Electrosurgical system with device-specific operating parameters

Abstract

Electrosurgical system (11, 800) for treating tissue at a target site with at least one type of electrosurgical device, wherein each electrosurgical device (10, 810) comprises a shaft (13, 1000) having a distal end and an active electrode connection (58) located near the distal end, wherein the system (11, 800) comprises a generator (28, 804), the generator (28, 804) comprising: a high-frequency power supply (812, 910) for delivering high-frequency energy to the active electrode connection (58) and a return electrode (55, 56), wherein the power supply (812, 910) has an ablation mode and a coagulation mode, each with corresponding output energy settings; a fluid control device (23, 818) for conveying an electrically conductive fluid (50) to the destination, wherein the electrically conductive fluid (50) provides a current path (60) between the active electrode terminal (58) and the return electrode (55, 56); and a control unit (104, 816, 940) that is operational to identify the device type when the device (10, 810) is operationally connected to the generator (28, 804) and to automatically determine at least one operating parameter specific to the device type, wherein the at least one operating parameter includes a possible flow rate for dispensing the electrically conductive fluid (50), wherein the control unit (104, 816, 940) remains operational to activate the fluid control device (23, 818) for pumping the electrically conductive fluid (50) at the possible flow rate, wherein the control unit (104, 816, 940) is furthermore capable of adjusting the possible flow rate based on the device type, and wherein the control unit (104, 816, 940) remains operational, dynamically adjusting the possible flow rate in a device-specific manner depending on the operation with output energy settings that correspond to either an ablation or a coagulation mode.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to an electrosurgical generator used in conjunction with various types of electrosurgical devices that can be connected to the generator to perform electrosurgical procedures on a patient. More specifically, the present invention relates to an electrosurgical generator that determines one or more operating parameters to perform the electrosurgical procedure based on the specific type of electrosurgical device connected to the generator. GENERAL STATE OF THE ART

[0002] The field of electrosurgery encompasses a number of loosely related surgical techniques that have in common the application of electrical energy to alter the structure or integrity of a patient's tissue. Electrosurgical procedures typically work by applying very high-frequency currents to dissect or ablate tissue structures, and the process can be monopolar or bipolar. Monopolar techniques rely on a separate electrode for the return of RF current, located on the patient's body remote from the surgical site, and where the surgical device defines only a single electrode pole that provides the surgical effect. Bipolar devices comprise two electrodes for applying current between their surfaces. Prior art includes WO 2003 / 047 446 A1.

[0003] Electrosurgical procedures and techniques are particularly advantageous because they generally reduce patient bleeding and trauma associated with cutting procedures. Furthermore, electrosurgical ablation procedures, which may reshape tissue surfaces and volumes, cannot be replicated by other treatment modalities.

[0004] Current electrosurgical techniques used for tissue ablation suffer from an inability to control the depth of necrosis in the treated tissue. Most electrosurgical devices rely on the creation of an electric arc between the treatment electrode and the ablated or cut tissue to cause the desired localized heating. However, such arcs often create very high temperatures, causing a necrosis depth of more than 500 µm, often more than 800 µm, and sometimes up to 1700 µm. The inability to control such a depth of necrosis is a major disadvantage of using electrosurgical techniques for tissue ablation, particularly in arthroscopic, otolaryngological, and spinal procedures.

[0005] Radiofrequency (RF) energy is used in numerous surgical procedures because it provides effective resection and coagulation of tissue and relatively easy access to the target tissues through a portal or cannula. However, a typical phenomenon associated with the use of RF in these procedures is that the currents used to achieve the surgical effect can lead to heating of the electrically conductive fluid used during the procedure to deliver the ablation and / or to irrigate the treatment site. If the temperature of this fluid is allowed to rise above a threshold temperature, the heated fluid could lead to unwanted necrosis or injury to surrounding neuromuscular and / or soft tissue structures.

[0006] One attempt to mitigate these harmful effects includes the use of a suction lumen at the distal tip of the electrosurgical device to continually remove affected fluid from the surgical site, thereby reducing the overall temperature. Typical suction systems utilize a surgical vacuum source that is self-regulating to maintain a preset vacuum pressure. Consequently, the preset pressure is applied to each individual device, regardless of the type of device connected. One problem associated with such systems is that the preset pressure derived from the vacuum source is not optimized for the specific device and can negatively impact the effectiveness of these electrosurgical devices.

[0007] Woloszko's US patent application US 2008 / 0167645 A1 describes a control device that regulates suction at the site. The control device receives real-time data from the target site and adjusts the flow of the suction line based on the data. Although the control device described in Woloszko's publication addresses suction, it does not determine or control several other device-specific operating parameters that may affect clinical efficacy.

[0008] Another attempt to mitigate the harmful effects described above involves limiting power output. Typically, an electrosurgical generator includes a user interface that allows the user to adjust various power settings, namely voltage, current, and energy. However, limiting power output is not always desirable. A certain energy level may be appropriate for one type of device and inappropriate for another. Therefore, a preset energy level without reference to the type of ablation device is not optimal.

[0009] An improved generator (the Quantum™ Generator, manufactured by ArthroCare Corporation, Austin, Texas) addresses the above-described weakness. The Quantum Generator is capable of identifying the type of ablation device and predefined voltage settings. This provides a good approach for a variety of procedures, such as arthroscopic procedures.

[0010] However, it is still desirable to determine and control additional operating parameters. Failure to consider or control certain operating parameters (e.g., the flow of an electrically conductive fluid delivered to the target site) may reduce the efficacy of ablation and treatment or result in undesirable tissue heating. Certain open and semi-open procedures, such as ENT and spinal procedures, require the delivery of a conductive fluid to the surgical field. The conductive fluid is typically provided via a gravity feed or a separate fluid delivery pump. In both cases, the flow of the conductive fluid is manually adjusted and often changes from one user to another and from one procedure to another. This variability can lead to suboptimal ablation and tissue heating.

[0011] Accordingly, improved systems and methods for electrosurgical ablation and tissue cutting are still desired, and in particular, improved systems operable to automatically identify various device-specific operating parameters, such as flow, when the ablation device is connected to the generator, SUMMARY OF THE INVENTION

[0012] An electrosurgical system for treating tissue at a target location comprises at least one type of electrosurgical device and a generator adapted to be connected to the device. The generator includes a radiofrequency power supply for delivering radiofrequency energy to the active electrode terminal and a return electrode, and a fluid control device for delivering an electrically conductive fluid to the target location. The control device is operable to identify the device type when the device is operatively connected to the generator and to automatically determine an operating parameter specific to the device type. The operating parameter includes a possible flow rate for delivering the electrically conductive fluid.

[0013] In one embodiment, the controller identifies the device type based on an electrical resistance associated with the device when the device is connected to the generator,

[0014] The device-specific operating parameters of the present invention can vary widely. In one embodiment, the device-specific operating parameter is flow. The controller is configured to determine at least three different possible flow rates for delivering an electrically conductive fluid to the target location based on the device type. A maximum, a minimum, and an initial flow rate can be determined. In another embodiment, the minimum possible flow rate is 45 milliliters per minute and the maximum possible flow rate is 65 milliliters per minute.

[0015] In another embodiment, the controller includes a library of preselected possible operating parameters, and in a preferred embodiment, a library of preselected possible flow rates corresponding to a plurality of device types.

[0016] In another embodiment, the operating parameter includes one or more of the following: alarm condition, power cutoff condition, counter or beep duration, and device activation duration. The alarm condition causes an alarm signal when the alarm condition is reached. The power cutoff condition causes a shutdown or suspension of power output based on at least one of the following: a) device output current, and b) total time the device is connected to the generator.

[0017] In another embodiment, the operating parameter includes a periodic counter (or beep) duration based on the device type, and the controller beeps after each periodic counter duration has elapsed. This provides the user with an idea of ​​the elapsed time.

[0018] In another embodiment, the operating parameter includes a device activation duration based on the device type, and the controller shuts off the delivery of radiofrequency energy to the device after the procedure duration has ended. In one embodiment, the device activation duration is equal to or greater than 20 seconds and less than or equal to 40 seconds. This is useful for certain procedures.

[0019] In another embodiment, the controller is operable to pulse the delivery of radiofrequency energy based on the device type. In another embodiment, the fluid control device is a peristaltic pump.

[0020] In another embodiment, the system includes a first type of electrosurgical device having an integrated fluid delivery channel or conduit for delivering an electrically conductive fluid to the target site.

[0021] In another embodiment, the system includes a reservoir for an electrically conductive fluid in fluid communication with the fluid delivery channel. The system's pump is operable to deliver fluid through the channel to the site. The pump is controlled by the generator and set to a flow rate based on the specific type of device used in the procedure. In another embodiment, the potential flow rate is also based on the power supplied to the device.

[0022] In another embodiment, an electrosurgical method for ablating soft tissue at a target location using at least one type of electrosurgical device comprises the steps of: connecting a first type of electrosurgical device to an electrosurgical generator; automatically determining at least one operating parameter based on identifying the electrosurgical device as a first type of electrosurgical device; activating the fluid control device to transport the electrically conductive fluid at a determined flow rate to the target location; and delivering radiofrequency energy to an active electrode terminal located at the distal end of the electrosurgical device.

[0023] The step of automatically determining may comprise determining an operating parameter selected from the group consisting of flow, alarm conditions, shutdown conditions, counter duration, and device activation duration.

[0024] In another embodiment, the automatically determining step comprises determining at least three possible flow rates based on the device type. The activation step can be performed by an operator by selecting one of the possible flow rates. In another embodiment, the flow rate is also based on an amount of energy delivered to the device.

[0025] In another embodiment, the method further comprises disconnecting the first type of electrosurgical device from the generator and connecting a second type of electrosurgical device to the generator and automatically determining at least one operating parameter based on identifying the electrosurgical device as a second type of electrosurgical device.

[0026] In another embodiment, the first device is suitable for otolaryngological procedures, and the second type of device is configured for ablation of soft tissue in the spine.

[0027] In another embodiment, the method further comprises pulsing the radio frequency energy based on the identification of the device type.

[0028] In another embodiment, the method further comprises pumping the fluid to the target location using a peristaltic pump.

[0029] The description, objects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] They show: Fig. 1A is a perspective view of an electrosurgical system including an electrosurgical device and an electrosurgical generator. Fig. 1B is a front view of the electrosurgical generator of Fig. 1A, which comprises a fluid conveying device, Fig. 1C a partial view of the electrosurgical generator from Fig. 1B with a fluid transport line installed in the fluid conveying device. Fig. 2A a side view of an electrosurgical probe. Fig. 2B an end view of the electrosurgical probe from Fig. 2A. Fig. 3 an electrosurgical probe in which the distal section of the shaft has an angle. Fig. 4 an electrosurgical probe and a separate fluid delivery instrument. Fig. 5 the model of a probe comprising an active electrode with a ring-shaped geometry. Fig. 6A to 6C show the model of a probe having an umbrella-like active electrode. Fig. 7 is a schematic view of an electrosurgical system including a generator, a probe, and a fluid source. Fig. 8 a block diagram of an electrosurgical generator. Fig. 9 is a flowchart of the steps of an electrosurgical method of operation according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Before describing the present invention in detail, it should be understood that this invention is not limited to the particular variations set forth herein, as various changes or modifications may be made to the described invention, and equivalents may be employed, without departing from the spirit and scope of the invention. As will be apparent to those skilled in the art after reading the present disclosure, each of the individual embodiments described and illustrated herein includes discrete components and features that can be readily separated from or combined with the features of any of the several other embodiments without departing from the scope or spirit of the present invention.Furthermore, numerous modifications may be made to adapt a particular situation, material, composition of matter, process, process operation(s), or process step(s) to the objective(s), spirit, or scope of the present invention. All such modifications are intended to be within the scope of the claims as set forth herein.

[0032] The methods mentioned herein may be performed in any logically possible order of the mentioned events, as well as in the mentioned order of events. Furthermore, it is understood that if a range of values ​​is provided, any occurring value between the upper and lower limits of that range and any other specified or occurring value within that specified range is included in the invention. It is also contemplated that all optional features of the described inventive variants may be set forth and claimed independently or in combination with one or more of the features described herein.

[0033] All existing content (e.g., publications, patents, patent applications, and hardware) mentioned herein is hereby incorporated by reference in its entirety, except to the extent that the content conflicts with the present invention (in which case, the present invention prevails). The referenced items are provided solely for their disclosure prior to the filing date of this application. Nothing herein should be construed as an admission that the present invention is not entitled to anticipate such content by virtue of a prior invention.

[0034] A reference to a single element includes the possibility that multiple of the same elements may be present. In particular, the singular forms "a," "an," "an," and "the," as used herein and in the appended claims, include plural references unless the context clearly dictates otherwise. It should also be noted that the claims may be drafted so as not to include any optional elements. Thus, this disclosure is intended to serve as a primary basis for using such exclusive terms as "sole," "only," and the like in connection with the reciting of claim elements or for employing a "negative" limitation.It is also to be understood that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs.

[0035] The treatment device of the present invention may have various configurations. However, one variant of the device utilizes a treatment device that utilizes Coblation® technology.

[0036] The assignee of the present invention has developed Coblation® technology. Coblation® technology involves the application of a radiofrequency voltage differential between one or more active electrodes and one or more return electrodes to develop high electric field intensities near the target tissue. The high electric field intensities can be generated by applying a radiofrequency voltage sufficient to evaporate an electrically conductive fluid across at least a portion of the active electrode(s) in the region between the tip of the active electrode(s) and the target tissue. The electrically conductive fluid can be a liquid or gas, such as isotonic saline, blood, an extracellular or intracellular fluid delivered to or already present at the target site, or a viscous fluid, such as a gel, applied to the target site.

[0037] When the conductive fluid is heated enough so that the atoms evaporate from the surface faster than they condense, a gas forms. When the gas is heated enough so that the atoms collide, releasing electrons in the process, an ionized gas, or plasma (the so-called "fourth state of matter"), forms. In general terms, plasmas can be formed by heating a gas and ionizing the gas by passing an electric current through it or by beaming radio waves into the gas. These methods of plasma formation provide energy to release electrons directly into the plasma. Electron / atom collisions then release more electrons, and the process continues in a cascading manner until the desired level of ionization is reached. A more in-depth description of plasma can be found in the paper "Plasma Physics," by RJ Goldston and PHRutherford of Plasma Physics Laboratory of Princeton University (1995), the entire disclosure of which is hereby incorporated by reference.

[0038] As the density of the plasma or vapor layer becomes low enough (i.e., less than approximately 1020 atoms / cm 3for aqueous solutions), the mean free path of the electrons increases to allow subsequently injected electrons to cause impact ionization within the vapor layer. Once the ion particles in the plasma layer have sufficient energy, they are accelerated towards the target tissue. The energy released by the energetic electrons (e.g., 3.5 eV to 5 eV) can then bombard a molecule and break its bonds, breaking it into free radicals that then combine to form final gaseous or liquid species. Often, the electrons carry the electric current or absorb the radio waves and are therefore hotter than the ions.Thus, the electrons transported away from the tissue toward the return electrode carry most of the plasma heat, allowing the ions to break down the tissue molecules in an essentially non-thermal manner.

[0039] Through this molecular dissolution (rather than thermal evaporation or carbonization), the target tissue structure is removed volumetrically by molecular breakdown of larger organic molecules into smaller molecules and / or atoms, such as hydrogen, oxygen, carbon oxides, hydrocarbons, and nitrogen compounds. This molecular dissolution completely removes the tissue structure, as opposed to dehydrating the tissue material by removing fluid within the tissue cells and extracellular fluids, as typically occurs with electrosurgical desiccation and evaporation. A more detailed description of these phenomena can be found in commonly assigned U.S. Patent No. 5,697,882 C1, the entire disclosure of which is hereby incorporated by reference.

[0040] In some applications of Coblation® technology, radiofrequency (RF) electrical energy is applied in an electrically conductive medium to shrink or remove (i.e., excise, cut, or ablate) a tissue structure and seal the transected vessels in the area of ​​the target tissue. Coblation® technology is also useful for sealing larger arterial vessels, e.g., those with a diameter of approximately 1 mm.In such applications, a radiofrequency energy supply is provided having an ablation mode in which a first voltage is applied to an active electrode sufficient to cause molecular dissolution or disintegration of the tissue, and a coagulation mode in which a second, lower voltage is applied to an active electrode (either the same or a different electrode) sufficient to heat, shrink, and / or achieve hemostasis of severed vessels within the tissue.

[0041] The amount of energy generated by the Coblation® device can be altered by adjusting various factors, such as: the number of active electrodes; the size and spacing of the electrodes; the electrode surface; irregularities and sharp edges on the electrode surfaces; electrode materials; applied voltage and energy; current-limiting devices, such as coils; the electrical conductivity of the fluid in contact with the electrodes; the density of the fluid; and other factors. Accordingly, these factors can be manipulated to control the energy level of the excited electrons. Since different tissue structures have different molecular bonds, the Coblation® device can be configured to produce energy sufficient to break the molecular bonds of a particular tissue, but insufficient to break the molecular bonds of another tissue. Adipose tissue (e.g., depot fat), for example, hasDouble bonds have energy levels substantially higher than 4 eV to 5 eV (typically approximately 8 eV) to break. Accordingly, Coblation® technology does not generally ablate or remove such fatty tissue; however, it can be used to effectively ablate cells to release the internal fat content in liquid form. The factors can, of course, be changed so that these double bonds can also be broken in a similar way to single bonds (e.g., by increasing the voltage or by changing the electrode configuration to increase the current density at the electrode tips). A further description of these phenomena can be found in commonly assigned U.S. Patent Nos. 6,355,032; 6,149,120; and 6,296,136, the entire disclosures of which are hereby incorporated by reference.

[0042] The active electrode(s) of a Coblation® device can be carried in or by an inorganic insulating support positioned near the distal end of the instrument shaft. The return electrode can be located on the instrument shaft, on another instrument, or external to the patient (i.e., as a dispersion pad). The proximal end of the instrument(s) includes the appropriate electrical connectors to couple the return electrode(s) and the active electrode(s) to a high-frequency power supply, such as an electrosurgical generator.

[0043] In one example of a Coblation® device for use with the embodiments disclosed herein, the return electrode of the device is typically spaced proximal to the active electrode(s) by a suitable distance to avoid electrical shorting between the active and return electrodes in the presence of an electrically conductive fluid. In many cases, the distal edge of the exposed surface of the return electrode is spaced approximately 0.5 mm to 25 mm from the proximal edge of the exposed surface of the active electrode(s), preferably approximately 1.0 mm to 5.0 mm. Of course, this distance may vary with different voltage ranges, conductive fluids, and depending on the proximity of tissue structures to the active and return electrodes. The return electrode typically has an exposed length in the range of approximately 1 mm to 20 mm.

[0044] A Coblation® treatment device for use in accordance with the present embodiments may utilize a single active electrode or an array of active electrodes disposed around the distal surface of a catheter or probe. In the latter embodiment, the electrode array typically comprises a plurality of independently current-limited and / or energy-controlled active electrodes for selectively applying electrical energy to the target tissue while limiting the undesirable application of electrical energy to the surrounding tissue and environment resulting from energy loss into surrounding electrically conductive fluids, such as blood, normal saline, and the like. The active electrodes may be independently current-limited by isolating the terminals from one another and connecting each terminal to a separate power source isolated from the other active electrodes.Alternatively, the active electrodes can be connected together at either the proximal or distal ends of the catheter to form a single wire coupled to a power source.

[0045] In one configuration, each individual active electrode in the electrode group is electrically isolated from all other active electrodes in the group within the instrument and is connected to a power source that is isolated from each of the other active electrodes in the group, or to circuits that limit or interrupt current flow to the active electrode when low-resistivity material (e.g., blood, an electrically conductive saline irrigant, or an electrically conductive gel) creates a lower-impedance path between the return electrode and the individual active electrode. The isolated power sources for each individual active electrode may be separate power supply circuits that have internal impedance characteristics that limit power to the associated active electrode when a low-resistance return path is encountered.By way of example, the isolated energy source may be a user-selectable constant current source. In this embodiment, lower impedance paths automatically result in heating levels of lower resistivity, since heating is proportional to the square of the operating current times the impedance. Alternatively, a single energy source may be connected to each of the active electrodes through independently operable switches or through independent current-limiting elements, such as coils, capacitors, resistors, and / or combinations thereof. The current-limiting elements may be provided in the instrument, the connectors, the cable, the control unit, or on the conductive path from the control unit to the distal tip of the instrument. Alternatively, the resistance and / or capacitance on the surface of the active electrode(s) may be increased due to oxide layers forming selected active electrodes (e.g.,a titanium or resistance coating on the metal surface, such as platinum).

[0046] The Coblation® device is not limited to electrically isolated active electrodes or even a multitude of active electrodes. For example, the group of active electrodes can be connected to a single lead extending through the catheter shaft to a radiofrequency energy source.

[0047] The voltage difference applied between the return electrode(s) and the active electrode(s) is at a high or radio frequency, typically between about 5 kHz and 20 MHz, usually between about 30 kHz and 2.5 MHz, preferably between about 50 kHz and 500 kHz, often less than 350 kHz, and often between about 100 kHz and 200 kHz. In certain applications, the Applicant has found that a frequency of about 100 kHz is useful because tissue impedance is much greater at this frequency. In other applications, such as procedures in or on the heart or head and neck, higher frequencies may be desirable (e.g., 400 to 600 kHz) to minimize low-frequency current flow into the heart or the nerves of the head and neck.

[0048] The applied RMS (effective) voltage is typically in the range of approximately 5 volts to 1000 volts, preferably in the range of approximately 10 volts to 500 volts, often between approximately 150 volts to 400 volts, depending on the size of the active electrode, operating frequency, and operating mode of the procedure in question or the desired effect on the tissue (i.e., contraction, coagulation, cutting, or ablation).

[0049] Typically, the peak-to-peak voltage for ablation or cutting with a square waveform is in the range of 10 volts to 2000 volts, and preferably in the range of 100 volts to 1800 volts, and more preferably in the range of approximately 300 volts to 1500 volts, often in the range of approximately 300 volts to 800 volts peak-to-peak (again, depending on the electrode size, number of electrons, operating frequency, and operating mode). Lower peak-to-peak voltages are used for tissue coagulation, thermal tissue heating, or collagen contraction and are typically in the range of 50 to 1500, preferably 100 to 1000, and more preferably 120 to 400 volts peak-to-peak (again, these values ​​are calculated using a square waveform). Higher peak-to-peak voltages, e.g.of more than approximately 800 volts peak to peak may be desirable for ablating harder substances, such as bone, depending on other factors such as the electrode geometries and the composition of the conductive fluid.

[0050] As discussed above, the voltage is typically applied as a series of voltage pulses or in an alternating current with time-varying voltage amplitude at a sufficiently high frequency (e.g., from approximately 5 kHz to 20 MHz) so that the voltage is effectively applied continuously (e.g., compared to lasers targeting shallow necrosis depths, which are generally pulsed at approximately 10 Hz to 20 Hz). Furthermore, the duty cycle (i.e., the cumulative time in any one-second interval during which energy is applied) is approximately 50% for the present invention, compared to pulsed lasers, which typically have a duty cycle of approximately 0.0001%.

[0051] The preferred energy source can deliver a radiofrequency current that is selectable to produce average energy levels ranging from several milliwatts to several dozen watts per electrode, depending on the volume of target tissue being treated and / or the maximum permissible temperature selected for the instrument tip. The energy source allows the user to select the voltage level based on the specific requirements of a particular neurosurgical procedure, cardiac surgery, arthroscopic surgery, dermatological surgery, ophthalmic surgery, open surgery, or other endoscopic surgical procedures. For cardiac procedures and possibly neurosurgery, the energy source can have an additional filter to filter leakage voltages at frequencies below 100 kHz, particularly frequencies around 60 kHz.Alternatively, a power source having a higher operating frequency, e.g., 300 kHz to 600 kHz, may be used in certain procedures where low-frequency stray currents may be problematic. A description of a suitable power source can be found in commonly assigned U.S. Patent Nos. 6,142,992 A and 6,235,020 B1, the entire disclosures of which are incorporated herein by reference.

[0052] The energy source may be current-limited or otherwise controlled so that no undesirable heating of the target tissue or surrounding (non-target) tissue occurs. In a presently preferred embodiment of the present invention, current-limiting coils are connected in series with each independent active electrode, with the coil inductance ranging from 10 µH to 50,000 µH, depending on the electrical properties of the target tissue, the desired tissue heating rate, and the operating frequency. Alternatively, capacitor / coil (LC) circuit structures may be used, as previously described in U.S. Patent No. 5,697,909, the entire disclosure of which is hereby incorporated by reference. Additionally, current-limiting resistors may be selected.Preferably, these resistors have a large positive temperature coefficient of resistance, so that when the current level begins to rise for any individual active electrode in contact with a low-resistance medium (e.g., a saline irrigant or blood), the resistance of the current-limiting resistor increases significantly, thereby minimizing the energy transfer from the active electrode into the low-resistance medium (e.g., a saline irrigant or blood). Furthermore, other treatment methods can be used in the method of the invention, either instead of or in addition to Coblation® technology.

[0053] Fig. 1A shows an electrosurgical system including an electrosurgical generator 28 and an electrosurgical device, such as an electrosurgical probe 10, adapted to apply energy to a target tissue. The electrosurgical probe 10 includes an elongated shaft 13, which may be flexible or rigid, with flexible shafts optionally including support cannulas or other structures (not shown). As discussed below, the present invention may include various electrode configurations that may be used with the electrosurgical probe 10 (e.g., a single electrode, such as a shield electrode, or multiple electrodes).

[0054] The probe 10 is shown with an integrated cable 34. The cable 34 includes a connector 26 to operatively couple the probe 10 and the generator 28. Although the Fig. While the probe 10 shown in Figure 1A includes an integrated cable, the cable need not be integrated with the probe. For example, the probe handle may be configured to receive a cable connector such that the cable is detachable from the probe handle 22.

[0055] The Fig. The electrosurgical system shown in Figure 1A also includes a fluid source 21 containing an electrically conductive liquid 50. The fluid source may be an infusion bag filled with a physiological saline solution. The electrically conductive liquid passes along a flow path from the fluid source 21 to the probe 13 via a fluid transport line 15. A fluid delivery mechanism 23 is disposed in the generator 28 and delivers the liquid along the flow path to the target location. The fluid delivery mechanism may be a pump, such as a peristaltic pump. In one embodiment, and with reference to Fig. 1B to 1C, the fluid transport line 15 is installed in the generator 28 behind a lockable door 16. The fluid transport line 15 is removably positioned or installed along a rail or recess of the pump 23. The flow of the fluid is controlled by the pump, which is controlled by the generator 28.

[0056] The electrosurgical system 11 is also shown including a suction lumen 102 in fluid communication with the electrosurgical probe 10. The suction lumen is connected to a suction pump (not shown). The suction pump may comprise any suitable fluid transport device, such as a vacuum pump and a canister assembly, such as might be provided via a wall outlet in an operating room.

[0057] A foot pedal 37 is shown connected to the power supply 28 via a cable 36. The foot pedal 37 includes a first pedal 39 and a second pedal 41 for remotely adjusting the energy level applied to the electrodes or for selecting an alternative operating mode. Pressing the pedal 39 and the pedal 41 may, for example, correspond to activating the rod electrodes in an ablation or coagulation mode.

[0058] With reference to Fig. 1B, a generator 28 is shown having one or more buttons or selection means (30a, 30b) for changing the applied voltage levels corresponding to the ablation modes and the coagulation modes, respectively. The generator 28 additionally includes a fluid control means 13 for controlling the fluid delivery mechanism 23. One or more displays and indicators (7, 8, 15) are provided to indicate the energy and fluid delivery levels.

[0059] As discussed below, the generator is operable to automatically determine various device-specific operating parameters to perform a procedure. A "device-specific operating parameter" is defined as any operating variable, value, setting, or limitation specific to the electrosurgical device type, excluding predefined settings (namely, the predefined voltage levels for RF energy delivery to the electrode elements of the electrosurgical device).

[0060] In one application, the generator 28 is connected to the electrosurgical device 13. The generator automatically identifies the device type and determines at least one device-specific operating parameter corresponding to the specific device type. An operating mode for the generator related to the operating parameter (e.g., a device-specific optimal flow rate at which to operate the pump) is automatically and dynamically adjusted, not only according to the identified device type, but may also be adjusted according to the expected procedure type and / or a type of target tissue to be treated, which is typically associated with the particular selected device. The operating parameter status can then be presented to the operator, and the operator can then accept or change the device-specific operating parameter and perform the surgical procedure.

[0061] Fig. 2 to 6 depict various electrosurgical devices or wand configurations. Each wand configuration may be suitable for one type of procedure or another. However, it should be understood that the type of electrosurgical device that may be used with or incorporated into the present invention may vary widely. Examples of wands are presented herein, and the invention is not intended to be limited to such embodiments except as specifically limited in the appended claims. With reference to an electrosurgical device 10 in Fig. 2A and Fig. 2B, the electrically insulated electrode terminals 58 are spaced across the surface 82 of an electrode group. The surface 82 of the electrode group and the individual electrode terminals 58 typically have dimensions within the ranges set forth herein. The surface 82 of the electrode group has a circular cross-sectional shape with a diameter D ( Fig. 2B) in the range of 0.3 mm to 10 mm. The surface 82 of the electrode group can also have an oval shape. The individual electrode terminals 58 protrude from the surface 82 of the electrode group by a distance (H) of 0 mm to 2 mm, preferably 0 mm to 1 mm (see Fig. 2A).

[0062] It should be noted that the electrode terminals may be flush with the surface 82 of the electrode array, or the terminals may be recessed into the surface. For example, during dermatological procedures, the electrode terminals 58 may be recessed by a distance of 0.01 mm to 1 mm, preferably 0.01 mm to 0.2 mm. The electrode terminals may also be axially adjustable relative to the surface 82 of the electrode array, allowing the surgeon to adjust the distance between the surface and the electrode terminals.

[0063] The electrode terminals 58 are preferably made of a refractory, electrically conductive metal or alloy, such as platinum, titanium, tantalum, tungsten, and the like. As shown in Fig. As shown in Figure 2B, the electrode terminals 58 are anchored in a support matrix 48 of a suitable insulating material (e.g., a ceramic or glass material such as alumina, zirconia, and the like), which can be formed at the time of manufacture into a flat, hemispherical, or other shape according to the requirements of a particular procedure. A preferred support matrix material is alumina, available from Kyocera Industrial Ceramics Corporation, Elkgrove, Illinois, due to its high thermal conductivity, good electrical insulating properties, high flexural modulus, resistance to carbon tracking, biocompatibility, and high melting point.

[0064] As in Fig. 2A, the support matrix 48 is adhesively bonded to a tubular support member 78 that extends most or all of the distance between the matrix 48 and the proximal end of the probe 10. The tubular member 78 preferably comprises an electrically insulating material, such as an epoxy, an injection-moldable plastic, or a silicone-based material. In a preferred construction technique, the electrode terminals 58 extend through preformed openings in the support matrix 48 so that they protrude above the surface 82 of the electrode array by the desired distance H ( Fig. 2A). The electrodes can then be bonded to the distal surface 82 of the support matrix 48, typically using an inorganic sealing material 80. The sealing material 80 is selected to provide effective electrical insulation as well as good adhesion to both the ceramic matrix 48 and the platinum or titanium electrode terminals. The sealing material 80 should additionally have a compatible thermal expansion coefficient and a melting point well below that of platinum or titanium and alumina or zirconia, which is typically glass or glass-ceramic.

[0065] At the Fig. 2A and Fig. 2B, the probe 10 includes a return electrode 56 to complete the current path between the electrode terminals 58 and the power supply 28. The return electrode 56 is preferably an annular member positioned externally around the shaft 13 of the probe 10. The return electrode 56 may fully or partially encompass the tubular support member 78 to form an annular space 54 therebetween for the flow of an electrically conductive fluid 50 therethrough. The space 54 preferably has a width in the range of 0.15 mm to 4 mm. The return electrode 56 extends from the proximal end of the probe 10, where it is suitably connected to the power supply 28 via connectors 19, 20, at a point approximately proximal to the surface 82 of the electrode array, typically about 0.5 to 10 mm, and more preferably about 1 to 10 mm.

[0066] The return electrode 56 is disposed within an electrically insulating sheath 18, typically formed as one or more electrically insulating sleeves or coatings, such as polytetrafluoroethylene, polyimide, and the like. Providing the electrically insulating sheath 18 over the return electrode 56 prevents direct electrical contact between the return electrode 56 and any adjacent body structure or the surgeon. Such direct electrical contact between a body structure (e.g., a tendon) and an exposed common electrode element 56 could result in undesirable heating and necrosis of the structure at the point of contact, causing necrosis.

[0067] The return electrode 56 is preferably formed from an electrically conductive material, usually a metal selected from the group consisting of stainless steel alloys, platinum or its alloys, titanium or its alloys, molybdenum or its alloys, and nickel or its alloys. The return electrode 56 may be formed from the same metal or alloy that forms the electrode terminals 58 to avoid any risk of corrosion or the generation of electrochemical potentials that would be due to the presence of dissimilar metals contained in an electrically conductive fluid 50, such as an isotonic saline solution (discussed in more detail below).

[0068] As in Fig. 2A, the return electrode 56 is not directly connected to the electrode terminals 58. To complete this current path so that the terminals 58 are electrically connected to the return electrode 56 via the target tissue 52, an electrically conductive fluid 50 (e.g., an isotonic saline solution) is caused to flow along fluid paths 83. Fluid path 83 is formed by an annular space 54 between the outer return electrode 56 and the tubular support member 78. An additional fluid transport lumen 57 in an inner tubular member 59 is provided to communicate with a fluid transport device or suction source (such as a suction pump 100) via a suction lumen 102 and to remove tissue and other material from the treatment site.In some embodiments, the fluid transport lumen 57 may optionally be used to deliver a conductive fluid to a treatment site.

[0069] When a voltage difference is applied between an electrode group 12 and a return electrode 56, high electric field intensities are generated at the distal tips of the terminals 58, with current flow from the group 12 through the target tissue to the return electrode, the high electric field intensities causing ablation of tissue 52 in the area 88. The operating parameters of the power supply 28 or probe 10 are preferably monitored by the controller 104 during their operation, and suction is applied via the suction pump 100 at a desired flow and / or pressure to remove the ablated tissue and other material from the treatment site to maintain a stable plasma field and associated vapor layer conditions.

[0070] Fig. Figure 3 depicts another probe 10 in which the distal portion of the shaft 13 is bent such that the electrode terminals extend transversely to the shaft. Preferably, the distal portion of the shaft 13 is perpendicular to the remainder of the shaft so that the electrode surface 82 is generally parallel to the shaft axis, as shown in Fig. 3. In this embodiment, the return electrode 55 is mounted on the outer surface of the shaft 13 and is covered with an electrically insulating sheath 18. The electrically conductive fluid 50 flows along the flow path 83 through the return electrode 55 and exits the distal end of the electrode 55 at a point proximal to the electrode surface 82. The fluid is directed outside the shaft to the electrode surface 82 to create a return current path from the electrode terminals 58 through the target tissue 52 to the return electrode 55, as shown by the current flow lines 60, and then removed via the transport lumen 57.

[0071] Fig. 4 depicts an electrosurgical system 11 further including a separate fluid delivery instrument 64 for delivering an electrically conductive fluid 50 between the electrode terminals 58 and the return electrode 55. The fluid delivery instrument 64 includes an inner tubular member or return electrode 55 surrounded by an electrically insulating sheath 18. The return electrode 55 defines an internal passage 83 for the flow of the fluid 50. As shown in Fig. 4, the distal portion of the instrument 64 is preferably curved so that the fluid 50 is discharged at an angle relative to the instrument 64. This allows the surgical team to position the fluid delivery instrument 64 adjacent the electrode surface 82 with the proximal portion of the delivery instrument 64 oriented at a similar angle to the probe 10. The transport lumen 57 can preferably be used in conjunction with a suction pump and controller to remove ablated tissue from a treatment site at a desired flow rate according to operating parameters indicative of the conditions at the distal portion of the probe 10.

[0072] Fig. Figure 5 depicts another probe 10 comprising a single active electrode 58 having a tubular geometry. As described above, the return electrode may be an outer tubular member 56 and may be adhesively bonded to the active electrode support members 48a and 48b. The electrode support members 48a and 48b may be made of ceramic, glass-ceramic, or other electrically insulating material that resists carbon tracking or arc tracking. A preferred material for an electrode support member is alumina. In the exemplary embodiment, alumina forms an inner portion 48b of the electrode support member 48, and a hollow tube of alumina forms an outer portion 48a of the electrode support member 48. The fluid transport lumen 57 is provided within the inner portion 48b.A tubular or annular active electrode 58 may be fabricated using a shaped cylinder of this metal comprising an electrically conductive metal such as platinum, tantalum, tungsten, molybdenum, niobium, or alloys thereof. An electrically insulating sheath 18 surrounds the tubular member 56 and may be spaced from the member 56 by a plurality of longitudinal ribs 96 to define an annular space 54 therebetween (Fig. Fig. 5). The annular space 54 preferably has a width in the range of 0.15 to 4 mm. The ribs 96 can be formed either on the shell 18 or the tubular member 56. The distal end of the return electrode 56 is preferably located approximately 0.5 mm to 10 mm, and more preferably approximately 1 to 10 mm, from the support surface and is generally dependent upon the electrical conductivity of the rinsing solution.

[0073] The Fig. The configuration shown in Figure 5 can be used with the integrated supply means and the return electrodes described above. Alternatively, this probe configuration can be Fig. 5 can be actuated in body cavities that already contain an electrically conductive fluid, thereby avoiding the need for either an integrated fluid supply or an electrically insulating sleeve to form a conduit for the supply of the electrically conductive fluid 50. Instead, an electrically insulating cover can be applied to substantially the entire return electrode 56 (except for the proximal portion).

[0074] With reference to Fig. 6A through 6C depict an alternative embodiment including an electrode with a metal shield 610. As shown, the metal shield 610 includes a plurality of circumferential openings 612 to receive the electrode terminals 1040 and a plurality of internal openings 614 to allow aspiration of fluid and tissue through the opening 609 of the fluid transport lumen. As shown, the shield 610 is press-fitted over the electrode terminals 1040 and then adhesively bonded to the shaft 1000 of the probe 10. In alternative embodiments, the metal shield 610 may include a grid-like configuration and may further include various conductive metals, such as titanium, tantalum, steel, stainless steel, tungsten, copper, gold, or the like.

[0075] Fig. 7 is a schematic diagram of an electrosurgical system 800 according to an embodiment of the present invention. The electrosurgical system 800 includes a generator 804, an electrosurgical wand 810 coupled to the generator, and a fluid source or supply 850 in fluid communication with the generator 804. As described herein, the generator is operable to automatically identify the type of device 810 when the device is connected to the generator. The generator further determines at least one device-specific operating parameter corresponding to the specific device type. An operating mode for the generator that corresponds to the device-specific operating parameter (e.g.,The operating parameter associated with the device (e.g., a device-specific optimal flow rate at which to activate the pump) is automatically and dynamically adjusted not only according to the identified device type, but may also be according to an expected type of procedure and / or a type of target tissue to be treated, which are typically associated with the particular device selected. The status of the operating parameter can then be presented to the operator, and the operator can then accept or modify the device-specific operating parameter and perform the surgical procedure.

[0076] The generator 804 may include any suitable hardware and software (including, without limitation, microprocessors and programmable logic controllers) necessary to obtain and receive input and to control various outputs, such as activating and controlling the RF power output, a fluid delivery component, or, if applicable, an exhaust source. Fig. The generator shown in Figure 7 includes an RF power output 812, a controller 816, and a fluid delivery component 818. The fluid delivery component 818 may be a pump, such as a peristaltic pump, or another mechanism to control the flow of fluid from the fluid supply 850 to the wand 810. In an alternative embodiment, the fluid delivery component 818 is a controllable valve that restricts flow through the transport line.

[0077] The individual components or modules of the generator can be configured differently. Fig. Figure 8 depicts a block diagram of a configuration for a generator according to the present invention. In particular, the generator 900 design includes a plurality of modules, including an AC / DC circuit 910 for converting a typical 120V AC to 12V DC, and an RF output circuit 920 for providing an RF output to an electrosurgical device. A rod type detection circuit 930 for detecting specific rod types provides an input to a control logic circuit 940. Control logic circuits 940 (or sometimes referred to herein as a "controller") are operable to detect information unique to the type or category of rods. In one embodiment, the rod type is identified based on the electrical resistance of the rod (e.g., each rod type can be designed to have a unique electrical resistance in a rod ID circuit).Although electrical resistance is described as one technique for identifying the rod type, other identification and detection techniques are intended to be part of the present invention unless excluded by the appended claims. Indeed, the specific technique for identifying the rod can vary widely. In addition to automatic detection, the operator can manually select the rod type.

[0078] Fig. Figure 8 also shows a pump circuit 950 for receiving a signal from the control logic circuit and changing the output flow to the pump. Fig. The modules shown in Figure 8 are integrated into a generator. However, in other embodiments, the modules and components may be integrated differently or be independent.

[0079] Fig.Figure 9 illustrates an operating method according to an embodiment of the present invention. First, the control unit is switched on 1010 and initialized 1020.

[0080] The controller then determines whether an electrosurgical device is operably coupled to the generator 1030. If no rod is detected, the controller may indicate this fact or an error.

[0081] If a bar is detected in step 1030, the controller identifies the bar type 1040. Identifying the bar type may be done by comparing the characteristics of the detected bar with a library of characteristics of known bar types. The library or database may be stored in the generator on removable media or may be accessible via an internet or server connection. Alternatively, the bar type may be determined using an algorithm or program.

[0082] The generator is capable of identifying many different rod types. Preferably, the number of matchable rod types comprises more than 2 and fewer than 50, more preferably approximately 2 to 20 rod types, and most preferably between 5 and 10. At least one device-specific operating parameter is associated with each stored rod type. Such a device-specific operating parameter can be provided for each device based on analytical, theoretical, and / or empirical data.

[0083] Once the rod type is identified, the controller sets at least one operating parameter corresponding to the specific rod type 1050. The device-specific operating parameters include, without limitation, a) flow rates at which the electrically conductive fluid is to be conveyed through the transport line, b) alarm conditions, c) power-off conditions, d) counter or timer durations, and e) device activation durations. These device-specific operating parameters are preferably determined automatically and serve to optimize the intervention and minimize human error.

[0084] Flow is a device-specific operating parameter according to the present invention. Preferably, but not necessarily, at least three possible flow rates are set by the controller. Examples include a minimum flow rate, a maximum flow rate, and an initial flow rate. In one embodiment, the flow rate ranges from 5 to 50 ml per minute, and more preferably from 45 to 65 ml per minute for certain ENT rod procedures (e.g., turbinate reduction) and 10 to 16 ml per minute for spinal surgical procedures (e.g., discectomy). In addition, the controller may be operable to further change and optimize the operating flow rates for a specific rod type based on the output energy setting (i.e., voltage settings applicable to ablation or coagulation modes) or based on the voltage level selected by the operator.For example, the controller can be programmed so that detecting a higher voltage level setting would result in a higher (or lower) flow rate in one device type and not another. As another example, the controller can be programmed so that operating at specific output energy settings corresponding to either an ablation or coagulation mode would result in a dynamic flow rate adjustment for specific devices.

[0085] The alarm condition is another device-specific operating parameter. Each rod type can include individual alarm conditions. These may include one or more of the following: a) monitoring the rod's output current and setting the appropriate current-limiting fault trip points, b) monitoring the temperature for various internal components in the RF generator assembly, and c) limiting the total time the rod can be operationally connected to the RF generator.

[0086] The counter or beep duration is another device-specific operating parameter. For wands typically used in a time-based procedure, such as turbinate reduction, where the electrosurgical device is activated for a set period of time to create a lesion, the beep function in the system can be set to a periodic counter duration (e.g., five seconds) so that each time the ablation setting of that wand is activated, the generator produces an audible tone at each counter duration to indicate to the user that the wand has been activated for an elapsed period. The frequency of the beep function in the system can be set to a different time interval for each wand type.

[0087] Device activation duration is another device-specific operating parameter. For rods typically used in a time-based procedure, such as a turbinate reduction procedure as described above or a disc decompression procedure, where the electrosurgical device is activated for a set period of time to limit ablation within the disc space, the timer function in the system can be adjusted to enable the appropriate duration of RF output from the generator. Non-limiting examples include 20 seconds for turbinate reduction procedures, 10 to 20 seconds for various percutaneous discectomy-type procedures, and 40 seconds for open discectomy-type procedures. The device activation duration, during which the RF can remain active in the system, is set to different time intervals for each applicable rod type.

[0088] After the possible operating parameters have been set in step 1050, the operator can enter or change the possible device-specific operating parameters. This user input step 1060 allows the operator to accept, increase, or decrease the operating parameters (e.g., flow rate) within the specified range for the rod type desired by the physician.

[0089] Subsequently, and where applicable, the control unit instructs the pump to prime line 1070. This is necessary to remove air and gas from the line before ablation begins.

[0090] Next, step 1080 illustrates RF activation to ablate or otherwise treat a target tissue using the wand. The procedure can be repeated as desired and performed with numerous wand types.

[0091] The method described above is an illustration of one embodiment. Other changes and variations may be made to the disclosed embodiments without departing from the present invention. For example, although the controller, power supply, and fluid delivery device have been described above as an integrated assembly, they are not necessarily so integrated. The components may be independent devices and may be adapted to communicate with each other via input and output ports. Additionally, other uses and applications are possible. Numerous other methods for controlling or labeling instruments or otherwise treating tissue using electrosurgical probes will be apparent to those skilled in the art. Furthermore, the instruments and methods described herein may be incorporated into instruments for various body areas (e.g.,Mouth, nasal passages and other respiratory tracts, intervertebral discs, spine, shoulder, knee, etc.) and for other tissue treatment procedures (e.g., discectomy, tonsillectomy, turbinate reduction, chondroplasty, menectomy, etc.). Although the embodiments have been described in detail by way of example and for the sake of clarity, various changes, adaptations, and modifications will be apparent to those skilled in the art. Therefore, the scope of the present invention is limited solely by the appended claims.

Claims

[1] An electrosurgical system (11, 800) for treating tissue at a target location using at least one type of electrosurgical device, each electrosurgical device (10, 810) comprising a shaft (13, 1000) having a distal end and an active electrode terminal (58) disposed proximate the distal end, the system (11, 800) comprising a generator (28, 804), the generator (28, 804) comprising: a radio frequency energy supply (812, 910) for delivering radio frequency energy to the active electrode terminal (58) and a return electrode (55, 56), the energy supply (812, 910) having an ablation mode and a coagulation mode, each with corresponding output energy settings; a fluid control device (23, 818) for conveying an electrically conductive fluid (50) to the target location, wherein the electrically conductive fluid (50) provides a current path (60) between the active electrode terminal (58) and the return electrode (55, 56); and a controller (104, 816, 940) operable to identify the device type when the device (10, 810) is operatively connected to the generator (28, 804) and to automatically determine at least one operating parameter specific to the device type, wherein the at least one operating parameter includes a possible flow rate for dispensing the electrically conductive fluid (50), wherein the control device (104, 816, 940) is further operable to activate the fluid control device (23, 818) for conveying the electrically conductive fluid (50) at the possible flow rate, wherein the controller (104, 816, 940) is further operable to adjust the possible flow based on the device type, and wherein the controller (104, 816, 940) is further operable to dynamically adjust the potential flow on a device-specific basis depending on operation with output energy settings corresponding to either an ablation or a coagulation mode. [2] The system (11, 800) of claim 1, wherein the controller (104, 816, 940) determines at least 3 different possible flow rates for delivering an electrically conductive fluid (50) to the target location based on the device type. [3] The system (11, 800) of claim 1, wherein the controller (104, 816, 940) determines a minimum and maximum possible flow rate for delivering an electrically conductive fluid (50) to the target location based on the device type. [4] The system (11, 800) of claim 3, wherein the minimum possible flow rate is 8 milliliters per minute and the maximum possible flow rate is 65 milliliters per minute. [5] The system (11, 800) of claim 1, wherein the controller (104, 816, 940) includes a library of preselected possible flow rates corresponding to a plurality of device types. [6] The system (11, 800) of claim 1, wherein the controller (104, 816, 940) identifies the device type based on an electrical resistance associated with the device (10, 810) when the device (10, 810) is connected to the generator (28, 804). [7] The system (11, 800) of claim 1, wherein the at least one operating parameter further comprises one or more of the following: alarm condition, power off condition, counter duration, and device activation duration. [8] The system (11, 800) of claim 7, wherein the at least one operating parameter comprises the alarm condition and the controller (104, 816, 940) generates an alarm signal when the alarm condition is reached. [9] The system (11, 800) of claim 7, wherein the at least one operating parameter comprises the power off state, and the power off condition comprises at least one of the following: a) output current of the device (10, 810) and b) total time the device (10, 810) is connected to the generator (28, 804). [10] The system (11, 800) of claim 7, wherein the at least one operating parameter comprises a periodic counter duration based on the device type, and wherein the controller (104, 816, 940) indicates the termination of the counter duration. [11] The system (11, 800) of claim 10, wherein the generator (28, 804) includes an audible tone function. [12] The system (11, 800) of claim 7, wherein the at least one operating parameter comprises the device activation duration based on the device type, and the controller (104, 816, 940) turns off the delivery of radio frequency energy to the device (10, 810) after the device activation duration has ended. [13] The system (11, 800) of claim 12, wherein the device activation duration is equal to or longer than 20 seconds and less than or equal to 40 seconds. [14] The system (11, 800) of claim 1, wherein the fluid control device (23, 818) is a peristaltic pump (23). [15] The system (11, 800) of claim 14, further comprising a first type of electrosurgical device, and the first type of device includes an integrated fluid delivery channel (15). [16] The system (11, 800) of claim 15, further comprising a reservoir containing an electrically conductive fluid (50). [17] The system (11, 800) of claim 16, further comprising a foot pedal (37) for activating the delivery of radio frequency energy to the active electrode terminal (58). [18] An electrosurgical generator (28, 804) for treating tissue at a target location using at least one type of electrosurgical device, each electrosurgical device (10, 810) comprising a shaft (13, 1000) having a distal end and an active electrode terminal (58) disposed proximate the distal end, the generator (28, 804) comprising: a radio frequency energy supply (812, 910) for delivering radio frequency energy to the active electrode terminal (58) and a return electrode (55, 56), the energy supply (812, 910) having an ablation mode and a coagulation mode, each with corresponding output energy settings; a fluid control device (23, 818) for controlling an electrically conductive fluid (50) to the target location, wherein the electrically conductive fluid (50) provides a current path (60) between the active electrode terminal (58) and the return electrode (55, 56); and a controller (104, 816, 940) operable to identify the device type when the device (10, 810) is operatively connected to the generator (28, 804) and to automatically determine at least one operating parameter specific to the device type, wherein the at least one operating parameter includes a possible flow rate for dispensing the electrically conductive fluid (50), wherein the control device (104, 816, 940) is further operable to activate the fluid control device (23, 818) for conveying the electrically conductive fluid (50) at the possible flow rate, and wherein the controller (104, 816, 940) is further operable to adjust the possible flow based on the device type, and the control device (104, 816, 940) is further operable to dynamically adjust the possible flow rate on a device-specific basis depending on operation with output energy settings corresponding to either an ablation or a coagulation mode. [19] An electrosurgical generator (28, 804) for treating tissue at a target location using at least one type of electrosurgical device, each electrosurgical device (10, 810) comprising a distal end and an active electrode terminal (58) disposed proximate the distal end, the generator (28, 804) comprising: a radio frequency energy supply (812, 910) for delivering radio frequency energy to the active electrode terminal (58) and at least one return electrode (55, 56) spaced proximally from the active electrode terminal (58), the energy supply (812, 910) having an ablation mode and a coagulation mode, each with corresponding output energy settings; a fluid control device (23, 818) for delivering an electrically conductive fluid (50) to the target location, and wherein the electrically conductive fluid (50) provides a current path (60) between the active electrode terminal (58) and the return electrode (55, 56); and a controller (104, 816, 940) operable to identify the device type when the device (10, 810) is operatively connected to the generator (28, 804) and to automatically determine at least one operating parameter specific to the device type, wherein the controller (104, 816, 940) is further operable to automatically change at least one operating mode of the generator (28, 804) associated with the at least one operating parameter, wherein the at least one operating parameter includes a possible flow rate for dispensing the electrically conductive fluid (50), wherein the control device (104, 816, 940) is further operable to activate the fluid control device (23, 818) for conveying the electrically conductive fluid (50) at the possible flow rate, and wherein the controller (104, 816, 940) is further operable to adjust the possible flow based on the device type, and the control device (104, 816, 940) is further operable to dynamically adjust the possible flow rate on a device-specific basis depending on operation with output energy settings corresponding to either an ablation or a coagulation mode. [20] The generator (28, 804) of claim 19, wherein the at least one operating parameter comprises a plurality of operating parameters. [21] The generator (28, 804) of claim 20, wherein the plurality of operating parameters comprises one or more of the following: alarm condition, power off condition, counter duration, and device activation duration. [22] The generator (28, 804) of claim 19, wherein the at least one operating parameter specific to the device type is further specific to an intervention type. [23] The generator (28, 804) of claim 19, wherein the at least one operating parameter specific to the device type is further specific to a type of target tissue (52). [24] Controller (104, 816, 940) for an electrosurgical device (10, 810), comprising: Sensor means (930) for detecting a characteristic of an electrosurgical device (10, 810) coupled to the controller (104, 816, 940); and a processor (940) operable to control a fluid transport device (23, 818) to modify the flow of fluid (50) in the electrosurgical device (10, 810); wherein the controller (104, 816, 940) is operable with different energy settings, wherein at least one energy setting corresponds to an ablation mode and wherein at least one energy setting corresponds to a coagulation mode; wherein the processor (940) is configured that it operates the controller (104, 816, 940) with one of the power settings, that it regulates the flow of the fluid (50) based on the detected characteristics of the electrosurgical device (10, 810), and that it dynamically regulates the flow in a device-specific manner depending on operation with output energy settings corresponding to either an ablation or a coagulation mode. [25] The controller (104, 816, 940) for an electrosurgical device (10, 810) of claim 24, wherein controlling the flow of the fluid (50) comprises specifying a flow rate limit and controlling the flow of the fluid (50) in the electrosurgical device (10, 810) based on the flow rate limit. [26] The controller (104, 816, 940) for an electrosurgical device (10, 810) of claim 25, wherein the flow rate limit comprises one of a maximum flow rate and a minimum flow rate. [27] A controller (104, 816, 940) for an electrosurgical device (10, 810) according to any one of claims 24 to 26, wherein controlling the flow of the fluid (50) comprises setting an initial flow rate such that when the electrosurgical device (10, 810) is used, the flow of the fluid (50) is controlled to flow at the initial flow rate. [28] A controller (104, 816, 940) for an electrosurgical device (10, 810) according to any one of claims 24 to 27, wherein the characteristic of an electrosurgical device (10, 810) comprises one of an impedance of the electrosurgical device (10, 810) and a data value identifying the device (10, 810). [29] A controller (104, 816, 940) for an electrosurgical device (10, 810) according to any one of claims 24 to 28, wherein the processor (940) is operable to control a power control device (920) to modify the electrical power supplied by the electrosurgical device (10, 810), and the processor (940) is configured to control the electrical power supplied by the electrosurgical device (10, 810) based on the sensed characteristic. [30] The controller (104, 816, 940) for an electrosurgical device (10, 810) of claim 29, wherein controlling the electrical power supplied by the electrosurgical device (10, 810) comprises controlling the duration of continuous supply of electrical power by the electrosurgical device (10, 810) such that after a selected duration of continuous actuation, the controller (104, 816, 940) stops supplying electrical power. [31] A controller (104, 816, 940) for an electrosurgical device (10, 810) according to claim 29 or 30, coupled to sensor means for sensing the electrical current supplied by the electrosurgical device (10, 810), and in which regulating the power supplied by the electrosurgical device (10, 810) comprises interrupting the supply of electrical power in the event that the sensed electrical current exceeds a selected value, the selected value being based on the sensed characteristic. [32] An electrosurgical system (11, 800) comprising the controller (104, 816, 940) for an electrosurgical device (10, 810) according to any one of claims 24 to 31.

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