Abstract: A tissue treatment system has a radio frequency generator and a handheld treatment instrument that generates a gas plasma jet for delivering thermal energy to a tissue surface to be treated. Incorporated in the housing for the generator is a calibration device for adjusting the energy output of the generator, if necessary, at the beginning of a treatment session. The calibration device has a target element with a target surface, a transducer for sensing changes in temperature of the target element with respect to the temperature of a reference element, and an energy output adjuster for adjusting the radio frequency energy output of the generator in response to a calibration signal generated by the transducer. The generator housing has a receptacle for locating the nozzle of the handheld instrument in juxtaposition with the target element so that when a plasma burst is generated as part of a calibration sequence it is incident on the target surface.

Abstract: In an electrosurgical generator for generating radio frequency power, the generator comprises a radio frequency output stage having three or more output connections, one or more sources of output power coupled to the output stage, and a controller operable to cause the generator to supply a first cutting RF waveform to the output connections or a second coagulating RF waveform to the output connections. In a combined mode, the controller causes the generator to deliver both first and second RF waveforms, the controller including means for feeding the waveforms to the output connections such that the first RF waveform is delivered between a first pair of the output connections, and the second RF waveform is delivered between a second pair of the output connections. The combined mode is adjustable between various settings, each setting having a different proportion of the first and second RF waveforms.

Abstract: A method for skin treatment comprises the steps of delivering at least one pulse of radio frequency power to at least one electrode in order to create an electric field; passing gas through the electric field in order to form plasma from the gas; and applying the plasma to the surface of skin. The amount of radio frequency power may be relatively low such that the application of plasma causes denaturation of collagen within the collagen-containing tissue beneath the skin surface, which may promote the generation of new collagen within the collagen-containing tissue.

Abstract: A bipolar electrosurgical instrument comprises a handle (5), a body (1) joined to the handle, and a jaw assembly (12) joined to the body and arranged such that manipulation of the handle allows the opposed jaws of the jaw assembly to be opened and closed with respect to one another. A first of said opposed jaws (14) has at least a first coagulating electrode, and the other of said opposed jaws (13) has at least a second coagulating electrode and a cutting electrode (16) separated from the second coagulating electrode by an insulating member (17). The instrument is manipulated at the surgical site such that the jaws of the jaw assembly (12) are open with respect to one another, with the cutting electrode (16) and at least one of the first and second coagulating electrodes contacting tissue at the surgical site.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporization or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning. In a blended mode, the output voltage is alternately limited to a value appropriate for coagulation and a value appropriate for cutting or vaporization.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporisation or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporization or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning. In a blended mode, the output voltage is alternately limited to a value appropriate for coagulation and a value appropriate for cutting or vaporization.

Abstract: An electrosurgery system for electrosurgically cutting or vaporising living tissue includes an electrosurgical generator having a pair of output terminals coupled to an electrosurgical instrument containing an electrode assembly. The electrode asssembly has at least one treatment electrode and an adjacent return electrode. The generator and the assembly are arranged to deliver to the treatment and return electrodes radio frequency (r.f.) energy individually or simultaneously at at least two frequencies, one of which is below 100 MHz and the other of which is above 300 MHz. The generator includes a load-responsive control circuit which, in one mode, causes power to be generated predominantly at the lower frequency when the load impedance is high and predominantly at the upper frequency when it is low. This allows automatic switching between cutting and coagulation operation. In another embodiment the r.f.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporization or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporization or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam Generation. The same peak voltage limitation technique is used in a tissue vaporisation or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning.

Abstract: An electrosurgical instrument is disclosed for the treatment of tissue in the presence of an electrically-conductive fluid. The instrument comprises an instrument shaft, and a tissue treatment electrode at one end of the shaft, the tissue treatment electrode being constructed to define a plurality of pockets for trapping electrically-conductive fluid. Alternatively, the tissue treatment electrode is made from an electrically-conductive material and is coated with a resistive inert material which is effective to increase the local power density within the tissue treatment electrode.

Abstract: An electrosurgical instrument, which is used to treat tissue in the presence of an electrically-conductive fluid, comprises an instrument shaft and an electrode assembly at one end of the shaft. The electrode assembly comprises a tissue treatment electrode (11) and a return electrode (12) which is electrically insulated from the tissue treatment electrode by means of an insulation member (15). The tissue treatment electrode (11) is exposed at the extreme distal end of the instrument, and the return electrode (12) has a fluid contact surface spaced from the exposed end of the tissue treatment electrode by the insulation member (15). The instrument further comprises feed means (17) for feeding electrically-conductive fluid to the region of the exposed end of the tissue treatment electrode (11) in such a manner as to define, in use, a conductive fluid path that completes an electrical circuit between the tissue treatment and the return electrode (12).

Abstract: An electrosurgical instrument is disclosed for the treatment of tissue in the presence of an electrically-conductive fluid. The instrument comprises an instrument shaft, and a tissue treatment electrode at one end of the shaft, the tissue treatment electrode being constructed to define thermal barriers for limiting thermal conduction therealong, thereby to encourage the formation and maintenance of a layer of vapor over the electrode.

Abstract: An electrosurgical instrument primarily intended for so-called "underwater" electrosurgery has a radio frequency generator, a handpiece, and an electrode assembly detachably mounted to the handpiece. Different electrode assemblies may be selected according to the surgical procedure to be performed. To adapt the generator characteristics for improved electrosurgical performance, each electrode assembly contains an identification element such as a capacitor of unique value which is sensed by the generator. Inside the generator, the sensed capacitor value causes the selection of operating parameters, preferably a nominal generator output power and a peak voltage limit, to suit the selected electrode assembly.

Abstract: In an electrosurgical instrument for the treatment of tissue in the presence of an electrically conductive fluid medium, a bipolar electrode assembly has an active electrode with an exposed tissue treatment portion, a return electrode having an exposed fluid contact surface, and an insulating member positioned between and electrically insulating the active electrode and the return electrode. The insulating member serves to space apart the exposed active electrode treatment portion and the exposed fluid contact portion of the return electrode. The dimensions and configurations of the exposed portions of the electrodes and of the insulating member are such that, when the electrode assembly is immersed in a conductive fluid medium, the ratio between the longest and shortest conduction path lengths between the active and return electrodes is greater than or equal to 1.25 to 1. The invention also includes a combination of an electrosurgical instrument and a radio frequency generator.

Abstract: An electrosurgical instrument, which is used to treat tissue in the presence of an electrically-conductive fluid, comprises an instrument shaft and an electrode assembly at one end of the shaft. The electrode assembly comprises a tissue treatment electrode and a return electrode which is electrically insulated from the tissue treatment electrode by means of an insulation member. The tissue treatment electrode is exposed at the extreme distal end of the instrument, and the return electrode has a fluid contact surface spaced from the exposed end of the tissue treatment electrode by the insulation member. The instrument further comprises feed means for feeding electrically-conductive fluid to the region of the exposed end of 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 and the return electrode.

Abstract: An electrosurgical instrument, which is used for the treatment of tissue in the presence of an electrically-conductive fluid medium, comprises an instrument shaft, and an electrode assembly at one end of the shaft. The electrode assembly comprises a tissue treatment electrode and a return electrode which is electrically insulated from the tissue treatment electrode by means of an insulation member. The tissue treatment electrode is exposed at the distal end portion of the instrument, and the return electrode has a fluid contact surface spaced proximally from the exposed end of the tissue treatment electrode by the insulation member. The exposed end of the tissue treatment electrode is constituted by a plurality of tissue treatment filamentary members made of an electrically-conductive material, the filamentary members being electrically connected to a common electrical supply conductor.

Abstract: An electrosurgical instrument is disclosed for the treatment of tissue in the presence of an electrically-conductive fluid. The instrument comprises an instrument shaft, and a tissue treatment electrode at one end of the shaft, the tissue treatment electrode being constructed to define a plurality of pockets for trapping electrically-conductive fluid. Alternatively, the tissue treatment electrode is made from an electrically-conductive material and is coated with a resistive inert material which is effective to increase the local power density within the tissue treatment electrode.

Abstract: In an electrosurgical instrument for the treatment of tissue in the presence of an electrically conductive fluid medium a bipolar electrode assembly has an active electrode with an exposed tissue treatment portion, a return electrode having an exposed fluid contact surface, and an insulating member positioned between and electrically insulating the active electrode in the return electrode. The insulating member serves to space apart the exposed active electrode treatment portion and the exposed fluid contact portion of the return electrode. The dimensions and configurations of the exposed portions of the electrodes and of the insulating member are such that when the electrode assembly is immersed in a conductive fluid medium, the ratio between the longest and shortest conduction path lengths between the active and return electrodes is less than or equal to 2:1. The invention also includes a combination of an electrosurgical instrument and a radio frequency generator.