Second prize: simple method for achieving renal parenchymal hypothermia for pure laparoscopic partial nephrectomy

We describe the development of an innovative device and simple technique for achieving renal parenchymal hypothermia during temporary renal-vascular occlusion for pure laparoscopic partial nephrectomy.

The experiment was conceived in four phases: phase 1: design, manufacture, and testing of the cooling coil; phase 2: proof of concept in nonsurvival porcine surgery; phase 3: experimental porcine survival surgery; and phase 4: human trials.

Phase 1 testing confirmed that the coil cooled adequately. During phase 2, the average time required for the renal parenchyma to cool to 15 degrees C was 10.7 minutes, providing an average hypothermic window (15 degrees -24 degrees C) of 30.3 minutes. When recooling was required (parenchymal temperature 24 degrees C), temperatures returned to below 15 degrees C in 3 minutes. The core body temperature dropped an average of 1.48 degrees C. Phase 3 demonstrated an average parenchymal temperature of 11.7 degrees C after a mean cooling time of 9.3 minutes. Temperatures remained below 24 degrees C for an average of 26.7 minutes. Recooling took 3 minutes, and in no procedure did the renal parenchyma temperatures ever return to >24 degrees C prior to reperfusion. The core body temperature dropped an average of 2.20 degrees C. At 48 hours after reperfusion, selective renal-vein blood was obtained for creatinine assay, and the kidneys were harvested. Creatinine results were not statistically different in the treated and control groups. Blinded pathologic analysis confirmed a protective effect using our cooling system.

Our method is simple, effective, and reproducible.