Abstract:
An electrosurgical scalpel for a gas-assisted electrosurgical system. The electrosurgical scalpel has a dielectric portion and a conductive portion. The dielectric portion forms a substantial majority of the outer surface of the scalpel such that the conductive portion is only exposed along a thin edge of the scalpel. The dielectric portion provided stiffness to the very thin conductive portion and causes energy to be concentrated at the thin edge of the scalpel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    None. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    None. 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to electrosurgical systems and methods, and more particularly, to electrodes for gas-assisted electrosurgical systems and methods. 
         [0005]    2. Brief Description of the Related Art 
         [0006]    The standard means for controlling traumatic and surgical blood loss are electrosurgical generators and lasers which respectively direct high-frequency electrical currents or light energy to localize heat in bleeding vessels so as to coagulate the overlying blood and vessel walls. Hemostasis and tissue destruction are of critical importance when removing abnormal tissue during surgery and therapeutic endoscopy. For monopolar electrosurgery electrical energy originates from an electrosurgical generator and is applied to target tissue via an active electrode that typically has a small cross-sectional surface-area to concentrate electrical energy at the surgical site. An inactive return electrode or patient plate that is large relative to the active electrode contacts the patient at a location remote from the surgical site to complete and electrical circuit through the tissue. For bipolar electrosurgery, a pair of active electrodes are used and electrical energy flows directly through the tissue between the two active electrodes. 
         [0007]    U.S. Pat. No. 4,429,694 to McGreevy disclosed a variety of different electrosurgical effects that can be achieved depending primarily on the characteristics of the electrical energy delivered from the electrosurgical generator. The electrosurgical effects included pure cutting effect, a combined cutting and hemostasis effect, a fulguration effect and a desiccation effect. Fulguration and desiccation sometimes are referred to collectively as coagulation. 
         [0008]    Another method of monopolar electrosurgery via argon plasma technology was described by Morrison in U.S. Pat. No. 4,040,426 in 1977 and by McGreevy in U.S. Pat. No. 4,781,175. This method, referred to as argon plasma coagulation (APC) or argon beam coagulation (ABC) is a non-contact monopolar thermoablative method of electrocoagulation that has been widely used in surgery for the last twenty years. In general, APC involves supplying an ionizable gas such as argon past the active electrode to target tissue and conducting electrical energy to the target tissue in ionized pathways as non-arcing diffuse current. Canady described in U.S. Pat. No. 5,207,675 the development of APC via a flexible catheter that allowed the use of APC in endoscopy. These new methods allowed the surgeon, endoscopist to combine standard monopolar electrocautery with a plasma gas for coagulation of tissue. 
         [0009]    APC has been demonstrated to be effective in the coagulation of blood vessels and human tissue during surgery. APC functions in a noncontact manner. The electrical current is initiated only when the tip of the handpiece or catheter is within one centimeter of the target tissue and produces a homogenous 1 mm to 2 mm well-delineated eschar. The eschar created by APC is further characterized by a decrease absence of charring and carbonization compare to eschar resulting from conventional electrosurgical fulguration. The eschar remains firmly attached to the tissue, in contrast to other coagulation modalities where there is an overlying charred layer of coagulated blood. There is minimal tissue necrosis with APC. 
         [0010]    In U.S. Pat. Nos. 5,217,457 and 5,088,997 to Delahuerga et al. disclosed a device for performing procedure referred to as “argon shrouded cut.” The device was an electrosurgical pencil having an exposed electrode with a distal end defining a tip for cutting biological tissue and a nose piece mounted about the electrode to define a pathway for a stream of inert gas which shrouds the electrode at or near its tip. When in coagulation mode, a convergent stream of inert gas was directed directly onto the tip of the electrode. In coagulation mode, the voltage was sufficient to initiate an electrical discharge in the inert gas. In cut mode, the stream of ionized gas was directed to impinge obliquely on the electrode at a point adjacent to but away from the tip of the electrode. In cutting mode, the open circuit voltage was generally not high enough to continuously plasmatize the inert gas and initiate and maintain an electrical discharge. Accordingly, in cut mode the function of the inert gas is to provide a shroud around the electrode rather than to initiate electrical discharge. 
         [0011]    A multitude of literature exists that discloses and discusses various commercially available electrosurgical generators and the voltage waveforms produced by those generators. For example, A. Erwine, “ESU-2000 Series Product Overview A Paradigm Shift in Electrosurgery Testing Technology and Capability Is Here,” BC Group International, Inc. (2007) describes electrosurgical generators from ERBE Elektromedizin GmbH and ConMed Corporation, among others. 
         [0012]    In U.S. Patent Application Publication No. US-2013-0296848, Canady et al. described electrosurgical systems and methods using argon plasma during cutting modes of operation. The disclosed electrosurgical device had a handpiece or pencil  100  having a rigid housing  110  and telescoping nozzle or tip  120 . The rigid housing may be formed, for example, from molded sides  102  and  104 . The two sides  102 ,  104  are joined to form housing  110  having a hollow chamber within. Within the housing  110  is a needle electrode  230 , electrode tubing  270  and a fiberglass plate  240 . The needle electrode  230  extends through the electrode tubing  270 . The electrode tubing additional has within it a channel, tube or other means for conducting the inert gas from the distal end of tubing  220  through the electrode tubing  270  and out of the electrode tubing  270 . The inert gas leaving the channel in the electrode tubing then passes out of an opening at the distal end of the nozzle  120 . The fiberglass plate  240  and electrode  230  are connected to electrical cable assembly  210 . The electrode tubing is connected at its distal end to the PVC hose tubing  220 . An O-ring  260  is placed between the telescoping nozzle and the electrode tubing to form a seal there between. A ceramic tip  250  may be placed at a distal end of the telescoping tip or nozzle  120  to protect the nozzle  120  from heat damage where the electrode passes through an opening at the distal end of the nozzle  120 . The electrical cable assembly extends from a proximal end of the housing  110  and has at its distal end a plug  212 . During operation of the device, the connector  212  is connected to an electrosurgical generator. The PVC hose tubing  220  also extends from the proximal end of the housing  110  and has at its distal end a gas connector body  222 , a gas connector tip  224  and an O-ring  226 . During operation of the device, the gas connector assembly ( 222 ,  224 ,  226 ) is connected to a source of an inert gas such as argon. The housing  110  has a plurality of opening or holes for accommodating a plurality of controls or buttons  140 ,  150 ,  160 . The telescoping nozzle or tip  120  has a control element  122  extending through a slot  112  in the housing  110 . The control element, tab, know or slider  122  is used by a surgeon to move the telescoping tip  120  into or out of an opening in a distal end of the housing  120 . Three controls or buttons  140 ,  150 ,  160 , extend out of openings in the housing  110  and have springs  142 ,  152 ,  162  between them and fiberglass plate  240  to bias the controls or buttons away from the plate or connector  240 . 
         [0013]    The electrosurgical device of U.S. Patent Application Publication No. US-2013-0296848 could be operated, for example, in four different modes: conventional cut mode, conventional coagulation mode, argon plasma coagulation mode, and hybrid plasma cut mode. The eschar resulting from cutting and coagulation in the hybrid plasma cut mode in accordance with the present invention is substantially better than conventional fulguration, cutting and argon plasma coagulation techniques. In addition there is substantial absence of charring, carbonization, tissue necrosis and destruction of adjacent tissue. Thus, tissue can be precisely cut and the adjacent vessels simultaneously sealed with minimal depth of injury, tissue necrosis, eschar and carbonization. 
         [0014]    Any generator that provides high-frequency voltage to ionize the inert gas to form a gas stream can be used. Preferred generators include the Canady Plasma™ Electrosurgery Unit model (SS-601 MCa) and the Canady Plasma™ Electrosurgery Unit model (SS-200E) that are preferably used with the Argon plasma units Canady Plasma™ Argon 4 Coagulator (CPC 4) and Canady Plasma™ Argon 2 Coagulator (CPC 2), respectively. The CPC 4 provides a controlled flow of inert gas to the electrosurgical device during argon plasma coagulation mode and in hybrid plasma cut mode. The flow rate and the power can be manually set. In a coagulation mode, the generator delivers, for example, a peak-to-peak voltage of less than 9000 volts. In a cut mode, for example, the generator delivers a peak-to-peak voltage of less than 3800 volts. Most preferably, a peak-to-peak voltage of 100 to 9000 volts is delivered by the generator. Any accessory devices could be attached to the electrosurgical unit/plasma unit combination. Exemplary devices are an electrosurgical device (a handpiece) or an argon plasma flexible probe (catheter), rigid or laparoscopic. 
         [0015]    For operating the electrosurgical device disclosed in U.S. Patent Application Publication No. US-2013-0296848, high-frequency current can be activated by two push buttons for the conventional cut mode and the conventional coagulation mode, respectively. Argon gas may be delivered by activating a third push button. This activation will allow the argon plasma coagulation mode and the hybrid plasma cut mode. The plasma cut mode will cut and coagulate the tissue at the same time. It can be easily switched between the different modes by activating the respective buttons. The plasma or electrical current can also be activated by a footswitch. 
         [0016]    In U.S. Patent Application Publication No. US-2013-0296848, the electrosurgical scalpel took the form of a needle or wire. Such a form is common with conventional electrosurgical staplers. Electrosurgical scalpels, however, can take many other forms, for example, as shown in U.S. Pat. No. 7,066,936 to Ryan, U.S. Pat. No. 6,610,057 to Ellman et al., U.S. Pat. No. 5,951,551 to Erlich, 
       SUMMARY OF THE INVENTION 
       [0017]    In a preferred embodiment, the present invention is an attachment for a gas-assisted electrosurgical device. The attachment comprises a housing, a channel within said housing, a connector for connecting said channel to a gas source, an electrosurgical scalpel having a width at least three times its thickness, said electrosurgical scalpel comprising and a connector for connecting said electrosurgical scalpel to an electrosurgical generator. The electrosurgical scalpel has a dielectric portion and a conductive portion. The dielectric provide stiffness to the electrosurgical scalpel. The conductive portion is exposed only along the thickness of said electrosurgical scalpel. The conductive portion of said electrosurgical scalpel may be a conductive plate having opposing flat surfaces formed by its width and length and an edge formed by its thickness. The dielectric portion may be a dielectric coating on said opposing flat surfaces of said conductive plate. The dielectric coating may form flat or contoured surfaces on the width of the scalpel. The electrosurgical attachment may further have a connector for connecting said scalpel to an electrosurgical handpiece. 
         [0018]    In another embodiment, the dielectric portion is a dielectric plate or slab having a pair of opposing surfaces formed by its width and an edge formed by its thickness. The conductive portion of said electrosurgical scalpel comprises a conductive wire along said edge of said dielectric plate. The dielectric coating may have flat or contoured outer surfaces. 
         [0019]    Still other aspects, features, and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating a preferable embodiments and implementations. The present invention is also capable of other and different embodiments and its several details can be modified in various obvious respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description and the accompanying drawings, in which: 
           [0021]      FIG. 1  is a perspective view of a prior art electrosurgical handpiece having its electrode refracted within its housing. 
           [0022]      FIG. 2A  is a perspective view of a prior art electrosurgical attachment having its electrode extending out from a distal end of its housing. 
           [0023]      FIG. 2B  is an assembly drawing of a prior art electrosurgical attachment of  FIG. 2A . 
           [0024]      FIG. 3A  is a perspective view of an electrode for an electrosurgical handpiece in an extended position in accordance with a first embodiment of the present invention. 
           [0025]      FIG. 3B  is a close-up perspective view of the electrode of  FIG. 3A  for an electrosurgical handpiece in an extended position in accordance with a first embodiment of the present invention. 
           [0026]      FIG. 3C  is a perspective view of an electrode for an electrosurgical handpiece in a retracted position in accordance with a first embodiment of the present invention. 
           [0027]      FIG. 3D  is a close-up perspective view of the electrode of  FIG. 3C  for an electrosurgical handpiece in a retracted position in accordance with a first embodiment of the present invention. 
           [0028]      FIG. 4A  is a perspective view of an electrode for an electrosurgical handpiece in an extended position in accordance with a second embodiment of the present invention. 
           [0029]      FIG. 4B  is a close-up perspective view of the electrode of  FIG. 4A  for an electrosurgical handpiece in an extended position in accordance with a second embodiment of the present invention. 
           [0030]      FIG. 4C  is a perspective view of an electrode for an electrosurgical handpiece in a retracted position in accordance with a second embodiment of the present invention. 
           [0031]      FIG. 4D  is a close-up perspective view of the electrode of  FIG. 4C  for an electrosurgical handpiece in a retracted position in accordance with a second embodiment of the present invention. 
           [0032]      FIG. 5A  is a perspective view of an electrode for an electrosurgical handpiece in an extended position in accordance with a third embodiment of the present invention. 
           [0033]      FIG. 5B  is a close-up perspective view of the electrode of  FIG. 5A  for an electrosurgical handpiece in an extended position in accordance with a third embodiment of the present invention. 
           [0034]      FIG. 5C  is a perspective view of an electrode for an electrosurgical handpiece in a retracted position in accordance with a third embodiment of the present invention. 
           [0035]      FIG. 5D  is a close-up perspective view of the electrode of  FIG. 5C  for an electrosurgical handpiece in a retracted position in accordance with a third embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0036]    In the context of a hybrid plasma cut system such as is disclosed in U.S. Patent Application Publication No. US-2013-0296848, it has been found that decreasing the exposed surface area of the electrode, and in particular the cutting edge of the electrode, improves the quality of simultaneous cutting and coagulation. By making the electrosurgical scalpel thinner, such as in the form of a thin plate rather than a needle or wire, improves the quality of the cutting and coagulation. Making the scalpel thinner, however, reduces the stability of the electrode and can result in bending of the electrode. In the present invention, a scalpel is formed using a combination of conductive and dielectric material to produce a scalpel of sufficient strength yet limiting the exposed area of the conductive material to achieve improved cutting and coagulation. 
         [0037]    A first preferred embodiment of the present invention is shown in  FIGS. 3A-3D . An electrosurgical handpiece  300  has a housing  310  formed from a rigid material such as plastic or other material known to those of ordinary skill in the art. A nozzle  320  extends from the housing  310  and may be integral with the housing  310  or may be attached to the housing. The housing  310  and the nozzle  320  having a channel therein for conducting gas from a gas source (not shown), through the housing and out a port at the distal end of the nozzle  320 . An electrosurgical scalpel  330  is movably mounted in the nozzle and/or housing such that is can extend out of the nozzle  320  as shown in  FIGS. 3A and 3B  or can be retracted within the housing as shown in  FIGS. 3C and 3D . As shown in  FIG. 3B , the scalpel  330  is formed from a dielectric slab or plate  332 , which provides rigidity to the scalpel. A thin wire  334 , for example, 1 mm or less in diameter, is mounted around the edge of the dielectric slab or plate  332 . With this structure, the wire  334  forms the cutting surface and electrode of the scalpel. The proximal end of the scalpel is connected to a source of electrical current such as an electrosurgical generator. Many different means are known in the art for making that connection. 
         [0038]    A second preferred embodiment of the present invention is shown in  FIGS. 4A-4D . An electrosurgical handpiece  400  has a housing  410  formed from a rigid material such as plastic or other material known to those of ordinary skill in the art. A nozzle  420  extends from the housing  410  and may be integral with the housing  410  or may be attached to the housing. The housing  410  and the nozzle  420  having a channel therein for conducting gas from a gas source (not shown), through the housing and out a port at the distal end of the nozzle  420 . An electrosurgical scalpel  430  is movably mounted in the nozzle and/or housing such that is can extend out of the nozzle  420  as shown in  FIGS. 4A and 4B  or can be retracted within the housing as shown in  FIGS. 4C and 4D . As shown in  FIG. 4B , the scalpel  430  is formed from conductive electrical plate  434  coated on both sides with a dielectric  434 , which provides rigidity to the scalpel  430 . With this structure, the exposed surface of the conductive plate  434  forms the cutting surface and electrode of the scalpel. The proximal end of the scalpel is connected to a source of electrical current such as an electrosurgical generator. Many different means are known in the art for making that connection. 
         [0039]    A third preferred embodiment of the present invention is shown in  FIGS. 5A-5D . An electrosurgical handpiece  500  has a housing  510  formed from a rigid material such as plastic or other material known to those of ordinary skill in the art. A nozzle  520  extends from the housing  510  and may be integral with the housing  510  or may be attached to the housing  510 . The housing  510  and the nozzle  520  having a channel therein for conducting gas from a gas source (not shown), through the housing and out a port at the distal end of the nozzle  520 . An electrosurgical scalpel  530  is movably mounted in the nozzle and/or housing such that is can extend out of the nozzle  520  as shown in  FIGS. 5A and 5B  or can be retracted within the housing as shown in  FIGS. 5C and 5D . As shown in  FIG. 5B , the scalpel  530  is formed from conductive electrical plate  534 . The conductive plate  534  is coated or covered with a dielectric  534 , which provides rigidity to the scalpel  530 . The dielectric  534  is then removed from the cutting edge of the conductive plate  534 , for example, by sanding the edge. With this structure, the exposed surface of the conductive plate  534  forms the cutting surface and electrode of the scalpel. The proximal end of the scalpel is connected to a source of electrical current such as an electrosurgical generator. Many different means are known in the art for making that connection. 
         [0040]    The foregoing description of the preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiment was chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents. The entirety of each of the aforementioned documents is incorporated by reference herein.