Abstract:
A method of manufacturing a surgical instrument for deploying a plurality of surgical fasteners. The method uses the step of building a frame with a proximal end and a distal end, and assembling a handle onto the proximal end of the frame. The method then uses the step of building a support structure adapted to support cartridge containing the plurality of surgical fasteners, and assembling the support structure onto the distal end of the frame. The method also uses the step of building a closure member for supporting at least a portion of the plurality of surgical fasteners for movement from the open position to the closed position. Wherein the step of building the closure member uses the step of molding the closure member from a plastic.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a Continuation In Part of U.S. patent application Ser. No. 11/014,910, filed on Dec. 20, 2004, which claims priority from U.S. Provisional Patent Application Ser. No. 60/532,912 filed Dec. 30, 2003 on which is hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to a surgical stapling and cutting instrument adapted for use in the diagnosis and therapy of pathologies treated by stapled resection. More particularly, the present invention relates to a surgical stapling and cutting instrument having a curvature particularly adapted to fit the anatomy of a human male pelvis.  
       BACKGROUND OF THE INVENTION  
       [0003]     Surgical stapling and cutting instruments are commonly utilized in the diagnosis and treatment of pathologies treated by staple resection. Surgical stapling instruments provide a mechanism to extend the transluminal exploitation of mechanical suturing devices introduced via the anal canal, mouth, stomach and service accesses. Although surgical stapling and cutting instruments are most commonly utilized with rectal pathologies, surgical stapling and cutting instruments may be used in a variety of environments.  
         [0004]     Over time, surgical stapling and cutting instruments have been developed. These instruments generally include a support frame, an anvil attached to the support frame and a cartridge module carrying a plurality of staples or fasteners. The instruments also include a driver within the cartridge module which pushes all of the staples or fasteners out simultaneously into the anvil to form the staples into a generally B-shape or joining multiple part polymer fasteners together, suturing tissue together. In addition, these instruments include approximation mechanisms for moving the cartridge module from a spaced position relative to the anvil to accept tissue there between to a closed position where the tissue is clamped between the anvil and the cartridge module. Finally, the instruments include a firing means for moving the staple driver forward to form the staples against the anvil.  
       SUMMARY OF THE INVENTION  
       [0005]     In accordance with the present invention, there is provided a method of manufacturing a surgical instrument for deploying a plurality of surgical fasteners. The method uses the step of building a frame with a proximal end and a distal end, and assembling a handle onto the proximal end of the frame. The method then uses the step of building a support structure adapted to support cartridge containing the plurality of surgical fasteners, and assembling the support structure onto the distal end of the frame. The method also uses the step of building a closure member for supporting at least a portion of the plurality of surgical fasteners for movement from the open position to the closed position. Wherein the step of building the closure member uses the step of molding the closure member from a plastic. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is a perspective view of the linear surgical stapler in accordance with the present invention.  
         [0007]      FIG. 2  is perspective view of the linear surgical stapler with the cartridge module removed.  
         [0008]      FIG. 3  is a perspective view of the linear surgical stapler with the cartridge housing moved to an intermediate position.  
         [0009]      FIG. 4  is a perspective view of the linear surgical stapler with the cartridge housing moved to a closed position.  
         [0010]      FIG. 5  is a perspective view of the linear surgical stapler with the firing trigger in a firing position.  
         [0011]      FIG. 6  is an exploded view of the cartridge module.  
         [0012]      FIG. 7  is a front perspective view of the cartridge module with the retainer secured thereto.  
         [0013]      FIG. 8  is a front perspective view of the cartridge module with the retainer removed.  
         [0014]      FIG. 9  is a rear perspective view of the cartridge module showing the cartridge housing slot in substantial detail.  
         [0015]      FIGS. 10, 11  and  12  show the assembly of the retainer.  
         [0016]      FIG. 13  is a partial cross-sectional view of the linear surgical stapler in an unactuated orientation.  
         [0017]      FIG. 14  is a exploded view of the pin actuation mechanism.  
         [0018]      FIG. 15  is a partial cross sectional view of the linear surgical stapler with the closure trigger slightly retracted.  
         [0019]      FIG. 16  is a partial cross sectional view of the linear surgical stapler with the closure trigger nearly fully retracted.  
         [0020]      FIG. 17  is a partial cross sectional view of the linear surgical stapler with the closure trigger fully retracted.  
         [0021]      FIG. 18  is a partial cross sectional view of the linear surgical stapler with the firing trigger and closure trigger fully retracted.  
         [0022]      FIG. 19  is partial cross sectional view of the linear surgical stapler after the surgeon depresses the release button.  
         [0023]      FIG. 20  is a partial cross sectional view of the linear surgical stapler upon release of the closure and firing triggers without returning to an intermediate detent position.  
         [0024]      FIG. 21-29  show the insertion of a cartridge module and the removal of the retainer.  
         [0025]      FIGS. 30-38  show the various steps involved in the actuation of the present linear surgical stapler.  
         [0026]      FIGS. 39 and 40  are detailed front views of the cartridge housing. 
     
    
     DETAILED DESCRIPTION  
       [0027]     The detailed embodiments of the present invention are disclosed herein. It should be understood, however, that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limiting, but merely as the basis for teaching one skilled in the art how to make and/or use the invention.  
         [0028]     Referring to  FIG. 1  in combination with FIGS.  2  to  5 , there is shown a surgical stapling and cutting instrument, in particular, a linear surgical stapler  20  which is designed to staple and cut tissue. The linear surgical stapler  20  has a handle  21  at a first proximal end and an end effector  80  at an opposite distal end. The end effector  80  is curved in accordance with a preferred embodiment of the present invention. Right and left hand structural plates (often called “handle plates”)  34 ,  35 , respectively, connect the handle  21  to the end effector  80  of the instrument (the left hand handle plate is not shown in  FIG. 1 ). The handle  21  has a right hand shroud  22  coupled to a left hand shroud (the left hand shroud is not shown in  FIG. 1 ). The handle  21  also has a body portion  23  to grip and maneuver the linear surgical stapler  20  (see FIGS.  2  to  5 ).  
         [0029]     The linear surgical stapler  20  in accordance with the present invention is particularly adapted for insertion into the human male pelvis. In particular, the male pelvis includes portions which are relatively small and, therefore, difficult to access during lower anterior resection (LAR), which requires that the instrument reach within the pelvis in the proximity of the dentate line. The present surgical stapler  20  is specifically shaped and dimensioned for access within the male pelvis during lower anterior resection. In particular, the end effector  80  of the linear surgical stapler  20  is adapted to fit and function within an oval envelope of 3.62 inches by 3.00 inches.  
         [0030]     With this in mind, and in accordance with a preferred embodiment of the present invention, the linear surgical stapler  20  has a distal end with a tissue end effector  80  having a curvature with a diameter of a 7.8 inches or less, and more preferably, four inches or less, in order to fit into a minimum envelope of the male pelvis. More particularly, the end effector  80  has a curvature with a diameter between approximately one inch and approximately four inches, and more preferably between approximately two inches and approximately four inches. In accordance with a more preferred embodiment, the end effector  80  has a curvature with a diameter of approximately 3 inches.  
         [0031]     While the present end effector  80  is disclosed below as being adapted for use in conjunction with a replaceable cartridge module  120  having various components, the concepts underlying the present invention could be applied to a variety of end effector and cartridge module constructions without departing from the spirit of the present invention.  
         [0032]     The end effector  80  is a surgical fastening assembly that includes a cartridge module  120  (see FIGS.  6  to  9 ) and a C-shaped supporting structure  81 . The term C-shaped is used throughout the specification to describe the concave nature of the supporting structure  81  and the cartridge module  120 . The C-shaped construction facilitates enhanced functionality and the use of the term C-shaped in the present specification should be construed to include a variety of concave shapes which would similarly enhance the functionality of surgical stapling and cutting instruments. The distal end  30  of a closure member  28  is disposed to receive the cartridge module  120 . The end effector  80  also includes a safety lockout mechanism  180  (best seen in  FIG. 31 ) for preventing the firing of a previously fired cartridge module  120 . The cartridge module  120  contains a cartridge housing  121  coupled to an anvil  122 . The cartridge module  120  also includes a retaining pin  125 , a knife  126 , a removable retainer  160 , a tissue contacting surface  127  which displays a plurality of staple-containing slots  128  in staggered formation in one or more rows (that is, staple lines) on either side of the knife  126 . Staples (not shown) are fired from the cartridge housing  121  against staple-forming surface  129  of the anvil  122  that faces the tissue-contacting surface  127  of the cartridge housing  121 .  
         [0033]     As will become apparent based upon the following disclosure, the present linear surgical stapler  20  is designed as a multiple firing device with a replaceable cartridge module  120 . However, it should be understood that many of the underlying concepts of the present invention may be equally applied in single firing devices without departing from the spirit of the present invention.  
         [0034]     The supporting structure  81  of the end effector  80  is respectively attached to the right and left handle plates  34 ,  35 , by a shoulder rivet  82  and posts  83  which extend from the supporting structure  81  into receiving holes in the handle plates  34 ,  35 . In accordance with a preferred embodiment of the present invention, the supporting structure  81  is formed via a single piece construction. More specifically, the supporting structure  81  is formed by extrusion, for example, of aluminum, with subsequent machining to create the supporting structure  81  disclosed in accordance with the present invention. By constructing the supporting structure  81  in this manner, multiple parts are not required and the associated cost of manufacture and assembly is substantially reduced. In addition, it is believed the unitary structure of the supporting structure  81  enhances the overall stability of the present linear surgical stapler  20 . In addition, the unitary extruded structure of the supporting structure  81  provides for a reduction in weight, easier sterilization since cobalt irradiation will effectively penetrate the extruded aluminum and less trauma to tissue based upon the smooth outer surface achieved via extrusion.  
         [0035]     The handle  21  of the linear surgical stapler  20  includes a handgrip  24  which the surgeon grasps with the palm of his hand (see FIGS.  2  to  5 ). The handgrip  24  is composed of a right hand shroud handle  25  (see  FIG. 1 ) and a left hand shroud handle (the left hand shroud handle is not shown in  FIG. 1 ). Pivotally extending from the underside of the handle  21  are a closure trigger  26  and a firing trigger  27 . The linear surgical stapler  20  illustrated in  FIG. 1  is shown with the closure and firing triggers  26 ,  27  in their unactuated positions and with a cartridge module  120  inserted and the retainer  160  removed. Consequently, the cartridge housing  121  is spaced from the anvil  122  for the placement of tissue between the cartridge housing  121  and the anvil  122 .  
         [0036]     The handle  21  of the linear surgical stapler  20  contains a tissue retaining pin actuation mechanism  100 . The tissue retaining pin actuation mechanism  100  includes a saddle shaped slide  101  positioned on the top surface of the handle  21 . Manual movement of the slide  101  results in distal movement of the push rod  102 . The push rod  102  is coupled to the retaining pin  125  of the cartridge module  120 . The distal movement or proximal retraction of the push rod  102  results in corresponding movement of the retaining pin  125 . The retaining pin actuation mechanism  100  is also releasably coupled to the closure trigger  26  within the handle  21  such that actuation of the closure trigger  26  will result in automatic distal movement of the retaining pin  125  if it has not already been manually moved to its most proximal position.  
         [0037]     Referring briefly to FIGS.  2  to  5 , there is illustrated what happens when the cartridge module  120  is loaded and the closure and firing triggers  26 ,  27  are sequentially squeezed toward the handgrip  24  to actuate the end effector  80  of the linear surgical stapler  20 . The linear surgical stapler  20  is loaded with the cartridge module  120 , as shown in  FIG. 2 , and the retainer  160  is removed. The linear surgical stapler  20  is now ready to receive tissue as shown in  FIG. 1 .  
         [0038]     When the closure trigger  26  is partially squeezed to rest in its first detent position shown in  FIG. 3 , the cartridge housing  121  moves from its fully opened position to an intermediate position between the open and closed positions as discussed below in greater detail. Simultaneously, the tissue retaining pin actuation mechanism  100  moves the retaining pin  125  forward from the cartridge housing  121  through an opening in the anvil  122 . In this position, tissue which has been placed between the cartridge housing  121  and the anvil  122  can be properly positioned, and the retention of the tissue between the cartridge housing  121  and the anvil  122  is assured. Therefore, when the closure trigger  26  has been actuated to its intermediate position, the cartridge housing  121  and anvil  122  are correspondingly positioned in their tissue retaining positions.  
         [0039]     When the closure trigger  26  is fully squeezed so that it is adjacent the forward end of the handgrip  24 , as illustrated in  FIG. 4 , the tissue contacting surface  127  of the cartridge housing  121  and the staple-forming surface  129  of the anvil  122  are adjacent to each other, and the properly positioned and retained tissue is consequently fully clamped. Additionally, the firing trigger  27  has rotated counterclockwise toward the handgrip  24  to enable the surgeon to grasp the firing trigger  27  for the firing of staples. Accordingly, the firing trigger  27  is now in position for the surgeon to squeeze it to staple and cut the tissue. When the firing trigger  27  has been fully squeezed to fire the staples, as shown in  FIG. 5 , the firing trigger  27  rests in near proximity to the closure trigger  26 .  
         [0040]     Referring now to FIGS.  6  to  9 , a more detailed description of the cartridge module  120  is presented. The present cartridge module  120  provides a cutting and sealing mechanism for utilization within the linear surgical stapler  20  wherein the stapling and cutting functions operate in the same direction during device actuation. Although the present cartridge module  120  is particularly adapted for use in conjunction with linear surgical stapling devices, the concepts of the present cartridge module  120  may be applied to other surgical devices without departing from the spirit of the present invention. In particular, the present cartridge module  120  provides that the knife  126  be utilized in conjunction with a corresponding washer  123  during the cutting process. The present cartridge module  120  ensures that multiple firings of the linear surgical stapler  20  will not compromise cutting performance. This is accomplished by incorporating the anvil  122 , in particular, the cutting washing  123 , with the cartridge module  120 . By combining the washer  123  and knife  126  with the cartridge module  120 , a new washer  123  and knife  126  is provided each time the cartridge module  120  is replaced, resulting in improved cutting performance.  
         [0041]     Enhanced performance is further provided by positioning the anvil  122  and the cartridge housing  121  parallel such that they move relative to each other with the facing surfaces of the anvil  122  and the cartridge housing  121  maintained in a parallel orientation. This provides for an even distribution of pressure across the tissue, preventing squeezing of the tissue in a manner which might bunch the tissue and force portions of the tissue out of the desired spaced defmed between the anvil  122  and the cartridge housing  121 .  
         [0042]     More specifically, the cartridge module  120  includes a cartridge housing  121  that contains a plurality of staples (not shown) positioned in staple-containing slots  128 . Immediately behind the staples is disposed a driver  131  which is disposed to push the staples out of the staple slots  128 . A knife holder  130  is disposed immediately proximal of the driver  131  in the cartridge housing  121 . The knife holder  130  contains a slot  172  and ledge  173  for interaction with a knife retractor hook  45  (see  FIG. 37 ) the function of which will be discussed below in greater detail. The knife holder  130  is attached to a knife  126  that extends distally from the knife holder  130  through a slot  200  in the driver  131  and through a slot  199  in the cartridge housing  121 . Although the knife is disclosed as being within the housing in accordance with a preferred embodiment of the present invention, other configurations may be employed without departing from the spirit of the present invention; for example, it is contemplated that the cartridge module could be constructed without a knife if specific applications so dictate.  
         [0043]     The knife holder  130  has a detent post  138  that extends through the slot  137  in the cartridge housing  121 . The knife holder detent post  138  is disposed to contact detent protrusion  139  of the cartridge slot  137  during the longitudinal travel of the knife  126  and the knife holder  130 . Similarly, the driver  131  has a detent post  140  that is disposed to contact proximal and distal detent protrusions  141 ,  142 , respectively, of the cartridge slot  137 .  
         [0044]     The knife  126  and slots  199 ,  200  are positioned such that there is at least one row of staples on either side of the knife  126 . In accordance with a preferred embodiment of the present invention, two rows of staple slots  128  (and two rows of staples) are provided on each side of the slot  199  of the cartridge housing  121 .  
         [0045]     The cartridge housing  121  contains two generally circular openings  143 ,  144  at either end of the knife slot  199 . The general circular opening  143  at the base of the cartridge housing  121  is shaped and dimensioned for the passage of a guide pin  124  through the cartridge housing  121 . The generally circular hole  144  at the top of the cartridge housing  121  is shaped and dimensioned for the passage of a retaining pin  125  through the cartridge housing  121 . The staple slots  128  are arranged such that the staples laterally extend past the generally circular holes  143 ,  144 .  
         [0046]     In accordance with a preferred embodiment of the present invention, the anvil  122  includes a plastic washer  123  and a metallic staple-forming surface  129 . The anvil  122  is disposed to maintain staple-forming surface  129  in a matching configuration with the staples. The retaining pin  125  is connected to a coupler  133  by a circumferential slot  135  in the retaining pin  125  and a groove  134  in the coupler  133  (best seen in  FIG. 14 ). The coupler  133  is disposed within an arm  145  of the cartridge housing  121  and is held into the arm  145  by an end cap  146 .  
         [0047]     The guide pin  124  and retaining pin  125  include respective slots  147   a,    147   b  (best seen in  FIGS. 8, 9 ,  36 ,  39  and  40 ) into which the ends  126   a,    126   b  of the knife  126  are disposed. The proximal end  148  of the guide pin  124  is connected to the proximal end  149  of the anvil  122 . The distal end  150  of the guide pin  124  extends from the cartridge housing  121  and extends through a slot  151  of the anvil  122 . A cutting washer  123  slips onto the anvil  122  by means of a groove  152  on the anvil  122  that fits under a tongue  153  on the washer  123 . The opposite end  154  of the cutting washer  123  slips under the anvil arm  155  and is pinned to the anvil arm  155  by a pin  156 . In this position, the cutting surface  157  of the washer  123  extends up through a slot  151  of the anvil  122 . The assembly of the cutting washer  123  to the anvil  122  traps the guide pin  124  into the opening formed by the anvil slot  151  and the cutting surface  157 , thereby, operatively connecting the anvil  122  to the cartridge housing  121 . The retainer  160  is attached to the cartridge module  120  as shown in  FIG. 7  to hold the components of the cartridge module  120  in a desired orientation until insertion into the end effector  80 .  
         [0048]     Turning to FIGS.  6  to  12  in combination with FIGS.  25  to  29 , the retainer  160  will be described in more detail. The retainer  160  has a groove  161  that is disposed around a protrusion  159  of the cartridge housing  121 . The retainer  160  contains a resilient inner spring arm  162  that is disposed for reciprocating movement within the retainer  160 . The retainer  160  includes containment slots  163  which extend partially around the guide pin  124 . The spring arm  162  includes containment slots  164  which extend partially around the guide pin  124 , but are configured to face in an opposing direction to the containment slots  163 . The retainer  160  is positioned onto the cartridge module  120  such that the containment slots  163 ,  164  surround the guide pin  124  and trap the retainer  160  onto the cartridge module  120 . The spring arm  162  includes a disengagement tab  165  which extends down from the retainer  160  below the anvil arm  155 . As such, the retainer  160  is not easily removed from the cartridge module  120  until the cartridge module  120  is properly seated within the end effector  80 . Upon proper seating of the cartridge module  120  within the end effector  80 , the disengagement tab  165  engages the end effector  80  for release of the retainer  160 .  
         [0049]     Referring once again to  FIG. 1  in combination with  FIG. 2  and  FIG. 13 , a more detailed description of the components of the linear surgical stapler  20  is provided. The linear surgical stapler  20  includes an elongated closure member  28 , with a generally U shaped cross section, extending from the handle  21  into the surgical fastening assembly of the end effector  80 . In accordance with a preferred embodiment of the present invention, the closure member  28  is a molded plastic member shaped for movement and functionality in accordance with the present invention. By manufacturing the closure member  28  from plastic, manufacturing costs are reduced and the weight of the linear surgical stapler  20  is also reduced. In addition, the linear surgical stapler  20  is easier to sterilize with cobalt irradiation as plastic is easier to penetrate than stainless steel. Suitable types of plastic include the class of plastics called thermoplastics which include, but are not limited to, polyamide, polyphenylene sulfide, polyethylene terephthalate, polyacetal, polyester, polysulfone, polyethersulfone, polyetherimide, liquid crystal polymers, acrylonitrile butadiene styrene (ABS), polycarbonates, nylon, polyurethane, polyphthalamide, polyether ether ketone, that may or may not be molded with additives such as glass, aramid or carbon fibers or beads to increase strength.  
         [0050]     Molded components can be produced in very controlled shapes with tight tolerances. This would produce the curved shape and intricate features for member  28 . In addition, there is no longer a need to attach multiple plates together. The single piece mold eliminates the need for fasteners such as rivets to hold the closure subsystem together. The other holes for the lockout pin and for the guide rivets can now be precisely aligned as they are molded in the same tool at one time. In addition, plastic weighs far less than stainless steel so the overall weight of the device decreases. In terms of sterilization, a plastic component is much easier to penetrate for cobalt irradiation than several steel laminated plates. Lastly, the use of a one-piece molded closure member allows for the elimination of fasteners, stainless steel closure plates, plastic spacers, making assembly much easier.  
         [0051]     The distal portion of the closure member  28  passes through the walls  84  of the supporting structure  81 . The distal end is disposed to receive and retain the cartridge housing  121  of the cartridge module  120 . The central portion of the closure member  28  is positioned between the right and left handle plates  34 ,  35 , respectively. Right and left hand closure links  36 , 37 , respectively, are pivotally attached at the right and left proximal ends of the closure member  28  by a first integral closure link pin  38 . At the opposite end of the closure links  36 ,  37 , the closure links  36 ,  37  are pivotally attached to a second integral closure link pin  39 . The second integral closure link pin  39  connects the closure links  36 ,  37  to a slotted closure arm link  40 . The slotted closure arm link  40  is pivotally mounted to the handle plates  34 ,  35  of the linear surgical stapler  20  at a closure trigger pivot pin  41 . The closure trigger  26  descends from the slotted closure arm link  40  for pivotal rotation about the closure trigger pivot pin  41  toward and away from the handgrip  24 . A closure spring  42  housed within the handgrip  24  of the handle  21  is secured to the slotted closure arm link  40  to provide a desired resistance when the surgeon squeezes the closure trigger  26  toward the handle grip  24 , and to bias the closure trigger  26  toward the open position.  
         [0052]     Referring to  FIGS. 13 and 14 , the components of the retaining pin actuation mechanism  100  will now be described. The handle  21  contains a saddle shaped slide  101  mounted on top of the handle  21  for linear motion. The slide  101  is connected to a post  103  that extends outward from a push rod driver  104  through slots  105  (see  FIG. 2 ) in the handle  21 . The push rod driver  104  is restrained for longitudinal movement along the long axis of the linear surgical stapler  20  by slots  105 . The push rod driver  104  is connected to the push rod  102  by a circumferential groove  107  on the push rod  102  that snaps into a slot  108  of the push rod driver  104 . The distal end of the push rod  102  contains a circumferential groove  109  that interconnects with a groove  132  in the proximal end of the coupler  133  of the cartridge module  120  (best seen in  FIG. 22 ). The distal end of the coupler  133  contains a groove  134  for interconnecting with a circumferential slot  135  on the retaining pin  125 .  
         [0053]     The closure member  28  contains posts  29  which extend laterally on both sides of the closure member  28  inside the handle  21 . These posts  29  slidably connect to an L-shaped slot  110  of a yoke  111 . The yoke  111  is pivotally mounted to the handle  21  by a pivot pin  112  on the yoke  111 . The yoke  111  contains cam pins  113  positioned to push camming surfaces  114  on the push rod driver  104 .  
         [0054]     Referring to  FIG. 13  and  FIG. 37 , the components of the firing transmission assembly will now be described. The firing transmission assembly has an elongated firing bar  43  extending from the handle  21  into the surgical fastening assembly of the end effector  80 . The firing bar  43  is positioned within the U shaped cross section of the closure member  28 . The distal end of the firing bar  43  extends into the cartridge housing  121  and is positioned just proximally of the knife holder  130  and driver  131 . The distal end of the firing bar  43  is attached to a knife retractor  44  that has a knife retraction hook  45 .  
         [0055]     The firing bar  43  has a rectangular receiving slot  46  in that portion of the firing bar  43  that is housed within the handle  21  (see  FIG. 13 ). The first integral closure link pin  38  extends through the receiving slot  46 . The firing bar  43  also has a proximal end section  47 . The underside of the proximal end section  47  of the firing bar  43  has a sliding surface  48 . The proximal end section  47  also has a terminal side engagement surface  49  extending from the sliding surface  48 . The firing trigger  27  is pivotally mounted to the handle plates  34 ,  35  by a firing trigger pivot pin  50  spaced from the closure trigger pivot pin  41  so that each of the pivot pins pivot about mutually independent axes. The firing trigger  27  includes an arcuate firing trigger link  51  extending from the firing trigger  27  at the firing trigger pivot pin  50  to an apex  52  which rests on the sliding surface  48  of the proximal end section  47  of the firing bar  43 . Within the handle  21 , the firing trigger  27  is attached to first and second firing trigger spring arms  53 ,  54 , respectively. The firing trigger spring arms  53 ,  54  support a torsion spring (not shown) on the right half of the firing trigger  27 . Finally, a firing bar return spring  55  is secured to the underside of the firing bar  43  at that portion of the firing bar  43  within the handle  21  to bias the firing bar  43  toward its unactuated position.  
         [0056]     When the closure trigger  26  is squeezed toward the handgrip  24 , the slotted closure arm link  40  and the closure links  36  and  37 , move distally within the receiving slot  46  of the firing bar  43 . This distal movement causes the closure member  28  to correspondingly move distally. Likewise, the firing bar  43  concurrently moves distally with the closure member  28  because the first integral closure link pin  38 , to which the closure links  36 ,  37  are attached, extends through the receiving slot  46  in the firing bar  43 .  
         [0057]     The mechanism which defines an intermediate closure detent position and the release of the closure trigger  26  from an actuated position to its original unactuated position will now be described in connection with  FIG. 1  in combination with  FIGS. 13-20 . The top side of the slotted closure arm link  40  has a clamp sliding surface  56  that displays an intermediate detent  57  and a closure detent  58 . A release pall  59  slides on the clamp sliding surface  56  and may engage the intermediate and closure detents  57 ,  58 . The release pall  59  has a laterally extending pall lug  60  (best seen in  FIG. 1 ) at its distal end. The release pall  59  is located within the handle  21 , and it is integrally attached to a release button  61  situated exteriorly of the handle  21 . The release button  61  has a thumb rest  62 , and the release button  61  is pivotally attached to the handle  21  by a release trunnion  63 . The release button  61  is biased outwardly from the handle  21  and, therefore, the release pall  59  is biased downwardly toward the clamp sliding surface  56  by a release spring  64  which is mounted to the handle  21  by a spring retention pin  65  and mounted to the release button  61  by a button spring post  66 . The slotted closure arm link  40  has an arcuate recess  67  located between the intermediate and closure detents  57 ,  58 . Sitting within this arcuate recess  67  for rotational movement are a left hand toggle  68  integrally connected to a right hand toggle (the right hand toggle is not shown). Each toggle  68  has a toggle arm  69  that is engageable with the pall lug  60 . The pall lug  60  has a concave proximal surface  70  to provide clearance between the toggle arm  69  and the pall lug  60 .  
         [0058]     Referring to  FIG. 31  (cut away view into cartridge and supporting structure), the components of the fired device lockout mechanism  180  will now be described.  
         [0059]     As will be appreciated based upon the following disclosure, once the device has been fired the lockout mechanism  180  prevents movement of the cartridge housing  121  to its second closed position but permitting relative reapproximation movement of the cartridge housing  121  and anvil  122 , whereby reapproximation provides an indicator that the instrument is not malfunctioning. Permitted reapproximation will constitute approximately ¼ to approximately ⅔ of the total distance between the cartridge housing  121  and the anvil  122  when in the first spaced apart position, and more preferably, ¼, ⅓, or ½ of the total distance between the cartridge housing and the anvil when in the first spaced apart position.  
         [0060]     The lockout mechanism  180  contains a lockout lever  181  that is pivotally mounted to the distal end  30  of the closure member  28  by a pin  182 . The lockout lever  181  is spring biased down toward the base of supporting structure  81  by a spring (not shown). The lockout lever  181  contains a proximal and distal end  184 ,  185 , respectively. The proximal end  184  has a cam surface  186  and locking groove  187 . The supporting structure  81  of the end effector  80  contains a ledge  85  that is disposed to interact with locking groove  187  when the lockout mechanism  180  is engaged. The supporting structure  81  contains abase surface  86  between walls  84 . The base surface  86  is disposed to interact with cam surface  186  when the lockout lever  181  is not engaged.  
         [0061]     The operation of loading the cartridge module  120 , the closure mechanism, the retaining pin mechanism, the firing transmission assembly, the intermediate and closure detents  57 ,  58 , the release mechanism, and the lockout mechanism  180  will now be described. Referring to FIGS.  7  to  12  and FIGS.  21  to  28  the loading of the cartridge module  120  into the tissue end effector  80  is described. The cartridge module  120  is shaped and dimensioned for selective insertion and removal from the tissue end effector  80  of the linear surgical stapler  20 .  
         [0062]     Prior to insertion of the cartridge module  120  into the end effector  80  of the linear surgical stapler  20 , as seen in  FIG. 7 , the retainer  160  can not easily be removed from the cartridge module  120  as the groove  161  is disposed around the protrusion  159  at the top end of the retainer  160  preventing disconnection. Further, the containment slots  163 ,  164  of the retainer are disposed around the guide pin  124  at the bottom of the retainer  160  preventing disconnection as shown in  FIG. 25 . The attached retainer  160  provides support to the structure of the cartridge module  120  and an extended surface area for gripping, both features making loading easier. The retainer  160  also prevents staples from dislodging from the cartridge housing  121  during casual handling and prevents the knife  126  from accidental exposure during casual handling.  
         [0063]     Knife  126  movement and staple movement are further resisted prior to loading and during loading by a series of detents. Referring to  FIG. 9 , detent post  138  on the knife holder  130  is prevented from proximal and distal movement by the detent protrusion  139  on the cartridge housing slot  137 . The driver  131  is prevented from distal movement due to casual handling and during loading of the cartridge module  120  into the linear surgical stapler  20  by the interaction of the detent post  140  and the detent protrusion  141  on the cartridge housing slot  137 .  
         [0064]     The cartridge module  120  is loaded into the tissue effector  80  such that the cartridge housing  121  slips into the distal end  30  of the closure member  28  as seen in FIGS.  21  to  24 .  
         [0065]     Walls  31   a  and  31   b  on the closure member  28  slip into slots  170   a,    170   b  of the cartridge housing  121  during loading. Simultaneously, tabs  174  (See  FIG. 8 ) slip into groove  88  of the C-shaped supporting structure  81 . Loading of the cartridge module  120  is completed when the detents  171  snap onto the detent groove  32  of the closure member distal end  30 , as shown in FIGS.  21  to  24 .  
         [0066]     In the position shown in  FIG. 24 , the cartridge module  120  is fully loaded and the proximal groove  132  of the coupler  133  has engaged the distal circumferential groove  109  of the push rod  102  such that the retaining pin  125  in the cartridge module  120  has been connected to the retaining pin advancement mechanism  100 . The slot  172  of knife holder  131  engages the knife retraction hook  45  during loading such that the hook  45  has engaged the retraction ledge  173  on the knife holder  130  at the completion of the cartridge module  120  loading.  
         [0067]     At the completion of the cartridge module  120  loading a post  188  positioned on driver  131  contacts the distal end  185  of the lockout lever  181  (see  FIG. 31 ). This contact pivots the lockout lever  181  about the lockout lever pin  182  to a position such that the camming surface  186  is horizontally aligned with the base surface  86  of the U shaped supporting structure  81 .  
         [0068]     The retainer  160  can now be removed from the end effector  80 . Specifically, completion of loading the cartridge module  120  causes the disengagement tab  165  to contact the supporting structure  81  (See  FIG. 23 ), resulting in an upward movement of the spring arm  162  when the cartridge module  120  is fully loaded as in  FIG. 24 . This upward movement displaces containment slots  164  upward such that the guide pin  124  is no longer contained (see  FIGS. 25 and 26 ). Referring now to FIGS.  27  to  29 , a removal force applied to the thumb pad  166  results in the retainer  160  pivoting outward about protrusion  159  until the groove  161  is able to slip off protrusion  159 . Removal of the retainer  160  allows for the loaded linear surgical stapler  20  to be utilized.  
         [0069]     In  FIG. 15 , the closure trigger  26  has been partially squeezed from its open, unactuated position illustrated in  FIGS. 1 and 13 . When the closure trigger  26  is partially squeezed, it pivots about the closure trigger pivot pin  41  in a counterclockwise direction toward the handgrip  24 . As it pivots, the slotted closure arm link  40  and closure plate closure links  36 ,  37  move forwardly, consequently moving the closure member  28  and firing bar  43  distally. As the slotted closure arm link  40  moves forwardly, the pall lug  60  of the release pall  59  slides on the clamp sliding surface  56 . The pall lug  60  engages the distal ends of the toggle arms  69  of the toggles  68 , and consequently pivots the toggles  68  in a clockwise direction. As the slotted arm closure link  40  continues to move forwardly in response to the pivotal movement of the closure trigger  26  toward the handgrip  24 , the pall lug  60  of the release pall  59  will eventually lodge into the intermediate detent  57 . Once positioned in the intermediate detent  57 , the closure spring  42  is incapable of returning the closure trigger  26  to its original, unactuated position. The closure trigger  26  is now in its intermediate, partially closed position, to properly position and retain tissue between the cartridge housing  121  and anvil  122 , as shown in  FIG. 15 . In addition, as the closure member  28  and firing bar  43  move distally, the apex  52  of the arcuate firing trigger link  51  slides on the sliding surface  48  of the proximal end section  47  of the firing bar  43 .  
         [0070]     During the closing stroke from the open to the intermediate position the retaining pin mechanism  100  is activated. Forward movement of the closure member  28  moves the integral posts  29  distally. The posts  29  contact the L-shaped slot  110  of the yoke  111 . Hence, distal movement of the posts  29  cam the L-shaped slot  110  causing the yoke to pivot around pins  112 . The rotation brings bearing posts  113  on the yoke  111  into contact with camming surfaces  114  on the push rod driver  104 . Further rotational movement of the yoke  111  causes bearing posts  113  to move the push rod driver  104  distally through camming contact on surfaces  114 . The push rod driver  104  contacts the push rod  102 , moving the push rod  102  distally. The push rod  102 , in turn, moves the coupler  133  and retaining pin  125  distally. Completion of the closing stroke to the intermediate detent  57  position results in the retaining pin  125  moving distally through the hole  144  of the cartridge housing  121 , through the hole  159  running through the washer  123  and anvil  122  and into the hole (not shown) in the supporting structure  81 . Tissue, which was disposed between the contact surface  127  of the cartridge housing  121  and the anvil  122 , is now trapped between retaining pin  125  and the guide pin  124 .  
         [0071]     This same result can be obtained prior to closing by manual distal movement of saddle slide  101 . Slide movement will result in forward movement of the push rod  102 , coupler  133  and retaining pin  125  until the retaining pin  125  is fully disposed through the anvil  122 , washer  123  and hole  89  in the supporting structure  81 . Activation of the closing stroke after the retaining pin  125  has been manually moved forward would still result in the rotation of the yoke  111  as described above but without any additional movement of the retaining pin actuation mechanism  100 .  
         [0072]     The closing stroke from the open to the intermediate detent  57  position moves the lockout lever  181  distally as it is attached to closure member  28  by the pin  182  as shown in  FIG. 31  (open) and  FIG. 32  (intermediate position). Distal movement of the lockout lever  181  causes the camming surface  186  to contact the lockout ledge  85  of the support  81 , resulting in the lockout lever  181  rotating clockwise and coming to slidable contact with base surface  86  of supporting structure  81 . In this position, the distal end  185  of the lockout lever  181  has rotated away from post  188  on driver  131 .  
         [0073]     Referring now specifically to  FIG. 16 , when the closure trigger  26  is squeezed toward the handgrip  24  from the intermediate detent  57  position, the toggle arms  69  of the toggle  68  disengage from the pall lug  60 . Consequently, as the toggle  68  continues to rotate in a clockwise direction, the release pall lug  60  rides up the toggle arms  69  and with continued motion of the closure trigger  26  falls into the closure detent  58 . As the release pall  59  rides up the toggle arm  69  it rotates the release button  61  clockwise around pivot  63 . As the release pall  60  falls into closure detent  58 , it makes an audible clicking sound alerting the surgeon that closure position has been reached.  
         [0074]     In addition, as the firing bar  43  continues to move forwardly, the apex  52  of the arcuate firing trigger link  51  comes into contact with the side engagement surface  49  of the proximal end section  47  of the firing bar  43 . Consequently, the firing trigger  27  is moving into a position where it can continue to move the firing bar  43  distally to fire staples after the tissue has been fully clamped. When the apex  52  of the arcuate firing trigger link  51  moves into engagement with the engagement surface  49  of the proximal end section  47 , the firing trigger  27  begins to pivotally rotate in a counterclockwise direction toward the handgrip  24  in response to the action of a torsion spring on the right hand side of the firing trigger  27  (torsion spring not shown). The firing trigger  27  pivots independently of the pivotal movement of the closure trigger  26 , but its pivotal rotation is blocked until the firing bar  43  has moved distally to enable engagement of the firing trigger link  51  with the terminal engagement surface of the firing bar  43 .  
         [0075]     Turning specifically to  FIG. 17 , when the closure trigger  47  has been fully squeezed and it is adjacent the handgrip  24 , the pall lug  60  at the distal end of the release pall lodge  59  into the closure detent  58 . In the closure detent  58  position, the tissue has been fully clamped between the cartridge housing  121  and anvil  122 , and the closure spring  42  is incapable of returning the closure trigger  26  to its original position. Therefore, the closure trigger  26  is retained in the position shown in  FIG. 4 .  
         [0076]     Concurrently with the counterclockwise motion of the closure trigger  26 , the firing trigger  27  continues to rotate counterclockwise by the action of the torsion firing bar return spring  55  until the firing trigger  27  is in a relatively vertical orientation with respect to the handle  21  of the linear surgical stapler  20 . In the fully clamped position, the apex  52  of the arcuate firing trigger link  51  has fully engaged the engagement surface of the proximal end section  47  of the firing bar  43  and, therefore, the firing trigger  27  is in a position to further move the firing bar  43  distally to fire staples into the tissue.  
         [0077]     In the fully closed position the staple pockets  128  of the cartridge housing  121  are aligned with the staple-forming surface  129  of the anvil  122  as shown in  FIG. 33 . The retaining pin  125  has aligned the top of the anvil  122  and the cartridge housing  121  and the guide pin  124  has aligned the bottom of the cartridge housing  121  with the bottom of the anvil  122 .  
         [0078]     As illustrated in  FIG. 18  and  FIG. 34 , the firing trigger  27  can be squeezed to pivotally rotate it toward the handgrip  24  until it is positioned adjacent the closure trigger  26 . During the pivotal rotation of the firing trigger  27 , the firing bar  43  moves distally, contacts the knife holder  130 . The resulting distal movement of the knife holder  130  results in contact with the knife  126  and driver  131 . Distal movement of the driver  131  results in the staples (not shown) to be distally advanced into the staple forming surfaces  129  of the anvil  122  resulting in staple formation of a generally B shape. The knife  126  distally advances in slots  147  of the guide pin  124  and the retaining pin  125  in conjunction with staple formation. These slots  147  guide the knife  126  onto the cutting surface  157  of cutting washer  123  resulting in the transection of any tissue caught between.  
         [0079]     Release of manual pressure to the firing trigger  27  results in the firing bar return spring  55  to retract the firing bar  43  and returns the firing trigger  27  to the position shown in  FIG. 17 . This movement results in the retraction hook  45  retracting the retraction ledge  173  on the knifeholder  130  and knife  126 . The resulting proximal movement retracts the knife  126  into the cartridge housing  121  as shown in  FIG. 35 . Detent post  138  on the knife holder  130  retracts into engagement with the detent  139  on the cartridge housing  121  to hold the knife holder  130  and knife  126  in this retracted position. The driver  131  is retained in its distal most (fired) position by engagement of the detent post  140  on the driver  131  engaging detent  142  of the cartridge slot  137 .  
         [0080]     Should there be an interference on the knife  126 , as from the user cutting into another surgical instrument by mistake, such that the force from the firing bar return spring  55  is insufficient to retract the firing bar  43  and thus retract the knife  126  into the cartridge housing  121 , the user can manually retract the cutting system by pulling clockwise on the firing trigger  27 . The manual clockwise movement causes the arcuate firing trigger link  51  to rotate clockwise until it strikes a firing bar retraction tab  71  on the proximal end  47  of the firing bar  43 . The contact between the clockwise moving arcuate firing trigger link  51  and the firing bar retraction tab  71  cause the firing bar  43  to retract proximally and return to the position shown in  FIG. 17 . This in turn causes the retraction hook  45  to retract the retraction ledge  173  on the knife holder  130  and knife  126 . Thus, this safety feature allows for the user to retract the cutting mechanism to a safe position and return the firing system to a position that would allow the linear surgical stapler  20  to be opened, as will now be described.  
         [0081]     Referring to  FIG. 19 , when the surgeon depresses the release button  61 , the release pall  59  pivots about a release trunnion  63  in a clockwise direction to dislodge the pall lug  60  from the closure detent  58  position. As it is dislodged, the pall lug  60  rides on the toggle arms  69  to bypass the intermediate detent position  57  on clamp link  40 . In this manner, the closure and firing triggers  26 ,  27  can return to their original, unactuated positions in response to the bias created from the closure spring  42  and firing bar return spring  55 . When the pall lug  60  rides on the toggle arms of the toggles  68 , the toggle arms  69  rotate counterclockwise as the closure and firing triggers  26 ,  27  rotate in a clockwise direction to return to their original unactuated positions. Therefore, the surgeon can release the closure and firing triggers  26 ,  27  so that they can return to the positions illustrated in  FIG. 20  without unnecessarily returning to the intermediate detent  57  position.  
         [0082]     The release of the linear surgical stapler  20  to the open position shown in  FIG. 20  causes the closure member  28  and the attached lockout lever  181  to retract to the full open position as shown in  FIG. 36 . In this position the post  188  on the driver  131  is no longer disposed to hold down the lockout lever distal end  185 . The driver  131 , as described above, has been detented into place in the forward position by post  140  and the cartridge detent  142 . Hence, when the lockout lever  181 , whose proximal end  184  slides along support arm surface  86 , is fully retracted it is now free to rotate counter-clockwise and drop lockout groove  187  below ledge  85  on the C-shaped supporting structure  81 . The lockout lever  181  will remain in this position when the cartridge module  120  is removed as shown in  FIG. 37 .  
         [0083]     Any future attempt to close the linear surgical stapler  20  which has been fired will result in the lockout groove  187  hooking into the ledge  85  as shown in  FIG. 38 , supplying feedback to the user of a previously fired device. This same feature will engage if the retainer  160  has been removed prior to loading and the cartridge module  120  has been misloaded without the cartridge module  120  being in the right position. In this case the driver post  188  would not be in the right position to move lockout lever  181  into the position to be cammed up onto surface  86  as described above. Similarly, a cartridge module  120  which has already been fired would also not release the lockout mechanism  180 . It is important to note that there is closure stroke travel allowed in the lockout mechanism  180  prior to engagement of the lockout groove  187  hooking into the ledge  85 . This travel indicates to the user that the device is not jammed due to some malfunction as might be the reaction if the lockout mechanism  180  had no travel. Hence, the user knows that the device is not jammed but incorrectly loaded when the lockout mechanism engages.  
         [0084]     After release of the device back to the open position shown in  FIGS. 1 and 2 , the retaining pin mechanism  100  must be manually retracted by pulling proximally on saddle  101 . The retraction causes the retaining pin  125  to retract back into the cartridge housing  121 . At the completion of the manual retraction the fired cartridge module  120  can be unloaded and replaced with a new cartridge module  120 .  
         [0085]     The above described device is not only applicable to curved staplers. The invention has equal applicability to non-curved stapler such as those described in U.S. Pat. Nos. 5,605,272 issued to Witt et al. on Feb. 25, 1997, U.S. Pat. No. 5,275,322 issued to Brinkerhoffet al., U.S. Pat. Nos. 5,706,998 issued to 5,706,998, all of which is hereby incorporated herein by reference.  
         [0086]     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. For example, as would be apparent to those skilled in the art, the disclosures herein have equal application in robotic-assisted surgery. In addition, it should be understood that every structure described above has a function and such structure can be referred to as a means for performing that function. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.