Patent ID: 8062290
Filing Date: 2011-11-22
Classification: A61B

Abstract:
1. A system for heat ablation of tissue in a patient comprising: a radiofrequency source configured to supply radiofrequency energy to at least two electrodes for treating tissue; at least one return electrode configured to return the radiofrequency energy to the radiofrequency source; a controller configured to sequentially apply the radiofrequency energy to each of the at least two electrodes for a pre-determinable period of time, wherein the pre-determinable period of time is determined by a surgical procedure or the number of electrodes, the controller further including: current and voltage measuring circuitry operably connected to at least one of the at least two electrodes, wherein an impedance is calculated based on the measured current and voltage; and circuitry that restricts the flow of radiofrequency energy to at least one of the at least two electrodes when the calculated impedance exceeds a threshold impedance and that allows the flow of radiofrequency energy to at least one of the at least two electrodes when the calculated impedance does not exceed a threshold impedance, wherein the threshold impedance relates to a baseline impedance and a predetermined differential impedance wherein the predetermined differential impedance is about 30 ohms if the baseline impedance is less than about 100 ohms.