Electrocautery method and apparatus

Abstract

An electrode structure and a mechanism for automated or user-selected operation or compensation of the electrodes, for example to determine tissue coverage and/or prevent arcing between bottom electrodes during electrocautery is disclosed.

1 . An electrocautery apparatus, comprising:
 a plurality of first electrodes forming a first electrode array;   at least one second electrode;   a power supply having multiple, independently adjustable output channels for application of high frequency power to targeted tissue via selective coupling of said high frequency power to said first electrodes and to said at least one second electrode;   at least one sensor for sensing at least one parameter comprising any of voltage, current, impedance, phase angle between applied voltage and current, temperature, energy, and frequency and for producing an output representative of a value or rate of change of said at least one parameter;   means, responsive to said at least one sensor, for controlling at least one aspect of said high frequency power provided by said power supply; and   means for selectively applying said high frequency power provided by said power supply between two or more electrodes among any of the electrodes in the first electrode array and said at least one second electrode;   wherein said high frequency power provided by said power supply cauterizes or necroses tissue between surfaces of said first electrode array and said at least one second electrode.   
     
     
         2 . The apparatus of  claim 1 , wherein said power supply is adjustable by any of real-time control, pre-set selection by a user, default settings, or selection of a predetermined profile. 
     
     
         3 . The apparatus of  claim 1 , further comprising:
 means for determining the area of tissue coverage of at least one of any of said first electrodes and said at least one second electrode by measuring phase-angle of RF voltage and current.   
     
     
         4 . The apparatus of  claim 1 , said power generating high frequency power in frequency bands comprising any of 100 kHz to 10 MHz or 200 kHz to 750 kHz. 
     
     
         5 . The apparatus of  claim 1 , said power generating high frequency power at power levels comprising any of 10 W to 500 W, or 25 W to 250 W, or 50 W to 200 W. 
     
     
         6 . The apparatus of  claim 1 , said power supplying high frequency power to said first electrodes and said at least one second electrode at power levels comprising any of 1 W/cm 2  to 500 W/cm 2  or 10 W/cm 2  to 100 W/cm 2 . 
     
     
         7 . The apparatus of  claim 1 , said sensor comprising any of:
 a voltmeter, analog-to-digital converter, thermistor, transducer, or ammeter.   
     
     
         8 . The apparatus of  claim 1 , said means for controlling said high frequency power provided by said power supply further comprising:
 means for selecting impedance to maintain an impedance match between said power supply and said tissue to achieve maximum power transfer and to make accurate power measurements;   wherein impedance matching is achieved when the phase-angle between applied voltage and current is at or near zero.   
     
     
         9 . The apparatus of  claim 8 , said means for controlling said high frequency power provided by said power supply further comprising:
 an inductive element that is adjustable to a near zero phase angle to increase inductance and compensate for increased capacitive reactance.   
     
     
         10 . The apparatus of  claim 1 , said power supply comprising adjustment means for any of:
 identifying individual electrodes to be activated to focus energy of the individual electrodes on a specific region of tissue;   establishing a firing order for said individual electrodes;   assessing or measuring magnitude of impedance to be used in compensating and/or impedance matching between said power supply and said at least one of any of said first electrodes and said at least one second electrode;   establishing at least one parameter of electrical power to be applied in electrocautery, said parameters comprising voltage, current, impedance, phase angle between applied voltage and current, temperature, energy, frequency, and/or rate of change of said at least one parameter.   
     
     
         11 . The apparatus of  claim 1 , wherein said at least one sensor is constructed to provide raw data to said means for controlling said high frequency power provided by said power supply, said means for controlling said high frequency power provided by said power supply comprising means for analyzing whether and how to adjust impedance by changing the frequency of RF energy delivered by said power supply. 
     
     
         12 . The apparatus of  claim 1 , said means for controlling said high frequency power provided by said power supply, in conjunction with said at least one sensor, further comprising:
 means for determining whether or not tissue is present at each electrode at the beginning of a cauterization cycle by measuring any of voltage, current, impedance, phase angle between applied voltage and current, temperature, energy, frequency, and/or rate of change of said at least one parameter;   wherein, if tissue is not present at any electrode, then said electrode is idle;   wherein said means for controlling said high frequency power provided by said power supply comprises means that deactivates firing of said idle electrode, and/or provides a warning to an operator via a user interface.   
     
     
         13 . The apparatus of  claim 11 , said means for controlling said high frequency power provided by said power supply further comprising:
 a status indicator for each electrode that indicates any of an idle, active, or complete condition, once a cauterization cycle is commenced with regard to each said electrode.   
     
     
         14 . The apparatus of  claim 1 , wherein said at least one second electrode comprises at least one return electrode. 
     
     
         15 . The apparatus of  claim 2 , said power supply comprising:
 an RF generator selectively operable by said means for selectively applying a voltage from the power supply to insert a conjugate impedance in the form of an inductance to cancel out capacitive reactance with a fully covered electrode and to permit measurement of phase-angle of RF voltage and current;   wherein when an electrode is only partially covered, capacitance changes; and   wherein, as a result, reactance and phase-angle of RF voltage and current change.   
     
     
         16 . The apparatus of  claim 2 , said means for selectively applying a voltage from the power supply further comprising:
 an RF generator control algorithm for changing RF generator frequency upon detection of smaller electrode surface areas to maintain maximum power transfer while minimizing electrical arcing and suboptimal and/or excessive energy delivery.   
     
     
         17 . The apparatus of  claim 1 , said means for selectively applying a voltage from the power supply further comprising:
 means for detecting electrical arcing and preventing suboptimal and/or excessive energy delivery by determining rapid changes in phase and/or impedance.   
     
     
         18 . The apparatus of  claim 3 , means for detecting electrical arcing and preventing suboptimal and/or excessive energy delivery further comprising:
 means for using electrodes which are only partially covered by tissue to signal said RF generator control algorithm to shorten or change treatment parameters.   
     
     
         19 . The apparatus of  claim 15 , said means for selectively applying a voltage from the power supply further comprising:
 means for maintaining an impedance match between said RF generator and tissue;   wherein impedance matching is achieved when a phase-angle is about zero.   
     
     
         20 . The apparatus of  claim 19 , said means for maintaining an impedance match between said RF generator and tissue further comprising:
 one or more reactive elements which compensate for increased capacitive reactance.   
     
     
         21 . The apparatus of  claim 20 , said means for maintaining an impedance match between said RF generator and tissue further comprising any of:
 means for insertion of a continuously variable inductor with a finite range and nearly infinite resolution, wherein said inductor adjustable to a near zero phase;   means for insertion of discrete elements to find a lowest phase; and   means for changing the frequency of said RF generator, wherein said RF generator compensates for phase discrepancy by electronically changing frequency.   
     
     
         22 . The apparatus of  claim 1 , said power supply further comprising a pulse width modulation mechanism for establishing a desired power output. 
     
     
         23 . An electrocautery method, comprising the steps of:
 forming a first electrode array with a plurality of first electrodes;   providing at least one second electrode;   selectively applying high frequency power to targeted tissue by coupling high frequency power to said first electrodes and to said at least one second electrode from a power supply having multiple, independently adjustable output channels;   sensing at least one parameter comprising any of voltage, current, impedance, phase angle between applied voltage and current, temperature, energy, and frequency and for producing an output representative of a value or rate of change of said at least one parameter; and   responsive to said output representative of a value or rate of change of said at least one parameter, controlling at least one aspect of said high frequency power provided by said power supply;   wherein said high frequency power provided by said power supply cauterizes or necroses tissue between surfaces of said first electrode array and said at least one second electrode.