LAPAROSCOPICALLY GUIDED BIPOLAR RADIOFREQUENCY ABLATION OF AREAS OF PORCINE LIVER

Background: Bipolar radiofrequency ablation (BRFA) is a promising tech nique with which to treat unresectable primary and metastatic liver tu mors. Its effects on normal liver tissue and postoperative liver funct ion, however, are unknown. We performed this study to determine (1) th e feasibility of using laparoscopic ultrasound to guide placement of B RFA needle electrodes in the liver and (2) the histopathologic, hepati c biochemical, and systemic hemodynamic responses to BRFA. Methods: Tw o BRFA lesions were created in the liver of adult domestic pigs to abl ate 8-10% of the normal liver volume. Laparoscopic ultrasound was used to guide creation of one peripheral liver lesion and one central live r lesion (with a major hepatic or portal venous vein branch in the cen ter of the BRFA lesions) in each animal. BRFA of liver tissue was perf ormed by passing 12 W of RF power for 16 min across two 16-gauge activ e-needle electrodes placed 3 cm apart. Results: All animals survived t he procedure without significant hemodynamic alterations during or aft er BRFA. All animals had a transient elevation in serum transaminase l evels that returned to normal within 1 week of the BRFA of liver tissu e. Gross and microscopic histopathology of the BRFA lesions revealed 2 .0-2.5-cm zones of complete coagulative necrosis around and between th e BRFA needle tracks without destruction of major blood vessel walls. Conclusions: This study demonstrates (1) that laparoscopic ultrasound can be used to guide placement of BRFA needles in the liver and (2) th at BRFA produces focal destruction of liver without significant system ic hemodynamic responses or alterations in liver function. Further stu dies of this technique to ablate malignant liver tumors are ongoing.