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

Abstract

Purpose: 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.

Materials and methods: 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.

Results: 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.

Conclusion: Our method is simple, effective, and reproducible.