Cryonecrosis of normal and tumor- bearing rat liver potentiated by inflow occlusion

Abstract

Cryosurgery involving large portions of rat liver with and without inflow occlusion was generally well tolerated. Tumors were successfully eradicated in 8 of 10 (80%) animals with rapidly enlarging hepatic tumor implants. Necrosis of liver parenchyma was localized and reproducible histologically. No hemorrhage or bile leakage was encountered in the target area or in adjacent untreated liver. SGOT and SGPT values rose transiently after treatment and reflected directly the extent of cryonecrosis. The magnitude of the cold insult and, hence, the volume of histologic cryonecrosis were not predictable by the size of the iceball at the time of freezing, but were affected by the rate and depth of freezing and the duration of thawing. Rapid freezing and slow thawing are maximally lethal. The cold insult was increased by the addition of two and three freezes (repetitive freezing) and was enhanced by ischemia as indicated by regional temperature measurements using thermocouples.