Abstract:
An electrode assembly is provided. The electrode assembly includes a proximal end that is adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source. A distal end includes a cutting electrode having a loop configuration configured to cut tissue. The distal end includes a return electrode operably disposed adjacent the cutting electrode. A dielectric shield is operably disposed between the cutting electrode and return electrode. The dielectric shield extending distally past the cutting electrode to hinder current flow to the return electrode when the dielectric shield, cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/766,483 filed by Ward on Feb. 19, 2013, the entire contents of which hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to electrosurgical electrodes and, more particularly, to electrosurgical electrodes that provide concentrated amounts of electrosurgical energy to tissue during an electrosurgical procedure. 
         [0004]    2. Background of Related Art 
         [0005]    Currently, there are several surgical therapies utilized for treating benign prostate hyperplasia (BPH). At present, transurethral resection of the prostate (TURP) is predominant in the surgical therapy of BPH. Various alternative treatment devices, e.g., electrovaporization, needle ablation, laser, ultrasound, or microwave therapy have recently become available for treating BPH. However, for efficacy, TURP is still regarded as the reference standard by most clinicians, e.g., urologists. 
         [0006]    In some instances, monopolar electrocautery systems in which current passes through a patient&#39;s body from an active electrode associated with a resectoscope and back to a return electrode that is typically placed on a patient&#39;s leg is utilized during TURP. Disadvantages associated with monopolar electrocautery systems when employed in the treatment of BPH include collateral damage to adjacent tissue (e.g., heating of tissue that is deeper than tissue being treated), unwanted stimulation of the nervous and/or muscle system, and/or possible malfunction of therapeutic devices in operative contact with a patient (e.g., a pacemaker). Another disadvantage associated with monopolar electrocautery systems when employed in the treatment of BPH may include the absorption of hypoosmolar irrigation fluid by a patient (commonly referred to in the art as TUR or TURP syndrome), which is typically a result of extended TURP procedures. 
         [0007]    In view of the aforementioned disadvantages associated with monopolar electrocautery systems for treating BPH, bipolar electrocautery systems including a resectoscope with an active, e.g., cutting electrode, and one or more return electrodes placed on the same axis on the resectoscope have become increasingly popular in the treatment of BPH. More particularly, bipolar electrocautery systems typically provide high current densities to target tissue sites such that the aforementioned negative effects typically associated with the monopolar electrocautery systems are reduced and/or prevented. Moreover, bipolar electrocautery systems utilized for treating BPH typically use one or more types of physiological irrigation fluids, e.g., a solution of sodium chloride, such that the risk of TUR syndrome is reduced and/or eliminated. 
         [0008]    While bipolar electrocautery systems utilized for treating BPH alleviate some, if not all, of the disadvantages associated with monopolar electrocautery systems for treating BPH, there still exists some practical challenges with bipolar electrocautery systems to treat BPH. More particularly, the prostate is a highly vascular organ which bleeds during a resection procedure, e.g., TURP that utilizes either monopolar or bipolar electrocautery systems. Bleeding causes a decrease in visual clarity which, in turn, may lead to a variety of intraoperative difficulties with undesirable consequences, e.g., increased convalescence. In order to minimize bleeding (i.e., increase hemostatic efficacy to the target tissue resection site) electrosurgical energy, i.e., current density, may be maximized at the target tissue resection site. However, when the active electrode is positioned in a conductive medium (e.g., a conductive fluid such as saline) a significant fraction of the applied current passes through the saline to the return electrode(s) and not to the target tissue resection site. This fraction of applied current passing through the saline to the return electrode(s) results in decreased hemostatic efficacy at the target tissue resection site. The amount of current passing through the saline to the return electrode(s) is indirectly proportional to the amount of current passing through the target tissue resection site and, thus, indirectly proportional to the hemostatic efficacy at the target tissue resection site. Moreover, this fraction of the current passing through the saline to the return electrode(s) results in TURP procedures having high power output requirements (due to the reduction of a tissue current density, which, in turn, results in overall applied power being increased to the active electrode). 
         [0009]    In view thereof, electrosurgical electrode efficiency (i.e., improved transfer of current from the active or cutting electrode to the tissue resection site) would improve hemostatic efficacy at the tissue resection site during TURP and reduce the applied power requirements of a power source associated with the resection device and/or active electrode. 
       SUMMARY 
       [0010]    An aspect of the present disclosure provides an electrode assembly. The electrode assembly includes a proximal end that is adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source. A distal end includes a cutting electrode having a loop configuration configured to cut tissue. The distal end includes a return electrode operably disposed adjacent the cutting electrode. A dielectric shield is operably disposed between the cutting electrode and return electrode. The dielectric shield extending distally past the cutting electrode to hinder current flow to the return electrode when the dielectric shield, cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode. 
         [0011]    The dielectric shield may be disposed parallel to the longitudinal axis defined by the housing and above the cutting electrode. The dielectric shield may include a generally arcuate configuration and extend laterally across the electrode assembly. Moreover, the dielectric shield may be formed from flouropolymer, polyimide, polyamide, polyaryl sulfone and silicone plastic. Further, a thickness of dielectric shield may be in the range from about 0.005 inches to 0.100 inches. 
         [0012]    The cutting electrode may be a wire, which may be formed from a metal such as tungsten, tungsten alloys and stainless steel. A cross section of the cutting electrode may include a shape such as circular, hemicircular, square, rectangular, triangular, polygonal and combinations of the above. A cross-section diameter of the wire may range from about 0.25 mm to about 4 mm. The loop configuration of the cutting electrode may include a diameter that ranges from about 3 mm to about 10 mm. 
         [0013]    An aspect of the present disclosure provides an electrosurgical instrument. The electrosurgical instrument includes an elongated housing having a lumen defining a longitudinal axis therethrough. The electrosurgical instrument having distal and proximal ends. The proximal end adapted to connect to electrosurgical energy source. An electrode assembly includes a proximal end adapted to connect to the distal end of the elongated housing and a distal end including a cutting electrode having a loop configuration configured to cut tissue. The distal end including a return electrode operably disposed adjacent the cutting electrode. A dielectric shield is operably disposed between the cutting electrode and return electrode. The dielectric shield extending distally past the cutting electrode to hinder current flow to the return electrode when the dielectric shield, cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode. 
         [0014]    An aspect of the present disclosure provides an electrode assembly. The electrode assembly includes a proximal end that is adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source. A distal end includes a cutting electrode having a loop configuration configured to cut tissue. The distal end includes a return electrode operably disposed adjacent the cutting electrode. An insulative material is operably disposed between the cutting electrode and return electrode to hinder current flow to the return electrode when the insulative material, cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode. 
         [0015]    The insulative material may be disposed parallel to the longitudinal axis defined by the housing and above the cutting electrode. A proximal end of the cutting electrode may include a pair of curved sections. The insulative material may be operably disposed along the pair of curved sections of the cutting electrode. The insulative material may be a flouropolymer, polyimide, polyamide, polyaryl sulfone, silicone plastic and polytetrafluoroethylene. 
         [0016]    An aspect of the present disclosure provides an electrode assembly adapted to connect to an electrosurgical instrument. A proximal end of the electrode assembly is adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source. A distal end of the electrode assembly includes a cutting electrode having a loop configuration configured to cut tissue. The loop configuration of the cutting electrode has a non-uniform cross-section diameter. The distal end includes a return electrode that is operably disposed adjacent the cutting electrode. The non-uniform cross-section diameter of the cutting electrode hinders current flow to the return electrode when the cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode. 
         [0017]    A top portion of the loop configuration of the cutting electrode may include a thicker diameter than a bottom portion of the loop configuration of the cutting electrode such that when the cutting electrode is energized current density adjacent the bottom portion and surrounding tissue is greater than current density at the top portion. 
         [0018]    Yet another aspect of the present disclosure provides an electrosurgical instrument. The electrosurgical instrument includes an elongated sheath including a sheath lumen, a distal end and a proximal end. An electrode assembly includes a proximal end adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source. A distal end includes a cutting electrode having a loop configuration configured to cut tissue. The loop configuration of the cutting electrode has a non-uniform cross-section diameter. The distal end includes a return electrode that is operably disposed adjacent the cutting electrode. The non-uniform cross-section diameter of the cutting electrode hinders current flow to the return electrode when the cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode. 
         [0019]    Another aspect of the present disclosure provides an electrode assembly adapted to connect to an electrosurgical instrument. A proximal end of the electrode assembly is adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source. A distal end of the electrode assembly includes a cutting electrode having a loop configuration configured to cut tissue. The loop configuration of the cutting electrode having a surface finish minimizing the energy required for bubble nucleation on the cutting electrode and promoting vapor bubble adhesion. The surface finish may include a pitted finish or a hydrophobic finish. The distal end including a return electrode that is operably disposed adjacent the cutting electrode. The surface finish of the cutting electrode hinders current flow to the return electrode when the cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode. 
         [0020]    Another aspect of the present disclosure provides an electrode assembly adapted to connect to an electrosurgical instrument. A proximal end of the electrode assembly is adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source. A distal end of the electrode assembly including a cutting electrode having a loop configuration configured to cut tissue. The distal end including a return electrode that is operably disposed adjacent the cutting electrode at a distance maximizing energy per volume and minimizing heating depth such that hemostasis is maximized at a target tissue site. The distance may be in the range from about 3 mm to about 10 mm. The distal end including a return electrode operably disposed adjacent the cutting electrode. The distance between the return electrode and the cutting electrode hinders current flow to the return electrode when the cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode. 
         [0021]    The cutting electrode and return electrode may be in fixed spaced-apart relation with respect to one another. The cutting electrode and return electrode may be in a selectably movable spaced-apart relation with respect to one another such that a variable tissue effect is achieved at the target tissue site. The return electrode may include two return electrodes operably disposed on a respective longitudinal section associated with the electrode assembly. The two return electrodes maybe slidably and axially movable with respect to each other and the cutting electrode. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    Various embodiments of the present disclosure are described hereinbelow with references to the drawings, wherein: 
           [0023]      FIG. 1 . is a schematic plan view of a power supply configured for use with a resectoscope intended for use with an electrode assembly in accordance with the present disclosure; 
           [0024]      FIG. 2  is an enlarged view of the area of detail illustrated in  FIG. 1 ; 
           [0025]      FIG. 3A  is a side, perspective view of an electrode assembly in accordance with an alternate embodiment of the present disclosure; 
           [0026]      FIG. 3B  is a partial, side view of the electrode assembly depicted in  FIG. 3A ; 
           [0027]      FIG. 4A  is a side, perspective view of an electrode assembly in accordance with an alternate embodiment of the present disclosure; 
           [0028]      FIG. 4B  is a graphical representation of a relationship between heating depth and energy per volume versus distance from a return electrode to an active electrode; 
           [0029]      FIG. 4C  is a side, perspective view of an electrode assembly in accordance with an alternate embodiment of the electrode assembly depicted in  FIG. 4A ; 
           [0030]      FIG. 5  is a side, perspective view of an electrode assembly in accordance with an alternate embodiment of the present disclosure; and 
           [0031]      FIG. 6  is a side, perspective view of an electrode assembly in accordance with an alternate embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    Particular embodiments of the presently disclosed electrosurgical electrode 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 that portion of the electrosurgical electrode which is further from the user or surgeon while the term “proximal” refers to that portion of the electrosurgical electrode which is closer to the user or surgeon. 
         [0033]      FIG. 1  sets forth a side, perspective view of an electrosurgical system  10  including an electrosurgical instrument  20  intended for use with an electrosurgical electrode assembly  100  constructed in accordance with one embodiment of the present disclosure. In the embodiment illustrated in  FIG. 1 , the electrosurgical instrument is a resectoscope  20 . The resectoscope  20  may be any suitable type of resectoscope and may be operated in bipolar or monopolar modes. While the following description will be directed towards a resectoscope, it is envisioned that the features and concepts (or portions thereof) of the present disclosure can be applied to any electrosurgical type instrument, e.g., forceps, suction coagulators, wands, etc. 
         [0034]    To facilitate understanding of the electrode assembly  100 , a description of the resectoscope  20  illustrated in  FIG. 1  now follows. Briefly, resectoscope  20  includes an elongated sheath or housing  22  with a sheath lumen extending substantially along the entire length of sheath  22 . A support frame connects electrosurgical electrode assembly  100  to one or more suitable types of electrosurgical energy sources, e.g., electrosurgical generator “G.” The support frame provides structural support for the electrode assembly  100  and/or one or more operative components associated with the resectoscope  20 . To this end, support frame may be made of stainless or corrosion resistant material, and the like. Resectoscope  20  includes a working element  24  that is attached to sheath  22 . Working element  24  of resectoscope  20  may include a stationary handle  28 , a movable handle  26 , an internal electrical interface, e.g., electrical socket, where a proximal end  106  of the electrode assembly  100  is plugged into and secured for electric current connection and transmission, and an external electrical interface, e.g., external socket, for plugging in an external cable  30  that transmits electric current from the energy source “G.” All connections may be insulated to prevent dissipation of electric current. A portion of the electrode assembly  100 , e.g., a proximal end of the electrode assembly, extends into working element  24  and operably couples to a drive mechanism operably associated with one or more components, e.g., working head  24 , associated with the resectoscope  20 . The drive mechanism is configured for axial translation of the electrode assembly  100  such that the electrode assembly  100  is translatable from an initial position within the sheath  22  to a subsequent position outside the sheath  22 . Alternatively, the electrode assembly  100  may be fixedly coupled, i.e., non-translatable, to the distal end of the sheath  22 . In one particular embodiment, a visualization apparatus fits into working element  24 . 
         [0035]    The electrode assembly  100  of the present disclosure is configured to concentrate electrosurgical energy, i.e., current density, at specific points along a cutting electrode  102  associated with the electrode assembly  100  when the electrode assembly  100  is positioned adjacent a target tissue resection site. More particularly, when electrode assembly  100  or portion thereof, e.g., a distal end including a cutting electrode  102  and return electrode  104 , is positioned adjacent the target tissue resection site and within a conductive medium (e.g., saline), one or more components or configurations associated with the electrode assembly  100  improves hemostatic efficacy at the target tissue resection site by limiting the amount of current flowing back to the return electrode  104  such that a desired tissue effect is achieved at the target tissue resection site. 
         [0036]    With reference now to  FIG. 2 , an embodiment of the electrosurgical electrode assembly  100  is shown. Electrode assembly  100  may be fabricated from a conductive type material, such as, for example, stainless steel, tungsten, copper, etc. or may be coated with an electrically conductive material. In the embodiment illustrated in  FIG. 2 , electrode assembly  100  is fabricated from stainless steal. Electrode assembly  100  includes a proximal end  107  that is disposed in electrical communication with the generator “G” via the internal socket and external socket configuration described above. 
         [0037]    Electrode assembly  100  is defined by two laterally spaced-apart longitudinal sections  106  and  108  that are parallel to a longitudinal axis “A-A” defined by the sheath  22  ( FIG. 1 ). Each longitudinal section  106  and  108  culminates at a distal tip  110  having a cutting electrode  102  with loop geometry. Each longitudinal section  106  and  108  includes a respective generally arcuate or bent section  112  and  114 . Bent sections  112  and  114  are disposed at a proximal end of the cutting electrode  102  and provide a transition in the orientation of the longitudinal sections  106  and  108  such that the cutting electrode  102  is oriented in generally orthogonal relation with respect to the longitudinal sections  106  and  108 , as best seen in  FIG. 2 . Bent sections  112  and  114  include a relatively large radius of curvature (when compared to a radius of curvature of the loop geometry associated with the cutting electrode  102 ) which may result in a high current density developing at the bent sections  112  and  114  when electrosurgical energy is transmitted to the cutting electrode  102  and the cutting electrode  102  and return electrode  104  are submerged in a conductive medium; the significance of which described in greater detail below. Cutting electrode  102 , as is conventional in the art, is in electrical communication with an outgoing electrical path of the generator “G.” Cutting electrode  102  receives electrosurgical energy from the generator “G” and is configured to generate a current at a target tissue resection site. To this end, cutting electrode  102  may have one or more suitable types of loop geometries. Suitable cutting electrode  102  loop geometries include but are not limited to radial, circular, elliptical, curved, rounded, bowed, arc, arch, crescent, semicircle, roller cylinder and so forth. The cutting electrode loop may also be malleable to form one or more of the aforementioned geometries. The loop size diameter of the cutting electrode  102  may range from about 3 mm to about 10 mm, or any size that will fit in a commercially available resectoscope. In the embodiment illustrated in  FIGS. 1 and 2 , cutting electrode  102  includes a wire loop configuration. Alternatively, cutting electrode  102  may include a band loop configuration, wing loop configuration or other suitable loop configuration. Cross-section shapes of the wire loop configuration may include circular, hemicircular (or any portion of a circle), square, rectangular, triangular, or polygonal shapes such as hexagon, octagon, flat plate, and combinations of the foregoing. The cross-section diameter of the wire loop configuration of the cutting electrode  102  may range from about 0.25 mm to about 4 mm. In certain embodiments the cross-section diameter of the wire loop may vary, as described in greater detail below. 
         [0038]    One or more return electrodes  104  are operably disposed on the electrode assembly  100  and in electrical communication with a return electrical path of the generator “G.” In the embodiment illustrated in  FIG. 2 , a pair of return electrodes  104   a  and  104   b  is disposed in a fixed spaced-apart relation with respect to each other and cutting electrode  102 . More particularly, the pair of return electrodes  104   a  and  104   b  is operably disposed on a respective longitudinal section  106  and  108 . Alternatively, a return electrode  104  may be operably disposed on one of the longitudinal sections, e.g., longitudinal section  106 . Each of return electrodes  104   a  and  104   b  are positioned adjacent a respective bent section  112  and  114 . Return electrodes  104   a  and  104   b  may be fabricated from any suitable conductive (or partially conductive) material. More particularly, return electrodes  104   a  and  104   b  are fabricated from a material that is equally or less conductive than the material of the cutting electrode  102 . In one particular embodiment, return electrodes  104   a  and  104   b  are fabricated from stainless steal. In certain embodiments, return electrodes  104   a  and  104   b  are fabricated from a material that is equally or more conductive than the material of the cutting electrode  102 . 
         [0039]    A layer of insulative coating  116  is operably disposed on a portion of the electrode assembly  100 . In the embodiment illustrated in  FIGS. 1 and 2 , a layer of insulative coating  116  is operably disposed between the return electrodes  104   a  and  104   b  and cutting electrode  102  and, more particularly, a layer of insulative coating is disposed along the bent sections  112  and  114 . Insulative coating  116  may be made from any suitable material including but not limited to Teflon®, Teflon® polymers, silicone and the like. 
         [0040]    In use, initially, electrode assembly  100  including cutting electrode  102  and return electrodes  104  and  104   b  is positioned within sheath  22  of the resectoscope. Sheath  22  is inserted into a urethra of a patient. Electrode assembly  100  including cutting electrode  102  and return electrodes  104   a  and  104   b  are deployed via movable handle  26  of resectoscope  22  from within the sheath  22  (and submerged within the conductive medium, e.g., saline) to an area adjacent a target tissue resection site, e.g., prostate of a patient. Thereafter, electrosurgical energy is transmitted to the cutting electrode  102 . It is noted, the radius of curvature typically associated with bent sections of conventional electrode assemblies is larger compared to a radius of curvature associated with cutting electrodes associated with the same electrode assemblies. Accordingly, in conventional electrode assemblies, the proximity of the bent sections with respect to one or more return electrodes associated with the electrode assemblies provide a return path of least resistance for current (when compared to the target tissue resection site) effectively shunting a fraction of the current to the return electrode(s). Shunting a fraction of the current through the return electrode(s) may decrease the current density at the cutting electrode, which, in turn, decreases the hemostatic efficacy provided by the electrode assembly during a resection procedure, e.g., a TURP procedure. In accordance with the present disclosure, providing an insulative coating  116  in a manner as described herein, minimizes and/or prevents high current densities from developing adjacent the bent sections  112  and  114  during transmission of electrosurgical energy to the cutting electrode  102 . Accordingly, an optimum amount of current is shunted through the return electrodes  104   a  and  104   b  and current density is concentrated at the cutting electrode  102  such that hemostatic efficacy at the target tissue resection site and power transfer from the generator “G” to the cutting electrode  102  is maximized with the electrode assembly  100 . 
         [0041]    With reference to  FIGS. 3A and 3B , an alternate embodiment of electrode assembly  100  is shown and designated electrode assembly  200 . Electrode assembly  200  is substantially similar to that of electrode assembly  100  and so as not to obscure the present disclosure with redundant information, only those features that are unique to electrode assembly  200  are described in detail herein. Electrode assembly  200  is described in terms of use with resectoscope  20 . Accordingly, only those operative components associated with resectoscope  20  necessary to facilitate understanding of the electrode assembly  200  are described in detail herein. 
         [0042]    Electrode assembly includes a dielectric shield  220 . Dielectric shield  220  may be made from any suitable material including but not limited to, flouropolymer, polyimide, polyamide, polyaryl sulfone, silicone plastic and the materials described above with respect to the insulative material  116 . Dielectric shield  220  may have any suitable configuration. In the embodiment illustrated in  FIGS. 3A and 3B , dielectric shield  220  includes a generally arcuate or concave configuration. Dielectric shield  220  is operably coupled to electrode assembly  200 . More particularly, dielectric shield  220  operably couples to each of a pair of longitudinal sections  206  and  208  at distal end of the electrode assembly  200  adjacent bent sections  212  and  214 . Dielectric shield  220  extends toward and past a cutting electrode  202  such that dielectric shield  220  is positioned distally relative to the cutting electrode  202 . Positioning the dielectric shield  220  distally relative to the cutting electrode  202  increases a return path for current through a conductive medium, e.g., saline, to one or more return electrodes  204 , e.g., return electrodes  204   a  and  204   b , associated with electrode assembly  200  when the electrode assembly  200  including cutting electrode  202  and return electrodes  204   a  and  204   b  are positioned within the saline. Essentially, the impedance at the return electrodes  204   a  and  204   b  is higher than at the target tissue resection site resulting in a greater concentration of current at the cutting electrode  202  and adjacent the target tissue resection site. Dielectric shield  220  may be secured to the electrode assembly  200  by any securement method(s) and/or device(s) including but not limited to soldering, brazing, welding, etc. In the embodiment illustrated in  FIGS. 3A and 3B , dielectric shield  220  is welded to each of the longitudinal sections  206  and  208 . Alternatively, dielectric shield  220  may be operably associated with the resectoscope  20  and positionable adjacent cutting electrode  202  during a TURF procedure. Dielectric shield  220  may have any suitable dimensions, e.g., width, height, thickness, etc. In one particular embodiment, a thickness of dielectric shield  220  ranges from about 0.005 inches to about 0.100 inches. 
         [0043]    Operation of a resectoscope  20  with an electrode assembly  200  is substantially similar to that of electrode assembly  100 . In use, electrode assembly  200  including dielectric shield  220 , cutting electrode  202  and return electrodes  204   a  and  204   b  is deployed via movable handle  26  of resectoscope  22  from within the sheath  22  (and submerged within the conductive medium, e.g., saline) to an area adjacent a target tissue resection site. Dielectric shield  220  increases a return path for current through the saline to return electrodes  204   a  and  204   b . The impedance at the return electrodes  204   a  and  204   b  is higher than at the target tissue resection site resulting in a greater concentration of current at the cutting electrode  202  and adjacent the target tissue resection site. Accordingly, an optimum amount of current is shunted through the return electrodes  204   a  and  204   b  and current density is concentrated at the cutting electrode  202  such that hemostatic efficacy at the target tissue resection site and power transfer from the generator “G” to the cutting electrode  202  is maximized with the electrode assembly  200 . 
         [0044]    With reference to  FIGS. 4A and 4B , and initially with reference to  FIG. 4A , an alternate embodiment of electrode assemblies  100  and  200  is shown and designated electrode assembly  300 . Electrode assembly  300  is substantially similar to that of electrode assemblies  100  and  200 . So as not to obscure the present disclosure with redundant information, only those features that are unique to electrode assembly  300  are described in detail herein. Electrode assembly  300  is described in terms of use with resectoscope  20 . Accordingly, only those operative components associated with resectoscope  20  necessary to facilitate understanding of the electrode assembly  300  are described in detail herein. 
         [0045]    In accordance with the present disclosure, hemostasis is a combination of heating depth and energy per volume. Heating depth and/or energy per volume can both be modified by varying a distance “d” between a cutting electrode, e.g., a cutting electrode  302 , and one or more return electrodes, e.g., a return electrode  304  including a pair of return electrodes  304   a  and  304   b . The relationship of heating depth and energy per volume versus a distance between cutting electrode  302  and return electrodes  304   a  and  304   b  is illustrated in  FIG. 4B . At a distance where “d” is equal to zero, e.g., “d0”, cutting electrode  302  and return electrodes  304   a  and  304   b  are shorted together. As the distance “d” increases between the cutting electrode  302  and return electrodes  304   a  and  304   b , the behavior of both heating depth and energy per volume will approach that of a monopolar electrocautery system (see  FIG. 4B  at distance “d3”) that includes a cutting electrode and one or more return electrodes positioned on a patient&#39;s body. At some intermediate distance “d” (e.g., a distance “d2” where “d1”&lt;“d2”&lt;“d3”), the energy volume is higher in a bipolar electrocautery system when compared to a monopolar electrocautery system. In accordance with the present disclosure, this behavior is utilized to develop an electrode assembly  300  that maximizes hemostasis and energy per volume at a target tissue resection site, with minimal heating depth required at the target tissue resection site resulting in less collateral damage to adjacent tissue. 
         [0046]    To this end, cutting electrode  302  and return electrodes  304   a  and  304   b  are in a fixed spaced-apart relationship relative to each other and separated at a distance “d2” where “d1”&lt;“d2”&lt;“d3.” In one particular embodiment, cutting electrode  302  and return electrodes  304   a  and  304   b  are separated by a distance “d2” where “d2” ranges from about 3 mm to about 10 mm. In one particular embodiment, cutting electrode  302  and return electrodes  304   a  and  304   b  are separated by a distance “d2” that is equal to 5 mm. This distance “d2” permits sufficient time for current density at the cutting electrode  302  to build-up without interference from the return electrode  304 , i.e., shunting effect of current through saline to the return electrodes  304   a  and  304   b , such that tissue may be cut. 
         [0047]    In an embodiment ( FIG. 4C ), electrode assembly  300  may be designed with a user-selectable distance “d” interface. In this instance, the distance between the cutting electrode  302  and return electrodes  304   a  and  304   b  may be varied before a TURP procedure or, in some instances, during a TURP procedure such that a desired tissue effect can be achieved at a target tissue site, e.g., resection of tissue with adequate hemostasis to tissue at the target tissue site. With this purpose in mind, each of longitudinal sections  306  and  308  may include a respective substantially hollow internal portion  306   a  and  308   a  configured to slidably receive corresponding elongated portions  302   a  and  302   b  associated with the cutting electrode  302 . More particularly, a mechanical interface (e.g., a friction fit mechanical interface or a indent and detent interface between the internal portions  306   a  and  308   a  and the corresponding elongated portions  302   a  and  302   b ) maintains the cutting electrode  302  in a substantially fixed, spaced-apart relation with respect to the return electrodes  304   a  and  304   b  that are operably positioned on respective elongated portions  306  and  308 . More particularly, in the embodiment illustrated in  FIG. 4C , one or more detents  320  (three detents shown for illustrative purposes) operably disposed along a length of each of the elongated portions  302   a  and  302   b  is configured to releasably engage one or more corresponding indents  322  (shown phantomly) operably disposed along a length of the internal sections  306   a  and  308   a . In this instance, when a predetermined force is applied to the cutting electrode  302 , the elongated portions  302   a  and  302   b , and/or the elongated sections  306  and  308 , the detent(s)  320  is forced out of engagement with the indent(s)  322  such that the cutting electrode  302  (including elongated portions  302   a  and  302   b  associated therewith) are movable relative to the longitudinal sections  306  and  308 . More particularly, the cutting electrode  302  including elongated portions  302   a  and  302   b  associated therewith may be “pushed” proximally into and/or “pulled” distally away from the corresponding internal portions  306   a  and  308   a  associated with the longitudinal sections  306  and  308  (see directional arrow “F” in  FIG. 4C , for example). 
         [0048]    Operation of a resectoscope  20  with an electrode assembly  300  is substantially similar to that of electrode assemblies  100  and  200 . In use, electrode assembly  300  including cutting electrode  302  and return electrodes  304   a  and  304   b  is deployed via movable handle  26  of resectoscope  22  from within the sheath  22  (and submerged within the conductive medium, e.g., saline) to an area adjacent a target tissue resection site. Cutting electrode  302  and return electrodes  304   a  and  304   b  are separated by a distance “d2” where “d2” ranges from about 3 mm to about 5 mm. As noted above, this distance “d2” permits sufficient time for current density at the cutting electrode  302  to build-up without interference from the return electrode  304  (i.e., shunting effect of current through saline to the return electrodes  304   a  and  304   b ) such that tissue may be cut. Accordingly, an optimum amount of current is shunted through the return electrodes  304   a  and  304   b  and current density is concentrated at the cutting electrode  302  such that hemostatic efficacy at the target tissue resection site and power transfer from the generator “G” to the cutting electrode  302  is maximized with the electrode assembly  300 . 
         [0049]    With reference to  FIG. 5 , an alternate embodiment of the electrode assemblies  100 ,  200  and  300  is shown and designated electrode assembly  400 . Electrode assembly  400  is substantially similar to that of electrode assemblies  100 ,  200  and  300 . So as not to obscure the present disclosure with redundant information, only those features that are unique to electrode assembly  400  are described in detail herein. Electrode assembly  400  is described in terms of use with resectoscope  20 . Accordingly, only those operative components associated with resectoscope  20  necessary to facilitate understanding of the electrode assembly  400  are described in detail herein. 
         [0050]    Cutting electrode  402  includes a cross-section loop diameter that varies. More particularly, a top portion  402   a  of the cutting electrode  402  is thicker than a bottom portion  402   b  of the cutting electrode  402 . In this instance, bottom portion  402   b  of cutting electrode  402  provides a radius of curvature that is smaller than a radius of curvature of a top portion  402   a  of the cutting electrode  402 . Accordingly, an electric field at the bottom portion  402   b , i.e., having the smaller radius of curvature, is increased resulting in an increase in current density at the bottom portion  402   b  and adjacent a target tissue resection site. Top portion  402   a  and bottom portion  402   b  may have any suitable diameter. In the embodiment illustrated in  FIG. 5 , bottom portion  402   b  has a diameter that ranges from about 0.0012 inches to about 0.0016 inches at its thinnest point. As illustrated in  FIG. 5 , the cross-section diameter of the cutting electrode  402  gradually increases from the bottom portion  402   b  toward the top portion  402   a . This gradual increase prevents “hot spots” from developing across portions of the cutting electrode  402 . Varying the cross-section diameter of the cutting electrode  402  may provide one or more additional advantages when compared to certain conventional electrode assemblies. More particularly, the thicker top portion  402   a , which is less likely to “breakdown,” e.g., arc, of the cutting electrode  402  may be utilized for coagulating and the thinner bottom portion  402   b  of the cutting electrode  102 , which is more likely to arc, may be used for cutting. 
         [0051]    Operation of a resectoscope  20  with an electrode assembly  400  is substantially similar to that of electrode assemblies  100 ,  200  and  300 . In use, electrode assembly  400  including cutting electrode  402  and a return electrodes  404  including return electrodes  404   a  and  404   b  are deployed via movable handle  26  of resectoscope  22  from within the sheath  22  (and submerged within the conductive medium, e.g., saline) to an area adjacent a target tissue resection site. Bottom portion  402   b  of cutting electrode  402  provides a radius of curvature that is smaller than a radius of curvature of a top portion  402   a  of the cutting electrode  402 . Accordingly, the electric field at the bottom portion  402   b  is larger resulting in an increase in current density at the bottom portion  402   b  and adjacent the target tissue resection site. Accordingly, an optimum amount of current is shunted through the return electrodes  404   a  and  404   b  and current density is concentrated at the cutting electrode  402  such that hemostatic efficacy at the tissue resection site and power transfer from the generator “G” to the cutting electrode  402  is maximized with the electrode assembly  400 . 
         [0052]    With reference to  FIG. 6 , an alternate embodiment of the previously described electrode assemblies  100 ,  200 ,  300  and  400  is shown and designated electrode assembly  500 . Electrode assembly  500  is substantially similar to that of electrode assemblies  100 ,  200 ,  300  and  400 . 
         [0053]    In conventional electrode assemblies, during initiation of a cutting pass of a cutting electrode, a delay is typically required for an arc discharge to develop at the cutting electrode. This delay may be attributed to a low impedance of the conductive medium, e.g., saline, surrounding the cutting electrode when the cutting electrode is initially submerged in the saline. In accordance with present disclosure, the cutting electrode  502  includes one or more types of surface finishes that promotes and/or facilitates vapor bubble adhesion or minimizes the energy required for bubble nucleation on the cutting electrode  502 , which, in turn, minimizes the time delay for an arc to develop at the cutting electrode  502 . To this end, cutting electrode  502  includes a surface finish that includes a hydrophobic finish  520  (shown phantomly for illustrated purposes), a textured finish (e.g., a pitted finish  522 ), and/or combination thereof. In the embodiment illustrated in  FIG. 5  a plurality of pits  522  is operably disposed along a length of the cutting electrode  502  with a hydrophobic coating  520  substantially surrounding the cutting electrode  502  including the plurality of pits  522 . 
         [0054]    Operation of a resectoscope  20  with an electrode assembly  500  is substantially similar to that of electrode assemblies  100 ,  200 ,  300  and  400 . In use, electrode assembly  500  including cutting electrode  502  and a return electrode  504  (comprised of return electrodes  504   a  and  504   b ) is deployed via movable handle  26  of resectoscope  22  from within the sheath  22  (and submerged within the conductive medium, e.g., saline) to an area adjacent a target tissue resection site. Cutting electrode  502  includes a surface finish that includes a combination of a hydrophobic finish  520  coating the cutting electrode  502  and plurality of pits  522 . The surface finish of the cutting electrode  502  promotes or facilitates vapor bubble adhesion or minimizes the energy required for bubble nucleation on the cutting electrode  502 , which, in turn, minimizes the time delay for an arc to develop at the cutting electrode. Accordingly, an optimum amount of current is shunted through the return electrodes  504   a  and  504   b  and current density is concentrated at the cutting electrode  502  such that hemostatic efficacy at the tissue resection site and power transfer from the generator “G” to the cutting electrode  502  is maximized with the electrode assembly  500 . 
         [0055]    From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, in an embodiment, a controller  600  ( FIG. 1 ) may be in operative communication with the generator “G” and/or resectoscope  20  with one or more of the previously described electrode assemblies, e.g., electrode assembly  300 , operably coupled to the resectoscope  20 . Controller  600  may include one or more modules configured to monitor and/or control one or more electrical parameters (or other suitable parameters) associated with the electrode assembly  300 . More particularly, a distance control module  602  may be configured to “virtually” alter the distance between the return electrodes  304   a  and  304   b  and the cutting electrode  302  such that specific attributes associated with a desired point along a control curve, e.g., a control curve similar to the curve illustrated in  FIG. 4B , may be obtained without actually moving either of the cutting electrode  302  or the longitudinal sections  306  and  308 . More particularly, each of the return electrodes  304   a  and  304   b  is segmented into one or more return path segments collectively providing a return path for current. More particularly, the distance control module  602  may be configured to selectively open or close each of the return path segments such that the return path for current may be controlled. Thus, in an instance where a distance “d” needs to be increased, the distance control module  602  may open one or more return path segments, e.g., a distal most return segment associated with each of the return electrodes  304   a  and  304   b , such that current is prevented from returning through the distal most return segment associated with each of the return electrodes  304   a  and  304   b  effectively increasing the distance of between the return electrodes  304   a  and  304   b  and the cutting electrode  302 . 
         [0056]    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.