[Safety of perfused needle electrode radiofrequency ablation in the first and second portal region parenchyma in swine].

Background & Objective: When tumor invaded the hepatic portal, the difficulty of surgical resection is increased and the probability of hepatic tumor relapse is increased. Whether the perfused needle radiofrequency ablation (RFA), as a mature technique, has more advantages in the treatment of tumors involving the portal region is a hot topic in clinic. This study was to investigate the correlation of ablation time to tumor necrosis area, and observe the pathologic changes of the vessel and bile duct after application of perfused needle RFA in the first and second portal region parenchyma in swine.
Methods: Six healthy swine weighted (47.0+/-2.5) kg were treated with RFA at 60 W in 5 areas of the liver: 3 min, 5 min, and 10 min for 3 regions in different segments, 10 min for the first portal region, and 5 min for the second portal region. The swine were killed at 7-10 days after RFA. The necrosis area was measured. The pathologic changes of the vessel and bile duct were observed.
Results: In the hepatic parenchyma, the necrotic areas were oval, the length diameters of necrotic areas were (2.7+/-0.2), (4.6+/-1.1), and (5.8 +/-0.7) cm respectively when ablated for 3, 5, and 10 min. In the first and second hepatic portal regions, the width diameters of necrotic areas were (3.2+/-1.1) cm and (3.3+/-0.4) cm; no obvious damage was observed in the vessel and bile duct, but chronic inflammation was observed in the wall. In the second hepatic portal region, hepatic tissue close to the vessel wall showed complete necrosis in 5 swine and partial necrosis in 1 swine after ablation; in the first hepatic portal region, hepatic tissue close to the vessel wall showed complete necrosis in 4 swine and partial necrosis in 2 swine after ablation.
Conclusions: The necrotic area in ablated tissue is enlarged along with the duration of RFA. Ablation has little impact on the vessel and bile duct grossly and microscopically, therefore, it is safe for the hepatic portal area.