The loop electrode: A new device for US-guided interstitial tissue ablation using radiofrequency electrosurgery - an animal study

Summary

In an animal study, we have tested a special loop electrode for ultrasound-guided percutaneous interstitial tissue ablation using monopolar radiofrequency (RF) electrosurgery. The loop electrode with a radius of 1 cm was inserted into calf livers via an insulated introducer cannula. Monopolar RF current in the cut mode was applied to the loop electrode which was rotated a full turn. During this, a lesion was cut off interstitially. In three sedated calves a total of seven liver lesions were made percutaneously or during laparotomy. The procedure was guided and monitored by ultrasono-graphy including colour Doppler imaging. Autopsy was performed on day 0 or day 8 post treatment and included gross sectional examination and microscopic evaluation (light microscopy and electron microscopy). In the first animal, the lesions were incomplete because of insufficient voltage setting. In the second and third animal, however, four spherical lesions with a diameter of 2 cm were cut off without clinical complications. A minor haematoma surrounded the four lesions. The cut off lesion was non-vital on electron microscopy. The presented tissue ablation technique is shown to be feasible and efficient in a live organism. More animal studies are warranted to evaluate the safety aspects with this technique.