Patent Publication Number: US-6988649-B2

Title: Surgical stapling instrument having a spent cartridge lockout

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   The present application is related to four co-pending and commonly-owned applications filed on even date herewith, the disclosure of each is hereby incorporated by reference in their entirety, these four applications being respectively entitled:
     (1) “SURGICAL STAPLING INSTRUMENT HAVING A FIRING LOCKOUT FOR AN UNCLOSED ANVIL” to Frederick E. Shelton IV, Mike Setser, and Bruce Weisenburgh;   (2) “SURGICAL STAPLING INSTRUMENT HAVING SEPARATE DISTINCT CLOSING &amp; FIRING SYSTEMS” to Frederick E. Shelton, Mike Setser, and Brian J. Hemmelgam;   (3) “SURGICAL STAPLER INSTRUMENT HAVING A SINGLE LOCKOUT MECHANISM FOR PREVENTION OF FIRING” to Frederick E. Shelton IV, Mike Setser, Bruce Weisenburgh; and   (4) “SURGICAL STAPLING INSTRUMENT INCORPORATING AN E-BEAM FIRING MECHANISM” to Frederick E. Shelton IV, Mike Setser, and Bruce Weisenburgh.   

   FIELD OF THE INVENTION 
   The present invention relates in general to surgical stapler instruments that are capable of applying lines of staples to tissue while cutting the tissue between those staple lines and, more particularly, to improvements relating to stapler instruments and improvements in processes for forming various components of such stapler instruments. 
   BACKGROUND OF THE INVENTION 
   Surgical staplers have been used in the prior art to simultaneously make a longitudinal incision in tissue and apply lines of staples on opposing sides of the incision. Such instruments commonly include a pair of cooperating jaw members that, if the instrument is intended for endoscopic or laparoscopic applications, are capable of passing through a cannula passageway. One of the jaw members receives a staple cartridge having at least two laterally spaced rows of staples. The other jaw member defines an anvil having staple-forming pockets aligned with the rows of staples in the cartridge. The instrument includes a plurality of reciprocating wedges which, when driven distally, pass through openings in the staple cartridge and engage drivers supporting the staples to effect the firing of the staples toward the anvil. 
   An example of a surgical stapler suitable for endoscopic applications is described in U.S. Pat. No. 5,465,895, which advantageously provides distinct closing and firing actions. Thereby, a clinician is able to close the jaw members upon tissue to position the tissue prior to firing. Once the clinician has determined that the jaw members are properly gripping tissue, the clinician can then fire the surgical stapler, thereby severing and stapling the tissue. The simultaneous severing and stapling avoids complications that may arise when performing such actions sequentially with different surgical tools that respectively only sever or staple. 
   It is often advantageous to build an end effector for the surgical stapler that is reusable. For instance, one patient may need a series of severing and stapling operations. Replacing an entire end effector for each operation tends to be economically inefficient. This is especially true if the end effector is built to be strong and reliable over repeated operations. To that end, staple cartridges are fitted into the end effector prior to each operation of the surgical stapler. Thus, a much smaller amount of the surgical stapler is discarded after each use. 
   While the staple cartridge provides numerous advantages, it is desirable to prevent inadvertent firing of the surgical stapler when a spent staple cartridge is installed. Otherwise, the severing of tissue may occur without the staples to minimize bleeding. 
   It is particularly desirable that preventing such inadvertent firing be accomplished in a reliable way that is not subject to an intervening malfunction. Moreover, for ease of manufacturing and assembly, it is further desirable that the lockout features be accomplished with a minimum number of components. 
   Consequently, a significant need exists for an improved surgical stapling and severing instrument that prevents inadvertent firing (i.e., severing and stapling) when a staple cartridge is not installed or is spent, having been previously fired. 
   BRIEF SUMMARY OF THE INVENTION 
   The invention overcomes the above-noted and other deficiencies of the prior art by providing a lockout mechanism that prevents firing a surgical stapling and severing instrument when a staple cartridge is already spent. In particular, the lock mechanism prevents distal movement of a firing bar, and thus severing of tissue, in instances where simultaneous stapling would not occur. 
   In one aspect of the invention, a surgical instrument includes a handle portion operable to produce a firing motion that actuates an implement portion. This implement portion has an elongate channel that receives a staple cartridge with a firing drive slot defined therebetween. A firing mechanism engages the elongate channel along its longitudinal length and includes an engaging device that traverses the firing drive slot for distally moving a wedge sled in the staple cartridge. A lockout mechanism is advantageously positioned to be moved out of the firing drive slot by the presence of the wedge sled in its unfired, proximal position, and thus allowing the firing bar to fire. When the wedge sled is moved to its distal position (i.e., spent cartridge), the lockout mechanism resiliently moves downwardly from the staple cartridge into the firing drive slot. The proximal and distal sides of the lockout mechanism present in the firing drive slot are shaped to allow the engaging device of the firing bar to return to its proximal, initial position but to thereafter impede distal movement until an unfired staple cartridge is installed. 
   These and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the present invention. 
       FIG. 1  depicts a partially cut-away side elevation view of a surgical stapling and severing instrument in an open position. 
       FIG. 2  depicts a cross-sectional side elevation detail view along the line  2 — 2  of  FIG. 1  of an end effector of the surgical stapling and severing instrument. 
       FIG. 3  depicts an enlarged side elevation view of the firing bar of the surgical stapling and severing instrument of  FIG. 2 . 
       FIG. 4  depicts an enlarged front view of the firing bar of the surgical stapling and severing instrument of  FIG. 2 . 
       FIG. 5  depicts a cross-sectional side elevation detail view of an alternative end effector for the surgical stapling and severing instrument of  FIG. 1 , incorporating a firing bar that lacks a middle pin for preventing pinching of the end effector. 
       FIG. 6  depicts a side elevational view of a handle portion of a proximal end of the surgical stapling and severing instrument of  FIG. 1  with a left side removed to expose interior parts in an unclamped, unfired (“start”) position. 
       FIG. 7  depicts a perspective, exploded view of the handle portion of the proximal end of the surgical stapling and severing instrument of  FIG. 1 . 
       FIG. 8  depicts a side elevational view of the handle portion of the proximal end of the surgical stapling and severing instrument of  FIG. 1  with the left side removed to expose interior parts in the closed (“clamped”) position. 
       FIG. 9  depicts a side elevational view of the handle portion of proximal end of surgical stapling and severing instrument of  FIG. 1  with the left side removed to expose interior parts in the stapled and severed (“fired”) position. 
       FIG. 10  depicts an isometric view of the end effector at the distal end of the surgical stapling and severing instrument of  FIG. 1  with the anvil in the up or open position exposing the staple cartridge and cutting edge of the firing bar. 
       FIG. 11  depicts an isometric, exploded view of the implement portion of the surgical stapling and severing instrument of  FIG. 1 . 
       FIG. 12  depicts an isometric view of the end effector at the distal end of the surgical stapling and severing instrument of  FIG. 1  with the anvil in the up or open position with the cartridge largely removed exposing a single staple driver and a double staple driver as exemplary and the wedge sled in its start position against a middle pin of the firing bar. 
       FIG. 13  depicts an isometric view of the distal end of the surgical stapling and severing instrument of  FIG. 1  with the anvil in the up or open position with the staple cartridge completely removed and a portion of an elongate channel removed to expose a lowermost pin of the firing bar. 
       FIG. 14  depicts a side elevation view in section showing a mechanical relationship between the anvil, elongate channel, and staple cartridge in the closed position of the surgical stapling and severing instrument of  FIG. 1 , the section generally taken along lines  14 — 14  of  FIG. 10  to expose wedge sled, staple drivers and staples but also depicting the firing bar along the longitudinal centerline. 
       FIG. 15  depicts a section view of the end effector of the surgical stapling and severing instrument with the cartridge and firing bar in the start position taken along line  15 — 15  of  FIG. 10 . 
       FIG. 16  depicts a section view taken along line  16 — 16  of  FIG. 15  showing the cross-sectional relationship between the firing bar, elongate channel, wedge sled, staple drivers, staples and staple cartridge. 
       FIG. 17  depicts a side elevation section view of the surgical stapling and severing instrument of  FIG. 1  taken along the longitudinal centerline of the end effector in a partially closed but unclamped position gripping tissue. 
       FIG. 18  depicts a partially cut-away side elevational view of the surgical stapling and severing instrument of  FIG. 1  in the closed or clamped position. 
       FIG. 19  depicts a side elevation view in centerline section of the distal end of the surgical stapling and severing instrument of  FIG. 1  in the closed or clamped position with tissue properly compressed. 
       FIG. 20  depicts a partially cut-away side elevation view of the surgical stapling and severing instrument of  FIG. 1  in a partially fired position. 
       FIG. 21  depicts a view in centerline section of the distal end of the surgical stapling and severing instrument of  FIG. 1  in a partially fired position. 
       FIG. 22  depicts a partially cut-away side elevation view of the surgical stapling and severing instrument of  FIG. 1  in a fully fired position. 
       FIG. 23  depicts a view in centerline section of the distal end of the surgical stapling and severing instrument of  FIG. 1  in a fully fired position. 
       FIG. 24  depicts a perspective bottom view looking distally at the elongate channel partially cut away to expose part of a cartridge body and a spent cartridge lockout mechanism engaging a middle pin of a firing bar. 
       FIGS. 25–28  depict a cross-sectional side detail view of the spent cartridge lockout mechanism, staple cartridge and firing bar of  FIG. 24 , sequentially shown in a cartridge loaded and unfired state in  FIG. 25 , a cartridge being fired state in  FIG. 26 , a spent cartridge with firing bar being retracted state in  FIG. 27 , and spent cartridge with firing bar retracted state in  FIG. 28 . 
       FIG. 29  depicts a bottom perspective view of a partially cut-away cartridge body to expose an integral spent cartridge lockout mechanism. 
       FIGS. 30–33  depict a cross-sectional side detail view of the integral spent cartridge lockout mechanism of  FIG. 29 , sequentially shown in a cartridge loaded and unfired state in  FIG. 30 , a cartridge being fired state in  FIG. 31 , a spent cartridge with firing bar being retracted state in  FIG. 32 , and a spent cartridge with firing bar retracted state in  FIG. 33 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning to the Drawings, wherein like numerals denote like components throughout the several views,  FIGS. 1 and 2  depict a surgical stapling and severing instrument  10  that is capable of practicing the unique benefits of the present invention. The surgical stapling and severing instrument  10  incorporates an end effector  12  having an E-beam firing mechanism (“firing bar”)  14  that advantageously controls the spacing of the end effector  12 . In particular, an elongate channel  16  and a pivotally translatable anvil  18  are maintained at a spacing that assures effective stapling and severing. Furthermore, firing (i.e., severing and stapling) is prevented from occurring if the instrument is not capable of stapling with a single lockout mechanism, which is described in more detail below. 
   The surgical and stapling and severing instrument  10  includes a handle portion  20  connected to an implement portion  22 , the latter further comprising a shaft  23  distally terminating in the end effector  12 . The handle portion  20  includes a pistol grip  24  toward which a closure trigger  26  is pivotally drawn by the clinician to cause clamping, or closing, of the anvil  18  toward the elongate channel  16  of the end effector  12 . A firing trigger  28  is farther outboard of the closure trigger  26  and is pivotally drawn by the clinician to cause the stapling and severing of clamped tissue in the end effector  12 . 
   It will be appreciated that the terms “proximal” and “distal” are used herein with reference to a clinician gripping a handle of an instrument. Thus, the end effector  12  is distal with respect to the more proximal handle portion  20 . It will be further appreciated that for convenience and clarity, spatial terms such as “vertical” and “horizontal” are used herein with respect to the drawings. However, surgical instruments are used in many orientations and positions, and these terms are not intended to be limiting and absolute. 
   Closure trigger  26  is actuated first. Once the clinician is satisfied with the positioning of the end effector  12 , the clinician may draw back the closure trigger  26  to its fully closed, locked position proximate to the pistol grip  24 . Then, the firing trigger  28  is actuated. The firing trigger  28  springedly returns when the clinician removes pressure. A release button  30  when depressed on the proximal end of the handle portion  20  releases any locked closure trigger  26 . 
   A closure sleeve  32  encloses a frame  34 , which in turn encloses a firing drive member  36  that is positioned by the firing trigger  28 . The frame  34  connects the handle portion  20  to the end effector  12 . With the closure sleeve  32  withdrawn proximally by the closure trigger  26  as depicted, the anvil  18  springedly opens, pivoting away from the elongate channel  16  and translating proximally with the closure sleeve  32 . 
   The elongate channel  16  receives a staple cartridge  37  that is responsive to the firing bar  14  to drive staples into forming contact with the anvil  18 . It will appreciated that although a readily replaceable staple cartridge  37  is advantageously described herein, a staple cartridge  37  consistent with aspects of the present invention may be permanently affixed or integral to the elongate channel  16 , for instance when a larger portion of the end effector  12  is replaced after each firing. 
   E-Beam Firing Mechanism 
   With particular reference to  FIGS. 2–4 , the firing bar  14  includes three vertically spaced pins that control the spacing of the end effector  12  during firing. In particular, an upper pin  38  is staged to enter an anvil pocket  40  near the pivot between the anvil  18  and elongate channel  16 . When fired with the anvil  18  closed, the upper pin  38  advances distally within a longitudinal anvil slot  42  extending distally through anvil  18 . Any minor upward deflection in the anvil  18  is overcome by a downward force imparted by the upper pin  38 . 
   Firing bar  14  also includes a lower most pin, or firing bar cap,  44  that upwardly engages a channel slot  45  in the elongate channel  16 , thereby cooperating with the upper pin  38  to draw the anvil  18  and the elongate channel  16  slightly closer together in the event of excess tissue clamped therebetween. 
   The firing bar  14  advantageously includes a middle pin  46  that passes through a firing drive slot  47  formed in a lower surface of the cartridge  37  and an upward surface of the elongate channel  16 , thereby driving the staples therein as described below. The middle pin  46 , by sliding against the elongate channel  16 , advantageously resists any tendency for the end effector  12  to be pinched shut at its distal end. To illustrate an advantage of the middle pin  46 ,  FIG. 5  depicts an alternative end effector  12 ′ that lacks a middle pin on a firing bar  14 ′. In this depiction, the end effector  12 ′ is allowed to pinch shut at its distal end, which tends to impair desired staple formation. 
   Returning to  FIGS. 2–4 , a distally presented cutting edge  48  between the upper and middle pins  38 ,  46  on the firing bar  14  traverses through a proximally presented, vertical slot  49  in the cartridge  37  to sever clamped tissue. The affirmative positioning of the firing bar  14  with regard to the elongate channel  16  and anvil  18  assure that an effective cut is performed. 
   Cambered Anvil with Selected Cartridge Gap 
   The affirmative vertical spacing provided by the E-Beam firing bar  14  is suitable for the limited size available for endoscopic devices. Moreover, the E-Beam firing bar  14  enables fabrication of an anvil  16  with a camber imparting a vertical deflection at its distal end, similar to the position depicted in  FIG. 5 . This cambered anvil  16  advantageously assists in achieving the desired gap in the end effector  12  even with an anvil  16  reduced thickness, which is thus more suited to the size limitations of an endoscopic device. 
   The E-Beam firing bar  14  further enables increased applications, especially in combination with a range of configurations of staple cartridges. For instance, a clinician may select a gray staple cartridge yielding a 0.02 mm tissue gap, a white staple cartridge yielding a 0.04 mm tissue gap, a blue cartridge yielding a 0.06 mm tissue gap, or a green cartridge yielding a 0.10 mm tissue gap. The vertical height of each respective staple cartridge in combination with the length of staples and an integral wedge sled (described in more detail below) predetermines this desired tissue thickness with the anvil  18  appropriately vertically spaced by the E-Beam firing bar  14 . 
   Two-Axis Handle 
   With reference to  FIGS. 6–9 , the handle portion  20  is comprised of first and second base sections  50  and  52 , which are molded from a polymeric material such as a glass-filled polycarbonate. The first base section  50  is provided with a plurality of cylindrical-shaped pins  54 . The second base section  52  includes a plurality of extending members  56 , each having a hexagonal-shaped opening  58 . The cylindrical-shaped pins  54  are received within the hexagonal-shaped openings  58  and are frictionally held therein for maintaining the first and second base sections  50  and  52  in assembly. 
   A rotating knob  60  has a bore  62  extending completely through it for engaging and rotating the implement portion  22  about its longitudinal axis. The rotating knob  60  includes an inwardly protruding boss  64  extending along at least a portion of the bore  62 . The protruding boss  64  is received within a longitudinal slot  66  formed at a proximal portion of the closure sleeve  32  such that rotation of the rotating knob  60  effects rotation of the closure sleeve  32 . It will be appreciated that the boss  64  further extends through frame  34  and into contact with a portion of the firing drive member  36  to effect their rotation as well. Thus, the end effector  12  (not shown in  FIGS. 6–9 ) rotates with the rotating knob  60 . 
   A proximal end  68  of the frame  34  passes proximally through the rotating knob  60  and is provided with a circumferential notch  70  that is engaged by opposing channel securement members  72  extending respectively from the base sections  50  and  52 . Only the channel securement member  72  of the second base section  52  is shown. The channel securement members  72  extending from the base sections  50 ,  52  serve to secure the frame  34  to the handle portion  20  such that the frame  34  does not move longitudinally relative to the handle portion  20 . 
   The closure trigger  26  has a handle section  74 , a gear segment section  76 , and an intermediate section  78 . A bore  80  extends through the intermediate section  78 . A cylindrical support member  82  extending from the second base section  52  passes through the bore  80  for pivotably mounting the closure trigger  26  on the handle portion  20 . A second cylindrical support member  83  extending from the second base section  52  passes through a bore  81  of firing trigger  28  for pivotally mounting on the handle portion  20 . A hexagonal opening  84  is provided in the cylindrical support member  83  for receiving a securement pin (not shown) extending from the first base section  50 . 
   A closure yoke  86  is housed within the handle portion  20  for reciprocating movement therein and serves to transfer motion from the closure trigger  26  to the closure sleeve  32 . Support members  88  extending from the second base section  52  and securement member  72 , which extends through a recess  89  in the yoke  86 , support the yoke  86  within the handle portion  20 . 
   A proximal end  90  of the closure sleeve  32  is provided with a flange  92  that is snap-fitted into a receiving recess  94  formed in a distal end  96  of the yoke  86 . A proximal end  98  of the yoke  86  has a gear rack  100  that is engaged by the gear segment section  76  of the closure trigger  26 . When the closure trigger  26  is moved toward the pistol grip  24  of the handle portion  20 , the yoke  86  and, hence, the closure sleeve  32  move distally, compressing a spring  102  that biases the yoke  86  proximally. Distal movement of the closure sleeve  32  effects pivotal translation movement of the anvil  18  distally and toward the elongate channel  16  of the end effector  12  and proximal movement effects closing, as discussed below. 
   The closure trigger  26  is forward biased to an open position by a front surface  130  interacting with an engaging surface  128  of the firing trigger  28 . Clamp first hook  104  that pivots top to rear in the handle portion  20  about a pin  106  restrains movement of the firing trigger  28  toward the pistol grip  24  until the closure trigger  26  is clamped to its closed position. Hook  104  restrains firing trigger  28  motion by engaging a lockout pin  107  in firing trigger  28 . The hook  104  is also in contact with the closure trigger  26 . In particular, a forward projection  108  of the hook  104  engages a member  110  on the intermediate section  78  of the closure trigger  26 , the member  110  being outward of the bore  80  toward the handle section  74 . Hook  104  is biased toward contact with member  110  of the closure trigger  26  and engagement with lockout pin  107  in firing trigger  28  by a release spring  112 . As the closure trigger  26  is depressed, the hook  104  is moved top to rear, compressing the release spring  112  that is captured between a rearward projection  114  on the hook  104  and a forward projection  116  on the release button  30 . 
   As the yoke  86  moves distally in response to proximal movement of the closure trigger  26 , an upper latch arm  118  of the release button  30  moves along an upper surface  120  on the yoke  86  until dropping into an upwardly presented recess  122  in a proximal, lower portion of the yoke  86 . The release spring  112  urges the release button  30  outward, which pivots the upper latch arm  118  downwardly into engagement with the upwardly presented recess  122 , thereby locking the closure trigger  26  in a tissue clamping position, such as depicted in  FIG. 8 . 
   The latch arm  118  can be moved out of the recess  122  to release the anvil  18  by pushing the release button  30  inward. Specifically, the upper latch arm  118  pivots upward about pin  123  of the second base section  52 . The yoke  86  is then permitted to move proximally in response to return movement of the closure trigger  26 . 
   A firing trigger return spring  124  is located within the handle portion  20  with one end attached to pin  106  of the second base section  52  and the other end attached to a pin  126  on the firing trigger  28 . The firing return spring  124  applies a return force to the pin  126  for biasing the firing trigger  28  in a direction away from the pistol grip  24  of the handle portion  20 . The closure trigger  26  is also biased away from pistol grip  24  by engaging surface  128  of firing trigger  28  biasing front surface  130  of closure trigger  26 . 
   As the closure trigger  26  is moved toward the pistol grip  24 , its front surface  130  engages with the engaging surface  128  on the firing trigger  28  causing the firing trigger  28  to move to its “firing” position. When in its firing position, the firing trigger  28  is located at an angle of approximately 45° to the pistol grip  24 . After staple firing, the spring  124  causes the firing trigger  28  to return to its initial position. During the return movement of the firing trigger  28 , its engaging surface  128  pushes against the front surface  130  of the closure trigger  26  causing the closure trigger  26  to return to its initial position. A stop member  132  extends from the second base section  52  to prevent the closure trigger  26  from rotating beyond its initial position. 
   The surgical stapling and severing instrument  10  additionally includes a reciprocating section  134 , a multiplier  136  and a drive member  138 . The reciprocating section  134  comprises a wedge sled in the implement portion  22  (not shown in  FIGS. 6–9 ) and a metal drive rod  140 . 
   The drive member  138  includes first and second gear racks  141  and  142 . A first notch  144  is provided on the drive member  138  intermediate the first and second gear racks  141 ,  142 . During return movement of the firing trigger  28 , a tooth  146  on the firing trigger  28  engages with the first notch  144  for returning the drive member  138  to its initial position after staple firing. A second notch  148  is located at a proximal end of the metal drive rod  140  for locking the metal drive rod  140  to the upper latch arm  118  of the release button  30  in its unfired position. 
   The multiplier  136  comprises first and second integral pinion gears  150  and  152 . The first integral pinion gear  150  is engaged with a first gear rack  154  provided on the metal drive rod  140 . The second integral pinion gear  152  is engaged with the first gear rack  141  on the drive member  138 . The first integral pinion gear  150  has a first diameter and the second integral pinion gear  152  has a second diameter which is smaller than the first diameter. 
     FIGS. 6 ,  8  and  9  depict respectively the handle portion  20  in the start position (open and unfired), a clamped position (closed and unfired) and a fired position. The firing trigger  28  is provided with a gear segment section  156 . The gear segment section  156  engages with the second gear rack  142  on the drive member  138  such that motion of the firing trigger  28  causes the drive member  138  to move back and forth between a first drive position, shown in  FIG. 8 , and a second drive position, shown in  FIG. 9 . In order to prevent staple firing before tissue clamping has occurred, the upper latch arm  118  on the release button  30  is engaged with the second notch  148  on the drive member  138  such that the metal drive rod  140  is locked in its proximal-most position, as depicted in  FIG. 6 . When the upper latch arm  118  falls into the recess  122 , the upper latch arm  118  disengages with the second notch  148  to permit distal movement of the metal drive rod  140 , as depicted in  FIG. 9 . 
   Because the first gear rack  141  on the drive member  138  and the gear rack  154  on the metal drive rod  140  are engaged with the multiplier  136 , movement of the firing trigger  28  causes the metal drive rod  140  to reciprocate between a first reciprocating position, shown in  FIG. 8 , and a second reciprocating position, shown in  FIG. 9 . Since the diameter of the first pinion gear  150  is greater than the diameter of the second pinion gear  152 , the multiplier  136  moves the reciprocating section  134  a greater distance than the drive member  138  is moved by the firing trigger  28 . The diameters of the first and second pinion gears  150  and  152  may be changed to permit the length of the stroke of the firing trigger  28  and the force required to move it to be varied. 
   It will be appreciated that the handle portion  20  is illustrative and that other actuation mechanisms may be employed. For instance, the closing and firing motions may be generated by automated means. 
   Separate and Distinct Closing and Firing End Effector 
   The end effector  12  of the surgical stapling and severing instrument  10  is depicted in further detail in  FIGS. 1–16 . As described above, the handle portion  20  produces separate and distinct closing and firing motions that actuate the end effector  12 . The end effector  12  advantageously maintains the clinical flexibility of this separate and distinct closing and firing (i.e., stapling and severing). In addition, the end effector  12  introduces the aforementioned ability to affirmatively maintain the closed spacing during firing after the clinician positions and clamps the tissue. Both features procedurally and structurally enhance the ability of the surgical stapling and severing instrument  10  by ensuring adequate spacing for instances where an otherwise inadequate amount of tissue is clamped and to enhance the clamping in instances where an otherwise excessive amount of tissue has been clamped. 
     FIG. 10  depicts the end effector  12 , which is in an open position by a retracted closure sleeve  32 , with a staple cartridge  37  installed in the elongate channel  16 . On a lower surface  200  of the anvil  18 , a plurality of stapling forming pockets  202  are arrayed to correspond to a plurality of stapler apertures  204  in an upper surface  206  of the staple cartridge  37 . The firing bar  14  is at its proximal position, with the upper pin  38  aligned in a noninterfering fashion with the anvil pocket  40 . The anvil pocket  40  is shown as communicating with the longitudinal anvil slot  42  in the anvil  18 . The distally presented cutting edge  48  of the firing bar  14  is aligned with and proximally from removed from the vertical slot  49  in the staple cartridge  37 , thereby allowing removal of a spent cartridge and insertion of an unfired cartridge, which is snapfit into the elongate channel  16 . Specifically, extension features  208 ,  210  of the staple cartridge  37  engage recesses  212 ,  214  (shown in  FIG. 12 ) of the elongate channel  16 . 
     FIG. 11  shows the implement portion  22  of the surgical stapling and severing instrument  10  in disassembled form. The staple cartridge  37  is shown as being comprised of a cartridge body  216 , a wedge sled  218 , single and double drivers  220 , staples  222 , and a cartridge tray  224 . When assembled, the cartridge tray  224  holds the wedge sled  218 , single and double drivers  220 , and staples  222  inside the cartridge body  216 . 
   Having a wedge sled  218  integral to the staple cartridge  37  enables a number of flexible design options as compared to incorporating camming surfaces onto a firing bar itself. For instance, a number of different staple cartridges may be selected for use in the instrument  10  with each staple cartridge having a different configuration of rows of staples, each thus having a unique wedge sled configured to contact the middle pin  46  of the firing bar  14  while causing the driving of the staples  222 . As another example, the integral wedge sled  218  provides an opportunity for a number of lockout features, described in greater detail in the first and third aforementioned co-pending applications. 
   The elongate channel  16  has a proximally placed attachment cavity  226  that receives a channel anchoring member  228  on the distal end of the frame  34  for attaching the end effector  12  to the handle portion  20 . The elongate channel  16  also has an anvil cam slot  230  that pivotally receives an anvil pivot  232  of the anvil  18 . The closure sleeve  32  that encompasses the frame  34  includes a distally presented tab  234  that engages an anvil feature  236  proximate but distal to the anvil pivot  232  on the anvil  18  to thereby effect opening and closing of the anvil  18 . The firing drive member  36  is shown as being assembled from the firing bar  14  attached to a firing connector  238  by pins  240 , which in turn is rotatingly and proximally attached to the metal drive rod  140 . The firing bar  14  is guided at a distal end of the frame by a slotted guide  239  inserted therein. 
   With particular reference to  FIG. 12 , a portion of the staple cartridge  37  is removed to expose portions of the elongate channel  16 , such as recesses  212 ,  214  and to expose some components of the staple cartridge  37  in their unfired position. In particular, the cartridge body  216  (shown in  FIG. 11 ) has been removed. The wedge sled  218  is shown at its proximal, unfired position with a pusher block  242  contacting the middle pin  46  (not shown in  FIG. 12 ) of the firing bar  14 . The wedge sled  218  is in longitudinal sliding contact upon the cartridge tray  224  and includes wedges  228  that force upward the single and double drivers  220  as the wedge sled  218  moves distally. Staples  222  (not shown in  FIG. 12 ) resting upon the drivers  220  are thus also forced upward into contact with the anvil forming pockets  202  on the anvil  18  to form closed staples. Also depicted is the channel slot  45  in the elongate channel  16  that is aligned with the vertical slot  49  in the staple cartridge  37 . 
     FIG. 13  depicts the end effector  12  of  FIG. 12  with all of the staple cartridge  37  removed to show the middle pin  46  of the firing bar  14  as well as portion of the elongate channel  16  removed adjacent to the channel slot  45  to expose the firing bar cap  44 . In addition, portions of the shaft  23  are removed to expose a proximal portion of the firing bar  14 . Projecting downward from the anvil  18  near the pivot, a pair of opposing tissue stops  244  prevent tissue being positioned too far up into the end effector  12  during clamping. 
     FIG. 14  depicts the end effector  12  closed in a tissue clamping position with the firing bar  14  unfired. The upper pin  38  is in the anvil pocket  40 , vertically aligned with the anvil slot  42  for distal longitudinal movement of the firing bar  14  during firing. The middle pin  46  is positioned to push the wedge sled  218  distally so that wedge  228  sequentially contacts and lifts double drivers  220  and the respective staples  222  into forming contact with staple forming pockets  202  in the lower surface  200  of the anvil  18 . 
     FIG. 15  depicts the upper surface  206  of the staple cartridge  37  with the firing bar  14  in its unfired, proximal position. The stapler apertures  204  are arrayed on each side of the vertical slot  49  in the staple cartridge  37 . 
     FIG. 16  depicts the end effector  12  near the pivot showing that the elongate channel  16  has opposing ramp portions  246  to thereby cooperate with the tissue stops  244  of the anvil  18  (not shown in  FIG. 16 ) to prevent tissue from jamming the end effector  12 . Also depicted in greater detail are the double drivers  220  and their relation to the staples  222 . 
   Operation 
   In use, the surgical stapling and severing instrument  10  is used as depicted in  FIGS. 1 ,  2 , and  17 – 23 . In  FIGS. 1–2 , the instrument  10  is in its start position, having had an unfired, fully loaded staple cartridge  37  snap-fitted into the distal end of the elongate channel  16 . Both triggers  26 ,  28  are forward and the end effector  12  is open, such as would be typical after inserting the end effector  12  through a trocar or other opening into a body cavity. The instrument  10  is then manipulated by the clinician such that tissue  248  to be stapled and severed is positioned between the staple cartridge  37  and the anvil  18 , as depicted in  FIG. 17 . 
   With reference to  FIGS. 18–19 , next, the clinician moves the closure trigger  26  proximally until positioned directly adjacent to the pistol grip  24 , locking the handle portion  20  into the closed and clamped position. The retracted firing bar  14  in the end effector  12  does not impede the selective opening and closing of the end effector  12 , but rather resides within the anvil pocket  40 . With the anvil  18  closed and clamped, the E-beam firing bar  14  is aligned for firing through the end effector  12 . In particular, the upper pin  38  is aligned with the anvil slot  42  and the elongate channel  16  is affirmatively engaged about the channel slot  45  by the middle pin  46  and the firing bar cap  44 . 
   With reference to  FIGS. 20–21 , after tissue clamping has occurred, the clinician moves the firing trigger  28  proximally causing the firing bar  14  to move distally into the end effector  12 . In particular, the middle pin  46  enters the staple cartridge  37  through the firing drive slot  47  to effect the firing of the staples  222  (not shown in  FIGS. 20–21 ) via wedge sled  218  toward the anvil  18 . The lower most pin, or firing bar cap  44 , cooperates with the middle pin  46  to slidingly position cutting edge  48  of the firing bar  14  to sever tissue. The two pins  44 ,  46  also position the upper pin  38  of the firing bar  14  within longitudinal anvil slot  42  of the anvil  18 , affirmatively maintaining the spacing between the anvil  18  and the elongate channel  16  throughout its distal firing movement. 
   With reference to  FIGS. 22–23 , the clinician continues moving the firing trigger  28  until brought proximal to the closure trigger  26  and pistol grip  24 . Thereby, all of the ends of the staples  222  are bent over as a result of their engagement with the anvil  18 . The firing bar cap  44  is arrested against a firing bar stop  250  projecting toward the distal end of the channel slot  45 . The cutting edge  48  has traversed completely through the tissue. The process is complete by releasing the firing trigger  28  and by then depressing the release button  30  while simultaneously squeezing the closure trigger  26  to open the end effector  12 . 
   While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications may readily appear to those skilled in the art. 
   For example, the affirmative spacing of the anvil  18  and elongate channel  16  is achieved in part with two pins  44 ,  46  on the firing bar  14  engaging opposite sides of a channel slot  47  and a single upper pin  38  entrained within an anvil slot  42 . It would consistent with aspects of the invention for the anvil to be captured by opposing pins on either side of a longitudinal slot and/or for an elongate channel to have an internal slot that entrains a lower pin. 
   For another example, although the E-beam firing beam  14  has advantages for an endoscopically employed surgical severing and stapling instrument  10 , a similar E-Beam may be used in other clinical procedures. It is generally accepted that endoscopic procedures are more common than laparoscopic procedures. Accordingly, the present invention has been discussed in terms of endoscopic procedures and apparatus. However, use herein of terms such as “endoscopic”, should not be construed to limit the present invention to a surgical stapling and severing instrument for use only in conjunction with an endoscopic tube (i.e., trocar). On the contrary, it is believed that the present invention may find use in any procedure where access is limited to a small incision, including but not limited to laparoscopic procedures, as well as open procedures. 
   For yet another example, although an illustrative handle portion  20  described herein is manually operated by a clinician, it is consistent with aspects of the invention for some or all of the functions of a handle portion to be powered (e.g., pneumatic, hydraulic, electromechanical, ultrasonic, etc.). Furthermore, controls of each of these functions may be manually presented on a handle portion or be remotely controlled (e.g., wireless remote, automated remote console, etc.). 
   As yet an additional example, although a simultaneous stapling and severing instrument is advantageously illustrated herein, it would be consistent with aspects of the invention for stapling to comprise other types of fasteners and attachment techniques. 
   Spent Cartridge Lockout 
   As described above, the E-beam firing bar  14  provides unique capabilities for affirmatively spacing the end effector  12  while simultaneously severing tissue and effecting the forming of staples on each side of the cut. Preventing the distal movement of the firing bar  14  thus prevents the inadvertent severing of tissue. A spent cartridge lockout mechanism  270  advantageously responds to a spent staple cartridge  37  by blocking the middle pin  46  of the firing bar  14  (only the middle pin of the firing bar being shown in  FIG. 24 ). 
   In particular, the spent cartridge mechanism  270  is depicted as being incorporated into a cartridge body  272  with blocking members  274  resiliently positioned above the wedge sled  218  (not shown in  FIG. 24 ). In particular, the blocking members  274  each reside within a downward and proximally opening cavity  276 . Each block member  274  includes a leaf spring end  277  that is held within the cavity  276 . 
   The cavities  276  are vertically aligned and spaced and parallel about the vertical slot  49 . The cartridge body  272  also includes wedge slots  278  that longitudinally pass through the cartridge, being open from a portion of a proximal and underside of the cartridge body  272  to receive individual wedges of the wedge sled  218  (not shown in  FIG. 24 ). 
   Each lockout mechanism  270  has a deflectable end  280  shaped to reside within the respective cavity  276  when depressed and to impede a distally moving middle pin  46  of a firing bar  14  when released. 
     FIGS. 25–28  depict the lockout mechanism  270  sequentially as the surgical stapling and severing instrument  10  is fired. In  FIG. 25 , an unfired staple cartridge  37  has been inserted into the elongate channel  16  with the wedge sled  218  depressing upward the deflectable ends  280  so that the firing drive slot  47  formed between the cartridge  37  and the elongate channel  16  is unimpeded. 
   In  FIG. 26 , firing of the cartridge  37  has commenced, with the wedge sled  218  and the middle pin  46  of the firing bar  14  having distally traversed past the deflectable ends  280 , which then spring down into the firing drive slot  47 . 
   In  FIG. 27 , the staple cartridge  37  is now spent with the wedge sled  218  fully driven distally and no longer depicted. The firing bar  14  is being retracted proximally. Since the deflectable ends  280  pivot from a more distal point, the firing bar  14  is able to ride under the deflectable ends  280  during retraction, causing them to be depressed up, out of the firing drive slot  47 . 
   In  FIG. 28 , the firing bar  14  is fully retracted and now confronts a non-depressed (released) pair of deflectable ends  280  to prevent distal movement. The single lockout mechanism  270  thereby activated remains during the period in which the spent staple cartridge  37  is removed until an unfired staple cartridge  37  is installed. 
     FIG. 29  depicts another lockout mechanism  290 , depicted as an integral lockout hook  292  formed as part of a cartridge body  294 . In particular, a proximally directed wedge shaped recess  296  defines proximally directed shaft  298  that terminates in a downwardly projecting hook end  300 . It will be appreciated that the cartridge body  294  is depicted partially cut away showing only one lockout hook  292 , although a pair may advantageously be used, one on each side of the vertical slot  49  (not shown in  FIG. 29 ). Thus, the lockout mechanism  290  may be economically incorporated into a staple cartridge  37  without additional assembly steps. 
     FIGS. 30–33  depict the sequence of operation of the integral lockout hooks  290 . In  FIG. 30 , the staple cartridge  37  is unfired so that the distally positioned wedge sled  218  depresses upwardly the hook ends  300  into the wedge shaped recess  296 , allowing the middle pin  46  of the firing bar  14  to move distally during firing, as depicted in  FIG. 31 . With the wedge sled  218  and middle pin  46  distally removed with respect to the lockout hooks  292 , the lockout hooks  292  resiliently returns to its released position, with hooks end  300  occupying the firing drive slot  47 . 
   In  FIG. 32 , the firing bar  14  is being retracted to the point of contacting the hook ends  300  of the lockout hook  292 . Since the distal edge of the hook ends  300  is ramped downward proximally, the middle pin  46  of the firing bar  14  rides under the hook ends  300 , forcing them up into the wedge shaped recess  296  until middle pin  46  is past the hook ends  300 , as depicted in  FIG. 33  wherein the hook ends  300  resiliently spring back down to block the middle pin  46 . Thus, the firing bar  14  is prevented from distal movement while the spent staple cartridge  37  remains in the elongate channel  16 . 
   While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications may readily appear to those skilled in the art. 
   For example, although a lockout mechanism comprised of a pair of fingers or hooks has been depicted, some applications may rely upon only one such structure. 
   As another example, although the middle pin  46  of the firing bar is engaged by the locking mechanism, in some applications the locking member may impede the another portion of a firing bar, such as a vertical surface or a lower cap. 
   As yet an additional example, although a staple cartridge advantageously allows reuse of most of the end effector, applications of the lockout mechanism may be in disposable end effectors that are replaced after each firing.