Impedance feedback monitor for electrosurgical instrument

Claim 2

An electrosurgical device having an end effector, wherein said end effector comprises: first and second opposing interfacing surfaces, said interfacing surfaces being capable of engaging tissue therebetween, said end effector being capable of receiving electrosurgical energy therein, electrically isolated first and second therapeutic poles comprised of electrically opposite therapeutic electrodes capable of conducting electrosurgical energy therethrough; and electrically isolated first and second sensing poles comprised of electrically opposite query electrodes capable of conducting electrosurgical energy therebetween; wherein at least one of said therapeutic electrodes is located on at least one of said first and second interfacing surfaces so that electrosurgical energy may be communicated between said therapeutic poles through the tissue engaged by said interfacing surfaces to electrosurgically treat the tissue; and wherein at least one of said first and second query electrode is located on at least one of said first and second interfacing surfaces so that sensing electrosurgical energy may be communicated between said sensing poles to measure an electrical parameter of said tissue between said sensing poles.

Claim 3

The electrosurgical device of claim 2 wherein a portion of at least one of said first and second interfacing surfaces comprises a ridge forming a tissue compression zone between said first and second interfacing surfaces, said end effector further comprising a plane bisecting said interfacing surfaces and said ridge; wherein said query electrodes are located on opposite lateral sides of said compression ridge with respect to said plane.

Claim 4

An electrosurgical device having an end effector, wherein said end effector comprises: first and second opposing interfacing surfaces, said interfacing surfaces being capable of engaging tissue therebetween, said end effector being capable of receiving electrosurgical energy therein, electrically isolated first and second therapeutic poles comprised of electrically opposite therapeutic electrodes capable of conducting electrosurgical energy therethrough; and electrically isolated first and second sensing poles comprised of electrically opposite query electrodes capable of conducting electrosurgical energy therebetween; wherein at least one of said therapeutic electrodes is located on at least one of said first and second interfacing surfaces so that electrosurgical energy may be communicated between said therapeutic poles through the tissue engaged by said interfacing surfaces to electrosurgically treat the tissue; and wherein at least one of said first and second query electrodes is located on at least one of said first and second interfacing surfaces so that sensing electrosurgical energy may be communicated between said sensing poles to measure an electrical parameter of said sensing electrosurgical energy delivered between said sensing poles.

Claim 5

An electrosurgical device for treating tissue during a surgical procedure, said device comprising: a surgical instrument having a tissue treating portion including an end effector adapted to engage tissue to be treated; electrically isolated first and second therapeutic poles comprised of tissue contacting first and second therapeutic electrodes adapted to receive electrosurgical energy from an energy source and capable of conducting electrical energy therebetween, at least one of said first and second therapeutic electrodes being associated with said tissue treating portion of said instrument; electrically isolated first and second query poles comprised of tissue contacting first and second query electrodes adapted to receive electrosurgical energy from an energy source and capable of conducting electrical energy therebetween, at least one of said first and second query electrodes being associated with said tissue treating portion of said instrument; an energy control signal for controlling RF energy supplied to said therapeutic electrodes; impedance measurement circuitry coupled to said query electrodes for measuring the impedance of tissue engaged by said end effector; wherein said impedance measuring circuitry is adapted to measure a minimum impedance value of tissue between the query electrodes as said tissue between the query electrodes treated with therapeutic energy by the treatment electrodes; to determine a target impedance value at which a desired tissue status is attained, said target value being a function of said minimum impedance value; and to compare measured impedance values of tissue between the query electrodes to the target impedance value and adjust said control signal when said measured impedance value exceeds said target impedance value.

Claim 6

The electrosurgical device of any one of claims 1 to 5 for use in a method of electrosurgically treating tissue.

Claim 7

The electrosurgical device of any one of claims 1 to 6, for use in an electrosurgical method comprising: engaging tissue between said surfaces; delivering therapeutic electrosurgical energy to said tissue between said therapeutic electrodes; delivering sensing electrosurgical energy to said tissue between said electrodes; measuring an electrical parameter of said sensing electrosurgical energy; determining when a desired tissue effect has occurred; and providing a signal indicating said tissue effect.

Claim 8

An electrosurgical impedance feedback control device, said device comprising: an energy control signal for controlling electrosurgical energy supplied from an energy source to one or more therapeutic electrodes associated with a tissue treating portion of a surgical instrument; impedance measurement circuitry adapted to be coupled to tissue contacting query electrodes associated with the tissue treating portion of the surgical instrument and to an energy source arranged to supply therapeutic electrosurgical energy to the one or more therapeutic electrodes associated with the tissue treating portion of the surgical instrument, wherein said impedance measurement circuitry is adapted to measure the impedance of tissue engaged by the tissue treating portion of the surgical instrument; wherein said impedance measuring circuitry comprises; a first device for determining a minimum impedance value; a target determining device coupled to said first device, for determining the target impedance value as a function of said minimum impedance value; and a first comparison device for comparing measured impedance values to said target impedance value and generating a signal indicating whether said measured impedance value exceeds said target impedance value.