Electrosurgical instrument

An electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising

• a semi-flexible instrument shaft capable of being used to exert firm pressure against tissue being treated by said instrument, and
• an electrode assembly at one end of the shaft, the electrode assembly comprising
• a tissue treatment electrode,
• a return electrode, and
• an insulation member electrically insulating the return electrode from the tissue treatment electrode,
• the tissue treatment electrode having an exposed end extending laterally through a cut-out provided in the insulation member,
• wherein the return electrode has a distal end portion with a fluid contact surface which overlies the insulation member in the cut-out's region and faces laterally in a first direction, and wherein the insulation member projects laterally outwardly between said distal end portion and the tissue treatment electrode,
• the tissue treatment electrode facing laterally in a second direction opposite to said first direction, and wherein the treatment electrode and the return electrode are configured in an immovable relationship to one another and the instrument shaft.

An electrode unit for an electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the electrode unit comprising

• a semi-flexible shaft having at one end means for connection to an instrument handpiece,
• and, mounted on the other end of the shaft,
• an electrode assembly comprising
• a tissue treatment electrode,
• a return electrode, and
• an insulation member electrically insulating the return electrode from the tissue treatment electrode,
• the tissue treatment electrode having an exposed end extending laterally through a cut-out provided in the insulation member, and
• the return electrode having a fluid contact surface which overlies the insulation member in the cut-out's region, said fluid contact surface being spaced from the tissue treatment electrode in such a manner as to define, in use, a conductive fluid path that completes an electrical circuit between the tissue treatment electrode and the return electrode, and
• wherein the treatment electrode and the return electrode are configured in an immovable relationship to one another and the shaft, the shaft being capable of being used to exert firm pressure against tissue being treated by the instrument.

An electrode unit for an electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the electrode unit comprising

• a semi-flexible metal shaft capable of being used to exert firm pressure against tissue being treated by the instrument, said shaft having at one end means for connection to an instrument handpiece, and, mounted at the other end,
• an electrode assembly comprising
• a tissue treatment electrode,
• a return electrode, and
• an insulation member electrically insulation the return electrode from the tissue treatment electrode,
• the tissue treatment electrode having an exposed end extending laterally through a cut-out provided in the insulation member,
• wherein the return electrode has a distal end portion with a fluid contact surface which overlies the insulation member the cut-out's region and faces laterally in a first direction, and wherein the insulation member projects laterally outwardly between said distal end portion and the tissue treatment electrode, the tissue treatment electrode facing laterally in a second direction opposite to said first direction,
• and wherein the treatment electrode and the return electrode are configured in an immovable relationship to one another and the shaft.

Electrosurgical apparatus comprising a radio frequency generator and an electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising

• a semi-flexible instrument shaft, and
• an electrode assembly at one end of the shaft, the electrode assembly comprising
• a tissue treatment electrode,
• a return electrode, and
• an insulation member electrically insulating the return electrode from the tissue treatment electrode,
• the tissue treatment electrode having an exposed end extending laterally through a cut-out provided in the insulation member at the distal end portion of the instrument,
• the return electrode having a fluid contact surface which overlies the insulation member in the cut-out's region, and
• the radio frequency generator having a bipolar output connected to the electrodes,
• said fluid contact surface being spaced form the tissue treatment electrode in such a manner as to define, in use, a conductive fluid path that completes an electrical circuit between the tissue treatment electrode and the return electrode
• the semi-flexible shaft allowing firm pressure to be exerted against tissue being treated by the instrument, the treatment electrode and the return electrode being configured in an immovable relationship to one another and the shaft.

Electrosurgical apparatus comprising a radio frequency generator and an electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising a semi-flexible instrument shaft capably of being used to exert firm pressure against tissue being treated by the instrument, and an electrode assembly at one end of the shaft, the electrode assembly comprising

• a tissue treatment electrode,
• a return electrode, and
• an insulation member electrically insulating the return electrode from the tissue treatment electrode,
• the tissue treatment electrode having an exposed end extending laterally through a cut-out provided in the insulation member,
• wherein the return electrode has a distal end portion with a fluid contact surface which overlies the insulation member in the cut-out's region and faces laterally in a first direction, and wherein the insulation member projects laterally outwardly between said distal end portion and the tissue treatment electrode, the tissue treatment electrode facing laterally in a second direction opposite to said first direction,
• and wherein the treatment electrode and the return electrode are configured in an immovable relationship to one another and the instrument shaft.

An electrosurgical method using an electrosurgical apparatus having at least a tissue desiccation mode and a tissue vaporisation mode, the apparatus having a radio frequency generator coupled to an electrode assembly for the treatment of tissue in the presence of an electrically-conductive fluid medium, the electrode assembly comprising a tissue treatment electrode, a return electrode, and an insulation member electrically insulating the return electrode from the tissue treatment electrode, the tissue treatment electrode having an exposed end extending laterally through a cut-out provided in the insulation member at distal end of the assembly, and the return electrode having a fluid contact surface spaced from the exposed end of the tissue treatment electrode by the insulation member, the treatment electrode and the return electrode being configured in an immovable relationship to one another;

• the method comprising the steps of:
• introducing the electrode assembly into a selected operation site with the issue treatment electrode adjacent to the tissue to be treated;
• immersing the fluid contact surface of the return electrode and the exposed end of the tissue treatment electrode in electrically-conductive fluid;
• and
• controlling the output power of the radio frequency generator to lie within a first output range for the tissue desiccation mode and to lie within a second range for the tissue vaporisation mode, the first output range being such that the power supplied to the electrode assembly maintains the conductive fluid adjacent to the tissue treatment electrode substantially at boiling point for tissue desiccation without creating a vapour pocket surrounding the tissue treatment electrode, and the second output range is such that the output power supplied to the electrode assembly for vaporisation of tissue is such as to maintain a vapour pocket surrounding the tissue treatment electrode.

An electrosurgical instrument for the treatment of tissue in the presence of an electrically-conductive fluid medium, the instrument comprising:

• a semi-flexible instrument shaft capable of being used to exert firm pressure against tissue being treated by said instrument,
• a suction pump for removing vapour bubbles via the instrument shaft's interior, and
• an electrode assembly at one end of the shaft, the electrode assembly comprising
• a tissue treatment electrode,
• a return electrode, and
• an insulation member electrically insulating the return electrode from the tissue treatment electrode,
• the tissue treatment electrode having an exposed end extending laterally through a cut-out provided in the insulation member at a distal end portion of the instrument, and
• the return electrode having a fluid contact surface which overlies the insulation member in the region of the cut-out, said fluid contact surface being spaced from the tissue treatment electrode in such a manner as to define, in use, a conductive fluid path that completes an electrical circuit between the tissue treatment electrode and the return electrode,
• and wherein the treatment electrode and the return electrode are configured in an immovable relationship to one another and the instrument shaft.