Patent Publication Number: US-10772632-B2

Title: Surgical stapling device with triple leg staples

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to surgical staplers and, more particularly, to surgical staplers for endoscopic use. The present disclosure also relates to triple leg staples for use with endoscopic surgical staplers. 
     2. Background of Related Art 
     Surgical staplers typically include a cartridge housing a plurality of staples, an anvil for forming the staples as the staples are ejected from the cartridge, and a knife to effect simultaneous dissection and suturing of tissue. When compared to applying manually threaded sutures, the use of surgical staplers to suture and dissect tissue has increased the speed of the surgical procedure and thus, minimized patient trauma. 
     In an endoscopic surgical procedure, a surgical stapler is inserted through a small incision in the skin or through a cannula to access a surgical site. Due to the complexity of known surgical staplers as well as the staple size requirements of known staple forming apparatus, a continued need exists for small diameter surgical staplers suitable for endoscopic use. 
     SUMMARY 
     The present disclosure is directed to a surgical stapling device having a tool assembly including an anvil assembly and a cartridge assembly having a series of triple leg staples which are supported and configured to be rotatably ejected from the cartridge assembly into the anvil assembly to suture tissue. The manner in which the staples are supported and ejected from within the staple cartridge facilitates the use of a tool assembly of reduced diameter that includes staples capable of suturing thicker tissues than would normally be associated with tool assemblies with such a reduced diameter. 
     The present disclosure is also directed to a triple leg staple that can be ejected from the presently disclosed surgical stapling device. In embodiments, the triple leg staple includes three legs of different lengths. Each of the legs is configured to provide a different degree of compression when applied to tissue. In addition, each of the staple legs has a D-shaped configuration when deformed. 
     In one aspect of the present disclosure, a surgical stapling device includes a shaft portion and a tool assembly supported on a distal end of the shaft portion. The tool assembly includes an anvil assembly and a cartridge assembly. The cartridge assembly includes a cartridge body defining a plurality of pockets and at least three longitudinal channels and a plurality of staples supported with the cartridge body. Each of the staples has a first leg, a second leg and a third leg of different lengths. The first and second legs are interconnected by a backspan and the third leg being secured to the backspan. The backspan of each of the staples is rotatably supported within a respective one of the pockets. A sled includes a plurality of firing cams. Each of the firing cams is positioned to engage one of the first, second, or third legs of the plurality of staples. The sled is movable through the cartridge body to rotate and eject the plurality of staples from the cartridge assembly. 
     In embodiments, the cartridge body defines a longitudinal knife slot and the at least three longitudinal channels includes three longitudinal channels positioned on a first side of the longitudinal knife slot and three longitudinal channels positioned on a second side of the longitudinal knife slot. 
     In some embodiments, the plurality of staples includes a first row of staples supported on the first side of the longitudinal slot and a second row of staples supported on the second side of the longitudinal slot. Each of the legs of the plurality of staples in the first row of staples is positioned in a respective one of the three longitudinal channels on the first side of the longitudinal knife slot, and each of the legs of the plurality of staples in the second row of staples is positioned in a respective one of the three longitudinal channels on the second side of the longitudinal knife slot. 
     In certain embodiments, the plurality of firing cams includes six firing cams, wherein each of the firing cams is positioned to translate through one of the longitudinal channels defined in the cartridge body. 
     In embodiments, the staple backspan includes a U-shaped portion and two linear portions and the third leg is secured to the U-shaped portion of the backspan. 
     In some embodiments, the U-shaped portion extends distally between the first and second legs and the third leg is rotatably supported to the distal end of the U-shaped portion of the backspan. 
     In certain embodiments, the two linear portions of the backspan are pivotally supported within the plurality of pockets. 
     In embodiments, each of the pockets includes a resilient retaining feature to secure the backspan within a respective pocket. 
     In some embodiments, a drive assembly includes a drive member and a working member secured to a distal end of the drive member, wherein the drive member has a proximal end adapted to engage an actuator device. 
     In certain embodiments, the working member includes an upper beam, a lower beam, and a vertical strut interconnecting the upper beam and the lower beam. The vertical strut has a cutting edge and is positioned to translate through the longitudinal knife slot. 
     In embodiments, the anvil assembly defines a channel that receives the upper beam and the cartridge assembly includes a cartridge channel that defines a longitudinal slot that receives the vertical strut, wherein the upper beam is movable along an outer surface of the cartridge channel to define a maximum tissue gap between the cartridge assembly and the anvil assembly. 
     In some embodiments, the third leg of each of the plurality of staples is axially offset from the first and second legs. 
     In certain embodiments, each of the plurality of firing cams includes a curved nose and a ramp, the curved nose being positioned to engage and rotate a respective one of the first, second, or third legs of the plurality of staples and the ramp being positioned to disengage the plurality of staples from the pockets of the cartridge body. 
     In embodiments, the ramp has a height greater than the height of the curved nose. 
     In another aspect of the disclosure, a surgical triple leg staple includes a first leg, a second leg, a third leg, and a backspan. Each of the first, second, and third legs are of different lengths. The first and second legs are interconnected by the backspan and the third leg is secured to the backspan. 
     In embodiments, the staple backspan includes a U-shaped portion and two linear portions, and the third leg is secured to the U-shaped portion of the backspan. 
     In some embodiments, the third leg is rotatably secured to the backspan. 
     In certain embodiments, the U-shaped portion extends distally between the first and second legs and the third leg is rotatably supported on the distal end of the U-shaped portion of the backspan. 
     In embodiments, the two linear portions of the backspan engage a proximal end of the first and second legs, respectively. 
     In some embodiments, the first and second legs are axially offset from the third leg. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the presently disclosed surgical stapling device are described herein with reference to the drawings, wherein: 
         FIG. 1  is a side perspective view of an embodiment of the presently disclosed surgical stapling device with the tool assembly in an open position; 
         FIG. 2A  is a side perspective view from the distal end of a stapler reload of the surgical stapling device shown in  FIG. 1 ; 
         FIG. 2B  is a side perspective view from the proximal end of the stapler reload shown in  FIG. 2 ; 
         FIG. 3  is a side perspective, exploded view of the stapler reload shown in  FIG. 2A ; 
         FIG. 4  is an enlarged view of the indicated area of detail shown in  FIG. 2A ; 
         FIG. 5  is an enlarged view of the indicated area of detail shown in  FIG. 8 ; 
         FIG. 6  is a cross-sectional view taken along section line  10 - 10  of  FIG. 8 ; 
         FIG. 7  is a side perspective view of two rows of triple leg staples of a cartridge assembly of the stapler reload shown in  FIG. 2A ; 
         FIG. 8A  is a side perspective view of a left sided triple leg staple of the stapler reload shown in  FIG. 2A ; 
         FIG. 8B  is a side perspective view of a right sided triple leg staple of the stapler reload shown in  FIG. 2A ; 
         FIG. 9A  is a side view of the left sided triple leg staple shown in  FIG. 8A ; 
         FIG. 9B  is a side view of the right sided triple leg staple shown in  FIG. 8B ; 
         FIG. 10A  is a top view of the left sided triple leg staple shown in  FIG. 8A ; 
         FIG. 10B  is a top view of the right sided triple leg staple shown in  FIG. 8B ; 
         FIG. 11  is a side perspective view from the distal end of a sled of the stapler reload shown in  FIG. 2 ; 
         FIG. 12  is a side perspective view from the proximal end of a sled of the stapler reload shown in  FIG. 2 ; 
         FIG. 13  is a side view of the sled shown in  FIG. 12 ; 
         FIG. 14  is a top view of the sled shown in  FIG. 12 ; 
         FIG. 15  is a front view of the sled shown in  FIG. 12 ; 
         FIG. 16  is a side perspective view of the anvil of the stapler reload shown in  FIG. 2A ; 
         FIG. 17  is an enlarged view of the indicated area of detail shown in  FIG. 16 ; 
         FIG. 18  is a cross-sectional view taken along section line  18 - 18  of  FIG. 2A ; 
         FIG. 19  is an enlarged view of the indicated area of detail shown in  FIG. 18 ; 
         FIG. 20  is a side cross-sectional view of the tool assembly of the stapler reload shown in  FIG. 2A  with the tool assembly in a clamped position; 
         FIG. 21  is a top view of the cartridge assembly of the tool assembly shown in  FIG. 20 ; 
         FIG. 22  is an enlarged view of the indicated area of detail shown in  FIG. 21 ; 
         FIG. 23  is an enlarged, perspective view of a portion of the cartridge assembly shown in  FIG. 21 ; 
         FIG. 24  is a cross-sectional view taken along section line  24 - 24  of  FIG. 21 ; 
         FIG. 25  is an enlarged view of the indicated area of detail shown in  FIG. 24 ; 
         FIG. 26  is an enlarged view of the indicated area of detail shown in  FIG. 25 ; 
         FIG. 27  is a cross-sectional view taken along section line  27 - 27  of  FIG. 21 ; 
         FIG. 28  is a cross-sectional view taken along section line  28 - 28  of  FIG. 21 ; 
         FIGS. 29A-31C  are side cross-sectional views of the tool assembly of the stapler reload shown in  FIG. 2  showing different stages of deformation of the legs of the triple leg staples; 
         FIG. 32  is a side perspective view of a deformed triple leg staple of the tool assembly shown in  FIG. 20 ; and 
         FIG. 33  is a side view of the tool assembly of an alternate embodiment of the stapler reloads shown in  FIG. 2  including a buttress material. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Embodiments of the presently disclosed endoscopic surgical stapler including triple leg staples for endoscopic use will now be described in detail with reference to the drawings wherein like reference numerals designate identical or corresponding elements in each of the several views. In this description, the term “proximal” is used generally to refer to the portion of the device that is closer to a clinician, while the term “distal” is used generally to refer to the portion of the device that is farther from the clinician. In addition, the term “endoscopic” is used generally to refer to endoscopic, laparoscopic, or arthroscopic devices or procedures as well as any other surgical device or procedure that is configured to extend or be performed through a small incision or a cannula inserted into a patient&#39;s body. Finally, the term “clinician” is used generally to refer to medical personnel including doctors, nurses, and support personnel. 
     The present disclosure is directed to a surgical stapling device having a tool assembly including an anvil assembly and a cartridge assembly having a series of triple leg staples which are supported and configured to be rotatably ejected from the cartridge assembly into the anvil assembly to suture tissue. The manner in which the staples are supported and ejected from within the cartridge assembly facilitates the use of a tool assembly of reduced diameter that includes staples capable of suturing thicker tissues than would normally be associated with tool assemblies with such a reduced diameter. 
     The present disclosure is also directed to a triple leg staple that can be ejected from presently disclosed surgical stapling device. In embodiments, the triple leg staple includes three legs of different lengths. Each of the legs is configured to provide a different degree of tissue compression when applied to tissue. In addition, each of the staple legs has a D-shaped configuration when deformed. 
       FIG. 1-2B  illustrate the presently disclosed surgical stapling device  10  which includes an actuating device  12  having a handle assembly  12   a , a body portion  14  that extends distally from the handle portion  12   a , and a stapler reload  100  supported on a distal end of the body portion  14 . The distal end of the body portion  14  is adapted to releasably engage a proximal end of the reload  100  such that actuation of the actuating device  12  effects operation of the reload  100 . Suitable actuating devices are disclosed in detail in U.S. Pat. No. 5,865,361 (“361 patent”) and U.S. Pat. No. 7,143,924 (“924 patent”) which are incorporated herein in their entirety by reference. Although the presently disclosed actuating device is illustrated as a manually actuated handle assembly, it is envisioned that other known actuating devices including robotic devices, motorized devices, and/or electrically or mechanically driven devices can be used to actuate the reload  100 . It is also envisioned that the presently disclosed surgical stapling device  10  and the reload  100  can be integrally formed such that the reload  100  is not separable from the actuating device  12 . 
     Referring to  FIGS. 2A-3 , the reload  100  includes a proximal body portion  110  and a tool assembly  114 . The proximal body portion  110  includes an inner housing  116  ( FIG. 18 ) including an upper housing half-section  116   a  and a lower housing half-section  116   b . The housing half-sections  116   a  and  116   b  define channels that slidably receive a drive member  118  and an articulation link  120 . The inner housing  116  is received within a proximal body tube  125 . 
     Referring to  FIG. 3 , the drive member  118  supports a drive coupler  123  that is adapted to engage a control rod (not shown) of the actuating device  12  ( FIG. 1 ) to operate the tool assembly  114  of the reload  100 . The articulation link  120  has a proximal end that is configured to engage an articulation link (not shown) of the actuating device  12  and a distal end pivotally connected to the tool assembly  114 . Operation of the drive coupler  123  and the articulation link  120  are described in the &#39;361 patent and will not be described in further detail herein. 
     A distal end of the drive member  118  is coupled to a working member  122  such as by welding to form a drive assembly  124 . Alternately, other securement techniques can be used to secure the distal end of the drive member  118  to the working member  122 . In one embodiment, the working member  122  includes an upper beam  126 , a lower beam  128  and a vertical strut  130  interconnecting the upper and lower beams  126  and  128 . A cutting edge  130   a  is formed or supported on a distal side of the vertical strut  130 . The vertical strut  130  is configured to translate through the tool assembly  114  when the tool assembly  114  is actuated by the actuating device  12  to fire the staples and dissect tissue as will be discussed in further detail below. 
     The tool assembly  114  includes an anvil assembly  132  and a cartridge assembly  134 . The anvil assembly  132  includes an anvil body  136  and an anvil plate  138 . The anvil body  136  and the anvil plate  138  are secured together such as by welding to define a channel  140  that is dimensioned to receive the upper beam  126  of the working member  122 . The anvil plate  138  includes a tissue contacting surface  142  ( FIG. 16 ) that defines a plurality of staple deforming recesses  144  as discussed in further detail below and a longitudinal knife slot  146  configured to receive an upper end of the vertical strut  130  such that the upper beam  126  is received in the channel  140 . 
     The cartridge assembly  134  includes a channel member  150 , a cartridge body  152 , and a plurality of triple leg staples  154 . The channel member  150  includes a pair of spaced sidewalls  156  that define openings or recesses  158 . The cartridge body  152  is configured to be received within the channel member  150  and defines protrusions  160  that are received within the openings or recesses  158  of the channel member  150  to secure the cartridge body  152  within the channel member  150 . The cartridge body  152  and the channel member  150  define longitudinal slots  162  and  162   a  respectively to facilitate passage of the vertical strut  130  of the working member  122  such that the lower beam  128  is positioned along an outer surface  150   a  of the channel member  150 . 
     When the tool assembly  114  is actuated by the actuating device  12 , the working member  122  is translated through the tool assembly  114 . As this occurs, the vertical strut  130  of the working member  122  translates through the longitudinal slot  146  of the anvil plate  138  and the longitudinal slots  162  and  162   a  of the cartridge body  152  and channel member  150  to dissect tissue clamped between the anvil plate  138  and the cartridge body  152 . In addition, the upper beam  126  translates through the channel  140  defined between the anvil body  136  and the anvil plate  138  and the lower beam  128  translates along the outer surface  150   a  of the channel member  150  to move the tool assembly  114  to the approximated position and to maintain a maximum tissue gap between the anvil plate  138  and the cartridge body  152  during staple firing. 
     The tool assembly  114  is coupled to the proximal body portion  110  of the stapler reload  100  by a mounting assembly  170 . The mounting assembly  170  is fixedly secured to the proximal end of the tool assembly  114  and pivotally secured to the distal end of proximal body portion  110  such that pivotal movement of mounting assembly  170  about an axis perpendicular to the longitudinal axis of proximal body portion  110  effects articulation of the tool assembly  114 . 
     Mounting assembly  170  includes an upper and a lower mounting portion  172 ,  174 , respectively. Each of the upper and lower mounting portions  172 ,  174  includes a centrally located pivot member  176 . A coupling member  180  interconnects each of the upper and lower mounting portions  172 ,  174  with the distal end of the proximal body portion  110  of the stapler reload  100 . More specifically, each of the coupling members  180  defines an opening  182  and an interlocking proximal portion  184 . Each of the openings  182  is configured to receive a respective one of the pivot members  176  of the upper and lower mounting portions  172 ,  174  to pivotally secure the tool assembly  114  to the proximal body portion  110 . Further, each of the interlocking proximal portions  184  is configured to be received within a correspondingly shaped groove  186  formed in the proximal end of upper and lower housing halves  116   a ,  116   b  to retain mounting assembly  170  and upper and lower housing half-sections  116   a ,  116   b , respectively, in a longitudinally fixed position in relation to each other. 
     In embodiments, the upper and lower mounting portions  172 ,  174  are secured together using pins or rivets  190  and the lower mounting portion  174  is secured within a proximal end of the anvil body  136  using screws  192 . The screws  192  may also extend through openings  194  and  196  in the anvil body  136  and the channel member  150  to pivotally secure the channel member  150  to the anvil body  136 . 
     A pair of blow out plate assemblies  200  are positioned adjacent the distal end of proximal body portion  200  adjacent the distal end of drive assembly  124  to prevent outward buckling and bulging of drive member  118  during articulation and firing of stapling device  10 . In addition, a locking member  202  is supported on a proximal end of the proximal body portion  110  and is movable from a first position in which locking member  202  maintains drive assembly  124  in a ready-to-load position to a second position in which drive assembly  124  is free to move axially. The blow out plate assemblies  200  and the locking member  202  are described in the &#39;924 patent above and will not be described in further detail herein. 
     Referring to  FIGS. 4-6 , the cartridge body  152  defines three longitudinal channels  204  on each side of the longitudinal slot  162  that receive staple legs of the triple leg staples  154  as discussed in further detail below. The three longitudinal channels  204  are separated by a pair of dividing walls  206 . Each of the dividing walls  206  defines a series of pockets  208  positioned to receive a backspan  240  of a triple leg staple  154 . Each of the pockets  208  has a narrow inlet  210  such that the backspan  240  of a triple leg staple  154  is received within a respective pocket  208  in a snap-fit type manner. The narrow inlet may be defined by a resilient retaining feature  208   a , such as a bump or protrusion, formed on a raised sloped wall  209  defining an entrance to the pocket  208 . The pockets  208  define bearing surfaces and the dividing walls  206  define guide surfaces for guiding movement of the triple leg staples  154  as the triple leg staples  154  are ejected from the cartridge body  152  as discussed in further detail below. 
     Referring also to  FIGS. 7-10B , the tri-staples  154  are supported on the cartridge body  152  in a first row  220  and a second row  222 . The first row  220  of staples  154  is supported on the dividing walls  206  ( FIG. 6 ) on the right side of the longitudinal slot  162  such that the staple legs of each of the tri-staples  154  are received within the longitudinal channels  204  ( FIG. 6 ) on the right side of the longitudinal slot  162 . The second row  222  of staples  154  is supported on the dividing walls  206  on the left side of the longitudinal slot  162  such that the staple legs of each of the tri-staples  154  are received within the longitudinal channels  204  on the left side of the longitudinal slot  162 . Each of the staples  154  in the first row  220  is a right hand staple  154   a  ( FIG. 8B ) and includes three staple legs including a right leg  224 , a middle leg  226  and a left leg  228 . In embodiments, the right leg  224  is longer than the middle leg  226  and the middle leg  226  is longer than the left leg  228 . Each of the staples  154  in the second row  222  is a left hand staple  154   b  and includes three staple legs including a left leg  230 , a middle leg  232  and a right leg  234 . In embodiments, the left leg  230  is longer than the middle leg  232  and the middle leg  232  is longer than the right leg  234 . The right hand staples  154   a  and the left hand staples  154   b  are mirror images of each other. As such, only the right hand staples  154   a  will be described in further detail herein. 
     As discussed above, the right hand staples  154   a  ( FIGS. 8B, 9B, 10B ) have three staple legs including a right leg  224 , a middle leg  226  and a left leg  228 . Each of the legs  224 ,  226 , and  228  has a substantially curved V-shape. The right and left legs  224  and  228  are interconnected by a backspan  240  having a U-shaped portion  242  that extends in a distal direction between the right and left legs  224  and  228 . The backspan  240  includes two linear portions  243  ( FIG. 10B ), one on each side of the U-shaped portion  242 . The linear portions  243  of the backspan  240  are received in the pockets  208  of the cartridge body  152  to rotatably support the triple leg staples  154  on the cartridge body  152 . The middle leg  226  includes a hooked portion  244  that is wrapped about a distal end of the U-shaped portion  242  of the backspan  240  such that the middle leg  226  is rotatably supported about the distal end of the U-shaped portion  242 . The right leg  224 , the middle leg  226  and the left leg  228  each includes a tissue piercing distal end  250  that is positioned to engage a respective right, middle and left leg of an adjacent, distal triple leg staple  154  when supported within the cartridge body  152  such that the adjacent, distal triple leg staple guides movement of each triple leg staple  154  as the triple leg staples  154  are ejected from the cartridge body  152 . The distal-most triple leg staple  154   c  ( FIG. 7 ) in each of the first and second rows  220  and  222  of triple leg staples  154  is a dummy staple that is not fired but rather acts as a guide for the proximal adjacent staple  154   d . In alternate embodiments, the dummy staple could be replaced with a projection (not shown) provided on the cartridge body  152  to guide movement of the distal-most triple leg staple  154 . 
     As best shown in  FIG. 9B , the distal ends of the right and left legs  224  and  228  of each triple leg staple  154  are axially aligned whereas the distal and of the middle leg  226  is positioned distally of the distal end of the right and left legs  224  and  228 . The proximal end of the right leg  224  is positioned proximally of the proximal end of the left leg  228 . It is noted that in both the right hand staples  154   a  and the left hand staples  154   b , the longest leg, i.e., the right leg  224  and the left leg  230 , respectively, is positioned furthest from the longitudinal slot  162  and the shortest leg, i.e., the left leg  228  and the right leg  234 , respectively, is positioned closest to the longitudinal slot  162 . This allows for greater tissue compression nearest the tissue cut line and reduced tissue compression away from the tissue cut line. By reducing tissue compression further from the cut line, a reduced amount of blood can flow towards the cutline to minimize tissue necrosis in the tissue adjacent the staple. For a more detailed discussion of the benefits of varying the staple compression between the inner and outer rows of staples, see U.S. Pat. No. 8,925,785 which is incorporated herein in its entirety by reference. 
     Referring to  FIGS. 11-15 , the cartridge assembly  134  ( FIG. 3 ) includes a sled  260  that is positioned distally of the working member  122  and is movably supported within the cartridge body  152  in response to movement of the working member  122  through the cartridge body  152 . The sled  260  includes six firing cams including three right side firing cams  262  and three left side firing cams  264 . Each firing cam  262  and  264  is positioned to be received in one of the three longitudinal channels  204  ( FIG. 6 ) positioned on each side of the longitudinal slot  162  of the cartridge body  152 . The firing cams  262  are positioned to engage the proximal ends of the right, middle and left legs of the right hand staples  154   a  and the firing cams  264  are positioned to engage the proximal ends of the left, right and middle legs of the left hand staples  154   b  to simultaneously eject all three legs of each triple leg staple  154 . As can be seen in  FIG. 14 , the distal ends  262   a - c  of the right side firing cams  262  are axially offset from each other to engage the proximal ends of the legs  224 ,  226  and  228  of the right handed staples  154   a  simultaneously and the distal ends  264   a - c  of the left side firing cams  264  are axially offset from each other to engage the proximal ends of the legs  230 ,  232  and  234  of the left handed staples  154   b  simultaneously. 
     Each of the firing cams  262  and  264  of the sled  260  includes a curved nose  270  that is positioned to engage and rotate a respective leg of a triple leg staple  154  to force the leg into the anvil plate  138  ( FIG. 29A ) until the respective leg is fully formed. Each of the firing cams  262  and  264  also includes a ramp  272  positioned proximally of the curved nose  270  that is positioned to engage the triple leg staples  154  and lift the triple leg staples  154  from the pockets  208  to separate the triple leg staples  154  from the cartridge body  152 . In embodiments, the inner firing cams  262   c ,  264   c  have a height that is greater than the outer firing cams  262   a ,  264   a  and the middle firing cams  262   b ,  264   b , and the middle firing cams  262   b ,  264   b  have a height that is greater than the outer firing cams  262   a ,  264   a . As discussed above, this provides a greater compressive force on tissue closest to the tissue cut line adjacent longitudinal knife slot  162 . 
     Referring to  FIGS. 16 and 17 , the staple deforming recesses  144  of the anvil plate  138  of the anvil assembly  132  has an enlarged concavity  280  having inwardly tapered walls  280   a  and a channel portion  282  that extends proximally from the enlarged concavity  280 . The inwardly tapered walls  280   a  of each recess  144  are configured to receive the distal end  250  of a staple leg of a triple leg staple  154  and direct the distal end  250  ( FIG. 29A ) into the channel portion  282  of the staple deforming recess  144 . The channel portion  282  has a curved bottom wall  282   a  confined by sidewalls  282   b . The curved bottom wall  282   a  is configured to deform the staple leg upwardly into a substantially D-shape. The sidewalls  282   b  of the channel portion  282  are substantially vertical to minimize malformation of the staple leg. 
     Referring to  FIGS. 18 and 19 , the channel member  150  of the cartridge assembly  134  includes a cam surface  300  that is contiguous with the outer surface  150   a  of the channel member  150 . The cam surface  300  is positioned on the proximal end of the channel member  150 . Prior to operation of the actuating device  12  ( FIG. 1 ), the drive assembly  124  is in a retracted position such that the working member  122  is positioned proximally of the sled  260  and proximally of the cam surface  300 . In this position, a distal end of the cartridge assembly  134  is pivoted away from the distal end of the anvil assembly  132  by a biasing member (not shown) such that the tool assembly  114  is in an open position. 
     Referring to  FIGS. 20-28 , when the actuation device  12  ( FIG. 1 ) is operated to advance the drive assembly  124  ( FIG. 20 ), the working member  122  of the drive assembly  124  is advanced in the direction indicated by arrow “A” in  FIG. 20  to a position distal of the cam surface  300  to a position slightly proximal of the sled  260 . As the working member  122  moves past the cam surface  300 , the lower beam  128  engages the cam surface  300  to pivot the cartridge assembly  134  in the direction indicated by arrow “B” in  FIG. 20  to a position in juxtaposed alignment with the anvil assembly  132  to move the tool assembly  114  to the clamped position. 
     In the clamped position of the tool assembly  114 , each of the right side and left side firing cams  262  and  264  of the sled  260  is positioned proximally of a respective leg of the proximal-most triple leg staples  154   d  ( FIG. 25 ) and the linear portions  243  ( FIG. 22 ) of the backspans  240  of the triple leg staples  154  are supported within the pockets  208 . As discussed above, the triple leg staples  154  can be retained in the pockets  208  in a snap-fit manner with resilient retaining features  208   a . As noted above, the distal end  250  ( FIG. 22 ) of each leg of each triple leg staple  154  is positioned to engage a leg of the adjacent distal triple leg staple  154 . 
     Referring to  FIGS. 29A-29C , when the actuating device  12  ( FIG. 1 ) is operated to fire the triple leg staples  154 , the drive assembly  124  is advanced to advance the working member  122  through the tool assembly  114 . As the working member  122  translates through the tool assembly  114 , the upper beam  126  of the working member  122  moves through the channel  140  defined within the anvil assembly  132  and the lower beam  128  of the working member  122  slides along the outer surface  150   a  of the channel member  150  to maintain a maximum tissue gap between the anvil plate  138  and the cartridge body  152  during firing. As this occurs, the working member  122  engages the proximal end of the sled  260  to advance the sled  260  through the cartridge body  152 . 
     As the sled  260  translates through the cartridge body  152 , the firing cams  262  and  264  pass through the longitudinal channels  204  formed on the left and right sides of the longitudinal slot  162  in the direction indicated by arrows “C” in  FIGS. 29A-C  into engagement with each of the triple leg staple legs  154 . As shown in  FIGS. 29A-29C , as each of the firing cams  262  and  264  (only firing cams  262  are shown) engage the right, middle and left legs  224 ,  226 , and  228 , respectively, of the triple leg staples  154 , the curved nose  270  of each firing cam  262  rotates a respective triple leg staple leg  224 ,  226 , and  228  upwardly into a respective staple deforming recess  144 . As this occurs, the linear portions  243  ( FIG. 22 ) of the backspans  240  of the triple leg staples  154  remain supported within the pockets  208  such that the right and left triple leg staple legs  224  and  228  rotate about an axis defined by the linear portions  243  of the backspan  240  and the middle triple leg staple leg  226  rotates about the distal end of the U-shaped portion  242 . As shown, as each of the triple leg staple legs rotates, the distal end  250  of each leg  224 ,  226  and  228  engages and is guided by the adjacent, distal triple leg staple  154 . 
     It is noted that as the working member  122  of the drive assembly  124  translates through the tool assembly  114 , the cutting edge  130   a  formed on a distal side of the vertical strut  130  cuts tissue “T” clamped between the anvil plate  138  and the cartridge body  152 . 
     Referring to  FIGS. 30A-30C , as the sled  260  continues to move through the cartridge body  152  in the direction indicated by arrow “D” in  FIGS. 30A-30B , the firing cams  262  and  264  (only firing cams  262  are shown) continue to rotate the staple legs  224 ,  226  and  228  upwardly into respective staple deforming recesses  144  of the anvil assembly  132  to fully deform the triple leg staple legs  224 ,  226 , and  228  into a substantially D-shape. Once again, it is noted that the linear portions  243  ( FIG. 22 ) of the backspans  240  of the triple leg staples  154  remain supported within the pockets  208  of the cartridge body  152 . 
     Referring to  FIGS. 31A-31C , after the triple leg staple legs  224 ,  226 , and  228  have been fully formed and the sled  260  continues to be advanced by the actuating device  12  in the direction indicated by arrow “E” in  FIGS. 31A-31C , a proximal end of each of the fully deformed triple leg staple legs  224 ,  226 , and  228  is engaged by a ramp  272  of the respective firing cam  262 . As the ramps  272  lift the proximal end of each of the triple leg staple legs  224 ,  226 , and  228  upwardly in the direction indicated by arrow “F” in  FIGS. 31A-31C , the linear portions  243  ( FIG. 22 ) of the backspans  240  of the triple leg staples  154  are disengaged from the pockets  208  to disengage the triple leg staples  154  from the cartridge body  152 . As can be seen in  FIGS. 31A-31C , as the ramps  272  engage the fully deformed triple leg staple legs  224 ,  226 , and  228  to disengage the triple leg staples  154  from the cartridge body  152 , the curved nose  270  of the firing cams  262  engage the adjacent distal triple leg staple  154  to begin to deform the triple leg staple legs  224 ,  226 , and  228 . 
     After the triple leg staples have been deformed and ejected from the cartridge body  152  and applied to tissue “T”, the triple leg staples define three rows of staples legs on each side of the longitudinal knife slot  162 . 
     Referring to  FIG. 33 , it is envisioned that the presently disclosed surgical stapler could be provided with a buttress material  400 . U.S. Publication No. 2014/0048580 discloses methods of attaching a buttress material to a surgical stapler and is incorporated herein in its entirety by reference. 
     Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described embodiments. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims.