Analysis of the prognostic factors of renal function after nephron sparing surgery

Abstract

Objective To investigate the prognostic factors of renal function after nephron sparing surgery (NSS) in renal tumor patients. Methods The data of 115 patients who underwent NSS in our hospital from December 2016 to December 2018 were retrospectively analyzed. There were 75 males and 40 females, aged (49.50±12.94) years. The body mass index was (24.59±3.59) kg/m2. The maximum diameter of the tumor was (3.66±1.32) cm. The R. E.N.A.L. score was (6.43±1.60). Laparoscopic partial nephrectomy was performed in 61 cases and robot-assisted laparoscopic partial nephrectomy was performed in 54 cases, and all of which were successfully completed. Operative time, WIT and postoperative pathological results were recorded. Blood creatinine value, GFR of affected kidney, GFR of healthy kidney, total GFR, GFR preserving rate (the ratio of postoperative GFR to preoperative GFR), functioning parenchymal volume (FPV) of the affected kidneys, and FPV preserving rate of the affected kidneys (the ratio of postoperative FPV and preoperative FPV) were recorded 6 months after surgery. FPV was measured by the ellipsoid approximation on CT images before and after surgery. Paired sample t test was used to compare GFR and FPV before and after surgery. Spearman rank correlation analysis was used to evaluate the correlation between the study factors and GFR preserving rate of the affected kidneys. Multivariate linear regression models were used to analyze independent predictors of renal function of the affected kidneys. Independent sample t test was used for comparison between group of WIT≤25 min and group of WIT>25 min. Results All of the 115 patients in this study underwent successfully operations, with the median operation time of 135(75-245) min, and WIT(24.57±5.51) min. Postoperative GFR of the affected kidneys(35.50±7.81)ml/(min·1.73 m2) was significantly different from preoperative GFR(P 25 min group had a significantly lower GFR preserving rate of the affected kidneys than WIT≤25 min group [(68.77±10.88)% vs.(79.34±8.88)%, P<0.001]. Conclusions In the case of short WIT (<30 min), the reservation of normal renal tissue is the most important variable prognostic factor of renal function after NSS, and short WIT plays a secondary role. Under the premise of complete tumor resection, normal renal tissue should be reserved as much as possible and WIT should be controlled within 25 min. Key words: Kidney neoplasms; Nephron sparing surgery; Renal function; Warm ischemia