Patent Publication Number: US-2021177498-A1

Title: Apparatus for performing an electrosurgical procedure

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/435,632, filed on Jun. 10, 2019, which is a continuation of U.S. patent application Ser. No. 15/194,171, filed on Jun. 27, 2016, now U.S. Pat. No. 10,314,646, which is a continuation of U.S. patent application Ser. No. 14/035,423, filed on Sep. 24, 2013, now U.S. Pat. No. 9,375,227, which is a divisional of U.S. patent application Ser. No. 12/792,330, filed Jun. 2, 2010, now U.S. Pat. No. 8,540,749. 
    
    
     INTRODUCTION 
     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. 
     BACKGROUND 
     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. 
     SUMMARY 
     The present disclosure provides an endoscopic forceps. The endoscopic forceps includes a housing having a shaft that extends therefrom having a longitudinal axis defined therethrough. An end effector assembly operatively connects to a distal end of the shaft and includes a pair of first and second jaw members. One or both of the first and second jaw members is movable relative to the other jaw member from an open position to a clamping position. One of the first and second jaw members includes one or more cam slots defined therein and is configured to receive a cam member that upon movement thereof rotates the jaw members from the clamping position to the open position. A resilient member is operably coupled to one or both of the jaw members. The resilient member is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween. 
     The present disclosure provides an endoscopic forceps. The endoscopic forceps includes a housing having a shaft that extends therefrom having a longitudinal axis defined therethrough. An end effector assembly operatively connects to a distal end of the shaft and includes a pair of first and second jaw members. The first and second jaw members each having a respective detent operably disposed at a proximal end thereof. The first and second jaw members movable relative to one another 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 cam assembly is movable along the longitudinal axis and includes one or more cam slots defined therein. The one or more cam slots are configured to receive the detent associated with the respective first and second jaw members. A resilient member operably couples to the cam assembly and is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween. 
     The present disclosure provides an endoscopic forceps. The endoscopic forceps includes a housing having a shaft that extends therefrom having a longitudinal axis defined therethrough. An end effector assembly operatively connects to a distal end of the shaft and includes a pair of first and second jaw members. One or both of the first and second jaw members is movable relative to the other jaw member that is stationary from an open position to a clamping position. A support member is operably disposed at a distal end of the shaft adjacent the end effector. A resilient member in mechanical communication with the support member operably couples to the first and second jaw members. The resilient member is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween. 
     In embodiments, a plurality of non-conductive stop members is disposed on an inner facing surface of one or both of the first and second jaw members. The stop members are configured to maintain a uniform distance between the first and second jaw members along the length thereof during tissue sealing. 
     The present disclosure also provides a method for performing a laparoscopic surgical procedure. The method includes providing an endoscopic instrument that includes an end effector assembly including a pair of first and second jaw members. One or both of the first and second jaw members is movable relative to the other from a clamping position to an open position. The movable jaw member includes one or more cam slots defined therein that is configured to receive a cam member. A resilient member is operably coupled to one or both of the first and second jaw members. The resilient member is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween. A step of the method includes biasing the first and second jaw members in the clamping position with the resilient member for positioning the end effector adjacent to tissue. Moving the movable jaw member to the open position is a step of the method. Positioning tissue between the first and second jaw members is another step of the method. And, moving the movable jaw member to the clamping position is still yet another step of the method. 
    
    
     
       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 in a closed configuration 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 of a handle assembly associated with the endoscopic bipolar forceps; 
         FIG. 2  is a schematic view of the jaw members depicted in  FIGS. 1A and 1B  operably coupled to a jaw housing associated with each of the jaw members; 
         FIGS. 3A and 3B  are schematic views of jaw members operably coupled to a distal end of the endoscopic forceps depicted in  FIGS. 1A and 1B  according to another embodiment of the present disclosure; 
         FIGS. 4A and 4B  are schematic views of jaw members operably coupled to a distal end of the endoscopic forceps depicted in  FIGS. 1A and 1B  according to yet another embodiment of the present disclosure; and 
         FIG. 5  is a side, perspective view of an endoscopic bipolar forceps showing an end effector assembly including jaw members in an open configuration according to still 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. 
     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 a suitable power source, such as, for example, 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 generator may be configured for monopolar and/or bipolar modes of operation. The generator may include or is in operative communication with a system (not shown) that may include one or more processors in operative communication with one or more control modules that are executable on the processor. The control module (not explicitly shown) 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., a cable  23 ) to the forceps  10 . 
     Forceps  10  is shown configured for use with various electrosurgical procedures and generally includes a housing  20 , electrosurgical cable  23  that connects the forceps  10  to a source of electrosurgical energy (e.g., the electrosurgical generator), a handle assembly  30 , a rotating assembly  80 , a trigger assembly  70 , a drive assembly  130  (see  FIG. 1B ), and an end effector assembly  100  that operatively connects to a drive element  150  of the drive assembly  130 . End effector assembly  100  includes opposing jaw members  110  and  120  ( FIGS. 1A and 1B ) that mutually cooperate to grasp, seal and, in some cases, divide large tubular vessels and large vascular tissues. The drive assembly  130  is in operative communication with handle assembly  30  for imparting movement of one or both of a pair of jaw members  110 ,  120  of end effector assembly  100 . Conventional drive 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 . 
     With continued reference to  FIGS. 1A and 1B , forceps  10  includes a shaft  12  that has a distal end  14  configured to mechanically engage the end effector assembly  100  and a proximal end  16  that mechanically engages the housing  20 . In the drawings and in the descriptions that follow, the term “proximal,” as is traditional, will refer to the end of the forceps  10  which is closer to the user, while the term “distal” will refer to the end that is farther from the user. 
     Handle assembly  30  includes a fixed handle  50  and a movable handle  40 . Fixed handle  50  is integrally associated with housing  20  and handle  40  is movable relative to fixed handle  50 . Movable handle  40  of handle assembly  30  is ultimately connected to the drive assembly  130 , which together mechanically cooperate to impart movement of one or both of the jaw members  110  and  120  to move from a clamping or closed position ( FIG. 1A ), wherein the jaw members  110  and  120  cooperate to grasp tissue therebetween, to an open position ( FIG. 1B ), wherein the jaw members  110  and  120  are disposed in spaced relation relative to one another. 
     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 , described in greater detail below. For the purposes herein, jaw members  110  and  120  include jaw housings  117  and  127  that are configured to support sealing plates  118  and  128 , respectively. 
     For a more detailed description of the forceps  10  including handle assembly  30  including movable handle  40 , rotating assembly  80 , trigger assembly  70 , drive assembly  130 , jaw members  110  and  120  (including coupling methods utilized to pivotably couple the jaw members  110  and  120  to each other) and electrosurgical cable  23  (including line-feed configurations and/or connections), reference is made to commonly owned U.S. Pat. No. 7,766,910 filed on Nov. 9, 2006. 
     Turning now to  FIG. 2 , one embodiment of jaw housings  117  and  127  is shown. It should be noted that in accordance with the present disclosure one or both of the jaw housings  117  and  127  may include a proximal end that is configured to support one or more cam slots  202  and resilient members  204  to facilitate closing in of the jaw members  110  and  120 . Jaw members  110  and  120  are substantially identical to each other, and, in view thereof, and so as not to obscure the present disclosure with redundant information, the operative components associated with the jaw housing  117  are described in further detail with respect to jaw member  110 , and only those features distinct to jaw member  120  and jaw housing  127  will be described hereinafter. 
     With continued reference to  FIG. 2 , jaw member  110 , jaw housing  117 , and operative components associated therewith may be formed from any suitable material, including but not limited to metal, metal alloys, plastic, plastic composites, etc. In the embodiment illustrated in  FIG. 2 , jaw member  110  is formed from metal. 
     A distal end  117   a  of the jaw housing  117  of jaw member  110  is configured to securely engage the electrically conductive seal plate  118 . A portion of a proximal end  117   b  of the jaw member  110  is operably secured to the distal end  14  of the shaft  12 . More particularly, a portion of proximal end  117   b  operably couples to the distal end  14  and is in operative communication with the drive element  150  of the drive assembly  130  such that movement of the drive element  150  causes one or both of the jaw members  110  and  120  to move from the closed or clamping position to the open position and vice versa. For example, in one particular embodiment, when the drive element  150  is “pulled,” i.e., moved or translated proximally, one or both of the jaw members  110  and  120  is/are caused to move away from the other. Alternatively, and if desired, the drive assembly  130  including the drive element  150  may be configured such that when the drive element  150  is “pushed,” i.e., moved or translated distally, one or both of the jaw members  110  and  120  are caused to move away from each other. In certain instances, it may prove useful to have a drive element  150  that is flexible. More particularly, where the drive element  150  is operatively associated with an endoluminal instrument the drive element  150  may be substantially flexible to accommodate bends typically associated with that type of instrument when the bipolar forceps  10  is remotely actuatable relative to the patient. 
     In the illustrated embodiment, proximal end  117   b  of the jaw housing  110  includes a generally elongated configuration that may be rectangular, circumferential or combination thereof in shape. 
     Proximal end  117   b  of the jaw member  110  includes one or more cam slots  202  defined therein that support one or more cam members  205  (see  FIG. 2 ). More particularly, cam slot  202  is of suitable proportion and configured to receive cam member  205  and is operably formed and/or positioned at the proximal end  117   b  of the jaw housing  117 . Cam slot  202  includes a generally oblique configuration with respect to a longitudinal axis “B-B” that is parallel to a longitudinal axis “A-A” defined through the shaft  12 , see  FIGS. 1A and 2 . Cam slot  202  may extend at an angle that ranges from about 5° to about 30° with respect to the longitudinal axis “B-B.” In the embodiment illustrated  FIG. 2 , cam slot  202  extends at an angle that is approximately equal to 45° with respect to the longitudinal axis “B-B.” The angle of the cam slot  202  may be selectively varied depending upon a particular instrument, use or manufacturing preference. 
     An opening  208  is defined in and extends through the jaw housing  117   b  and is configured to receive a spring pin  211 . Opening  208  is shown engaged with spring pin  211  and as such is not explicitly visible. In the embodiment illustrated in  FIG. 2 , a portion of the spring pin  211  is dimensioned to securely engage the resilient member  204 . 
     One or more types of resilient members  204  may be operably associated with the housing  117  and includes, for example, a torsion spring that is utilized to generate a closure force on the jaw members  110  and  120  when the jaw members  110  and  120  are in a closed or clamped position. The resilient member  204  cooperates with the drive assembly  130  to provide the necessary closure force on the jaw members  110  and  120  for sealing tissue, e.g., in the range of about 3 kg/cm 2  to about 16 kg/cm 2 . 
     Resilient member  204  operably engages jaw housings  117  and  127  and is biased in a closed orientation. More particularly, a proximal end  212  of suitable proportion and having a generally circumferential configuration is dimensioned to securely couple to the spring pin  211 . Two generally elongated fingers  214  and  216  extend from proximal end  212  adjacent the proximal ends of the jaw members, e.g., proximal end  117   b  of jaw member  110  and a proximal end (not explicitly shown) of the jaw member  120 , and fixedly couple to a respective distal end of the jaw member, e.g., distal end  117   a  of jaw member  117  and a distal end  127   a  of the jaw member  120 . In the embodiment illustrated in  FIG. 2 , the resilient member  204  biases the jaw members  110  and  120  toward each other to a closed position such that a consistent uniform seal is effected to tissue. More particularly, the configuration of the resilient member  204  is designed such that each the elongated fingers  214  and  216  are operably disposed adjacent a respective imaginary center-line “CL” that extends through each of the jaw members  110  and  120 , see  FIG. 2 . In this instance, the force from each of the elongated fingers  214  and  216  is evenly distributed to and throughout a respective jaw member. 
     One or more types of lubricious materials (not shown), e.g., PTFE, may coat cam slot  202  or an inner peripheral surface thereof. Coating the cam slot  202  with the lubricious material facilitates movement of the cam member  205  within the cam slot  202  when the drive element  150  is translated proximally (or distally depending on a particular configuration). 
     In an assembled configuration each of the jaw members  110  and  120  are positioned in side-by-side relation. Cam member  205  is operably disposed within cam slot  202  associated with jaw member  110  and a corresponding cam slot (not explicitly shown) associated with jaw member  120 . Spring pin  211  is positioned within the opening associated with jaw member  110  and a corresponding opening (not explicitly shown) associated with jaw member  120 . As noted above, the spring pin  211  provides a point of pivot for each of the jaw members  110  and  120 . Once assembled, the jaw members  110  and  120  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. Patent Publication No. 2007/0260242 filed on Jul. 11, 2007. 
     In use, initially jaw members  110  and  120  are biased in a closed position under the closure and/or sealing force provided by the resilient member  204 . Proximal movement of movable handle  40  causes the drive element  150  to move proximally. Proximal movement of the drive element  150  causes cam member  205  positioned within the cam slot  202  to move proximally against the bias of the resilient member  204 , which, in turn, causes both of the jaw members  110  and  120  to move relative to one another, such that tissue is positioned between the jaw members  110  and  120 . Once tissue is positioned between the jaw members  110  and  120  the movable handle  40  is released, which, in turn, causes the jaw members  110  and  120  to move toward one another under the biasing force of the resilient member  204  which generates a sealing or closure force on the tissue disposed between the jaw members  110  and  120 . The resilient member  204  provides an additional mechanical advantage at the jaw members  110  and  120  and reduces 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, e.g., the closure force is offloaded and/or diminished by the resilient member  204 . 
     With reference to  FIGS. 3A and 3B , another embodiment of an end effector  300  that is configured for use with the forceps  10  is illustrated. End effector  300  is substantially identical to end effector  100 , and, in view thereof, and so as not to obscure the present disclosure with redundant information, and only those features distinct to end effector  300  will be described hereinafter. 
     End effector  300  includes jaw members  310  and  320 . As described above with respect to jaw members  110  and  120 , jaw members  310  and  320  are pivotably coupled to each other via a spring pin or pivot pin  311 . More particularly, pivot pin  311  operably couples the jaw members  310  and  320  about a medial portion of a respective jaw housing  317  and  327  ( FIG. 3A ). Pivot pin  311  maintains the jaw members  310  and  320  in a substantially fixed position with respect to the longitudinal axis “A-A” when the jaw members  310  and  320  are pivoting or rotating about the pivot pin  311 . That is, the jaw members  310  and  320  do not translate along the longitudinal axis “A-A” when movable handle  40  is moved. 
     A respective detent  313  and  323  is operably disposed at a respective proximal end  317   b  and  327   b  of the jaw members  310  and  320 , respectively. In the embodiment illustrated in  FIGS. 3A and 3B , the detents  313  and  323  are configured to rotate the respective jaw members  310  and  320  from an open position ( FIG. 3A ) to a closed or clamping position ( FIG. 3B ) when the movable handle  40  is moved proximally. Detents  313  and  323  are proportioned to movably couple to a cam assembly  330 . 
     Cam assembly  330  translates or moves along the longitudinal axis “A-A” when the movable handle  40  is moved proximally and/or distally. To this end, cam assembly  330  is suitably shaped and proportioned to movably reside within the shaft  12  adjacent the distal end  14 . For illustrative purposes, cam assembly  330  is shown elongated with a generally rectangular shape. One or more cam slots  332  are operably disposed on or defined in the cam assembly  330 . In the embodiment illustrated in  FIGS. 3A and 3B , two intersecting cam slots  332   a  and  332   b  are defined in the cam assembly  330 . The cam slots  332   a  and  332   b  are proportioned to receive a respective detent  313  and  323  such that the detents  313  and  323  are movable along a length of the respective cam slots  332   a  and  332   b.    
     Each of the cam slots  332   a  and  332   b  includes a respective distal end  334  and  336 . The distal ends  334  and  336  are configured to function as latches. More particularly, the distal ends  334  and  336  maintain the respective detents  313  and  323  in a substantially fixed position after the movable handle  40  is moved a predetermined distance proximally and the jaw members  310  and  320  are in the clamping position. 
     One or more suitable unlatching devices or configurations may be utilized to unlatch the detents  313  and  323  from the respective distal ends  334  and  336 . For example, and in one particular embodiment, one or more detents  335  may be operably disposed along an internal surface of the shaft  12 . In this instance, the detent  335  may be configured to contact a portion, e.g., a bottom surface  331 , of the cam assembly  330  when the movable handle  40  is moved through an “unlatching” stroke, see  FIGS. 3A and 3B . Accordingly, when movable handle  40  is moved through the “unlatching” stroke, the detent  335  contacts the bottom surface  331  of the cam assembly  330 , which, in turn, unlatches the detents  313  and  323  from the respective distal ends  334  and  336 . Other latching and unlatching devices and/or configurations may be utilized to latch and unlatch the detents  313  and  323  from the respective distal ends  334  and  336 . 
     One or more types of resilient members  304  operably couple to the drive element  150  and to the cam assembly  330 . Resilient member  304  may be any suitable resilient member, e.g., a compression spring. A distal end of the drive element  150  operably couples to a proximal end of the resilient member  304  and proximal end of the cam assembly  330  operably couples to a distal end of the resilient member  304 . The resilient member  304  operably couples to the distal end of the drive element  150  and proximal end of the cam assembly  330  via any suitable coupling methods. As described above with resilient member  204 , resilient member  304  cooperates with the drive assembly  130  to provide the necessary closure force on the jaw members  310  and  320  for sealing tissue, e.g., in the range of about 3 kg/cm 2  to about 16 kg/cm 2 . 
     In use, initially jaw members  310  and  320  are biased in an open position ( FIG. 3A ). Tissue is positioned between the jaw members  310  and  320 . Thereafter, the movable handle  40  is moved proximally causing the drive element  150  to move proximally. Proximal movement of the drive element  150  moves the resilient member  304  proximally, which, in turn, moves the cam assembly  330  proximally. Proximal movement of the cam assembly  330  causes the detents  313  and  323  to move within the respective cam slots  332   a  and  332   b  and to the respective distal ends  334  and  336  until the detents  313  and  323  are latched into a closed or clamping position ( FIG. 3B ). In the latched position, the requisite sealing or closure force is present on the tissue disposed between the jaw members  310  and  320 . Thereafter, electrosurgical energy is transmitted to seal surfaces  318  and  328  operably associated with respective jaw members  310  and  320  such that a desired tissue effect, e.g., a tissues seal, may be achieved on the tissue disposed between the jaw members  310  and  320 . To open the jaw members  310  and  320 , the moveable handle  40  is moved through an “unlatching” stroke that unlatches or releases the detents  313  and  323  from the respective distal ends  334  and  336  such that the jaw members  310  and  320  return to the initial open position. 
     With reference to  FIGS. 4A and 4B , an end effector  400  that is configured for use with the forceps  10  is illustrated. End effector  400  is substantially identical to end effectors  100  and  300 , and, in view thereof, and so as not to obscure the present disclosure with redundant information, only those features distinct to end effector  400  will be described hereinafter. 
     End effector  400  includes jaw members  410  and  420 . In the embodiment illustrated in  FIGS. 4A and 4B , one of the jaw members, e.g., jaw members  420 , is movable, and one of the jaw members, e.g., jaw member  410 , is stationary. This configuration of jaw members  420  and  410  may be reversed to accommodate various surgical procedures. Jaw members  410  and  420  are pivotably coupled to one another via a pivot pin  411 . 
     A support structure or member  430  is operably disposed along an internal frame of the shaft  12  adjacent the distal end  14 . More particularly, the support structure  430  is operably coupled to a top portion of the internal frame of the shaft  12 . Support structure  430  is configured to mechanically communicate with a resilient member  404 . More particularly, the support structure  430  provides a substantially rigid surface that is configured to compress the resilient member  404  when the resilient member  404  is moved proximally and the movable jaw member  420  is moved to the open position. To this end, support structure  430  may have any suitable shape. In the embodiment illustrated in  FIGS. 4A and 4B , support structure  430  includes a generally circumferential configuration having an aperture  406  of suitable proportion defined therethrough. Aperture  406  is includes a diameter that is sized to receive the drive element  150  (or portion thereof) that includes a distal end that operably couples to a proximal end  427   b  of the movable jaw member  420 . More particularly, the diameter of the aperture  406  is such that the drive element  150  is movable through the aperture  406  when the movable handle  40  is moved proximally and/or distally. Additionally, the aperture  406  is proportioned such that the resilient member  404  is prevented from translating therethrough when the movable handle  40  is moved proximally and/or distally. 
     In the embodiment illustrated in  FIGS. 4A and 4B , the support structure  430  is configured to maintain the drive element  150  in a substantially fixed off-set orientation above the pivot pin  411 , see  FIG. 4A , for example. Having the support structure  430  configured in such a manner facilitates moving the jaw member  420  about the pivot pin  411 . 
     Resilient member  404  is operably disposed between the support structure  430  and the proximal end  427   b  of the jaw housing  427 . In an uncompressed state, resilient member  404  cooperates with the support structure  430  to provide the necessary closure force on the jaw members  410  and  420  for sealing tissue, e.g., in the range of about 3 kg/cm 2  to about 16 kg/cm 2 . To this end, the resilient member  404  may be any suitable resilient spring, e.g., a compression spring  404 , including, but not limited to those previously described herein. The compression spring  404  is proportioned such that the drive element  150  is positionable therethrough,  FIG. 4A . 
     In use, initially jaw members  410  and  420  are biased in a closed position under the closure and/or sealing force provided by the compression spring  404  ( FIG. 4B ). Proximal movement of movable handle  40  causes the drive element  150  to move proximally. Proximal movement of the drive element  150  causes the moveable jaw member, e.g., jaw member  420 , to move relative to the stationary jaw member, e.g., jaw member  410 , such that tissue is positioned between the jaw members  410  and  420 . Once tissue is positioned between the jaw members  410  and  420  the movable handle  40  is released, which, in turn, causes the jaw member  420  to move toward jaw member  410  under the biasing force of the compression spring  404  which generates a sealing or closure force on the tissue disposed between the jaw members  410  and  420 . The compression spring  404  provides an additional mechanical advantage at the jaw members  410  and  420  and reduces 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, e.g., the closure force is offloaded and/or diminished by the compression spring  404 . 
     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, other resilient members, e.g., leaf springs, compressed gas, resilient bladder, spring washers and bellows, may be operably associated with any of the aforementioned configurations of utilized to generate a closure or sealing force at the jaw members. Moreover, the resilient members  204 ,  304  and  404  may work in combination with one or more springs located with the shaft  12  or housing  20  that are operatively associated with the drive assembly  130  to generate the necessary forces associated with tissue sealing. 
     As best seen in  FIG. 5 , in order to achieve a desired spacing between the electrically conductive surfaces of the respective jaw members, e.g., jaw members  110  and  120 , (i.e., gap distance) and apply a desired force to seal the tissue, one or both of the jaw member  110  and/or  120  may include one or more stop members  350  that limit the movement of the two opposing jaw members  110  and  120  relative to one another. The stop member  350  may be disposed on an inner facing surface of one or both of the jaw members  110  and  120 . More particularly, stop member  350  extends from a seal surface  118   a  of seal plate  118  a predetermined distance according to the specific material properties (e.g., compressive strength, thermal expansion, etc.) to yield a consistent and accurate gap distance during sealing. In the illustrated embodiment, the stop members  350  extend from the seal surfaces  118   a  and  128   a  a distance that ranges from about 0.001 inches to about 0.006 inches. The gap distance between opposing sealing surfaces  118   a  and  128   a  during sealing may range from about 0.001 inches to about 0.006 inches and, preferably, between about 0.002 and about 0.003 inches. The configuration of a seal surface  118   a  with stop members  350  facilitates in maintaining a uniform distance between the jaw members  110  and  120  along the length thereof during tissue sealing. 
     For a more detailed description of the stop members  350  and operative components associated therewith, reference is made to commonly-owned U.S. Pat. No. 8,241,284. 
     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.