Effects of deep low temperature on secondary branches enclosed in Glisson's system of pig hepatic lobes.

BACKGROUND: Hepatic cryosurgery, a safe and effective approach for an unresectable hepatoma, has been extensively applied in clinical setting. But whether direct deep freezing to the tumor involving special location, i.e., Glisson's system of certain hepatic lobe could cause the impairment of the duct system or post impairment effect remains a mystery. Consequently, the aim of the study was to investigate the effect of freezing on the secondary branches enclosed in the Glisson's system of certain hepatic lobes. METHODS: Twenty pigs were divided into 2 groups randomly. The treated group: the area of secondary branches of the Glisson's system in the left lateral lobe was frozen by a cryoprobe at deep low temperature for 3 minutes, with the blockage of blood flow from the porta hepatis. The control group: only the blockage of the porta hepatis was performed for 3 minutes. Serologic examinations, color Doppler examination and pathological observation were used for evaluation of this procedure postoperatively. RESULTS: The frozen hepatic parenchyma, the wall of the frozen secondary bile duct and portal vein showed necrosis. However, the frozen hepatic artery ramification did not show any obvious changes postoperatively. Eight weeks after cryosurgery, the lumen of the hepatic artery and portal vein maintained unobstructed. Meanwhile, atrophy and fibroplasia occurred in the related hepatic lobe. All the animals recovered well. CONCLUSIONS: Animals could tolerate the direct deep-freezing of the area of secondary branches enclosed in the Glisson' s system. The therapeutic effect could be attained by the necrosis of the frozen hepatic parenchyma.