Renal Hypothermia During Partial Nephrectomy

The Objective is to determine if renal hypothermia during open partial nephrectomy results in improved post-operative renal function compared to warm ischemia. Primary Aim is to determine the effect of hypothermia on preservation of overall renal function compared to no hypothermia in patients who require hilar vessel clamping during open partial nephrectomy for a renal tumor. Hypothesis: Hypothermia will result in improved post-operative preservation of overall renal function. Secondary Aim is to determine the effect of hypothermia on preservation of affected renal function (kidney with the tumor) compared to no hypothermia in patients who require hilar vessel clamping during open partial nephrectomy for a renal tumor. Hypothesis: Hypothermia will result in improved post-operative preservation of affected renal function.