Is renal warm ischemia over 30 minutes during laparoscopic partial nephrectomy possible? One-year results of a prospective study.

OBJECTIVE: To evaluate renal damage and impairment of renal function 1 yr after laparoscopic partial nephrectomy (LPN) with warm ischemia >30 min.

METHODS: From July 2004 to June 2005, 18 patients underwent LPN with warm ischemia time >30 min. Kidney damage markers (daily proteinuria and tubular enzymes) and renal function (serum creatinine, cystatin C, and creatinine clearances) were assessed on postoperative days 1 and 5 and at 12 mo. Glomerular filtration rate (GFR) was evaluated before surgery and at 3 mo. Renal scintigraphy was performed before the procedure, at 5 d and at 3 and 12 mo postoperatively. Statistical analysis was performed using the Student t test and logistic regression analysis.

RESULTS: In terms of kidney damage and renal function markers, the statistical analysis demonstrated that at 1 yr there was complete return to the normal range and no statistical difference between the values at the various time points. The GFR was not significantly different before and 3 mo after surgery. In terms of scintigraphy of the operated kidney, the values were 48.35+/-3.82% (40-50%) before the procedure, 36.88+/-8.42 (16-50%) on postoperative day 5 (p=0.0001), 40.56+/-8.96 (20-50%) at 3 mo (p=0.003), and 42.8+/-7.2% (20-50%) 1 yr after surgery (p=0.001).

CONCLUSION: Our results demonstrate that kidney damage occurs during LPN when warm ischemia is >30 min. This damage is only partially reversible and efforts should be made to keep warm ischemia within 30 min.