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United States Patent Application 20160256167
Kind Code A1
Kostrzewski; Stanislaw ;   et al. September 8, 2016

IN-SITU LOADED STAPLER

Abstract

In one aspect of the present disclosure a surgical stapling apparatus is disclosed including a cartridge assembly. The cartridge assembly includes at least one cartridge having a first half and a second half, a first row of retention slots disposed in the first half, a second row of retention slots disposed in the second half, a third row of retention slots being alternately disposed in the first half and the second half of the at least one cartridge between the first and second rows of staple receiving slots, a plurality of fasteners disposed in the retention slots of the first, second and third rows, and a plurality of pushers disposed in each of the first and second halves of the cartridge.


Inventors: Kostrzewski; Stanislaw; (Newtown, CT) ; Aranyi; Ernest; (Easton, CT) ; Scirica; Paul; (Huntington, CT)
Applicant:
Name City State Country Type

Covidien LP

Mansfield

MA

US
Family ID: 1000001957950
Appl. No.: 15/156761
Filed: May 17, 2016


Related U.S. Patent Documents

Application NumberFiling DatePatent Number
13652569Oct 16, 20129364217
15156761

Current U.S. Class: 1/1
Current CPC Class: A61B 17/072 20130101; A61B 17/105 20130101
International Class: A61B 17/10 20060101 A61B017/10; A61B 17/072 20060101 A61B017/072

Claims



1. (canceled)

2. A staple cartridge assembly comprising: a first staple cartridge including: a first cartridge portion including a first row of retention slots and a first tissue contacting surface; a second cartridge portion including a second row of retention slots and a second tissue contacting surface, the second cartridge portion releasably attachable to the first cartridge portion; and a third row of retention slots being alternately disposed in the first cartridge portion and the second cartridge portion of the first staple cartridge, the third row of retention slots disposed between the first and second rows of retention slots and defining a third tissue contacting surface, wherein at least two of the first, second, and third tissue contacting surfaces exist in different planes.

3. The staple cartridge assembly of claim 2, wherein each of the first, second, and third tissue contacting surfaces exist in different planes.

4. The staple cartridge assembly of claim 2, wherein the first staple cartridge further includes: a plurality of fasteners disposed in the retention slots of the first, second, and third rows of retention slots.

5. The staple cartridge assembly of claim 4, wherein the first staple cartridge further includes: a plurality of pushers disposed in each of the first and second cartridge portions, each pusher of the plurality of pushers being disposed in operative association with at least one of the retention slots of the first staple cartridge and being configured to eject a respective fastener from at least one retention slot of the first, second, or third rows of retention slots.

6. The staple cartridge assembly of claim 2, further comprising a second staple cartridge configured to couple to the first staple cartridge at a distal end portion thereof.

7. The staple cartridge assembly of claim 6, wherein the second staple cartridge includes: a third cartridge portion including a fourth row of retention slots and a fourth tissue contacting surface; a fourth cartridge portion including a fifth row of retention slots and a fifth tissue contacting surface, the fourth cartridge portion releasably attachable to the third cartridge portion; and a sixth row of retention slots being alternately disposed in the third cartridge portion and the fourth cartridge portion of the second staple cartridge, the sixth row of retention slots disposed between the fourth and fifth rows of retention slots and defining a sixth tissue contacting surface, wherein at least two of the fourth, fifth, and sixth tissue contacting surfaces exist in different planes.

8. The staple cartridge assembly of claim 7, wherein the first and second staple cartridges define a longitudinal slot therebetween.

9. The staple cartridge assembly of claim 8, wherein the longitudinal slot is configured to facilitate passage of a knife blade therethrough.

10. The staple cartridge assembly of claim 2, further including a cartridge support channel configured to receive the first and second cartridge portions of the first staple cartridge therein and maintain engagement therebetween.

11. The staple cartridge assembly of claim 2, further including a staple magazine disposed in operative association with each retention slot of the first staple cartridge, each staple magazine including a plurality of fasteners therein and configured to supply a fastener of the plurality of fasteners to the corresponding retention slot.

12. The staple cartridge assembly of claim 11, wherein the plurality of fasteners associated with the first row of retention slots has a first size, the plurality of fasteners associated with the second row of retention slots has a second size, and the plurality of fasteners associated with the third row of retention slots has a third size, the first, second, and third sizes being different.

13. The staple cartridge assembly of claim 12, wherein the first size is greater than the third size and the third size is greater than the second size.

14. A method of assembling an end effector, comprising: forming a first staple cartridge by coupling a first cartridge portion to a second cartridge portion, the first staple cartridge includes a first row of retention slots disposed in the first cartridge portion, a second row of retention slots disposed in the second cartridge portion, and a third row of retention slots being alternately disposed in the first cartridge portion and the second cartridge portion, the third row of retention slots disposed between the first and second rows of retention slots; forming a second staple cartridge by coupling a third cartridge portion to a fourth cartridge portion, the second staple cartridge includes a fourth row of retention slots disposed in the third cartridge portion, a fifth row of retention slots disposed in the fourth cartridge portion, and a sixth row of retention slots being alternately disposed in the third cartridge portion and the fourth cartridge portion, the sixth row of retention slots disposed between the fourth and fifth rows of retention slots; and coupling the first staple cartridge and the second staple cartridge such that the first and second staple cartridges are configured for insertion into an elongated support channel.

15. The method of claim 14, wherein coupling the first and second cartridge portions further includes coupling flanges and channels defined on the first cartridge portions with corresponding flanges and channels defined on the second cartridge portion, the channels of the first and second cartridge portions being configured to receive the corresponding flanges of the first and second cartridge portions, respectively.

16. The method of claim 14, further including inserting the first staple cartridge into a first cartridge support channel such that engagement between the first and second cartridge portions is maintained.

17. The method of claim 14, wherein coupling the first and second staple cartridges further includes coupling a distal portion of each respective first and second staple cartridge.

18. The method of claim 14, further including inserting first and second staple cartridges into an elongated support channel.
Description



CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a continuation application of U.S. patent application Ser. No. 13/652,569, filed Oct. 16, 2012, the entire contents of which is incorporated herein by reference.

BACKGROUND

[0002] 1. Technical Field

[0003] This application relates to a surgical stapling apparatus, and more particularly, to a cartridge assembly including multiple cartridge halves and a magazine for reloading the surgical stapling apparatus in-situ.

[0004] 2. Background of Related Art

[0005] Surgical devices wherein tissue is first grasped or clamped between opposing jaw structure and then joined by surgical fasteners are well known in the art. In some instruments a knife is provided to cut the tissue which has been joined by the fasteners. The fasteners are typically in the form of surgical staples but two part polymeric fasteners can also be utilized.

[0006] Instruments for this purpose can include two elongated members which are respectively used to capture or clamp tissue. Typically, one of the members carries a staple cartridge which houses a plurality of staples arranged in at least two lateral rows while the other member has an anvil that defines a surface for forming the staple legs as the staples are driven from the staple cartridge. Generally, the stapling operation is effected by a cam bar, a drive sled or other similar mechanism, that travels longitudinally through the staple cartridge and acts upon the staple pushers to sequentially eject the staples from the staple cartridge. A knife can travel between the staple rows to longitudinally cut and/or open the stapled tissue between the rows of staples. Some staplers apply a double row of staples on each side of the incision by providing a disposable loading unit in which a cam member moves through an elongate guide path between two sets of staggered staple carrying grooves. Staple drive members are located within the grooves and are positioned in such a manner so as to be contacted by the longitudinally moving cam member to effect ejection of the staples from the staple cartridge of the disposable loading unit.

[0007] In endoscopic or laparoscopic procedures, surgery is performed through a small incision or through a narrow cannula inserted through small entrance wounds in the skin. In order to address the specific needs of endoscopic and/or laparoscopic surgical procedures, endoscopic surgical stapling devices have been developed. An example of an endoscopic surgical stapling device is disclosed, for example, in U.S. Pat. No. 8,070,033 to Milliman et al., the entire contents of which is incorporated herein by reference.

[0008] It would be extremely beneficial to provide a surgical device for use during laparoscopic and/or endoscopic surgical procedures that can be employed to provide multiple firings of the surgical device without requiring removal of the surgical device from the surgical site.

SUMMARY

[0009] In accordance with the present disclosure, a surgical stapling apparatus for sequentially applying a plurality of fasteners to body tissue and simultaneously incising tissue is provided. The surgical stapling apparatus is configured to receive a disposable loading unit including a plurality of retention slots disposed in a plurality of rows for receiving a plurality of staples therein. Each retention slot includes a staple magazine operatively associated therewith for supplying staples for subsequent firing.

[0010] In one aspect of the present disclosure a surgical stapling apparatus is disclosed including a handle assembly, an elongated body extending distally from the handle assembly and defining a longitudinal axis, and a disposable loading unit supported at the distal end of the elongated body. The disposable loading unit includes an anvil assembly and a cartridge assembly. The cartridge assembly includes at least one cartridge having a first half and a second half, a first row of retention slots disposed in the first half of the at least one cartridge, a second row of retention slots disposed in the second half of the at least one cartridge, a third row of retention slots being alternately disposed in the first half and the second half of the at least one cartridge between the first and second rows of staple receiving slots, a plurality of fasteners disposed in the retention slots of the first, second and third rows, and a plurality of pushers disposed in each of the first and second halves of the cartridge. Each pusher is disposed in operative association with at least one of the retention slots of the cartridge assembly and is configured to eject a respective fastener from the at least one retention slot during firing of the surgical stapling apparatus.

[0011] In an aspect of the present disclosure, the at least one cartridge is a pair of cartridges configured to couple together at a distal end portion thereof and defining a longitudinal slot therebetween when coupled together.

[0012] In an aspect of the present disclosure, the longitudinal slot is configured to facilitate passage of a knife blade therethrough.

[0013] In an aspect of the present disclosure, the first and second halves of the at least one cartridge include corresponding flanges and channels. The channels of the first and second halves are configured to receive corresponding flanges of the first and second halves, respectively, when the first and second halves are coupled together.

[0014] In an aspect of the present disclosure, the flanges of the first and second halves include the retention slots of the second row therein.

[0015] In an aspect of the present disclosure, the cartridge assembly further includes a cartridge support channel configured to receive the first and second halves of the at least one cartridge therein to maintain the first and second halves in engagement with one another.

[0016] In an aspect of the present disclosure, each retention slot of the at least one cartridge includes a staple magazine disposed in operative association therewith and including a plurality of fasteners therein. The staple magazine is configured to supply one of the plurality of fasteners of the staple magazine to the corresponding retention slot after a firing of the surgical stapling device.

[0017] In an aspect of the present disclosure, the plurality of fasteners disposed in the retention slots and staple magazines of the first row have a first size, the plurality of fasteners disposed in the retention slots and staple magazines of the second row have a second size, and the plurality of fasteners disposed in the retention slots and staple magazines of the third row have a third size. In an aspect of the present disclosure the first, second and third sizes are substantially the same. In another aspect of the present disclosure, the first size is greater than the second and third sizes and the third size is greater than the second size. In another aspect of the present disclosure, the first size is greater than the second and third sizes and the second and third sizes are the same. In another aspect of the present disclosure, the first and second sizes are the same and the third size is smaller than the first and second sizes.

[0018] In an aspect of the present disclosure, the first half defines a first tissue contacting surface, the second half defines a second tissue contacting surface, and the first and second halves, when coupled together, define a third tissue contacting surface. In an aspect of the present disclosure, it is contemplated that a height of each of the first and second tissue contacting surfaces is substantially the same, that a height of the first and third tissue contacting surfaces is substantially the same, that a height of the second and third tissue contacting surfaces is substantially the same or that a height of each of the first, second and third tissue contacting surfaces is substantially the same. In another aspect of the present disclosure, the height of the first tissue contacting surface is greater than one or both of the heights of the second and third tissue contacting surfaces. In another aspect of the present disclosure, the height of the second tissue contacting surface is greater than one or both of the heights of the first and third tissue contacting surfaces. In another aspect of the present disclosure, the height of the third tissue contacting surface is greater than one or both of the heights of the first and second tissue contacting surfaces.

[0019] In an aspect of the present disclosure, the staple magazine includes a biasing member configured to bias the plurality of fasteners disposed in the staple magazine toward the corresponding retention slot. In an aspect of the present disclosure, the biasing member is a leaf spring.

[0020] In an aspect of the present disclosure, each of the plurality of pushers includes at least one pusher plate disposed within at least one of the retention slots of the first, second and third rows. The at least one pusher plate is configured to translate through the respective retention slot to eject the respective fastener disposed therein.

[0021] In an aspect of the present disclosure, each of the plurality of pushers is configured to cover an opening disposed between a respective retention slot and the corresponding staple magazine when translating through the respective retention slot to a fired position to eject the respective fastener disposed therein, and to uncover the opening disposed between the respective retention slot and the corresponding staple magazine when translating back to a pre-fired position after the respective fastener has been ejected from the respective retention slot, thereby allowing the corresponding staple magazine to re-supply the respective retention slot with one of the plurality of fasteners disposed in the corresponding staple magazine.

[0022] In an aspect of the present disclosure, the surgical stapling apparatus includes a firing cam assembly that is translatably disposed within the disposable loading unit. The firing cam assembly includes a plurality of drive bars. Each drive bar includes a firing cam disposed at a distal end thereof and is configured to translate through one of the first and second halves of the at least one cartridge to engage and drive each pusher to eject the fastener from the corresponding retention slot during firing of the surgical stapling apparatus.

[0023] In an aspect of the present disclosure, each of the first and second halves of the at least one cartridge includes a longitudinal slot extending therethrough configured for the reception of one of the plurality of drive bars therethrough.

[0024] In an aspect of the present disclosure, each firing cam includes a camming slot configured to receive the plurality of pushers therein during a distal translation of the firing cam assembly to translate the plurality of pushers between a pre-fired position and a fired position.

[0025] In an aspect of the present disclosure, each pusher includes a proximal camming surface and each camming slot of each firing cam includes a firing cam surface. The firing cam surface is configured to engage the proximal camming surface of the pusher during distal translation of the respective drive bar to translate the pusher to the fired position and cause the pusher to eject the respective fastener from the at least one retention slot.

[0026] In an aspect of the present disclosure, each pusher includes a distal camming surface and each camming slot includes a retracting cam surface. The retracting cam surface is configured to engage the distal camming surface of the pusher during proximal translation of the respective drive bar to cause the pusher to return to the pre-fired position.

[0027] In an aspect of the present disclosure, each camming slot includes a proximal portion proximal of the firing cam surface that is configured to maintain each pusher disposed therein in the fired position.

[0028] In an aspect of the present disclosure, a surgical stapling apparatus is disclosed including a handle assembly, an elongated body extending distally from the handle assembly and defining a longitudinal axis, and a disposable loading unit supported at the distal end of the elongated body. The disposable loading unit includes an anvil assembly and a cartridge assembly. The cartridge assembly includes a plurality of retention slots disposed in a plurality of rows, each retention slot including a fastener disposed therein, and a staple magazine disposed in operative association with each retention slot. The staple magazine includes a plurality of fasteners and a biasing member disposed therein. The biasing member is configured to bias the plurality of fasteners towards the corresponding retention slot. The staple magazine is configured to reload the corresponding retention slot with one of the plurality of fasteners after a firing of the surgical stapling apparatus.

[0029] In an aspect of the present disclosure, the plurality of rows of retention slots include at least a first row of retention slots and a second row of retention slots. In an aspect of the present disclosure, the fasteners disposed in the first row of retention slots have a first size and the fasteners disposed in the second row of retention slots having a second size. In an aspect of the present disclosure, the first size is substantially equal to the second size. In another aspect of the present disclosure, the first size is greater than the second size. In another aspect of the present disclosure, the second size is greater than the first size.

[0030] In an aspect of the present disclosure, the plurality of fasteners of each staple magazine corresponding to the retention slots of the first row have the first size and the plurality of fasteners of each staple magazine corresponding to the retention slots of the second row have the second size.

[0031] In an aspect of the present disclosure, a cartridge assembly for use with a disposable loading unit of a surgical stapling apparatus is disclosed including a first cartridge and a second cartridge coupled to the first cartridge. Each of the first and second cartridges includes a first cartridge half and a second cartridge half and each cartridge half includes a longitudinal slot extending therethrough and a plurality of retention slots disposed therein. Each retention slot includes a fastener disposed therein and each cartridge half further includes a plurality of pushers disposed therein in operative communication with the longitudinal slot and the plurality of retention slots. The cartridge assembly further includes a plurality of drive bars configured for translation through the cartridge assembly. Each drive bar is configured to translate through the longitudinal slot of one of the cartridge halves, whereby upon distal translation of one of the plurality of drive bars through the longitudinal slot of one of the cartridges halves, the one of the plurality of drive bars individually engages each pusher of the respective cartridge half to drive each pusher to sequentially eject the fastener from the associated retention slot.

[0032] Any of the above aspects of the present disclosure described may be combined with any other aspect of the present disclosure without departing from the scope of the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with a general description of the disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure, wherein:

[0034] FIG. 1 is a perspective view of an exemplary surgical stapling apparatus according to the present disclosure;

[0035] FIG. 2 is a perspective view of the surgical stapling apparatus of FIG. 1 with the disposable loading unit detached and the shaft rotated 90.degree.;

[0036] FIG. 3 a perspective view of the disposable loading unit of the surgical stapling apparatus of FIG. 1;

[0037] FIG. 4 is a cross-sectional view of the disposable loading unit of FIG. 3 taken along section line 4-4;

[0038] FIG. 4a is a cross-sectional view of the disposable loading unit of FIG. 3 taken along section line 4-4, illustrating the knife assembly disposed in the central channel and an anvil assembly;

[0039] FIG. 5 is a perspective view of a two plate pusher in accordance with the present disclosure;

[0040] FIG. 6 is a perspective view of the cartridge assembly of the disposable loading unit of FIG. 3;

[0041] FIG. 7 is a exploded view of the cartridge assembly of FIG. 6, illustrating a pair of cartridges and a carrier;

[0042] FIG. 8 is an exploded view of one of the cartridges of FIG. 7, illustrating two cartridge halves and a cartridge support channel;

[0043] FIG. 9 is an exploded view of one of the cartridge halves of FIG. 8, illustrating the pushers, biasing members and fasteners removed;

[0044] FIG. 10 is an enlarged, partially exploded, view of the distal end of one of the cartridge halves of FIG. 8 indicated by the area of detail 10;

[0045] FIG. 11 is a cross-sectional view of the cartridge assembly of FIG. 6, taken along section line 11-11;

[0046] FIG. 12 is an enlarged view of the distal end portion of the cartridge assembly of FIG. 11 indicated by the area of detail 12;

[0047] FIG. 13 is a top down view of the firing cam assembly of the cartridge assembly of FIG. 11;

[0048] FIG. 14 is a perspective view of the firing cam assembly of FIG. 13;

[0049] FIG. 15 is an exploded view of the firing cam assembly of FIG. 14;

[0050] FIG. 16 is a side, cross-sectional view of the cartridge assembly of FIG. 6, taken along section line 16-16; and

[0051] FIGS. 17-19 are enlarged cross-sectional views of the cartridge assembly of FIG. 4 indicated by the areas of detail 17, 18, 19 in FIG. 4, illustrating the firing and re-loading of a retention slot.

DETAILED DESCRIPTION OF EMBODIMENTS

[0052] Embodiments of the presently disclosed surgical stapling apparatus will now be described in detail with reference to the drawings wherein like numerals designate identical or corresponding elements in each of the several views. As is common in the art, the term "proximal" refers to that part or component closer to the user or operator, i.e. surgeon or physician, while the term "distal" refers to that part or component farther away from the user.

[0053] FIGS. 1-2 illustrate one embodiment of the presently disclosed surgical stapling apparatus shown generally as 10. Briefly, surgical stapling apparatus 10 includes a handle assembly 12 and an elongated body 14. A loading unit or DLU 16 is releasably secured to a distal end of elongated body 14. loading unit 16 includes a tool assembly 18 having a cartridge assembly 20 housing a plurality of surgical staples and an anvil assembly 22 pivotably coupled in relation to cartridge assembly 20. A detailed description of the function of handle assembly 12, elongated body 14 and similar features of the loading unit 16 are disclosed in U.S. Pat. No. 8,070,033 to Milliman et al. the entire contents of which are incorporated herein by reference. Once the surgical stapling apparatus 10 has been fired, the practitioner may remove the DLU 16, as described hereinabove, and install a new DLU 16.

[0054] Handle assembly 12 includes a stationary handle member 24, a movable handle member 26, and a barrel portion 28. Movable handle member 26 is operably coupled to loading unit 16 such that upon actuation of movable handle member 26, e.g., relative to stationary handle member 24, loading unit 16 is also actuated to grasp tissue and/or to fire and form fasteners through the grasped tissue.

[0055] A rotatable member 30 is preferably mounted on the forward end of barrel portion 28 to facilitate rotation of elongated body 14 with respect to handle assembly 12. For example, upon actuation, e.g. rotation, of rotatable member 30, elongated body 14 and loading unit 16 are also rotated. Rotatable member 30 may be rotated, for example, up to 180.degree. in each direction.

[0056] Referring now to FIG. 2, with rotatable member 30 rotated 90.degree., a coupling mechanism 15 is shown. Coupling mechanism 15 is operably associated with elongated body 14 and loading unit 16 and is configured to control the coupling therebetween when loading unit 16 is coupled to elongated body 14. Loading unit 16 may be coupled to elongated body 14 by a coupling mechanism 15 such as a bayonet coupling, a snap fit coupling, or a similar coupling and may be secured in place by coupling mechanism 15. A release switch 15a is operatively associated with coupling mechanism 15 and is configured to release or decouple loading unit 16 from elongated body 14. In this manner, a used loading unit 16 may be removed and a new loading unit 16 may be coupled to elongated body 14.

[0057] An articulation lever 32 is also preferably mounted on the forward end of barrel portion 28 adjacent rotatable member 30 to facilitate articulation of tool assembly 18. For example, upon actuation of articulation lever 32 in a first direction, tool assembly 18 may also articulate in the first direction, and upon actuation of articulation lever 32 in a second direction, tool assembly 18 may also articulate in the second direction. It is also contemplated that tool assembly 18 may articulate in a direction opposite to the direction that articulation lever 32 is actuated.

[0058] A retraction member 34 is movably positioned along barrel portion 28 and operatively associated with tool assembly 18. Retraction member 34 is actuatable to return surgical stapling apparatus 10 to a retracted, or pre-fired, position. During operation, as movable handle member 26 is actuated to fire the surgical stapling device, retraction member 32 is translated distally. The position of retraction member 34 is maintained in place by a locking mechanism (not shown). A release button 35 is provided for temporarily deactivating this locking mechanism. Upon actuation of release button 35, retraction member 34 is no longer locked in place.

[0059] Referring to FIG. 3, loading unit 16 includes a proximal housing portion 100 adapted to releasably engage the distal end of body portion 14 (FIGS. 1 and 2). A mounting assembly 102 is pivotally secured to the distal end of housing portion 100, and is configured to receive the proximal end of tool assembly 18 such that pivotal movement of mounting assembly 102 about an axis perpendicular to the longitudinal axis of housing portion 100 effects articulation of tool assembly 18.

[0060] Referring to FIGS. 3-10, tool assembly 18 preferably includes cartridge assembly 20 and anvil assembly 22 having staple forming pockets 22a (FIG. 18) disposed thereon. An example of a suitable anvil assembly 22 is disclosed in U.S. Pat. No. 5,865,361 to Milliman et al., referenced above. Cartridge assembly 20 includes a carrier 202 which defines an elongated support channel 204 (FIG. 7). Elongated support channel 204 is dimensioned and configured to receive a pair of staple cartridges 206, 208. Corresponding tabs 210 and slots 212 formed along staple cartridges 206, 208 and elongated support channel 204, respectively, function to retain staple cartridges 206, 208 within support channel 204. A support strut 214 formed along each staple cartridge 206, 208 is positioned to rest on a side wall of carrier 202 to further stabilize staple cartridges 206, 208 within support channel 204.

[0061] With reference now to FIGS. 6 and 7, staple cartridges 206, 208 are configured to couple together at a distal end portion 216 and define a central longitudinal slot 252 therebetween to facilitate passage of knife assembly 308 (FIG. 14) therethrough. An inner hole 222 formed on a surface of the distal end portion 216 of one of staple cartridges 206, 208 is configured to receive an inner tab 224 formed on a surface of the distal end portion 216 of the other of staple cartridges 206, 208. Inner hole 222 and inner tab 224 function to align staple cartridges 206, 208 when coupled together. Inner hole 222 and inner tab 224 in conjunction with tabs 210, slots 212, and struts 214 also function to maintain staple cartridges 206, 208 in a longitudinally fixed relation when inserted into elongated support channel 204 of carrier 202.

[0062] With reference now to FIG. 8, each staple cartridge 206, 208 includes an inner half 226 and an outer half 228 configured to engage and couple to inner half 226. Each half 226, 228 includes retention slots 230 formed therein for receiving a plurality of fasteners 110 and pushers 108. Each fasteners 110 includes a pair of legs 112 having tips 110d and a backspan 110e. Retention slots 230 are aligned in rows, so that when inner half 226 and outer half 228 are coupled together, for example, three rows of retention slots 230 are defined. It is contemplated that cartridge halves 226, 228 may include fewer rows or additional rows of retention slots.

[0063] Outer half 228 includes a first row 234 of retention slots 230 and at least a portion 236a of a second row 236 of retention slots 230. Inner half 226 includes a third row 238 and at least a remaining portion 236b of the second row 236 of retention slots 230. When outer half 228 and inner half 226 are coupled together, the second row 236 of retention slots 230 is defined by the combination of portions 236a and 236b. For example, portions 236a and 236b may alternately define retention slots 230 of second row 236 as illustrated in FIG. 8.

[0064] Each of inner half 226 and outer half 228 includes a plurality of flanges 240 and a plurality of channels 242. Channels 242 are configured to receive flanges 240 during coupling of inner half 226 to outer half 228 such that the channels 242 of each of inner and outer halves 226, 228 match up with the flanges 240 of the other of inner and outer halves 226, 228 when the inner and outer halves 226, 228 are joined together. Channels 242 and flanges 240 may alternate along the length of each of inner half 226 and outer half 228, as illustrated in FIG. 8. Each flange 240 includes one of retention slots 230 of second row 236. Retention slots 230 of flanges 240 may be configured such that when inner half 226 and outer half 228 are coupled together, flanges 240, and the retention slots 230 disposed therein, are substantially longitudinally aligned to form second row 236. Alternatively, retention slots 230 of flanges 240 of each of inner and outer halves 226 and 228 may be slightly offset from a longitudinal axis such that retention slots 230 of flanges 240 of respective inner and outer halves 226 and 228 are not substantially longitudinally aligned.

[0065] Referring now to FIGS. 4 and 6-8, each cartridge 206, 208 includes a cartridge support channel 254 dimensioned and configured to receive inner and outer halves 226 and 228. Cartridge support channel 254 is configured to maintain inner and outer halves 226 and 228 in engagement in longitudinal alignment with one another. Inner and outer halves 226 and 228 include recessed sections 256 dimensioned and configured for receiving cartridge support channel 254 such that cartridge support channel 254 is substantially aligned with side surfaces 258 of inner and outer halves 226 and 228. This assists in maintaining inner and outer halves 226, 228 coupled together without adding additional width to each cartridge 206, 208 thereby maintaining a minimal width of the overall cartridge assembly 20.

[0066] Referring now to FIG. 4, in any of the embodiments disclosed herein, one or more of the cartridges 206, 208 includes a tissue contacting surface 104 that is stepped. For example, an outer tissue contacting surface 104a, an intermediate tissue contacting surface 104b, and an inner tissue contacting surface 104c form a stepped configuration. Each tissue contacting surface 104a-104c has a different height from one another as measured from a bottom surface 106 of a respective cartridge 206, 208. Specifically, tissue contacting surfaces 104a-104c are planar structures that are substantially parallel to one another, but are not co-planar (i.e. stepped) with one another. In addition, each tissue contacting surface 104a-c defines a planar axis that extends through the respective tissue contacting surface 104a-c. A first wall surface interconnects tissue contacting surfaces 104a and 104b, while a second wall surface interconnects tissue contacting surfaces 104b and 104c. The first and second wall surfaces are planar structures wherein each wall surface defines a planar axis. In one embodiment, the planar axes of the wall surfaces are orthogonal to the planar axes of tissue contacting surfaces 104a-c. In one embodiment, inner tissue contacting surface 104c is defined on inner half 226 of each cartridge 206, 208, outer tissue contacting surface 104a is defined on outer half 228 of cartridge, and intermediate tissue contacting surface 104b is defined by the joining of inner half 226 and outer half 228 when inner and outer halves 226, 228 are coupled together.

[0067] Inner tissue contacting surface 104c has the greatest height, outer tissue contacting surface 104a has the least height, and intermediate tissue contacting surface 104b has a height between the heights of outer and inner tissue contacting surfaces 104a, 104c (see FIG. 4). While tissue contacting surfaces 104a-104c are shown as increasing in height from outer most tissue contacting surface 104a to inner most tissue contacting surface 104c, it is within the scope of the present disclosure that the heights of each tissue contacting surface can vary depending on the particular surgical procedure. For example, tissue contacting surfaces 104a-104c can increase in height from the inner most tissue contacting surface 104c to the outer most tissue contacting surface 104a, the intermediate tissue contacting surface 104b can have the greatest height, the intermediate tissue contacting surface 104b can have the least height, or at least two of tissue contacting surfaces 104a-104c can have the same height.

[0068] As seen in FIG. 4, each row 234, 236, 238 may include fasteners 110 having different sizes. For example, legs 112a of surgical fasteners 110a disposed in retention slots 230 of first row 234 may have a first leg length, legs 112b of surgical fasteners 110b disposed in retention slot 230 of second row 236 may have a second leg length, and legs 112c of surgical fasteners 110c disposed in retention slot 230 of third row 238 may have a third leg length. In particular, surgical fasteners 110a-110c increase in height from the inner most row 238 to the outermost row 234 of each cartridge. In one embodiment, legs 112c of surgical fasteners 110c have a leg length of about 2.3 mm, legs 112b of surgical fasteners 110b have a leg length of about 3.5 mm, and legs 112a of surgical fasteners 110a have a leg length of about 4.1 mm. As such, inner tissue contacting surface 104c has the greatest height and retains surgical fasteners 110c having the shortest leg lengths, and outer tissue contacting surface 104a has the least height and retains surgical fasteners 110a having the longest leg lengths. Tissue contacting surface 104 step progressively downward at intermediate tissue contacting surface 104b and then again at outer tissue contacting surface 104a. It is envisioned and within the scope of the present disclosure that any number of arrangements are possible. In any of the embodiments disclosed herein, the cartridge or cartridges can include staples of different sizes or the cartridge or cartridges can have staples that are all the same size.

[0069] With reference now to FIGS. 4 and 8-10, each retention slot 230 of inner and outer halves 226 and 228 has a staple magazine 244 operatively associated therewith. The staple magazine is positioned in a flange 240. Each staple magazine 244 includes a plurality of fasteners 110 disposed therein and a biasing member 246 configured to bias and urge the plurality of fasteners 110 towards the respective retention slot 230. As discussed above, retention slots 230 that are disposed on different rows 234, 236 and 238 may include fasteners 110 having different sizes. It is further contemplated that each magazine 244 associated with an adjacent retention slot 230 includes a plurality of fasteners 110 having the same size as the fastener 110 disposed in the adjacent retention slot 230. For example, magazines 244 associated with retention slots 230 of first row 234 may include fasteners 110a have the first size, magazines 244 associated with retention slots 230 of second row 236 may include fasteners 110b have the second size, and magazines 244 associated with retention slots 230 of third row 238 may include fasteners 110c have the third size.

[0070] Referring now to FIG. 10, staple magazine 244 generally defines a "U" or "H" shaped channel 248 for reception of fasteners 110 therein. Channel 248 includes a pair of vertical segments 248a, 248b and a horizontal segment 248c. With reference to FIG. 5, each fastener 110 disposed within channel 248 is maintained in a vertical orientation, with tips 110d oriented toward the tissue contacting surface 104 of the respective cartridge 206, 208, and aligned parallel to a plane defined by the fastener 110 disposed within the respective retention slot 230. For example, the backspan 110e of a fastener 110 disposed within channel 248 of magazine 244 rests on horizontal segment 248c and the legs 112 of the fastener 110 disposed within channel 248 are disposed within vertical segments 248a and 248b. This ensures that when a fastener 110 is loaded from a magazine 244 into a respective retention slot 230, the fastener 110 is properly oriented toward the tissue contacting surface 104 for firing.

[0071] Each magazine 244 includes at least one channel 244a for receiving at least a portion of biasing member 246 therethrough where biasing member 246 is configured to extend from the at least one channel 244a into at least one of vertical segments 248a and 248b adjacent the plurality of fasteners 110 disposed in magazine 244 to engage the plurality of fasteners 110 and urge the plurality of fasteners 110 towards the respective retention slot 230. It is contemplated that a separate biasing member 246 may extend into each vertical segment 248a and 248b. In an embodiment, biasing member 246 includes a pair of legs 246b, 246c, and a backspan 246d where the pair of legs 246b, 246c extends into vertical segments 248a, 248b, respectively when biasing member 246 is inserted into channel 244a of magazine 244.

[0072] With reference now to FIG. 4, legs 246b and 246c of biasing member 246 may define a slight curve such that when biasing member 246 is inserted into channel 244a of magazine 244 and engages the plurality of fasteners 110 disposed therein, legs 246b and 246c bias the plurality of fasteners 110 toward the respective retention slot 230 and in vertical registration with the respective retention slot 230. Biasing member 246 is inserted into channel 244a in a substantially vertical manner and upon encountering one in the plurality of fasteners 110, legs 246b and 246c are deflected outward and engage the plurality of fasteners with a biasing force "F". Biasing member 246 may be formed of any resilient or flexible material which resists deformation or applies a force to return to its pre-deformation state.

[0073] Biasing member 246 may be any suitable mechanism for biasing the plurality of fasteners 110 disposed in magazine 244 toward retention slot 230, as described above, including, for example, springs, resilient members, or other similar biasing elements. In one embodiment, biasing member 246 is a leaf spring 246a having a substantially "U" shape. It is contemplated that biasing member 246 may have other shapes suitable for use in biasing fasteners 110 disposed in magazine 244 toward retention slot 230.

[0074] With reference now to FIGS. 4, 5, 9, and 16-19, a plurality of pushers 108 are disposed within each of the inner and outer halves 226, 228 of cartridges 206, 208 and are operatively associated with the plurality of retention slots 230. Each pusher 108 includes a pusher plate 108c disposed within one of retention slots 230 and in operative association with the fastener 110 disposed within the respective retentions slot 230. Each pusher plate 108c is configured to translate through the respective retention slot 230 to urge the fastener 110 disposed therein out of the retention slot 230 through a respective opening 230a in tissue contacting surface 104, through tissue disposed between anvil assembly 22 and the cartridge assembly 20, and against staple forming pockets 22a (FIG. 18) of anvil assembly 22.

[0075] In one embodiment, as illustrated in FIG. 4, pusher plates 108c disposed in the retention slots 230 of first row 234 may have a first size, pusher plates 108c disposed in the retention slots 230 of second row 236 may have a second size, and pusher plates 108c disposed in retention slots 230 of third row 238 may have a third size. For example, pusher plates 108c of the first row 234 may be smaller than pusher plates 108c of second row 236, and pusher plates 108c of second row 236 may be smaller than pusher plates 108c of third row 238. Having pusher plates 108c with different sizes allows pusher plates 108c to accommodate fasteners 110a-110c having different sizes or allows pusher plates 108c to accommodate rows 234, 236, 238 having tissue contacting surfaces 104a-c of different heights. Pusher plates 108c of each pusher 108 may alternatively be the same size. A tray or other member may be provided to maintain the position of the pushers prior to the staple cartridge being installed in the cartridge support channel.

[0076] Each pusher 108 may be operatively associated with one or more retention slots 230 such that upon actuation thereof, pusher 108 may fire one or more fasteners 110 out of retention slots 230 through openings 230a. For example, as illustrated in FIG. 5, a pusher 108a including two pusher plates 108c is configured to fire two fasteners 110. As illustrated in FIG. 9, cartridge halves 226, 228 may include more than one type of pusher where, for example, pushers 108a, including two pusher plates 108c, that are configured for operative association with two retention slots 230 may be disposed at either end of the respective row 234, 236, 238, and pushers 108b, including three pusher plates 108c, that are configured for operative association with three retention slots 230 may be disposed between the ends of the respective rows 234, 236, 238. It is contemplated that alternate arrangements are possible where two and three retention slot pushers 108a, 108b may be included in any order. Alternatively, only one type of pusher 108 may be used, e.g., only pushers 108a configured for use with two retention slots or only pushers 108b configured for use with three retention slots. In this manner, each retention slot 230 is operatively associated with a pusher 108 that is configured to fire a fastener 110 disposed therein. It is alternatively contemplated that each pusher 108 may only include one pusher plate 108c and may only be associated with a single retention slot 230 or that each pusher 108 may include a plurality of pusher plates 108c configured for use with a plurality of retention slots 230.

[0077] Referring now to FIGS. 17-19, during firing, as a pusher plate 108c translates through a corresponding retention slot 230 to a fired position, pusher plate 108c at least partially blocks or covers an opening 232 between retention slot 230 and magazine 244 to inhibit reloading of retention slot 230 with a new fastener 110 by magazine 244 until the firing stroke is complete. As pusher plate 108c returns to its pre-fired position at the base of retention slot 230, opening 232 is uncovered or opened to magazine 244 and receives the next fastener 110 from magazine 244 due to biasing force "F" of biasing member 246. It is contemplated that the next fastener 110 from magazine 244 may be at least partially received through opening 232 and within retention slot 230 as pusher plate 108c returns toward its pre-fired position where, for example, tips 110d of the next fastener 110 may be received through opening 232 and within retention slot 230 before backspan 110e is received through opening 232 and within retention slot 230.

[0078] Referring now to FIGS. 11-19, a firing cam assembly 300 is disposed at least partially within proximal housing 100 of loading unit 16 and extends at least partially into tool assembly 18. Firing cam assembly 300 is disposed in operative communication with handle assembly 12 and is configured to translate distally and proximally through tool assembly 18 upon actuation of handle assembly 12, as will be described below in more detail.

[0079] With reference now to FIGS. 13-15, firing cam assembly 300 includes a plurality of drive bars 302 having firing cams 304 disposed at a distal end thereof and a central drive member 306 having a knife assembly 308 disposed at a distal end thereof. Knife assembly 308 defines a substantially I-shaped cross section having a top flange 306a, a bottom flange 308b and a knife blade 308c. As discussed above, a central longitudinal slot 252 extends along the length of cartridge assembly 20 between staple cartridges 206, 208 to facilitate passage of central drive member 306 and knife assembly 308 therethrough. With reference now to FIG. 4A, top flange 308a is configured to translate through a longitudinal slot 22b of anvil assembly 22 and bottom flange 308b is configured to translate longitudinally along an underside 202a of carrier 202.

[0080] With reference now to FIG. 11, each half 226, 228 of each cartridge 206, 208 includes a longitudinal slot 250 extending at least partially therethrough to accommodate passage of at least one of drive bars 302 and firing cams 304 of firing cam assembly 300 therethrough. It is contemplated, for example, that each slot 250 may accommodate passage of a single drive bar 302 and firing cam 304 or may accommodate passage of multiple drive bars 302 and firing cams 304.

[0081] With reference now to FIG. 4A, during operation of surgical stapling apparatus 10, as firing cam assembly 300 translates through loading unit 16, knife assembly 308 translates through longitudinal slot 250 with top flange 306a translating through longitudinal slot 22a of anvil assembly 22 and bottom flange 306b translating along underside 202a of carrier 202 to approximate anvil assembly 22 and cartridge assembly 20 together. As knife assembly 308 translates through slot 250, knife blade 308c severs the portion of tissue that is disposed between anvil assembly 22 and cartridge assembly 20 adjacent slot 250.

[0082] With reference now to FIGS. 11, 12 and 16-19, as firing cam assembly 300 translates through loading unit 16, drive bars 302 of firing cam assembly 300 translate through the longitudinal slots 250 of each half 226, 228 of each staple cartridge 206, 208. The Firing cams 304 are advanced into sequential contact with the pushers 108 associated with retention slots 230, to cause pusher plates 108c to translate vertically within retention slots 230 and urge fasteners 110 from retention slots 230 through openings 230a in tissue contacting surface 104, through tissue disposed between anvil assembly 22 and the cartridge assembly 20, and against staple forming pockets 22a of anvil assembly 22 for staple forming.

[0083] As illustrated in FIGS. 11, 13 and 14, drive bars 302 are initially disposed adjacent to one another within proximal housing 100 of loading unit 16 and are resilient or flexible such that they may spread out to translate through longitudinal slots 250.

[0084] Referring now to FIGS. 11 and 13-15, firing cam assembly 300 may include, for example, four pairs of drive bars 302a-302d including four pairs of corresponding firing cams 304a-304d. Each pair of drive bars 302a-302d corresponds to a respective longitudinal slot 250a-250d of cartridges 206, 208 and is translatable through the respective longitudinal slot 250a-250d to actuate pushers 108 disposed in the respective longitudinal slot 250a-250d to effect firing of fasteners 110 disposed in corresponding retention slots 230. Drive bars 302a-302d and central drive member 306 are coupled together at the proximal end by a retaining member 307.

[0085] Referring now to FIGS. 5 and 16, each pusher 108 includes a pusher base 108d having a proximal cam surface 108e and a distal cam surface 108f. Each pusher base 108d is disposed within one of longitudinal slots 250 with the proximal and distal cam surfaces 108e, 108f being configured for engagement with at least one of firing cams 304 upon distal translation thereof to cause pusher 108 to translate toward tissue contacting surface 104. Translation of pusher 108 in turn causes translation of a corresponding pusher plate 108c through a corresponding retention slot 230 toward tissue contacting surface 104 to eject fasteners 110 from the corresponding retention slots 230.

[0086] Referring now to FIGS. 14-16, each drive bar 302 and firing cam 304 includes a camming slot 310 having a proximal portion 310a and a distal portion 310b. Distal portion 310b includes an opening 312, a firing cam surface 314 and a retracting cam surface 316. Opening 312 is configured to receive pusher base 108d therethrough such that the proximal cam surface 108e of pusher base 108d engages firing cam surface 314 during distal translation of the firing cam 304. Firing cam surface 314 is sloped such that as proximal cam surface 108e of pusher base 108d slides along firing cam surface 314, pusher 108 is urged toward tissue contacting surface 104 from a pre-fired position to a fired position. As pusher 108 is urged toward tissue contacting surface 104, the corresponding pusher plate 108c translates through the corresponding retention slot 230 to drive the fastener 110 disposed in the retention slot 230 through the opening 230a of tissue contacting surface 104, through tissue disposed between anvil assembly 22 and cartridge assembly 20, and against a staple forming pocket 22a of anvil assembly 22.

[0087] Once the pusher base 108d reaches the fired position at a top portion 314a of firing cam surface 314, drive bar 302 and firing cam 304 are further translated distally such that pusher base 108d slides along camming slot 310 towards proximal portion 310a. Proximal portion 310a of camming slot 310 is dimensioned such that as drive bar 302 and firing cam 304 continue to translate distally, pusher base 108d remains in the fired position. This allows the corresponding pusher plate 108c to remain in a position which at least partially blocks or covers the opening 232 of retention slot 230 (FIG. 18) to inhibit loading of the next fastener 110 from the corresponding magazine 244 associated with the respective retention slot 230. Camming slot 310 extends a sufficient distance along drive bar 302 to accommodate a full firing stroke of firing cam assembly 300 where, for example, when drive bar 302 and firing cam 304 are in a distal most position, a proximal end 310c of camming slot 310 is disposed adjacent to or proximal of the proximal most pusher 108.

[0088] During retraction of firing cam assembly 300 after the firing stroke, the distal cam surfaces 108f of pushers 108 are engaged by retracting cam surface 316 as drive bar 302 and firing cam 304 are translated proximally and are driven along retracting cam surface 316 toward opening 312 of camming slot 310 to return the pusher 108 from the fired position to the pre-fired position. As each pusher 108 slides along retracting cam surface 316 of firing cam 304 toward the pre-fired condition, the corresponding pusher plate 108c translates toward a base of the corresponding retention slot 230 and opens up or uncovers the opening 232 of the corresponding retention slot 230 to the corresponding magazine 244. Once opening 232 is uncovered, retention slot 230 receives the next fastener 110 from the magazine 244 due to the biasing force of biasing member 246. Once firing cam assembly 300 is fully retracted and each retention slot 230 has been loaded with a new fastener 110 from a corresponding magazine 244, surgical stapling apparatus 10 is ready to perform an additional firing stroke.

[0089] Referring now to FIGS. 4 and 6-10 the assembly of cartridge assembly 20 will now be described. With reference to FIGS. 4 and 9, a staple pusher 108 is positioned in operative association with each retention slot 230 with pusher base 108d being disposed in one of longitudinal slots 205 of each half 226, 228 of each cartridge 206, 208. Fasteners 110 are loaded into retention slots 230 and magazines 244 through the "U" or "H" shaped channels 248 and the biasing members 246 are inserted into the channels 244a of the magazines 244 such that legs 246b, 246c extend into the vertical segments 248a, 248b of channels 248 and bias the fasteners 110 toward retention slots 230.

[0090] Once the components of each half 226, 228 of each cartridge 206, 208 have been assembled, inner and outer halves 226, 228 of each cartridge 206, 208 are joined or coupled together with the flanges 240 and channels 242 of each half 226, 228 interlocking. The assembled inner and outer halves 226, 228 are then inserted into the cartridge support channel 254 which maintains inner and outer halves 226 and 228 in engagement with one another.

[0091] Referring now to FIGS. 6 and 7, the assembled cartridges 206, 208 are joined together at the distal end portion 216 by inner tab 224 and inner hole 222 so as to define the central longitudinal slot 252 therebetween and the joined cartridges 206, 208 are inserted into elongated support channel 204 of carrier 202 such that tabs 210 disposed on cartridges 206, 208 are engaged with slots 212 of carrier 202 and support struts 214 of cartridges 206, 208 rest on the side walls of carrier 202. The cartridge assembly 20 is now assembled and ready for use.

[0092] The operation of surgical stapling device 10 during a surgical procedure will now be discussed with reference to FIGS. 1, 4A, 12, 13, and 16-18. During the surgical procedure, the surgeon attaches the loading unit 16 to the elongated body 14 and inserts the loading unit 16 into the surgical site. The surgeon then positions tissue between cartridge assembly 20 and anvil assembly 22 and actuates handle assembly 12 to approximate the anvil assembly 22 with the cartridge assembly 20 to grasp the tissue disposed therebetween, as described above. The surgeon further actuates handle assembly 12 to drive firing cam assembly 300 distally through cartridge assembly 20 to fire the surgical fasteners. It is contemplated that a single actuation of handle assembly 12 by the surgeon may grasp tissue and fully fire the surgical stapling device 10. Alternatively, grasping tissue and firing of the surgical stapling device may require multiple actuations of handle assembly 12 with each actuation advancing firing cam assembly 300 a predetermined distance through DLU 16. It is contemplated that the handle portion can be a motorized handle assembly. Such motorized handle assembly can include a controller and/or power source.

[0093] As firing cam assembly 300 translates through cartridge assembly 20, each pair of drive bars 302a-302d and attached pairs of firing cams 304a-304d translate through respective longitudinal slots 250 of one of inner and outer halves 226, 228, of cartridges 206, 208. During distal translation of firing cams 304a-304d, each firing cam 304 individually engages each pusher 108 of each cartridge 206, 208 and sequentially drives each pusher 108 towards the tissue engaging surface 104 and thereby eject fasteners 110 from the retention slots 230 disposed in cartridges 206, 208.

[0094] As discussed above, with reference to FIGS. 16-19, as each firing cam 304 engages each pusher 108, the proximal cam surface 108e of each pusher 108 engages the firing cam surface 314 of each firing cam 304 and is driven up the firing cam surface 314 from the pre-fired position to the fired position, e.g., towards tissue contacting surface 104. As each pusher 108 is driven towards tissue contacting surface 104, each pusher plate 108c translates through a corresponding retention slot 230 to eject a corresponding fastener 110 from the corresponding retention slots 230 through a respective opening 230a in tissue contacting surface 104, through tissue disposed between anvil assembly 22 and cartridge assembly 20, and against staple forming pockets 22a of anvil assembly 22, thereby forming each fastener 110. As the firing cam 304 continues to translate distally, pusher base 108d travels along camming slot 310 toward proximal end portion 310a and is maintained in the fired position, e.g., driven toward tissue contacting surface 104, such that the corresponding pusher plate 108c blocks or covers the opening 232 between the retention slot 230 and the corresponding magazine 244. As firing cam assembly 300 translates distally, knife assembly 308 also translates distally through central longitudinal slot 252 to sever the tissue held between the cartridge assembly 20 and anvil assembly 22.

[0095] Once the firing stroke is complete, with firing cam assembly 300 disposed in a distal most position, the surgeon withdraws retraction member 34 proximally to translate firing cam assembly 300 proximally. As firing cam assembly 300 translates proximally through cartridge assembly 20, firing cams 304 are translated proximally through longitudinal slots 250 such that the distal cam surface 108f of each pusher base 108d engages the retracting cam surface 316 to drive the pusher base 108d down toward opening 312 and the pre-fired position. As each pusher base 108d is driven toward opening 312, each pusher is translated away from tissue contacting surface 104 and each pusher plate 108c is translated away from tissue contacting surface 104 toward the pre-firing position within a corresponding retention slot 230. As each pusher plate 108c is withdrawn to the pre-firing position, the opening 232 between the retention slot 230 and the corresponding magazine 244 is opened or uncovered to allow the next fastener 110 to be received within the retention slot 230 due to the biasing force "F" of the corresponding biasing member 246. Once firing cam assembly 300 is fully translated proximally to a pre-firing position, each retention slot 230 has been reloaded and surgical stapling apparatus 10 is ready for a second firing stroke. In this manner, each retention slot 230 is reloaded in-situ and ready for subsequent use without requiring the surgeon to withdraw the loading unit 16 from the surgical site or replace the loading unit.

[0096] It is contemplated that each loading unit 16 may be configured for multiple firing strokes.

[0097] In any of the embodiments disclosed herein, the drive bars 302 can be configured as more than one bar partially attached to each other. As shown in FIG. 15, each drive bar is comprised of two drive bars. Each bar can be attached, or partially attached, to at least one other adjacent bar, in any of the embodiments disclosed herein. They may be attached by adhesives or welding. For example, a drive bar comprised of two bars are welded together at the distal end, near the cam surface. Each staple pusher is driven by a pair of such cam bar assemblies, as described in par. 0079 thru 0085. The assembly has better flexibility and permits articulation. Welding two or more bars together gives the bar assembly more stiffness and is desirably welded near the cam surface 304. In any of the embodiments disclosed herein, a pair of relatively thinner bars is used, instead of a single relatively thicker bar, which are at least partially attached to one another.

[0098] It is contemplated that individual features of the above described embodiments may be combined without departing from the scope of the present disclosure.

[0099] Although the illustrative embodiments of the present disclosure have been described herein with reference to the accompanying drawings, the above description, disclosure, and figures should not be construed as limiting, but merely as exemplifications of particular embodiments. It is to be understood, therefore, that the disclosure is not limited to the precise embodiments described herein, and that various other changes and modifications may be effected by one skilled in the art without departing from the scope or spirit of the present disclosure.

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