Patent ID: 6855142
Filing Date: 2005-02-15
Classification: A61B

Abstract:
1. An electrosurgical device for treating a body tissue with a high-frequency power, comprising: an electrode for outputting a high-frequency power to the body tissue for treatment; and a high-frequency cautery power supply having a control circuit for controlling a high-frequency power generator that outputs the high-frequency power to the electrode, wherein the control circuit of the high-frequency cautery power supply comprises: a time measurement unit for measuring output time of the high-frequency power when a first high-frequency power is applied to the body tissue, from said high-frequency cautery power supply, the time measurement unit being able to set the output time to a desired output time; an impedance detector for detecting an impedance of the body tissue in the coagulated state thereof when the body tissue is treated using the high-frequency power applied from the electrode, an impedance comparator for: a) determining whether a change with the passage of time of the impedance which is detected by said impedance detector meets a predetermined condition within the output time set by the time measurement unit; and b) for comparing the impedance of the coagulated tissue detected by the impedance detector with an impedance predetermined for the purpose of the treatment of a region to be treated; and a high-frequency power switch for switching the applied first high-frequency power output of the high-frequency power generator to a second high-frequency power level when the output time set in the time measurement unit has elapsed, or, for switching the applied first high-frequency power to a third high-frequency power level when a change with the passage of time of the impedance detected by the impedance detector meets a predetermined condition within the output time as set by the time measurement unit, wherein said high-frequency power switch further switches the second or third high-frequency power level to a fourth high-frequency power level if the impedance becomes higher than the predetermined impedance after the first high-frequency power level has been switched to the second or third high-frequency power level, and wherein a volume of the body tissue subject to said high-frequency power control is determined in accordance with the output time measured and the change with the passage of time of the impedance.