Abstract:
A fastener cartridge assembly that comprises a cartridge body, a proximal end, a distal end, a plurality of fastener cavities, a slot configured to receive a cutting member, a row of first fasteners, a row of second fasteners, a first fastener driver, a second fastener driver, and a sled is disclosed. The sled comprises a first ramp configured to lift said first fastener driver and said first fastener toward an anvil. The anvil and said first fastener driver are configured to cooperatively deform said first fastener to a first fired height. The sled further comprises a second ramp configured to lift said second fastener driver and said second fastener toward the anvil. The anvil and said second fastener driver are configured to cooperatively deform said second fastener to a second fired height. The second fired height is different than said first fired height.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application claiming priority under 35 U.S.C. §120 to U.S. patent application Ser. No. 13/020,263, filed Feb. 3, 2011, entitled SURGICAL STAPLING SYSTEMS THAT PRODUCE FORMED STAPLES HAVING DIFFERENT LENGTHS, now U.S. Patent Publication No. 2011/0147434, which is a continuation application claiming priority under 35 U.S.C. §120 to U.S. patent application Ser. No. 11/711,979, filed Feb. 28, 2007, entitled SURGICAL STAPLING DEVICES THAT PRODUCE FORMED STAPLES HAVING DIFFERENT LENGTHS, which issued on Nov. 27, 2012 as U.S. Pat. No. 8,317,070, which is a continuation-in-part patent application claiming priority under 35 U.S.C. §120 of U.S. patent application Ser. No. 11/216,562, filed Aug. 31, 2005, entitled STAPLE CARTRIDGES FOR FORMING STAPLES HAVING DIFFERING FORMED STAPLE HEIGHTS, which issued on Mar. 2, 2010 as U.S. Pat. No. 7,669,746, the entire disclosures of which are hereby incorporated by reference herein. 
     The present application is also related to the following, U.S. patent applications, which are incorporated herein by reference:
         (1) SURGICAL STAPLING DEVICE WITH STAPLE DRIVER THAT SUPPORTS MULTIPLE WIRE DIAMETER STAPLES, U.S. patent application Ser. No. 11/711,977, now U.S. Pat. No. 7,673,781;   (2) SURGICAL STAPLING DEVICE WITH ANVIL HAVING STAPLE FORMING POCKETS OF VARYING DEPTH, U.S. patent application Ser. No. 11/714,049, now U.S. Patent Publication No. 2007/0194082;   (3) SURGICAL STAPLING DEVICE WITH MULTIPLE STACKED ACTUATOR WEDGE CAMS FOR DRIVING STAPLE DRIVERS, U.S. patent application Ser. No. 11/712,315, now U.S. Pat. No. 7,500,979;   (4) SURGICAL STAPLING DEVICE WITH STAPLE DRIVERS OF DIFFERENT HEIGHT, U.S. patent application Ser. No. 11/711,975, now U.S. Patent Publication No. 2007/0194079; and   (5) STAPLE CARTRIDGES FOR FORMING STAPLES HAVING DIFFERING FORMED STAPLE HEIGHTS, U.S. patent application Ser. No. 12/695,359, now U.S. Pat. No. 8,464,923.       

    
    
     FIELD OF THE INVENTION 
     The present invention relates in general to stapling instruments that are capable of applying lines of staples and, more particularly, to improvements relating to staple cartridges for use with surgical stapling instruments that are capable of applying lines of staples having differing formed staple heights to tissue while simultaneously cutting the tissue. 
     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 that, 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. Patent Application No. 2004/0232196 A1, the disclosure of which is herein incorporated by reference in its entirety. In use, a clinician is able to close the jaw members of the stapler 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. 
     Whenever a transsection of tissue is across an area of varied tissue composition, it would be advantageous for the staples that are closest to the cut line to have one formed height that is less than the formed height of those staples that are farthest from the cut line. In practice, the rows of inside staples serve to provide a hemostatic barrier, while the outside rows of staples with larger formed heights provide a cinching effect where the tissue transitions from the tightly compressed hemostatic section to the non-compressed adjacent section. In other applications, it may be useful for the staples in a single line of staples to have differing formed heights. U.S. Pat. Nos. 4,941,623 and 5,027,834 to Pruitt disclose surgical stapler and cartridge arrangements that employ staples that have different prong lengths to ultimately achieve lines of staples that have differing formed heights. Likewise, WO 2003/094747A1 discloses a surgical stapler and cartridge that has six rows of staples wherein the outer two rows of staples comprise staples that are larger than the staples employed in the inner two rows and middle rows of staples. Thus, all of these approaches require the use of different sizes of staples in the same cartridge. 
     BRIEF SUMMARY OF THE INVENTION 
     In one general aspect, the present invention is directed to surgical stapling devices that are capable of producing staples of different formed lengths. For example, in such a device that also cuts the tissue being stapled, the inside rows of staples closest to the longitudinal incision line could have a formed height that is less than the formed height of the outer rows of staples. That way, the inside rows of staples may provide a hemostatic barrier, while the outside rows of staples with larger formed heights may provide a cinching effect where the tissue transitions from the tightly compressed hemostatic section to the non-compressed adjacent section. 
     According to various implementations, the staple cartridge may have staple drivers of different heights to product staples having different formed lengths. The staples driven by the shorter staple drivers would have longer formed lengths (assuming no other differences that would affect the formed heights of the staples). Also, the staple forming pockets in the anvil may have different depths. Staples formed in deeper pockets would tend to be longer than staples formed in shallow pockets. In addition, some of the staple forming pockets may be formed in compliant material portions of the anvil. Staples formed in such pockets would tend to be longer than staples formed in a non-compliant (or less compliant) portion of the anvil. Additionally, the channel may have internal steps that would produce staples having different formed heights. Staples formed with staple drivers starting at a lower step would have a longer formed length that stapled formed with staple drivers starting at a higher step. Also, staples with different wire diameters may be used. Thicker staples would tend to produce staples with longer formed lengths. In that connection, embodiments of the present invention are directed to staple pushers that can accommodate staples of varying wire thicknesses. Also, staples of differing materials could be used. Staples made of stronger, less compliant materials, would tend to produce longer formed staples. 
     According to other embodiments, the surgical stapling device may comprise a plurality of stacked wedge band sets. Each stacked wedge band set may comprise a number of wedge bands stacked one on another. The wedge bands may be actuated in succession in order to drive the staples in successive stages. That is, for example, in an embodiment having three wedge bands in a stack, the first wedge band may be actuated first to partially deploy the staples, the second wedge band in stack may be actuated next to begin to form the staples, and the third wedge band in the stack may be actuated last to finish the formation of the staples. To produce staples having different formed heights, the heights of the stacks (corresponding to the cumulative height of the wedge bands in the stacks) may be different, for example. 
     The techniques used to create formed staples of different heights could be used in a variety of different surgical stapling devices. For example, the stapling devices could be devices that cut the clamped tissue or devices that include no cutting instrument. The surgical staplers may be, for example, endocutters, open linear stapler devices, or circular staplers. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate by way of example 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, wherein: 
         FIG. 1  depicts a partially cut away side elevation view of a surgical stapling and severing instrument in an open position according to various embodiments of the present invention; 
         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 according to various embodiments of the present invention; 
         FIG. 3  depicts an enlarged side elevation view of the firing bar of the surgical stapling and severing instrument of  FIG. 2  according to various embodiments of the present invention; 
         FIG. 4  depicts an enlarged front view of the firing bar of the surgical stapling and severing instrument of  FIG. 2  according to various embodiments of the present invention; 
         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, according to various embodiments of the present invention; 
         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 according to various embodiments of the present invention; 
         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  according to various embodiments of the present invention; 
         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 according to various embodiments of the present invention; 
         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 according to various embodiments of the present invention; 
         FIG. 10  depicts a plan view of a staple cartridge installed in an end effector according to various embodiments of the present invention; 
         FIG. 11  is an enlarged plan view of a portion of a staple cartridge according to various embodiments of the present invention; 
         FIG. 12  is a side view of a staple that may be employed with various embodiments of the present invention; 
         FIG. 13  is a front elevational view of one inside double driver supporting two staples thereon according to various embodiments of the present invention; 
         FIG. 14  is a top view of the inside double driver and staples of  FIG. 13  according to various embodiments of the present invention; 
         FIG. 14A  is an elevational view of the inside double driver of  FIG. 13  within a portion of a staple cartridge mounted in the end effector and also illustrating a corresponding portion of the anvil when in a closed position according to various embodiments of the present invention; 
         FIG. 15  is a right side elevational view of the inside double driver and staples of  FIGS. 13 and 14  according to various embodiments of the present invention; 
         FIG. 15A  is another side elevational view of the inside double driver of  FIG. 15  wherein corresponding portions of the cartridge tray and anvil are illustrated in broken lines to depict the relationships therebetween according to various embodiments of the present invention; 
         FIG. 16  is a front elevational view of one outside single driver supporting a staple thereon according to various embodiments of the present invention; 
         FIG. 16A  is another front view of the outside single driver of  FIG. 16  with portions of the cartridge tray and anvil shown to illustrate the relationships therebetween according to various embodiments of the present invention; 
         FIG. 17  is a top view of the outside single driver and staple of  FIG. 16  according to various embodiments of the present invention; 
         FIG. 18  is an isometric exploded view of the implement portion of the surgical stapling and severing instrument of  FIG. 1  according to various embodiments of the present invention; 
         FIG. 19  is a section view taken along line  19 - 19  of  FIG. 10  showing the cross-sectional relationship between the firing bar, elongate channel, wedge sled, staple drivers, staples and staple cartridge according to various embodiments of the present invention; 
         FIG. 19A  is another cross-sectional view of an end effector showing the cross-sectional relationship between the firing bar, elongate channel, wedge sled, staple drivers, staples, staple cartridge and anvil according to various embodiments of the present invention; 
         FIG. 20  is a perspective view of one wedge sled according to various embodiments of the present invention; 
         FIG. 21  is a side elevational view of an inside sled cam of the wedge sled depicted in  FIG. 20  according to various embodiments of the present invention; 
         FIG. 22  is a side elevational view of an outside sled cam of the wedge sled depicted in  FIG. 20  according to various embodiments of the present invention; 
         FIG. 23  is 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 according to various embodiments of the present invention; 
         FIG. 24  is 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 according to various embodiments of the present invention; 
         FIG. 25  is 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 according to various embodiments of the present invention; 
         FIG. 26  is 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  26 - 26  of  FIG. 24  to expose wedge sled, staple drivers and staples but also depicting the firing bar along the longitudinal centerline according to various embodiments of the present invention; 
         FIG. 27  is a cross-sectional view of a portion of a staple cartridge wherein an outside cam of a wedge is adjacent to an outside single driver according to various embodiments of the present invention; 
         FIG. 28  is a cross-sectional view of a portion of a staple cartridge wherein an outside cam of a wedge sled is engaging three outside single drivers according to various embodiments of the present invention; 
         FIG. 29  is a diagrammatic representation of lines of staples installed on each side of a cut line using a surgical stapling and severing instrument according to various embodiments of the present invention; 
         FIG. 30  depicts a staple formed by one inside driver according to various embodiments of the present invention; 
         FIG. 31  depicts another staple formed by one outside driver according to various embodiments of the present invention; 
         FIG. 32  is a diagrammatic representation of lines of staples installed on each side of a cut line using a surgical stapling and severing instrument according to various embodiments of the present invention; 
         FIG. 33  is a diagrammatic representation of lines of staples installed on each side of a cut line using a surgical stapling and severing instrument according to various embodiments of the present invention; 
         FIG. 34  is a diagrammatic representation of lines of staples installed on each side of a cut line using a surgical stapling and severing instrument according to various embodiments of the present invention; 
         FIG. 35  is 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 according to various embodiments of the present invention; 
         FIG. 36  depicts a partially cut away side elevational view of the surgical stapling and severing instrument of  FIG. 1  in the closed or clamped position according to various embodiments of the present invention; 
         FIG. 37  depicts a side elevation view of the surgical stapling and severing instrument of  FIG. 1  in the closed or clamped position with tissue properly compressed according to various embodiments of the present invention; 
         FIG. 38  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 according to various embodiments of the present invention; 
         FIG. 39  depicts a partially cut away side elevation view of the surgical stapling and severing instrument of  FIG. 1  in a partially fired position according to various embodiments of the present invention; 
         FIG. 40  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 according to various embodiments of the present invention; 
         FIG. 41  is a partially cut-away side elevational view of the surgical stapling and severing instrument of  FIG. 1  in a full fired position according to various embodiments of the present invention; 
         FIGS. 42-44  depict aspects of an end effector having a sled with multiple sled cams where one sled cam is taller than another according to various embodiments of the present invention; 
         FIG. 45  depicts aspects of an end effector with staple forming pockets having varying depths according to various embodiments of the present invention; 
         FIGS. 46-47  depict a double staple driver having staples of different pre-formation lengths according to various embodiments of the present invention; 
         FIG. 48  depicts a side-view of an end effector having a double staple driver having different staple driver heights according to various embodiments of the present invention; 
         FIG. 49-50  depict a side-view of an end effector having staple forming pockets of varying depths according to various embodiments of the present invention; 
         FIGS. 51-62  depict aspects of a surgical stapling device having stacks of actuatable wedge bands according to various embodiments of the present invention; 
         FIGS. 63-69  depict aspects of an open linear surgical stapling device according to various embodiments of the present invention; 
         FIGS. 70-77  depicts cross-sectional front views of an end effector according to various embodiments of the present invention; 
         FIGS. 78-83  depict staple drivers that can accommodate staple having different wire diameters according to various embodiments of the present invention; 
         FIGS. 84-89  depict a circular surgical stapling device according to various embodiments of the present invention; and 
         FIGS. 90-95  depict another surgical stapling device according to embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning to the figures, wherein like numerals denote like components throughout the several views,  FIGS. 1 and 2  depict one embodiment of a surgical stapling and severing instrument  10  that is capable of practicing the unique benefits of the present invention. It should be recognized, however, that the unique and novel aspects of the present invention may be advantageously employed in connection with a variety of other staplers and stapler instruments without departing from the spirit and scope of the present invention. Accordingly, the scope of protection afforded to the various embodiments of the present invention should not be limited to use only with the specific type of surgical stapling and severing instruments described herein. 
     As can be seen in  FIGS. 1 and 2 , the surgical stapling and severing instrument  10  incorporates an end effector  12  having an actuator or 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. The problems are avoided associated with varying amounts of tissue being captured 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. 
     The surgical and stapling and severing instrument  10  includes a handle portion  20  that is 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 . 
     In practice, 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 . 
     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 lowermost 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  300  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. 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  15  with a camber imparting a vertical deflection at its distal end, similar to the position depicted in  FIG. 5 . This cambered anvil  15  advantageously assists in achieving the desired gap in the end effector  12  even with an anvil  15  having a reduced thickness, which may be more suited to the size limitations of an endoscopic device. 
     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 cylindrically-shaped pins  54 . The second base section  52  includes a plurality of extending members  56 , each having a hexagonal-shaped opening  58 . The cylindrically-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  100  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  39  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. 
     One embodiment of an end effector  12  of the surgical stapling and severing instrument  10  is depicted in further detail in  FIGS. 18, 19, and 23-26 . 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 a staple cartridge embodiment  300  of the present invention installed in the end effector  12  with the firing bar  14  in its unfired, proximal position. The staple cartridge  300  has a cartridge body  302  that is divided by an elongated slot  310  that extends from a proximal end  304  of the cartridge  300  towards a tapered outer tip  306 . A plurality of staple-receiving channels  320   a - 320   f  are formed within the staple cartridge body  302  and are arranged in six laterally spaced longitudinal rows  500 ,  502 ,  504 ,  506 ,  508 ,  510 , with three rows on each side of the elongated slot  310 . Positioned within the staple-receiving channels  320   a - 320   f  are the staples  222 . See  FIGS. 10 and 11 . 
     The cartridge  300  further includes four laterally spaced longitudinal rows of staple drivers  330   a ,  330   b ,  370   a , and  370   b  as shown in  FIG. 11 . The “first” inside staple drivers  330   a  are slidably mounted within corresponding channels  320   b  and  320   c  such that each driver  330   a  supports two staples  222 , one in a channel  320   b  and one in a channel  320   c . Likewise, the “second” inside drivers  330   b  are slidably mounted within channels  320   d  and  320   e  such that each driver  330   b  supports two staples  222 , one in a channel  320   d  and one in a channel  320   e . The “outside” drivers  370   a  and  370   b  are slidably mounted within the staple-receiving channels  320   a  and  320   f , respectively. Each of the outside drivers  370   a  and  370   b  supports a single staple  222 . Drivers  370   a  are referred to herein as “first” outside drivers and drivers  370   b  are referred to herein as “second” outside drivers. 
       FIG. 12  illustrates a staple  222  that may be used in connection with the various embodiments of the present invention. The staple  222  includes a main portion  223  and two prongs  225 . The prongs  225  each have a length “P” and the main portion has a width “W”. The reader will appreciate that a variety of different types of staples may be employed. For example, for a vascular staple, “P” may be approximately 0.102 inches; for a regular staple, “P” may be approximately 0.134 inches; and for a thick tissue staple, “P” may be approximately 0.160 inches. “W” may be approximately 0.012 inches. Other sizes of staples  222  may be employed in the manners discussed below. 
     The inside staple drivers  330   a  located on one side of the elongated slot  310  are referred to herein as “first” inside staple drivers and the inside staple drivers  330   b  located on the other side of the elongated slot  310  are referred to herein as “second” inside staple drivers. As will be discussed in further detail below, in one embodiment, the second inside staple drivers  330   b  are identical to the first inside staple drivers  330   a , except for their orientation in their respective channels in the cartridge body  302 . 
       FIGS. 13-15  illustrate one embodiment of a “first” inside double driver  330   a  for supporting and driving staples  222 . As can be seen in those Figures, the staple driver  330   a  has a primary driver portion  340  and a secondary driver portion  350  that is connected to the first primary portion  340  by a central base member  360 . The primary driver portion  340  has a primary driver base  342  that has a groove  343  therein adapted to mate with a corresponding vertically extending tongue (not shown) in the cartridge body  302  for guiding and stabilizing the driver  330   a  as it moves within its respective channel. The primary driver portion  340  further has a first forward support column  344  and a first rearward support column  346  protruding upward from the first driver base  342 . The first forward support column  344  has a first forward staple-receiving groove  345  therein and the first rearward support column  346  has a first rearwardly staple-receiving groove  347  therein. See  FIGS. 13-15 . The first forward support column  344  and the first rearward support column  346  are spaced from each other and collectively form a first staple cradle  348  for supporting the main portion  223  of the staple  222  therein in an upright position (i.e., prongs facing the anvil). Similarly, the secondary driver portion  350  has a secondary driver base  352  and a secondary forward support column  354  and a secondary rearward support column  356  protruding out from the second driver base  352 . The secondary forward support column  354  has a secondary forward staple-receiving groove  355  therein and the secondary rearward support column  356  has a secondary rearward staple-receiving groove  357  therein. The secondary forward support column  354  and the secondary rearward support column  356  are spaced from each other and collectively form a secondary staple cradle  358  for supporting the main portion  223  of another staple  222  therein. 
     As can be seen in  FIGS. 13 and 15 , the central base member  360  has an angled rearwardly facing edge  362  adapted to be engaged by a corresponding sled cam as will be discussed in further detail below. As can be seen in  FIGS. 13 and 14 , in this embodiment, the secondary forward support column  354  of the secondary driver portion is oriented relative to the first rearward support column  346  such that the staple  222  that is supported in the secondary staple cradle  358  is longitudinally offset from the staple  222  in the first staple cradle  348 . The reader will appreciate that the first inside drivers  330   a  are each installed in one orientation into a corresponding pair of channels  320   b  and  320   c  located on one side of the elongated slot  310  in the cartridge body  302 . The second inside staple drivers  330   b  (located on the opposite side of the elongated slot  310  from the first inside staple drivers  330   a ) comprise inside drivers  330   a  rotated 180 degrees so that their respective angled surfaces  363  face towards the proximal end  304  of the cartridge  300  to enable them to be installed in pairs of corresponding channels  320   d  and  320   e . Thus, in this embodiment, only one inside driver configuration is employed which thereby eliminates the need for two different inside staple driver configurations for channels on each side of the elongated slot  310 . 
       FIGS. 16 and 17  illustrate one embodiment of a “first” outside staple driver  370   a . As can be seen in those Figures, a first outside staple driver  370   a  has a second base  372  that has an angled rearwardly facing portion  374 . Protruding upward from the second base  372  is a second forward support column  375  that has a second forward staple-receiving groove  376  therein. A second rearward support column  377  also protrudes upward from the second base  372  in a spaced-apart relationship with respect to the second forward support column  375 . The second rearward support column  377  has a second rearward staple-receiving groove  378  therein. The support columns  375 ,  377  collectively form a second staple cradle  379  that is configured to support a staple  222  therein in an upright position as illustrated in  FIGS. 16 and 17 . The staple drivers  370   a  also have a laterally protruding rib  371  which is received in a corresponding groove (not shown) in the cartridge body  302  for guiding and stabilizing the driver  370   a  as it moves within its respective channel. 
     The reader will appreciate that a first outside driver  370   a  is installed in one orientation into a corresponding channel  320   a  on one side of the elongated slot  310 . A second outside staple driver  370   b  (to be located on the opposite side of the elongated slot  310  from the first outside staple drivers  370   a ) comprises an outside driver  370   a  rotated 180 degrees so that the angled surface  374 ′ thereon faces toward the proximal end  304  of the cartridge  300  to enable it to be installed in a corresponding channel  320   f  in the cartridge body  302 . Thus, in this embodiment, only one outside staple driver configuration is employed which avoids the need for two different outside staple driver configurations for channels on each side of the elongated slot  310 .  FIGS. 19 and 19A  illustrate in cross-section one embodiment of a staple cartridge of the present invention mounted within one type of end effector  12 . The end effector  12  in this embodiment employs a “stepped” anvil  18  of the type illustrated in  FIGS. 23-25 . In other embodiments, however, the bottom surface of the anvil is planar and not stepped. Other As can be seen in  FIGS. 19A, and 23-25 , the anvil  18  has a central portion  19  that is offset or not coplanar with the two lateral side portions  21 ,  23 . Accordingly, in this embodiment, the upper surface  306  of the cartridge  300  is provided with a recessed central portion  307  and two lateral side portions  309  that are adapted to closely mate with the corresponding portions  19 ,  21 ,  23 , respectively, of the anvil  18 , when the anvil  18  is in the closed position. See  FIG. 19A . 
     As can be seen in  FIG. 24 , in this embodiment, the under surfaces  200  of anvil  18  are provided with a series of forming pockets  202  that may be arranged in rows that correspond to the rows of channels in the cartridge  300 . That is, row  205  of pockets  202  may correspond to channel row  500 . Row  207  of pockets may correspond to channel row  502 . Row  209  of pockets  202  may correspond to channel row  504 . Row  211  of pockets  202  may correspond to channel row  506 . Row  213  of pockets  202  may correspond to channel row  508 . Row  215  of pockets  202  may correspond to channel row  510 . Each pocket  202  has at least one forming surface  203  therein that is adapted to contact the ends of the staple prongs  225  being driven therein to thereby cause the prongs  225  to bend inwardly toward each other. In one embodiment, each pocket  202  has two intersecting arcuate forming surfaces  203  that are oriented as shown in  FIG. 14A . Each arcuate forming surface has an apex  203 ′ that defines a maximum pocket depth “Z”. However other forming pocket configurations could be employed. 
     Returning to  FIGS. 18 and 19 , it can be seen that in one embodiment, the cartridge body  302  is mounted within the cartridge tray  224 . As illustrated in  FIG. 19 , the cartridge body  302  is formed with two inside longitudinally extending slots  390  and two outside longitudinally extending slots  392 . Slots  390  and  392  extend from the proximal end  304  of the cartridge to its tapered outer tip  306  (shown in  FIG. 10 ). This embodiment further includes a wedge sled  400  that slidably supported on the cartridge tray  224 . One wedge sled embodiment  400  includes a pair of inside sled cams  410 , wherein one inside sled cam  410  corresponds to one of the inside longitudinally extending slots  390  and wherein the other inside sled cam  410  corresponds to the other inside longitudinally extending slot  390 . See  FIG. 19 . The wedge sled  400  further includes a pair of outside sled cams  420 , wherein one outside sled cam  420  corresponds to one of the outside longitudinally extending slots  392  and the other outside sled cam  420  corresponds to the other outside longitudinally extending slot  392  as shown in  FIG. 19 . When assembled, the cartridge tray  224  holds the wedge sled  400  and the drivers  330   a ,  330   b ,  370   a ,  370   b  inside the cartridge body  302 . 
     As can be seen in  FIG. 18 , 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. 
       FIGS. 20-23  illustrate one embodiment of the wedge sled  400  of the present invention. As can be seen in  FIGS. 20 and 23 , the wedge sled  400  includes a central spacer portion  402  that extends between the inside sled cams  410 . A pusher block  404  is formed on the central spacer portion  402  for engagement with the middle pin  46  of the firing bar  14 . A side profile of one embodiment of an inside sled cam  410  is depicted in  FIG. 21 . As can be seen in that Figure, the inside sled cam  410  has a bottom surface  412 , and a first camming surface  414  that forms an angle “G” with the bottom surface  412  and a second camming surface  415  that extends to a top surface  416 . In one embodiment, for example, the angle “G” may be 35 degrees and the angle “G′” may be 20 degrees. The height of the inside sled cam  410  (the distance between the bottom surface  412  and the top surface  416 ) is represented as “first” sled cam height “H”. In one embodiment, distance “H’ is approximately 0.173 inches and the length of the top surface  416  may vary from embodiment to embodiment. As will be further evident as the present Detailed Description proceeds, the first sled cam height represents the vertical distance that the inside sled cams  410  will drive the corresponding inside drivers  330   a ,  330   b  toward the anvil  18  during operation. 
     The wedge sled  400  further comprises lateral spacer portions  406  that extend between the inside sled cams  410  and the outside sled cams  420  as shown in  FIGS. 20 and 23 . A side profile of one embodiment of an outside sled cam  420  is depicted in  FIG. 22 . In this embodiment, the outside sled cam  420  has a bottom surface  422  and a first camming surface  424  that forms an angle “I” with respect to the bottom surface  422  and a second camming surface  425  that to a top surface  426 . In one embodiment, angle “I” may be approximately 35 degrees and angle “I” may be approximately 20 degrees. The height of the outside sled cam  420  (the distance between the bottom surface  412  and the top surface  416 ) is represented as the “second” sled cam height “J”. In one embodiment, distance “J’ is approximately 0.163 inches. The second sled cam height represents the vertical distance that the outside sled cams  420  will drive the corresponding outside drivers  370   a ,  370   b  toward the anvil  18  during operation. The reader will understand that the above-recited dimensions are illustrative of one embodiment and may vary for other embodiments. 
     With particular reference to  FIG. 23 , a portion of the staple cartridge  300  is removed to expose portions of the elongate channel  16 , such as recesses  212 ,  214  and to expose some components of the staple cartridge  300  in their unfired position. In particular, the cartridge body  302  (shown in  FIG. 18 ) has been removed. The wedge sled  400  is shown at its proximal, unfired position with a pusher block  404  contacting the middle pin  46  (not shown in  FIG. 23 ) of the firing bar  14 . The wedge sled  400  is in longitudinal sliding contact upon the cartridge tray  224  and includes wedges sled cams  410 ,  420  that force upward the double drivers  330   a ,  330   b  and the single drivers  370   b ,  370   b  as the wedge sled  400  moves distally. Staples  222  (not shown in  FIG. 23 ) resting upon the drivers  330   a ,  330   b ,  370   a ,  370   b  are thus also forced upward into contact with the anvil forming pockets  202  in anvil  18  to form closed staples. Also depicted is the channel slot  45  in the elongate channel  16  that is aligned with the elongated slot  310  in the staple cartridge  300 . 
       FIG. 24  depicts the end effector  12 , which is in an open position by a retracted closure sleeve  32 , with a staple cartridge  300  installed in the elongate channel  16 . The firing bar  14  is at its proximal position, with the upper pin  38  aligned in a non-interfering 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  300 , thereby allowing removal of a spent cartridge and insertion of an unfired cartridge, which may be “snapfit” into the elongate channel  16 . Specifically, in this embodiment, extension features  316 ,  318  of the staple cartridge  300  engage recesses  212 ,  214 , respectively (shown in  FIG. 23 ) of the elongate channel  16 . 
       FIG. 25  depicts the end effector  12  of  FIG. 23  with all of the staple cartridge  300  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 is a pair of opposing tissue stops  244  which serve to prevent tissue from being positioned too far up into the end effector  12  during clamping.  FIG. 26  depicts the end effector  12  in a closed position with the firing bar  14  in an unfired position. The upper pin  38  is in the anvil pocket  40  and is 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  400  distally so that the sled cams  410 ,  420  contact and lift double drivers  330   a ,  330   b  and the single drivers  370   a ,  370   b , respectively, to drive them upwardly toward the anvil  18 . 
     As can be appreciated from reference to  FIGS. 14A, 15A and 19A , in one embodiment of the present invention, the distance between the bottom of the first staple-receiving grooves  345 ,  347  forming the first staple cradle  349  and the apex  203 ′ of forming surfaces  203  of the corresponding forming pocket  202  of anvil  18 , when the anvil  18  is in the closed position and when the inside driver  330   a ,  330   b  is supported on the cartridge tray  224 , is referred to herein as the first staple forming distance “A”. The distance between the bottom of the secondary staple-receiving grooves  345 ,  347  forming the secondary staple cradle  349  and the apex  203 ′ of the forming surface  203  of the corresponding forming pocket  202  in the anvil  18  when the anvil  18  is in the closed position and the inside driver  330   a ,  330   b  is supported on the cartridge tray  224  is referred to herein as the secondary staple forming distance “B”. In one embodiment, the first staple forming distance “A” and the secondary staple forming distance “B” are substantially equal to each other. In other embodiments, those distances “A” and “B” may differ from each other. 
     As illustrated in  FIGS. 16A and 19A  the distance between the bottom of the second staple-receiving grooves  376 ,  378  that form the second staple cradle  379  and the apex  203 ′ of the forming surface  203  of a corresponding forming pocket  202  in anvil  18  when the anvil  18  is in the closed position and the outside drivers  370   a ,  370   b  are supported on the cartridge channel  224 , is referred to herein as a “second” staple forming distance “C”. 
       FIGS. 27 and 28  illustrate the forming of staples supported on some of the first outside drivers  370   a . In  FIG. 27 , one of the outside sled cams  420  of the wedge sled  400  is initially contacting one of the outside drivers  370   a . As the wedge sled  400  continues in the driving direction represented by arrow “K” in  FIG. 28 , the outside sled cam  420  causes the outside drivers  370   a  drive the staples  222  supported thereby into the staple forming pockets  202  in the anvil  18 . Likewise, as the wedge sled  400  is driven in the driving direction “K”, the inside sled cams  410  contact the inside drivers  330   a ,  330   b  and causes them to drive the staples  222  supported thereby into the corresponding staple forming pockets  202  in the anvil  18 . 
     As indicated above, in some applications involving an area of varied tissue composition, it can be desirable to form rows of staples wherein the formed (final) heights of the staples in a row that is the farthest distance away from the cut line are greater than the formed (final) heights of those staples in the row that is closest to the cut line. In other applications, it may be desirable for the formed heights of the staples in a single row to increase (or decrease) from staple to staple. Another clinical benefit would be to have the formed heights of the staples in the outermost rows larger than formed heights of the staples in the inside rows. The various embodiments of the subject invention can provide these results while employing identical staples in all of the rows. 
     In the description to follow, those staples  222  in the outermost rows  520 ,  530  of staples (those staples formed using the outside staple drivers  370   a ,  370   b ) will be referred to hereinafter as staples  222 ′ and those staples in the innermost rows  522 ,  524 ,  526 ,  528  of staples (those staples formed using the inside staple drivers  330   a ,  330   b ) will be referred to hereinafter as staples  222 ″. It will be understood, however, that staples  222 ′ and  222 ″ are identical to each other prior to being formed by the various embodiments of the present invention. That is, staples  222 ′ and  222 ″ each have identical prong lengths “P” and widths “W”. Returning to  FIGS. 14A-16A and 21 and 22 , the above desired effects may be attained by altering the staple forming distances “A”, “B”, and “C” relative to each other and/or the sled cam heights “H” and “J”. In one embodiment of the subject invention, for example, the height “H” of each of the inside sled cams  410  is substantially equal to the sled height “J” of each of the outside sled cams  420 . See  FIGS. 21 and 22 . In this embodiment, the staple forming distances “A” and “B” are substantially equal to each other, but distances “A” and “B” are less than the staple forming distance “C”. The distance “D” between the bottoms of the first staple-receiving grooves  345 ,  347  and the bottom surface  342 ′ of the primary driver base  342  is substantially equal to the distance “E” between the bottoms of the secondary staple-receiving grooves  356 ,  357  and the bottom surface  352 ′ of the secondary driver base portion  352 . See  FIG. 15 . Also in this embodiment, the distance “F” between the bottoms of the second staple-receiving grooves  376  and  378  and the bottom surface  373  of the third base  372  of the outside drivers  370   a ,  370   b  ( FIG. 16 ) is less than distances “D” and “E” ( FIG. 15 ). Because the forming distance “C” is greater than the forming distances “A” and “B”, the staples  222  supported and formed by the outside drivers  370   a ,  370   b  are not compressed as much as the staples supported and formed by the inside drivers  330   a ,  330   b . It will be understood that similar results may be attained on the opposite side of the elongated slot  310  and the cut line  600  formed in the tissue by using the same arrangements and sizes of inside drivers  330   b  and outside drivers  370   b . In an alternative embodiment, the same effect may be achieved by altering the depths of the forming pockets  202  corresponding to the drivers  330   a  and  370   b  such that forming distance “C” is greater than the forming distances “A” and “B”. That is, the depth (distance “Z′” in  FIG. 16A ) of the forming pockets  202  corresponding to the outside drivers  370   a .  370   b  may be greater than the depth (distance “Z” in  FIG. 14A ) of the forming pockets  202  that correspond to the inside drivers  330   a ,  330   b.    
       FIG. 29  illustrates the rows of staples formed on each side of a cut line  600  utilizing this embodiment of the present invention wherein the forming distances “A” and “B” are equal to each other and the forming distance “C” is greater than the forming distances “A” and “B”. For example, if forming distance “C” is 0.020″ greater than forming distances “A” and “B”, the formed height of the outside staples  222 ′ (represented as dimension “L” in  FIG. 30 ) in rows  520  and  530  would be 0.020 inches is greater than the formed height of the inside staples  222 ″ (represented as dimension “M” in  FIG. 31 ) in rows  522 ,  524 ,  526 ,  528 . 
     The same result may be achieved by utilizing another embodiment of the present invention wherein the forming distances “A”, “B” and “C” are essentially equal. In this embodiment, however, the height of each of the inside sled cams  410  (distance “H” in  FIG. 21 ) is greater than the height of each of the outside sled cams  420  (distance “J” in  FIG. 22 ). Thus, because the height “H” of the inside sled cams  410  is greater than the height “J′” of the outside sled cams  420 , the inside sled cams  410  will drive the corresponding inside drivers  330   a ,  330   b  further towards the anvil than the outside sled cams  420  will drive the corresponding outside drivers  370   a ,  370   b . Such driving action will cause the staples supported by the inside drivers  330   a ,  330   b  to be compressed to a greater extent than those staples supported by the outside drivers  370   a ,  370   b . For example, if distance “H” is 0.020 inches greater than distance “J”, the formed height of staples  222 ′ in lines  520 ,  530  would be 0.020″ greater than the formed height of staples  222 ″ in lines  522 ,  524 ,  526 ,  528 . 
     When employing yet another embodiment of the present invention, the outside rows  520 ,  530  of staples  222 ′ and the inside rows  522 ,  528  of staples  222 ″ may be formed with heights that are greater than the formed heights of the staples  222 ″ in the inside rows  524 ,  526 . See  FIG. 32 . This result is achieved by making the forming distances “C” greater than the forming distance “A” and making forming distance “A” greater than secondary forming distance “B”. 
     Another embodiment of the present invention can be used to install staples where it is desirable for the formed heights of staples in a single row to vary. One such arrangement is depicted in  FIG. 33 . As can be seen in  FIG. 33 , the formed heights of the staples  222 ′ in the outside rows  520 ,  530  increase when moving from the proximal ends  521 ,  531  of each row  520 ,  530 , respectively to the distal ends  523 ,  533  of each row  520 ,  530 , respectively. This effect may be accomplished by decreasing the forming distance “C” for each succeeding driver  370   a ,  370   b . That is, the driver  370   a  closest the proximal end of the cartridge  300  would be sized to establish a forming distance “C” that is greater than the forming distance “C” achieved by the adjacent driver  370   a  and so on to achieve a condition wherein each succeeding staple  222 ′ (moving in the direction from the proximal end to the distal end of the cartridge  300 ) would have larger formed heights. This result could also be attained in the staples  222 ″ in rows  522 ,  524 ,  526 ,  528  by similarly altering the forming distances “A” and/or “B” attained by each driver  330   a ,  330   b . Likewise, formed heights of the staples  222 ′ in the outside rows  520 ,  530  could be made to decrease when moving from the proximal ends  521 ,  531  of each row  520 ,  530 , respectively, to the distal ends  523 ,  533  of each row  520 ,  530 , respectively. This result may be attained by increasing the forming distance of each succeeding driver  370   a ,  370   b . That is, the driver  370   a  closest the proximal end of the cartridge  300  would have a forming distance “C” that is less than the forming distance “C” of the adjacent driver  370   a  and so on to achieve a condition wherein each succeeding staple  222 ′ (moving in the direction from the proximal end to the distal end of the cartridge) would have smaller formed heights. See  FIG. 34 . 
     In use, the surgical stapling and severing instrument  10  is used as depicted in  FIGS. 1-2 and 35-41 . In  FIGS. 1-2 , the instrument  10  is in its start position, having had an unfired, fully loaded staple cartridge  300  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  300  and the anvil  18 , as depicted in  FIG. 35 . With reference to  FIGS. 36 and 37 , the clinician then 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 refracted 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. 38 and 39 , 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  300  through the firing drive slot  47  to affect the firing of the staples  222  (not shown in  FIGS. 38 and 39 ) via wedge sled  400  toward the anvil  18 . The lowermost 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. 40 and 41 , 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 . 
       FIGS. 42-43  show the inside and outside sled cams  410 ,  420  of the sled  400  having different heights so that the staples, when formed, may have different formed heights. In particular, as shown in  FIG. 42  the outside sled cam  420  may be shorter than the inside sled cam  410 . That way, the outside staples may have a greater formed height than the inside staples.  FIG. 42  is a perspective view of the sled  400  with the different heights for the inside and outside sled cams  410 ,  420 .  FIG. 43  is a side view of the end effector  12  showing various stages of driving the staples  222  with a sled  400  having different heights for the inside and outside sled cams  410 ,  420 . As can be seen in  FIG. 43 , the formed staple  222   b  may have a greater formed height than the formed staple  222   a  because the staple  222   b  was driven by the outside cam sled  420  and the staple  222   a  was driven by the taller inside cam sled  410 . 
     In another embodiment, as shown in  FIG. 44 , the heights of the driver portions  342 ,  352  of a double driver  330  may vary so that the staples, when formed, may have different heights. In particular, as shown in  FIG. 44 , the secondary driver portion  352  may be shorter (having height “E”) than the primary driver portion  342  (having height “D”). That way, the staple  222   a  driven by the secondary driver portion  352  may have a greater formed height than the staple  222   b  driven by the primary driver portion  342 . In various embodiments, some or all of the inside double drivers  330  could have primary and secondary driver portions  342  of different heights. Further, the heights differential need not be all the same. Different inside double drivers  330  could have different height differentials. 
     In addition, the height of the primary and secondary driver portions  342 ,  352  may be the same as or different from the height of the driver portions  372  of the outside staple drivers  370 . That is, in various embodiments, the driver height of the outside staple driver portion  372  may be (1) different from the height of both driver portions  342 ,  352  of the inside double driver  330  when the driver portions  342 ,  352  are the same height, (2) different from the height of both driver portions  342 ,  352  when they are different heights, or (3) the same as the height for one of the driver portions  342 ,  352  when the driver portions  342 ,  352  have different heights. Also, the heights of the driver portions  372  of the outside staple drivers  370  need not be all the same. Different outside staple drivers  370  could have different heights. 
       FIG. 45  shows an embodiment having different height drivers (e.g., the primary driver portion  342  taller than the secondary driver portion  352 ) and with different depth anvil pockets  202 . Varying the depth of the anvil pockets  202  can also affect the height of the formed staples. All things being equal, deeper pockets should result in longer formed staples. In the illustrated embodiment, the pockets  202  corresponding to the primary driver portion  342  are deeper than the pockets  202  corresponding to the secondary driver portion  352 . Some or all of the pockets  202  for each staple row  500 - 510  could be deeper. Also, the depth differentials need not be the same. A multitude of different depths could be used in a single row  500 - 510  or across rows  500 - 510 . 
     In addition, as shown in  FIG. 46 , staples  222  with differing pre-formation prong heights (“P”) may be used. In the illustrated embodiment, the longer staple  222   a  is used with the shorter, secondary driver portion  352  of an inside double driver  330  in comparison with staple  222   b  driven by the primary driver portion  342 . The pre-formation staple prong lengths may vary within a staple row  500 - 510  or across staple rows. That is, for example, all of the staples in the inside rows  504 - 506  could have the same pre-formation prong length x, all of the staples in the intermediate rows  502 ,  508  could be longer (e.g., a length 1.10x), and all of the staples in the outer rows  500 ,  510  could be still longer (e.g., a length of 1.20x). As shown in  FIG. 47 , the anvil pockets  202  could have the same depth. In other embodiments, varying anvil pocket depths could be used. 
       FIG. 48  is a side view of the end effector  12  in an embodiment where the outside staple drivers  370  have different heights. In particular, in the illustrated embodiment, the first staple driver  370 ′ is taller than the second staple driver  370 ″. In the illustrated embodiment, the staples  222  have the same pre-formation prong length and the corresponding anvil pockets  202  have the same depth. As such, the formed staple  222 ″ formed with the second outside staple driver  370 ″ is longer than the formed staple  222 ′ formed with the first outside staple driver  370 ′. 
       FIG. 49  is a side view of the end effector  12  where the anvil  18  has pockets  202  of different depth for the staples  222  driven by a inside double driver  330 . In the illustrated embodiment, the pockets  202  corresponding to the primary driver portion  342  are deeper than the corresponding pockets  202  for the secondary driver portion  352 . In this embodiment, the primary and secondary driver portions  342 ,  352  are the same height and the staples  222  have the same pre-formation prong length. The distance between the top of the primary driver portion  342  and the top of the corresponding anvil pockets  202  is height “A” and the corresponding height for the secondary portion  352  is height “B,” where “A” is greater than “B” by a height differential “h”. This should result in longer formed staples for the primary driver portion  342 , as shown in  FIG. 50 . 
       FIGS. 51 and 60  show aspects of an end effector  12  according to other embodiments that can be used to produce staples of different formed lengths. In the illustrated embodiment, the staple drivers  330 ,  370  are driven in stages by a plurality of actuator wedge cams  709  at the distal end of a plurality of wedge band sets  710 ,  712 ,  714 . In the illustrated embodiment, each wedge band set comprise four wedge bands (shown best in  FIG. 56 ); two  720  for actuating the inner drivers  330   a,b  and two  722  for actuating the outer drivers  370   a,b . The wedge bands of the wedge band sets  710 ,  712 ,  714  may be actuated in serial order and may ride on top of one another in a stack to drive the staple drivers  330   a,b ,  370   a,b  (and hence the staples  222 ) in serial stages. For example, the wedge bands of the lowermost actuator wedge band set  710  may be fired (or actuated) first, and may partially deploy the staples  222 . The middle wedge band set  712 , which rides on top of the lowermost wedge band set  710  as shown in  FIGS. 53-56 , may be actuated next, which may have the effect of beginning to form the staples  222 . Then the uppermost wedge band set  714 , which rides on the middle wedge band set  712 , may be actuated, which finishes the formation of the staples  222 .  FIG. 56  illustrates this operation. In  FIG. 56 , the lowermost wedge band sets  710  have been fired, the middle wedge band sets  712  have been partially fired, and the uppermost wedge band set  714  has not yet been fired. Thus, such an embodiment may comprise a plurality (in this case four) of stacked wedge band sets, each stack comprising a wedge band from the lowermost set  710 , the middle set  712 , and the uppermost set  714 . 
     The firing bar  716 , with the e-beam firing mechanism  14 , may then be fired to cut the tissue clamped by the end effector  12 . A hold down spring  718 , which may be connected to the frame  34  at a crossbar  719 , may engage and urge the firing bar  716  downward. 
     As can be seen best in  FIGS. 54 and 56 , the cumulative height of the wedge band stacks of inner row  720  or may be greater than the cumulative height of the wedge band stacks of the outer row  722  (by a height differential h′). That way, the outer row of staples may have a greater formed length than the inner row of formed staples, as shown in the example of  FIG. 55 , where the outer row staple  222   a  has a greater formed length than the inner row staple  222   b . As shown the example of  FIG. 61 , according to one embodiment, the wedge bands of the lowermost and middle wedge bands sets  710 ,  712  may be the same height, and the height of the wedge bands for the outer row  722  of the uppermost wedge band set  714  may be less than the height of the wedge bands of the inner row  720  of the uppermost wedge band set  714  to provide the height differential for the different wedge band stacks. 
     The end effector  12  in such an embodiment may still comprise a sled  400 , but without the sled cams  410 ,  420 , to keep the firing mechanism  14  out of the lockout in the channel (see  FIGS. 3-4  and related text). 
     The inner and outer wedge band stacks  720 ,  722  may be tightly spaced within the frame  34 . Accordingly, the end effector  12  may further comprise an actuator wedge band respective guide  702  for spreading out the wedge band stacks  720 ,  722  when they enter the end effector  12  to align with the staple drivers  330 ,  370 . The wedge band guide  702  may include wedge band channels for each of the inner and outer wedge band stacks  720 ,  722 . That is, in the illustrated embodiment, the wedge band guide  702  may comprise four wedge band channels—two of the inner rows  720  and two for the outer rows  722 .  FIGS. 58-60  show one side of the wedge band guide  702  in more detail. As shown in  FIG. 60 , the wedge band channels  730 ,  732  may force the wedge band stacks  720 ,  722  outward as they enter the end effector  12 . The inner wedge band channel  730  may direct the inner wedge band stack  720  so that the inner wedge band stack  720  aligns with the inner staple drivers  330  and the outer wedge band channel  732  may direct the outer row wedge band stack  722  so that the outer wedge band stack aligns with the outer staple drivers  370 . In the illustrated embodiment, the channels  730 ,  732  are straight. In other embodiments, one or both of the channels  730 ,  732  may comprise curved portions. 
       FIG. 62  is a cross-sectional view of the shaft assembly  10  according to such an embodiment. As shown in  FIG. 62 , each wedge band set  710 - 714  may have its own actuation (or firing) bar. The lowermost actuation bar  740  may actuate the wedge bands of the lowermost wedge band set  710 , the middle actuation bar  742  may actuate the wedge bands of the middle wedge band set  712 , and the uppermost actuation bar  744  may actuate the wedge bands of the uppermost wedge band set  714 . The firing bar  716  for actuating the cutting instrument  14  may be connected to the uppermost wedge band set  714  so that the cutting instrument  14  is actuated with the uppermost (last) wedge band set  714 . In other embodiments, the firing bar  716  may have its own actuation mechanism so that is may be actuated separately. 
     In practice, the clinician may choose (or select) to actuate less than all of the wedge band sets  710 - 714  before actuating the firing rod  716  to cut the tissue to thereby exercise some choice in the length of the staples to be formed. For example, in various embodiments, the clinician may select to actuate the lowermost and middle wedge band sets  710 ,  712 —and not the uppermost wedge band set  714 —before cutting. 
       FIGS. 63-69  illustrate an embodiment of an open linear stapling and cutting device  800  that may use multiple stacked wedge band sets to produce staples of different formed lengths. In the illustrated embodiment, the anvil  810  is below the channel  809 . As such, the staples are driven down through tissue clamped in the end effector  12  as part of the stapling operation. 
     The device  800  may include an upper body piece  802  and a lower body piece  804 . The upper body piece  802  may include a channel  806  in which the staple cartridge  809  is inserted. The anvil  810  may be connected to the lower body piece  804  and face the staple cartridge  809  so that the staples  222  can be formed against the staple forming surface  812  of the anvil  810 . When the clinician is satisfied with the position of the tissue between the cartridge  809  and the anvil  810 , the clinician may lock the device  800  using a clamp lever  814  of a clamp lever assembly  816  connected to the upper body piece  802 . 
     The staple drivers  820  in the cartridge  809  may be actuated in stages using multiple staged wedge band stacks. Because the staples  222  are driven down in this embodiment, the wedge bands of the uppermost wedge band set  822  may be actuated first to partially deploy the staples  222 . Next, the wedge bands of the middle wedge band set  824 , which ride on the uppermost wedge band set  822 , may be actuated to begin forming the staples  222 . Then the wedge bands of the lowermost wedge band set  826 , which ride on the middle wedge band set  824 , may be actuated, which finishes the formation of the staples  222 . 
     In the illustrated embodiment, the firing bar  828 , with the knife  830  at is distal end, is connected to the lowermost wedge band set  826  and is fired with the lowermost wedge band set  826 . A hold down spring  832  may engage and urge the firing bar  828  upward. A knife retainer  834  may retain the firing bar  828  with the lowermost wedge band set  826 . 
     As best shown in  FIGS. 67-68 , the clinician may actuate the wedge band sets using a three-part actuation slide bar  840 . The upper piece  842  may actuate the uppermost (initial) wedge band set  822 . The middle piece  844  may actuate the middle wedge band set  824 . The lower piece  846  may actuate the lowermost (last) wedge band set  826 . 
     To form staples of different formed heights, the staple pushers  820  may have different heights. For example, as shown in  FIG. 66 , one set of staple pusher  820   a  could be shorter than another set of staple pushers  820   b . As such, the formed staple  222   a , produced by the shorter staple pusher  820   a , may have a longer formed length than the formed staple  222   b , formed by the longer staple pusher  820   b . In other embodiments, the staples  222  may have different lengths or wire diameters to create different length formed staples, and/or the pockets  202  in the anvil  810  could have different depths to create different length formed staples. Also, the cumulative heights of the wedge band stacks could be different. 
     According to various embodiments of the present invention, the staple drivers could have a staple/driver interface that permits staples of varying wire diameter to be employed. For example, as shown in the embodiments of  FIGS. 78-83 , the outside staple drivers  370   a,b  may have a raised dimple configuration on its upper surface for supporting staples having differing wire diameters. The dimple configuration may comprise, as shown in the illustrated embodiment, two inner sets of outwardly protruding dimples (or convex bumps)  620   a,b , and two outer sets of dimples  622   a,b . Each set of dimples defines a receiving area where a staple  222  may sit in the upright position, as shown in  FIGS. 81-83 . The dimples of the inner sets  620   a,b  may be larger than the dimples of the outer dimple sets  622   a,b  so that the receiving area of the inner sets  620   a,b  is less than for the outer dimple sets  622   a,b . Nevertheless, due to the convex nature of the dimples, staples  222  of varying wire thicknesses may be accommodated, as shown in  FIGS. 82 and 83 . For example, the dimples could be configured so that the staple drivers  370  can accommodate staples having a wire diameter of 0.006 inches to 0.012 inches, or some other range such as 0.004 inches to 0.008 inches or 0.006 inches to 0.008 inches, etc. As such, staples of different wire thicknesses could be used in a single cartridge  306 . Differing wire diameters would produce different formed staple heights all other things being equal (e.g., same drive/crush distance, same pocket depth, etc.). In addition, as shown best in  FIG. 78 , the staple cradles for the inside drivers  330  may include sharp points  624  that may injure the tissue that is being stapled. The dimple configurations on the outside staple drivers  370  lack such sharp points, which would tend to minimize the trauma on the tissue being stapled. 
     In the illustrated embodiment, the outer staple drivers  370   a,b  have the raised dimple configuration in order to accommodate staples of different wire diameters and the staple cradles of the inside staple drivers  342 ,  352  can only support upright staples of one general wire diameter. In other embodiments, the one or both of the inside staple drivers  342 ,  352  may also or alternatively have the raised dimple configuration. Also, rather than using the raised dimple configuration, a v-shaped staple channel  349 ,  379  may be used. Such a v-shaped channel may also accommodate staples having different wire diameters. Also, staple pushers with staple interfaces that accommodate different staple wire diameters could be used with other types of staple drivers than the inside double and outside single staple drivers shown in  FIGS. 78-83 . 
       FIGS. 70-77  are cross-sectional frontal views of the end effector  12  according to various embodiments of the present invention. In the embodiment shown in  FIG. 70 , the anvil  18  is stepped, having a central portion  19  that is offset relative to (or not coplanar with) the two lateral side portions  21 ,  23 . Also, the upper surface  306  of the cartridge  300  has a recessed central portion  307  and two lateral side portions  309  (see  FIG. 19A ). All the staples  222  have the same pre-formation prong height and the corresponding anvil pockets  202  have the same depth. However, due to the stepped nature of the anvil  18 , the pockets  202  on the two lateral side portions  21 ,  23  of the anvil  18  are offset from the pockets in the central portion  19  of the anvil. Offsetting the vertical position of the staple forming pockets  202  can affect the length of the formed staples  222 . All other things being equal, staples formed by staple forming pockets that are elevated will have a longer formed length than staples formed with pockets that are not elevated. Also in this embodiment, the primary and secondary driver portions  342 ,  352  of the double inside drivers  330   a,b  are the same height, and the height of the driver portion  372  of the outside staple drivers  370   a,b  is greater than the height of the driver portions  342 ,  352  of the double inside staple drivers  330   a,b . Also, the inside and outside sled cams  410 ,  4120  are the same height in this embodiment. 
       FIG. 71  shows an embodiment where the end effector  12  has a stepped cartridge tray  224  at the bottom of the cartridge  300  to match the steps in the channel  16 . In particular, in the illustrated embodiment, the cartridge tray  224  has a central portion  602  on which the double inside staple drivers  330   a,b  rest and outer lateral portions  604  on which the outside staple drivers  370   a,b  rest. As can be seen in  FIG. 71 , the central portion  602  of the cartridge tray  224  is elevated above the lateral portions  604 . As such, the sled  400  may be configured so that the outside sled cam  420  is positioned lower than the inside sled cam  410  so that the outside sled cam  420  can engage the lower outside driver portions  370   a,b.    
     The embodiment illustrated in  FIG. 72  is similar to that shown in  FIG. 71  except that in  FIG. 72  the cartridge  300  does not include the cartridge tray  224 . Rather, the staple drivers  330 ,  370  rest directly on the channel  16 . Such an embodiment may be beneficial because it may allow for more material (e.g., metal) in the channel  16  at points A and B than in a similar embodiment with the cartridge tray  224  (such as shown in  FIG. 71 ). 
     The embodiment illustrated in  FIG. 73  is also similar to that shown in  FIG. 71  except that in  FIG. 73  the cartridge tray  224  is raised slightly relative to the bottom on the channel  16  in comparison with the embodiment shown in  FIG. 71 . Such an embodiment may also allow for more material (e.g., metal) in the channel  16  at points A and B than in the embodiment shown in  FIG. 71 . According to other embodiments, the height of the anvil  18  could be reduced to permit more material in the channel  16  at points A and B. 
     The embodiment of  FIG. 74  is similar to that used in  FIG. 73  except that no cartridge tray  224  is included in the embodiment of  FIG. 74 . 
     The embodiment of  FIG. 75  is similar to that of  FIG. 70  except than in  FIG. 75  the outer rows of pockets  202  are formed in a compliant material portion  610  of the anvil  18 . The compliant material portion  610  may be made from a material that is more compliant to the rest of the anvil  18 . For example, the compliant material portion  610  may be made from plastic or a plastic composite material and the rest of the pockets may be defined in a less-compliant material, such as stainless steel, of the anvil  18 . The less-compliant anvil portion is sometimes referred to herein as “non-compliant” to distinguish it from the compliant materials portion  610 , although it should be recognized that the so-called non-compliant material portion would be somewhat compliant, just less compliant than the compliant material portion  610 . All things being equal, staples formed with the outer pockets  202  formed in the compliant material portion  610  of the anvil  18  would be longer than stapled form in the non-compliant (e.g., metal) portion of the anvil  18  because the compliant material portion  610  would compress more during the staple formation process. 
       FIGS. 76 and 77  collectively show another embodiment. In this embodiment, the channel  16  includes a compliant material portion  612  under the outside drivers  370 . The complaint material portion  612  may be plastic or a composite plastic, for example. The inside drivers  330  may rest on the less-compliant (or “non-compliant”) channel  16 , which may be made of metal (e.g., stainless steel). The outside sled cam  420  may slightly compress the compliant material portions  612  under the outside drivers  370  when forming the staples in relation to the inside drivers  330  on the channel  16 , thereby forming slightly longer staples in the outside rows. In other embodiments, the compliant material portions  612  could be under the inside drivers  330  if it was desired to make the inside staples have a greater formed length. 
     According to other embodiments, staples of different materials could be used to produce staples of different formed lengths. The different materials may have different modulus of elasticity so that they will be formed differently given the same driving force. Staples having a higher modulus of elasticity will tend to be deformed less given the same driving force, thereby tending to produce staples having a longer formed length. The different materials for the staples  222  may comprise titanium, stainless steel, alloys, etc. 
     The present invention is also directed to other types of surgical cutting devices that can create formed staples of different heights. For example,  FIGS. 84-89  illustrate a circular stapler  900  that is capable of forming staples with different formed heights. As seen in  FIG. 84 , the circular stapler  900  includes a head  902 , an anvil  904 , an adjustment knob assembly  906 , and a trigger  908 . The head  902  is coupled to a handle assembly  910  by an arcuate shaft assembly  912 . The trigger  908  is pivotally supported by the handle assembly  910  and acts to operate the stapler  900  when a safety mechanism (not shown) is released. When the trigger  908  is activated, a firing mechanism (not shown in  FIG. 84 ) operates within the shaft assembly  912  so that staples  914  are expelled from the head  902  into forming contact with the anvil  904 . Simultaneously, a knife  916  operably supported within the head  902  acts to cut tissue clamped between the head  902  and the anvil  904 . The stapler  900  is then pulled through the tissue leaving stapled tissue in its place. 
       FIGS. 85 and 86  illustrate one form of the anvil  904  and the head  902  that may be employed in connection with various embodiments of the subject invention. As can be seen in these figures, the anvil  904  may have a circular body portion  920  that has an anvil shaft  922  for attaching a trocar (not shown) thereto. The anvil body  920  has a staple forming surface  924  thereon and may also have a shroud  926  attached to the distal end thereof. The anvil  904  may be further provided with a pair of trocar retaining clips or leaf-type springs  928  that serve to releasably retain the trocar in retaining engagement with the anvil shaft  922 . A plastic knife board  930  may be fitted into a cavity  932  in the anvil body  904 . 
     The head  902  may comprise a casing member  940  that supports a cartridge supporting assembly in the form of a circular staple driver assembly  942  therein that is adapted to interface with a circular staple cartridge  944  and drive the staples  914  supported therein into forming contact with the staple forming surface  924  of the anvil  904 . The circular knife member  916  is also centrally disposed within the staple driver assembly  942 . The proximal end of the casing member  940  may be coupled to an outer tubular shroud  946  of the arcuate shaft assembly  912  by a distal ferrule member  948 . More details regarding circular staples may be found in U.S. patent application Ser. No. 11/541,151, entitled SURGICAL CUTTING AND STAPLING DEVICE WITH CLOSURE APPARATUS FOR LIMITING MAXIMUM TISSUE COMPRESSION FORCE, filed Sep. 29, 2006, now U.S. Pat. No. 7,665,647, which is incorporated herein by reference. 
     As can be seen in  FIGS. 85-89 , the staple driver assembly  942  may comprise an outer ring of staple drivers  950  and an inner ring of staple drivers  952 . Correspondingly, the anvil  904  may comprise two concentric rings of staple forming pockets  202 . Actuation of the firing trigger  908  of the handle assembly  910  cause a compression shaft (not shown) of the shaft assembly  912  to move distally thereby driving the staple driver assembly  942  distally to fire the staples  914  into forming contact with the staple forming surface  924  of the anvil  904 . Thus, the outer staple drivers  950 , when actuated by the drive mechanism of the stapler  900 , drive an outer ring of staples  914  into the clamped tissue and are formed by surface forming surface  924  of the anvil  904 . Similarly, the inner staple drivers  952 , when actuated by the drive mechanism of the stapler  900 , drive an outer ring of staples  914  into the clamped tissue and are formed by surface forming surface  924  of the anvil  904 . 
     The staple drivers  950 ,  952  could be of different heights to thereby form different length formed staples (all other things being equal). For example, as shown in the illustrated embodiment, the outer staple drivers  950  may be shorter than the inner staple drivers  952  so that the outer formed staples are longer than the inner formed staples, as shown in  FIG. 88 . Of course, in other embodiments, the inner staple drivers  952  could be shorter than the outer staple drivers  950 . Further, the outer staple drivers  950  may not be a uniform height; there could be height variation among the outer staple drivers  950 . Similarly, there could be height variation among the inner staple drivers  952 . 
     In addition, staples with different pre-formation prong heights could be used. Also, the staple forming pockets  202  in the surface forming surface  924  of the anvil  904  may have varying depths to thereby vary the length of the formed staples. Also, as described above, some or all of the staple drivers  950 ,  952  may have a dimple configuration at their interface with the staples  914  to accommodate staples of different wire diameters or some other configuration that accommodates staples of different wire diameters (e.g., a v-shaped staple channel). Also, some of the pockets  202  in the anvil  1006  may be formed in a compliant material portion of the anvil  1006 . Also, the staples  914  could be made of materials that have a different modulus of elasticity. 
     In other embodiments, as shown in  FIGS. 90-95 , the present invention is directed to a linear stapler  1000  that is capable of forming staples of different heights.  FIGS. 90-95  focus on the end effector  1002  for such a linear stapler  1000 . The end effector  1002  may comprise a replaceable staple cartridge  1004  and a linear anvil  1006 . The cartridge  1004  comprises staples which are driven into and formed by the anvil  1006  when the device  1000  is actuated. Unlike the endocutters described before, the anvil  1006  may be non-rotatable in the linear stapler  1000 . To clamp tissue in the end effector  1002 , the user may squeeze a clamping trigger (not shown), which causes the cartridge  1004  to slide distally toward the anvil  1006  from an open position to a closed position. More details regarding the operation and components of a liner stapler may be found in U.S. Pat. No. 5,697,543, entitled LINEAR STAPLER WITH IMPROVED FIRING STROKE, by M. Burdorff (“the &#39;543 patent”), which is incorporated herein by reference. Typically, such linear staplers do not comprise a cutting instrument. 
       FIGS. 92-93  show the end effector  1002  with the outer cover of the cartridge  1004  removed. As can be seen in these figures, the staple cartridge  1004  may comprise a staple driver assembly  1010  comprising a row of inner staple drivers  1012  and a row of outer staple drivers  1014 . The staple drivers  1012 ,  1014  could be of different heights to thereby form different length formed staples (all other things being equal). For example, as shown in the illustrated embodiment, the outer staple drivers  1014  may be shorter than the inner staple drivers  1012  so that the outer formed staples  222   b  are longer than the inner formed staples  222   a , as shown in  FIGS. 94-95 . Of course, in other embodiments, the inner staple drivers  1012  could be shorter than the outer staple drivers  1014 . Further, the outer staple drivers  1014  may not be a uniform height; there could be height variation among the outer staple drivers  1014 . Similarly, there could be height variation among the inner staple drivers  1012 . Also, the cartridge  1004  may comprise, for example, three rows of staples, where the outer two rows have shorter staple drivers and the inner row has longer staple drivers. 
     In addition, staples  1008  having different pre-formation prong heights could be used. Also, the staple forming pockets  202  in the surface forming surface  1016  of the anvil  1006  may have varying depths to thereby vary the length of the formed staples. Also, as described above, some or all of the staple drivers  1012 ,  1014  may have a dimple configuration at their interface with the staples  1008  to accommodate staples of different wire diameters or some other configuration that accommodates staples of different wire diameters (e.g., a v-shaped staple channel). Also, some of the pockets  202  in the anvil  1006  may be formed in a compliant material portion of the anvil  1006 . Also, staples  1008  of different materials could be used. 
     In operation, as described in more detail in the &#39;543 patent, when the clamping trigger is retracted by the user, the anvil  1006  is cause to slide proximally toward the staple cartridge  1004  into the closed position to clamp tissue in the end effector  102 . The cartridge  1004  may comprise a distally-extending tissue retaining pin  1020  that engages an opening  1022  in the anvil when the end effector  1002  is in the closed position to retain the tissue between the cartridge  1004  and the anvil  1002 . When the clinician retracts the separate firing trigger (not shown), a distally extending firing bar (not shown) is actuated, which actuates the staple drivers  1010  to drive the staples  1008 . 
     In another embodiment, the linear stapler  1000  could be configured so that the staple cartridge  1004  slides distally toward the anvil when the clamping trigger is actuated. 
     It should be recognized that stapling devices according to the present invention may combine some of the features described herein for creating staples of different formed lengths. For example, for embodiments having different staple crushing distances, the staples may all have the same pre-formation prong length or some staples may have different pre-formation prong lengths. Also, the staples may all be made out of the same material, or staples made of different materials, with different modulus of elasticity, could be used. Also, the staple wire diameters may all be the same or some of them could be different. 
     The devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the device can be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the device can be disassembled, and any number of the particular pieces or parts of the device can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the device can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application. 
     Preferably, the various embodiments of the invention described herein will be processed before surgery. First, a new or used instrument is obtained and if necessary cleaned. The instrument can then be sterilized. In one sterilization technique, the instrument is placed in a closed and sealed container, such as a plastic or TYVEK bag. The container and instrument are then placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation kills bacteria on the instrument and in the container. The sterilized instrument can then be stored in the sterile container. The sealed container keeps the instrument sterile until it is opened in the medical facility. 
     It is preferred that the device is sterilized. This can be done by any number of ways known to those skilled in the art including beta or gamma radiation, ethylene oxide, steam. 
     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. The various embodiments of the present invention represent vast improvements over prior staple methods that require the use of different sizes of staples in a single cartridge to achieve staples that have differing formed (final) heights. 
     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. Moreover, the unique and novel aspects of the various staple cartridge embodiments of the present invention may find utility when used in connection with other forms of stapling apparatuses without departing from the spirit and scope of the present invention.