Cellular and Vascular Reactions in the Liver to Radio-Frequency Thermo-Ablation with Wet Needle Applicators

Abstract

The aim of this animal experiment was to investigate the cellular and vascular reactions in the liver of juvenile domestic pigs produced by a radio-frequency thermoablation (RFTA) applicator perfused with saline solution. Methods: A total of 13 coagulation necroses were produced in the liver of 3 anesthetized domestic pigs using RFTA. The pigs were dissected and the coagulations examined. Results: The mean macroscopical length and width of the coagulation zones with a hemorrhagic marginal zone after a 5-minute application time were 34.1 ± 8 mm (22–46 mm) and 20.8 ± 4 mm (12 ± 28 mm) respectively. The sonographically determined diameters correlated significantly (r_length = 0.741 and r_width = 0.923). Three areas in the coagulation zones could be histologically distinguished: (1) central necrosis zone, (2) hemorrhagic marginal zone, (3) sublethal damage zone. Large vessels did not show any substantial changes after RFTA. Venous vessels less than 1 mm were completely thermally denatured or destroyed. Conclusions: Tumors in close proximity to large blood vessels can be treated by RFTA with ‘wet electrodes’.