Abstract:
The invention includes an electromechanical hand-switching forceps arrangement that includes a switch in the form of an insulated pin and an insulated cylinder block to receive the pin midway along the respective tines. The insulated pin and insulated cylinder block contain respective contacts. Except for the contacts themselves, the switch is fully enclosed and fully insulated so that when it is activated, there is no leakage of high frequency electrosurgical current in the surrounding area. The pin is normally disposed just within the opening in the cylinder block such that they are not in contact with the closing of the tips of the tines.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to forceps for use in deep body cavity surgery, and more particularly to a forceps for use in division of tissues of haemostasis in such surgeries.  
       BACKGROUND OF THE INVENTION  
       [0002]     It is a common practice in some surgical techniques to utilize electrical current for the cauterization or electro-coagulation of small blood vessels and the like. While foot switches operated by the surgeon have been used to operate such devices, the shortcomings of this arrangement have led to the development of alternate devices that provide safer and more sophisticated control of the cauterization instrument. For example, in the 1960s, relay operated electrosurgical forceps were developed, such as disclosed in U.S. Pat. No. 3,100,489 to Bagley. In the forceps of Bagley, closure of the forceps itself closes a switching means to provide radio frequency electrical energy to a site to be treated.  
         [0003]     In this type of arrangement, typically, the contacts of the switch on the forceps are exposed to permit engagement thereof when the forceps are closed. Inasmuch as the potentials on these exposed contacts can be substantial, however, there is a certain degree of danger associated therewith. The danger of inadvertently burning unintended tissue is magnified in deep body cavity type surgery, particularly where the surgeon is operating through a relatively small incision. Further, in surgeries where excessive moisture is present, such fluid can cause inadvertent electrical contact and activation of electrical energy.  
         [0004]     In an attempt to remedy these shortcomings, hand-switch operated electrosurgical forceps were developed. Such an arrangement is disclosed, for example in U.S. Pat. No. 4,041,952 to Morrison, Jr. In hand-switch forceps, a switching member is disposed on only one tine of the forceps, and is operated independently of the closing of the forceps. This type of arrangement, however, likewise has its shortcomings. Most notably, the operation of the switching member is sometimes cumbersome. Moreover, it requires the extra step of actuating the switch, rather than the automatic operation upon closure of the forceps.  
         [0005]     As a result, it is desirable to provide an electrosurgical forceps arrangement that overcomes the shortcomings and maintains the advantages associated with the various arrangements known in the art.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     The invention provides an electromechanical forceps arrangement that includes a switch in the form of an insulated pin and an insulated cylinder block to receive the pin midway along the respective tines. The insulated pin and insulated cylinder block contain respective contacts. Except for the contacts themselves, the switch is fully enclosed and fully insulated so that when it is activated, there is no leakage of high frequency electrosurgical current in the surrounding area. The distal end of the pin is normally disposed within the opening in the cylinder block such that they are not in contact with the closing of the tips of the tines. The gap between the contacts is sized such that there is no uninsulated part of the switch that is exposed when the instrument tips are open. As a result, the electrosurgical hand-switching device allows the instrument to be in close proximity to tissue or with the pocket of the surgical site without the danger of burning the surrounding areas around the switch with unintended spark or contact. When the switch contacts are touching each other, however, it activates the flow of high frequency current from an energy source, such as an electrosurgical generator to the surgical site.  
         [0007]     In use, the surgeon brings the tines of the forceps together to touch the tips to the desired surgical site. Additional force is required, however, to bring the midsections of the tines further toward each other in order to touch the switch contacts. Thus, once in such proper position, the surgeon squeezes the central portions of the tines slightly further to cause the uninsulated contact at the distal tip of the pin to engage the second contact at the uninsulated base of the cylinder block to activate electrical current to the tips of the tines.  
         [0008]     In a monopolar application, the instrument comprises an active electrode (+), while the dispersive electrode is remotely attached to the patient body, which is the ground (−). Conversely, in a bipolar application, both poles are contained within the instrument, either tip of the respective tine being the active electrode or the ground. In both monopolar and bipolar application, the switch is attached to the forceps, which is connected to the electrosurgical generator by a cable. Accordingly, the surgeon may remotely and instantaneously activate the electrosurgical generator by closing or touching the switch contacts together.  
         [0009]     The switch contacts can be made from any conductive and biocompatible material. Inasmuch as the device is preferably reusable, the switch insulation or shielding can be any biocompatible material that withstands high frequency electrosurgical voltage at elevated levels, and can be sterilized in any manner of hospital sterilization process.  
         [0010]     These and other objects and advantages of the invention will be apparent to those skilled in the art upon reading the following detailed description and upon reference to the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a side view of a hand-switching forceps assembly constructed in accordance with teachings of the art.  
         [0012]      FIG. 2  is a plan view of the hand-switching forceps of  FIG. 1 , a sleeve being partially broken away.  
         [0013]      FIG. 3  is an enlarged, partial cross-sectional view of the contact switch of the hand-switching forceps of  FIG. 2  in an open position.  
         [0014]      FIG. 4  is an enlarged, partial cross-sectional view of the contact switch of the hand-switching forceps of  FIG. 2  in a closed position.  
         [0015]      FIG. 5  is an exploded view of the contact switch of  FIGS. 3-4 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     Turning now to the drawings, there is shown in  FIGS. 1 and 2 , there is a hand-switching forceps assembly  20  constructed in accordance with teachings of the invention. The forceps assembly  20  includes a surgical forceps  22  having a first tine  24  and a second tine  26  coupled at their proximal ends at a sleeve  28 . The tines  24 ,  26  may be so coupled by any appropriate means. The tines  24 ,  26  are typically formed of stainless steel, nickel-plated brass, titanium, or any composite material with a conductive core. The distal ends of the tines  24 ,  26  present tips  30 ,  32 . When the tines  24 ,  26  are advanced toward one another, the tips  30 ,  32  touch, allowing the surgeon to grasp tissue or another item such as a suture.  
         [0017]     In use, as the tips  30 ,  32  of the forceps  22  are closed around tissue (not shown), electrosurgical current is passed to through the tines  24 ,  26  to the tips  30 ,  32  such that it is applied to the grasped tissue to cauterize or electro-coagulate small blood vessels at a surgical site. Power is typically supplied to the surgical forceps  22  from a power source (not shown) by way of a cable  40  that may be coupled to the power source by ajack or plug or other appropriate fitting arrangement  42 . While the illustrated embodiment includes a two-prong jack  42 , the fitting arrangement  42  could alternately include a three-prong jack, for example, as is known in the industry. The illustrated embodiment comprises a monopolar cable  40  comprising two wires  44 ,  46 . It will be appreciated, however that a bipolar arrangement may alternately be utilized in keeping with the invention. The wires  44 ,  46  are electrically coupled to the respective tines  24 ,  26  such that when the tips  30 ,  32  are closed around the tissue and upon closing of a switching assembly (indicated generally as  48 ), power is supplied to one or both of the tips  30 ,  32 . The arrangement for electrically coupling the wires  44 ,  46  to the tines  24 ,  26  will be explained in greater detail below.  
         [0018]     As may best be seen in  FIG. 2 , the forceps  22  includes primary insulative covers  50 ,  52  which substantially cover the length of the tines  24 ,  26  with the respective tips  30 ,  32  being left uncovered. The insulative covers  50 ,  52  may be formed of any appropriate material. Typically, the insulative covers  50 ,  52  are formed of plastic, rubber or the like. It will be appreciated that such insulation must be biocompatible and withstand the high frequency electrosurgical voltage at elevated levels. Further, if the forceps is to be autoclavible, the insulation must be able to withstand such sterilization processes. While any appropriate method may be utilized to form the covers  50 ,  52 , dip-coating and shrink-wrapping have been found to be particularly useful processes by which the insulative covers  50 ,  52  may be applied to the tines  24 ,  26 .  
         [0019]     In accordance with the invention, the switching assembly  48  is fully enclosed and insulated such that electrosurgical current may be accurately, selectively provided to the surgical site, substantially eliminating undesirable arcing that may result in an unintended spark or flow of power. More specifically, and as shown in more detail in  FIG. 3 , the switch assembly  48  comprises an insulated pin  54  and an insulated cylinder block  56  that contain respective contacts  58 ,  60 . In this way, the connection to supply current to the tips  30 ,  32  of the tines  24 ,  26  is not made until the contacts  58 ,  60  touch to make the electrical connection.  
         [0020]     In a currently preferred embodiment of the invention, the pin  54  comprises an enlarged head  61  and a probe portion  68 . The proximal end  62  of the pin  54 , here, a portion of the head  61 , is preferably received in a first bore  64  in one of the tines  24 , while the cylinder block  56  is received in a bore  66  in the other tine  26 . In this way, the pin  54  and cylinder block  56  extend toward one another between the tines  24 ,  26 , the probe portion  68  of the pin  54  being disposed within the channel  55  of the cylinder block  56  with the contact  58  at the distal end  70  of the pin  54  being spaced slightly apart from the contact  60  at the base  57  of the cylinder block  56  in the free position (see  FIG. 3 ). Preferably, in use, the tips  30 ,  32  of the tines  24 ,  26  may be brought together to grasp the target tissue, and the midsections of the forceps  22  may be squeezed slightly more to bring the tines  24 ,  26  closer together to cause the contacts  58 ,  60  to touch and close the switch  48  (see  FIG. 4 ).  
         [0021]     The switch  48  is connected to the power supply by the wires  44 ,  46 , which are preferably jacketed. As shown in  FIG. 2 , in the illustrated monopolar forceps illustrated, one of the wires  46  is connected directly to the forceps  22  at the tine  26  from which the cylinder block  56  extends. The second wire  44  preferably extends along the inside of the tine  24  then through a second bore  66  in the tine  24  to the outside of the tine  24 . The wire  44  then connects to the proximal end  62  of the pin  54  by soldering or the like, as shown in  FIG. 3 . In this way, as the contacts  58 ,  60  are brought together, as shown in  FIG. 4 , connection is made to supply current to the tips  30 ,  32  of the tines  24 ,  26 .  
         [0022]     According to another important feature of the invention, the switching assembly  48 , and, more particularly, the pin  54  and cylinder block  56  are insulated to prevent inadvertent closing of the switch  48  and supply of current to the tips  30 ,  32 . In the currently preferred embodiment, sleeves  72 ,  74  of insulation are disposed about the wire  44  and the tines  24 ,  26 , with the insulative sleeves  72 ,  74  substantially covering all of pin  54  and cylinder block  56  except the probe portion  68  of the pin  54  and the channel  55  of the cylinder block  56 . While the insulative sleeves  72 ,  74  may be of any appropriate material, in the currently preferred embodiment, a polymeric material such as Kynar is utilized. As with the primary insulative sleeves, the secondary insulative sleeves  72 ,  74  must by formed of a biocompatible material that withstands high frequency electrosurgical voltage at elevated levels, as well as the rigors of autoclaving. Further, while the insulative sleeves  72 ,  74  may be applied in any appropriate manner, in the currently preferred embodiment, the insulative sleeves  72 ,  74  are overwraps that are then heat shrunk to the tines  24 ,  26 . It will be appreciated, however, that alternate materials, arrangements or assembly methods may be utilized within the scope of the present invention.  
         [0023]     Preferably, the forceps  22  may be repeatedly autoclaved or otherwise sterilized for repeated use. Alternately, the forceps assembly  20  may be utilized and discarded thereafter.  
         [0024]     While this invention has been described with an emphasis upon preferred embodiments, variations of the preferred embodiments can be used, and it is intended that the invention can be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications encompassed within the spirit and scope of the invention as defined by the following claims.  
         [0025]     All of the references cited herein, including patents, patent applications, and publications, are hereby incorporated in their entireties by reference.