Effect of cryosurgery on liver blood flow.

The effect of cryosurgery on normal liver and liver tumour was investigated using 60 adult male rats. Animals were divided into four groups Group A implanted tumour/cryosurgery (n = 19), Group B normal liver/cryosurgery (n = 17), Group C normal liver/sham cryosurgery (n = 10) and Group D implanted tumour/sham cryosurgery (n = 14). At laparotomy animals were injected into the left lateral lobe of the liver with 10(5) HSN fibrosarcoma cells or vehicle. Two weeks after implantation red cell flux was recorded in all animals, the appropriate groups treated with cryosurgery and after thawing red cell flux was monitored over the tumour and at the edge of the cryolesion and over the corresponding normal area in controls. In certain animals red cell flux was measured at hourly intervals for 8 h, and in further groups at 24 h and at 2 weeks after cryosurgery. Results demonstrated that cryosurgery significantly reduced (P < 0.01) red cell flux in both normal and tumour liver, immediately after treatment. Red cell flux remained significantly reduced (P < 0.005) at 8 h after treatment but by 24 h had returned to preoperative levels which was maintained at 2 weeks. The results suggest that microcirculatory shutdown may be a contributing factor to the tumour necrosis occurring after cryosurgery.