Patent Publication Number: US-10772675-B2

Title: Electrosurgical forceps with cup for supporting tines

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
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     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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     BACKGROUND 
     Electrosurgical forceps have a pair of resilient tines or blades that are used for grasping and coagulating tissue. The tines are typically supported at their proximal ends in a cup filled with a potting material, such as epoxy, which solidifies within the cup. The forceps may be monopolar or bipolar. In monopolar forceps, the tines are welded or otherwise joined to form an electrode in electrical communication with an electrical generator. Current flows from the active electrode through the patient&#39;s tissue to a dispersive electrode in contact with the patient&#39;s skin (which may be at some distance from the forceps) and back to the generator. In bipolar forceps, each tine of the pair comprises an electrode in communication with an electrical generator. Current flows from one tine through the tissue to the other tine. 
     SUMMARY OF THE INVENTION 
     The invention relates to electrosurgical forceps with a cup for supporting the tines. In prior art forceps, the potting material does not always completely fill the interior of the cup, leaving air pockets in various places within the cup. Such air pockets can result in a loosening of the tines within the cup, leading to a misalignment or “scissoring” of the tips at the distal end of the forceps. The present forceps include a support element within the cup that holds the proximal ends of the forceps tines, to minimize or eliminate the “scissoring” effect or misalignment of the tips. 
     In some embodiments, the support element includes a collar surrounding at least a portion of a proximal end of at least one tine. One or more ribs can extend from the collar to provide additional structural support. 
     In some embodiments, an electrosurgical forceps includes a cup comprising a circumferentially extending wall having an outer surface, an inner surface, and an open distal end. A proximal end wall extends across a proximal end of the circumferentially extending wall and has an inner surface. A pair of openings is disposed through the proximal end wall. An interior region is defined within the inner surface of the circumferentially extending wall and the inner surface of the proximal end wall. Terminal pins are disposed in the openings in the proximal end wall, with an end portion of each terminal pin extending proximally out of the cup. The forceps includes a pair of tines, each tine being generally elongated and having a tip at a distal end and a proximal end fixed with the cup. Each tine is connected for electrical communication to one of the terminal pins. A support element within the interior region of the cup is configured to support the tines within the cup. A potting material is provided within the interior region of the cup. 
     In some embodiments, the support element comprises a pair of collars surrounding at least a portion of the proximal ends of the tines. In some embodiments, one or more ribs can extend from the collar across the inner surface of the proximal end wall to the inner surface of the circumferentially extending wall. In some embodiments, a connecting rib can extend between the collars. In some embodiments, at least one of the tines is supported by the support element within the cup. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a side view of bipolar electrosurgical forceps according to an embodiment of the invention; 
         FIG. 2  is a partial cross-sectional plan view of the forceps of  FIG. 1 ; 
         FIG. 3  is a plan view of a tine and terminal pin of the forceps of  FIG. 1 ; 
         FIG. 4  is an end view of the cup of  FIG. 1 ; 
         FIG. 5  a cross-sectional view along line V-V of  FIG. 4 ; 
         FIG. 6  is a cross-sectional view along line VI-VI of  FIG. 4 ; 
         FIG. 7  is a partial cross sectional view along line VII-VII of  FIG. 1 ; and 
         FIG. 8  is a cross-sectional view of a prior art cup. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of electrosurgical forceps  10  with a cup  12  for supporting tines  14 ,  16  is illustrated in  FIGS. 1-3 . The forceps is a bipolar device with first and second tines  14 ,  16  that serve as electrodes. Each of the tines is elongated and extends from a proximal end  18  supported within an electrically insulating cup  12  to a tip  22  at a distal end  24 . The tines are generally flat, and the tips are configured for gripping tissue between opposed surfaces  26  when the tines are grasped by a user and squeezed closed. The tines can be electrically insulated with an insulating material  28  along most of their length from the cup  12  to a location close to the tip  22 . A textured surface  32 , gripping pad, or the like can be provided on each tine at a location where the tine is grasped. The proximal ends  18  are electrically connected in any suitable manner to terminal pins  34  within the cup  12 . In some embodiments, the proximal end  18  of the tine includes a tab  36  to which the terminal pin is attached, such as by crimping, welding, or soldering. The proximal ends attached to the terminal pins are encapsulated within an interior region  42  of the cup  12  using a potting material  44 , such as an epoxy-based material. The tines can include apertures  46  through which the potting material can flow to help affix the tines within the cup. 
     The cup  12  includes a support element  70  (see  FIG. 4 , described further below) that supports one or both tines  14 ,  16  at their proximal ends  18  to more firmly affix the tines within the cup. More particularly, in some instances of prior art forceps, the potting material incompletely fills the cup, leaving one or more air pockets within the cup. The proximal ends of the tines are thereby prone to shifting within the cup, leading to a “scissoring” effect, by which the tips  22  of the forceps at the distal end  24  become misaligned. Such misalignment does not provide optimal operation by the forceps for grasping and coagulating tissue. ( FIG. 8  illustrates a cup of a prior art forceps.) The support element  70  described herein minimizes or eliminates the risk of a “scissoring” effect or misalignment of the tips of the forceps at the distal end. 
     Referring more particularly to  FIGS. 4-7 , the cup  12  is formed with a circumferentially extending wall  52  having an outer surface  54 , an inner surface  56 , and an open distal end  58 . A proximal end wall  62  extends across a proximal end of the circumferentially extending wall  52  and has an inner surface  64 . The interior region  42  is defined within the inner surface  56  of the circumferentially extending wall  52  and the inner surface  64  of the proximal end wall  62 . Two openings  66  are provided through the proximal end wall. A terminal pin  34  is disposed in each opening in the proximal end wall, with end portions of the terminal pins extending proximally out of the cup (see  FIG. 7 ). The tab  36  of each tine is connected for electrical communication to one of the terminal pins, for example, by one or more of crimping, welding, or soldering. In the embodiment illustrated, a sleeve or crimp member  68  is illustrated. 
     In the embodiment shown in  FIGS. 4-7 , the support element includes a pair of collars  72 . Each collar extends from the inner surface  64  of the proximal end wall  62  of the cup with an opening  74  in axial alignment with an associated one of the openings  66  through the proximal end wall  62 . Each collar  72  surrounds at least a portion of the proximal end  18 , for example, a portion of the tab  36 , of one of the tines  14 ,  16 . In some embodiments, a sleeve or crimp member  68  coaxially surrounds the tab  36  of the tine and the terminal pin  34  to maintain an electrical connection therebetween, and is disposed at least partially within the opening  74  of the collar  72 . The inner diameter of the collar opening  74  can be selected so that the sleeve  68  fits firmly within the collar. In some embodiments, the collar can have an inner diameter greater than an inner diameter of the associated opening  66  in the end wall. The inner diameter of the collar can also be selected to support the tine when a sleeve or crimp member is not employed for the electrical connection between the tine and the terminal pin. 
     In some embodiments, the support element  70  can include one or more ribs  82  extending from one or both collars  72  across the inner surface  64  of the proximal end wall  62  to the inner surface  56  of the circumferentially extending wall  52 . In some embodiments, the support element also includes a connecting rib  84  extending across the inner surface of the proximal end wall between the collars  72 . The ribs add further structural rigidity to the cup. Other rib configurations can be used. 
     In some embodiments, the support element  70  is an annular collar that continuously surrounds the proximal end, for example, the tab, of the tine (as shown in  FIGS. 4-7 ). In some embodiments, the collar can surround the proximal end discontinuously, as long as a sufficient amount of the proximal end is supported. For example, the collar can be provided as discontinuous circular sectors symmetrically located around the tine. In some embodiments, the opening  74  through the collar can have a circular configuration. (See  FIG. 4 .) In some embodiments, the opening through the collar can have a configuration complementary with the proximal end of the tine, for example, a generally rectangular configuration to mate with a generally flat tab. In some embodiments, the support element can include a single collar to support one of the tines. 
     The cup  12  can be made from an electrically insulating material, such as thermoplastic rubber, polypropylene, nylon, polyvinylidene fluoride (PVDF), and the like. The support element  70  can be made from the same or a different material. 
     The cup and support element can be manufactured in any suitable manner. In some embodiments, the cup can be manufactured by machining, injection molding, overmolding, casting, or by one of several additive manufacturing methods, such as stereolithography, fused deposition, or selective sintering. In some embodiments, the support element can be manufactured integrally with the cup. In some embodiments, the support element can be manufactured separately from the cup and affixed within the interior region of the cup in any suitable manner, such as by adhesive, sonic welding, or the like. 
     The tines  14 ,  16  can be made from a material, such as stainless steel, nickel, aluminum, or titanium, or alloys thereof, that provides suitable strength and electrical conductivity. The tip can be made of the same or a different electrically conductive material. The tip can be integral with a body of the tine, or the tip can be attached to the body of the tine in any suitable manner, such as brazing, to facilitate electrical conductivity between the body and the tip and to withstand breakage under typical usage. 
     The forceps can be fabricated in any suitable manner. In one embodiment, an electrically conductive material for the tines is extruded or otherwise provided in sheet form. The sheet can be drawn or rolled to achieve a desired final thickness dimension for the tine bodies. The tines are stamped from the sheet in the desired configuration. If the tips are formed separately from the bodies, the tips are attached to the body, for example, by brazing. Serrations for finger grips, if present, can be stamped into a midportion of the tines to aid a physician in gripping the forceps during use. 
     A rear or spring section can be cold formed, as by rolling, to compress its thickness and to work harden the material. Work hardening of the material in this section strengthens the material, enabling a physician to squeeze the tines together repeatedly to grasp tissue and release the tines to return to their rest position. 
     The perimeter of the strip is stamped to form the general shape of the tine. The tine can have a generally straight configuration, or the tine can have bends along its length (as shown in  FIGS. 2-3 ), depending on the particular application. The perimeter of the tine is formed, as by a coining process, to form the edges. The tab is stamped, deburred, and formed at the proximal end of the tine. The terminal pins can be attached to the tabs in any suitable manner, such as by crimping, welding, or soldering. Apertures can be stamped into the proximal end to allow the potting material to flow through and around the tine. Openings for gripping pads, if present, can be stamped or cut in the tines. 
     The tines with attached terminal pins are inserted through the openings in the cup. The potting material is placed within the cup and cured. 
     Additional aspects include the following:
     1. An electrosurgical forceps comprising:   

     a cup comprising:
         a circumferentially extending wall having an outer surface, an inner surface, and an open distal end,   a proximal end wall extending across a proximal end of the circumferentially extending wall and having an inner surface, at least one opening disposed through the proximal end wall, and   an interior region defined within the inner surface of the circumferentially extending wall and the inner surface of the proximal end wall;       

     a terminal pin disposed in the at least one opening in the proximal end wall, an end portion of the terminal pin extending proximally out of the cup; 
     a pair of tines, each tine being generally elongated and having a tip at a distal end and a proximal end fixed with the cup, one tine of the pair of tines connected for electrical communication to the terminal pin; 
     a support element within the interior region of the cup configured to support at least the one tine of the pair of tines within the cup; and 
     a potting material within the interior region of the cup.
     2. The forceps of embodiment 1, wherein the support element comprises a collar surrounding at least a portion of the proximal end of the one tine.   3. The forceps of embodiment 2, wherein the collar is coaxial with the at least one opening.   4. The forceps of any of embodiments 2-3, wherein the collar has an inner diameter greater than an inner diameter of the at least one opening.   5. The forceps of any of embodiments 2-4, wherein the support element further comprises one or more ribs extending from the collar across the inner surface of the proximal end wall to the inner surface of the circumferentially extending wall.   6. The forceps of any of embodiments 2-5, wherein the support element comprises a second collar surrounding at least a portion of the proximal end of the second tine.   7. The forceps of embodiment 6, wherein the support element further comprises one or more additional ribs extending from the second collar across the inner surface of the proximal end wall to the inner surface of the circumferentially extending wall.   8. The forceps of any of embodiments 6-7, wherein the support element further comprises a connecting rib extending across the inner surface of the proximal end wall between the collar and the second collar.   9. The forceps of any of embodiments 1-8, further comprising a sleeve or crimp member coaxially surrounding the one tine and the terminal pin at least partially within the support element.   10. The forceps of an of embodiments 1-9, further comprising a second opening disposed through the proximal end wall of the cup, a second terminal pin disposed in the second opening in the proximal end wall, an end portion of the second terminal pin extending proximally out of the cup, and a second tine of the pair of tines connected for electrical communication to the second terminal pin; and   

     wherein the support element is configured to support the second tine within the cup.
     11. The forceps of any of embodiments 1-10, wherein the potting material comprises an epoxy.   12. The forceps of any of embodiments 1-11, wherein the circumferentially extending wall is generally cylindrical.   13. A method of forming the electrosurgical forceps of any of embodiments 1-12, comprising:   

     providing the pair of tines and the terminal pin; 
     attaching the one tine of the pair of tines to the terminal pin for electrical communication; 
     mounting the pair of tines and the one terminal pin to the cup with the support element supporting the one tine or both tines of the pair of tines; and 
     filling the cup with a potting material. 
     As used herein, “consisting essentially of” allows the inclusion of materials or steps that do not materially affect the basic and novel characteristics of the claim. Any recitation herein of the term “comprising,” particularly in a description of components of a composition or in a description of elements of a device, can be exchanged with “consisting essentially of” or “consisting of.” 
     It will be appreciated that the various features of the embodiments described herein can be combined in a variety of ways. For example, a feature described in conjunction with one embodiment may be included in another embodiment even if not explicitly described in conjunction with that embodiment. 
     To the extent that the appended claims have been drafted without multiple dependencies, this has been done only to accommodate formal requirements in jurisdictions which do not allow such multiple dependencies. It should be noted that all possible combinations of features which would be implied by rendering the claims multiply dependent are explicitly envisaged and should be considered part of the invention. 
     The present invention has been described in conjunction with certain preferred embodiments. It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials or embodiments shown and described, and that various modifications, substitutions of equivalents, alterations to the compositions, and other changes to the embodiments disclosed herein will be apparent to one of skill in the art.