Impact of temporary hilar clamping during laparoscopic partial nephrectomy on postoperative renal function: a prospective study.

PURPOSE: Laparoscopic partial nephrectomy for small renal tumors has been increasingly performed in the last few years. We prospectively evaluated preoperative and postoperative differential renal function by renal scan in patients with contralaterally functioning kidneys who underwent laparoscopic partial nephrectomy with hilar clamping.
MATERIALS AND METHODS: From July 2002 to June 2003, 17 consecutive patients were included in this prospective protocol and underwent laparoscopic partial nephrectomy for exophytic tumors using en bloc hilar clamping. Preoperative renal scan with differential function was performed 1 month before and 3 months after surgery in all patients. technetium labeled diethylenetetraminepentaacetic acid scan was performed in all patients.
RESULTS: Mean warm ischemia time was 22.50 +/- 9.78 minutes (range 10 to 44). Preoperative differential renal function and glomerular filtration rate (GFR) in the affected kidneys were 50.20% +/- 4.90% (range 43 to 58) and 75.56 +/- 16.45 ml per minutes (range 39.4 to 105). At postoperative month 3 differential renal function and GFR in the affected kidney were 48.07% +/- 7.16% (range 39% to 63%) and 72.03 +/- 18.17 ml per minutes (range 31 to 101). There was a nonsignificant negative association between hilar clamp time and change in renal function (postoperative - preoperative) of the affected kidney (r = -0.26, p = 0.31), and a positive correlation between clamp time and change in GFR (r = 0.39, p = 0.12) that did not reach statistical significance.
CONCLUSIONS: In patients with contralaterally functioning kidney, temporary hilar clamping with a mean warm ischemia time of 22.5 minutes results in preservation of renal function in the affected kidney. Larger studies with longer followup are necessary to study the impact of warm ischemia further.