Abstract:
A bipolar electrosurgical instrument that is configured for use in MIS and other electrosurgical procedures. The instrument is constructed with a rigid end as a bipolar electrode comprising spaced rounded electrodes. The electrode preferably comprises spaced hemispherically-shaped electrically conductive members projecting from the end of the housing. When energized, a bipolar discharge is generated between the bare ends of the electrode.

Description:
RELATED APPLICATION 
     U.S. application, Ser. No. 09/303,839, filed May 3, 1999, commonly owned, for “Electrosurgical Handpiece For Treating Tissue”, of which the present application is a continuation-in-part. 
     U.S. application, Ser. No. 09/393,286, filed sEP. 10, 1999, commonly owned, for “Electrosurgical Handpiece For Treating Tissue”, of which the present application is a continuation-in-part. 
     U.S. application, Ser. No. 09/425,313, filed Oct. 25, 1999, commonly owned, for “Electrosurgical Handpiece For Treating Tissue”, of which the present application is a continuation-in-part. 
     U.S. application, Ser. No. 09/483,994, filed Jan. 18, 2000, commonly owned, for “Electrosurgical Handpiece For Treating Tissue”, of which the present application is a continuation-in-part. 
     This invention relates to a bipolar electrosurgical handpiece and an activator for an electrosurgical handpiece. 
    
    
     BACKGROUND OF THE INVENTION 
     Our prior application, Ser. No. 09/303,839, describes a novel electrosurgical handpiece for treating tissue in a surgical procedure commonly known as minimally invasive surgery (MIS). Among the features described and claimed in the prior application is an electrosurgical handpiece that can be used in MIS and reduces the danger of excessive heat causing possible patient harm. This is achieved in one embodiment by an electrosurgical handpiece that is bipolar in operation and that is configured for use in MIS. The bipolar operation confines the electrosurgical currents to a small active region between the active ends of the bipolar electrode and thus reduces the possibility that excessive heat will be developed that can damage patient tissue. Moreover, the position of the active region can be controlled to avoid patient tissue that may be more sensitive to excessive heat. Preferably, the handpiece is provided with a dual compartment insulated elongated tube, each of the compartments serving to house one of the two wires of the bipolar electrodes. The electrode for MIS use is preferably constructed with a flexible end controllable by the surgeon so as to allow the surgeon to manipulate the end as desired during the surgical procedure. In a preferred embodiment, the flexible end is achieved by weakening at the end the housing for the electrode, and providing a pull string or wire connected to the weakened housing end and with a mechanism at the opposite end for the surgeon to pull the string or wire to flex the housing end to the desired position. This feature allows the surgeon to position the active electrode end at the optimum location for treating, say, a herniated disk to remove undesired regions and to provide controlled heat to shrink the tissue during surgery. In FIGS. 3-7 of the prior application, a suitable bipolar electrode is described, which comprises a pair of rounded electrodes with spaced flat sides separated by an insulating layer. FIGS. 8-10 illustrate a suitable unipolar electrode construction of the flexible end handpiece. FIG. 12 illustrates how such an electrode can be used for the reduction of herniated disks in a laparoscopic procedure. FIG. 20 shows a scissors end that can be constructed as a bipolar electrode for certain purposes. 
     Our prior application, Ser. No. 09/393,286, describes a modified bipolar electrode construction using the flexible end handpiece, the modified bipolar electrode having spaced prongs. 
     Our prior application, Ser. No. 09/425,313, describes a modified bipolar electrode configured to provide easier flexing of the handpiece end, or more controlled flexing and positioning of the handpiece end. 
     Our prior application, Ser. No. 09/483,994, describes a modified bipolar electrode construction using the flexible end handpiece, the modified bipolar electrode having spaced loops. 
     There is a need in the art for rigid electrodes, i.e., without a flexible end, for treating orthopedic ailments, such as joint ailments of the shoulder and knee, especially in an minimally invasive surgery (MIS) environment, also referred to from time to time as arthroscopy. 
     SUMMARY OF THE INVENTION 
     The present invention is a continuation-in-part of the four prior applications and hereby incorporates by reference the total contents of the four prior applications, Ser. Nos. 09/303,839, 09/393,286, 09/425,313, and 09/483 994. The present invention describes and claims among other things a bipolar electrode comprising spaced rounded electrodes with a rigid non-flexible end. Since the present application otherwise makes use of the same teachings of the prior applications, it was felt unnecessary to repeat in the body of this specification many of the details present in the contents of the prior application. The present description will be confined solely to the modifications in the handpiece or electrode which will still achieve the same benefits as with the constructions of the prior applications. For more details, the reader is directed to the prior applications. 
     The new handpiece end constructions of the present improvement uses the bipolar principle and are configured to provide more controlled distribution of the electrosurgical currents to the tissue to be modulated. 
     In a preferred embodiment, the electrode ends are formed by dual projecting, spaced, rounded electrodes, preferably configured as hemispherical or flattened hemispherical electrodes each connected to a terminal of the bipolar source. In a first preferred embodiment, the hemispherical electrodes project laterally in spaced parallel planes approximately the same distance from the insulated end of the electrode mounted in a rigid handpiece. In a second preferred embodiment, the electrodes are substantially hemispherical in configuration, by which is meant that the electrodes are more elliptically shaped with one axis longer than the transverse axis. By “laterally” is meant that the hemispherical electrodes extend at right angles or at an acute angle, such as 45°, with respect to the longitudinal axis of the handpiece or the electrode shaft. 
     The constructions of the invention will provide the same important benefits not only for MIS of herniated disks but also for other MIS arthroscopic procedures where controlled electrode position and/or controlled heat generation is of importance as described in the prior applications, as well as for general electrosurgical procedures where the volumetric reduction of tissue or ablation of tissue is desirable. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention, like reference numerals designating the same or similar elements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a schematic view of a bipolar electrode according to the invention mounted in a handle or handpiece; 
     FIG. 2 is a perspective view of one form of bipolar electrode according to the invention; 
     FIG. 3 is a side view of the electrode of FIG. 2; 
     FIG. 4 illustrates one way of assembling the electrode of FIG. 2; 
     FIG. 5 is a perspective view of another form of bipolar electrode according to the invention; 
     FIGS. 6 and 7 are a side and a perspective view, respectively, of still another form of bipolar electrode according to the invention; 
     FIGS. 8 and 9 are a side and a perspective view, respectively, of still another form of bipolar electrode according to the invention; 
     FIG. 10 is a perspective view of another form of bipolar electrode according to the invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The reader is directed to the referenced prior applications for a more detailed description of the prior applications which will assist in understanding the improvements offered by the present application. 
     In the present application, FIG. 1 is a schematic view of one form of electrosurgical instrument  10  in accordance with the invention. It comprises a rigid handle  12  with a conventional front end adapted to receive and hold rigidly the shank end (not shown) of an elongated electrode  14  whose working end  16  is shown at the left. The handle  12  is electrically-insulating or if conductive covered with an electrically-insulating coating. Similarly, the electrode elongated shaft  18  is also coated with an electrically-insulating coating, leaving bare the active electrodes  20 ,  22  at the working end  16 . The shaft  18  is long enough to extend through a conventional trocar or channel so that its working end is exposed inside the patient. At the right end of the handle  16  is shown a cable  26  which contains two insulated wires for receiving bipolar electrosurgical currents from a conventional electrosurgical apparatus  28 . 
     FIGS. 1 and 2 illustrate one embodiment of the invention in which the bipolar electrodes  20 ,  22  are configured as part of an overall hemisphere. Each electrode  20 ,  22  is substantially one-half of a hemisphere, with their flat sides  30 ,  32  facing one another and spaced apart by a thin electrically-insulating layer  34 . As will be evident from the drawings, the left end  36  of the shaft  18  is molded of an electrically-insulating plastic, such as Nylon (see FIG. 4) to provide a face  38  facing at a 90° angle to the longitudinal axis  40  of the shaft  18 . Interior channels  42  in the molded end  36  terminate in openings  44  at the face  38 . Located between the holes is a molded insulator  46  with molded pins  48  extending laterally from opposite sides over the openings  44 . The bipolar wires  50 , shown in FIG. 2, extend respectively, through the channels  42  to the openings  44  where they can be soldered, welded or otherwise electrically connected each to one of a pair of quarter-spherically shaped metal members that constitute the active bipolar electrodes  20 ,  22 . One convenient way of mounting the quarter-spherically shaped metal members is to provide holes in their flat sides  30 ,  32  which align with the pins  48  on the separator  34 , and they can be press fitted or otherwise secured, as by adhesive, to the pins. As will be observed, the two quarter-spherically shaped metal members together with the rounded insulator  34  have their outer surfaces extending in a spherical plane and form almost a complete hemispherical body projecting out of its holder  36  with the electrodes  20 ,  22  bare and exposed to apply electrosurgical currents to tissue when contacting same. The two wires  50  are not only insulated from each other so that bipolar electrosurgical voltages can be applied between them, but they are also insulated from the electrode holder  36 . 
     In this description, by “axial” is meant parallel to the long axis of the electrode  40  (horizontal in FIGS.  1  and  3 ). By “lateral” is meant transverse to the long axis  40  of the electrode (vertical in FIGS.  1  and  2 ). “Lateral” is intended to include 90° for the embodiments of FIGS. 1-5, as well as 45° for the embodiments of FIGS. 6-9. The two insulated wires  50  terminate at the right end of the handle  12  in a connector (not shown) having prongs which can be plugged into the standard bipolar socket or cable which connects the assembly to electrosurgical apparatus  28 . 
     Once the surgeon has positioned the working end  16  of the instrument with respect to the tissue to be operated on, he or she then activates the electrosurgical apparatus  28  causing a discharge of bipolar currents between the bare electrodes  20 ,  22  capable of causing excision of or ablation of or shrinkage of tissue or cauterization of a blood vessel in the usual way. Other usable mechanical or electrical structures following the teachings of the prior applications will be appreciated by those skilled in this art. As with the embodiments of the prior application, the insulating tube coating on the shaft  18  will prevent accidental touching of patient tissue by the electrode sides, so that the bipolar discharge is locallized to the spacing between the bare ends  20 ,  22 . The operation can take place in a dry or wet field. The surgeon positions the electrodes  20 ,  22  so as to touch or pass lightly over the tissue to be modulated as needed for the procedure being followed. 
     For example, a suitable metal for the electrodes is brass or stainless steel. A suitable thickness of the insulator  34  is about 0.02-0.04 inches. The diameter of the hemispherical assembly can vary between about 0.2-0.4 inches. Preferably, the insulator thickness is about 0.025 inches and the radius of curvature of each of the quarter-spherical electrode is about 0.12-0.14 inches. The shaft outside diameter is typically about 0.2-0.4 inches. 
     In the second embodiment of FIG. 5, electrode assembly  54 ,  56 , separated by the thin insulator  58 , is more elliptically shaped with its long dimension longer than its transverse dimension. Otherwise, the electrodes are the same. 
     In the third embodiment of FIGS. 6 and 7, there are two differences. First, electrode holder  60  projects at an angle of out 45° (referenced  62 ) with respect to the longitudinal axis  64  of the holder  60 . The electrodes  66  themselves, still forming a hemispherical structure, have holes  68  distributed uniformly about the electrode. As in the other embodiments, the electrodes are spaced apart by a thin insulator  70 . The electrosurgical currents tend to concentrate at discontinuities, in this case represented by the edges bordering each hole. 
     In the fourth embodiment of FIGS. 8 and 9, the electrode  74  is provided with spaced outwardly-projecting points  72  for the purpose of concentrating the electrosurgical currents. 
     In the fifth embodiment of FIG. 10, the electrode  80  in a holder  82  has a flattened hemispherical shape with the electrodes  84  spaced apart by a thin insulator  86 . While the general shape can still be broadly considered as hemispherical, except for the rounded edges, the top is substantially flat so that when placed adjacent or in contact with the tissue, essentially the whole top surface will be effective. A typical overall diameter is about 0.138 inches, and its height above the holder is about 0.020 inches as an exemplary embodiment. 
     The electrosurgical apparatus preferably is an ultra high frequency (RF) radiosurgical energy source, which operates in the range of about 3.8-4.0 MHz. Studies have shown that the 3.8-4.0 MHz frequency range is the preferred RF energy to incise and coagulate tissue because tissue thermal necrosis is minimal and, when interfaced with the electrosurgical electrode of the invention, provides excellent cutting and hemostasis especially for throat procedures. An example of suitable electrosurgical apparatus is the Model SURGITRON Dual-Frequency electrosurgical unit manufactured by and available from Ellman International, Inc. of Hewlett, N.Y. 
     While the invention has been described in connection with preferred embodiments, it will be understood that modifications thereof within the principles outlined above will be evident to those skilled in the art and thus the invention is not limited to the preferred embodiments but is intended to encompass such modifications.