УМЕНЬШЕНИЕ РАЗМЕРОВ ЭКСПЕРИМЕНТАЛЬНЫХ КИСТ ПЕЧЕНИ С ПОМОЩЬЮ РАДИОЧАСТОТНОЙ АБЛЯЦИИ

Radiofrequency ablation can achieve a significant reduction of simple liver cysts. The aim of the study was to investigate the effects of RFA in various regimes on the wall of the liver cyst and adjacent tissue, and to define optimal exposure parameters. Materials and methods. An experimental study was performed by constructing of imitational models of a simple liver cyst (group № 1), a biliary cyst (group № 2), and a cyst with high electrical conductivity content (10% NaCl solution) -group № 3. The models were exposed to RFA in the range of temperatures from 50 to 92 °C with duration from 1 to 5 minutes. Then, the postablation changes of the preparations were assessed using histological examination. Results. In all groups, when heated, there was a lag of the temperature of the cystic medium compared with the temperature of the electrode. For models of group № 1, № 2, and № 3, the difference was 19.6 °C, 8.75 °C, and 3.8 °C, respectively. Coagulation necrosis was found in all preparations and was most pronounced in the surface layers of the tissue contacted with the heated medium. The absence of destruction of the adjacent liver tissue in group № 1 was found for RFA in regimes using 61-63 °C for 2 minutes; in group 2 - using 65-75 °C for 3 minutes; in group 3 - using 85 °C (for 2 minutes) or 53-55 °C (for 5 minutes). Conclusion. The destruction of all epithelial cells is achievable with RFA; however, the thermal range between total ablation and the thermal injury of adjacent healthy tissue is narrow. The introduction of 10% NaCl solution can increase the area of necrosis and makes possibility to control the temperature of the cyst. Achieving mild ablation with shallow penetration of necrosis is influenced by the volume and electrical conductivity of the cystic content, adequate control of the temperature in the cystic cavity, and dosed use of RFA power and exposure time.