The superiority of contact surface area as a predictor of renal cortical volume change after partial nephrectomy compared to RENAL, PADUA and C-index: an approach using computed tomography-based renal volumetry

Nephrometric scoring system: Recent advances and outlooks

A nephrometry scoring system is a key standard to evaluate the feasibility of partial nephrectomy (PN). Whether based on two-dimensional or three-dimensional images, simplicity, effectiveness, and practicality are the keys to the nephrometric scoring system. Since the emergence of RENAL score in 2009, numerous scoring systems based on different anatomical parameters are established to seek accurately and few parameters to assess the risk of PN and complications. This study aimed to achieve a three-game winning streak in PN more easily and efficiently (negative resection margin, maximum preservation of normal nephron function, and avoiding short-term and long-term complications). Using PubMed, we counted 28 kinds of nephrometric scoring systems. We considered only English literatures published and excluded editorials, commentaries, and meeting abstracts. To the best of our knowledge, this is to date and most comprehensive summary as well as an outlook of the nephrometric scoring system.

Parallel comparison of R.E.N.A.L., PADUA, and C-index scoring systems in predicting outcomes after partial nephrectomy: A systematic review and meta-analysis

Objective

To parallelly compare the applicability of the radius, exophytic/endophytic, nearness, anterior/posterior, location nephrometry score (R.E.N.A.L.), the Preoperative Aspects and Dimensions Used for an Anatomical (PADUA), and the centrality index (C‐index) scoring systems in predicting clinical outcomes after partial nephrectomy (PN).

Methods

We searched EMBASE, PubMed, Ovid, and Web of Science to perform a meta‐analysis examining the correlation coefficients between three nephrometry scores (NSs) and warm ischemia time (WIT), estimated blood loss (EBL), operation time (OT), length of stay (LOS), and absolute change in eGFR (ACE) up to 25 January 2021.

Results

In total, 13 studies including 1496 patients met the criteria for further analysis. Overall, all scoring systems had statistically significant correlations with the WIT, EBL, OT, ACE and LOS and ACE, except for the correlation between PADUA and LOS (r = 0.16 [−0.00, 0.31], p > 0.05). The C‐index had the strongest correlation with WIT (r = −0.35 [−0.43, −0.26], p < 0.05) and ACE (r = −0.29 [−0.48, −0.10], p < 0.05). Weak correlations were observed between OT as well as EBL and each scoring system. Publication bias was observed in PADUA score predicting ACE (p = 0.04) and high heterogeneity was found in some of our results.

Conclusion

Until now, this is the first meta‐analysis that parallelly compares these three scoring systems in predicting outcomes after PN. We found that all NSs showed a statistically significant correlation with WIT, EBL, OT, and ACE. Moreover, the C‐index scoring system is the best predictor of WIT and ACE. Due to the existence of publication bias and high heterogeneity, more well‐designed and large‐scale studies are warranted for validation.

To our knowledge, this is the first meta‐analysis that parallelly compares these three scoring systems in predicting outcomes after PN. Overall, three scoring systems were significantly correlated with WIT, EBL, OT and ACE. Moreover, the C‐index scoring system outperformed R.E.N.A.L. and PADUA scoring systems in WIT and ACE.

The associations of RENAL, PADUA and C-index nephrometry scores with perioperative outcomes and postoperative renal function in minimally invasive partial nephrectomy

OBJECTIVE

This study aimed to assess the utility of the radius, exophytic/endophytic, nearness, anterior/posterior, location (RENAL); preoperative aspects and dimensions used for an anatomic evaluation (PADUA), and centrality index (C-index) scores for the outcomes of partial nephrectomy (PN).

MATERIAL AND METHODS

The patients who underwent PN with contrast-enhanced preoperative imaging from January 2015 to June 2018 were identified. The RENAL, PADUA, and C-index scores were assigned. The correlation between these scoring systems and perioperative and long-term renal functional outcomes were evaluated.

RESULTS

A total of 78 patients were included in the study (58 men and 20 women; age, 58±11.4 years). Median warm ischemia time (WIT), estimated blood loss (EBL), and operation time (OT) were 26 min, 115 mL, and 140 min, respectively. The RENAL score was related to WIT, EBL, and OT (p<0.001, p=0.003, and p=0.023, respectively). The PADUA score was associated with WIT, EBL, and OT (p<0.001, p=0.013, and p=0.005, respectively). The C-index score was correlated with WIT, EBL, and OT (p<0.001, p=0.010, and p=0.001, respectively). The C-index score also correlated with the percentage change in the estimated glomerular filtration rate (p=0.037). However, on univariable and multivariable regression analyses, only WIT significantly affected the postoperative estimated glomerular filtration rate reduction.

CONCLUSION

The RENAL, PADUA, and C-index scores were significantly associated with perioperative outcomes of PN. In addition, the C-index score was correlated with long-term renal functional outcomes.

The role of RENAL, PADUA, C-index, CSA nephrometry systems in predicting ipsilateral renal function after partial nephrectomy

Background

Functional outcome is an important issue in nephron-sparing surgery. Various nephrometries have been developed to predict renal function preservation. The aim of this study was to examine the applicability of R.E.N.A.L., PADUA, C-index, and mathematical tumor contact surface area (CSA) in predicting ipsilateral renal function after partial nephrectomy using radio-isotope scans.

Methods

We performed this retrospective study in patients who underwent partial nephrectomy between May 2013 and April 2017, and used abdominopelvic computerized tomography or magnetic resonance imaging to obtain R.E.N.A.L., C-index, and CSA. Renal function was measured by 99mTc mercaptoacetyltriglycine (MAG3). We evaluated correlations between nephrometries and perioperative parameters, and comparatively analyzed different nephrometries to determine the predictive ability in the percent change of effective renal plasma flow of the affected kidney.

Results

Three, two, and 35 patients received partial nephrectomy in open, laparoscopic, and robotic approaches, respectively. The median (IQR) tumor size was 3.13 (2.4) cm. The median (IQR) R.E.N.A.L., PADUA, C-index, and CSA scores were 7 (3), 8 (2), 2.01 (1.87), and 14.14 (19.25) cm², respectively. Spearman correlation analysis showed that four nephrometries were correlated with each other. The strongest correlations were between CSA and C-index (coefficient: − 0.885, p < 0.001), followed by R.E.N.A.L. and PADUA (coefficient: 0.778, p < 0.001). Ischemia time was significantly correlated with R.EN.A.L. (coefficient: 0.35, p = 0.025), PADUA (coefficient: 0.42, p = 0.007), C-index (coefficient: − 0.45, p = 0.004), and CSA (coefficient: 0.41, p = 0.009). In multivariate analysis, PADUA significantly affected ischemia time (p = 0.04). The percent change in effective renal plasma flow (PCE) of the operated kidney was correlated with PADUA (coefficient: 0.48 p = 0.002), C-index (coefficient: − 0.74, p < 0.001), and CSA (coefficient: 0.75, p < 0.001). Only CSA and C-index independently affected PCE (both p < 0.05) in multivariate analysis. In ROC curve analysis, both C-index and CSA could predict 20% change in effective renal plasma flow (AUC: 0.91 vs 0.86, p = 0.2) of the affected kidney.

Conclusions

We suggest using PADUA to evaluate surgical complexity and ischemia time. Regarding the accuracy of the prediction of post-operative ipsilateral renal function, both CSA and C-index outperformed R.E.N.A.L. and PADUA nephrometries.