Ipsilateral renal function preservation after robot‐assisted partial nephrectomy (RAPN): an objective analysis using mercapto‐acetyltriglycine (MAG3) renal scan data and volumetric assessment

Abstract

ObjectiveTo objectively assess ipsilateral renal function (IRF) preservation and factors influencing it after robot-assisted partial nephrectomy (RAPN). Patients and MethodsOur database was queried to identify patients who had undergone RAPN from 2007 to 2013 and had complete preand postoperative mercapto-acetyltriglycine (MAG3) renal scan assessment. The estimated glomerular filtration rate (eGFR) for the operated kidney was calculated by multiplying the percentage of contribution from the renal scan by the total eGFR. IRF preservation was defined as a ratio of the postoperative eGFR for the operated kidney to the preoperative eGFR for the operated kidney. The percentage of total eGFR preservation was calculated in the same manner (postoperative eGFR/preoperative eGFR × 100). The amount of healthy rim of renal parenchyma removed was assessed by deducting the volume of tumour from the volume of the PN specimen assessed on pathology. Multivariable linear regression was used for analysis. ResultsIn all, 99 patients were included in the analysis. The overall median (interquartile range) total eGFR preservation and IRF preservation for the operated kidney was 83.83 (75.2-94.1)% and 72 (60.3-81)%, respectively (P < 0.01). On multivariable analysis, volume of healthy rim of renal parenchyma removed, warm ischaemia time (WIT) > 30 min, body mass index (BMI) and operated kidney preoperative eGFR were predictive of IRF preservation. ConclusionsUsing total eGFR tends to overestimate the degree of renal function preservation after RAPN. This is particularly relevant when studying factors affecting functional outcomes after nephron-sparing surgery. IRF may be a more precise assessment method in this setting. Operated kidney baseline renal function, BMI, WIT >30 min, and amount of resected healthy renal parenchyma represent the factors with a significant impact on the IRF preservation. RAPN provides significant preservation of renal function as shown by objective assessment criteria.

Ipsilateral renal function preservation following minimally invasive partial nephrectomy: The effect of tumour characteristics and warm ischemic time

“…14,19,20 Furthermore, WIT was independent of preoperative variables (tumour size, RNS, and RNS variables), as well as perioperative variables (piece size and RP). Efforts to reduce WIT during PN, therefore, should be pursued.…”

“…This is consistent with previous studies that have found a significant association between higher RNS and loss of functional renal parenchyma, blood loss, WIT, and perioperative complications in minimally invasive PN. 11,18 A similar study investigating IRF by Zargar,14 however, found that RNS was not predictive of %IRF. This discrepancy in findings may be attributed to differences in WIT, as their study included zero ischemia techniques and had a median WIT of 20 minutes, compared with 29 minutes in our study.…”

“…The ellipsoid calculation has been used in previous studies to assess renal tumour size. 14,15 Piece size was calculated using a cone formula (V=πr²h/3) where r and h were the two largest measurements determined on pathological assessment. Volume of resected renal parenchyma (RP) was calculated by subtracting the tumour size from the corresponding piece size.…”

“At‐risk” kidney: How surgical factors influence renal functional preservation after partial nephrectomy

“…Specimens were routinely defatted at the time of PN. EVL was calculated using existing pathological measurements, and was defined as the difference between specimen and tumor volume, calculated using ellipsoid formulas, which amounts to the rim of healthy excised parenchyma . This variable was assessed with ladder plots and log‐transformed to achieve a linear relationship with the dependent variable.…”

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

“…Excisional volume loss (EVL) represents the excised normal renal parenchyma around the tumor, which was estimated as the difference between the specimen and tumor volume [13].…”