A multi-mode electrosurgical apparatus for use in cold plasma applications, electrosurgical cutting, electrosurgical coagulation and mechanical cutting is provided. The electrosurgical apparatus includes a housing having a passage extending therethrough, an electrically conducting tube being disposed in the passage of the housing; an insulating outer tube disposed around the electrically conducting tube coupled to the housing, the electrically conducting tube being movable along a longitudinal axis of the housing and outer tube; an electrically conducting blade coupled to the distal end of the electrically conducting tube, and a transformer assembly disposed on a proximal end of the housing, the transformer assembly including a first transformer and a first switch for selectively coupling the first transformer and an external second transformer to the electrically conducting tube for providing electrosurgical energy thereto.

BACKGROUND

The present disclosure relates generally to electrosurgery and electrosurgical systems and apparatuses, and more particularly, to an electrosurgical apparatus with a retractable blade for use in cold plasma applications, electrosurgical cutting and mechanical cutting.

2. Description of the Related Art

High frequency electrical energy has been widely used in surgery. Tissue is cut and bodily fluids are coagulated using electrosurgical energy.

Electrosurgical instruments generally comprise “monopolar” devices or “bipolar” devices. Monopolar devices comprise an active electrode on the electrosurgical instrument with a return electrode attached to the patient. In monopolar electrosurgery, the electrosurgical energy flows through the active electrode on the instrument through the patient's body to the return electrode. Such monopolar devices are effective in surgical procedures where cutting and coagulation of tissue are required and where stray electrical currents do not pose a substantial risk to the patient.

Bipolar devices comprise an active electrode and a return electrode on the surgical instrument. In a bipolar electrosurgical device, electrosurgical energy flows through the active electrode to the tissue of a patient through a short distance through the tissue to the return electrode. The electrosurgical effects are substantially localized to a small area of tissue that is disposed between the two electrodes on the surgical instrument. Bipolar electrosurgical devices have been found to be useful with surgical procedures where stray electrical currents may pose a hazard to the patient or where other procedural concerns require close proximity of the active and return electrodes. Surgical operations involving bipolar electrosurgery often require methods and procedures that differ substantially from the methods and procedures involving monopolar electrosurgery.

Gas plasma is an ionized gas capable of conducting electrical energy. Plasmas are used in surgical devices to conduct electrosurgical energy to a patient. The plasma conducts the energy by providing a pathway of relatively low electrical resistance. The electrosurgical energy will follow through the plasma to cut, coagulate, desiccate, or fulgurate blood or tissue of the patient. There is no physical contact required between an electrode and the tissue treated.

Electrosurgical systems that do not incorporate a source of regulated gas can ionize the ambient air between the active electrode and the patient. The plasma that is thereby created will conduct the electrosurgical energy to the patient, although the plasma arc will typically appear more spatially dispersed compared with systems that have a regulated flow of ionizable gas.

Atmospheric pressure discharge cold plasma applicators have found use in a variety of applications including surface sterilization, hemostasis, and ablation of tumors. In the latter example, the process can be relatively slow, generate large volumes of noxious smoke with vaporized and charred tissue, and may cause collateral damage to surrounding healthy tissue when high power electrosurgical energy is used. Precision accuracy can also be a problem, due to the width of the plasma beam.

Often, a simple surgical knife is used to excise the tissue in question, followed by the use of a cold plasma applicator for cauterization, sterilization, and hemostasis. An improved approach would have both facilities in the same surgical tool.

SUMMARY

The present disclosure relates to an electrosurgical apparatus with a retractable blade for use in cold plasma applications, electrosurgical cutting, electrosurgical coagulation and mechanical cutting. When the blade is retracted within the electrosurgical apparatus, it is electrically energized while an inert gas flows over it, producing a cold plasma discharge. In the de-energized state, the blade is advanced and used as a traditional surgical blade making contact with tissue to achieve mechanical cutting. Additionally, the blade may be advanced and used while both electrically energized and with inert gas flow. In this mode, the apparatus may be employed for electrosurgical cutting or coagulation.

In one aspect of the present disclosure, an electrosurgical apparatus includes a housing having a passage extending therethrough, the housing having a proximal end and a distal end; an electrically conducting tube having a proximal end and a distal end, the electrically conducting tube being disposed in the passage of the housing; an insulating outer tube having a proximal end and a distal end, the outer tube disposed around the electrically conducting tube with the proximal end of the outer tube coupled to the distal end of the housing, the electrically conducting tube being movable along a longitudinal axis of the housing and outer tube; an electrically conducting blade coupled to the distal end of the electrically conducting tube, and a transformer assembly disposed on the proximal end of the housing, the transformer assembly including a first transformer and a first switch for selectively coupling the first transformer and an external second transformer to the electrically conducting tube for providing electrosurgical energy thereto.

In another aspect, the electrosurgical apparatus further includes a first slider member coupled to the electrically conducting tube for moving the electrically conducting tube thereby extending and retracting the blade about the distal end of the outer tube, the first slider member being accessible on the housing.

In a further aspect, the electrosurgical apparatus includes a second slider member coupled to the switch and configured to operate the switch, the second slider member being accessible on the housing.

In another aspect, the first transformer is a step-up transformer and is configured to receive electrosurgical energy at a first predetermined value and the external second transformer is configured to provide electrosurgical energy to the electrically conducting tube at a second predetermined value.

In yet another aspect, the electrosurgical apparatus includes a plurality of buttons configured to affect at least one electrosurgical mode based on a position of the first switch.

In another aspect, the electrosurgical apparatus includes a second switch configured to determine a position of the blade and generate a signal indicating the position, the signal being transmitted to an electrosurgical generator.

In a further aspect, the proximal end of the electrically conducting tube includes a connector for coupling to a gas source to enable gas to flow through the electrically conducting tube over the blade.

According to another aspect of the present disclosure, an electrosurgical apparatus is provided including an electrosurgical generator coupled to an electrical power supply configured to generate electrosurgical energy, the electrosurgical generator including a step-down transformer coupled to the electrical power source and a first step-up transformer coupled to an output of the step-down transformer; and a handpiece including: a housing having a passage extending therethrough, the housing having a proximal end and a distal end; an electrically conducting tube having a proximal end and a distal end, the electrically conducting tube being disposed in the passage of the housing; an insulating outer tube having a proximal end and a distal end, the outer tube disposed around the electrically conducting tube with the proximal end of the outer tube coupled to the distal end of the housing, the electrically conducting tube being movable along a longitudinal axis of the housing and outer tube; an electrically conducting blade coupled to the distal end of the electrically conducting tube, and a transformer assembly disposed on the proximal end of the housing, the transformer assembly including a second step-up transformer and a first switch for selectively coupling the first step-up transformer and the second step-up transformer to the electrically conducting tube for providing electrosurgical energy thereto.

It should be understood that the drawing(s) is for purposes of illustrating the concepts of the disclosure and is not necessarily the only possible configuration for illustrating the disclosure.

DETAILED DESCRIPTION

Preferred embodiments of the present disclosure will be described hereinbelow with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. In the drawings and in the description which follow, the term “proximal”, as is traditional, will refer to the end of the device, e.g., instrument, apparatus, applicator, handpiece, forceps, etc., which is closer to the user, while the term “distal” will refer to the end which is further from the user. Herein, the phrase “coupled” is defined to mean directly connected to or indirectly connected with through one or more intermediate components. Such intermediate components may include both hardware and software based components.

FIG. 1shows an exemplary monopolar electrosurgical system generally indicated as10comprising an electrosurgical generator (ESU) generally indicated as12to generate power for the electrosurgical apparatus10and a plasma generator generally indicated as14to generate and apply a plasma stream16to a surgical site or target area18on a patient20resting on a conductive plate or support surface22. The electrosurgical generator12includes a transformer generally indicated as24including a primary and secondary coupled to an electrical source (not shown) to provide high frequency electrical energy to the plasma generator14. Typically, the electrosurgical generator12comprises an isolated floating potential not referenced to any potential. Thus, current flows between the active and return electrodes. If the output is not isolated, but referenced to “earth”, current can flow to areas with ground potential. If the contact surface of these areas and the patient is relatively small, an undesirable burning can occur.

The plasma generator14comprises a handpiece or holder26having an electrode28at least partially disposed within a fluid flow housing29and coupled to the transformer24to receive the high frequency electrical energy therefrom to at least partially ionize noble gas fed to the fluid flow housing29of the handpiece or holder26to generate or create the plasma stream16. The high frequency electrical energy is fed from the secondary of the transformer24through an active conductor30to the electrode28(collectively active electrode) in the handpiece26to create the plasma stream16for application to the surgical site18on the patient20. Furthermore, a current limiting capacitor25is provided in series with the electrode28to limit the amount of current being delivery to the patient20.

The return path to the electrosurgical generator12is through the tissue and body fluid of the patient20, the conductor plate or support member22and a return conductor32(collectively return electrode) to the secondary of the transformer24to complete the isolated, floating potential circuit.

In another embodiment, the electrosurgical generator12comprises an isolated non-floating potential not referenced to any potential. The plasma current flow back to the electrosurgical generator12is through the tissue and body fluid and the patient20. From there, the return current circuit is completed through the combined external capacitance to the plasma generator handpiece26, surgeon and through displacement current. The capacitance is determined, among other things, by the physical size of the patient20. Such an electrosurgical apparatus and generator are described in commonly owned U.S. Pat. No. 7,316,682 to Konesky, the contents of which are hereby incorporated by reference in its entirety.

It is to be appreciated that transformer24may be disposed in the plasma generator handpiece26, as will be described in various embodiments below. In this configuration, other transformers may be provided in the generator12for providing a proper voltage and current to the transformer in the handpiece, e.g., a step-down transformer, a step-up transformer or any combination thereof.

Referring toFIG. 2A, an electrosurgical apparatus100in accordance with the present disclosure is illustrated. Generally, the apparatus100includes a housing102having a proximal end103and a distal end105and a tube104having an open distal end106and a proximal end108coupled to the distal end105of the housing102. The housing102includes a right side housing110and left side housing112, and further includes provisions for a button114and slider116. Activation of the slider116will expose a blade118at the open distal end106of the tube104. Activation of the button114will apply electrosurgical energy to the blade118and, in certain embodiments, enable gas flow through the flow tube122, as will be described in detail below.

Additionally, a transformer120is provided on the proximal end103of the housing for coupling a source of radio frequency (RF) energy to the apparatus100. By providing the transformer120in the apparatus100(as opposed to locating the transformer in the electrosurgical generator), power for the apparatus100develops from higher voltage and lower current than that required when the transformer is located remotely in the generator, which results in lower thermalization effects. In contrast, a transformer back in the generator produces applicator power at a lower voltage, higher current with greater thermalization effects. Therefore, by providing the transformer120in apparatus100, collateral damage to tissue at the operative site is minimized.

A cross section view along line A-A of the apparatus102is shown inFIG. 2B. Disposed within the housing102and tube104is flow tube122which runs along the longitudinal axis of the apparatus100. On a distal end124of the flow tube122, the blade118is retained within the flow tube122. A proximal end126of the flow tube122is coupled to a source of gas via a tube connector128and flexible tubing129. The proximal end126of the flow tube122is also coupled to a source of RF energy via plug130which couples to transformer120. The flow tube122is made of an electrically conducting material, preferably stainless steel, as to conduct the RF energy to the blade118when being employed for plasma applications or electrosurgical cutting as will be described below. The outer tube104is constructed from non-conductive material, e.g., Lestran. The slider116is coupled to the flow tube122via a retaining collar132. A printed circuit board (PCB)134is disposed in the housing102and controls the application of the RF energy from the transformer120via the button114.

It is to be appreciated that the slider116may be freely moveable in a linear direction or may include a mechanism for incremental movements, e.g., a ratchet movement, to prevent an operator of the apparatus100from over extending the blade118. By employing a mechanism for incremental movements of the blade118, the operator will have greater control over the length of the exposed blade118to avoid damage to tissue at the surgical site.

An enlarged view of the distal end106of the outer tube104is also illustrated inFIG. 2B. Here, the blade118is coupled to the flow tube122which is held in place in the outer tube104by at least one seal136. The at least one seal136prevents backflow of gas into tube104and housing102. A cylindrical ceramic insert138is disposed in the distal end of the outer tube104to maintain the blade along the longitudinal axis of the apparatus100and provide structural support during mechanical cutting when the blade is exposed beyond the distal end of the outer tube104.

The operational aspect of the apparatus100will now be described in relation toFIGS. 3A and 3B, whereFIG. 3Ashows an enlarged cross section of the apparatus andFIG. 3Billustrates a front view of the apparatus.

Referring toFIG. 3A, the flow tube122is disposed in the outer tube104with a cylindrical insulator140disposed around the flow tube122. Slider116is coupled to the insulator140and is employed to extend and retract the blade118. At the distal end106of the outer tube104, the annular or ring shaped seal136and cylindrical ceramic insert138are disposed about the flow tube122. As can be seen InFIG. 3B, the generally planar blade118is coupled to an inner circumference of the cylindrical flow tube122such that two gas passageways142,144are formed on both sides of the blade118. As gas flows from the proximal end103of the housing through the flow tube122, the gas will pass over the blade118out the distal end106of the outer tube104.

When the blade is in the retracted position as shown inFIG. 3A, the apparatus100is suitable for generating plasma. In the retracted position, RF energy is conducted to a tip146of the blade118from an electrosurgical generator (not shown) via the flow tube122. An inert gas, such as helium or argon, is then supplied to the flow tube from either the electrosurgical generator or an external gas source. As the inert gas flows over the sharp point146of the blade118that is held at a high voltage and high frequency, a cold plasma beam is generated.

Referring toFIG. 4, the blade118is advanced, via slider116, so the tip146is extended pass the distal end106of the outer tube104. In this state, the blade118can be used for two cutting modes: mechanical cutting and electrosurgical cutting. In the mechanical cutting mode, RF or electrosurgical energy is not applied to the flow tube122or blade118, and therefore, the blade118is in a de-energized state. In this mode, the blade118can be used to excise tissue via mechanical cutting. After the tissue is removed, the blade118may be retracted via the slider116and electrosurgical energy and gas may be applied via button114to generate a cold plasma beam for cauterization, sterilization and/or hemostasis of the operative patient site.

In the electrosurgical cutting mode, the blade118is advanced and used while both electrically energized and with inert gas flow. This configuration resembles an electrosurgical knife approach, where the electrosurgical energy does the cutting. However, with the addition of the inert gas flow, cuts made show virtually no eschar, with very little collateral damage along the side walls of the cut. The cutting speed is considerably faster, with less mechanical cutting resistance as compared to when the knife blade is not electrically energized, i.e., the mechanical cutting mode. Hemostasis is also affected during this process.

In another embodiment, an electrosurgical apparatus200as shown inFIG. 5is configured with a structural current limiting capacitor in the distal end of the apparatus or handpiece to limit the current applied to the operative site of the patient. Generally, a capacitor is formed by two parallel conductive plates with an insulating dielectric material in between them. The capacitance is defined by:
C=K∈0(A/d)  (1)

where C is the capacitance in Farads, K is the dielectric constant (sometimes called “relative permittivity”), ∈0is the permittivity of free space (approximately 8.854×10−12Farad/meter), A is the area of the capacitor plates, and d is their separation distance. Some typical values for dielectric constant are 1.000 for a vacuum (by definition), 1.00054 for air, 3.8 for fused quartz, and 2.1 for polytetrafluoroethylene (“Teflon”). The parallel plates of a capacitor can take the form of concentric conductive tubes with the insulating dielectric between them as shown InFIG. 5, and can also form a structural, as well as electrical element.

Referring to the embodiment shown inFIG. 5, the flow tube of the apparatus200includes a first inner flow tube212coupled to a second, outer flow tube213. The inner flow tube212has a smaller outer diameter than the inner diameter of the outer flow tube213. A cylindrical insulator240is disposed around a distal portion of the inner flow tube212and then inserted into the outer flow tube213. As shown inFIG. 5, the inner flow tube212is inserted into the outer flow tube213approximately a distance equal to the length of the insulator240. The resulting coaxial structure250creates a capacitive coupling for the inner and outer flow tubes212,213, where the total capacitance is approximately equal to the capacitance of the coaxial structure250plus the capacitance of the remaining length of outer flow tube213. The coaxial structure250acts as a current-limiting capacitor limiting the current applied to the operative site of the patient. When the slider116is moved to either extend or retract the blade118, the components of the coaxial structure250, including the inner flow tube212, insulator240and outer flow tube213, move together as a fixed unit. In other aspects, the operation of the embodiment shown inFIG. 5is similar to the embodiments described above.

In a further embodiment, the electrosurgical apparatus of the present disclosure will include a variable structural capacitor350as shown inFIG. 6. The capacitance of a structural capacitor can be varied, assuming a fixed dielectric constant K, by varying the area between the inner and outer conductive tubes. Referring toFIG. 6, inner conductive tube312and outer conductive tube313are configured to slide relative to each other, with a sleeve of dielectric insulator340between them fixed to one of the inner or outer tubes312,313respectively. The degree of overlap of the inner and outer conductive tubes312,313affects the resulting capacitance. In the example shown inFIG. 6A, the insulating dielectric sleeve340is fixed to the inner conductive tube312. The approximately 50% overlap of the outer tube313over insulator340, shown inFIG. 6A, results in a relative capacitance value of “C” and 100% overlap shown inFIG. 6B, in a capacitance of “2C.”

While capacitors will block direct current, and provide protection from galvanic currents in an electrosurgical application, capacitors will pass alternating currents as a result of their capacitive reactance, which is defined by:
XC=1/(2πfC)  (2)

where XCis the capacitive reactance (in units of resistance), C is the capacitance, and f is the frequency. Due to this inverse relationship, as the capacitance increases, the capacitive reactance decreases. For a given applied voltage and fixed frequency, as the capacitance increases, the amount of current limited by this capacitor will also increase as a result of decreased capacitive reactance.

In the example shown inFIG. 6, the capacitance setting inFIG. 6Alimits the current to a lower value than the setting shown inFIG. 6B. In this embodiment, a second slider (not shown) provides the opportunity to adjust this value at the hand piece during a surgical procedure, without being interrupted to make an adjustment at the generator.

It is important to note that when adjusting the current limiting value through varying the relative positions of the inner and outer conductive tubes, that other moveable components, such as the position of the retractable blade, not also be affected. One way to achieve this is with a dual slider configuration450as shown inFIG. 7. One side of the slider, or inner conductive tube412, has the dielectric insulating sleeve440to act as the adjustable current limiting capacitor. The other side simply maintains electrical contact to a second outer conductive tube442which attaches to the retractable blade (not shown), and allows relative movement without disturbing the position of the retractable blade. This is illustrated inFIG. 7, showing a low current limit value on the left (FIG. 7A), and a high current limit value on the right (FIG. 7B). The position of the inner “slider” tube412may be controlled manually by the surgeon via a first slider member, or automatically by electromechanical, pneumatic or similar means. This provides the opportunity to create a feedback loop where the current limit is self-adjusted based on a measured parameter such as absorbed power, tissue temperature, tissue impedance or tissue type. A second slider member may be provided and coupled to the outer tube442to extend and retract the blade, when the blade is coupled to the distal end of the outer tube442.

In a further embodiment, the electrosurgical apparatus of the present disclosure will have an articulating distal end. Referring toFIG. 8, the electrosurgical apparatus500will have similar aspects to the embodiments described above with the distal end506, e.g., approximately 2 inches, being flexible to maneuver the distal end506at the surgical site. An additional control517, e.g., a slider, trigger, or the like, is provided in the proximal housing502to control the bending of the distal end506. As in the above described embodiments, a button514is provided to apply electrosurgical energy to the blade518and, in certain embodiment, enable gas flow through the flow tube. Furthermore, slider516will expose the blade518at the open distal end506upon activation.

In one embodiment, the articulating control517will include two wires, one pulling to articulate and one pulling to straighten the distal end506. The outer tube504will be the similar to the design shown inFIG. 2and will be rigid, preferably made of Ultem™ or similar material, up to the last 2 inches which would be made of a material similar to that of a gastrointestinal (GI) flexible scope. In certain embodiments, inside the outer tube504is constructed of a mesh infused Teflon™ or similar material and a flexible insulating material that would allow the distal end506to bend at least 45° and not collapse the inner tube carrying the gas. The blade518will be made of a flexible metallic material such as Nitinol™ that would be able to bend but would retain it's memory in the straightened position. Alternatively, a straight metal blade518would be provided with the distal 2 inches made of a linked metal such that it would still carry a current but would be bendable and the cutting portion of the blade518would be attached to the distal end of the linked portion.

Referring toFIGS. 9-11, an electrosurgical apparatus600in accordance with another embodiment of the present disclosure is illustrated. Generally, the apparatus600includes a housing602having a proximal end603and a distal end605and a tube604having an open distal end606and a proximal end608coupled to the distal end605of the housing602, thereby forming a handpiece. The housing602includes a plurality of buttons607, e.g., buttons614,615and619, and a first slider616and second slider621. Activation of the first slider616will expose a blade618at the open distal end606of the tube604, as described above. Activation of the second slider621sets the apparatus into different modes, as will be described below. Activation of the individual buttons614,615,619will apply electrosurgical energy to the blade618to affect different electrosurgical modes and, in certain embodiments, enable gas flow through an internal flow tube622, as will be described in detail below. Additionally, a transformer assembly620is provided on the proximal end603of the housing602for coupling a source of radio frequency (RF) energy to the apparatus600via cable660and connector662. The cable660includes a plurality of conductors for providing electrosurgical energy to the apparatus600and for communication signals to and from the apparatus600and an RF source, e.g., an electrosurgical generator623. The connector662includes various pins, e.g., pins681,682,683,684,686,688and690, for coupling the connector662to corresponding port625on the generator623, the details of which will be described below.

As can be seen inFIG. 11, the electrosurgical generator623includes a DC power supply672, an oscillator673, a power amplifier674, a step-down transformer675and a step-up transformer676for supplying power to the apparatus600. The electrosurgical generator623further includes a controller677and memory678.

Referring back toFIG. 10, the transformer assembly620includes transformer T1664, e.g., a step-up transformer, and at least one switch666, which is controlled by the second slider621. The switch666is coupled on one end to the conductive flow tube622and the other end of the switch666is adjustable between an output of transformer664and an output received directly from the generator623via pin683, e.g., signal POWER_RF_MONO/ACTIVE_COMMON. The switch666is controlled by the second slider621located on the external surface of the housing602. The second slider621may include a mechanism to lock the slider621in a particular position. In one embodiment, the second slider621controls the switch666and is interlocked to disable other buttons and/or sends signals to the generator623for selecting a mode. In another embodiment, the switch666may be coupled to the first slider616to select a mode based on the position of the conductive flow tube622and/or blade618.

In a first position, switch666is coupled between terminal2and terminal1wherein an output of the transformer664is coupled to the conductive flow tube622. In a second position, switch666is coupled between terminal3and terminal1wherein an output of the generator623, i.e., an external source, is coupled to the conductive flow tube622.

It is to be appreciated that switch666is to have very low stray capacitance between terminals1and2and terminals1and3to avoid mutual coupling of the transformer664and the lines from the generator. Step-up transformers664and676are both operated from the output of step-down transformer675, so their outputs can be configured as to be in-phase. As a result, the potential difference between switch666contacts2and3can be small, depending on the load placed on either of those transformers. This will minimize potential arc-over between those contacts. Stray capacitance may, in general, be minimized by using a small contact area for contacts2and3of switch666(comparable to the area of the plates of a capacitor) within the limits of their current carrying requirements. Maximizing the distance between contacts2and3of switch666when it is in an open state will also reduce stray capacitance (comparable to the distance between two plates of a capacitor).

Furthermore, the position of the blade618determines the position of switch668. Switch668is coupled to the connector662via a conductor, e.g., SLIDER_POSITION_RECG, which signals the generator as to the position of the blade618via pin690. It is to be appreciated that switch668may be toggled between an open and closed position by being either directly or indirectly coupled to the slider616or the conductive flow tube622.

Activation of the individual buttons614,615,619will apply electrosurgical energy to the blade118to affect different electrosurgical modes depending on the position of the blade618. In the embodiment shown, button614is configured for activating the J-Plasma mode, button615is configured for activating a COAG (or coagulation) mode and button619is configured for activating a CUT mode. Two wires or conductors691,692are used to recognize which of the buttons or switches614,615or619are closed or activated. One of these wires, i.e., wire691coupled to pin683, is also employed for applying RF power to blade618when switch666is coupled between terminal3and terminal1wherein an output of the generator623is coupled to the conductive flow tube622. The other wire, i.e., wire692coupled to pin684, is employed to allow controller677to sense which switch or button614,615or619is activated. For example, when switch614is activated, the controller677senses 0 ohms; when switch615is activated, the controller677senses the parallel combination of resistor R2and capacitor C5at a given frequency; and when switch619is activated, the controller677senses the parallel combination of resistor R1and capacitor C4at a given frequency

When the slider616retracts the blade618inside the opening of the tube604, the J-Plasma mode is selected. In this mode, the J-Plasma button614is enabled while the COAG button615and CUT button619are mechanically and/or electrically disabled. Although not shown, the COAG button615and CUT button619may be mechanically disabled by a switch, relay, etc. In the J-Plasma mode, switch666is coupled between terminal2and terminal1wherein an output of the transformer664is coupled to the conductive flow tube622. Additionally, switch668is closes, which signals the controller677in the generator623as to the position of the blade618and that the handpiece is in J-Plasma mode. Upon activation of button614, a signal is sent to the generator623via pin684, e.g., ACT_JPLASMA/ACT_COAG/ACT_CUT, to initiate plasma generation. Subsequently, the generator supplies power via pin686along line RF1_JPL and via pin688along line RF2_JPL, via the step-down transformer675which provides power to step-up transformer664. Furthermore, in J-Plasma mode, activation of button614initiates the flow of gas through the conductive flow tube622. It is to be appreciated that in one embodiment the generator623coupled to the handpiece600may include an internal gas flow controller which receives the signal. In another embodiment, the gas flow controller is located externally of the generator623but may receive the gas activation signal from the generator. In a further embodiment, the gas flow controller is located externally of the generator623but may receive the gas activation signal from the handpiece itself via hardwired or wireless means.

When the slider616extends the blade618beyond the opening of the tube604, the COAG/CUT mode is selected, also known as the general electrosurgery mode. In this mode, the COAG button615and CUT button619are enabled while the J-Plasma button614is mechanically and/or electrically disabled. Although not shown, the J-Plasma button614may be mechanically disabled by a switch, relay, etc. In the COAG/CUT mode, switch666is coupled between terminal3and terminal1wherein an output of the step-up transformer676in the generator623is coupled to the conductive flow tube622, i.e., the transformer664is bypassed. Upon activation of buttons615or619, a signal is sent to the generator via line ACT_JPLASMA/ACT_COAG/ACT_CUT to initiate supply of electrosurgical energy. Subsequently, the generator supplies power via pin683along line POWER_RF MONO/ACTIVE COMMON, which provides power to the conductive flow tube622.

It is to be appreciated that the two step-up transformers664,676(i.e., transformer664in the handpiece600for the J-Plasma mode and transformer676in the generator623for the general electrosurgery mode) have two different power curves. That is their output impedances are matched for different loading conditions. The J-Plasma transformer664in the handpiece600will put out higher voltages than the electrosurgery transformer676in the generator623, but the J-Plasma transformer664is also matched for a higher output impedance for the combined tissue load and the plasma beam impedances in series. The electrosurgery transformer676back in the generator623has a lower output voltage, but higher current capability and its output impedance is matched to the lower impedance value of an electrosurgical blade618in direct contact with tissue. Exemplary values for the output in J-Plasma mode are 10 kilo ohm output impedance, 4 kV to 6 kV peak-to-peak and 140 mA, where the exemplary values for the output in electrosurgery mode are 150-250 ohm output impedance, 300 V to 6.5 kV peak-to-peak and 1.5 Amps. It is to be appreciated these exemplary values are for illustrative purposes only and in use the values may vary.

In some embodiments, gas may be provided to the handpiece600when in COAG/CUT mode. In one embodiment with the blade618extended, a mode button may be provided on the generator to enable gas to flow, e.g., CUT with gas. In another embodiment, when the blade618is retracted, fulguration or fulguration with gas may be enabled from a button in the generator.

In one embodiment, the connector662includes a one-wire chip670, e.g., a memory, including information associated with the handpiece so the generator may recognize the handpiece. When coupled to a generator via pins681and682, the controller677of generator623reads the information contained on the chip670and may perform or execute instructions based on the handpiece type. In other embodiment, the chip670may have read/write capabilities where the chip670can store how many times the handpiece has been used and provide that information to the generator. In certain embodiments, the controller677of generator623may store the number of uses of the apparatus600in memory678and determine that the handpiece600may no longer be used based on a predetermined use limit. In a further embodiment, the chip670may store application specific information for the handpiece that is to be loaded into the generator, e.g., a specific power profile of the handpiece. In another embodiment, the chip670may store information relating to the gas type to be used with the handpiece, e.g., Argon, Helium, etc. In this embodiment, the generator may provide an indication (or prevent operation) if the gas supplied does not match the type designated for the handpiece.

It is to be appreciated that the various features shown and described are interchangeable, that is, a feature shown in one embodiment may be incorporated into another embodiment.