MXPA00003679A

MXPA00003679A - Electrosurgical system for reducing/removing eschar accumulations on electrosurgical instruments

Info

Publication number: MXPA00003679A
Application number: MXPA/A/2000/003679A
Authority: MX
Inventors: Warren Paul Heim; Scott Allan Miller Iii; James L Brassell
Original assignee: Team Medical Llc
Priority date: 1997-10-15
Filing date: 2000-04-14
Publication date: 2001-12-13

Abstract

An electrosurgical system is disclosed that applies electrical energy to obtain a predetermined surgical effect, while also reducing eschar deposits on a working surface of an electrosurgical instrument (4), producing an eschar deposit which is easily removed from the working surface, and/or facilitating removal of eschar deposits during a cleaning procedure. Such benefits may be realized by providing a negative bias on the working surface relative to a return path (7) to source (1) during electrosurgical procedures, and/or during a cleaning procedure which may include contacting the working surface with an electrically conductive liquid.

Description

ELECTROQIHRÚRGICO SYSTEM TO REDUCE / REMOVE ESCARA ACCUMULATIONS IN INSTRUMENTS ELECTROQUIRÚRGICOS FIELD OF THE INVENTION The present invention relates to methods and assemblies that employ the application of electrical energy to tissue to achieve a predetermined surgical effect, and more particularly, to achieve said effect with reduced accumulation of body materials in the electrosurgical instrument. Additionally, the invention relates to methods and configurations to facilitate the removal of bodily materials that can accumulate in an electrosurgical instrument during surgical procedures. BACKGROUND OF THE INVENTION The potential uses and recognized advantages of employing electric power for surgical purposes are constantly increasing. In particular, for example, electrosurgical techniques are currently being widely used to provide highly localized coagulation and tissue cutting capabilities in open and laparoscopic applications, thus producing reduced tissue trauma and additional advantages compared to previous traditional surgical approaches . Electrosurgical techniques include the use of a portable instrument or pencil that has one or more work surfaces that transfer radio frequency (RF) electrical energy to the tissue (for example, via a stainless steel scalpel or scalpel), a source of energy radio frequency (RF) electrical equipment (for example, a dedicated electrosurgical generator) and a return path device, commonly in the form of a return electrode bearing that can be placed in body contact in or immediately adjacent to the surgical site. The return path device provides an electrical path of return of the patient's tissue to the energy source. More particularly, the instrument and the return path device are interconnected via wire (s) electrically conductive to the source of the radio frequency electric power which serves as the source and the dissipator so that the electrical energy produces an electrical circuit full. When a portable instrument and a return path bearing are used, the electrosurgical technique is called monopolar. When a portable instrument and a smaller return path electrode are used (ie, which can be placed in or immediately adjacent to the surgical site) the electro-surgical technique is called bipolar. The waveforms produced by the radio frequency electric source can be designed to produce a predetermined electrosurgical effect, namely, coagulation or tissue cutting. In this respect, prior to the present invention, the coagulation / tissue cutting effects have been the only parameters considered in the design of electrochemical waveforms.

Despite the disadvantages associated with known electrosurgical techniques, a concomitant implication has been that deposits accumulate on the work surfaces of the surgical instrument that pass electrical energy to the tissue. The deposits are formed of material that comes out of the fabric and makes contact with the work surfaces, and of fabric material that directly contacts the work surfaces and adheres to them. Commonly, work surfaces heat up as electrical power is applied to them, which in turn causes the deposited materials to change their physical and chemical composition. The deposits are commonly called eschar. As the eschar accumulates and becomes thicker, it negatively and progressively affects the corresponding electrosurgical procedure (for example, cutting). That is, for example, the scara, accumulates to such a thickness that a surgeon must interrupt the surgical procedure to clean the work surfaces of the instrument. Cleaning commonly includes the use of abrasive bearings that scrape the encrusted eschar from the surfaces of P instrument work. As the surgical procedure continues, the described cleaning procedure should be performed more frequently. These cleaning stops interfere with the effectiveness of the surgical procedure, cause delays and cause significant discomfort for physicians. In addition to the use of abrasive bearings, other approaches to treating the deposits of eschar have been limited to treating the electrosurgical blades with or making the blades of materials intended to reduce the accumulation of eschar. Such methods have included the electropolishing of stainless steel electrosurgical blades. Other methods have included covering work surfaces with fluorinated hydrocarbon materials (see, for example, Patent of the United States of America Serial number 4,785,807) and coating niobium blades with a niobium oxide (see, e.g., U.S. Pat.

Serial Number 5,030,218). These approaches to eschar reduction still produce deposits of eschar and require a focused effort on the part of physicians to remove the deposit of eschar from the working surfaces of the surgical instrument.

Additionally, such cleaning often removes or otherwise degrades the special surface treatments of the work surfaces, which reduces its effectiveness as the surgical procedure proceeds. BRIEF DESCRIPTION OF THE INVENTION Accordingly, a primary objective of the present invention is to provide an improved electrosurgical system for employing electrical energy to achieve a desired electrosurgical effect while reducing the amount of eschar deposited in the surgical instrument and the degree of adherence of said instrument. it's expensive. Another object of the present invention is to provide a method and apparatus for removing accumulated eschar in a surgical instrument, for example, during an electrosurgical procedure. A corresponding objective is to provide such improved systems, methods and devices, in an easy to use and effective manner, including easy implantation and use with known electrosurgical generators. In treating one or more of these objects, the present inventors have recognized that known radio frequency electrosurgical waveforms produce average bias voltages that are at least equal to and in most cases greater than 0 volts. In relation to this recognition, and in one aspect of the present invention, a surgical system is provided comprising the generation and application of a novel electric power waveform that provides a negative average bias voltage at the work surface (s). of an electrosurgical instrument in relation to a return trajectory. For purposes of the present, "average bias voltage" and / or "average bias voltage" are determined by integrating the voltage output on the work surface (s) in a single, continuous period of operation of at least about three. seconds, or during successive periods of operation of a total of at least approximately three seconds, and dividing the result between the continuous or cumulative periods of operation. As will be further described, the amount of an eschar deposit is significantly reduced using the novel negatively polarized waveform.

Additionally, any deposit that does not accumulate can be more easily withdrawn. In another aspect of the present invention, the system of the invention includes periodically applying an electrical signal to the work surface (s) of a surgical instrument and, at least partially and contemporarily, that the work surface contacts a means for facilitate the cleaning of deposits of the instrument. More particularly, the invention may comprise contacting the work surface or surfaces of an instrument that with an electrically activated conductive liquid to improve the removal capacity of the accumulated eschar on the work surfaces during electrosurgical procedures. Preferably, the work surfaces are maintained at a negative electric potential in relation to a conductive return electrode that is also in contact with the conductive liquid to establish a complete circuit. As will be described later, the aforementioned convenient cleaning effect occurs from the formation of gas bubbles in the work surface (s).; said bubbles act to separate, or "lift" deposits from work surfaces. The benefits of the aforementioned aspects of the present invention can be realized when the working surfaces of the electrosurgical instrument are made of traditional stainless steels commonly used for surgical instruments. The benefits can be improved by selecting materials from the work surface that contain elements that have standard reduction potentials that are positive with respect to that of a standard hydrogen electrode. For example, the use of one or more elements of Group I B of the Periodic Table of Elements, including copper, silver and gold, produces improved results. As mentioned, the use of an electrosurgical waveform that provides a negative average polarization voltage on the working surfaces of an electrosurgical instrument relative to the return path serves to reduce the buildup of eschar and reduce the degree of adhesion. In this regard, the inventors have found that the effect of reducing the accumulation of eschar and / or producing an escer easier to remove occurs even when there is a negative average polarization voltage of only about 1 volt between the working surfaces of a electrosurgical scalpel blade in relation to the return path device. More importantly, this negative polarization of the work surfaces can be put on known radio frequency energy source output waveforms (e.g., conventional electrosurgical generators) used to obtain predetermined coagulation and / or fabric cutting effects. As such, it should be understood that the substantial portions of the electric waveform applied to the work surfaces can be positive (ie, relative to the device of the return path) while the average voltage bias is negative (it is say, in relation to the device of the return path). In one approach, negative polarization can be achieved simply by changing known "downward" radio frequency waveforms via the serial interconnection of a low voltage direct current source (eg, approximately 10 to 120 volts) with a source of radio frequency electrosurgical energy. In another approach, a low frequency (LF) source (eg, = 10 KHz) output is combined with a conventional radio frequency electrosurgical power source output (eg = approximately 100 KHz) to produce a form of novel wave that has an average negative polarization. In such an approach, the components of the blocking and / or frequency-based derivative circuit may conveniently be employed as a means to electrically isolate each one of the radio frequency and low frequency sources. In still another approach, a radio frequency electrosurgical power source can be conveniently employed to provide a radio frequency output that is used by signal conversion means to generate a low frequency waveform that can be combined with the form of radio frequency wave to produce the desired negative polarization. Such signal conversion means may conveniently function to present a first resistance to the flow of current in one direction therethrough and a second resistance to current flow in the other direction therethrough, said first and second being different from each other. second resistance. Preferably, a control means is included to selectively and variably establish the difference between said first and second direction-dependent resistors. As will be appreciated, other characteristics of the new electric waveform (ie, that is not negative polarization) such as frequency and amplitude can be provided, as desired for cutting and / or coagulation as previously known in the design technique of the electrosurgical generator. Said frequencies may have a range of 100 kilohertz to 2 megahertz, and the peak-to-peak voltages may be in a range of between about 10 to 15,000 volts. In this regard, the new waveforms can be approximately sinusoidal, damped sinusoids or intermittent waveforms of approximately sinusoidal or damped sinusoidal shapes, as previously known in the art. The various components for implementing negative polarization characteristics of the present invention can be formed separately and / or incorporated and conformed with prior art electrosurgical generators. When a conductive liquid is sprayed onto the work surfaces while the work surfaces are activated with the new electrosurgical waveform, the amount of eschar deposited can be further reduced. This conductive liquid spray preferably comprises a biocompatible solution, including, for example, a normal saline solution. The spray mist can be applied using an external spray device separated from the surgical instrument or it can be integrated into the surgical instrument. When the conductive spray is used in conjunction with an electrosurgical instrument having work surfaces made of a predetermined group of materials, such as metals comprising copper, deposits of eschar do not accumulate appreciably and surgical procedures can proceed virtually without the need to remove deposits of eschar. As mentioned above, the removal of eschar from the working surfaces of a surgical instrument is facilitated in accordance with the present invention by contacting the surfaces with an electrically conductive liquid and applying a negative voltage polarization on the work surfaces relative to a return electrode that is also in contact with the conductive liquid. In this regard, the configuration of the invention can define, in essence, an electrolytic cell, wherein the working surfaces act as a cathode and the return electrode acts as the anode. During the operation, the current flows via ion transfer from the return (or positive electrode) through the conductive solution to the electrosurgical instrument (or negative electrode) with electrons flowing from the electro-surgical instrument to the return electrode. The return electrode may be connected to a power source terminal that predominantly has a positive polarity, and the electrosurgical instrument may be connected to a terminal of the same source of electric power having a predominantly negative polarity. The magnitude of the polarities (ie, voltages) may vary over time; however, higher voltages provide faster cleaning. By way of example, the removal of eschar occurs expeditiously when a voltage source of at least about 10 volts is used. Currently, a voltage between approximately 10 and 120 volts is preferable. In operation, chemical reactions occur at the electrodes, and, by selecting suitable components for the electrolytic cell, it is possible to cause gas bubbles to form. By way of example, gas bubbles may be caused to form on the working surfaces (or negative electrode) due to the electrolysis of substances in the electrically conductive liquid. In one configuration, the hydrogen gas bubbles can be made to evolve from the decomposition of water when the conductive solution is a saline solution, such as normal saline. Gas bubbles start as small accumulations of their constituent molecular entities and become larger as they continue to add more molecules. Gas bubbles are formed in several fractures and free spaces of the eschar that has formed as well as in the free regions of the working surfaces. When bubbles start in regions that are limited, such as small spaces adjacent or under the eschar, they are necessarily in a restricted volume and as the bubbles grow, they produce a force in the adjacent eschar that causes the eschar to move and eventually rise from the substrate of the work surface where the deposit of eschar was formed. Any residual adhesion of the eschar to the work surfaces comes from weak forces such as those caused by surface tension or van der Waals forces, and such weak forces are easily overcome by, for example, gentle rubbing. Thus, the deliberate formation of bubbles in the eschar, in this case using electrical energy, causes the eschar to loosen and withdraw or be easy to remove from the work surfaces. Preferably, in eschar cleaning / removal modes, the return electrode comprises one or more materials that do not corrode easily to discolor the conductive liquid and that do not substantially change the resistance, either up or down, of the cell. In particular, electrode materials that produce corrosion products that are attached to the electrode or that produce corrosion products that are substantially insoluble in the solution are desirable, including aluminum. The electrical energy used for cleaning purposes can be derived from the output of a conventional radio frequency energy source (eg, electrosurgical generator) or can be provided separately from an electrosurgical generator. In one configuration, the working surfaces of an electrosurgical instrument may be connected via a conductive element (eg, insulated wire) to the negative terminal of a direct current (DC) power source, such as a battery cell, and An aluminum return electrode can be connected to the positive terminal of the direct current energy source via a suitable conductive element (eg insulated wire). Alternatively, when a radio frequency energy source is employed, a rectification means may be used to provide a predominantly negative voltage in the electrosurgical instrument and a predominantly negative voltage in the return electrode. The rectification means may conveniently include one or more diodes, preferably with one or more transistor elements. Mechanical or electrical interrupting means may also be used to establish first and second circuit states that correspond to an electrosurgical procedure mode and a cleaning procedure. Electronic components for rectification, interruption, etc. one or more of the return electrode, the electrosurgical instrument, a cleaning assembly comprising the conductive fluid, or a separate device that interconnects one or more of these assemblies with each other or with the electrosurgical generator can be incorporated into the housings of one or more of the return electrode. In this way, the use of this aspect of the present invention also does not require modification of conventional electrosurgical generators to take advantage of the cleaning benefits. Preferably, the conductive liquid used for cleaning is one that is biologically acceptable, such as normal saline, although other biologically acceptable solutions such as ascorbic acid, sodium chloride and / or sodium bicarbonate solutions also produce the desired effect. The conductive liquid may be in an absorbent bearing, such as a gauze pad, which contacts a sheet of conductive metal that acts as a return electrode. In turn, the metal sheet is electrically connected to the positive terminal of a power source using a conductive element, such as an insulated wire. The conductive element keeps the metal sheet at a positive voltage relative to the work surfaces of the instrument from which the eschar is being removed. In one embodiment, a clip can be used to allow a moistened conductive metal sheet / bearing assembly to be removably attached to surgical drapes or other articles in the surgical region so that a surgeon can conveniently clean working surfaces through of the moistened bearing to simultaneously loosen and clean the deposits of eschar from the work surfaces in one movement. Alternatively, the conductive liquid may be contained in a small container, wherein the liquid is electrically interconnected via separate conductive elements (eg, via separate insulated wires) to the positive and negative terminals of a voltage source. In one approach, the container may be configured or an insert element (e.g., a multi-layered woven bearing) may be provided to define a tortuous entry path that allows selective access of a surgical instrument to the container while retaining substantially the liquid in it. In another approach, one or more sealing members (e.g., elastic fins or resealable material) may be used. In any case, the working surfaces of a surgical instrument can be selectively inserted into the container to contact the conductive liquid and, when removed, the insert member or sealing member can contact and facilitate the removal of any eschar that can be removed. be adhered loosely to the work surfaces. Conveniently, the activation of the delivery of the negative voltage to the liquid can be triggered automatically using switches activated by the presence of the surgical instrument or its work surfaces or by using an automatic sensor that determines when the work surfaces are in contact with the conductive liquid. More particularly, a detection signal, such as a low voltage alternating current signal or a specific frequency different from that used to obtain an electrosurgical effect, can be transmitted to the surgical instrument and its work surfaces, and they can use sensors that monitor the positive voltage conductive element to detect the presence of a signal of this type, which would be present only when the work surfaces are electrically communicating with the positive electrode in the cleaning element, such as an electrode aluminum, via the work surfaces that contact the conductive liquid. Alternatively, an automatic or similar interruption detection may be employed to provide the conversion of an electrosurgical procedure mode to a cleaning mode when the radio frequency electric power source is operating in the electrosurgical procedure mode. The interruption can be carried out using one or more mechanical switches comprising one or more moving elements that produce the opening or closing of one or more electrical contacts, or the interruption can be achieved using an electronic switch comprising one or more electronic components that activate or deactivate current flow paths (eg, automatically). It should be noted that electrosurgical procedures do not have to occur with the use of the aforementioned average negative polarization aspects of the invention to achieve the benefits via the use of the cleaning related aspects of the present invention. That is, even when only known electrosurgical techniques are used, the removal of eschar will still be facilitated when the working surfaces of an electrosurgical instrument are kept at a substantially negative voltage and when they make contact with a conductive liquid that is maintained at a relative voltage positively positive However, cutting with the novel waveform mentioned above produces an eschar that is much more easily removed. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates an example of a waveform of the prior art (ie, output by an electrosurgical generator of the prior art). Figure 2 illustrates an example of a novel electrosurgical waveform comprising the present invention, said waveform comprising a waveform of the prior art combined with a negative polarization waveform. Figure 3 is a block diagram illustrating an approach for producing a negatively polarized waveform in a monopolar electrosurgery application, wherein a first radio frequency (RF) source and a secondary low frequency (LF) source produce two electric waveforms that are combined. Figures 4A-4C illustrate topologies of electrical circuits of various modalities corresponding to the block diagram of Figure 3. Figures 5A-5E illustrate various embodiments of an alternative approach to produce a negative polarized waveform in an electrosurgery application. monopolar, where a radio frequency source is used that is conditioned to provide a low frequency waveform for negative polarization. Figures 6A-6F illustrate various modalities for selectively using a radio frequency electrosurgical source to clean an electrosurgical instrument. Figure 7 illustrates the manner in which a monopolar electro-surgical system can be configured with a cleaning bearing connected to ground to facilitate the removal of eschar from an electrosurgical instrument. Figure 8 illustrates an inserted cleaning element in which work surfaces can be immersed in an electrically conductive liquid to facilitate the removal of eschar from an electrosurgical instrument. Figure 9 illustrates a modality having radio frequency and low frequency sources for cleaning and electrosurgery procedures and including detection control means for alternating between such procedures. DETAILED DESCRIPTION OF THE INVENTION Figure 1 illustrates a radio frequency electric waveform generated by a known electrosurgical generator for tissue cutting. As shown in, the average voltage bias for the illustrated operating period is greater than zero volts. Figure 2 illustrates an electrosurgical waveform comprising an aspect of the present invention. In particular, Figure 2 illustrates a novel waveform made when an intentional negative polarization is placed on a known waveform by moving or moving the known radio frequency waveform of Figure 1 with a voltage component of negative direct current. As will be appreciated, a negative polarization can also be applied by changing the shape of the known radio frequency waveforms. In any case, the net result is that the average voltage bias is negative. Although one modality can employ both waveform formation and waveform change media, anyone can be used by him alone to achieve the desired effects. For purposes of describing the first aspect of the present invention, Figures 3-5 show the manner in which a monopolar electrosurgical system can be configured to produce negatively polarized electrosurgical waveforms. Without loss of generality, it is recognized that there are other modalities than those illustrated and that can be derived from the principles illustrated in Figures 3 to 5 and the descriptions contained herein. In the various figures presented below, the components having the same reference numbers provide the same functionality or an analogous one. Figure 3 is a block diagram of a negative polarization approach comprising an alternating current electric source of radio frequency (RF) 1 (eg, = 100 kHz) and a source of low frequency electric power ( LF) 2 (for example, = 10 kHz) having their combined electrical output waveforms using suitable circuits 3 to produce an output to an electrosurgical instrument 4 from which electrical power is applied to a patient 5. The electrical circuit is completed by having the patient 5 contact a return path electrode 6 which continues via the electric return path 7 to the radio frequency energy source 1. The radio frequency energy source 1 commonly operates between approximately 250? - 5 kilohertz and 2 megahertz, and commonly has open-circuit peak-to-peak voltages of approximately 2,000 to 15,000 volts and peak-to-peak voltages during use ranging from 600 volts at 15,000 volts. Radio frequency electric waveforms can be approximately sinusoidal, sinusoidal damped or intermittent waveforms of approximately sinusoidal or damped sinusoidal shapes. The means for producing said radio frequency electric waveform are known to those skilled in the art of electrosurgical generator design. The low frequency energy source 2 is illustrated as a variable device and can produce a low frequency electric waveform that varies in time. Without loss of generality, Ial2 can also be a direct current source that produces substantially direct current (for example, from a battery or a isolated power supply). A source is desired that adds a negative polarization of at least 1 volt to the output of the radio frequency energy source 1. Additionally, for many applications it may be preferred that the negative bias source includes a negative bias control device to provide more than one polarization value.

A value would produce a negative average voltage polarization of, for example, approximately 1.5 volts, when combined with the electric waveform of the radio frequency energy source 1. This value would be used to reduce the accumulation of eschar and produce a Escerra that is easily removed. The higher negative bias values would be available to further reduce the amount of eschar formed, with said biases in a range greater than about 60 negative volts. A negative average voltage polarization of approximately 3 to 16 volts is currently preferred. Practical limits on the amount of negative polarization to be used can be determined as appropriate to maintain the safety of the health personnel and the patient. In this regard, the desired effects of reduced deposits of eschar have been obtained with voltages of more than 60 volts of negative average polarization, these results are not practically different from those observed at much lower voltages. The low frequency energy source 2 in Figure 3 can also be used for instrument cleaning (assembly not shown in Figure 3). In this regard, various cleaning modalities will be described in detail below. Generally, for cleaning purposes, a value of the low frequency energy source 2 between approximately 10 negative volts at 120 negative volts is currently preferred to achieve a rapid scab removal. During the operation for the removal of eschar, the radio frequency energy source 1 does not have to continue generating its electrosurgical waveform. However, the removal of eschar is not adversely affected if a radio frequency electrosurgical waveform is used in conjunction with a low frequency waveform. The radio frequency energy source 1 and the low frequency energy source 2 can be controlled so that they apply power when they are turned on using manually operated controls in the electrosurgical instrument 4 and / or controls in a separate device such as a power switch. foot. Such control means are known to those skilled in the art. Additionally, and as described below, the controls can be incorporated so that each time the radio frequency energy source 1 is activated, the low frequency energy source 2 is activated at the same time, and so that the source of low frequency energy 2 can be operated without the radio frequency energy source 1 being active. Additional control means will allow the low frequency energy source 2 to produce electrical waveforms, such as those using a low voltage, when activated in conjunction with the radio frequency energy source 1 and another waveform, such as as those that use a high voltage, when operating without the radio frequency energy source 1. Said operation could be used during the cleaning procedures for the removal of eschar.

Figure 4A illustrates a circuit mode for combining the outputs of the radio frequency energy source 1 and the low frequency energy source 2. A low frequency bypass filter 8 (e.g., = 10 kHz) and a filter high-frequency shunt 9 (for example, = 100 kHz) are provided in the circuit. The circuit also includes a low frequency blocking capacitor 10 (e.g., = 10 kHz) and a high frequency blocking inductor 11 (e.g., = 100 kHz). The bypass filters 8, 9 and the blocking components 10, 1 1 are used as isolation means to protect the radio frequency energy source 1 from the effects of the low frequency energy source 2, and to protect the The low frequency energy source 2 of the effects of the radio frequency energy source 1. More than one of each type of bypass / block element can be used to improve performance or reduce cost. The output of the surgical instrument 4 comes from a socket 32 in an inductive coupler 12. The "load" of the system is represented by a patient load 13. Figure 4B illustrates another circuit modality for combining the outputs of the power source of the patient. radio frequency 1 and the low frequency energy source 2. The low frequency bypass inductor 14 and the high frequency bypass capacitor 15 are included. The low frequency signal path 16 (ie, from / to the low frequency energy source 2) and the high frequency signal path 17 (ie, from the radio frequency energy source 1) are shown. Both trajectories pass through the electrosurgical instrument 4 to the patient (represented as load 13) adding or combining the wave forms of electric energy of the radio frequency energy source 1 and the low frequency energy source 2. The f ? 5 low frequency blocking capacitor 10 protects the radio frequency energy source 1 from the low frequency power source 2. The high frequency blocking inductor 1 1 protects the low frequency power source 2 from the source Radio frequency energy 1. The low frequency blocking capacitor 10 may be one or more of the output blocking capacitors normally found in known radio frequency electrosurgical generator output circuits. Figure 4C illustrates the manner in which multiple bypass components 14, 15 and locking components 10, 1 1 can be coupling in series to form a more efficient circuit. The advantages include a more effective isolation of the radio frequency energy source 1 and the low frequency energy source 2 between them. Additionally, the capacitance of the series capacitors 10 can be established to conveniently reduce the stimulation neuromuscular. More particularly, if a blocking capacitor 10 adjacent to the electrosurgical instrument 4 is very large, then the formation and rupture of contact between the instrument 4 and the patient load 13, as occurs routinely during surgical procedures, causes store a substantial load on the blocking capacitor 10. Such a substantial charge can cause neuromuscular stimulation. This effect can be reduced or otherwise substantially avoided by using a plurality of blocking capacitors 10 in a series configuration, each of these capacitors having a suitably small value. Figures 5A-5E illustrate various embodiments using a radio frequency signal waveform to generate a low frequency signal waveform that is combined with the radio frequency signal to produce negative bias (i.e., a polarization) of negative average voltage). In particular, Figure 5A illustrates an embodiment in which the core of an inductor 50 is provided with a permanent magnet 52 to produce a negatively polarized low frequency signal component that is combined with a radio frequency signal component of the source of radio frequency energy 1 and is provided to the electrosurgical instrument 4. More particularly, the core of the inductor 50 may comprise a saturable iron powder ring having a portion thereof replaced with a permanent magnet. The polarity of said magnet provides a differential saturation that depends on the direction of the signal through it. The inductance of the inductor 50 is opposed to the inverse magnetic fields induced by the nature of the alternating current of the electric current produced by the radio frequency energy source 1. However, the magnetic polarization produced by the permanent magnet 52 causes the induced opposition of the inductor 50 to preferentially favor current flow in one direction and preferably to oppose the flow of current in the opposite direction. The net result is a greater voltage drop in one direction than in the other, which in the illustrated configuration causes a negatively polarized voltage to be applied to the instrument 4. Figure 5B illustrates another modality in which the source of The waveform of low frequency electrical energy is derived from the radio frequency energy source 1. A low frequency step element 18 provides a path for the low frequency signal coming from a rectifier 1 9. The voltage of the waveform is adjusted using the voltage adjusting element 20. The voltage adjusting element 20 it can be one or more electronic elements such as resistors or capacitors or a set of one or more of these electronic elements. The rectifier 1 9, which may be one or more diodes and associated filter elements such as capacitors, defines a low resistance path for the current flowing in one direction and a high resistance path for the current flowing in the opposite direction . The voltage relief element 20 provides a resistance equal to the current flow in both directions. The result is a preferential current flow for a predetermined direction, which in the polished configuration causes a negatively polarized voltage to be applied to the electro-surgical instrument 4. Figure 5C uses another additional modality in the which the source of the low frequency electric power waveform is derived from the radio frequency energy source 1. A high frequency block 21, a high frequency branch 22, and the # Rectifier 19 form a voltage divider that produces a low polarized direct current voltage. The bias voltage depends on the impedance values of the radio frequency block 21 and the radio frequency derivation 22. For example, when selecting the impedances of the radio frequency block 21 and the radio frequency derivation 22 using design principles In known cases, the voltage that falls through these elements can be used to produce a wide range of polarized voltages. Typical values can be approximately 100 microhenries / for the radio frequency block 21 and 10 picofarads for the radio frequency derivation 22, with the resulting polarization depending on the frequency of the radio frequency energy source 1, but which can be determined using methods known to those skilled in the art. Figure 5D illustrates a similar configuration. Figure 5E illustrates a further embodiment in which the wave form of low frequency electrical energy is derived from a radio frequency source 1, which in this case can again be a standard electrosurgical generator having a capacitor internal lock 54. The circuit additionally uses a transistor 56, a resistive control element 58, a diode 60 and a resistor 62. When the electrosurgical generator 1 is operating, the diode 60 serves to cause a positive polarization to occur in the line of the circuit 59 between the diode 60 and the transistor 56. The level of said polarization is determined by the resistance values of the resistive control element 58 and the resistor 62. Said polarization can be conveniently set selectively since the resistive control element 58 is controllable. With regard to another aspect of the present invention, Figures 6A-6F illustrate various embodiments for cleaning or removing scab that may accumulate on the work surfaces of an electrosurgical instrument 4. For purposes of description, a monopolar configuration with an electrosurgical generator conventional 1 and a common electrosurgical instrument 4 are used, wherein the instrument 4 is illustrated as being in electrical contact with either a patient 5 or a cleaning assembly 64 (ie, illustrated by interrupted lines) as will be selectively determined by manipulating the user of the instrument 4. Those skilled in the art should recognize that the embodiments of Figures 6A-6F illustrate principles that can be applied to a wide range of applications and that such principles are not limited to monopolar applications.

Figure 6A specifically illustrates an embodiment in which a conventional electrosurgical generator 1 provides an electrosurgical waveform to the electrosurgical instrument 4 for electrosurgical procedures when the mechanical switch 70 is closed, and which provides electrical power to clean the electrosurgical instrument 4 when the Mechanical switch 70 is selectively opened (for example, by a user). In this embodiment, the electrosurgical generator 1 includes a blocking capacitor 54 internal thereto. The line of the return electrode 7, interconnected to the return electrode 6, as well as the energy line 61, which can be interconnected to the electrosurgical instrument 4, can terminate to simple connectors or connections (not shown) which in turn can be interconnected selectively to the electrosurgical generator 1. As will be appreciated, said configuration accommodates the easy use of conventional electrosurgical generators. The voltage establishment capacitors 93 and the bridge rectifier 90, which comprises the diodes 91, collectively serve to establish a voltage delivered to the electrosurgical instrument 4 via the cleaning energy line 95, as well as to rectify said voltage for cleaning purposes. . A filter capacitor 92 smoothes the output voltage to the cleaning power line 95. Using the voltage clamp capacitors 93 (instead of a resistor) avoids heat dissipation management considerations. The filter capacitor 92 produces voltages that consistently remain above zero volts, thereby facilitating the operation of the cleaning assembly 64 when the electrosurgical instrument 4 is selectively contacted with the cleaning assembly 64. As mentioned above, the mechanical switch 70 is closed during normal surgical procedures. The switch 70 is opened when the user wishes to clean the electrosurgical instrument 4. The mechanical switch 70 can be conveniently incorporated as a separate button on the handle of the electrosurgical instrument 4, such as the handle of an electrosurgical pencil, alternatively the mechanical switch 70 could be incorporated in the cleaning assembly 64. Figure 6B illustrates a configuration having a radio frequency energy source 1, such as a standard electrosurgical generator, which internally includes a blocking capacitor 54. In this configuration, the blocking capacitor 54 is used to produce a suitably polarized current for cleaning the electrosurgical instrument 4 using a cleaning assembly 64. For purposes of illustration, the blocking capacitor 54 is shown connected to the line 7 between the return electrode 6 and the power source. radio frequency 1. Alternatively, the capacit or blocking 54 could be connected to line 61 between source 1 and electrosurgical instrument 4. As will be appreciated, power supply line 61 and return line 7 can each end in suitable connectors or connections (not shown) ) for selective and easy interconnection with a standard electrosurgical generator when used as a source 1. In the illustrated mode, the voltage establishment resistor 66 and the diode 60 generally establish the voltage produced for cleaning and serve to rectify said voltage. The bypass resistor 68 is beneficial because it reduces the total voltage that the diode 60 needs to support when the electrosurgical instrument 4 is not in electrical contact with the cleaning assembly 64 or the patient 5. In this regard, the bypass resistor 68 is it selects so that its resistance is greater than that represented by the cleaning assembly 64. By way of example, when the cleaning assembly 64 is designed to present a resistance of 200 ohms, the bypass resistor 68 could have a resistance of about 500 ohms or more. Additionally, the resistance of the bypass resistor 68 should be selected in conjunction with the breakdown voltage specifications of the diode 60, the output voltage characteristics of the electrochemical generator 1, and the resulting drop in voltage that would occur through the set-up resistor. voltage 66. The mechanical switch 70 is provided for selective activation of a user when the user wishes to clean the electrosurgical instrument 4. By way of example, the mechanical switch 70 could conveniently be located as a separate button on the handle of the electrosurgical instrument 4. One or more blocking capacitors 72 may be included to block the polarized electrical power flowing through the patient 5 in the event that a user operates the mechanical switch 70 and contacts the patient 5 with the electrosurgical instrument 4. In this case , the desired electrosurgical effect would occur in the It is usual with a slight reduction in the applied energy due to the derivation of the electric power through the voltage setting resistor 66, the diode 60 and the bypass resistor 68 via the mechanical switch 70. Figure 6C illustrates a similar embodiment. to that shown in Figure 6B. In this mode, the electric power is again G 9 5 uses the electrical energy of the electrosurgical generator 1 and is applied via the mechanical switch 70 closed to clean the eschar of the electrosurgical instrument 4. In this mode, the capacitor 93 and the diode 60 are used to generally establish the voltage produced for cleaning and to rectify said voltage. A filter is defined by diode 63 and capacitor 92 for smoothing the output voltage delivered to cleaning assembly 64. The use of voltage-setting capacitor 1 1 (instead of a resistor) avoids the need to dissipate considerable heat. The filter (defined by diode 63 and capacitor 92) produces an output voltage to the set of cleaning 64 which consistently remains above zero volts, thus facilitating the operation of the cleaning assembly 64 when the electrosurgical instrument 4 is in electrical contact therewith. During surgical procedures, mechanical switch 70 is open and the return current path is a through the return electrode 6. The mechanical switch 70 closes when a user wishes to clean the electrosurgical instrument 4. Again, the mechanical switch 70 may conveniently be located on the mains of the electro-ironic pen or be incorporated in the electrode. the lim head assembly 64. 25 As will be appreciated, the various electronic components and components of the mechanical switch shown in Figures 6B and 6C can be incorporated in the electrosurgical generator 1, a set for the return electrode 6, an assembly for the electrosurgical instrument 4, or in combinations of the above. For example, all of the electronic components shown in Figure 6B, with the exception of the blocking capacitor 72, could easily be incorporated in a connector for the electrosurgical instrument 4 that is connected to the electrosurgical generator 1. The blocking capacitor 72 could easily be incorporated into a connector for the return electrode 6 which is connected to the electrosurgical generator 1. Alternatively, all these components could be included in a connector that would serve to connect the electrosurgical instrument 4 and the return electrode 6 in the electro-surgical generator 1. Figure 6D illustrates another modified version of the configuration of Figure 6B. In Figure 6B, the voltage difference across the period 60 is used to provide a substantially positive voltage on the line 69 connected to the cleaning assembly 64, relative to a substantially negative voltage on the energy line 61 to the electrosurgical instrument 4. The unidirectional flow of current through the diode 60 causes the blocking capacitor 54 to polarize and produce a time-varying voltage waveform in the cleaning set 64 that is positive with respect to the voltage in the electrochemical instrument 4. In order to provide a selective cleaning and otherwise prevent a short circuit of the return electrode line 7 to the supply line '61, an electronic automatic interruption element 70 may be employed. More particularly, / * * said electronic interruption element 70 may comprise one or more components such as a bipolar junction transistor, an insulated gate bipolar transistor, or a metal oxide semiconductor field effect transistor. When the electrosurgical instrument 4 is not in contact with the cleaning assembly 64, the switch 70 effectively blocks the entire flow of current through the line to the diode 60. When the electrosurgical instrument 4 makes contact with the cleaning assembly 64, the current flows from the instrument 4 to the cleaning assembly 64 and the switch 70 allows the current to flow. Figure 6E shows another additional modality where can provide a bipolar junction transistor 56 and two resistors 74 and 76 to provide the interrupting function of the switch 70 in Figure 6B. The resistor 76 is selected to provide a relatively large resistance for the flow of current during the normal operation of the generator 1 (ie, when the instrument 4 is not in contact with the cleaning assembly 64) through the diode 60 is relatively low. During the normal operation of the generator, the current flow through the resistors 74 and 76, while low, causes the cleaning energy line 69 to be positively biased compared to the return line 7, and is polarized even more positively as compared to the supply line 61. The resistor 76 is further selected so that during the normal operation of the generator 1, the voltage difference between the base and the emitter of the transistor 56 does not exceed that which would cause the transistor 56 turns on. During cleaning, the electrosurgical instrument 4 contacts the cleaning assembly 64 and causes the voltage in the cleaning line 69 to drop, changing the voltage difference between the base and the emitter of the transistor 56 to exceed the predetermined value necessary for turn on the transistor. As will be appreciated, various circuit elements may be added to the configurations of Figures 6A-6E to control the current or voltage used for cleaning. As for Figure 6E, said control elements can include any circuit component that will serve to moderate the magnitude of the control signal provided to transistor 56, or an alternative transistor configuration. Said transistor configuration can be defined by one or more electronic components, at least one of which has an electrical conductivity through its input and output controlled by the voltage or current applied to one or more lines. By way of example, transistors suitable for the present invention include one or more bipolar transistors, isolated gate bipolar transistors, or metal oxide semiconductor field effect transistors, although other devices could be employed including vacuum tubes or switches of mechanical relay as mentioned above.

As will be appreciated by those skilled in the art, when the transistor is being used as a bipolar transistor, the control component should be a resistor that controls the current flow at the base of the transistor. Instead of using an electronic or mechanical switch element to control the flow of electrical energy, as in the configurations of Figures 6A-6E, a multi-element cleaning assembly 64 can be employed as shown in Figure 6F. Said assembly 64 includes one or more electrically conductive elements that are directly or indirectly connected either to the line of the return electrode 7, the supply line 4 or both lines. In this embodiment, the cleaning assembly 64 includes an upper conductor 80 and a lower conductor 82 that are connected to the opposite ends of the diode 60. In this configuration, the electrosurgical instrument 4 can be inserted into the cleaning assembly 64 (to establish the electrical contact with the upper conductor 80, thus completing an electrical circuit through the diode 60). When the electrosurgical generator 1 is operating, the unidirectional current flow through the diode 60 causes a substantially positive voltage to accumulate in the blocking capacitor 54. Said accumulation in turn provides a substantially positive voltage in the upper conductor 80 with respect to to the voltage in the lower conductor 82. The eschar in the electrosurgical instrument 4 is then immersed in a conductive liquid 84 which is contained in a housing defining the cleaning assembly 64. The current flows between the lower conductor 82 and the submerged portion of the electrosurgical instrument 4 causing the eschar in it to be released. If a porous member (not shown) is provided for retaining the electrolyte solution 84, said material can be used for coupling with the electrosurgical instrument 4 (i.e., in a cleaning action) to facilitate the removal of the loosened eschar. Alternatively, an internal insulating member 86 can be used for these purposes. To this aspect, the upper conductor 80 in the cleaning assembly 64 is prevented from contacting the electrolyte solution 84 by the insulating member 86. Likewise, the conductive portion of the submerged electrosurgical instrument 4 is prevented from contacting the lower conductor 82 by the mechanical barrier 90. Although the mechanical barrier 90 avoids physical contact, it allows the electrolytic current to pass through it. In this regard, for example, the mechanical barrier 90 could be a porous plastic screen with small openings that do not allow it. pass the submerged portion of the electrosurgical instrument 4, but allow the electrically conductive (ie, charged) components of the conductive liquid solution to pass through. The upper insulator 86 may be of similar construction (although it is not immersed in the electrolytic solution 84). The lower conductor 82 is insulated to the outside by the provision of the lower insulator 88, thus facilitating safe handling of the accommodating cleaning assembly 64.

Figure 7 illustrates a mode in which a radio frequency electric waveform generator 24 capable of producing radio frequency waveforms suitable for use in ^ Electrosurgery is connected via the electrically isolated cable conductive 25 to the electrosurgical instrument 26. A waveform biasing device 40 may be included between the radio frequency source 24 and the instrument 26 to provide a low frequency waveform and to combine the radio frequency waveforms and low frequency, as described above in relation to Figures 5A-5E. Additionally, the waveform biasing device 40 can provide for use of the radio frequency generator 24 for use in the cleaning of the electrosurgical instrument 26 using a cleaning assembly 33, wherein the circuit components are of according to Figures 6A-6F which are incorporated in the device 40. Attached to the electrosurgical instrument 26 is the metal cutting element 27. When it is activated, the Metallic cut 27 applies energy to the tissue of patient 5 and electrical circuit 20 is completed via the return path electrode 6 and the conductive wire of the return path 31. As mentioned, the cleaning assembly 33 may be included to clean the metal cutting element 27. For purposes of illustration, the cleaning assembly 33 comprises a 25 'cleaning pad 28, although other configurations are possible. The cleaning pad 28 may comprise a fibrous material that is moistened with a conductive, biocompatible solution (eg, normal saline solution and for solutions including ascorbic acid). For example, the cleaning pad 28 may be made of woven or non-woven absorbent materials (eg, gauze). The cleaning pad 28 is attached to an electrically conductive carrier 29 (for example, a sheet metal member). The faces and edges of the electrically conductive support 29 that do not contact the cleaning bearing 28 are preferably insulated with an electrically non-conductive material (not shown for clarity). The electrically conductive support 29 is electrically connected via the conductive element 30 to the conductive wire of the return path 31, and the device 40 for operation as set forth in relation to FIGS. 6A-6F. The metal cutting element 27 includes waveforms that contact or are in close proximity to the tissue. Said surfaces are made of one or more electrically conductive materials and may be partially or completely covered with a non-metallic coating which could impart desirable surface properties, such as adhesion resistance, although adhesion resistance is not generally needed with many. aspects of the present invention to facilitate the removal of eschar. The metal cutting element 27 can be made of stainless steel, as is traditional for working surfaces of the surgical instrument.

The improved performance in the form of scab accumulation is more easily removed or reduced when the metal cutting element 27 contains one or more materials having standard reduction potentials that are positive with respect to that of a standard hydrogen electrode. Selected elements of group IB of the Periodic Table of Elements are preferred, including copper, silver and gold. The working surfaces of the cutting element 27 can consist entirely of materials having positive standard reduction potentials with respect to that of the standard hydrogen electrode, or alloys containing these combined materials. For example, excellent results occur with copper-based alloys comprising 98 percent copper, bronze which is approximately 70 percent copper and 30 percent zinc, or bronze that is approximately 95 percent copper, including phosphorous bronze. The cleaning bearing 28 with its electrically conductive metal sheet holder 29 and conductive element 30 may be packaged together in a product to maintain sterility during shipping and storage. These elements could be packaged separately or included as part of a sterile package that also contains the return path electrode assembly 6 and the conductive wire of the return path 31. Alternatively, the cleaning bearing 28 with its electrically conductive metal sheet holder 29 attached and the conductive element 30 could be part of a package containing the electrically conductive insulated cable 25, the electrosurgical instrument 26, and the metal cutting element 27. In one embodiment, the cleaning bearing 28 may be pre-moistened with the electrically conductive solution and packaged with its electrically conductive metal sheet holder 29 attached in a sealed package which prevents the pre-moistened bearing 28 from drying out. This sealed package could be included as part of another package. In an embodiment, the previous wetting is done with normal saline, although other solutions, including ascorbic acid, are effective. The assembly consisting of the cleaning bushing 28 and its electrically conductive metal sheet carrier 29 may have another bonded support material. The additional support in one embodiment would provide an electrically insulating surface on all exposed edges and the back of the conductive sheet holder 29. Additional support in additional modalities would make the assembly "rigid" for ease of use if a surgeon wishes to press the work surfaces against the moistened bearing 28 and clean the work surfaces against the bearing. Alternatively, this assembly can be left flexible so that a surgeon can pick it up and bend the bearing 28 around the work surfaces to clean them. The assembly may also have a mechanism, such as a cloth clip 37, attached to its back so that the assembly can be connected removably to cloths or other suitable items for use by medical personnel. These mechanisms could include devices with one or a plurality of hooks, such as those in brooch and loop fasteners. Figure 8 illustrates another embodiment of a cleaning assembly 33, the access cover 32 connects to a container body 33, which contains conductive liquid 34 and is sealed at the bottom with the lower cover 35. The access cover 32 has a slot or other suitable opening 39 which allows the metal cutting element 27 to pass and be immersed in the conductive liquid 34. The conductive liquid 34 can be maintained in a structure (not shown) such as a sponge, which prevents it from flowing out through the opening 39 in the access cover 32. The material adjacent to the opening 39 in the access cover 32 is preferably selected to collapse around the metal cutting element 27 as the metal cutting element 27 is inserted / removed, and otherwise serves to seal the opening 39. By making contact with the metal cutting element 27, the edges of the opening 39 in the access cover 32 can facilitate the removal of the eschar by cleaning the cutting element. 27. Said features can be provided using a variety of means, including making the access cover 32 of a flexible or elastomeric material that deforms when it is under the contact force of the metal cutting element 27 and returns to its sealed position when It is not under force. In a fashion, the conductive liquid 34 is normal, although other solutions, including ascorbic acid, are effective. The conductive liquid 34 is in direct electrical contact with the conductive element 30, in which case the conductive element 30 passes through the lower cover 35, or is in indirect electrical contact with the conductive element 30, in which case the conductive element 30, is connected to the outside of the lower cover 35, which in turn it would be electrically conductive with an external insulating member placed there (not shown). The assembly can be shipped in a package (not shown) that maintains sterility during shipment and storage. These elements could be packaged as a separate assembly or included as part of a sterile package that also contains the return path electrode assembly 6 and the conductive wire of the return path 31 shown in Figure 7. Alternatively, the assembly could being part of the package containing the electrically conductive insulated cable 25, the electrosurgical instrument 26, and the mechanical switch 70 shown in Figure 7. The assembly may also have a mechanism, such as a cloth clip, attached to its back for that the assembly can be connected removably to cloths or other suitable items for use by medical personnel. Such mechanisms could include devices with one or a plurality of hooks, such as those of the hook and loop fasteners. Figure 8 illustrates having the lower cover 35 connected to the conductive element 30 so that the electric return path is external to the cleaning assembly 33. In another embodiment, the access cover 32 can be conductive, having a conductive sheet layer (not shown) which in turn is connected to a terminal of a substantially direct current source (not shown). The other terminal of the substantially direct current source is connected to the conductive element 30. When the metal cutting element 27 passes through the access cover 32 it takes on the polarity of the access cover 32 and when the metal cutting element 27 it makes contact with the conductive liquid 34 the electrical circuit that facilitates the removal of eschar is completed. The conductive liquid 34 can be maintained in a structure (not shown) such as a sponge, which prevents it from flowing out through the opening in the access cover 32. Figure 9, schematically illustrates the inclusion of controls in a modality for detecting when contact occurs between the working surfaces of an electrosurgical instrument 26, such as the metal cutting element 27, and the electrically conductive solution in a knife cleaning apparatus 36 (eg, such as the cleaning bearing 28). of the modality of Figure 7). Such controls could be implemented by, for example, detecting when there is a low impedance path between the metal cutting element 27 and the blade cleaning apparatus 36. Such detection could occur, for example, using a support generator 37 to produce a detection signal (for example, 100-200 kHz AC or other variable signal in time) that goes through a detection signal output conductor 38 and that has a return to ground with the grounding conductor of the circuit detection 39. The detection signal output conductor 38 and the grounding conductor of the detection circuit 39 are connected to a circuit module 37 comprising a control logic device 43 and a subcircuit 45 for combining the output of the radio frequency source 1 and the low frequency source 2 (in accordance with Figures 5A-E). The control logic device 43 in the circuit module 47 will control when the radio frequency energy source 1 and the low frequency energy source 2 operate and for example, would cause both to operate concurrently during surgical procedures to combine their outputs for negative polarization using the signal combining subcircuit 45. The detection signal is selected to work correctly in the environment of use. For example, could have a frequency in the range of 100 to 200 kilohertz and be limited to a current that does not exceed 5 milliamperes. The detection signal is sent to the metal cutting element 27 via the electrically conductive insulated cable 25 and the electrosurgical instrument 26 and the resistance of the returning signal is detected from the return path formed by the knife cleaning apparatus 36, the conductive element 30, and the conductive wire of the return path 31. The generator of the detection signal 37 produces the detection signal except when the radio frequency energy source 1 is operating.

When the radio frequency energy source 1 is operating, the output of this detection signal generator 37 is stopped with a closing signal from the generator of the detection signal 41. When the metal cutting element 27 contacts the conductive solution in the blade cleaning apparatus 36 a low impedance return path for the detection signal is created. When the metal cutting element 27 is not in contact with the conductive solution, the circuit of the detection signal is open, thus presenting a very high impedance return path for the detection signal. The controls in the circuit 45 for combining the radio frequency and low frequency sources and the detection signal and the control logic device 43 detect the low impedance path and activate the low frequency source 2 using a level control signal voltage of the low frequency source 42 to produce an electric waveform with a negative bias voltage of greater range from about 30 negative volts to negative 130 volts. The radio frequency source 1 would not activate. The automatic activation of the low frequency source 2 in the larger range would apply the electric waveform to the instrument 26 necessary for the removal of the eschar using the apparatus 36. One mode would prevent the low frequency source 2 from producing a negative bias voltage high except when the work surfaces, such as the metal cutting element 27, contact the electrically conductive solution in the cleaning apparatus 31.

This control prevents doctors from inadvertently applying negative voltage polarization electric waveforms to patient tissues. f For example, the control logic device 43, detects when the work surfaces 27 contact the cleaning apparatus 38 by detecting the presence of the detection signal in the conductive return path 31 using a detector circuit employing suitable combinations of high pass and low pass filters to attenuate the signals with frequencies above and below those of the signal detection. The amplitude of the filtered signal could be used, possibly in combination with suitable amplifiers, such as an input to a level detector to determine if the detected detection signal is strong enough to establish that the working surfaces are making contact. with the cleaning device. The level detectors could include, for example, voltage comparators that use a reference voltage as a level that is compared to an amplified filtered detection signal. If the detection signal is sufficiently P strong then the level detector will produce an output signal 20 that activates a circuit breaker that directs cleaning energy to the electrosurgical instrument. Likewise, if the strength of the filtered signal is less than that required for the level detector to produce an output signal that activates a switch circuit to clear the control logic circuit, then the logic circuit The control circuit activates the interruption circuits that lead to normal electrosurgical device operation, which includes operating the radio frequency energy source 1 and the low frequency energy source 2, as mentioned above, the circuits that generate the detection signal could be used to simultaneously produce the comparison signal so that not only the proper amplitude but also the appropriate timing of the detection signal is used to establish whether the work surfaces are in contact with the cleaning apparatus. The detection of amplitude and timing can improve the reliability of the automatic detection logic. This approach can be particularly effective when the detection signal is generated in a manner other than a continuous wave, such as if there are times when the signal is present and occasions when the signal is absent and a comparison circuit checks that the presence and absence of the detection signal occurs at the correct times. A spray element that produces a vapor of a conductive biocompatible substance can be incorporated into the surgical instrument 26, as taught in the United States Patent.

P of North America Serial No. 5, 554, 172, incorporated herein by reference in its entirety, or the vapor can be generated and applied using a separate device. Employing this vapor while applying electrical power during surgical procedures is known to those skilled in the art. However, the use of said spray or vapor with a negative average polarization waveform for electrosurgery is novel. This configuration of the invention produces improved additional results. OPERATION The use of the present invention will be described in the context of the embodiment of Figure 9 for monopolar short. It can be easily seen that the invention could be used with other types of surgical procedures. As such, the invention is not limited to the described application. In use, the medical professional would follow a standard practice and prepare the surgical site in the usual way. The electric waveform generator 1 provides a plurality of energy values for the appropriate selection depending on the procedure to be performed. A standard establishment would be by applying the return path electrode 6 of the patient to the electric waveform generator 1 which is established via the conductive wire of the return path 31. Also included in the standard setting is the connection of the electrosurgical instrument 26 to the electric waveform generator 1 via the electrically conductive insulated cable 25. When the cleaning apparatus 36 includes an assembly as shown in Figure 7, the bearing Cleaning 28 with its electrically conductive metal sheet holder 29 attached and the conductive element 30 are removed from a package (not shown) that maintains sterility during shipping and storage. The conductive element 30 is connected so that there is electrical continuity to the electric return path 31 of the electric waveform generator 1. If the cleaning bearing 28 is not wet yet, then it is moistened with normal saline. The cleaning bearing 28 with its electrically conductive metal sheet holder 29 and any other support and joining device that may be part of the assembly are placed in a convenient location for the surgeon. Attaching it to a cloth near the surgical site would be likely. Cutting and other surgical procedures occur in a conventional manner. When scab is being removed from the work surfaces of the portable instrument 26, such as the metal cutting element 27, they are gently pressed against the cleaning pad 28. The module 27 may be provided to detect contact between the work surfaces and the cleaning bearing 28 and automatically activates the low frequency source 2 to produce the correct electric waveform. The energy for this electrical waveform flows from the source 2 through the electrically conductive insulated wire 25, through the electrosurgical instrument 26, through the metal cutting element 27, and towards the cleaning bearing 28 (which is moistened with normal saline) and its electrically conductive metal foil support 29. Almost immediately (ie, in 1 to 10 seconds) the present eschar loosens and falls off the work surfaces or is easily cleaned from the work surfaces without any apparent effort. With a little delay, and with the work surfaces now clean, the surgeon can continue with the surgical procedure. In the case where the conductive solution is sprayed on the work surfaces, cutting and other surgical procedures occur in the usual manner and the spray mist is directed to the work surfaces. Little, or no eschar forms and adheres to work surfaces when the work surfaces are made of, for example, a copper-based substance. The modalities described above are for illustration purposes only. Numerous modifications and extensions will be apparent to those skilled in the art and are intended to be within the scope of the present invention as contemplated by the claims presented below.

Claims

CLAIMS 1. An electrosurgical method to obtain at least one predetermined surgical effect at a tissue site, comprising: supplying an electrosurgical signal to a work surface of an electrosurgical instrument; providing an electrical signal return path of such a tissue site; and passing electrical energy to the tissue site of said work surface, wherein the work surface has a negative voltage polarization in relation to the return path.
2. An electrosurgical method according to claim 1, said step of supplying includes: combining a first signal component and a second signal component to obtain such an electrosurgical signal.
3. An electrosurgical method according to claim 2, said step of supplying further includes: using a radio frequency electrosurgical generator to generate such a first signal component.
4. An electrosurgical method according to claim 3, said step of supplying further includes: employing said first signal component to obtain said second signal component.
An electrosurgical method according to claim 4, wherein said first signal component has a first frequency and said second signal component has a second frequency, said second frequency is less than said first frequency.
6. An electrosurgical method according to claim 5, wherein said first frequency is greater than about 100 kHz and said second frequency is less than about 10 kHz.
7. An electrosurgical method according to claim 3, said step of supplying further includes: employing a source of electrical energy, separate from said radio frequency electrosurgical generator, to provide said second signal component.
8. An electrosurgical method according to claim 5, further comprising: using at least one first frequency polarized block or component to isolate said electrosurgical generator from said electrical power source; employing at least one second frequency polarized blocking component to isolate said electrical power source from such electrosurgical generator.
An electrosurgical method according to claim 7, wherein said source of electrical energy is selected from the group comprising: a source of direct current energy, and a source of energy that varies in time that has a lower operating frequency than an operating frequency of the radio frequency electrosurgical generator.
10. An electrosurgical method according to claim 4, wherein said second signal component is a direct current signal. 1.
An electrosurgical method according to claim 2, further comprising: cleaning said working surface of such an electrosurgical instrument, wherein said cleaning step includes: applying an electrical cleaning signal, different from said electrosurgical signal , to said work surface.
12. An electrosurgical method according to claim 1, further comprising: contacting said electrosurgical instrument with a conductive liquid; contacting a conductive return electrode with such conductive liquid, wherein a negative voltage polarization is provided in said electrosurgical instrument with respect to such a return electrode.
The method of claim 1, wherein the average bias voltage exceeds about 1 volt.
The method of claim 1, wherein the average bias voltage is between about 1 and 60 volts.
15. The method of claim 1, wherein the work surface comprises stainless steel.
16. The method of claim 1, wherein the work surface comprises at least one material having a standard reduction potential that is positive with respect to a standard hydrogen electrode.
The method of claim 16, wherein the work surface comprises at least one material selected from a group comprising the elements of Group IB of the Periodic Table of Elements.
18. The method of claim 17, wherein the work surface comprises at least one of the group comprising copper, silver and gold.
19. The method of claim 1, further comprising: spraying the work surfaces with a conductive liquid during at least said passing step.
20. An apparatus for use in an electrosurgical system having a delivery path for applying an electrosurgical signal to a patient and a return path of such a patient to complete an electrosurgical circuit, an apparatus comprising: means for providing an electrosurgical component; negative polarization signal; and means for combining such a negative bias signal component with a radio frequency signal component to provide such an electrosurgical signal, wherein such an electrosurgical instrument has a negative mean voltage bias with respect to the return path device. twenty-one .
An apparatus according to claim 20 further comprising: an electrosurgical generator for providing said radio frequency signal component.
22. Apparatus according to claim 21, such means for providing include: a source of electrical energy separate from such electrosurgical generator.
23. An apparatus according to claim 22, wherein said source of electrical energy comprises at least one of a direct current energy source and a time variable energy source.
24. An apparatus according to claim 23, wherein said radio frequency signal component has a first minimum frequency and such a negative bias signal component has a second maximum frequency, such a first frequency is greater than said second frequency. , and wherein said apparatus additionally comprises: at least one of a first frequency polarized blocking component and a derivation component based on the first frequency for isolating said time-variable energy source from said radio frequency signal component; and at least one of a second frequency polarized blocking component and a derivation component based on the second frequency for isolating said electrosurgical generator from said negative bias signal component.
25. An apparatus according to claim 21, wherein said means for providing uses said radio frequency signal component to generate said negative bias signal component.
26. An apparatus according to claim 20, further comprising: a portable electrosurgical instrument defining said supply path and having work surfaces comprising stainless steel.
27. An apparatus according to claim 20, further comprising: a portable electrosurgical instrument which defines said supply path and which has work surfaces comprising at least one material of the group comprising: copper, silver and gold.
28. An apparatus according to claim 20, further comprising: a portable electrosurgical instrument that defines the aforementioned trajectory of its ministrus; and means for applying an electrical signal, separated from said electrosurgical signal, to said electrosurgical instrument during a cleaning procedure.
29. An apparatus according to claim 28, further comprising: a cleaning assembly for receiving such an electrosurgical instrument during said cleaning procedure, comprising: a conductive liquid; and a return electrode in electrical contact with said liquid.
30. A method for cleaning scara of a surgical instrument comprising: applying an electrical signal to said instrument, and contacting said instrument with means for cleaning the instrument during at least a portion of such an application step to remove said eschar.
31 Such a method according to claim 30, wherein said means is electrically conductive, and further comprises: contacting a conductive return electrode with such conductive means during said portion of such an application step, wherein a voltage bias Negative is provided in said instrument in relation to such return electrode.
32. The method of claim 31, wherein said means is a conductive liquid, and the contact step comprises: submerging working surfaces of the instrument in the conductive liquid.
33. The method of claim 32, wherein the conductive liquid is held in a container.
34. The method of claim 33, wherein the container ft 5 comprises contact means for selectively establishing electrical contact between the instrument and the conductive liquid after insertion of the instrument into said container.
35. The method of claim 33, wherein the container 10 includes attachment means for selectively and supportably attaching the container to a support surface.
36. The method of claim 31, wherein said means comprises a conductive liquid held by an absorbent member, and further comprises: cleaning the surfaces against said absorbent member.
37. The method of claim 31, wherein the negative voltage bias is greater than about 10 volts.
38. The method of claim 37, wherein the negative voltage bias is between about 10 and about 120 volts.
39. The method of claim 30, wherein the electrical signal is defined by a substantially direct current.
40. The method of claim 34, wherein the direct current has a bias voltage greater than about 10 volts.
41 A method according to claim 30, further comprising: using an electrosurgical generator to provide such an electrical signal.
42. A method according to claim 41, said step of using includes: rectifying a radio frequency output of such electrosurgical generator.
43. A method according to claim 42, wherein said rectifying step includes: using at least one diode.
44. An apparatus for cleaning eschar of a surgical instrument comprising: means for applying an electrical cleaning signal to such an intrument during a cleaning process; means for receiving the instrument intrude during such a cleaning procedure, including: an electrically conductive means; and an electrically conductive return electrode in contact with said conductive means.
45. An apparatus according to claim 44, wherein said means for applying can be operated to maintain such an instrument at a negative electrical power with respect to the return electrode.
46. An apparatus according to claim 44, wherein said conductive means comprises a conductive field, and said apparatus further comprises: a housing means for retaining said conductive fluid.
47. An apparatus according to claim 44, further comprising: means for automatically activating said means for applying after contact between said instrument and said conductive means.
48. An apparatus according to claim 44, further comprising: an electrosurgical generator for providing a source signal; and means for using such a source signal to provide such electrical cleaning signal.