Effects of radiofrequency ablation on normal lung tissue in a swine model

Abstract

Rationale and objectives: To determine the effect of radiofrequency (RF) ablation on normal lung tissue in an animal model.

Materials and methods: RF ablation of lung tissue was performed on eight swine under computed tomographic control. Group A (n = 4) received peripheral ablation (subpleural needle placement) and group B (n = 4) received central ablation (hilar needle placement). RF ablation was applied via a single 4.5-gauge internally cooled electrode with a 2-cm tip for 12 minutes. The ablation was monitored with computed tomography at 3, 7, and 12 minutes, and 10 minutes after ablation. After 3, 7, 40, and 60 days, computed tomography was performed, and the animals were sacrificed to examine the lung tissue both macroscopically and histopathologically.

Results: There were no deaths from RF ablation. In group A, coagulative necrosis was resorbed almost completely and transformed into a fibrotic scar after 60 days. No pneumothorax, pleural effusion, or lung abscess was observed. In group B, there was also a transformation of the necrosis into connective tissue. Neither the pulmonary vessels nor the bronchi of the hilum abutting the coagulative necrosis were damaged. After 60 days, no vascular thrombosis, bleeding, aneurysm, bronchial stenosis, or bronchopulmonary fistula was observed.

Conclusion: RF ablation of lung tissue affects coagulation necrosis, causing scar transformation. There was no damage to either great vessels or bronchi. The application of RF ablation for tumors located in or near functional structures appears feasible without severe complications.