Modeling bimodal vessel effects on radio and microwave frequency ablation zones.

A bench liver model is presented that separates the thermal and electrical effects of large blood vessels within radio and microwave frequency ablation boundaries. The model includes a cylindrical tissue environment with a 5 mm vessel placed parallel to and 15 mm way from either a Covidien Energy-based Devices Evident MW Ablation Percutaneous Antenna or a CoolTip RF Ablation Single Electrode Kit. An array of fiber optic thermal probes is used to monitor radial temperature profile on the vessel and non-vessel sides of the ablation zone.

Material removal mechanisms in monopolar electrosurgery.

The underlying mechanisms that cause the observed tissue differences in monopolar electrosurgery under different electrical excitation conditions have not been accurately identified to date. Without an understanding of the mechanisms behind the observed differences in tissue effect, advances in electrosurgical technology are reduced to empirical trial and error. The numerical method we present herein allows single arc events and two ensuing vaporization mechanisms and thermal damage to surrounding tissues to be modeled.