Electrosurgical apparatus with stable coagulation

• US 6,511,476 B2
• Filed: 11/14/2001
• Issued: 01/28/2003
• Est. Priority Date: 11/27/1998
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Hareyama, Norihiko
• Primary Examiner(s): Dvorak, Linda C. M.
• Assistant Examiner(s): Ruddy, David M.
• Application Number:
  US09/992,457
• Publication Number:
  US 20020032439A1
• Time in Patent Office: 440 Days
• Field of Search: 606/32, 606/34, 606/38, 606/40, 606/41, 606/42, 606/46, 606/48, 606/50, 607/98, 607/101, 607/102, 607/122
• US Class Current: 606/34
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00875 Resistance or impedance

Abstract

An electrosurgical apparatus supplies high-frequency power from a high-frequency power supply unit to an instrument placed in association with an organic tissue to dissect or coagulate the organic tissue. An impedance calculating section calculates the impedance value of the organic tissue. A rate-of-impedance-change calculating section calculates the rate of impedance change of the organic tissue based on the impedance value calculated by the impedance calculating section. A control section controls the high-frequency output of the high-frequency power supply unit based on a predetermined condition provided by combining the impedance value calculated by the impedance calculating section with the rate of impedance change calculated by the rate-of-impedance-change calculating section.

Claims

1. An electrosurgical apparatus for supplying high-frequency power from a high-frequency power supply unit to an instrument placed in association with an organic tissue to dissect or coagulate said organic tissue, said electrosurgical apparatus comprising:

an impedance calculating section for calculating an impedance value or said organic tissue;

a rate-of-impedance-change calculating section for calculating a rate of impedance change of said organic tissue based on said impedance value calculated by said impedance calculating section; and

a control section for controlling a high-frequency output of said high-frequency power supply unit based on a predetermined condition provided by an evaluation of both said impedance value calculated by said impedance calculating section and said rate of impedance change calculated by said rate-of-impedance-change calculating section;

wherein said impedance calculating section acquires said impedance value by measuring a voltage and a current in said high-frequency output, and said control section detects a short-circuited state between electrodes based on said impedance value and wherein said control section detects said short-circuited state when an absolute value of a negative rate of impedance change becomes equal to or greater than a first predetermined value or said impedance value becomes equal to or smaller than a second predetermined value.

2. The electrosurgical apparatus according to claim 1, wherein said control section controls said high-frequency output of said high-frequency power supply unit when either a condition that said rate of impedance change has become equal to or greater than a first predetermined value at least once and said impedance value has become equal to or greater than a second predetermined value acquired from a function of a predetermined minimum impedance value, or a condition that said impedance value becomes equal to or greater than a sum of said minimum impedance value and a third predetermined value is satisfied.

3. The electrosurgical apparatus according to claim 2, said function of said minimum impedance value includes two different functions and they are used interchangebly in accordance with said minimum impedance value.

4. The electrosurgical apparatus according to claim 1, wherein said control section stops said high-frequency output upon detection of said short-circuited state.

5. A control apparatus, connected to an electrosurgical apparatus having an instrument for performing a predetermined treatment on an organic tissue and a high-frequency power supply unit for supplying high-frequency power for treating said organic tissue to said instrument, for controlling said high-frequency power output from said high-frequency power supply unit, said control apparatus comprising:

an impedance calculating section for calculating an impedance value of said organic tissue;

a rate-of-impedance-change calculating section for calculating a rate of impedance change of said organic tissue based on said impedance value calculated by said impedance calculating section; and

a control section for controlling a high-frequency output of said high-frequency power supply unit based on a predetermined condition provided by combining said impedance value calculated by said impedance calculating section with said rate of impedance change calculated by said rate-of-impedance-change calculating section;

wherein said impedance calculating section acquires said impedance value by measuring a voltage and a current in said high-frequency output, and said control section detects a short-circuited state between electrodes based on said impedance value and wherein said control section detects said short-circuited state when an absolute value of a negative rate of impedance change becomes equal to or greater than a first predetermined value or said impedance value becomes equal to or smaller than a second predetermined value.