Patent Publication Number: US-10327838-B2

Title: Apparatus for performing an electrosurgical procedure

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of U.S. patent application Ser. No. 13/911,674 filed by Kerr on Jun. 6, 2013, now U.S. Pat. No. 9,492,223, which is a continuation application of U.S. patent application Ser. No. 12/792,097 filed by Kerr on Jun. 2, 2010, now U.S. Pat. No. 8,469,991, the entire contents of each of which being hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to an apparatus for performing an electrosurgical procedure. More particularly, the present disclosure relates to an electrosurgical apparatus including an end effector assembly having a pair of jaw members that provide a mechanical advantage at the end effector. 
     Description of Related Art 
     Electrosurgical instruments, e.g., electrosurgical forceps (open or closed type), are well known in the medical arts and typically include a housing, a handle assembly, a shaft and an end effector assembly attached to a distal end of the shaft. The end effector includes jaw members configured to manipulate tissue (e.g., grasp and seal tissue). Typically, the electrosurgical forceps utilizes both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize, seal, cut, desiccate, and/or fulgurate tissue. Typically, one or more driving mechanisms, e.g., a drive assembly including a drive rod, is utilized to cooperate with one or more components operatively associated with the end effector to impart movement to one or both of the jaw members. 
     In certain instances, to facilitate moving the jaw members from an open position for grasping tissue to a closed position for clamping tissue (or vice versa) such that a consistent, uniform tissue effect (e.g., tissue seal) is achieved, one or more types of suitable devices may be operably associated with the electrosurgical forceps. For example, in some instances, one or more types of springs, e.g., a compression spring, may operably couple to the handle assembly associated with the electrosurgical forceps. In this instance, the spring is typically operatively associated with the drive assembly to facilitate actuation of a movable handle associated with the handle assembly to ensure that a specific closure force between the jaw members is maintained within one or more suitable working ranges. 
     In certain instances, the shaft may bend or deform during the course of an electrosurgical procedure. For example, under certain circumstances, a clinician may intentionally bend or articulate the shaft to gain desired mechanical advantage at the surgical site. Or, under certain circumstances, the surgical environment may cause unintentional or unwanted bending or flexing of the shaft, such as, for example, in the instance where the shaft is a component of a catheter-based electrosurgical forceps. More particularly, shafts associated with catheter-based electrosurgical forceps are typically designed to function with relatively small jaw members, e.g., jaw members that are configured to pass through openings that are 3 mm or less in diameter. Accordingly, the shaft and operative components associated therewith, e.g., a drive rod, are proportioned appropriately. That is, the shaft and drive rod are relatively small. 
     As can be appreciated, when the shaft is bent or deformed (either intentionally or unintentionally) the frictional losses associated with drive rod translating through the shaft are transferred to the spring in the housing, which, in turn, may diminish, impede and/or prevent effective transfer of the desired closure force that is needed at the jaw members. Moreover, the frictional losses may also lessen the operative life of the spring, which, in turn, ultimately lessens the operative life of the electrosurgical instrument. 
     An increased mechanical advantage and/or mechanical efficiency with respect to transferring the closure force(s) from the handle assembly to the jaw members may prove advantageous in the relevant art. 
     SUMMARY 
     The present disclosure provides an endoscopic forceps. The endoscopic forceps includes a housing having a shaft that extends therefrom and defines a longitudinal axis therethrough. An end effector assembly is operatively connected to a distal end of the shaft and includes a pair of first and second jaw members. The first and second jaw members are pivotably coupled to one another. One of the first and second jaw members is movable relative to the other jaw member from an open position, wherein the first and second jaw members are disposed in spaced relation relative to one another, to a clamping position, wherein the first and second jaw members cooperate to grasp tissue therebetween. A drive mechanism includes a driving structure in operative communication with one or more cam slots operably disposed on one or both of the first and second jaw members. The driving structure includes one or more detents, wherein the distal end of the driving structure is substantially resilient and functions as a cantilever spring that is configured to flex away from the longitudinal axis when the distal tip is positioned at the proximal end of the cam slot and tissue is positioned between the first and second jaw members. 
     The present disclosure provides a forceps. The forceps includes a housing having a shaft that extends therefrom and defines a longitudinal axis therethrough. An end effector assembly is operatively connected to a distal end of the shaft and includes a pair of first and second jaw members. The first and second jaw members are pivotably coupled to one another. One of the first and second jaw members is movable relative to the other jaw member from a clamping position, wherein the first and second jaw members cooperate to grasp tissue therebetween, to an open position, wherein the first and second jaw members are disposed in spaced relation relative to one another. A drive mechanism includes a drive wire having a substantially resilient distal end including a distal tip with a camming member in operative communication with one or more cam slots operably disposed on the movable jaw member. The drive wire includes at least one detent. One or more stop members are operably disposed adjacent a distal end of the shaft and are configured such that contact between the stop member and detent corresponds to the distal tip being positioned at a proximal end of the cam slot causing the at least one movable jaw member to move from the clamping position to the open position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Various embodiments of the present disclosure are described hereinbelow with references to the drawings, wherein: 
         FIG. 1A  is a side, perspective view of an endoscopic bipolar forceps showing an end effector assembly including jaw members according to an embodiment of the present disclosure; 
         FIG. 1B  is a side, perspective view of the endoscopic bipolar forceps depicted in  FIG. 1A  illustrating internal components associated with a handle assembly associated with the endoscopic bipolar forceps; 
         FIGS. 2A-2C  are schematic views of the jaw members depicted in  FIGS. 1A and 1B  illustrating a distal end of a driving structure according to an embodiment of the present disclosure; and 
         FIGS. 3A and 3B  are schematic views of the jaw members depicted in  FIGS. 1A and 1B  illustrating a distal end of a driving structure according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Detailed embodiments of the present disclosure are disclosed herein; however, the disclosed embodiments are merely examples 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. 
     In the drawings and in the descriptions that follow, the term “proximal,” as is traditional, will refer to an end which is closer to the user, while the term “distal” will refer to an end that is farther from the user. 
     With reference to  FIGS. 1A and 1B , an illustrative embodiment of an electrosurgical apparatus, e.g., a bipolar forceps  10  (forceps  10 ) is shown. Forceps  10  is operatively and selectively coupled to an electrosurgical generator (not shown) for performing an electrosurgical procedure. As noted above, an electrosurgical procedure may include sealing, cutting, cauterizing coagulating, desiccating, and fulgurating tissue all of which may employ RF energy. The electrosurgical generator may be configured for monopolar and/or bipolar modes of operation and may include or be in operative communication with a system that may include one or more processors in operative communication with one or more control modules (not shown) that are executable on the processor. The control module may be configured to instruct one or more modules to transmit electrosurgical energy, which may be in the form of a wave or signal/pulse, via one or more cables (e.g., an electrosurgical cable  310 ) to the forceps  10 . 
     Forceps  10  is shown configured for use with various electrosurgical procedures and generally includes a housing  20 , electrosurgical cable  310  that connects the forceps  10  to the electrosurgical generator, a rotating assembly  80  and a trigger assembly  70 . For a more detailed description of the rotating assembly  80 , trigger assembly  70 , and electrosurgical cable  310  (including line-feed configurations and/or connections), reference is made to commonly-owned U.S. patent application Ser. No. 11/595,194 filed on Nov. 9, 2006, now U.S. Patent Publication No. 2007/0173814. 
     With continued reference to  FIGS. 1A and 1B , forceps  10  includes a shaft  12  that has a distal end  14  configured to mechanically engage an end effector assembly  100  operably associated with the forceps  10  and a proximal end  16  that mechanically engages the housing  20 . 
     One or more positioning structures are operably associated with the shaft  12 . More particularly, one or more stop members  19  of suitable proportion are operably disposed adjacent the distal end  14  of the shaft  12  ( FIG. 2A ). Stop member  19  includes a generally circumferential configuration and is operably coupled to an internal frame of the shaft  12  by one or more suitable coupling methods. In the illustrated embodiment, stop member  19  is monolithically formed with the shaft  12 . Stop member  19  is in operative communication with a drive mechanism  130  ( FIG. 1B ). Specifically, stop member  19  includes an aperture  21  that is dimensioned to receive a driving structure  133  that is operably associated with the drive mechanism  130 . More specifically, aperture  21  includes a diameter that accommodates proximal and distal translation of the driving structure  133  therethrough. Stop member  19  is configured to limit and/or prevent proximal translation of the driving structure  133 , or operative component associated therewith, described in greater detail below. 
     Handle assembly  30  includes a fixed handle  50  and movable handle  40  ( FIGS. 1A and 1B ). In one particular embodiment, fixed handle  50  is integrally associated with housing  20 . Movable handle  40  is movable relative to fixed handle  50  for effecting movement of one or more components, e.g., driving structure  133 , operably associated with drive mechanism  130  ( FIG. 1B ). 
     Drive mechanism  130  is in operative communication with movable handle  40  (see  FIGS. 1A and 1B ) for imparting movement of one or, in some instances, both of a pair of jaw members  110 ,  120  of end effector assembly  100 . More particularly, one or more suitable mechanical interfaces, e.g., a linkage interface, gear interface, or combination thereof operably couples the movable handle  40  to the drive mechanism  130 . In the embodiment illustrated in  FIGS. 1A and 1B , proximal movement of the movable handle  40  moves the moveable jaw member, e.g., jaw member  120 , from the normally open position to the clamping position. 
     Conventional drive mechanisms and/or assemblies typically utilize one or more types of springs, e.g., a compression spring, to facilitate closing the jaw members  110  and  120 . For illustrative purposes, a compression spring  131  (see  FIG. 1B ) is shown separated from the housing  20 . In accordance with the present disclosure, the combination of the drive mechanism  130  including driving structure  133  that operably couples to a cam slot  140  ( FIGS. 2A-2C ) operably associated with one or both of the jaw members  110  and  120  functions to facilitate moving the jaw members  110  and  120  and, thus, may eliminate the need for the compression spring  131 . 
     Driving structure  133  is configured such that proximal movement thereof causes jaw member  120  to move from the open position ( FIGS. 1A and 2A ) to the closed or clamping position ( FIGS. 1B and 2B ) and vice versa. To this end, driving structure  133  may be any suitable driving mechanism including but not limited to a wire, rod, cable, band, etc. In the illustrated embodiment, driving structure  133  is a drive wire of suitable proportion that is dimensioned to translate within the aperture  21  of the stop member  19  (see  FIG. 2A , for example). Drive wire  133  is dimensioned such that the drive wire  133  does not to “buckle” or “kink” when the drive wire  133  is moved proximally and/or distally within the shaft  12  and through the aperture  21 . 
     Drive wire  133  includes a proximal end (not explicitly shown) that is in operative communication with the movable handle  40 . 
     A blocking member in the form of a detent  137  having dimensions of suitable proportion is operably associated with the drive wire  133  ( FIGS. 2A-2C ). In the illustrated embodiment, detent  137  includes a generally cylindrical configuration and is operably coupled to the drive wire  133  by one or more suitable coupling methods. For illustrative purposes, detent  137  is shown monolithically formed with the drive wire  133 . Detent  137  is disposed adjacent a distal end  135  of the drive wire  133  and distally relative to the stop member  19  ( FIGS. 2A-2C ). 
     Detent  137  is configured to contact stop member  19  when the movable handle  40  is moved proximally and the drive wire  133  is moved proximally through the stop member  19 . Contact between the stop member  19  and detent  137  limits and/or prevents movement or translation of the drive wire  133  through the stop member  19  thereby limiting movement of distal end  135  within the cam slot  140  such that a portion, e.g., a distal tip  139 , of the distal end  135  is positioned at a predetermined location, e.g., a proximal end  144 , of the cam slot  140 . That is, drive wire  133  and, thus, distal end  135  are configured to move a distance “D” that is approximately equal to the distance that the distal tip  139  moves within the cam slot  140  when the movable handle  40  is moved proximally, see  FIG. 2A . Moving and/or positioning the distal tip  139  the predetermined distance “D” within the cam slot  140  provides a required closure force between the jaw members  110  and  120  when tissue is positioned between the jaw members  110  and  120 , described in greater detail below. 
     Distal end  135  includes a substantially linear or straight configuration that is in general alignment with the cam slot  140  when the first and second jaw members  110  and  120  are in a “neutral” condition. As used herein, the “neutral” condition refers to the condition where the distal tip  139  is positioned at the proximal end  144  and without tissue positioned the jaw members  110  and  120  ( FIG. 2B ). Distal end  135  functions as a cantilever spring or “spring-board” that is configured to “flex” away from the longitudinal axis “A-A” when the distal tip  139  is positioned at the proximal end  144  of the cam slot  140  and tissue is positioned between the jaw members  110  and  120  ( FIG. 2C ). When the distal end  135  is in the “flexed” position illustrated in  FIG. 2C , the distal end  135  exerts an upward force “F 2 ” that is directed toward the longitudinal axis “A-A.” Likewise, when the distal tip  139  is positioned at the distal end  146  of the cam slot  140 , the distal end  135  is configured to “flex” away from the longitudinal axis “A-A.” However, when the distal end  135  is in the “flexed” position illustrated in  FIG. 2A , the distal end  135  exerts a downward force “F 1 ” that is directed toward the longitudinal axis “A-A.” The downward force “F 1 ” maintains the jaw member  120  in a spaced-apart relation with respect to the jaw member  110 . That is, the downward force “F 1 ” pivots the jaw member  120  away from the jaw member  110  and into the open position. This downward force “F 1 ” is a result of the configuration of the cam slot  140  and the size and/or length of the distal end  135 . 
     Distal end  135 , or portion thereof, e.g., distal tip  139 , is configured to translate or move within one or, in some instances, both of the jaw members  110  and  120 . For illustrative purposes, the end effector  100  is shown having a unilateral jaw design, i.e., jaw member  120  is configured to pivot and/or rotate with respect to jaw member  110 . Accordingly, distal end  135  is configured to translate or move within jaw member  120 . More particularly, the distal tip  139  of the distal end  135  is in operative communication with the cam slot  140  and is configured to translate or move within the cam slot  140  and move the jaw member  120  from the open to the closed or clamping positions and vice versa. In the clamping position, and with tissue positioned between the jaw members  110  and  120 , the distal end  135  generates a closure force ranging from about 3 kg/cm 2  to about 16 kg/cm 2  between the jaw members  110  and  120 . 
     In certain embodiments, a camming member  142  (shown in phantom) may be operably coupled to the distal tip  139 , via one or more suitable coupling methods, e.g., via a spot weld. Camming member  142  is configured to facilitate moving (and in certain instances camming the jaw member  120 ) the distal tip  139  and/or distal end  135  within the cam slot, i.e., past a transition point “Tp” of the cam slot  140 , see  FIG. 2A . The transition point “Tp” corresponds to location in the cam slot  140  that is in substantial alignment with a pivot pin  111 , see  FIG. 2A , for example. 
     End effector assembly  100  is illustrated operably disposed at the distal end  14  of the shaft  12  ( FIGS. 1A and 1B ). End effector assembly  100  includes opposing jaw members  110  and  120  that mutually cooperate to grasp, seal and, in some cases, divide large tubular vessels and large vascular tissues. As noted above, in the illustrated embodiment, jaw member  110  is stationary and the jaw member  120  is movable relative to the jaw member  110 . Jaw members  110 ,  120  are operatively and pivotably coupled to each other and located adjacent the distal end  14  of shaft  12 . Respective electrically conductive seal plates  118  and  128  are operably supported on and secured to respective jaw housings  117  and  127  of respective the jaw members  110  and  120 . Jaw members  110  and  120  including respective jaw housings  117  and  127 , and operative components associated therewith, may be formed from any suitable material, including but not limited to metal, metal alloys, plastic, plastic composites, and so forth. 
     Jaw housing  127  and  117  of the respective jaw members  110  and  120  are substantially identical to each other. In view thereof, the operative features of jaw housing  127  are described in detail, and only those features that are unique to jaw member  110  are described hereinafter. 
     With reference to  FIGS. 2A-2C , an embodiment of jaw housing  127  is illustrated. Jaw housing  127  includes a distal end  127   a  that is configured to operably support seal plate  128  and a proximal end  127   b  that operably couples to the distal end  14  of shaft  12 . Proximal end  127   b  includes a generally rectangular configuration,  FIG. 2A , and is dimensioned to move, e.g., pivot, within the shaft  12  from the closed or clamping position to the open position. Proximal end  127   b  is dimensioned to include one or more cam slots  140 . A pivot pin  111  couples the first and second jaw members  110  and  120 , respectively ( FIG. 2A ) for pivotal movement relative to one another. 
     Cam slot  140  includes a generally straight, elongated configuration having proximal end  144  that is substantially aligned with the longitudinal axis “A-A.” Proximal end  144  of the cam slot  140  is configured such that with tissue positioned between the jaw members  110  and  120 , and when the detent  137  contacts the stop member  19 , the distal tip  139  of the distal end  135  is positioned about the proximal and  144 . With the distal tip  139  positioned about the proximal end  144 , distal end  135  pivots away, e.g., downward, from the longitudinal axis “A-A” and exerts an upward force “F 2 ” such that the jaw member  120  clamps down on tissue with a closure force ranging from about 3 kg/cm 2  to about 16 kg/cm 2 . 
     Cam slot  140  extends substantially along a length of the proximal end  127   b  and includes a distal end  146  that is elevated or “offset” with respect to the proximal end  144 . More particularly, distal end  146  is disposed at a predetermined position above the pivot pin  111  ( FIG. 2A ). Positioning the distal end  146  above the pivot pin  111  facilitates maintaining the jaw member  120  in the open configuration. That is, with the distal tip  139  positioned about the distal end  146 , the distal end  135  pivots away, e.g., upward, from the longitudinal axis “A-A” and exerts a downward force “F 1 ” such that the jaw member  120  moves away from the jaw member  110 . 
     Unlike jaw housing  127  of jaw member  120 , jaw housing  117  of jaw member  110  does not include a cam slot  140 , i.e., due to the unilateral jaw configuration, and does not move with respect to the jaw member  120 . 
     The jaw members  110  and  120  may be coupled to each other via any suitable coupling methods. In the illustrated embodiment, an opening  108  is defined in and extends through the each of the jaw housing  117  and  127  and is configured to receive pivot pin  111 . Opening  108  is shown engaged with pivot pin  111  and as such is not explicitly visible. 
     In an assembled configuration, pivot pin  111  is positioned within the openings associated with each of the jaw members  110  and  120 . Once assembled, the jaw members  120  and/or jaw member  110  may be pivotably supported at the distal end  14  of the shaft  12  by known methods, such as, for example, by the method described in commonly-owned U.S. Pat. No. 7,597,693 to Garrison filed on Jun. 13, 2003. 
     In use, initially distal tip  139  of the distal end  135  is positioned at distal end  146  of the cam slot  140  and the jaw members  110  and  120  are in an open configuration (see  FIG. 1A  in combination with  FIG. 2A ). Subsequently, tissue is positioned between the jaw members  110  and  120 . Movable handle  40  is moved proximally ( FIG. 1B ), which, in turn, causes the drive wire  133  including detent  137  to move proximally in the direction indicated by directional arrow “G” ( FIG. 2A ). When detent  137  and distal end  135  including distal tip  139  have moved the predetermined distance “D,” the detent  137  contacts the stop member  19  and the distal tip  139  is positioned at the proximal end  144  of the cam slot  140 . In this position, the distal end  135  and/or distal tip  139  provides the upward force “F 2 ” such that the jaw member  120  clamps down on tissue positioned between the jaw members  110  and  120  (see  FIG. 1B  in combination with  FIG. 2C ) with a closure force that ranges from about 3 kg/cm 2  to about 16 kg/cm 2 . Subsequently, electrosurgical energy is transmitted to the seal plates  118  and  128  such that an electrosurgical effect, e.g., tissue seal, is achieved at tissue. Thereafter, movable handle  40  is released, which, in turn, causes distal tip  139  of the drive wire  133  to return to the distal end  146  of the cam slot  140  and the jaw member  120  to move back to open position. The drive mechanism  130  including a distal end  135  configured as a cantilever spring and the cam slot  140  associated with the jaw member  120  provides an additional mechanical advantage at the jaws  110  and  120  and helps reduce the frictional losses that are typically associated with conventional forceps when a drive rod is translated within a shaft to make the necessary closure force to seal tissue, i.e., the closure force is offloaded and/or diminished by the distal end  135  of the drive wire  133  and cam slot configuration  140 . 
     From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, in certain instances it may prove useful to have both of the jaw members  110  and  120  move relative to each other. In this instance, a cam slot  140  may be operably disposed on each of the jaw members  110  and  120 . Accordingly, a drive mechanism  130  may include a pair of drive wires  133  that operably couple to a respective jaw member. 
     It is contemplated that in certain instances one or more resilient members, e.g., compression spring (not shown), may be operably associated with or coupled to either the stop member  19  or detent  137 . In this instance, the spring may be configured to provide a “pushing” force against the proximal surface of the detent  137 . This “pushing” force is configured to facilitate “bending” or “flexing” of the distal end  135 . 
     It is contemplated that in certain embodiments, the stop  19  and detent  137  may function as or include a ratchet and pawl system. In this instance, the stop  19  and detent  137  may be configured to lock the jaw members  110  and  120  in one or more positions, e.g., the clamping position. 
     It is contemplated that in some embodiments, a distal end that is configured to rotate within a cam slot that is operably disposed on the jaw member  120  may be utilized with the drive mechanism  130  to impart movement of the jaw member  120 . 
     More particularly, and with reference to  FIGS. 3A and 3B , a rotatable distal end  235  is illustrated. Distal end  235  is configured to rotate within a cam slot  240  when the drive wire  133  is moved, e.g., proximally or distally, see  FIGS. 3A and 3B . More particularly, the distal end  235  is rotatable within the cam slot  240  during translation therein when the movable handle  40  is moved proximally and/or distally. To this end, the distal end  235  is rotatably coupled to the drive wire  133  by one or more suitable coupling methods. In the embodiment illustrated in  FIGS. 3A and 3B , the distal end  235  is coupled to a detent  237  of the drive wire  133  via a threaded screw connection, not explicitly shown. For example, the distal end  235  may include a threaded male end that is configured to screw into a threaded female end on the detent  237 . In this instance, when the drive wire  133  is moved, e.g., either proximally or distally, the distal end  235  will rotate within the cam slot  240  and with respect to the detent  237 , i.e. the distal end  235  screws into or out of the detent  237 . 
     Distal end  235  includes a generally arcuate portion  241  that facilitates maintaining the jaw member  120  in the open or clamped configuration. More particularly, the arcuate portion  241  provides an upward force “H 1 ” that is directed away from the longitudinal axis “A-A,” when the distal tip  239  is positioned about a distal end  246  of the cam slot  240  ( FIG. 3A ). Likewise, the arcuate portion  241  provides a downward force “H 2 ” that is directed away from the longitudinal axis “A-A,” when the distal tip  239  is positioned about a proximal end  244  of the cam slot  240  ( FIG. 3B ). The distal end  235  rotates from an initial position that corresponds to the jaw member  120  in the clamping position, see  FIG. 3A , to a subsequent or final position, that corresponds to the jaw member  120  in the open position, see  FIG. 3B . 
     A significant difference of a drive mechanism  130  that utilizes the distal end  235  when compared with a drive mechanism  130  that utilizes the distal end  135  is that, because the distal end  235  of the drive wire  233  rotates within the cam slot  240 , machining tolerances that may be associated with the manufacture of the cam slot  240  are minimized. More particularly, unlike the distal end  146 , the distal end  246  of the cam slot  240  may be positioned above, below or aligned with the pivot pin  111 . That is, the upward force “H 1 ” generated by the arcuate portion  241  of the distal end  235  facilitates maintaining the movable jaw member  120  in the clamping configuration when the distal tip  239  is positioned at the distal end  246  of the cam slot  240 . For illustrative purposes, the distal end  246  is shown disposed substantially aligned with the pivot pin  111 . 
     Cam slot  240  includes one or more tracks, bores, grooves, protuberances, detents, etc. that are configured to guide, direct, turn, maneuver, or otherwise rotate the distal tip  239  when the distal end  235  is moved within and along a length of the cam slot  240 . For example, and in one particular embodiment, a generally helical groove or bore  248  is disposed within the cam slot  240  and extends along a length thereof. The helical bore  248  may be dimensioned to receive a detent or protuberance, e.g., a camming member  242  that is configured to move therein when the distal end  235  is moved. More particularly, when the distal end  235  including the distal tip  239  moves within the cam slot  240 , the camming member  242  moves within the helical bore  248 . A path or course as defined by the helical bore  248  is of such configuration that when the camming member  242  travels along a predetermined length thereof, the distal end  235  is caused to rotate from the initial position to the final position. Other methods of rotating the distal end  235  within the cam slot  240  are contemplated and appreciated. 
     In use, initially distal tip  239  of the distal end  235  is positioned at distal end  246  of the cam slot  240  and the jaw members  110  and  120  are in a closed configuration ( FIG. 3A ). Movable handle  40  is moved proximally, which, in turn, causes the drive wire  133  including detent  237  to move proximally in the direction indicated by directional arrow “G” ( FIG. 3B ). As the distal end  235  moves proximally, the distal tip  239  moves within and follows the path, e.g., the generally helical path, of the helical bore  248  disposed within the cam slot  240 , which, in turn, causes the distal end  235  including the arcuate portion  241  to rotate, e.g., in a counter-clockwise direction, and “unscrew” from the detent  237 . When the detent  237  and distal end  235  including distal tip  239  have moved a predetermined distance “D,” detent  237  contacts the stop member  19  and the distal tip  239  is positioned at the proximal end  244  of the cam slot  240 . In this position, the arcuate portion  241  of the distal end  235  and/or distal tip  239  provides a downward force “H 2 ” such that the jaw member  120  moves away from jaw member  110  and toward the open position ( FIG. 3B ). Tissue is positioned between the jaw members  110  and  120 . Thereafter, movable handle  40  is released, which, in turn, causes distal tip  239  of the drive wire  133  to return to the distal end  246  of the cam slot  240  and the jaw member  120  to move back to the closed or clamped position such that tissue is grasped therebetween. Subsequently, electrosurgical energy is transmitted to the seal plates  118  and  128  such that an electrosurgical effect, e.g., tissue seal, is achieved at tissue. The drive mechanism  130  including a rotatable distal end  235  that is configured to translate and rotate within the cam slot  240  associated with the jaw member  120  provides the same mechanical advantage as described above. 
     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.