Abstract:
A bipolar forceps includes first and second shaft members and a housing defining a cavity. An end effector assembly is attached to the shafts and includes first and second jaw members that are movable relative to one another a pivot from a spaced apart position to a position closer to one another. A knife channel is defined within the jaw members and is configured to receive a knife therethrough. A trigger assembly is disposed within the cavity and includes a trigger having a first link pivotably coupled at one end to the trigger and slidingly engaged to a second link at the other end. A second link includes a first end that is slidingly receivable within the first link upon actuation of the trigger through a range of motion and a second end pivotably coupled to a third link which, in turn, couples to the knife. Actuation of the trigger translates the knife through the knife channel through the range of motion.

Description:
BACKGROUND 
       [0001]    1. Background of Related Art 
         [0002]    The present disclosure relates to forceps used for open surgical procedures. More particularly, the present disclosure relates to an open bipolar forceps that is capable of sealing and cutting tissue. 
         [0003]    2. Technical Field 
         [0004]    A hemostat or forceps is a simple plier-like tool which uses mechanical action between its jaws to constrict vessels and is commonly used in open surgical procedures to grasp, dissect and/or clamp tissue. Electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize and/or seal tissue. 
         [0005]    Certain surgical procedures require sealing and cutting blood vessels or vascular tissue. Several journal articles have disclosed methods for sealing small blood vessels using electrosurgery. An article entitled Studies on Coagulation and the Development of an Automatic Computerized Bipolar Coagulator, J. Neurosurg., Volume 75, July 1991, describes a bipolar coagulator which is used to seal small blood vessels. The article states that it is not possible to safely coagulate arteries with a diameter larger than 2 to 2.5 mm. A second article is entitled Automatically Controlled Bipolar Electrocoagulation—“COA-COMP”, Neurosurg. Rev. (1984), pp. 187-190, describes a method for terminating electrosurgical power to the vessel so that charring of the vessel walls can be avoided. 
         [0006]    By utilizing an electrosurgical forceps, a surgeon can either cauterize, coagulate/desiccate, reduce or slow bleeding and/or seal vessels by controlling the intensity, frequency and duration of the electrosurgical energy applied to the tissue. Generally, the electrical configuration of electrosurgical forceps can be categorized in two classifications: 1) monopolar electrosurgical forceps; and 2) bipolar electrosurgical forceps. 
         [0007]    Monopolar forceps utilize one active electrode associated with the clamping end effector and a remote patient return electrode or pad which is typically attached externally to the patient. When the electrosurgical energy is applied, the energy travels from the active electrode, to the surgical site, through the patient and to the return electrode. 
         [0008]    Bipolar electrosurgical forceps utilize two generally opposing electrodes which are disposed on the inner opposing surfaces of the end effectors and which are both electrically coupled to an electrosurgical generator. Each electrode is charged to a different electric potential. Since tissue is a conductor of electrical energy, when the effectors are utilized to grasp tissue therebetween, the electrical energy can be selectively transferred through the tissue to create a tissue seal. Once sealed, a knife may be advanced through the tissue seal to cut the tissue using a knife trigger. 
       SUMMARY 
       [0009]    The present disclosure relates to forceps used for surgical procedures. More particularly, the present disclosure relates to a bipolar forceps for treating tissue that is capable of sealing and cutting tissue. 
         [0010]    As is traditional, the term “distal” refers herein to an end of the apparatus that is farther from an operator, and the term “proximal” refers herein to the end of the electrosurgical forceps that is closer to the operator. 
         [0011]    Aspects of the present disclosure include a bipolar forceps having one or more members and a housing defining a cavity disposed on the one or more shaft members. An end effector assembly is attached the shaft member(s) and includes first and second jaw members that are movable relative to one another a pivot from a spaced apart position to a position closer to one another. A knife channel is defined within the jaw members and is configured to receive a knife therethrough. A trigger assembly is disposed within the cavity and includes a trigger having a first link pivotably coupled at one end to the trigger and slidingly engaged to a second link at the other end. A second link includes a first end that is slidingly receivable within the first link upon actuation of the trigger through a range of motion and a second end pivotably coupled to a third link which, in turn, couples to the knife. Actuation of the trigger translates the knife through the knife channel through the range of motion. 
         [0012]    In one aspect, the first and second links are transitionable through the range of motion of the trigger from an extended configuration wherein the length of the first and second links combines to a first length to a compressed configuration wherein the length of the first and second links combines to a second length. The second length is shorter than the first length. The second link may be telescopically received within the first link or voce versa. 
         [0013]    In other aspects, a biasing member is disposed within one or both of the first and second links and is configured to bias the links in the extended configuration. In yet other aspects, the first and second links transition between the extended and compressed configurations through the range of motion of the trigger during actuation and release. In still other aspects, the first and second links are normal to one another when disposed in the compressed configuration. 
         [0014]    In aspects, the transitioning of the first and second links through the range of motion of the trigger from the extended configuration to the compressed configuration reduces an arc of rotation of the trigger, which, in turn, reduces the necessary size of the cavity. 
         [0015]    In aspects, the pivot defines a longitudinal slot therethrough and the knife is configured to move within the longitudinal slot upon translation thereof. 
         [0016]    The present disclosure also relates to a bipolar forceps including first and second shaft members. One (or both) of the first and second shaft members is configured to support a housing defining a cavity therein. A first jaw member is attached to the first shaft member and a second jaw member attached to the second shaft member. The jaw members are movable relative to one another about a pivot from a spaced apart position to a position closer to one another. One (or both) of the jaw members includes a knife channel defined therein which is configured to receive a knife therethrough. A trigger assembly is disposed within (or partially disposed within) the cavity and includes a trigger having a first link pivotably coupled at one end thereto and slidingly engaged to a second link at the other end thereof. The second link includes a first end that is slidingly receivable within (or at least partially within) the first link (or vice versa) upon actuation of the trigger through a range of motion and a second end that is pivotably coupled to a third link which, in turn, couples to the knife such that actuation of the trigger translates the knife through the knife channel through the range of motion. 
         [0017]    In aspects, the links are transitionable through the range of motion of the trigger from an extended configuration wherein the length of the first and second links combines to a first length to a compressed configuration wherein the length of the first and second links combines to a second length, the second length being shorter than the first length. A biasing member is disposed within at least one of the first and second links and is configured to bias the links in the extended configuration. In aspects, the second link is telescopically received within the first link (or vice versa). 
         [0018]    In other aspects, the first and second links transition between the extended and compressed configurations through the range of motion of the trigger during actuation and release. In yet other aspects, the first and second links are normal to the third link when disposed in the compressed configuration or fully compressed configuration. The transitioning of the first and second links through the range of motion of the trigger from the extended configuration to the compressed configuration reduces an arc of rotation of the trigger, which, in turn, reduces the necessary size of the cavity. 
         [0019]    In still other aspects, the pivot defines a longitudinal slot therethrough and the knife is configured to advance through the longitudinal slot upon translation thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    Various embodiments of the bipolar forceps are described herein with reference to the drawings wherein: 
           [0021]      FIG. 1  is a perspective view of an open electrosurgical forceps according to an embodiment of the present disclosure including a disposable housing, a disposable electrode assembly and a trigger assembly; 
           [0022]      FIG. 2  is internal side view of the forceps of  FIG. 1  with a trigger of the trigger assembly shown in an unactuated position; 
           [0023]      FIG. 3  is internal side view of the forceps of  FIG. 1  with the trigger shown in an actuated position; 
           [0024]      FIG. 4A  is an enlarged, side view of various linkages of the trigger assembly shown in the unactuated position; 
           [0025]      FIG. 4B  is as internal, schematic view of a compression spring of the trigger assembly shown in an extended orientation; 
           [0026]      FIG. 5A  is an enlarged, side view of the various linkages of the trigger assembly shown in a compressed orientation; 
           [0027]      FIG. 5B  is as internal, schematic view of the compression spring of the trigger assembly shown in the compressed orientation; 
           [0028]      FIG. 6A  is an enlarged, side view of the various linkages of the trigger assembly shown in a second extended orientation; 
           [0029]      FIG. 6B  is as internal, schematic view of the compression spring the trigger assembly shown in the second extended orientation; and 
           [0030]      FIG. 7  is a schematic illustration of a robotic surgical system configured for use in conjunction with aspects and features of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    Referring initially to  FIGS. 1-3 , a bipolar forceps  10  for use with open surgical procedures includes a mechanical forceps  20  having an end effector  24  and a disposable electrode assembly  21 . The various mechanisms and features described herein may equally relate to an endoscopic forceps (not shown). Bipolar forceps  20  includes first and second elongated shaft members  12  and  14 . Elongated shaft member  12  includes proximal and distal end portions  13  and  17 , respectively, and elongated shaft member  14  includes proximal and distal end portions  15  and  19 , respectively. Handle members  16  and  18  are disposed at proximal end portions  13 ,  15  of shaft members  12 ,  14 , respectively, and are configured to allow a user to effect movement of at least one of the shaft members  12  and  14  relative to the other. The end effector  24  includes opposing jaw members  42 ,  44  that extend from the distal end portions  17  and  19  of shaft members  12  and  14 , respectively. The jaw members  42 ,  44  are movable relative to each other in response to movement of shaft members  12 ,  14 . 
         [0032]    Shaft members  12  and  14  are affixed to one another about a pivot  25  ( FIG. 2 ) such that movement of shaft members  12 ,  14 , imparts movement of the jaw members  42 ,  44  from an open configuration ( FIG. 2 ) wherein the jaw members  44 ,  42  are disposed in spaced relation relative to one another to a clamping or closed configuration ( FIG. 3 ) wherein the jaw members  42 ,  44  cooperate to grasp tissue therebetween. In embodiments, the forceps  10  may be configured such that movement of one or both of the shaft members  12 ,  14  causes only one of the jaw members to move with respect to the other jaw member. This is particularly noted with respect to endoscopic forceps (not shown) which may include jaw members that move in a unilateral fashion. 
         [0033]    Disposable electrode assembly  21  is configured to releasably couple to mechanical forceps  20  and is operably coupled to a housing  70  having a pair of housing halves configured to matingly engage and releasably encompass at least a portion of shaft member  14 . Disposable electrode assembly  21  includes opposing electrodes  110  and  120  that are configured to releasably couple to respective corresponding jaw members  24  and  21 . Housing  70  also serves to at least partially house a knife  85  having a sharpened distal cutting edge and a knife actuation mechanism or trigger assembly  90  configured to effect advancement of the knife  85  through a knife channel  58  ( FIG. 1 ) defined in one or both electrodes  110 ,  120  to transect tissue, as further detailed below. One or more push buttons  75  is disposed on housing  70  and is accessible to allow a user to actuate the button  75  to release the mechanical coupling of housing  70  and shaft member  14 . 
         [0034]    As shown in  FIGS. 2 and 3 , a pair of wires  61  and  62  are electrically connected to the electrodes  120  and  110 , respectively, and are bundled to form a cable  28  that extends through housing  70  and terminates at a terminal connector  30  configured to mechanically and electrically couple to a suitable energy source, such as an electrosurgical generator (not shown). In embodiments, wire  61  may be configured to extend through an activation switch  50  that, upon actuation thereof, energy is supplied to the electrodes  110  and  120 . Other types of activation switches  50  are also contemplated which, upon actuation thereof, send an electrical signal to the generator to supply energy to the opposing electrodes  110  and  120 . Examples of electrosurgical generators include the LIGASURE® Vessel Sealing Generator and the ForceTriad® Generator sold by Covidien. In some embodiments, a suitable energy source may be a battery (not shown) supported by the housing  70  and electrically connected to the electrodes  110  and  120 . 
         [0035]    As shown in  FIG. 2 , electrode  120  includes an electrically conductive sealing surface  126  configured to conduct electrosurgical energy therethrough and an electrically insulative substrate  121  that serves to electrically insulate sealing surface  126  from jaw member  44 . Electrode  110  includes an electrically conductive sealing surface  116  configured to conduct electrosurgical energy therethrough and an electrically insulative substrate  111  attached thereto. 
         [0036]    While jaw members  42 ,  44  are in an open configuration, the electrodes  120  and  110  may be slid between opposing jaw members  44  and  42  to couple electrodes  120  and  110  with jaw member  44  and  42 , respectively. Housing  70  may then be coupled about at least a portion of shaft member  14 . 
         [0037]    To electrically control the end effector  24 , activation button  50  is operable by a user to initiate and terminate the delivery of electrosurgical energy to end effector  24 . During use, depressing activation button  50  initiates the delivery of electrosurgical energy to the opposing electrodes  110 ,  120  of the end effector  24  to effect a tissue seal. In some embodiments, delivery of electrosurgical energy to end effector  24  may also be terminated by the electrosurgical generator based on any suitable parameters, e.g., sensed tissue properties, time parameters, sensed energy properties, etc. 
         [0038]    Once a tissue seal is established, the knife  85  may be advanced through the knife channel  58  to transect the sealed tissue, as detailed below. However, in some embodiments, knife  85  may be advanced through the knife channel  58  before, during, or after tissue sealing. In some embodiments, a knife lockout mechanism (not shown) is provided to prevent extension of the knife  85  into the knife channel  58  when the jaw members  42 ,  44  are in the open configuration, thus preventing accidental or premature transection of tissue, as described below. 
         [0039]    With reference to  FIGS. 3-6B , the knife actuation mechanism or trigger assembly  90  is operably associated with a trigger  45  ( FIG. 1 ) having opposing trigger handles  45   a ,  45   b  extending from opposing sides of housing  70 . Upon actuation of trigger handles  45   a ,  45   b , the trigger assembly  90  responds utilizing a series of inter-cooperating elements to actuate the knife  85  through the knife channel  58  to sever tissue grasped between jaw members  42 ,  44 . The trigger assembly  90  includes a first link  92  that couples to the trigger handles  45   a  and  45   b  via pivot  92   a . A second link  93  is slidingly or telescopically received within link  92  (or vice versa) and is movable from a compressed configuration to an extended configuration. A biasing member or spring  97  biases the two links  92  and  93  in the extended configuration. A third link  94  is coupled to an opposite end of link  93  via pivot  93   a , which, in turn, couples to a fourth link  95  via pivot  94   a  that ultimately connects to the knife  85  via link  96 . Link  96  connects to the knife  85  via pivot  95   a.    
         [0040]    As best shown in  FIGS. 4A, 5A and 6A  which depict the sequential movement of the various links of the trigger assembly  90  upon movement of the trigger  45  to deploy the knife  85  to cut tissue, links  92  and  93  allow the trigger assembly  90  to rotate around a reduced arc while advancing the knife  85 . More particularly, as mentioned above, link  92  is dimensioned to slidingly receive link  93  (or vice versa). In a first unactuated position, links  92  and  93  are extended to a length X1 due to the bias of the spring  97  between links  92  and  93  and a minimum angle is disposed between links  92 ,  93  (in combination) and link  94 . A compression rail  91  serves to reduce movement of the inter-cooperating links  92 ,  93  during actuation. Upon rotation of the trigger  45  towards a 90 degree angle, link  93  slides within link  92  against the bias of spring  97  to a compressed configuration having a length X2. This reduces the arc of rotation of the two links  92  and  93  which allows for the design of a smaller housing  70 , i.e., the length X2 is also the maximum allowable distance between pivot  92   a  and compression rail  91 . The two links  92  and  93  are normal to the fourth link  94  when disposed in a fully compressed configuration. Continued rotation of the trigger  45  towards a greater than 90 degrees angle works to advance the knife  85  while the two links  92  and  93  are urged back towards an extended configuration having a length X1 under the bias of spring  97 . 
         [0041]    A biasing member (e.g., a torsion spring not shown) may be disposed between the first link  92  and the handle member  45  which is operably coupled at one end to a portion of the first link  92  and at the other end to a suitable mechanical interface within the housing  70  that stabilizes the biasing member during use of the knife trigger assembly  90 . The biasing member serves to bias the trigger  45  such that subsequent to actuation of the knife  85  through the knife channel  58 , handle member  45  is biased to return to an unactuated position thereby retracting the knife  85  proximally. 
         [0042]    With reference to  FIG. 2 , pivot  25  defines a longitudinal passageway  27  therebetween to allow the knife  85  to reciprocate therethrough. Movement of shaft members  12 ,  14  relative to each other causes rotational movement of pivot  25  and the passageway  27  from a first position wherein the jaw members  42  and  44  are spaced relative to one another and knife  85  is prevented from passing therethrough to a second position wherein the jaw members  42  and  44  are closer to one another and the knife  85  is free to pass therethrough. 
         [0043]    A knife guide (not shown) may be supported within the housing  70  between the end effector  24  and the trigger assembly  90  and extends through passageway  27 . Knife guide may include one or more suitable mechanical features (e.g., protrusions) that interface with corresponding suitable mechanical features disposed on shaft member  14  to provide location control, e.g., lateral support, to the knife  85  during translation thereof thereby ensuring proper alignment of the knife  85  as the knife  85  enters the knife channel  58  defined in electrodes  110 ,  120 . 
         [0044]    The tissue seal thickness and tissue seal effectiveness may be influenced by the pressure applied to tissue between jaw members  44 ,  42  and the gap distance between the opposing electrodes  110  and  120  ( FIG. 5 ) during tissue sealing. In the second, closed position, a separation or gap distance “G” may be maintained between the sealing surfaces  116 ,  126  by one or more stop members  56  disposed on one or both of sealing surfaces  116 ,  126 . The stop members  56  contact the sealing surface on the opposing jaw member and prohibit further approximation of the sealing surfaces  116 ,  126 . In some embodiments, to provide an effective tissue seal, an appropriate gap distance of about 0.001 inches to about 0.010 inches and, desirably, between about 0.002 and about 0.006 inches may be provided. In some embodiments, the stop members  56  are constructed of an electrically non-conductive plastic or other material molded onto the sealing surfaces  116 ,  126 , e.g., by a process such as overmolding or injection molding. In other embodiments, the stop members  56  are constructed of a heat-resistant ceramic deposited onto sealing surfaces  116 ,  126 . 
         [0045]    As mentioned above, the jaw members  42 ,  44  may be moved from the open configuration of  FIGS. 1 and 2  to the closed configuration depicted in  FIG. 3 . As the shaft members  12 ,  14  pivot about pivot  25 , shaft member  12  engages activation button  50  to initiate delivery of electrosurgical energy to end effector  24  to seal tissue between the jaw members  42  and  44 . Once tissue is sealed, handle  45  may be selectively actuated to advance the knife  85  distally through knife channel  58 . More specifically, as handle  45  rotates in the general proximal direction, the first and second links  92 ,  93  impart a rotational force on third link  94 , thereby causing third link  94  to rotate about pivot pin  93   a  causing fourth link  95  to translate distally to advance knife  85  into the knife channel  58 . 
         [0046]    As indicated above, the initial position of the handle  45  is actively maintained by the influence of a biasing member (not shown) on the trigger  45 . Moreover, the rotational arc of the combination of links  92 ,  93  and  94  is reduced by virtue of the sliding relationship of links  92  and  93  during actuation. This reduces the size of the housing  70  need to support the actuation mechanism  90 . 
         [0047]    The above-detailed aspects and features of the present disclosure may be configured to work with robotic surgical systems and what is commonly referred to as “Telesurgery.” Such systems employ various robotic elements to assist the surgeon and allow remote operation (or partial remote operation) of surgical instrumentation. Various robotic arms, gears, cams, pulleys, electric and mechanical motors, etc. may be employed for this purpose and may be designed with a robotic surgical system to assist the surgeon during the course of an operation or treatment. Such robotic systems may include remotely steerable systems, automatically flexible surgical systems, remotely flexible surgical systems, remotely articulating surgical systems, wireless surgical systems, modular or selectively configurable remotely operated surgical systems, etc. 
         [0048]    The robotic surgical systems may be employed with one or more consoles that are next to the operating theater or located in a remote location. In this instance, one team of surgeons or nurses may prep the patient for surgery and configure the robotic surgical system with one or more of the instruments disclosed herein while another surgeon (or group of surgeons) remotely control the instruments via the robotic surgical system. As can be appreciated, a highly skilled surgeon may perform multiple operations in multiple locations without leaving his/her remote console which can be both economically advantageous and a benefit to the patient or a series of patients. 
         [0049]    The robotic arms of the surgical system are typically coupled to a pair of master handles by a controller. The handles can be moved by the surgeon to produce a corresponding movement of the working ends of any type of surgical instrument (e.g., end effectors, graspers, knifes, scissors, etc.) which may complement the use of one or more of the embodiments described herein. The movement of the master handles may be scaled so that the working ends have a corresponding movement that is different, smaller or larger, than the movement performed by the operating hands of the surgeon. The scale factor or gearing ratio may be adjustable so that the operator can control the resolution of the working ends of the surgical instrument(s). 
         [0050]    The master handles may include various sensors to provide feedback to the surgeon relating to various tissue parameters or conditions, e.g., tissue resistance due to manipulation, cutting or otherwise treating, pressure by the instrument onto the tissue, tissue temperature, tissue impedance, etc. As can be appreciated, such sensors provide the surgeon with enhanced tactile feedback simulating actual operating conditions. The master handles may also include a variety of different actuators for delicate tissue manipulation or treatment further enhancing the surgeon&#39;s ability to mimic actual operating conditions. 
         [0051]    Turning to  FIG. 7 , a medical work station is shown generally as work station  1000  and generally may include a plurality of robot arms  1002 ,  1003 ; a control device  1004 ; and an operating console  1005  coupled with control device  1004 . Operating console  1005  may include a display device  1006 , which may be set up in particular to display three-dimensional images; and manual input devices  1007 ,  1008 , by means of which a surgeon may be able to telemanipulate robot arms  1002 ,  1003  in a first operating mode. 
         [0052]    Each of the robot arms  1002 ,  1003  may include a plurality of members, which are connected through joints, and an attaching device  1009 ,  1011 , to which may be attached, for example, a surgical tool “ST” supporting an end effector  1100 , in accordance with any one of several embodiments disclosed herein, as will be described in greater detail below. 
         [0053]    Robot arms  1002 ,  1003  may be driven by electric drives (not shown) that are connected to control device  1004 . Control device  1004  (e.g., a computer) may be set up to activate the drives, in particular by means of a computer program, in such a way that robot arms  1002 ,  1003 , their attaching devices  1009 ,  1011  and thus the surgical tool (including end effector  1100 ) execute a desired movement according to a movement defined by means of manual input devices  1007 ,  1008 . Control device  1004  may also be set up in such a way that it regulates the movement of robot arms  1002 ,  1003  and/or of the drives. 
         [0054]    Medical work station  1000  may be configured for use on a patient  1013  lying on a patient table  1012  to be treated in a minimally invasive manner by means of end effector  1100 . Medical work station  1000  may also include more than two robot arms  1002 ,  1003 , the additional robot arms likewise being connected to control device  1004  and being telemanipulatable by means of operating console  1005 . A medical instrument or surgical tool (including an end effector  1100 ) may also be attached to the additional robot arm. Medical work station  1000  may include a database  1014 , in particular coupled to with control device  1004 , in which are stored, for example, pre-operative data from patient/living being  1013  and/or anatomical atlases. 
         [0055]    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 examples of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 
         [0056]    Although the foregoing disclosure has been described in some detail by way of illustration and example, for purposes of clarity or understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the appended claims.