Electrosurgical instrument

Claim 2

An electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising: an instrument shaft, a tissue treatment electrode mounted at the distal end of the shaft for electrosurgically excising tissue pieces at an operation site, the tissue treatment electrode being movable cyclically relative to the distal end of the shaft, a vaporisation detection circuit for detecting vaporisation in the region of the tissue treatment electrode, and vaporisation control means for controlling the power threshold for vaporisation of the electrically-conductive medium at the tissue treatment electrode, in response to the output of the vaporisation detection circuit, by varying turbulence in said the electrically-conductive medium.

Claim 3

An electrosurgical instrument as claimed in claim 1 , further comprising drive means for moving the tissue treatment electrode relative to the distal end of the shaft.

Claim 4

An electrosurgical instrument as claimed in claim 2 , wherein the tissue treatment electrode is provided at the distal end of a rod mounted within, and movable relative to, the instrument shaft.

Claim 5

An electrosurgical instrument as claimed in claim 3 , wherein the tissue treatment electrode is constituted by the distal end portion of the rod.

Claim 6

An electrosurgical instrument as claimed in claim 3 , wherein drive means is such as to reciprocate the rod within the channel.

Claim 7

An electrosurgical instrument as claimed in claim 5 , wherein the drive means is constituted by a motor and coupling means for converting the rotary output of the motor into reciprocatory movement of the rod.

Claim 8

An electrosurgical instrument in claim 3 , wherein the drive means is such as to rotate the rod within a channel formed within the instrument shaft for removing matter from a region surrounding the tissue treatment electrode.

Claim 9

An electrosurgical instrument as claimed in claim 7 , wherein an electric motor constitutes the drive means.

Claim 10

An electrosurgical instrument as claimed in claim 1 , further comprising a return electrode which is electrically insulated from the tissue treatment electrode by insulation means, the tissue treatment electrode being exposed at the distal end of the instrument, and the return electrode having a fluid contact surface spaced proximally from the end of the tissue treatment electrode.

Claim 11

An electrosurgical instrument as claimed in claim 9 , wherein the tissue treatment electrode is movable cyclically relative to the return electrode so as to move the tissue treatment electrode cyclically into, and out of, at least one position in which arcing occurs between the tissue treatment and return electrodes.

Claim 12

An electrosurgical instrument as claimed in claim 9 , further comprising an RF generator having a bipolar output connected to the tissue treatment electrode and the return electrode.

Claim 13

An electrosurgical instrument as claimed in claim 11 , wherein the control means includes a vaporisation detection circuit for detecting vaporisation in the region of the tissue treatment electrode, the vaporisation detection circuit being connected to the output of the RF generator whereby the vaporisation power threshold is controlled in dependence upon the output characteristics of the RF generator.

Claim 14

An electrosurgical instrument as claimed in claim 12 , wherein the control means further includes an RF active detection circuit for detecting the presence of RF voltages at the output of the RF generator and removal means comprising a pump for aspirating matter from a region surrounding the tissue treatment electrode whereby the pump can be activated before the RF generator is turned on.

Claim 15

An electrosurgical instrument as claimed in claim 1 , wherein the control means is such as to produce turbulence in the fluid medium surrounding the tissue treatment electrode, whereby, should vaporisation of the fluid medium surrounding the tissue treatment electrode cease, the control means is effective to reduce the turbulence, thereby to allow vaporisation to be re-established.

Claim 16

An electrosurgical instrument as claimed in claim 14 , wherein the control means is such as to vary the rate of cyclical movement of the tissue treatment electrode thereby producing said turbulence in the fluid medium surrounding the tissue treatment electrode.

Claim 17

An electrosurgical instrument as claimed in claim 1 , further comprising removal means, the instrument having an apertured portion through which matter can be aspirated by the removal means from the region surrounding the tissue treatment electrode, the removal means comprising a channel formed within the instrument shaft and leading from the apertured portion.

Claim 18

An electrosurgical instrument as claimed in claim 16 , wherein the removal means further comprises a pump connected to the channel at a region thereof remote from the apertured portion of the instrument.

Claim 19

An electrosurgical instrument as claimed in claim 17 , wherein the control means is such as to vary the rate of the pump thereby producing said turbulence in the fluid medium surrounding the tissue treatment electrode.

Claim 20

An electrosurgical instrument as claimed in claim 17 , wherein the pump is activated cyclically whereby matter is aspirated by the removal means in a pulsed fashion.

Claim 21

An electrosurgical instrument as claimed in claim 17 , wherein the pump is activated only when the tissue treatment electrode is powered for tissue vaporisation.

Claim 22

An electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising: an instrument shaft, a tissue treatment electrode mounted at the distal end of the shaft for electrosurgically excising tissue pieces at an operation site, the tissue treatment electrode being movable cyclically relative to the distal end of the shaft, vaporisation threshold control means for controlling the power threshold for vaporisation of the electrically-conductive fluid medium at the tissue treatment electrode, a return electrode which is electrically insulated from the tissue treatment electrode by insulation means, the tissue treatment electrode being exposed at the distal end of the instrument, and the return electrode having a fluid contact surface spaced proximally from the end of the tissue treatment electrode, drive means for moving the tissue treatment electrode relative to the distal end of the shaft, and an RF generator having a bipolar output connected to the tissue treatment electrode and the return electrode wherein the RF generator supplies energy to the drive means, wherein said drive means is comprised of a motor.

Claim 23

An electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising: an instrument shaft, a tissue treatment electrode mounted at the distal end of the shaft for electrosurgically excising tissue pieces at an operation site, the tissue treatment electrode being movable cyclically relative to the distal end of the shaft, vaporisation threshold control means for controlling the power threshold for vaporisation of the electrically-conductive fluid medium at the tissue treatment electrode, a return electrode which is electrically insulated from the tissue treatment electrode by insulation means, the tissue treatment electrode being exposed at the distal end of the instrument, and the return electrode having a fluid contact surface spaced proximally from the end of the tissue treatment electrode, drive means for moving the tissue treatment electrode relative to the distal end of the shaft, and an RF generator having a bipolar output connected to the tissue treatment electrode and the return electrode wherein the RF generator supplies energy to the drive means, wherein said drive means is comprised of a motor.

Claim 24

An electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising: an instrument shaft, a tissue treatment electrode mounted at the distal end of the shaft for electrosurgically excising tissue pieces at an operation site, the tissue treatment electrode being movable cyclically relative to the distal end of the shaft, and vaporisation control means for controlling the power threshold for vaporisation of the electrically-conductive medium at the tissue treatment electrode by varying the rate of cyclical movement of the tissue treatment electrode to thereby vary, turbulence in said electrically-conductive medium.

Claim 25

An electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising: an instrument shaft, a tissue treatment electrode mounted at the distal end of the shaft for electrosurgically excising tissue pieces at an operation site, the tissue treatment electrode being movable cyclically relative to the distal end of the shaft, and vaporisation control means for controlling the power threshold for vaporisation of the electrically-conductive medium at the tissue treatment electrode by varying the rate of cyclical movement of the tissue treatment electrode to thereby vary, turbulence in said electrically-conductive medium.

Claim 26

An electrosurgical instrument as claimed in claim 22 wherein the vaporisation control means reduces turbulence in the electrically-conductive medium by varying the rate of movement of the tissue treatment electrode.

Claim 27

An electrosurgical instrument as claimed in claim 22 wherein the vvaporisation control means reduces turbulence in the electrically-conductive medium by reducing the speed of reciprocation of the tissue treatment electrode.

Claim 28

An electrosurgical instrument as claimed in claim 22 further comprising a pump for aspirating matter from a region surrounding the tissue treatment electrode.

Claim 29

An electrosurgical instrument as claimed in claim 25 wherein the vaporisation control means reduces turbulence in the electrically-conductive medium by varying the rate of the pump.

Claim 30

An electrosurgical instrument as claimed in claim 25 wherein the vaporisation control means reduces turbulence in the electrically-conductive medium by reducing the strength of suction delivered by the pump.

Claim 31

An electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising: an instrument shaft, a tissue treatment electrode provided at the distal end of a rod mounted within the instrument shaft for electrosurgically excising tissue pieces at an operation site, a drive means constituted by, a motor and coupling means for converting the rotary output of the motor into reciprocatory movement of the rod, the tissue treatment electrode being movable cyclically so as to be reciprocatable relative to the distal end of the shaft, and vaporisation control means for controlling the power threshold for vaporisation of the electrically-conductive medium at the tissue treatment electrode.

Claim 32

An electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising: an instrument shaft, a tissue treatment electrode provided at the distal end of a rod mounted within the instrument shaft for electrosurgically excising tissue pieces at an operation site, a drive means constituted by, a motor and coupling means for converting the rotary output of the motor into reciprocatory movement of the rod, the tissue treatment electrode being movable cyclically so as to be reciprocatable relative to the distal end of the shaft, and vaporisation control means for controlling the power threshold for vaporisation of the electrically-conductive medium at the tissue treatment electrode.

Claim 33

An electrosurgical instrument as claimed in claim 28 further comprising a return electrode electrically insulated from the tissue treatment electrode by an insulator, the tissue treatment electrode being reciprocatable relative to the return electrode so as to move the tissue treatment electrode cyclically into, and out of, at least one position in which arcing occurs between the tissue treatment electrode and the return electrode.

Claim 34

An electrosurgical instrument as claimed in claim 29 wherein the tissue treatment electrode is mounted at the distal end of a rod mounted within, and movable relative to, the instrument shaft.

Claim 35

An electrosurgical instrument as claimed in claim 30 further comprising a drive for reciprocating the rod within the instrument shaft, whereby the tissue treatment electrode is reciprocated relative to the distal end of the shaft.

Claim 36

An electrosurgical instrument as claimed in claim 31 wherein the rod is formed with a portion off-set from the longitudinal axis of the instrument shaft.