Prolonged Cold Ischemia Time for Laparoscopic Partial Nephrectomy with a New Cooling Material: Freka-Gelice—A Comparison of Four Cooling Methods

Abstract

It is well known that hypothermia protects renal tissue from ischemic damage. So far, no standardized cooling method for laparoscopic surgery has been established. The traditionally used cooling method during open partial nephrectomy (OPN) is crushed ice applied around the kidney; for laparoscopic use, transarterial and transureteral perfusion cooling are described. We compared these three cooling methods with Freka-Gelice (FG), a new gel-like cooling material, and present our initial preliminary results in an ex-vivo porcine model. To prove cooling effectiveness, FG was compared with superficial crushed ice (NaCl-ice), with transureteral perfusion (TUP), and with transarterial perfusion (TAP) cooling in ex-vivo porcine kidneys. The temperature decrease over 120 minutes and practical application were evaluated. No significant difference was found for the mean value distribution at different time points for NaCl-ice and FG (P = 0.18). TUP and TAP showed insufficient temperature decrease. Mean temperatures for NaCl-ice and FG were 4.75 degrees C and 7.02 degrees C at 30 minutes, 0.72 degrees C and 2.47 degrees C at 60 minutes, and -0.19 degrees C and 2.35 degrees C at 120 minutes, respectively. FG was easy to use because of its gel-like consistence. TUP and TAP did not provide a fast and sufficient temperature decrease for renal hypothermia in this ex-vivo model. FG shows sufficient cooling qualities comparable with conventionally used NaCl-ice. Because of its gel-like consistence, FG can be used for laparoscopic partial nephrectomy, because insertion through a trocar is possible.