Abstract:
An electrosurgical device is provided that includes a handset having a shaft extending therefrom, a pair of active electrodes at a distal end of the shaft, and a movable, electrically floating electrode selectively positionable between the active electrodes. The floating electrode, when positioned to contact tissue between the active electrodes, modifies the electrosurgical current flows through tissue. The resultant modified current flows enables a surgeon to more effectively to control tissue desiccation by focusing electrosurgical energy toward targeted tissue and by reducing peripheral current flows. Embodiments are provided wherein the active electrodes include cooling provisions. Related electrosurgical systems and method of use are also provided.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/884,573, filed on Sep. 30, 2013, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to a bipolar electrosurgical instrument configured to provide controlled deep tissue desiccation. More particularly, the present disclosure relates to an electrosurgical instrument that includes a pair of electrodes and a movable floating electrode that enables a surgeon to effectively control tissue desiccation. 
         [0004]    2. Description of Related Art 
         [0005]    Electrosurgical devices, such as surface tissue desiccation devices are well known in the medical arts and typically include a handset with an on/off switch, a shaft, and at least one electrode operatively coupled to a distal end of the shaft that is configured to perform an electrosurgical procedure, such as surface or deep tissue desiccation. Such electrosurgical devices utilize electrical energy to effectuate hemostasis and desiccation by heating the tissue and blood vessels. Such devices include electrocautery pencils, forceps, and probes of various types and configurations from a number of different manufacturers. The algorithms used with these electrosurgical devices in surgical treatments typically seek to provide a desired amount of delivered energy in accordance with the power level and duration specified by the surgeon. 
         [0006]    Electrosurgical devices which utilize this electrical energy for performing deep tissue coagulation and desiccation during orthopedic procedures, such as spinal and joint replacement surgery, may have drawbacks which influence surgical outcomes. For example, a typical issue is the inability of a surgeon to reliably and selectively control tissue treatment depth during desiccation procedures. It has been observed that during desiccation procedures, surgeons tend to manipulate tissue with the electrodes of the device to retract and separate tissue. This technique, however, may extend operative times and/or cause unsatisfactory results due to varying contact area between the electrode and tissue as the instrument is manipulated. 
       SUMMARY 
       [0007]    In view of the foregoing, an electrosurgical instrument that includes a pair of electrodes and a movable floating electrode that enables a surgeon to effectively control tissue desiccation, and associated systems and methods of use, would be a welcome advance in the state of the art. 
         [0008]    Embodiments of the present disclosure are described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. As used herein, the term “distal” refers to the portion that is being described which is further from a user, while the term “proximal” refers to the portion that is being described which is closer to a user. 
         [0009]    As it is used herein, “electrosurgical procedure” generally refers to any electrosurgical procedure involving any form of energy, such as, for example, microwave energy and radiofrequency (RF) energy. 
         [0010]    In one aspect of the present disclosure, an electrosurgical instrument is provided. The electrosurgical instrument includes a handle having a shaft extending distally therefrom, a first active electrode and a second active electrode disposed in spaced relation on a distal end of the shaft, and a floating electrode or electrode selectively positionable between an extended position where the floating electrode is disposed within an area between the first active electrode and a second active electrode, and a retracted position where the floating electrode is removed from the area between the first active electrode and a second active electrode. The first active electrode and a second active electrode may be configured to couple to a source of electrosurgical energy. The first active electrode, the second active electrode, and the floating electrode may each include a tissue-contacting surface. 
         [0011]    In some embodiments, when the floating electrode is in the extended position, the tissue-contacting surfaces of the first active electrode, the second active electrode, and the floating electrode lie substantially in the same plane. The active electrodes may be configured to operate in a bipolar mode of operation. 
         [0012]    In other embodiments, the electrosurgical instrument includes a coolant supply conduit configured to deliver coolant to the first active electrode and the second active electrode, and a coolant return conduit configured to remove coolant from the first active electrode and the second active electrode. In yet other embodiments, the first and second active electrodes are each in thermal communication with a heat pipe that is configured to draw heat from the first and second active electrodes to the ambient atmosphere. 
         [0013]    The electrosurgical instrument may include a drive mechanism having a drive member movable along a longitudinal axis of the shaft between a first position and a second position, a cam slot defined in a distal end of the drive member, and a follower fixed to the floating electrode and configured to operably engage the cam slot. When the drive member is in a first position the floating electrode is in the extended position, and wherein when the drive member is in a second position, the floating electrode is in the retracted position. 
         [0014]    In an alternative embodiment, the drive mechanism may include a drive member movable along a longitudinal axis of the shaft between a first position and a second position and an electrode guide. The electrode guide may include an elongated entrance opening defined at an entrance end of the electrode guide having an entrance direction and an elongated exit opening defined at an exit end of the electrode guide and having an exit direction different from the entrance direction. The electrode guide may include a channel joining the entrance opening and the exit opening and include an elbow transitioning the channel from the entrance direction to the exit direction. The cross section of the channel at the elbow may have an elongated rectangular shape, and the cross section of the channel at the exit opening may have a curved elongated rectangular shape. The floating electrode may be formed from a strip of flexible material positioned, in part, within the electrode guide, and operably coupled to a distal end of the drive member. 
         [0015]    In another aspect of the present disclosure, an electrosurgical system is provided. The disclosed electrosurgical system includes an electrosurgical generator and an electrosurgical instrument as described above. The electrosurgical generator and the pair of electrodes may be configured to operate in a bipolar mode of operation. 
         [0016]    In yet another aspect of the present disclosure, a method for electrosurgically treating tissue is provided. The disclosed method includes the steps of providing an electrosurgical device as described above, applying the first active electrode and the second active electrode to tissue, and delivering electrosurgical energy to tissue via the first active electrode and the second active electrode. The method may include the steps of applying the floating electrode to tissue and/or removing the floating electrode from tissue. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Various embodiments of the present disclosure are described hereinbelow with references to the drawings, wherein: 
           [0018]      FIG. 1  is a perspective view of a system for electrosurgically treating tissue according to an embodiment of the present disclosure; 
           [0019]      FIG. 2A  is a schematic view of bipolar electrodes and a floating electrode in a raised configuration in accordance with an embodiment of the present disclosure; 
           [0020]      FIG. 2B  is a schematic view of bipolar electrodes and a floating electrode in a lowered configuration in accordance with an embodiment of the present disclosure; 
           [0021]      FIG. 2C  is a schematic view of bipolar electrodes and a bifurcated electrode having a fixed potential in a lowered configuration in accordance with another embodiment of the present disclosure; 
           [0022]      FIG. 2D  is a schematic view of bipolar electrodes and a bifurcated electrode having a variable potential in a lowered configuration in accordance with yet another embodiment of the present disclosure; 
           [0023]      FIG. 3  is a view of an electrosurgical instrument in accordance with an embodiment of the present disclosure having a circulating coolant system; 
           [0024]      FIG. 4  is a view of an electrosurgical instrument in accordance with an embodiment of the present disclosure having a heat pipe coolant system; 
           [0025]      FIG. 5A  is a detail, side view of a floating electrode and a drive member of an electrosurgical instrument in accordance with an embodiment of the present disclosure; 
           [0026]      FIG. 5B  is a detail, perspective view of a floating electrode and a drive member of the  FIG. 5A  embodiment; 
           [0027]      FIG. 5C  is an end view of a drive member of a floating electrode and a drive member of the  FIG. 5A  embodiment; 
           [0028]      FIG. 6A  is a detail, side view of a floating electrode and a drive member of an electrosurgical instrument in accordance with another embodiment of the present disclosure; 
           [0029]      FIG. 6B  is a detail, perspective view of a floating electrode and a drive member of the  FIG. 6A  embodiment; 
           [0030]      FIG. 7A  is a side view of a deployable floating electrode in a raised position in accordance with yet another embodiment of the present disclosure; 
           [0031]      FIG. 7B  is a side view of a deployable floating electrode in a lowered position in accordance with the  FIG. 7A  embodiment; 
           [0032]      FIG. 7C  is a top view of a floating electrode guide in accordance with the  FIG. 7A  embodiment; 
           [0033]      FIG. 7D  is a bottom view of a floating electrode guide in accordance with the  FIG. 7A  embodiment; 
           [0034]      FIG. 7E  is a perspective view of a floating electrode and guide in accordance with the  FIG. 7A  embodiment; 
           [0035]      FIG. 7F  is a section view of a floating electrode guide in accordance with the  FIG. 7A  embodiment; and 
           [0036]      FIG. 7G  is another section view of the floating electrode guide in accordance with the  FIG. 7A  embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0037]    Particular embodiments of the present disclosure are described hereinbelow with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. In this description, as well as in the drawings, like-referenced numbers represent elements which may perform the same, similar, or equivalent functions; the term “proximal,” as is traditional, shall refer to the end of the instrument that is closer to the user, while the term “distal” shall refer to the end that is farther from the user. In addition, references to positive (+) and negative (−) are for illustrative purposes only, and it is to be understood that the polarity of the described elements may vary over time in accordance with the alternating current nature of electrosurgical energy. 
         [0038]    Referring to  FIG. 1 , there is shown a perspective view of an electrosurgical system  1  including a generator  5  having a controller  7 , and an electrosurgical instrument  10  for electrosurgically treating tissue according to an embodiment of the present disclosure. A coolant unit  27  is provided for delivering fluid to electrodes  12 ,  14  of electrosurgical instrument  10 . Cooling unit  27  includes a coolant reservoir  28  in which a supply of coolant may be maintained, such as, without limitation, deionized water, glycol, saline, and the like. Cooling unit  27  may include a coolant pump  25  that is configured to circulate coolant between reservoir  28  and instrument  10  via coolant supply conduit  26  and coolant return conduit  24 . Coolant supply conduit  26  and coolant return conduit  24  are electrically isolated from one other. In some embodiments, the cooling fluid circulated through coolant supply conduit  26  and coolant return conduit  24  is a non-conducting or a low conductive substance. 
         [0039]    Continuing with reference to  FIG. 1 , generator  5  is configured to generate and deliver electrosurgical energy, e.g., radio frequency energy, to active electrodes  12  and  14 , for performing electrosurgical procedures. The electrosurgical procedures may include cutting, cauterizing, coagulating, desiccating, and fulgurating tissue; all of which may employ RF energy. Generator  5  may be configured for monopolar and/or bipolar modes of operation. For illustrative purposes, generator  5  and, hence, system  1 , is shown configured for a bipolar mode of operation. 
         [0040]    Generator  5  includes one or more processors  8  that are in operative communication with controller  7  and configured to transmit electrosurgical energy, which may be in the form of a wave or signal/pulse, via cable  6  to instrument  10 . Controller  7  and/or processor  8  may include one or more control algorithms that regulate the delivery of electrosurgical energy to tissue in accordance with an impedance of an electrode-tissue interface. One or more data lookup tables accessible by controller  7  and/or processor  8  may utilized to store relevant information relating to impedance and/or energy delivery. This information relating to impedance and/or pressure may be acquired empirically and/or calculated utilizing one or more suitable equations. 
         [0041]    In the embodiment illustrated in  FIG. 1 , instrument  10  is shown as a bipolar electrocautery pencil (such as the one described in commonly-owned U.S. Pat. No. 7,621,909 to Buchman II, et al.) that includes a proximal handle  15  and a distal shaft  16 . Handle  15  includes a slide actuator  19  that is configured to selectively position a movable, electrically floating electrode  11  between active electrode  12  and active electrode  14 . Floating electrode  11  is formed from conductive material, and may be lowered (extended) and raised (retracted) between electrodes  12  and  14  to alter the energy field formed therebetween during electrosurgical procedures. In the embodiment illustrated in  FIG. 1 , moving slide actuator  19  distally causes floating electrode  11  to lower between electrodes  12  and  14 . Conversely, moving slide actuator  19  proximally retracts floating electrode  11 . In other embodiments, floating electrode  11  may be lowered by moving slide actuator  19  proximally and raised by moving slide actuator  19  distally. In yet other embodiments, a trigger actuator, a rotary actuator, or motorized actuator may be employed to extend and retract floating electrode  11 . 
         [0042]    Shaft  16  extends distally from handle  15 , and active electrode  12  and active electrode  14  are disposed at a distal end  17  of shaft  16 . In some embodiments, a guide  18  is operatively associated with floating electrode  11  to facilitate the selective positioning thereof. 
         [0043]    In some embodiments, instrument  10  may be configured for a monopolar mode of operation. In these embodiments, one or both of the active electrodes  12  or  14  is configured to deliver monopolar electrosurgical energy to tissue, and a return pad (not explicitly shown) may be positioned on a patient and utilized as a return electrode. 
         [0044]    Advantageously, use of the movable floating electrode  11  in accordance with the present disclosure enables a surgeon to selectively control the intensity and/or depth of the electrosurgical effect from the adjacent electrodes  12 ,  14 . This advantage is illustrated in detail with reference to  FIGS. 2A and 2B . As shown in  FIG. 2A , an electrode assembly  30  includes a first electrode  32  and a second electrode  34  positioned in a fixed, spaced relation to one another and coupled to a source of electrosurgical energy  35  by conductors  36 , and a movable, floating electrode  31  selectively positioned in a raised position. The electrodes  32 ,  34  are brought into contact with tissue T at the targeted area, and the source of electrosurgical energy  35  is activated. Electrosurgical energy flows between electrodes  32 ,  34  forming a radiating pattern  37  which radiates between electrodes  32 ,  34 . As seen in  FIG. 2A , radiating pattern  37  forms not only a relatively direct path directly between electrodes  32 ,  34 , but also radiates away from electrodes  32 ,  34 , which may cause undesired tissue effects peripheral to the targeted tissue area. 
         [0045]    Turning to  FIG. 2B , where floating electrode  31  is shown in a lowered position in contact with tissue T, a modified radiating pattern  38  is formed when electrosurgical energy is delivered by electrodes  32 ,  34 . As can be seen in  FIG. 2B , the modified radiating pattern  38  converges at floating electrode  31  to focus more precisely to the targeted tissue site. In addition, peripheral radiation is decreased. It is believed that the floating electrical potential of floating electrode  31 , when positioned between electrodes  32 ,  34 , is determined by the impedance(s) if the tissue T between the electrodes  32 ,  34  and the electrosurgical current lowing therebetween. Thus the potential of floating electrode  31  falls between the voltages of electrodes  32 ,  34 , which, in turn, creates the modified radiating pattern  38  as illustrated in  FIG. 2B . 
         [0046]    Advantageously, a surgeon may utilize floating electrode  31  as an additional tool surface with which to dissect tissue T. For example, a surgeon may extend or lower floating electrode  31  and manipulate the entire instrument, bringing electrodes  32 ,  34  and floating electrode  31  into, and out of, contact with tissue T to work the surgical site. In another example, a surgeon may bring electrodes  32 ,  34  into substantially continuous contact with tissue T, and manipulate floating electrode  31  up and down using an actuator (e.g., finger trigger or slide as described herein). In yet another example, a surgeon may variously utilize combinations of the above techniques, compound motions, and the like, as required by the instant surgical objective. 
         [0047]    In another aspect of the present disclosure illustrated in  FIG. 2C , an electrosurgical instrument  130  includes a movable active electrode  131  that is selectively positionable between fixed active electrodes  132 ,  134 . Active electrode  131  includes two conductive sections  141  and  142  that are electrically isolated by an insulator  143  disposed therebetween. An electrosurgical generator  135  is coupled to electrodes  132 ,  134  by conductors  136 ,  137 , respectively. Conductive sections  141  and  142  are electrically coupled to fixed active electrodes  132 ,  134  by conductors  146 ,  147 , respectively. By this arrangement, negative movable active electrode  142  is positionable adjacent to positive fixed active electrode  132 , and negative movable active electrode  141  is positionable adjacent to positive fixed active electrode  134 . Advantageously, the alternating polarity arrangement of the  FIG. 2C  electrodes enhances the focus of modified radiating pattern  138 , which effectively creates a dual bipolar ablation zone. 
         [0048]    In yet another aspect of the present disclosure illustrated in  FIG. 2D , an electrosurgical instrument  230  includes a movable active electrode  231  that is selectively positionable between fixed active electrodes  232 ,  234 . Active electrode  231  includes two conductive sections  241  and  242  that are electrically isolated by an insulator  243  disposed therebetween. An electrosurgical generator  235  is coupled to electrodes  232 ,  234  by conductors  236 ,  237 , respectively. Conductive sections  241  and  242  are electrically coupled to a dual-channel intensity control  250  by conductors  244 ,  248 , respectively. Electrosurgical generator  235  is coupled to intensity control  250  by conductors  240  and  247 . Intensity control  250  may be continuously variable, and may be user controlled by, e.g., a user interface control such as rotary control (knob) or a linear control (slider or lever). In some embodiments, intensity control  250  may be controlled by a processor and/or in accordance with a tissue parameter, such as, without limitation, tissue temperature, tissue impedance, ablation time, tissue hydration, and/or a rate of change of the same. In some embodiments, intensity control  250  may have an effective range of 0% to 100% of the electrosurgical signal generated by generator  235 . In other embodiments, intensity control  250  may have an effective range of −100% to 100% of the electrosurgical signal generated by generator  235 . In yet other embodiments, intensity control  250  may have an effective range of 0% to greater than 100% or +/−100% of the electrosurgical signal (e.g., imparting gain to the electrosurgical signal). 
         [0049]    In another aspect of the present disclosure illustrated in  FIG. 3 , an electrosurgical instrument  40  includes a coolant supply conduit  47  configured to deliver coolant to first electrode  42 , and to second electrode  44 . Electrodes  42 ,  44  are coupled to a source of electrosurgical energy  45  by conductors  46 . As shown, electrodes  42  and  44  each include a cooling chamber  55  and  56 , respectively, defined therein. Coolant supply conduit  47  is coupled at a distal end thereof to cooling chamber  55  to deliver coolant thereto. An intermediate outflow conduit  50  having a distal opening  53  disposed within cooling chamber  55  is configured to receive coolant exiting from cooling chamber  55 . Coolant flows through intermediate outflow conduit  50  to a coupler  51  which is configured to join intermediate outflow conduit  50  and intermediate inflow conduit  52  in fluid communication. In some embodiments, such as that illustrated in  FIG. 3 , coupler  51  is u-shaped. In some embodiments, coupler  51  is formed from electrically and/or thermally insulative material. Intermediate inflow conduit  52  receives coolant from intermediate outflow conduit  50  via coupler  51 , and, in turn, delivers coolant to second electrode  44  via opening  54  disposed within cooling chamber  56 . Coolant return conduit  48  is in fluid communication with cooling chamber  56  of electrode  44  to receive coolant exiting from cooling chamber  56  and, in turn, exhausts coolant from instrument  40  to a reservoir, drain, etc. 
         [0050]    In other embodiments, the coolant supply may be arranged in a parallel configuration whereby incoming coolant is divided (using, e.g., a “Y” coupling or a manifold) and directed to each electrode, and outgoing coolant from each electrode is joined at a combining junction and exits instrument  40  via coolant return conduit  48 . 
         [0051]    Instrument  40  includes a floating electrode  41  that is selectively extendible between electrode  42  and electrode  44 . A follower  58  is joined to an upper portion of floating electrode  41  that is configured to ride within a cam slot  57  defined in a distal end of a drive member  43 . Drive member  43  is configured to move longitudinally, e.g., distally and proximally, and includes a trigger  49  that facilitates manipulation of drive member  43  by a surgeon. As shown in the  FIG. 3  embodiment, a distal movement of drive member  43  causes follower  58  to ride downward within cam slot  57 , thereby moving floating electrode  41  into an extended, lowered, or deployed, position. Conversely, proximal movement of drive member  43  causes floating electrode  41  to move to a retracted or raised position. Instrument  40  may include ergonomic features, such as, without limitation, a handle (not explicitly shown), a pistol grip (not explicitly shown) or any other suitable features configured to facilitate grasping and use by a surgeon. 
         [0052]    In another aspect of the present disclosure, an embodiment of an electrosurgical instrument  60  is shown in  FIG. 4  which includes a first electrode  62  and a second electrode  64  disposed in electrical communication with an electrosurgical generator  65  via conductors  66 . A movable floating electrode  61  includes a follower  78  that is configured to engage a cam slot  71  defined in a proximal portion of a drive member  63 . Drive member  63  is configured to move distally and proximally, which translates into an up-and-down motion of floating electrode  61  through the cooperation of follower  78  and cam slot  71 . Drive member  63  includes a trigger  69  or similar ergonomic feature to facilitate the actuation thereof by a surgeon. Instrument  60  may include ergonomic features, such as, without limitation, a handle  79  or any other suitable features intended to facilitate handling. 
         [0053]    Instrument  60  includes a first heat pipe  67  having a hot end  73  that is in thermal communication with electrode  62  and a cool end  75 , and a second heat pipe  68  having a hot end  74  that is in thermal communication with electrode  64  and a cool end  76 . Heat pipes  67  and  68  may include a heat pipe construction which includes a sealed copper pipe having contained therein a quantity of fluid, such as water or ethanol, and/or a partial vacuum that is near or below the vapor pressure of the fluid. During use, some of the fluid will be in liquid phase and some will be in gas phase. As the hot ends  73 ,  74  of heat pipes  67 ,  68  are heated due to thermal effects relating to an electrosurgical procedure, the fluid inside heat pipes  67 ,  68  vaporizes and increases the vapor pressure therein. The latent heat of evaporation absorbed by the vaporization of the working fluid reduces the temperature at the hot ends  73 ,  74  of heat pipes  67 ,  68 . The vapors migrate to the respective cool ends  75 ,  76  of heat pipes  67 ,  68  where they condense and revert to liquid phase, releasing the absorbed heat. A wick  72 ,  77  disposed, respectively, within an inner surface of heat pipes  67 ,  68 , absorbs any liquid by capillary action and returns the liquid to the hot ends  73 ,  74  of heat pipes  67 ,  68  in an essentially continuous cycle. In some embodiments, cool ends  75 ,  76  of heat pipes  67 ,  68  are exposed to the ambient atmosphere, and may include one or more heat sinks (not shown) to facilitate the heat transfer cycle. 
         [0054]    Turning to  FIGS. 5A-5C , a detailed view of a drive mechanism  80  in accordance with the present disclosure is presented. Drive mechanism  80  is arranged such that a distal motion of an actuation ring  89  results a downward motion of the floating electrode  81 . Drive mechanism  80  includes a drive member  83  having a cam slot  87  defined therein at a distal end thereof. As best seen in  FIG. 5A , cam slot  87  is angled with respect to the longitudinal axis “A-A” of drive member  83  and has a distal end that is higher than the proximal end. The floating electrode  81  includes a follower  88  joined to an upper portion of the floating electrode  81  by an extension  86 . In some embodiments, floating electrode  81 , extension  86 , and follower  88  may be integrally formed from sheet metal using a punching and/or stamping process. In some embodiments, floating electrode  81 , extension  86 , and follower  88  may be formed from stainless steel. Follower  88  is disposed at an angle with respect to floating electrode  81  which substantially corresponds to the angle of cam slot  87 . In the  FIGS. 5A-5C  embodiments, where forward (distal) motion of the drive member  83  causes downward deployment of floating electrode  81 , an actuation ring  89  may be provided to enable a surgeon to readily manipulate drive member  83  in either a distal or proximal direction. 
         [0055]    In another embodiment depicted in  FIGS. 6A and 6B , a drive mechanism  90  in accordance with the present disclosure is arranged such that proximal motion of an actuation trigger  99  results a downward motion of the floating electrode  91 . Drive mechanism  90  includes a drive member  93  having a cam slot  97  defined therein at a distal end thereof. Here, cam slot  97  is angled with respect to the longitudinal axis “B-B” of drive member  93  such that the distal end of cam slot  97  is lower than the proximal end of cam slot  97 . Floating electrode  91  includes a follower  98  joined to an upper portion of the floating electrode  91  by an extension  96 . Follower  98  is disposed at an angle which substantially corresponds to the angle of cam slot  97 . Rearward (proximal) motion of drive member  93  causes downward deployment of floating electrode  91 . In this embodiment, trigger  99  is provided to enable the surgeon to intuitively manipulate drive member  93  in proximal direction to deploy floating electrode  91 . A return spring  95  is provided which biases drive member  93  in a distal direction, thus when a surgeon releases pressure on trigger  99 , drive member  93  is driven distally and floating electrode  91  is moved upwardly through the cooperation of follower  98  and cam slot  97 . 
         [0056]    Turning now to  FIGS. 7A-7G , yet another embodiment of a drive mechanism  100  for a floating electrode  101  is presented. Floating electrode  101  is formed from a strip of flexible material, such as spring steel, Nitinol (or other shape memory metal), and/or a high-temperature-resistant composite material. A proximal end of floating electrode  101  is joined to a drive member  103  by a pin  102 . Drive member  103  includes a thumb actuator  109  which is configured to be manipulated a surgeon to effectively lower and raise floating electrode  101 . A distal portion of floating electrode  101  passes through an L-shaped electrode guide  108  having a channel  107  defined therein. Channel  107  includes an entrance  105  into which floating electrode  101  is introduced and an exit  106  through which floating electrode  101  extends toward tissue. 
         [0057]    Electrode guide  108  includes a 90° transition elbow having a radius a which enables the distal portion of floating electrode  101 , as it is advanced distally by drive member, to bend downwardly and thus extend into a lowered position between the bipolar electrodes (not explicitly shown). As can be seen in  FIG. 7F , a cross section of channel  107  adjacent to radius a is substantially straight, enabling the flexible floating electrode  101  to remain flat and thus allowing floating electrode  101  to flex easily as it is advanced through radius a during deployment of floating electrode  101  into position between electrodes. As channel  107  approaches exit  106 , the cross section of channel  107  become slightly curved as shown in  FIGS. 7E and 7G . As flexible floating electrode  101  extends from exit  106 , this curve is imparted to floating electrode  101  ( FIG. 7E ), which, in turn, provides rigidity and stiffness to the extended portion  110  of floating electrode  101 . 
         [0058]    In some embodiments, the inner surface of channel  107  and/or the outer surface of flexible floating electrode  101  may include a lubricious coating, such as, without limitation, polytetrafluoroethylene (PTFE). 
         [0059]    The various embodiments disclosed herein may also be configured to work with robotic surgical systems and what is commonly referred to as “Telesurgery”. Such systems employ various robotic elements to assist the surgeon in the operating theatre and allow remote operation (or partial remote operation) of surgical instrumentation. Various robotic arms, gears, cams, pulleys, electric and mechanical motors, etc. may be employed for this purpose and may be designed with a robotic surgical system to assist the surgeon during the course of an operation or treatment. Such robotic systems may include remotely activatable active electrodes, a remotely positionable floating electrode, remotely steerable systems, remotely articulating surgical systems, wireless surgical systems, modular, or selectively configurable remotely operated surgical systems, etc. 
         [0060]    The robotic surgical systems may be employed with one or more consoles that are next to the operating theater or located in a remote location. In this instance, one team of surgeons or nurses may prep the patient for surgery and configure the robotic surgical system with one or more of the instruments disclosed herein while another surgeon (or group of surgeons) remotely control the instruments via the robotic surgical system. As can be appreciated, a highly skilled surgeon may perform multiple operations in multiple locations without leaving his/her remote console which can be both economically advantageous and a benefit to the patient or a series of patients. 
         [0061]    The robotic arms of the surgical system are typically coupled to a pair of master handles by a controller. The handles can be moved by the surgeon to produce a corresponding movement of the working ends of any type of surgical instrument (e.g., end effectors, graspers, knifes, scissors, etc.) which may complement the use of one or more of the embodiments described herein. The movement of the master handles may be scaled so that the working ends have a corresponding movement that is different, smaller or larger, than the movement performed by the operating hands of the surgeon. The scale factor or gearing ratio may be adjustable so that the operator can control the resolution of the working ends of the surgical instrument(s). 
         [0062]    The master handles may include various sensors to provide feedback to the surgeon relating to various tissue parameters or conditions, e.g., tissue resistance due to manipulation, cutting or otherwise treating, pressure by the instrument onto the tissue, tissue temperature, tissue impedance, etc. As can be appreciated, such sensors provide the surgeon with enhanced tactile feedback simulating actual operating conditions. The master handles may also include a variety of different actuators for delicate tissue manipulation or treatment further enhancing the surgeon&#39;s ability to mimic actual operating conditions, such as contacting the active electrode to targeted tissue, extending and/or retracting the floating electrode, controlling the delivery of electrosurgical energy, and so forth. 
         [0063]    While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.