuccinic acid uptake studies, the first study immediately before surgery and the second one 3-6 months following surgery. The study group included 69 patients: 26 (37.7%) patients in the sealant group (BioGlue®) and 43 (62.3%) patients in the standard suture group.

Results

No statistically significant differences were noted in the baseline clinical and pathological characteristics of the studied groups. However, there were several statistically significant differences in operative variables: patients in the suture group had larger amount of blood loss (3-fold), longer ischemia time (26.6 vs. 21 minutes,) and slightly longer operation time. Patients in whom tumor bed was closed by sutures had nearly 3-fold higher parenchymal loss compared to patients managed by sealant (26.28 vs. 8.92 ml, p = 0.048).

Conclusions

The use of tissue sealant during tumor bed reconstruction is associated with reduced devascularized parenchymal mass loss and should be considered among modifiable surgical factors during NSS.

The role of three-dimensional reconstruction in laparoscopic partial nephrectomy for complex renal tumors

BACKGROUND

To evaluate the role of three-dimensional (3D) reconstruction technique in renal function protection and ipsilateral parenchymal mass preserved after laparoscopic partial nephrectomy (LPN) in patients with complex renal tumor (R.E.N.A.L.score ≥ 8).

METHODS

A retrospective study enrolling 49 patients who suffered from RCC and underwent LPN at our center, from October 1, 2017, to October 31, 2018. Twenty-one patients (group A) underwent LPN with the 3D reconstruction technique before surgery, and the other 28 patients (group B) not. Preoperative and postoperative ipsilateral parenchymal mass volume and ipsilateral glomerular filtration rate (GFR) were analyzed 3-5 days prior and 3 months after PN. In order to compare the two groups, Mann-Whitney U test and chi-square tests were performed. The main limitation of this technique is that the volume calculations are partly performed manually.

RESULTS

All patients' median renal score was 10 with no difference between the two groups (P = 0.89), and the median tumor size of the two groups was 3.2 cm (group A) and 3.3 cm (group B) respectively (P = 0.14). In addition, the median warm ischemia time of the two groups was 21 min (group A) and 26 min (group B) (P = 0.003). In group A and group B, the rate of preserved global GFR was 88% and 86% (P = 0.06), preserved ipsilateral GFR was 80% and 77% (P = 0.01), and preserved ipsilateral parenchymal was 84% and 80% (P = 0.03) separately.

CONCLUSION

3D reconstruction technique was a beneficial method for more renal function and more preserved renal parenchymal mass volume after LPN.

TRIAL REGISTRATION

Yantai Yuhuangding Hospital, YHD[2017]212. Registered 1 January 2017 (prospectively registered), http://www.ytyhdyy.com/nav/103.htm .

Outcome of kidney function after ischaemic and zero-ischaemic laparoscopic and open nephron-sparing surgery for renal cell cancer

Background

Nephron-sparing surgery (NSS) remains gold standard for the treatment of localised renal cell cancer (RCC), even in case of a normal contralateral kidney. Compared to radical nephrectomy, kidney failure and cardiovascular events are less frequent with NSS. However, the effects of different surgical approaches and of zero ischaemia on the postoperative reduction in renal function remain controversial.

We aimed to investigate the relative short- and long-term changes in estimated glomerular filtration rate (eGFR) after ischaemic or zero-ischaemic open (ONSS) and laparoscopic NSS (LNSS) for RCC, and to analyse prognostic factors for postoperative acute kidney injury (AKI) and chronic kidney disease (CKD) stage ≥3.

Methods

Data of 444 patients (211 LNSS, 233 ONSS), including 57 zero-ischaemic cases, were retrospectively analysed. Multiple regression models were used to predict relative changes in renal function. Natural cubic splines were used to demonstrate the association between ischaemia time (IT) and relative changes in renal function.

Results

IT was identified as significant risk factor for short-term relative changes in eGFR (ß = − 0.27) and development of AKI (OR, 1.02), but no effect was found on long-term relative changes in eGFR. Natural cubic splines revealed that IT had a greater effect on patients with baseline eGFR categories ≥G3 concerning short-term decrease in renal function and development of AKI. Unlike LNSS, ONSS was significantly associated with short-term decrease in renal function (ß = − 13.48) and development of AKI (OR, 3.87). Tumour diameter was associated with long-term decrease in renal function (ß = − 1.76), whereas baseline eGFR was a prognostic factor for both short- (ß = − 0.20) and long-term (ß = − 0.29) relative changes in eGFR and the development of CKD stage ≥3 (OR, 0.89).

Conclusions

IT is a significant risk factor for AKI. The short-term effect of IT is not always linear, and the impact also depends on baseline eGFR. Unlike LNSS, ONSS is associated with the development of AKI. Our findings are helpful for surgical planning, and suggest either the application of a clampless NSS technique or at least the shortest possible IT to reduce the risk of short-time impairment of the renal function, which might prevent AKI, particularly regarding patients with baseline eGFR category ≥G3.

Ischemia Techniques in Nephron-sparing Surgery: A Systematic Review and Meta-Analysis of Surgical, Oncological, and Functional Outcomes

CONTEXT

The optimal ischemia technique at partial nephrectomy (PN) for renal masses is yet to be determined.

OBJECTIVE

To summarize and analyze the current evidence about surgical, oncological, and functional outcomes after different ischemia techniques (cold, warm, and zero ischemia) at PN.

EVIDENCE ACQUISITION

A computerized systematic literature search was performed by using PubMed (MEDLINE) and Science Direct. Identification and selection of the studies were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria. Outcomes of interest were estimated blood loss (EBL), overall complications, positive surgical margins, local tumor recurrence, and renal function preservation. Meta-analysis and forest-plot diagrams were performed. Overall pooled estimates, together with 95% confidence intervals (CIs), of the incidence of all parameters were obtained using a random effect model (RE-Model) on the log transformed means (MLN), proportion, or standardized mean change, as deemed appropriate.

EVIDENCE SYNTHESIS

One hundred and fifty-six studies were included. No clinically meaningful differences were found in terms of EBL after cold (mean: 215.5; 95% CI: 154.2-276.8m), warm (mean: 201.8; 95% CI: 175.0-228.7ml), or zero (mean: 261.2; 95% CI: 171.0-351.3ml) ischemia technique. Overall, postoperative complications were recorded in 14.1% (95% CI: 6.7-27.4), 11.1% (95% CI: 10.0-12.3), and 9.7% (95% CI: 7.7-12.2) of patients after cold, warm, and zero ischemia (p<0.01), respectively. Positive surgical margins were recorded in 4.8% (95% CI: 1.9-10.9), 4.0% (95% CI: 3.4-4.8), and 5.6% (95% CI: 3.1-9.8) of patients after cold, warm, and zero ischemia (p<0.01), respectively. Local recurrence was recorded in 3.2% (95% CI: 1.9-5.2) and 3.1% (95% CI: 0.7-11.5) of patients after warm and zero ischemia (p<0.01), respectively. The log₂ of estimated glomerular filtration ratio mean changes were-1.37 (95% CI:-3.42 to 0.68),-1.00 (-2.04 to 0.03), and-0.71 (-1.15 to-0.27) ml/min after cold, warm, and zero ischemia, respectively. Low level of evidence, retrospective nature of most of included studies, a high risk of selection bias, and heterogeneity within included studies limited the overall quality of the analysis.

CONCLUSIONS

The effect of ischemia technique at PN is still debatable and subject to confounding by several factors, namely, patients' selection criteria, surgical technique used, and percentage of functional parenchyma spared during surgery. These confounders bias available evidence and were addressed by only a small part of available studies. Unfortunately, the overall quality of literature evidences and the high risk of selection bias limit the possibility of any causal interpretation about the relationship between the ischemia technique used and surgical, oncological, or functional outcomes. Thus, none of the available ischemia technique could be recommended over the other.

PATIENT SUMMARY

The present analysis shows that none of the available ischemia techniques, namely, cold, warm, or zero ischemia, is universally superior to the others, and other factors play a role in the surgical outcome.

Acute kidney injury and intermediate-term renal function after clampless partial nephrectomy

OBJECTIVES

To evaluate the incidence and predictors of acute kidney injury after clampless partial nephrectomy, and its impact on intermediate-term renal function.

METHODS

The incidence and severity of acute kidney injury were assessed for 262 patients undergoing clampless partial nephrectomy between 2010 and 2015. The association between perioperative covariates and acute kidney injury was evaluated using multivariate logistic regression analysis. An annual change in estimated glomerular filtration rate from 1 year after surgery was calculated according to the presence or absence of acute kidney injury. An impact of acute kidney injury on postoperative renal impairment, defined as a ≥25% estimated glomerular filtration rate decrease, was evaluated.

RESULTS

Overall, 21 (8.0%) patients experienced grade 1 acute kidney injury after clampless partial nephrectomy, and grade ≥2 acute kidney injury was not observed. High tumor complexity was the only independent predictor of acute kidney injury. Estimated glomerular filtration rate in patients with acute kidney injury improved within 1 year, and annual estimated glomerular filtration rate changes were similar among patients with or without acute kidney injury. Ultimately, 13 (5.0%) patients showed postoperative renal impairment during the median follow-up period of 37 months. Advanced age and diabetes mellitus were independent risk factors for renal impairment, but acute kidney injury was not.

CONCLUSIONS

The incidence and severity of acute kidney injury after clampless partial nephrectomy are low. Low-grade acute kidney injury after clampless partial nephrectomy does not seem to affect intermediate-term renal function.

Impact of preoperative calculation of nephron volume loss on future of partial nephrectomy techniques; planning a strategic roadmap for improving functional preservation and securing oncological safety

OBJECTIVES

To assess the correlation of the resected and ischaemic volume (RAIV), which is a preoperatively calculated volume of nephron loss, with the amount of postoperative renal function (PRF) decline after minimally invasive partial nephrectomy (PN) in a multi-institutional dataset.

PATIENTS AND METHODS

We identified 348 patients from March 2005 to December 2013 at six institutions. Data on all cases of laparoscopic (n = 85) and robot-assisted PN (n = 263) performed were retrospectively gathered. Univariable and multivariable linear regression analyses were used to identify the associations between various time points of PRF and the RAIV, as a continuous variable.

RESULTS

The mean (sd) RAIV was 24.2 (29.2) cm³ . The mean preoperative estimated glomerular filtration rate (eGFR) and the eGFRs at postoperative day 1, 6 and 36 months after PN were 91.0 and 76.8, 80.2 and 87.7 mL/min/1.73 m² , respectively. In multivariable linear regression analysis, the amount of decline in PRF at follow-up was significantly correlated with the RAIV (β 0.261, 0.165, 0.260 at postoperative day 1, 6 and 36 months after PN, respectively). This study has the limitation of its retrospective nature.

CONCLUSION

Preoperatively calculated RAIV significantly correlates with the amount of decline in PRF during long-term follow-up. The RAIV could lead our research to the level of prediction of the amount of PRF decline after PN and thus would be appropriate for assessing the technical advantages of emerging techniques.