AU2014203092B2 - Surgical stapler - Google Patents

Description

1 SURGICAL STAPLER Technical Field The present disclosure relates to a surgical stapling device and more particularly to a surgical stapling device having pusher-engaging cam members that are slidable on offset planes. Background of the Related Art There are several known types of surgical stapling instruments specifically adapted for use in various procedures. In many such surgical devices, tissue is first grasped or clamped between opposing jaw structures and then joined by surgical fasteners. *The fasteners are typically in the form of surgical staples. These staples generally include a pair of legs adapted to penetrate tissue and connected by a backspan from which they extend. In use, the staples are formed to a "B" configuration. Two part fasteners are also known and include legs that are barbed and connected by a backspan which are engaged and locked into a separate retainer piece that is usually located in the anvil. In some devices, a knife is provided to cut the tissue which has been joined by the fasteners. In these devices, one of the jaw structures carries a staple cartridge having one or more laterally spaced rows of staples, which are aligned with corresponding rows of anvil depressions on an opposing jaw structure. The tissue is initially gripped or clamped such that individual fasteners can be ejected from the cartridge, through the slots, and forced through the clamped tissue. The staples are ejected by longitudinal movement of a driver and forced through the clamped tissue, forming against the staple forming depressions of the anvil. The staples can be arranged in a linear or non-linear row. A common issue in transecting tissue and/or in anastomosis procedures employing the surgical stapling instruments is the balance between anastomotic strength and the degree of hemostasis achievable. It is known to include different size staples in a surgical stapling instrument having a constant gap (uniform distance) between an anvil and a staple cartridge. A common concern in these surgical procedures is hemostasis, or the rate at which bleeding of the target tissue is stopped. It is commonly known that by increasing the amount of pressure applied to a wound, the flow of blood can be limited, thereby decreasing the time 2 necessary to achieve hemostasis. To this end, conventional surgical fastening apparatus generally apply two or more rows of fasteners about the cutline to compress the surrounding tissue in an effort to stop any bleeding and to join the cut tissue together. Each of the fasteners will generally apply a compressive force to the tissue sufficient to effectuate hemostasis, however, if too much pressure is applied, this can result in a needless reduction in blood flow to the tissue surrounding the cut-line. Accordingly, the joining of tissue together in this manner may result in an elevated level of necrosis, a slower rate of healing, and/or a greater convalescence. On the other hand, if not enough pressure is applied, proper hemostasis may not be achieved. Consequently, it would be advantageous to provide a surgical fastening apparatus capable of limiting the flow of blood in the tissue immediately adjacent the cut tissue to effectuate hemostasis and wound closure, while maximizing blood flow in the surrounding tissue to facilitate healing. Object It is the object of the present invention to substantially overcome or ameliorate one or more of the disadvantages of the prior art, or at least provide a useful alternative. Summary There is disclosed herein a surgical fastener applying apparatus, comprising: a cartridge assembly including a plurality of fasteners, and a plurality of fastener pushers positioned beneath the fasteners, each of the fastener pushers defining an equivalent height; an anvil assembly movably connected to the cartridge assembly, the anvil assembly being configured and dimensioned to form the fasteners upon ejection from the cartridge assembly; first and second cam bars movable through the cartridge assembly to facilitate displacement of the fastener pushers and ejection of the fasteners from the cartridge assembly; and a supporting member fixedly positioned within the cartridge assembly beneath the first and second cam bars, the first cam bar being slidable along a first surface of the supporting member, and the second cam bar being slidable along a second surface of the supporting member, the first and second surfaces of the supporting member being positioned at different heights, wherein prior to firing of the surgical fastener applying apparatus, the fastener pushers 3 are spaced apart from the first and second surfaces of the supporting member to facilitate engagement with the first and second cam bars. Preferably, the plurality of fasteners include a first set of fasteners each having legs defining a first length, and a second set of fasteners each having legs defining a second, greater length. Preferably, the first surface of the supporting member defines a first height, and the second surface of the supporting member defines a second height, the first height being greater than the second height. Preferably, the apparatus further includes a third cam bar slidable along the first surface of the supporting member and a fourth cam bar slidable along the second surface of the supporting member such that the second cam bar and the fourth cam bar are positioned radially outward of the first cam bar and the third cam bar. Preferably, the cartridge assembly includes a longitudinal track extending therethrough configured and dimensioned to accommodate movement of a cutting member, the first and third cam bars being positioned on opposite sides of the track, and the second and fourth cam bars being positioned on opposite sides of the track. Preferably, the first cam bar and the second cam bar define equivalent heights. Preferably, the first and second cam bars are configured and dimensioned such that the pushers are displaced transversely in relation to a direction of movement of the first and second cam bars. Preferably, the first cam bar defines a first camming surface and the second cam bar defines a second camming surface, the first camming surface extending transversely in relation to the first surface of the supporting member, and the second camming surface extending transversely in relation to the second surface of the supporting member. Preferably, the first and second cam bars each include a distally tapered configuration such that a distance defined between the first camming surface and the first surface of the supporting 4 member decreases in a distal direction, and a distance defined between the second camming surface and the second surface of the supporting member decreases in a distal direction. Preferably, the first cam bar is connected to the second cam bar such that the first and second cam bars move as a single unit. There is further disclosed herein a cartridge assembly for use in a surgical fastener applying apparatus, the cartridge assembly comprising: a plurality of first fasteners each having legs defining a first length, and a plurality of second fasteners each having legs defining a second, greater length; a plurality of first fastener pushers positioned beneath the first fasteners, and a plurality of second fastener pushers positioned beneath the second fasteners, each of the first and second fastener pushers defining an equivalent height; first and second cam bars movable through the cartridge assembly to facilitate displacement of the fastener pushers and ejection of the fasteners from the cartridge assembly; and a supporting member positioned within the cartridge assembly, the supporting member including a first surface supporting the first cam bar such that the first cam bar is slidable along the first surface into engagement with the plurality of first fastener pushers, and a second surface supporting the second cam bar such that the second cam bar is slidable along the second surface into engagement with the plurality of second fastener pushers, the first surface of the supporting member defining a first height, and the second surface of the supporting member defining a second height, the first height being greater than the second height. Preferably, the assembly further includes a longitudinal track extending therethrough configured and dimensioned to accommodate movement of a cutting member. Preferably, the plurality of first fasteners are arranged into first and second rows positioned on opposite sides of the longitudinal track, and the plurality of second fasteners are arranged into first and second rows positioned on opposite sides of the longitudinal track. Preferably, the cartridge assembly further includes a third cam bar slidable along the first surface of the supporting member and a fourth cam bar slidable along the second surface of the supporting member such that the first cam bar and the third cam bar are positioned beneath the rows of first fasteners on opposite sides of the longitudinal track, and the second cam bar and 5 the fourth cam bar are positioned beneath the rows of second fasteners on opposite sides of the longitudinal track. There is still further disclosed herein a cartridge assembly for use in a surgical fastener applying apparatus, the cartridge assembly comprising: a plurality of fasteners, and a plurality of fastener pushers positioned beneath the fasteners, each of the fastener pushers defining an equivalent height; first and second cam bars movable through the cartridge assembly to facilitate displacement of the fastener pushers and ejection of the fasteners from the cartridge assembly; and a supporting member fixedly positioned within the cartridge assembly beneath the first and second cam bars, the first cam bar being slidable along a first surface of the supporting member, and the second cam bar being slidable along a second surface of the supporting member, the first and second surfaces of the supporting member being positioned at different heights, wherein prior to firing of the surgical fastener applying apparatus, the fastener pushers are spaced apart from the first and second surfaces of the supporting member to facilitate engagement with the first and second cam bars. Brief Description of the Drawings Preferred embodiments of the invention will be described hereinafter, by way of examples only, with reference to the accompanying drawings. Figure 1 is a view in partial cross-section showing the cams bars on different planes; Figure 2 is a perspective view of two cam bars and two staple pushers of Figure 1; Figure 2A is a perspective view of a portion of the cam bars and cam bar support separated from the supporting channel; Figure 3 is a perspective view of one embodiment of a surgical stapler having the offset cam bars of Figure 1; Figure 4 is a perspective view of the surgical stapler of Figure 3 with the anvil and cartridge assemblies separated; 6 Figure 5 is a perspective of an alternate embodiment of a surgical stapler of the present disclosure having offset camming members; and Figure 6 is an exploded perspective view of the distal portion of the surgical stapler of Figure 5. Detailed Description of Embodiments Embodiments of the presently disclosed stapler 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 further away from the user. Figures 1 and 2 illustrate a first embodiment of the cam bar/pusher arrangement of the present disclosure. Figures 3 and 4 illustrate one type of surgical stapler that can incorporate the cam bar/pusher arrangement of Figure 1. Turning first to Figures 3 and 4, the stapler 10 has a cartridge receiving half section 12, an anvil half section 14, and handles 48 and 50 for facilitating clamping of the sections 12 and 14. Cartridge half section 12 has a channel 18 (Fig. 2A) to receive cartridge assembly 16 which includes a plurality of staples 130 and a plurality of pushers 120 to advance the staples 130 from the cartridge 19 through slots 23. A cam bar assembly is advanced by distal advancement of manual firing lever 56. The cam bar assembly is slidable on cam bar supporting member 150 for longitudinal advancement in the cartridge 19 to advance the pushers 120 in a direction substantially transverse to the longitudinal axis of the stapler and substantially transverse to the direction of movement of the cam bars. Engagement of the pushers 120 by the cam members advances the staples 130 through the tissue and into contact with the anvil depressions of the anvil half section 14. Preferably there are two staggered rows of slots 23 formed on either side of a slotted knife track in the cam bar assembly which guides a knife between the rows of staples. A single staple is positioned in each of the slots 23. Staple pushers 120 are aligned with each slot 23 so that a single staple pusher is positioned under the staple retained in the slot. The pushers can optionally be attached to each other in groups of two offset oriented pusher pairs. More details of the stapler are disclosed in commonly assigned U.S. Patent No. 7,140,527, 7 issued November 28, 2006, and U.S. Patent No. 7,055,730, issued January 6, 2006, the entire contents of each of these applications is incorporated herein by reference. With reference to Figures 1 and 2 illustrating the cam member arrangement of the present disclosure, the pushers 120 are advanced by the camming surfaces 1 12a, 1 12b of cam members 110a, I1Ob which as shown are in the form of cam bars 110a, 1Ob. Figure 2 illustrates a distal portion of two of the cam bars 110, 11Ob and two of the pushers 120a, 120b; Figure 1 illustrates four cam bars (11 Oa-1 Od) and four of the pushers 120a-120d. The camming surfaces 1 12a, 1 12b are preferably longitudinally staggered with respect to each other to distribute the firing forces. More specifically, four cam bars (members) 1 Oa-1 10d, four pushers 120a- 120d and four staples 130a- 130d are shown in Figure 1. The cam bars 1 Oa-1 Od are preferably of substantially the same size (height) and angle. The staple pushers 120a-120d are also preferably of substantially the same size (height). Cartridge half section 12 also includes a cam bar (member) supporting member 150 fixedly mounted within channel 18 and having an offset plane 151 on its upper surface. The upper surface includes a lower surface portion 152 and a substantially parallel upper surface portion 154 on each side of the longitudinal centerline and which form surfaces on which the respective cam bars (members) 1 Oa-1 10d slide distally to sequentially fire a longitudinal row of staples contained in the staple cartridge 19. As shown, cam bar 1 10a is positioned on (and slidable longitudinally along) lower surface portion 152 of offset plane 151 and is in contact with pusher 120a, which contacts staple 130a. Cam bar 1 l0b is positioned on (and slidable longitudinally along) upper surface portion 154 of offset plane 151 and is in contact with pusher 120b, which contacts staple 130b. Similar to cam bar 1 10b, cam bar 1 10c is positioned on upper surface portion 154; similar to cam bar 1 10a, cam bar 1 10d is positioned on lower surface portion 152 to contact respective pushers 120c, 120d to fire staples 130c, 130d. Thus, cam bars 110a and 110d are outboard of cam bars I10b, 110c. As can be appreciated with reference to the Figures, the difference in heights of surface portions 152, 154 of offset plane 151 enables staples 130 of different sizes (leg lengths) to be fired into anvil pockets of anvil assembly 14 (shown schematically in Figure 1) for formation by the anvil. Accordingly, the staples of smaller sizes (130b and 130c) are aligned with cam bars 110b and 1 10c, respectively, on upper surface portion 154. The staples of larger sizes (130a and 130d) are aligned with cam bars 1 10a and 1 10d, respectively, on lower surface portion 152. It is 8 envisioned in a preferred embodiment that the height difference "d1" between surface portions 152 and 154 of offset plane 151 is approximately twice the height difference "d2" between larger staples (130a and 130d) and smaller staples (130b and 130c). Other height differences are also contemplated. Preferably, the smaller staples are in the inside rows and the larger staples are in the outside rows. In this manner, the longer staples are provided on the outer rows where the tissue might be thicker as a result of clamping by the instrument jaws (anvil and cartridge) as some of the fluid of the tissue is squeezed out so that the tissue is compressed further at the center portions of the cartridge and anvil than at the lateral edges, thereby leaving thicker tissue at the edges. In this manner, the stapler is capable of limiting the flow of blood in the tissue immediately adjacent the cut tissue to effectuate hemostasis and wound closure, while maximizing blood flow in the surrounding tissue to facilitate healing. It should be appreciated that the offset planes of the present disclosure can also be used with other staplers, including, for example, other linear staples and endoscopic linear staplers, such as disclosed for example in Figure 5 described below. It is also contemplated that as an alternative to two surface heights of the cam member support 150 (or support 240 described below), more than two surface heights can be used. For instance, the offset planes can include surfaces of three different heights to provide advancement of cam members at three different levels. This can be used, for example, for applying three different size staples. A method of firing staples of different sizes is also provided. The method includes causing first and third cam members (bars) 1 10b, 1 10c to travel along a first plane and causing second and fourth cam members (bars) 1 10a, 1 10d, outboard of the first and third cam members 1 10b, 1 10c, to travel along a second plane, where the first plane and the second plane are offset from each other. The second plane is further from the anvil surface when the cartridge 19 and anvil are in position clamping tissue therebetween. As the cam bars 1 Oa-1 10d travel along the upper surface of cam member support 150, they contact respective pushers which then drive the respective staples out of the corresponding cartridge slot, through tissue clamped between the anvil and cartridge, and into anvil pockets for formation into B-shaped staples. This method applies staples of different lengths. For example, staples of shorter length would be applied to clamped tissue closer to the center of the jaws and staples of longer length would be applied to clamped tissue further from the center.

9 In a preferred embodiment, the raised (stepped) surfaces for supporting the cam bars cam can be formed on a plastic or other material insert in the bottom of channel 18 of the cartridge half section 12. The insert can be one piece formed with surfaces on different planes, e.g. by varying the thickness of the portions, or, alternatively, separate inserts to achieve the differing heights can be utilized. Figures 5 and 6 illustrate an alternate embodiment utilizing the concept of cam members on offset planes. Six caroming members 206a-206e are illustrated, attached together, with the two outer cam members on each side advanceable along one plane and the two middle cam members advanceable along a higher plane. More specifically, camming members 206a, 206b, 206e and 206f form the two outer rows of the cam bar assembly on each side of a longitudinal axis of the assembly. Cam members 206c and 206d are positioned in the middle (between the two outer rows) and configured for firing the two inner rows of staples. A cam member support 240 has an upper surface with an offset plane 241 such that it is stepped as shown to provide substantially parallel offset planes to offset the height of the two inner cam members 206c, 206d from the four outer cam members 206a, 206b, 206e, 206f. More specifically, cam member supporting member 240 is fixedly positioned within channel 230 of cartridge assembly 220 and its upper surface includes first and second lower surface portions 242, 244, and an intermediate upper surface portion 246 in between. The intermediate surface portion 246 has a raised surface such that it is higher, e.g. closer to the anvil assembly 214 when the instrument is clamped, than the outer lower surface portions 242, 244. The higher positioned cam members 206c, 206d slide along the raised intermediate surface portion 246. The cam bars slide distally to sequentially advance staple pushers in a direction substantially transverse to the movement of the cam members 206a-206f to fire longitudinal rows of staples contained in cartridge 227 through the tissue and against anvil member 225 to form the staples. In a preferred embodiment, the staples having legs of shorter length are fired by intermediate cam members 206c, 206d and the larger staples having legs of longer length are fired by the outer set of cam members 206a, 206b, 206e, and 206f. The outer surface portions 242 and 244 of offset plane 241 are lower, e.g. further from the anvil assembly 214 when the instrument is clamped, to accommodate the outer cam members 206a, 206b, 206e, 206f to fire staplers of longer length than the length of the staples in the inner rows.

10 This cam arrangement can be used with the endoscopic surgical stapler of Figure 5, which has an elongated tubular portion 212, an anvil assembly 214 pivotally mounted at a distal end portion of the elongated tubular portion 212 and a cartridge assembly 220. The anvil and cartridge assemblies 214, 220 are moved into approximation to clamp tissue therebetween. A handle 230 is squeezed to clamp the anvil and fire the staples in the manner disclosed in U.S. Patent Nos. 5,762,256 issued June 9, 1998 and 5,865,361 issued February 2, 1999, the entire contents of which are s incorporated herein by reference. In a preferred embodiment, staples of longer leg length are placed in the four outer rows and staples of shorter leg length are placed in the two inner rows. Preferably, the cam members are of substantially the same height, as are the pushers. Although described for fastener applying apparatus for firing staples formed by an anvil, the offset plane of this disclosure could also be used in fastener applying apparatus for firing two part fasteners. While the above description contains many specifics, these specifics should not be construed as limitations on the scope of the present disclosure, but merely as illustrations of various embodiments thereof. Therefore, the above description should not be construed as limiting, but merely as exemplifications of various embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the disclosure.

Claims (20)

1. A surgical fastener applying apparatus, comprising: a cartridge assembly including a plurality of fasteners, and a plurality of fastener pushers positioned beneath the fasteners, each of the fastener pushers defining an equivalent height; an anvil assembly movably connected to the cartridge assembly, the anvil assembly being configured and dimensioned to form the fasteners upon ejection from the cartridge assembly; first and second cam bars movable through the cartridge assembly to facilitate displacement of the fastener pushers and ejection of the fasteners from the cartridge assembly; and a supporting member fixedly positioned within the cartridge assembly beneath the first and second cam bars, the first cam bar being slidable along a first surface of the supporting member, and the second cam bar being slidable along a second surface of the supporting member, the first and second surfaces of the supporting member being positioned at different heights, wherein prior to firing of the surgical fastener applying apparatus, the fastener pushers are spaced apart from the first and second surfaces of the supporting member to facilitate engagement with the first and second cam bars.

2. The surgical fastener applying apparatus of claim 1, wherein the plurality of fasteners include a first set of fasteners each having legs defining a first length, and a second set of fasteners each having legs defining a second, greater length.

3. The surgical fastener applying apparatus of claim 2, wherein the first surface of the supporting member defines a first height, and the second surface of the supporting member defines a second height, the first height being greater than the second height.

4. The surgical fastener applying apparatus of claim 1, further including a third cam bar slidable along the first surface of the supporting member and a fourth cam bar slidable along the second surface of the supporting member such that the second cam bar and the fourth cam bar are positioned radially outward of the first cam bar and the third cam bar.

5. The surgical fastener applying apparatus of claim 4, wherein the cartridge assembly includes a longitudinal track extending therethrough configured and dimensioned to accommodate movement of a cutting member, the first and third cam bars being positioned on 12 opposite sides of the track, and the second and fourth cam bars being positioned on opposite sides of the track.

6. The surgical fastener applying apparatus of claim 1, wherein the first cam bar and the second cam bar define equivalent heights.

7. The surgical fastener applying apparatus of claim 1, wherein the first and second cam bars are configured and dimensioned such that the pushers are displaced transversely in relation to a direction of movement of the first and second cam bars.

8. The surgical fastener applying apparatus of claim 7, wherein the first cam bar defines a first camming surface and the second cam bar defines a second camming surface, the first camming surface extending transversely in relation to the first surface of the supporting member, and the second camming surface extending transversely in relation to the second surface of the supporting member.

9. The surgical fastener applying apparatus of claim 8, wherein the first and second cam bars each include a distally tapered configuration such that a distance defined between the first camming surface and the first surface of the supporting member decreases in a distal direction, and a distance defined between the second camming surface and the second surface of the supporting member decreases in a distal direction.

10. The surgical fastener applying apparatus of claim 1, wherein the first cam bar is connected to the second cam bar such that the first and second cam bars move as a single unit.

11. A cartridge assembly for use in a surgical fastener applying apparatus, the cartridge assembly comprising: a plurality of first fasteners each having legs defining a first length, and a plurality of second fasteners each having legs defining a second, greater length; a plurality of first fastener pushers positioned beneath the first fasteners, and a plurality of second fastener pushers positioned beneath the second fasteners, each of the first and second fastener pushers defining an equivalent height; first and second cam bars movable through the cartridge assembly to facilitate displacement of the fastener pushers and ejection of the fasteners from the cartridge assembly; and 13 a supporting member positioned within the cartridge assembly, the supporting member including a first surface supporting the first cam bar such that the first cam bar is slidable along the first surface into engagement with the plurality of first fastener pushers, and a second surface supporting the second cam bar such that the second cam bar is slidable along the second surface into engagement with the plurality of second fastener pushers, the first surface of the supporting member defining a first height, and the second surface of the supporting member defining a second height, the first height being greater than the second height.

12. The cartridge assembly of claim 1, further including a longitudinal track extending therethrough configured and dimensioned to accommodate movement of a cutting member.

13. The cartridge assembly of claim 12, wherein the plurality of first fasteners are arranged into first and second rows positioned on opposite sides of the longitudinal track, and the plurality of second fasteners are arranged into first and second rows positioned on opposite sides of the longitudinal track.

14. The cartridge assembly of claim 13, further including a third cam bar slidable along the first surface of the supporting member and a fourth cam bar slidable along the second surface of the supporting member such that the first cam bar and the third cam bar are positioned beneath the rows of first fasteners on opposite sides of the longitudinal track, and the second cam bar and the fourth cam bar are positioned beneath the rows of second fasteners on opposite sides of the longitudinal track.

15. The cartridge assembly of claim 11, wherein the first cam bar and the second cam bar define equivalent heights.

16. The cartridge assembly of claim 1, wherein the first and second cam bars are configured and dimensioned such that the pushers are displaced transversely in relation to a direction of movement of the first and second cam bars.

17. The cartridge assembly of claim 16, wherein the first cam bar defines a first camming surface and the second cam bar defines a second camming surface, the first camming surface extending transversely in relation to the first surface of the supporting member, and the second camming surface extending transversely in relation to the second surface of the supporting member. 14

18. The cartridge assembly of claim 17, wherein the first and second cam bars each include a distally tapered configuration such that a distance defined between the first camming surface and the first surface of the supporting member decreases in a distal direction, and a distance defined between the second camming surface and the second surface of the supporting member decreases in a distal direction.

19. The cartridge assembly of claim 11, wherein the first cam bar is connected to the second cam bar such that the first and second cam bars move as a single unit.

20. A cartridge assembly for use in a surgical fastener applying apparatus, the cartridge assembly comprising: a plurality of fasteners, and a plurality of fastener pushers positioned beneath the fasteners, each of the fastener pushers defining an equivalent height; first and second cam bars movable through the cartridge assembly to facilitate displacement of the fastener pushers and ejection of the fasteners from the cartridge assembly; and a supporting member fixedly positioned within the cartridge assembly beneath the first and second cam bars, the first cam bar being slidable along a first surface of the supporting member, and the second cam bar being slidable along a second surface of the supporting member, the first and second surfaces of the supporting member being positioned at different heights, wherein prior to firing of the surgical fastener applying apparatus, the fastener pushers are spaced apart from the first and second surfaces of the supporting member to facilitate engagement with the first and second cam bars. Covidien LP Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON