| Background and Objective With the development of urology,the indications for Nephron Sparing Surgery(NSS)for renal tumors have gradually expanded and become more and more widely used.The implementation of NSS often leads to a decline in some kidney functions,and for the influence to the final renal function after NSS,renal ischemic injury caused by blocking the renal artery during NSS has caused controversy in recent years.Previous researches believed that its optimal control range should be less than 25 minutes and any extra warm ischemic time(WIT)will cause irreversible damage to the kidney,but many recent studies have considered that in many cases kidney function completely restored after warm ischemia time exceeds 30 minutes.And more attention is shifted to improving the accuracy of the operation,and retaining normally functioning renal parenchyma.Therefore,it is still of great clinical significance to discuss the threshold of warm ischemic time in NSS.This study analyzes the effect of warm ischemic time on warm ischemia after NSS operation by studying warm ischemic time and other related factors.Materials and Methods This study continuously collected 233 cases of clinical data from May 2019 to November 2019 in the Department of Urology,Shandong Provincial Hospital Affiliated to Shandong University,excluding isolated kidneys,incomplete clinical data,and cases with combined operations other than NSS,and finally included 220 cases,the data collected includes the patient's ase;gender;body mass index(BMI);whether it is associated with coronary heart disease,hypertension,diabetes;whether there were symptoms related to kidney cancer(triple sign of kidney cancer:hematuria.abdominal pain,abdominal mass);the largest diameter,location(left and right sides)and malignancy of renal tumors;surgical approach and methods of NSS surgery;warm ischemic time;estimated bleeding volume and length of surgery;total hospital stay;preoperative as well as the short-term postoperative blood creatinine and cystatin C values;the short-term postoperative complications(mainIy including postoperative hemorrhage,postoperative urine leakage,or incision areal infection,and the occurrence of low limb venous thrombosis during postoperative hospitalization).The estimated glomerular filtration rate(eGFR)before and after surgery was calculated according to the CKD-EPI creatinine-cystatin C formula and the AeGFR before and after surgery was calculated.According to the distribution patterns of clinical cases on ischemic time,clinical cases were divided into 0-15min group,15-25min group,25-35min group,and above-35min group according to renal warm ischemia time.One-Way Anova,Kruskal-Wallis test,Pearson Chi-Square Test are adopted to analyze the baseline data between groups.Using 15min,25min,35min as the cutoff value of warm ischemic time to conduct independent sample t test,and observe the changes of postoperative renal function and renal function.Use multiple linear regression analysis to study various factors that may affect the postoperative renal function of patients during NSS surgeryResults A retrospective analysis of clinical data was carried out in all patients who received NSS.Among the 220 patients with complete clinical data and meeting the inclusion criteria,in the 0-15min group,15-25min group,25-35min group,and above-35min group,except for the operation time and the length of hospital stay(both P values are 0.001)and the surgical approach(transperitoneal approach or retroperitoneal approach,P Value=0.004),other baseline data including age,BMI,preoperative creatinine,and cystatin C showed no significant statistical difference(all P values were greater than 0.05).When using multiple linear regression to compare the influencing factors of AeGFR,the NSS intraoperative warm ischemic time'P value=0.288 with no significant correlation.The only statistically significant independent factors in this study that affected AeGFR were age(P<0.001)and the diameter of the tumor(P=0.042).The independent sample t test was performed using the cutoff values of 15min,25min,and 35min as the warm ischemic time thresholds with P values of the impact results on postoperative eGFR of 0.862,0.482,and 0.278 respectively and the P values of the impact results on ? eGFR of 0.365,0.054,0.451 respectively,of no statistical difference.Conclusion The specific mechanism of renal warm ischemic injury and the recovery of normal physiological function from this injury has not been clearly established.The results of multiple linear regression analysis of this study indicate that warm ischemic time is not an independent influencing factor of renal function changes after NSS surgery.According to the characteristics of the clinical data of this study,the cutoff values of different warm ischemic time were divided and the results suggest that different thresholds of warm ischemic time did not affect the postoperative renal function and the changes of NSS perioperative renal function.Combined with the results of this study and the currently published literature,it is believed that the reasonable threshold value of renal warm ischemic time during current kidney surgery,especially NSS surgery,is still controversial,and its cutoff value can be appropriately extended,which suggests that the main effort should be exerted on the accuracy of surgery in order to retain more nephrons rather than curbing the warm ischemic time.The physiological mechanism of renal warm ischemia still needs further research. |
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