Laparoscopic renal cryotherapy in swine: Comparison of puncture cryotherapy preceded by arterial embolization and contact cryotherapy

Variable results of open, percutaneous, and laparoscopic cryosurgery of the kidney have been reported, Minimally invasive approaches to lower-pole ren al ablation were prospectively compared in swine: laparoscopic puncture cry oablation preceded by arterial embolization, laparoscopic contact cryosurge ry, and arterial embolization alone. Eighteen kidneys in nine domestic pigs mere randomized to one of three treatment groups of six organs each: (1) p uncture cryotherapy preceded by selective lower-pole arterial embolization; (2) contact cryotherapy alone; and (3) arterial embolization alone. Under general anesthesia, appropriate animals underwent selective arterial emboli zation of the lower pole via femoral cutdown using Gelfoam pledgets, Animal s randomized to cryotherapy underwent dissection of the lower pole of the k idney using a single 12-mm umbilical and two midclavicular-line ports in th e lateral position, Under external ultrasound guidance, two 3-mm cryoprobes (Cryomedical Sciences, Rockville, MD) were positioned in the lower pole of the kidney, and double-freeze technique to -190 degrees C was performed us ing puncture or contact application. Ultrasonography was used to guide prob e insertion during puncture cryotherapy only, Kidneys were harvested 11 to 14 days after the procedure, Both puncture and contact kidneys demonstrated cell death and subsequent necrosis by light microscopy and electron microg raphy, On average, puncture lesions were heavier than contact lesions, 19.3 g v 10.1 g (P = 0.02; unpaired t-test), whereas the kidneys were equivalen t in weight: 74.1 g v 74.1 g, Puncture lesions represented 26.4% of total k idney weight v 13.5% in the contact group (P = 0.002; unpaired t-test), Onl y focal infarcts were identified in the embolization group, No evidence of adjacent visceral injury was identified in any of the groups, and no animal required conversion to open laparotomy, One kidney bled after contact cryo therapy, and hemostasis was achieved laparoscopically. Laparoscopic cryothe rapy is reproducible and effective using either the puncture technique prec eded by arterial embolization or the contact technique, without evidence of damage to adjacent structures. Contact lesions were less voluminous and mo re peripheral than puncture lesions, Embolization alone produces focal infa rcts and focal zones of cell death.