Renal tolerance to prolonged warm ischemia time in a laparoscopic versus open surgery porcine model

Purpose: To our knowledge the effects of renal warm ischemia (WI) during laparoscopic vs open surgery have not been investigated. Decreased renal blood flow during pneumoperitoneum may precondition the kidney to tolerate longer WI time. Traditionally 30 minutes has defined the limit of renal WI time in open surgery. However, recent reports show renal function recovery at WI times of 45 to 120 minutes. We assessed renal function recovery after prolonged WI during laparoscopic vs open surgery in a solitary kidney porcine model. Materials and Methods: A total of 32 female farm pigs underwent right laparoscopic nephrectomy to create a single kidney model. At 12 days later the animals were randomized into open and laparoscopic groups, each with 4 subgroups, namely 30, 60 and 90 minutes of WI, and a 90-minute control. Serum creatinine and the glomerular filtration rate were assessed preoperatively and on postoperative days 1, 3, 8 and 15. Results: There was no statistical difference in renal function between the laparoscopic and open groups. Although the early decrease in renal function (72 hours) was highest in the 60 and 90-minute WI groups, by postoperative day 15 this difference was not statistically significant. Postoperative day 15 glomerular filtration rate and serum creatinine values were not significantly different from baseline in any of the WI groups. Conclusions: We found no difference in renal function recovery when comparing laparoscopic and open WI. Although WI up to 90 minutes resulted in initial renal dysfunction, by 2 weeks postoperatively function normalized. Our results indicate that in a single kidney porcine model the renal unit can fully recover from WI times of up to 90 minutes.