US6409722B1 — Apparatus and method for creating, maintaining, a…

Claim 1

Independent Claim 254 words

An apparatus for producing, maintaining, and controlling a virtual electrode for a provision of RF current therapy through the virtual electrode to a target tissue of a body of a patient, the apparatus providing a conductive fluid and an RF current via at least one surgical instrument to the target tissue to create the virtual electrode, the apparatus comprises: a generator of RF current, the generator supplying the RF current to the virtual electrode via the surgical instrument; means for detecting an electrical arc; means for measuring the impedance of the body of the patient to the passage of the RF current; at least one primary temperature sensor for sensing the temperature at least a first predetermined location in the body of the patient; at least one source of conductive fluid selectively providing conductive fluid to the target tissue; and means for controlling a rate of application of the conductive fluid to the target tissue and for controlling a power level of the RF current, the means for controlling receiving arc detection signals from the arc detection means, impedance measurement signals from the impedance measuring means, and temperature measurement signals from the at least one temperature sensor, the power level of the RF current and the rate of conductive fluid flow controlled by the controlling means in response to changes in the measured impedance and the sensed temperature, the means for controlling discontinuing the application of RF current for a predetermined period of time upon receiving signals indicating a detection of an electrical arc.

Claim 2

Independent Claim 254 words

An apparatus for producing, maintaining, and controlling a virtual electrode for a provision of RF current therapy through the virtual electrode to a target tissue of a body of a patient, the apparatus providing a conductive fluid and an RF current via at least one surgical instrument to the target tissue to create the virtual electrode, the apparatus comprises: a generator of RF current, the generator supplying the RF current to the virtual electrode via the surgical instrument; means for detecting an electrical arc; means for measuring the impedance of the body of the patient to the passage of the RF current; at least one primary temperature sensor for sensing the temperature at least a first predetermined location in the body of the patient; at least one source of conductive fluid selectively providing conductive fluid to the target tissue; and means for controlling a rate of application of the conductive fluid to the target tissue and for controlling a power level of the RF current, the means for controlling receiving arc detection signals from the arc detection means, impedance measurement signals from the impedance measuring means, and temperature measurement signals from the at least one temperature sensor, the power level of the RF current and the rate of conductive fluid flow controlled by the controlling means in response to changes in the measured impedance and the sensed temperature, the means for controlling discontinuing the application of RF current for a predetermined period of time upon receiving signals indicating a detection of an electrical arc.

Claim 3

Dependent Claim 28 words

The apparatus of claim 1 wherein said predetermined time for discontinuing the RF power in response to the detection of an electrical arc is at least two seconds.

Claim 4

Dependent Claim 52 words

The apparatus of claim 1 and further including means for determining time and means for counting the number of arcs detected by the arc detection means, the means for controlling discontinuing the application of the RF current to the patient upon counting a predetermined number of arcs within a predetermined time period.

Claim 5

Dependent Claim 44 words

The apparatus of claim 1 and further including a clock, said clock providing time indicating signals to said means for controlling, wherein said means for controlling determining the time interval between successive changes in the maximum RF power based upon said time indicating signals.

Claim 6

Dependent Claim 32 words

The apparatus of claim 4 wherein the means for controlling maintains the current maximum RF power if a predetermined time interval has not elapsed since the most recent change to RF power.

Claim 7

Dependent Claim 47 words

The apparatus of claim 1 wherein the means for controlling determines a rate of change of the measured impedance and compares it with a predetermined impedance threshold, the means for controlling reducing the maximum RF power by a predetermined amount if such predetermined impedance threshold is exceeded.

Claim 8

Dependent Claim 75 words

The apparatus of claim 1 and further comprising: at least one secondary temperature sensor being disposed at a predetermined location in the body of the patient, wherein the at least one secondary temperature sensor provides temperature indicating signals to the means for controlling; and wherein the means for controlling compares the secondary temperature measurements with a predetermined secondary temperature threshold and discontinues the application of RF power if the predetermined secondary temperature threshold is exceeded.

Claim 9

Dependent Claim 39 words

The apparatus of claim 7 , wherein said virtual electrode substantially defines a volume of tissue to be ablated and the at least one secondary temperature sensor is placed in tissue surrounding the volume of tissue to be ablated.

Claim 10

Independent Claim 106 words

A method of treating tissue by ablation with a virtual electrode, the method comprising: placing an RF power delivery electrode within the tissue; providing the tissue with a conductive fluid to create the virtual electrode; applying RF current power to the tissue through the virtual electrode while continuing to provide conductive fluid to the tissue; monitoring an impedance of the tissue; determining a rate of change of the tissue impedance within a predetermined time interval; and increasing a size of the virtual electrode when the determined rate of change of the tissue impedance exceeds a predetermined value by increasing a flow rate of the conductive fluid.

Claim 11

Independent Claim 106 words

A method of treating tissue by ablation with a virtual electrode, the method comprising: placing an RF power delivery electrode within the tissue; providing the tissue with a conductive fluid to create the virtual electrode; applying RF current power to the tissue through the virtual electrode while continuing to provide conductive fluid to the tissue; monitoring an impedance of the tissue; determining a rate of change of the tissue impedance within a predetermined time interval; and increasing a size of the virtual electrode when the determined rate of change of the tissue impedance exceeds a predetermined value by increasing a flow rate of the conductive fluid.

Claim 12

Dependent Claim 61 words

The method of claim 9 and further including: determining a maximum impedance for the tissue to be ablated; determining an actual impedance at a specified time; comparing the maximum impedance with the actual impedance to determine if the actual impedance is greater than the maximum impedance; and reducing the applied power when the actual impedance is greater than the maximum impedance.

Claim 13

Dependent Claim 21 words

The method of claim 9 and further including adjusting the applied RF current power in response to the measured impedance change.

Claim 14

Dependent Claim 35 words

The method of claim 9 and further comprising: the step of monitoring the voltage to detect the occurrence of an electrical arc; and the step of reducing the power upon the detection of an arc.

Claim 15

Dependent Claim 25 words

The method of claim 12 and further including turning off the applied power upon the detection of an arc for a predetermined period of time.

Claim 16

Dependent Claim 65 words

The method of claim 9 , and further including: determining a maximum impedance Z max for the tissue to be ablated; determining the impedance Z 1 at a time t 1 ; comparing Z max with Z 1 to determine if Z 1 is greater or less than Z max ; and increasing the applied power when Z 1 is less than Z max .

Claim 17

Dependent Claim 15 words

The method of claim 13 , and further including counting the number of detected arcs.

Claim 18

Independent Claim 271 words

A system for producing, maintaining, and controlling a virtual electrode for a provision of RF current therapy through the virtual electrode to a target tissue of a body of a patient, the apparatus providing a conductive fluid and an RF current via at least one surgical instrument to the target tissue to create the virtual electrode, the apparatus comprises: a surgical instrument including an electrode for delivery of the RF current to the virtual electrode; a generator of RF current, the generator supplying the RF current to the virtual electrode via the surgical instrument; means for detecting an electrical arc; means for measuring the impedance of the body of the patient to the passage of the RF current; at least one primary temperature sensor for sensing the temperature at at least a first predetermined location in the body of the patient; at least one source of conductive fluid selectively providing conductive fluid to the target tissue; and means for controlling a rate of application of the conductive fluid to the target tissue and for controlling a power level of the RF current, the means for controlling receiving arc detection signals from the arc detection means, impedance measurement signals from the impedance measuring means, and temperature measurement signals from the at least one temperature sensor, the power level of the RF current and the rate of conductive fluid flow controlled by the controlling means in response to changes in the measured impedance and the sensed temperature, the means for controlling discontinuing the application of RF current for a predetermined period of time upon receiving signals indicating a detection of an electrical arc.

Claim 19

Independent Claim 271 words

A system for producing, maintaining, and controlling a virtual electrode for a provision of RF current therapy through the virtual electrode to a target tissue of a body of a patient, the apparatus providing a conductive fluid and an RF current via at least one surgical instrument to the target tissue to create the virtual electrode, the apparatus comprises: a surgical instrument including an electrode for delivery of the RF current to the virtual electrode; a generator of RF current, the generator supplying the RF current to the virtual electrode via the surgical instrument; means for detecting an electrical arc; means for measuring the impedance of the body of the patient to the passage of the RF current; at least one primary temperature sensor for sensing the temperature at at least a first predetermined location in the body of the patient; at least one source of conductive fluid selectively providing conductive fluid to the target tissue; and means for controlling a rate of application of the conductive fluid to the target tissue and for controlling a power level of the RF current, the means for controlling receiving arc detection signals from the arc detection means, impedance measurement signals from the impedance measuring means, and temperature measurement signals from the at least one temperature sensor, the power level of the RF current and the rate of conductive fluid flow controlled by the controlling means in response to changes in the measured impedance and the sensed temperature, the means for controlling discontinuing the application of RF current for a predetermined period of time upon receiving signals indicating a detection of an electrical arc.

Claim 20

Dependent Claim 28 words

The system of claim 16 wherein said predetermined time for discontinuing the RF power in response to the detection of an electrical arc is at least two seconds.

Claim 21

Dependent Claim 52 words

The system of claim 16 and further including means for determining time and means for counting the number of arcs detected by the arc detection means, the means for controlling discontinuing the application of the RF current to the patient upon counting a predetermined number of arcs within a predetermined time period.

Claim 22

Dependent Claim 44 words

The system of claim 16 and further including a clock, said clock providing time indicating signals to said means for controlling, wherein said means for controlling determining the time interval between successive changes in the maximum RF power based upon said time indicating signals.

Claim 23

Dependent Claim 32 words

The system of claim 19 wherein the means for controlling maintains the current maximum RF power if a predetermined time interval has not elapsed since the most recent change to RF power.

Claim 24

Dependent Claim 47 words

The system of claim 16 wherein the means for controlling determines a rate of change of the measured impedance and compares it with a predetermined impedance threshold, the means for controlling reducing the maximum RF power by a predetermined amount if such predetermined impedance threshold is exceeded.

Claim 25

Dependent Claim 75 words

The system of claim 16 and further comprising: at least one secondary temperature sensor being disposed at a predetermined location in the body of the patient, wherein the at least one secondary temperature sensor provides temperature indicating signals to the means for controlling; and wherein the means for controlling compares the secondary temperature measurements with a predetermined secondary temperature threshold and discontinues the application of RF power if the predetermined secondary temperature threshold is exceeded.

Claim 26

Dependent Claim 39 words

The system of claim 22 , wherein said virtual electrode substantially defines a volume of tissue to be ablated and the at least one secondary temperature sensor is placed in tissue surrounding the volume of tissue to be ablated.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2005-06-24	2005-12-24	2006-06-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2009-06-24	2009-12-24	2010-06-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2013-06-24	2013-12-24	2014-06-25	$7700.00	Window Closed / Lapsed

Apparatus and method for creating, maintaining, and controlling a virtual electrode used for the ablation of tissue

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