Patent Publication Number: US-10772642-B2

Title: Surgical forceps

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit of and priority to U.S. Provisional Application Ser. No. 62/376,434, filed on Aug. 18, 2016 the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to surgical forceps and, more particularly, to an endoscopic surgical forceps configured for treating and/or cutting tissue. 
     Background of Related Art 
     A surgical forceps is a pliers-like device which relies on mechanical action between its jaw members to grasp, clamp, and constrict tissue. Typically, at least one handle or lever is used to open and close the jaw members, and to provide compression force on tissue between the jaw members, to lock the jaw members in a closed position, and/or to apply energy to the jaw members to seal the tissue disposed therebetween. 
     Generally, such handles and levers used on surgical instruments are one of two types. One type is a simple pivoted handle that provides a near constant mechanical advantage throughout its stroke, and which is useful in many surgical situations. The second type of handle includes an additional link to provide a geometrically increasing mechanical advantage toward the end of its stroke to help provide the force necessary to compress tissue. 
     Both of these types of handles fix the mechanical advantage of the drive system such that the drive system cannot be optimized independently over the entire lever stroke. Often times, it may be desirable for a system to include fine dissection capability (a relatively large amount of handle travel for a relatively small amount of jaw member movement) when the jaw members are in an initial, or open position, and to include a high mechanical advantage while applying compression force to tissue disposed between the jaw members when the jaw members are in or near their approximated position (to help reduce surgeon fatigue, for instance). However, current handles are generally unable to achieve both of these desires in a single system. 
     SUMMARY 
     The present disclosure relates to a surgical instrument including a housing, an elongated shaft extending distally from the housing and defining a longitudinal axis, an end effector assembly, and a trigger assembly. The end effector assembly is disposed adjacent a distal end of the elongated shaft, and includes a first jaw member and a second jaw member. One or both of the jaw members is movable with respect to the other jaw member from a spaced-apart position to a position closer to the other jaw member for grasping tissue. The trigger assembly is disposed in mechanical cooperation with the housing and is configured to longitudinally translate a drive member. The trigger assembly includes a trigger, a gear assembly, a spool, a slider, and a flexible drive member. The trigger is disposed in mechanical cooperation with the gear assembly. The flexible drive member is configured to engage the gear assembly, the spool, and the slider. Movement of the trigger with respect to the housing results in movement of the flexible drive member with respect to the housing and longitudinal movement of the slider with respect to the housing. 
     In aspects of the present disclosure, the surgical instrument further includes a drive assembly disposed at least partially within the housing. The drive assembly includes a drive bar extending at least partially through the elongated shaft such that longitudinal translation of the drive bar causes the jaw members to move between the spaced-apart position and the closer position for grasping tissue. 
     In other aspects, the drive bar is rotatable about the longitudinal axis with respect to the housing. In yet other aspects, the drive bar is rotatable about the longitudinal axis with respect to the slider. 
     In still other aspects, the trigger assembly further includes a ring. The ring is rotationally supported by the slider. In aspects of the present disclosure, the ring is rotationally fixed with respect to the drive bar. In other aspects, the ring is longitudinally translatable with respect to the drive bar. 
     In yet other aspects, the drive member is longitudinally translatable with respect to the drive bar. In still other aspects, the drive bar is rotatable with respect to the drive member. 
     In aspects of the present disclosure, the gear assembly includes a first gear and a second gear. The first gear is configured to engage the trigger, and the second gear is configured to engage the spool. 
     The present disclosure also relates to a trigger assembly for use with a surgical instrument. The trigger assembly includes a trigger, a gear assembly disposed in mechanical cooperation with the trigger, a spool, a slider, and a flexible drive member. The flexible drive member is configured to engage the gear assembly, the spool, and the slider. Actuation of the trigger results in movement of the flexible drive member with respect to the spool and longitudinal movement of the slider with respect to the spool. 
     In aspects of the present disclosure, the trigger assembly includes a ring rotationally supported by the slider. In other aspects, the ring is longitudinally translatable with respect to the spool. 
     In still other aspects, the gear assembly includes a first gear and a second gear. The first gear is configured to engage the trigger, and the second gear is configured to engage the spool. In yet other aspects, the first gear and the second gear are rotationally fixed with respect to each other. 
     In aspects of the present disclosure, the flexible drive member is in contact with the spool and the slider. 
     In other aspects, the spool includes a spool gear having a plurality of teeth configured to engage a portion of the gear assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of the present disclosure are described herein with reference to the drawings wherein like reference numerals identify similar or identical elements: 
         FIG. 1  is a perspective view of a surgical forceps provided in accordance with the present disclosure; 
         FIG. 2  is a sectional view of a handle assembly of the surgical forceps of  FIG. 1  where a first cam of a first handle is shown, and where a second cam of a second handle is omitted; 
         FIGS. 3-6  are perspective views of internal components of the handle assembly of  FIGS. 1 and 2 ; 
         FIG. 6A  is a perspective view of internal components of a handle assembly according to an embodiment of the present disclosure; 
         FIG. 7  is a sectional view of internal components of the handle assembly of  FIGS. 1-6 ; 
         FIG. 8  is a sectional view of another embodiment of a surgical forceps provided in accordance with the present disclosure; 
         FIGS. 9-12  are perspective views of internal components of a handle assembly of the surgical forceps of  FIG. 8 ; 
         FIG. 13  is a sectional view of a handle assembly of another embodiment of a surgical forceps provided in accordance with the present disclosure; 
         FIG. 14  is a sectional view of a trigger assembly of the surgical forceps of  FIG. 13 ; 
         FIGS. 15 and 16  are perspective views of the trigger assembly of the surgical forceps of  FIGS. 13-14 ; and 
         FIG. 17  is a schematic illustration of a surgical system in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the presently disclosed surgical forceps are described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein the term “distal” refers to that portion of the surgical forceps that is farther from the user, while the term “proximal” refers to that portion of the surgical forceps that is closer to the user. 
     With initial reference to  FIG. 1 , an embodiment of a surgical forceps in accordance with the present disclosure is shown generally identified by reference character  10 . Although surgical forceps  10  is shown configured for use in connection with endoscopic surgical procedures, the present disclosure is equally applicable for surgical instruments used in open surgical procedures and in connection with any suitable surgical instrument. For the purposes herein, forceps  10  is generally described. 
     Forceps  10  is adapted for use in various surgical procedures and generally includes a housing  20 , a handle assembly  30 , a trigger assembly  70 , a rotating assembly  80 , and an end effector assembly  100 . Jaw members  110  and  120  of end effector assembly  100  mutually cooperate to grasp, treat, seal and/or cut tissue. Forceps  10  further includes a shaft  12  having a distal end  16  that mechanically engages end effector assembly  100 , and a proximal end  14  that mechanically engages housing  20 . Forceps  10  may be configured to connect to a source of energy, e.g., a generator (not shown), forceps  10  may be configured as a battery powered instrument, or forceps  10  may be manually powered (e.g., when providing electrosurgical energy is not desired). 
     As shown in  FIGS. 1 and 2 , for example, handle assembly  30  includes a first movable handle  30   a  and a second movable  30   b  disposed on opposite sides of housing  20 . Handles  30   a  and  30   b  are movable relative to one another to actuate end effector assembly  100 , as will be described in greater detail below. Further, while two movable handles  30   a  and  30   b  are shown and described herein, the present disclosure also includes handle assembly  30  including a single movable handle, as shown in  FIGS. 3-16 , for example. Here, in addition to the single movable handle, a finger loop  34  is included on the opposite side of housing  20  as the single movable handle. Additionally, handle  30   b  may include the same, mirror-image, or corresponding features as handle  30   a.    
     Rotating assembly  80  is mechanically coupled to housing  20  and is rotatable in either direction, to rotate shaft  12  and, thus, end effector assembly  100  about a longitudinal axis “X” defined by shaft  12 . Such a configuration allows end effector assembly  100  to be rotated in either direction with respect to housing  20 . 
     Handle(s)  30   a  and/or  30   b  of handle assembly  30  ultimately connect to a drive assembly  60  disposed within housing  20  and that extends through shaft  12  which, together, cooperate to impart movement of jaw members  110  and  120  from an open position wherein jaw members  110  and  120  are disposed in spaced relation relative to one another, to a closed or approximated position wherein jaw members  110  and  120  cooperate to grasp tissue therebetween. 
     Handles  30   a  and  30   b  of handle assembly  30  each include a finger loop or an aperture  33   a  and  33   b , respectively, defined therein which enables a user to grasp and move handles  30   a  and  30   b  relative to one another and relative to housing  20  between a spaced-apart position and an approximated position. In the embodiment where handle assembly  30  includes two handles  30   a  and  30   b , each handle  30   a  and  30   b  is pivotably coupled to housing  20  at its respective distal end  31   a ,  31   b  via pivot pins  34   a ,  34   b , respectively, and extends proximally to proximal ends  32   a ,  32   b , respectively, thereof. As mentioned above, handles  30   a ,  30   b  are coupled to drive assembly  60  such that pivoting of handles  30   a ,  30   b  about pivot pins  34   a ,  34   b , respectively, and relative to one another effects pivoting of jaw members  110 ,  120  between the open and closed positions, as discussed in further detail below. In the embodiment where handle assembly  30  includes a single movable handle  30   a  and a finger loop  34 , handle  30   a  is pivotably coupled to housing at its distal end  31   a  via pivot pin  34   b . Here, movement of handle  30   a  with respect to housing  20  effects pivoting of jaw members  110 ,  120  between the open and closed positions. 
     With particular reference to  FIG. 2 , drive assembly  60  includes a drive bar  62  defining a proximal end  62   a  disposed within housing  20  and a distal end  62   b  that extends through shaft  12 , ultimately coupling to jaw members  110 ,  120 . A mandrel  64  disposed within housing  20  is engaged with the proximal end  62   a  of drive bar  62 . Mandrel  64  is slidably engaged with at least one track  22  (see  FIG. 2 ) defined within housing  20  to guide longitudinal translation of mandrel  64  and, thus, drive bar  62 , relative to housing  20 . Other suitable guide/alignment mechanisms are also contemplated. A spring  69  is positioned within mandrel  64  and is configured to prevent over compression of tissue when jaw members  110 ,  120  are in the closed or approximated position. 
     A follower  75  is rotatably supported by an axle  76 , which extends through a bore of follower  75 . Axle  76  is supported (e.g., rotatably supported) by proximal extensions  64   a ,  64   b  of mandrel  64 . A cam follower (e.g., a pin within a sleeve)  65  is also supported (e.g., rotatably supported) by proximal extensions  64   a ,  64   b  of mandrel  64 . 
     While the following description discusses the use of two handles  30   a ,  30   b , the use of a single handle  30   a  may also be utilized without departing from the scope of the present disclosure. In order to move jaw members  110 ,  120  from the open position to the closed position, handles  30   a  and/or  30   b  are squeezed, e.g., pivoted about pivot pins  34   a ,  34   b , inwardly towards one another and housing  20 . As handle(s)  30   a ,  30   b  are pivoted in this manner, proximal ends  32   a ,  32   b  of handles  30   a ,  30   b  are approximated relative to housing  20  and one another. The approximation of proximal ends  32   a ,  32   b  of handles  30   a ,  30   b  towards one another causes extensions  140   a ,  140   b  of respective handles  30   a ,  30   b  to urge follower  75 , mandrel  64  and drive bar  62  proximally, thus approximating jaw members  110 ,  120 . Movement of handles  30   a ,  30   b  toward their open position causes extensions  140   a ,  140   b  to urge cam follower  65 , mandrel  64  and drive bar  62  distally, thus causing jaw members  110 ,  120  to move toward their open position, as further described below. The spring force of spring  69  may be configured such that jaw members  110 ,  120  impart a closure force between jaws within a range of about 3 kg/cm 2  to about 16 kg/cm 2 , although other closure forces are also contemplated. 
     Additionally, with reference to  FIGS. 3-6 , extension  140   a  includes a rib  150  thereon. The shape of rib  150  is arcuate when used with a pivoting handle  30   a ; rib  150  may be linear when used with a non-pivoting handle (not shown). Rib  150  is configured to be contacted by a roller  160 . 
     As shown in  FIGS. 4-6 , roller  160  is supported by a support  170 . Support  170  is fixed to housing  20  of surgical forceps  10  and includes a pin  172  extending through a leg  174  of support  170 . Pin  172  rotationally supports roller  160 . Roller  160  is longitudinally fixed with respect to housing  20  and is configured to engage rib  150  of extension  140   a.    
     As handle  30   a , and thus extension  140   a , is moved, roller  160  moves along rib  150 . More particularly, as handle  30   a  is moved, roller  160  contacts and thus supports a distal wall  152  of rib  150 . For example, when handle  30   a  is moved generally downward (as viewed in  FIG. 3 ) to approximate the jaw members, for instance, roller  160  contacts distal wall  152  of rib  150 . Thus, roller  160  provides support to rib  150 , and thus handle  30   a , during approximation of jaw members, e.g., to restrict or minimize unintended bending or flexing motion in extension  140   a , handle  30   a , and other features within housing  20 . 
     An alternate embodiment is shown in  FIG. 6A , which includes a first roller  160   a  and a second roller  160   b . Each of first roller  160   a  and second roller  160   b  is supported by support  170 . Support  170  is fixed to housing  20  of surgical forceps  10  and includes a first pin  172   a  and a second pin  172   b  extending through leg  174  of support  170 . First pin  172   a  rotationally supports first roller  160   a , and second pin  172   b  rotationally supports second roller  160   b . First and second rollers  160   a ,  160   b  are longitudinally fixed with respect to housing  20  and are configured to engage rib  150  of extension  140   a.    
     As handle  30   a , and thus extension  140   a , is moved, first and second rollers  160   a ,  160   b  move along rib  150 . More particularly, as handle  30   a  is moved, first roller  160   a  contacts and thus supports distal wall  152  of rib  150 . For example, when handle  30   a  is moved generally downward (as viewed in  FIG. 3 ) to approximate the jaw members, for instance, first roller  160   a  contacts distal wall  152  of rib  150 . Thus, first roller  160   a  provides support to rib  150 , and thus handle  30   a , during approximation of jaw members, e.g., to restrict or minimize unintended bending or flexing motion in extension  140   a , handle  30   a , and other features within housing  20 . Additionally, when handle  30   a  is moved generally upward (as viewed in  FIG. 3 ) to open the jaw members, for instance, second roller  160   b  contacts a proximal wall  152   b  of rib  150 . Thus, second roller  160   b  provides support to rib  150 , and thus handle  30   a , during opening of jaw members, e.g., to restrict or minimize unintended bending or flexing motion in extension  140   a , handle  30   a , and other features within housing  20 . 
     During use, a surgeon may desire fine (vs. gross) control of jaw members  110 ,  120  during some stages of use. For example, the surgeon may wish to have greater control of the movement of the jaw members  110 ,  120  during dissection of tissue, manipulation of tissue, and precise placement of jaw members  110 ,  120  about target tissue. For such fine control of jaw members  110 ,  120 , a relative large amount of travel of handles  30   a ,  30   b  (or a single handle) would correspond to a relative small amount of travel of jaw members  110 ,  120 . Some surgeons may also desire to have a high mechanical advantage during other stages of use. For example, a surgeon may wish to utilize a high mechanical advantage while applying compression force to tissue. To achieve such a high mechanical advantage, a relative small amount of travel of handles  30   a ,  30   b  would correspond to a relative large amount of travel of jaw members  110 ,  120 . Typically, surgical instruments only allow for either fine control of jaw members  110 ,  120  or a high mechanical advantage. Examples of one surgical forceps configured to allow both fine control of jaw members and a high mechanical advantage at different stages of the actuation stroke of handles is described in U.S. Provisional Patent Application Ser. No. 62/247,279, filed on Oct. 28, 2015, the entire contents of which is incorporated by reference herein. 
     With particular reference to  FIG. 7 , to help ensure that contact is maintained between follower  75  and a proximal cam surface  142   a , and between cam follower  65  and a distal cam surface  148   a  (e.g., to account for manufacturing tolerances, and/or to allow greater manufacturing tolerances, thus reducing costs), surgical forceps  10  may include an engagement spring  180  disposed between a proximal wall  64   c  of mandrel  64  and cam follower  65 . Engagement spring  180  is configured to urge cam follower  65  proximally toward and into contact with distal cam surface  148   a . Engagement spring  180  may be cone-like (e.g., frusto-conical) in shape, or a so-called Belleville washer. 
     With particular reference to  FIGS. 8-12 , an additional embodiment of surgical forceps is shown and is indicated by reference character  2000 . Surgical forceps  2000  is similar to surgical forceps  10  discussed above and only the differences are discussed in detail herein. 
     Surgical forceps  2000  includes a movable handle  2030   a  and a finger loop  2030   b . In lieu of finger loop  2030   b , surgical forceps  2000  may include a second movable handle. Handle  2030   a  includes an extension  2032  having a groove or channel  2040  defined therein. A roller  2050  is movably positioned within channel  2040 . 
     More particularly, channel  2040  extends within extension  2032  of handle  2030   a  and is defined by a proximal wall  2042  and a distal wall  2044  ( FIG. 11 ). The shape of channel  2040  is arcuate when used with a pivoting handle  2030   a ; channel  2040  may be linear when used with a non-pivoting handle (not shown). Channel  2040  includes a width “wc” ( FIG. 12 ) which may be uniform along its entire length or which may vary along at least a portion of its length. 
     Roller  2050  is supported by a support  2060 . Support  2060  is fixed to housing  2002  of surgical forceps  2000  and includes a pin  2062  extending through a leg  2064  of support  2060 . Pin  2062  rotationally supports roller  2050 . Roller  2050  is longitudinally fixed with respect to housing  2002  and is configured to engage channel  2040  of extension  2032 . Roller  2050  includes a width in the longitudinal direction. The width of roller  2050  is smaller than width “wc” of channel  2040 , thus enabling roller  2050  to move within channel  2040 . 
     As handle  2030   a , and thus extension  2032 , is moved, roller  2050  moves within channel  2040 . More particularly, as handle  2030   a  is moved, roller  2050  contacts proximal wall  2042  and distal wall  2044  of channel  2040 . For example, when handle  2030   a  is moved generally downward (as viewed in  FIG. 8 ) to approximate the jaw members, for instance, roller  2050  may contact distal wall  2044  of channel  2040 ; when handle  2030   a  is moved generally upward (as viewed in  FIG. 8 ) to move the jaw members to the open position, for example, roller  2050  may contact proximal wall  2042  of channel  2040 . Thus, channel  2040  provides support to roller  2050  at all times during manipulation of the jaw members, e.g., to restrict or minimize unintended bending motion. 
     The difference between the width of roller  2050  and the width “wc” of channel  2040  determines the amount of travel or “play” that handle  2030   a  can undergo while being actuated; a small difference between these distances results in a lower amount of “play.” 
     Surgical forceps  10 ,  2000  may also include features to help maintain the handle(s) in the closed position, and may include features for providing feedback to the user at certain stages of approximating or opening the jaw members. Such features are described in U.S. Provisional Patent Application Ser. No. 62/247,279, filed on Oct. 28, 2015, the entire contents of which have been incorporated by reference hereinabove. 
     The present disclosure also includes methods of manipulating jaw members  110 ,  120  using fine and gross controls, as described above. For example, disclosed methods include moving handle  30   a ,  30   b  of surgical instrument  10  from a non-actuated position a first distance to an intermediate position to cause first jaw member  110  to move a first amount, and moving handle  30   a ,  30   b  from the intermediate position a second distance to a fully actuated position to cause first jaw member  110  to move a second amount. Here, the first distance is the same as the second distance, and the first amount is less than the second amount, thus resulting in an initial fine movement of jaw member  110 , and a subsequent gross movement of jaw member  110 . 
     With particular reference to  FIGS. 13-16 , details of a second type of trigger assembly  200  are shown. Trigger assembly  200  of this embodiment includes a trigger  210 , a gear assembly  220 , a drive spool  230 , a knife slider  240 , a roller  250 , and a flexible drive member  260 . As discussed below, actuation of trigger assembly  200  is configured to longitudinally translate a drive member (e.g., a knife drive shaft  244 ). Additionally, while trigger assembly  200  is shown used in connection with a particular surgical forceps  2000 , trigger assembly  200  may also be used in connection with surgical forceps  10 , or an additional type of surgical device. 
     With particular reference to  FIGS. 14 and 15 , trigger  210  includes an actuation portion  212  configured for direct engagement by the user (e.g., physician), a plurality of trigger teeth  214 , and is rotatable about a trigger pin  216 . Gear assembly  220  (e.g., a cluster gear) includes a first gear  222  having a plurality of teeth  223 , and a second gear  224  having a plurality of teeth  225 . First gear  222  and second gear  224  are rotationally fixed with respect to each other, and are rotatable about a gear pin  226 . 
     Drive spool  230  includes a spool gear  232  having a plurality of teeth  234  (see  FIG. 16 ), and spool portion  236 . Drive spool  230  is rotatable about a spool pin  238 . A knife ring  242  is rotationally disposed within a portion of knife slider  240 . Knife ring  242  is rotatable about the longitudinal axis “X” with respect to knife slider  240 . Roller  250  is rotatable about a roller pin  252 . Flexible drive member  260  is in contact with spool portion  236  of drive spool  230 , knife slider  240 , and roller  250 . Flexible drive member  260  can be made from any suitable material such as nylon, a para-aramid synthetic fiber (e.g., Kevlar®), high-modulus polyethylene (HMPE), etc. for example. Flexible drive member  260  can also be made from plastic, e.g., having a rectangular cross-section (such as a zip-tie). In such embodiments, the pushing of various elements may be facilitated due to the strength of plastic. Additionally, assembly of surgical forceps  2000  may be facilitated using a plastic flexible drive member  260 , for example, as fewer loops may be necessary to accomplish each desired action (e.g., proximal and distal translation of knife slider  240 . 
     Details regarding the various interactions between the components of trigger assembly  200  are discussed herein with continued reference to  FIGS. 13-16 . Trigger teeth  214  of trigger  210  engage or mesh with teeth  223  of first gear  222  of gear assembly  220 . Accordingly, movement of actuation portion  212  in the general direction of arrow “A” in  FIGS. 13 and 14  causes rotation of trigger teeth  214  about trigger pin  216  in the general direction of arrow “B” in  FIGS. 13 and 14 , which causes rotation of first gear  222  about gear pin  226  in the general direction of arrow “C” in  FIGS. 13 and 14 . 
     First gear  222  of gear assembly  220  is rotationally fixed with respect to second gear  224  of gear assembly  220 . Teeth  225  of second gear  224  of gear assembly  220  engage or mesh with teeth  234  of spool gear  232  of drive spool  230 . Accordingly, rotation of first gear  222  about gear pin  226  in the general direction of arrow “C” causes rotation of second gear  224  about gear pin  226  in the general direction of arrow “C,” which causes rotation of spool gear  232  and drive spool  230  about spool pin  238  in the general direction of arrow “D” in  FIGS. 13 and 14 . Spool portion  236  of drive spool  230  is rotationally fixed with respect to spool gear  232 , such that rotation of spool gear  232  causes a corresponding rotation of drive spool  230 . 
     Flexible drive member  260  extends at least partially around spool portion  236  of drive spool  230 , extends at least partially around roller  250 , and is engaged with (e.g., wrapped around) a portion of knife slider  240 . Flexible drive member  260  is longitudinally fixed with respect to knife slider  240 . Accordingly, rotation of spool portion  236  of drive spool  230  in the general direction of arrow “D” causes translation of flexible drive member  260  in the general direction of arrow “E” in  FIGS. 13 and 14 , which causes roller  250  to rotate about roller pin  252  in the general direction of arrow “F” in  FIGS. 13 and 14 . Additionally, based on the way flexible drive member  260  engages a portion of knife slider  240  (as shown in  FIG. 15 ), translation of flexible drive member  260  in the general direction of arrow “E” causes knife slider  240  to move in the general direction of arrow “G” (or distally) in  FIGS. 13 and 14 . 
     Further, and with continued reference to  FIG. 16 , knife slider  240  includes a cutout  241  that rotationally supports knife ring  242 , such that knife ring  242  is rotatable about the longitudinal axis “X” with respect to knife slider  240  and with respect to trigger  210 , for example. Additionally, knife ring  242  is pinned to a knife drive shaft  244  and to drive bar  62  by a ring pin  243 , such that rotation of rotating assembly  80  causes rotation of drive bar  62  and knife ring  242  about the longitudinal axis “X” with respect to knife slider  240 . Moreover, ring pin  243  extends through a longitudinal slot  63  of drive bar  62 . Thus, longitudinal translation of knife slider  240  causes a corresponding longitudinal translation of knife ring  242  and knife drive shaft  244 . 
     Accordingly, actuation of trigger  210  in a first direction (e.g., in the general direction of arrow “A”) causes rotation of gear assembly  220 , rotation of drive spool  230 , movement of flexible drive member  260  around spool portion  236  of drive spool  230  and around roller  250 , which causes distal translation or advancement of knife slider  240 , knife ring  242  and knife drive shaft  244  to cut tissue, for example. Additionally, movement of trigger  210  in a second direction (e.g., in the general opposite direction of arrow “A”) causes proximal translation or retraction of knife drive shaft  244 . 
     Additionally, while the illustrated embodiments depict one type of surgical instrument (i.e., surgical forceps), the present disclosure includes the use of various features described herein in connection with other types of surgical devices including at least one pivotable handle or lever. For instance, various handle assemblies for actuating handle(s) and corresponding drive assemblies are contemplated for translating drive bar  62  and are discussed in commonly-owned U.S. Pat. No. 7,857,812, the entire contents of which are incorporated by reference herein. 
     Additionally, further details of a surgical forceps having a similar handle assembly to the disclosed handle assembly 30 are disclosed in U.S. Pat. No. 8,430,876, the entire contents of which being incorporated by reference herein. Further details of an electrosurgical instrument are disclosed in U.S. Pat. Nos. 7,101,371 and 7,083,618, the entire contents of which being incorporated by reference herein. 
     The various embodiments disclosed herein may also 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. 
     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 prepare the patient for surgery and configure the robotic surgical system with one or more of the surgical instruments disclosed herein while another surgeon (or group of surgeons) remotely controls the instrument(s) 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. 
     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). 
     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. 
     With particular reference to  FIG. 17 , 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 person (not shown), for example a surgeon, may be able to telemanipulate robot arms  1002 ,  1003  in a first operating mode. 
     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. 
     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 surgical instrument  10  (including end effector  300 ) 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. 
     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. 
     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. 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.