Patent ID: 8133218

Claim:
An electrosurgical tissue cutting system comprising: a. an RF generator configured to facilitate generation of an RF signal having RF energy, the RF generator having a start mode with the RF energy at a first duty cycle and a first RF power output and a cutting mode with the RF energy at a second duty cycle and a second RF power output lower than the first RF power output; b. an electrosurgical tissue cutting electrode configured to be in electrical communication with the RF generator to receive the RF energy and configured to engage tissue; c. a filter configured to separate a DC potential from the RF signal; d. a monitor configured to detect the separated DC potential; and e. a control unit configured to be responsive to the detected DC potential for controlling the output of the RF generator in delivering the RF energy, the control unit being configured to maintain the start mode when the detected DC potential is less than a predetermined level that forms a conductive plasma on the tissue cutting electrode and the control unit being configured to switch to the cutting mode to cut tissue when the DC potential is at or exceeds the predetermined level to form the conductive plasma.