Patent Publication Number: US-11638605-B2

Title: Compact jaw including split pivot pin

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/811,451, filed Jul. 28, 2015, now U.S. Pat. No. 10,709,494, which is a continuation of U.S. patent application Ser. No. 13/933,409, filed Jul. 2, 2013, now U.S. Pat. No. 9,113,609, which is a continuation of U.S. patent application Ser. No. 12/692,414, filed on Jan. 22, 2010, now U.S. Pat. No. 8,480,671, the entire contents of each of which are incorporated by reference herein. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to an apparatus for performing an endoscopic electrosurgical procedure. More particularly, the present disclosure relates to an apparatus for performing an endoscopic electrosurgical procedure that employs an endoscopic electrosurgical apparatus that includes an end effector assembly configured for use with variously-sized access ports. 
     Description of Related Art 
     Electrosurgical apparatuses (e.g., electrosurgical forceps) are well known in the medical arts and typically include a handle, a shaft and an end effector assembly operatively coupled to a distal end of the shaft that is configured to manipulate tissue (e.g., grasp and seal tissue). Electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect homeostasis by heating the tissue and blood vessels to coagulate, cauterize, fuse, seal, cut, desiccate, and/or fulgurate tissue. 
     As an alternative to open electrosurgical forceps for use with open surgical procedures, many modern surgeons use endoscopes and endoscopic electrosurgical apparatus (e.g., endoscopic forceps) for remotely accessing organs through smaller, puncture-like incisions. As a direct result thereof, patients tend to benefit from less scarring, less pain, and reduced healing time. Typically, the endoscopic forceps are inserted into the patient through one or more various types of cannulas or access ports (typically having an opening that ranges from about five millimeters to about fifteen millimeters) that has been made with a trocar; as can be appreciated, smaller cannulas are usually preferred. 
     Endoscopic forceps that are configured for use with small cannulas (e.g., cannulas less than five millimeters) may present design challenges for a manufacturer of endoscopic instruments. 
     SUMMARY 
     Accordingly, an end effector assembly for use with a forceps includes a pair of jaw members, a knife assembly, and one or more cam assemblies. One or both of the jaw members are moveable relative to the other about a pivot between an open position and a closed position for grasping tissue. One or both of the jaw members include a knife channel defined therein that extends therealong. In embodiments, one or both jaw members are adapted to connect to an electrosurgical energy source to electrosurgically treat tissue. The pivot has first and second sections defining a passage therebetween. 
     The knife assembly includes a knife blade and an actuation shaft. The knife blade may be affixed to a distal end of the actuation shaft. The knife blade is disposed distally relative to the pivot. The actuation shaft is configured for slidable translation through the passage defined between the first and second sections of the pivot to allow selective advancement of the knife blade through the knife channel. 
     The one or more cam assemblies are operably coupled to the one or more moveable jaw members and are actuatable to move one or both jaw members between the open and the closed position for grasping tissue therebetween. The one or more cam assemblies include an actuator configured to move each movable jaw member between the open and the closed position upon selective longitudinal translation thereof. The actuator may be moveable to actuate both jaw members. The actuator includes one or more cam pins extending therefrom. One or both jaw members define one or more cam slots therein such that the one or more cam slots and the one or more cam pins are configured to cooperate with one another to move each moveable jaw member. An actuator tube is operably associated with the forceps which is configured to longitudinally translate the actuator and permit the slidable translation of the actuation shaft therethrough. In one embodiment, a roll joint is operably coupled to the actuator tube and is configured to facilitate rotational movement of the jaw members. 
     The end effector assembly includes a knife tube mounted to the pivot wherein the one or more cam pins are configured to slidably engage the knife tube upon the selective longitudinal translation of the actuator. The knife tube defines a recess adapted to mount each of the first and second sections of the pivot at the distal ends thereof. The distal ends of each of the first and second sections define a profile configured to engage the recess. 
     According to another aspect, a forceps includes a housing, a pair of jaw members, a knife assembly, and one or more cam assemblies. The housing has a shaft that extends therefrom that includes a clevis at a distal end thereof. The shaft of the housing includes an actuator tube. 
     The pair of jaw members are mounted to the clevis about a pivot. One or both jaw members are moveable relative to the other about the pivot between an open position and a closed position for grasping tissue. One or both of the jaw members include a knife channel defined therein that extends therealong. One or both of the jaw members may be adapted to connect to an electrosurgical energy source to electrosurgically treat tissue. The pivot has first and second sections defining a passage therebetween. In embodiments, the first and second sections of the pivot are fixedly connected to the clevis. 
     The knife assembly includes a knife blade and an actuation shaft. The knife blade may be affixed to a distal end of the actuation shaft. The knife blade is disposed distally relative to the pivot. The actuation shaft is configured for slidable translation through the passage defined between the first and second sections of the pivot to allow selective advancement of the knife blade through the knife channel. 
     The one or more cam assemblies are operably coupled to each moveable jaw member and are actuatable to move one or both jaw members between the open and the closed position for grasping tissue therebetween. One or more cam assemblies include an actuator operably coupled to the housing that is configured to move one or both jaw members between the open and the closed position upon selective longitudinal translation thereof. The actuator may be moveable to actuate both jaw members. The actuator includes one or more cam pins extending therefrom. One or both jaw members define one or more cam slots therein such that the one or more cam slots and the one or more cam pins are configured to cooperate with one another to move each moveable jaw member. The actuator tube is configured to longitudinally translate the actuator and permit the slidable translation of the actuation shaft therethrough. 
     The forceps includes a knife tube mounted to the pivot. The one or more cam pins are configured to slidably engage the knife tube upon the selective longitudinal translation of the actuator. The knife tube defines a recess adapted to mount each of the first and second sections of the pivot at the distal ends thereof. The distal ends of each of the first and second sections define a profile configured to engage the recess. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of the present disclosure will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings in which: 
         FIG.  1 A  is a top, perspective view of an endoscopic forceps shown in an open configuration and including a housing, a handle assembly, a shaft and an end effector assembly according to the present disclosure; 
         FIG.  1 B  is a top, perspective view of the endoscopic forceps of  FIG.  1 A  showing the end effector assembly in a closed configuration according to the present disclosure; 
         FIG.  2 A  is an enlarged, top view of the forceps of  FIG.  1 A  showing the disposition of the internal components when the forceps is in an open configuration; 
         FIG.  2 B  is an enlarged, top view of the forceps of  FIG.  1 B  showing the disposition of the internal components when the forceps is in a closed configuration; 
         FIG.  3 A  is an enlarged, top view showing the knife actuator after actuation; 
         FIG.  3 B  is a greatly-enlarged, side cross sectional view of the end effector assembly showing the position of the knife after actuation; 
         FIG.  4 A  is a greatly-enlarged, perspective view of the bottom jaw of the end effector assembly with parts separated; 
         FIG.  4 B  is a greatly-enlarged, perspective view of the top jaw of the end effector assembly with parts separated; 
         FIG.  5    is a greatly-enlarged, perspective view of the elongated shaft for housing various moving parts of the drive assembly and knife assembly; 
         FIG.  6    is a partially exploded, perspective view of the end effector assembly; 
         FIG.  7    is a top view of the end effector assembly with the upper jaw member removed; 
         FIG.  8    is a rear, perspective view of one of the jaw members in accordance with an alternate embodiment of the present disclosure; 
         FIG.  9    is right, rear, perspective view of an end effector assembly shown in a first position according to one embodiment of the present disclosure; 
         FIG.  10    is a left, perspective view of the end effector assembly of  FIG.  9    with the top jaw thereof removed for clarity and with a clevis thereof shown in phantom; 
         FIG.  11    is a right, perspective view of  FIG.  10    with a proximal portion of the bottom jaw removed for clarity; 
         FIG.  12    is a right, perspective view of  FIG.  11    illustrating a second position of the end effector assembly of  FIG.  9   ; and 
         FIG.  13    is a right, perspective view of one embodiment of an end effector assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Detailed embodiments of the present disclosure are disclosed herein; however, the disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. 
     As noted above, it may prove useful in the arts to provide an electrosurgical apparatus that is suitable for use with various access ports, including but not limited to those that are greater than and/or less than five millimeters. With this purpose in mind, the present disclosure includes an electrosurgical forceps that includes a drive assembly operatively coupled to one or more jaw members associated with the end effector assembly of the electrosurgical forceps. The drive assembly is configured to move the jaw members from an open to a closed configuration such that when actuated, the jaw members form a closed loop electrical circuit such that a desired tissue effect (e.g., tissue seal) may be achieved. 
     Turning now to  FIGS.  1 A and  1 B , one embodiment of an electrosurgical forceps  10  is shown for use with various surgical procedures and generally includes a housing  20 , a handle assembly  30 , a rotating assembly  80 , a knife trigger assembly  70  and an end effector assembly  100  which mutually cooperate to grasp, seal and divide tubular vessels and vascular tissue. Although the majority of the figure drawings depict a forceps  10  for use in connection with endoscopic or laparoscopic surgical procedures, the present disclosure may be used for more traditional open surgical procedures. For the purposes herein, the forceps  10  is described in terms of an endoscopic or laparoscopic instrument; however, it is contemplated that an open version of the forceps may also include the same or similar operating components and features as described below. 
     Forceps  10  includes a shaft  12  that has a distal end  16  dimensioned to mechanically engage the end effector assembly  100  and a proximal end  14  that mechanically engages the housing  20 . Details of how the shaft  12  connects to the end effector assembly  100  are described in more detail below. The proximal end  14  of shaft  12  is received within the housing  20  and the connections relating thereto are also described in detail below. In the drawings and in the descriptions that follow, the term “proximal”, as is traditional, will refer to the end of the forceps  10  that is closer to the user, while the term “distal” will refer to the end that is farther from the user. 
     Forceps  10  also includes an electrosurgical cable  310  that may be internally divided into two or more leads which may connect the forceps  10  to a source of electrosurgical energy, e.g., a generator. Generators such as those sold by Covidien, located in Boulder, Colo. may be used as a source of both bipolar electrosurgical energy for sealing vessel and vascular tissues as well as monopolar electrosurgical energy which is typically employed to coagulate or cauterize tissue. It is envisioned that the generator may include various safety and performance features including isolated output, impedance control and/or independent activation of accessories. 
     Handle assembly  30  includes two movable handles  30   a  and  30   b  disposed on opposite sides of housing  20 . Handles  30   a  and  30   b  are movable relative to one another to actuate the end effector assembly  100  as explained in more detail below with respect to the operation of the forceps  10 . 
     Rotating assembly  80  is mechanically coupled to housing  20  and is rotatable approximately 90 degrees in either direction about a longitudinal axis “A.” Rotating assembly  80 , when rotated, rotates shaft  12 , which, in turn, rotates end effector assembly  100 . Such a configuration allows end effector assembly  100  to be rotated approximately 90 degrees in either direction with respect to housing  20 . 
     As mentioned above, end effector assembly  100  is attached at the distal end  16  of shaft  12  and includes a pair of opposing jaw members  110  and  120  (see  FIG.  6   ). Handles  30   a  and  30   b  of handle assembly  30  ultimately connect to drive assembly  60  (see  FIG.  2 A ) which, together, mechanically cooperate to impart movement of the jaw members  110  and  120  from a first, open position wherein the jaw members  110  and  120  are disposed in spaced relation relative to one another, to a second, clamping or closed position wherein the jaw members  110  and  120  cooperate to grasp tissue therebetween. 
     Turning now to the more detailed features of the present disclosure as described with respect to  FIGS.  1 A- 8   , handles  30   a  and  30   b  each include an aperture  33   a  and  33   b , respectively, defined therein which enables a user to grasp and move each respective handle  30   a  and  30   b  relative to one another. Handles  30   a  and  30   b  also include ergonomically-enhanced gripping elements  39   a  and  39   b , respectively, disposed along an outer edge thereof which are designed to facilitate gripping of the handles  30   a  and  30   b  during activation. It is envisioned that gripping elements  39   a  and  39   b  may include one or more protuberances, scallops and/or ribs to enhance gripping. 
     As best illustrated in  FIG.  1 A , handles  30   a  and  30   b  are configured to extend outwardly on opposite sides from a transverse axis “B” defined through housing  20  which is perpendicular to longitudinal axis “A”. Handles  30   a  and  30   b  are movable relative to one another in a direction parallel to axis “B” to open and close the jaw members  110  and  120  as needed during surgery. Details relating to the inner-working components of forceps  10  are disclosed in commonly-owned U.S. patent application Ser. No. 11/540,335. This forceps style is commonly referred to as an “in-line” or hemostat style forceps. In-line hemostats or forceps are more commonly manufactured for open surgical procedures and typically include a pair of shafts having integrally coupled handles which are movable relative to one another to open and close the jaw members disposed at the distal end thereof. 
     As best seen in  FIGS.  2 A and  2 B , the distal end of each handle  30   a  and  30   b  is selectively moveable about pivot pins  34   a  and  34   b  attached to a distal end  21  of the housing  20  to actuate the jaw members  110  and  120 . Movement of the handles  30   a  and  30   b  away from one another (and the housing  20 ) unlocks and opens the handles  30   a  and  30   b  and, in turn, the jaw members  110  and  120  for subsequent grasping or re-grasping of tissue. In one embodiment, the handles  30   a  and  30   b  may be biased in an open configuration to facilitate handling and manipulation of the jaws within an operative field. Various spring-like mechanisms are contemplated which may be utilized to accomplish this purpose. 
     Movable handles  30   a  and  30   b  are designed to provide a distinct lever-like mechanical advantage over conventional handle assemblies. The enhanced mechanical advantage for actuating the jaw members  110  and  120  is gained by virtue of the unique position and combination of several inter-cooperating elements which reduce the overall user forces necessary to obtain and maintain the jaw members  110  and  120  under ideal operating pressures of about 3 kg/cm2 to about 16 kg/cm2. Details relating to the working components the handle assembly and drive assembly are disclosed in above-mentioned U.S. patent application Ser. No. 11/540,335. In other words, it is envisioned that the combination of these elements and their positions relative to one another enables the user to gain lever-like mechanical advantage to actuate the jaw members  110  and  120  enabling the user to close the jaw members  110  and  120  with lesser force while still generating the required forces necessary to effect a proper and effective tissue seal. 
     As shown best in  FIGS.  4 A,  4 B,  5  and  6   , the end effector assembly  100  is designed as a bilateral assembly, i.e., both jaw members  110  and  120  pivot relative to one another about a pivot pin  185  disposed therethrough. A unilateral end effector assembly is also envisioned. End effector assembly  100  further includes a knife guide  133  that houses the knife blade  190  for translation therethrough. Knife guide  133  is assembled with flanges  113  and  123  to allow pivotable movement of the flanges  113  and  123  about a pivot pin  185  disposed between the jaw members  110  and  120  upon translation of a drive pin  180  as explained in more detail below. 
     More particularly, jaw members  110  and  120  include proximal flanges  113  and  123 , respectively, which each include an elongated angled slot  181   a  and  181   b , respectively, defined therethrough. Drive pin  180  mounts jaw members  110  and  120  and knife guide  133  to the end of a rotating shaft  18  and within a cavity  17 ′ defined at the distal ends  17   a  and  17   b  of drive actuator or sleeve  17  (See  FIG.  5   ). Knife guide  133  includes an elongated slot  181   c  defined therethrough, configured for accepting the drive pin  180  and for allowing translation of the drive pin  180  within slots  181   a - 181   c , which pivots the jaw members  110  and  120  relative to one another for grasping tissue. Knife guide  133  may also provide a unique safety feature for the forceps  10  as described in more detail below. 
     Upon actuation of the drive assembly  60 , the drive sleeve  17  reciprocates which, in turn, causes the drive pin  180  to ride within slots  181   a  and  181   b  to open and close the jaw members  110  and  120  as desired and similarly causes the drive pin  180  to ride within slot  181   c  of knife guide  133 . The jaw members  110  and  120 , in turn, pivot about pivot pin  185  disposed through respective pivot holes  186   a  and  186   b  defined within flanges  113  and  123 , the jaw members  110  and  120  and hole  186   c  disposed within knife guide  133 . Upon actuation, knife guide  133  remains oriented in alignment with the shaft  12  as the jaws move about pivot pin  185  (See  FIG.  6   ). As can be appreciated, squeezing handles  30   a  and  30   b  toward the housing  20  pulls drive sleeve  17  and drive pin  180  proximally to close the jaw members  110  and  120  about tissue grasped therebetween and pushing the sleeve  17  distally opens the jaw members  110  and  120  for grasping purposes. 
     Flanges  113  and  123  of j aw members  110  and  120 , respectively, are positioned in an abutting relationship with one another and knife guide  133  is positioned adjacent to flanges  113  and  123 . Flanges  113 ,  123  and knife guide  133  are assembled and engaged via pivot pin  185  disposed through apertures  186   a ,  186   b , and  186   c , respectively. Further, flanges  113 ,  123  are pivotable about one another via drive pin  180  disposed through slots  181   a  and  181   b  of flanges  113 ,  123 , respectively. A knife path  138  may be defined between flange  113  and knife guide  133 , as shown in  FIGS.  6  and  7   . The knife path  138  longitudinally aligns with knife channels  115   a  and  115   b  defined within jaw members  110  and  120 , such that knife blade  190  travels in a substantially straight path through knife path  138  and, further, through knife channels  115   a  and  115   b.    
     Alternatively, the orientation of flanges  113  and  123  may be reversed, with knife path  138  being defined between flange  123  and blade guide  133 . In contrast to prior known designs, the abutting relationship between flanges  113  and  123  (in either orientation) strengthens the jaw flanges  113  and  123  since a blade path or blade channel does not need to be defined therebetween but, rather, is defined on an exterior side of one of the flanges  113  and  123 . Thus, the knife  190  travels between the blade guide  133  and the flanges  113  and  123  and not between flanges. By manufacturing the knife path  138  on either side of the flanges  113  and  123 , jaw splay may also be more easily controlled and tighter tolerances may be employed during the manufacturing process, thereby allowing tighter tolerances on certain features of the jaw member  110  and  120  resulting in better overall performance. 
     For example, the knife channels  115   a  and  115   b  defined within the jaw members  110  and  120 , respectively, may be more precisely aligned with less splay between the jaw members  110  and  120 , thereby facilitating knife blade  190  translation. Moreover, the strength of the flanges  113  and  123  is enhanced as well as the union therebetween, e.g., flat-on-flat abutting flange surfaces have more surface contact making the union therebetween stronger. The knife guide  133  may also be configured to pre-load jaw members  110  and  120  to help ensure proper alignment of knife channel halves  115   a  and  115   b  upon closing of the jaw members  110  and  120  as explained in more detail below. 
     As best shown in  FIG.  6   , blade guide  133  may include a blade stop or hook  135  disposed at a distal end thereof. The blade stop  135  may be integrally associated with the knife guide  133  ( FIG.  6   ), the purpose of which is explained immediately below, or pivotably engaged with the knife guide  133 , the purpose of which is explained with reference to  FIG.  9   . The relationship between flanges  113  and  123  and blade guide  133  is established by pivot pin  185  disposed through apertures  186   a ,  186   b , and  186   c , respectively, and by drive pin  180  disposed through slots  181   a ,  181   b  and  181   c , respectively. Accordingly, when jaw members  110 ,  120  are in a first, or open, position, knife guide  133  pivots such the blade stop  135  interferes with the knife path  138 , thereby preventing distal translation of knife blade  190 . In one embodiment, this may be accomplished by the knife guide  133  including an elongated slot  181   c  that is cammed when the drive pin  180  is biased in a distal-most position such that the knife guide  133  and blade stop  135  pivot thereby obstructing the knife path  138 . 
     When handles  30   a  and  30   b  are squeezed toward the housing  20 , drive sleeve  17  and drive pin  180  are pulled proximally to close the jaw members  110  and  120 , which also pivots the knife guide  133  so that the blade stop  135  no longer obstructs or interferes with the knife path  138 . Thus, in this embodiment, the knife guide  133 , by virtue of the blade stop  135 , prevents distal advancement of knife blade  190  when jaw members  110  and  120  are in the first, open position and permits distal advancement of knife blade  190  when jaw members  110  and  120  are in the second, closed position. 
     Alternatively, a hook (not shown) may be disposed on either of flanges  113  or  123 . The hook would operate in substantially the same manner as the blade stop  135  disposed on the blade guide  133  in the embodiment discussed above. Accordingly, as jaw members  110 ,  120  are opened, the hook on flange  113  or  123  is pivoted into the path of knife blade  190 , thereby preventing distal translation of knife blade  190 . When handles  30   a  and  30   b  are squeezed toward the housing  20 , drive sleeve  17  and drive pin  180  are pulled proximally to close the jaw members  110  and  120 . The pulling of drive pin  180  also pivots flanges  113  and  123 , thereby closing the jaw members  110  and  120  and as a result, the hook is pivoted out of the path of knife blade  190 . 
     As best shown in  FIG.  4 B , jaw member  110  also includes a support base  119  that extends distally from flange  113  and that is configured to support an insulative plate  119 ′ thereon. Insulative plate  119 ′, in turn, is configured to support an electrically conductive tissue engaging surface or sealing plate  112  thereon. Sealing plate  112  may be affixed atop the insulative plate  119 ′ and support base  119  in any suitable manner, e.g., snap-fit, over-molding, stamping, ultrasonically welded, etc. Support base  119  together with the insulative plate  119 ′ and electrically conductive tissue engaging surface  112  are encapsulated by an outer insulative housing  114 . Outer housing  114  includes a cavity  114   a  that is dimensioned to securely engage the electrically conductive sealing surface  112  as well as the support base  119  and insulative plate  119 ′. This may be accomplished by stamping, by overmolding, by overmolding a stamped electrically conductive sealing plate and/or by overmolding a metal injection molded seal plate. All of these manufacturing techniques produce jaw member  110  having an electrically conductive surface  112  that is substantially surrounded by an insulating substrate  114 . 
     The electrically conductive surface or sealing plate  112  and the outer housing  114 , when assembled, form longitudinally-oriented knife channel  115   a  defined therethrough for reciprocation of the knife blade  190 . It is envisioned that the knife channel  115   a  cooperates with corresponding knife channel  115   b  defined in jaw member  120  to facilitate longitudinal extension of the knife blade  190  along a preferred cutting plane to effectively and accurately separate the tissue along the formed tissue seal. As discussed above, when knife blade  190  is deployed, at least a portion of knife blade  190  advances through knife path  138  and into knife channels  115   a  and  115   b . In addition to the blade stop  135 , handle  30   a  may includes a lockout flange (not shown) which prevents actuation of the knife assembly  70  when the handle  30   a  is open thus preventing accidental or premature activation of the knife blade  190  through the tissue. A more detailed discussion of the lockout flange is discussed in above-mentioned U.S. patent application Ser. No. 11/540,335. 
     As explained above and as illustrated in  FIGS.  4 A and  4 B , in one embodiment, the knife channel  115  is formed when the jaw members  110  and  120  are closed. In other words, the knife channel  115  includes two knife channel halves—knife channel half  115   a  disposed in sealing plate  112  of jaw member  110  and knife channel half  115   b  disposed sealing plate  122  of jaw member  120 . It is envisioned that the knife channel  115  may be configured as a straight slot with no degree of curvature which, in turn, causes the blade  190  to move through the tissue in a substantially straight fashion. Alternatively, and as shown, the knife channel  115  may be curved, which has certain surgical advantages. In the particular embodiment shown in  FIGS.  6  and  7   , the knife channel  115  (knife channel  115   a  shown) is curved and is offset from the centerline or longitudinal axis “A” of the forceps  10  by a distance “X” (See  FIGS.  7  and  8   ). This offset distance “X” may be in the range of about 0.010 inches to about 0.040 inches. 
     The offset orientation of the knife blade  190  (by virtue or the knife guide  133  being assembled on one side of the flanges  113  and  123  allows the knife blade to enter the knife channel  115  in a substantially straight orientation thereby facilitating separation of tissue. Moreover, the knife blade  190  travels in a substantially straight manner through most of the knife channel  115  and is only forced to bend around the knife channel  115  towards a distal end of the jaw members  110  and  120 . Further, the offset orientation of the knife channel, e.g., knife channel  115   b , and the disposition of the knife blade  190  traveling through the knife guide  133  also enhances the cutting effect and reduces the chances of the knife blade  190  binding during translation (extension or retraction). 
     As mentioned above, when the jaw members  110  and  120  are closed about tissue, knife channels  115   a  and  115   b  form a complete knife channel  115  to allow longitudinal extension of the knife blade  190 , from the knife path  138 , in a distal fashion to sever tissue along a tissue seal. Knife channel  115  may be completely disposed in one of the two jaw members, e.g., jaw member  120 , depending upon a particular purpose. It is also envisioned that jaw member  120  may be assembled in a similar manner as described above with respect to jaw member  110 . 
     Referring now to  FIGS.  6  and  8   , electrical lead or wire  126  is shown extending from shaft  12  through knife housing  133  and entering wire tube  125  of jaw members  120 . Wires  116  and  126  are used to supply electrical energy to electrically conductive sealing surfaces  112  and  122  of jaw members  110  and  120 , respectively. In the embodiment of  FIG.  6   , knife housing  133  also acts as a wire guide, configured to guide wires  116  and  126  to jaw members  110  and  120 . Electrical leads or wires  116  and  126  are protected by knife housing  133 . Wire tube  125  ( FIG.  8   ) of jaw member  120 , may be offset from a longitudinal axis “Y” of the forceps  10  in the same direction as the offset knife channel  115   b , such that knife channel  115   b  is disposed above the wire tube  125 . The offset “X” of the knife channel, e.g., knife channel  115   b , and the offset “Y” of the disposition of the electrical lead or wire  126  relative to longitudinal axis “A” may be different or the same depending upon a particular purpose or to facilitate manufacturing. For example, as mentioned above, the offset distance “X” may be in the range of about 0.010 inches to about 0.040 inches whereas the offset distance “Y” may be in the range about 0.040 inches to about 0.140 inches. In addition, particular “X” and “Y” configurations may be as follows: When “X” is about 0.010 inches “Y” may be about 0.040 inches; when “X” is about 0.017 inches “Y” may be about 0.070 inches; and when “X” is about 0.034 inches “Y” may be about 0.140 inches. Other configurations and offsets for “X” and “Y” are also contemplated and within the scope of this disclosure. 
     Referring now to  FIGS.  9 - 12   , one embodiment of an end effector assembly  400  for use with forceps  10  includes a pair of jaw members  402 ,  404 , a knife assembly  410 , and a cam assembly  420 . 
     One or both jaw members  402 ,  404  are moveable relative to the other about a pivot  440  operably associated with the forceps  10 . One or both jaw members  402 ,  404  are moveable between an open position ( FIGS.  9 - 11   ) and a closed position ( FIG.  12   ) for grasping tissue. One or both of the jaw members  402 ,  404  include a knife channel  406  defined therein that extends therealong. One or both of the jaw members  402 ,  404  may be adapted to connect to an electrosurgical energy source to electrosurgically treat tissue. 
     The knife assembly  410  includes a knife blade  412  and an actuation shaft  414 . The knife blade  412  may be affixed to a distal end of the actuation shaft  414 . The actuation shaft  414  is operably associated with the knife trigger assembly  70  of forceps  10  ( FIG.  1   ). The knife blade  412  is disposed distally relative to the pivot  440 . The actuation shaft  414  is configured for slidable translation through the pivot  440  to allow selective advancement of the knife blade  412  through the knife channel  406  upon activation by the knife trigger assembly  70 . 
     The cam assembly  420  is operably coupled to each moveable jaw member  402 ,  404  and is actuatable to move one or both jaw members  402 ,  404  between the open and the closed position for grasping tissue therebetween. The cam assembly  420  includes an actuator clevis  422  operably coupled to a support clevis  430  operably associated with the housing  20 . The cam assembly  420  is configured to move one or both jaw members  402 ,  404  between the open and the closed position upon selective longitudinal translation thereof. The actuator clevis  422  may be moveable via an actuator tube  450  operably associated with the shaft  12  extending from the housing  20  to actuate both jaw members  402 ,  404 . 
     The pair of jaw members  402 ,  404  are mounted to the support clevis  430  about the pivot  440 . The support clevis  430  defines an actuator bore  432  and an actuator tube bore  434  for facilitating the slidable translation of the actuator clevis  422  and the actuator tube  450  therethrough. With reference to  FIG.  9   , cable channels  470 ,  472 , etc. may also be defined through support clevis  430  for receiving one or more of the leads of the electrosurgical cable  310  ( FIG.  1   ) therethrough. 
     The pivot  440  has first and second sections  442 ,  444  defining a passage  446  therebetween configured to permit the actuation shaft  414  to slidably translate therethrough. In some embodiments, the first and second sections  442 ,  444  of the pivot  440  are fixedly connected to the support clevis  430 . The support clevis  430  is mounted to the distal end of the actuator tube  450 . The actuator tube  450  is operably associated with the drive assembly  60  for longitudinally translating the actuator tube  450 . The actuator tube  450  is configured to slidingly receive the knife assembly  410  therein. 
     The actuator clevis  422  includes one or more cam pins  424 ,  426  extending therefrom. One or both jaw members  402 ,  404  define one or more cam slots  403 ,  405  therein such that the one or more cam slots  403 ,  405  and the one or more cam pins  424 ,  426  are configured to cooperate with one another to move each moveable jaw member  402 ,  404 . The actuator tube  450  is configured to longitudinally translate the actuator clevis  422  and permit the slidable translation of the actuation shaft  414  therethrough for facilitating the translation of the knife blade  412 . The actuator tube  450  slidably translates along a knife tube  460  mounted to the pivot  440  between the first and second sections  442 ,  444 . 
     The one or more cam pins  424 ,  426  are configured to slidably engage the knife tube  460  upon the selective longitudinal translation of the actuator clevis  422 . The distal ends  424   d ,  426   d  of the cam pins  424 ,  426  are configured to slidably engage the outer surface of the knife tube  460 . As illustrated in  FIGS.  11  and  12   , the distal ends  424   d ,  426   d  of the cam pins  424 ,  426  define a pin profile that may be generally crescent-shaped for cooperating with the generally circularly-shaped outer surface of the knife tube  460 . The knife tube  460  and the pin profiles may have any suitable cross-sectional shape (e.g., circular or non-circular). The knife tube  460  defines a recess  462  adapted to mount each of the first and second sections  442 ,  444  of the pivot  440  at the distal ends  442   d ,  444   d  thereof. The distal ends  442   d ,  444   d  of each of the first and second sections  442 ,  444  define a profile configured to fixedly engage the recess  462 . The profiles of both the distal ends  442   d ,  444   d  of the first and second sections  442 ,  444  define the passage  446  between each section  442 ,  444  for engaging the recess  462  of the knife tube  460 . The passage  446  and the recess  462  may define any suitable cross-sectional shape (e.g., circular or non-circular). As illustrated in the embodiment of  FIG.  11   , the profiles of the first and second sections  442 ,  444  are each generally crescent-shaped to fixedly engage the circumferential groove that defines the recess  462  so that first and second sections  442 ,  444  provide a stationary pivot about which jaw members  402 ,  404  move. 
     In operation, upon actuation of the movable handles  30   a  and  30   b , the drive assembly  60  slidably longitudinally translates the actuator tube  450  through the actuator tube bore  434  of the support clevis  430 . The translation of the actuator tube  450  effectuates the longitudinal translation of the actuator clevis  422  through the actuator bore  432  of the support clevis  430 . As the actuator clevis  422  translates, each cam pin  424 ,  426  slides within each respective cam slot  403 ,  405  and along the outer surface of the knife tube  460 . When each cam pin  424 ,  426  translates through each respective cam slot  403 ,  405 , the jaw members  402 ,  404  translate between the first position and the second position. In effect, each respective jaw member  402 ,  404  rotates about the pivot  440  in response to the longitudinal translation of the actuator clevis  422 . Upon actuation of the knife trigger assembly  70 , the actuation shaft  414  translates through the actuator tube  450  and the knife tube  460  such that the knife blade  412  is advanced through the knife channel  406  of the jaw members  402 ,  404 . 
     With reference to  FIG.  13   , one embodiment of an end effector assembly  500  for use with forceps  10  includes a roll joint  510  secured to the distal end of the support clevis  430  and operably coupled to the actuator tube  450  for facilitating the rotational movement of the jaw members  402 ,  404 . The roll joint  510  includes a stationary portion  510   a  and rotatable portion  510   b . The stationary portion  510   a  is fixedly coupled to the handle assembly  30 . The rotatable portion  510   b  is operably coupled to the stationary portion  510   a  and the actuator tube  450 . The rotatable portion  510   b  includes one or more moveable interfaces  512  (e.g., one or more bearings, bushings, etc.) secured thereto. Each movable interface  512  is configured to permit relative rotation between the stationary portion  510   a  and the rotatable portion  510   b.    
     In operation, the actuator tube  450  is rotated which, in turn, rotates the rotatable portion  510   b  in response thereto. With the actuator tube  450  fixedly mounted to the rotatable portion  510   b  and radially movable within the stationary portion  510   a , the actuator tube  450  transmits torque to the jaw members  402 ,  404  via the roll joint  510  upon the rotational movement of the actuator tube  450 . In this manner, the jaw members  402 ,  404  may be radially rotated about the longitudinal axis “A” while the handle assembly  30  remains stationary. 
     With these embodiments, the distance to the pivot point is significantly reduced which facilitates assembly and ease of use. In certain embodiments, this shortened distance to the pivot point facilitates articulation of the end effector. 
     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 exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.