Abstract:
A surgical fastener applying apparatus comprising a cartridge body including a tissue contacting surface including a plurality of fastener retention slots arranged in a plurality of rows including at least an inner row and an outer row, a plurality of surgical fasteners disposed in the inner and outer rows and configured such that a plurality of fasteners disposed in the inner row have a first diameter that is less than a second diameter of a plurality of surgical fasteners disposed in the outer row, and an anvil having an inner row and an outer row of depressions for forming the fasteners. A plurality of pushers are operably associated with the plurality of surgical fasteners, the pushers configured to eject an associated surgical fastener towards the respective depression in the anvil such that upon formation of a corresponding surgical fastener, the surgical fasteners ejected from the inner row provide a greater compressive force to tissue than the surgical fasteners ejected from the outer row.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 61/044,652 filed Apr. 14, 2008, the entire contents of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to surgical fastener applying apparatus. More particularly, the present disclosure relates to a surgical fastener applying apparatus that includes a plurality of surgical fasteners configured to apply varying compressive forces to tissue, and methods of using the same. 
         [0004]    2. Background of the Related Art 
         [0005]    Commercially available surgical fastening apparatus are well known in the art, some of which are specifically adapted for use in various surgical procedures including, but not limited to, end-to-end anastomosis, circular end-to-end anastomosis, open gastrointestinal anastomosis, endoscopic gastrointestinal anastomosis, and transverse anastomosis. U.S. Pat. Nos. 5,915,616, 6,202,914, 5,865,361, and 5,964,394 each describe one or more suitable apparatus which may be employed while performing one of these procedures. 
         [0006]    In general, a surgical fastening apparatus will include an anvil that is approximated relative to a fastener cartridge during use or a fastener cartridge that is approximated relative to an anvil. The anvil includes depressions that are aligned with, and/or are in registration with slots defined in the cartridge, through which the fasteners will emerge, to effectuate formation. The fastener cartridge typically has one or more rows of fasteners disposed laterally or radially of a channel or knife slot that is configured to accommodate a knife, or other such cutting element, such that tissue can be simultaneously cut and joined together. Depending upon the particular surgical fastening apparatus, the rows of fasteners may be arranged in a linear or non-linear, e.g. circular, semi-circular, or otherwise arcuate configuration. 
         [0007]    Various types of surgical fasteners are well known in the art, including but not limited to unitary fasteners and two-part fasteners. Unitary fasteners generally include a pair of legs adapted to penetrate tissue and connected by a backspan from which they extend. In use, subsequent to formation, the unitary fasteners have a “B” configuration. Typically, the two-part fastener includes 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 use, the two-part fastener is pressed into the tissue so that the barbs penetrate the tissue and emerge from the other side where they are then locked into the retainer piece. 
         [0008]    During each of the aforementioned surgical procedures, the tissue is initially gripped or clamped between the cartridge and anvil such that individual fasteners can be ejected from the cartridge, through the slots, and forced through the clamped tissue. Thereafter, the fasteners are formed by driving them into the depressions formed on the anvil. 
         [0009]    A common concern in each of these 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 necessary to achieve hemostasis. To this end, conventional surgical fastening apparatus generally apply two or more rows of fasteners about the cut-line 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. 
         [0010]    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. 
         [0011]    Additionally, when tissue is clamped and compressed between the anvil and cartridge, some of the fluid of the tissue is squeezed out so 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. It would therefore be advantageous to provide staples which could better accommodate these resulting different tissue thicknesses. 
       SUMMARY 
       [0012]    The present disclosure provides in one aspect a surgical fastener applying apparatus comprising a cartridge body including a tissue contacting surface including a plurality of fastener retention slots arranged in a plurality of rows including at least an inner row and an outer row, a plurality of surgical fasteners disposed in the inner and outer rows and configured such that a plurality of fasteners disposed in the inner row have a first diameter that is less than a second diameter of a plurality of surgical fasteners disposed in the outer row, and an anvil having an inner row and an outer row of depressions for forming the fasteners, a plurality of pushers are operably associated with the plurality of surgical fasteners, the pushers configured to eject the surgical fasteners towards the respective depression in the anvil such that upon formation of a corresponding surgical fastener, the plurality of surgical fasteners ejected from the inner row provide a greater compressive force to tissue than the plurality of surgical fasteners ejected from the outer row. 
         [0013]    In one embodiment, the plurality of rows are spaced laterally on opposite sides of a channel that is located on the tissue contacting surface and configured to accommodate longitudinal movement of a knife operably associated with the cartridge body. 
         [0014]    Preferably, the surgical fasteners include two legs extending from a backspan extending therebetween. In a preferred embodiment, when formed the surgical fasteners include a generally “B” shape wherein a tissue compression space of the plurality of formed surgical fasteners ejected from the inner row is less than a tissue compression space of the plurality of formed surgical fasteners ejected from the middle row. 
         [0015]    In one embodiment, the two legs and the backspan include the same geometrical configuration such that the cross-sectional configuration of the surgical fastener is substantially uniform. In another embodiment, the two legs include the same geometrical configuration and the backspan includes a different geometrical configuration such that the cross-sectional configuration of the surgical fastener varies. 
         [0016]    In one embodiment, the plurality of retention slots are arranged in a plurality of rows including at least an inner row, a middle row, and an outer row wherein the plurality of the fasteners disposed in the inner row have a diameter that is less than a diameter of the plurality of the surgical fasteners disposed in the middle row, and the surgical fasteners disposed in the middle row have a diameter that is less than a plurality of the surgical fasteners disposed in the outer row. In this embodiment, a tissue compression space of the plurality of formed surgical fasteners ejected from the inner row is less than a tissue compression space of the plurality of formed surgical fasteners ejected from the middle and outer rows. 
         [0017]    In some embodiments, the cartridge body and anvil are pivotally attached. In other embodiments, at least one of the cartridge body and anvil is movable along a substantially linear path to move the cartridge and anvil into approximation. 
         [0018]    The present disclosure provides in another aspect a surgical fastener cartridge for use with a surgical fastener applying apparatus comprising a cartridge body including a tissue contacting surface and having a plurality of fastener retention slots arranged in a first row and a second row, the first row being closer to a central longitudinal axis of the cartridge body than the second row, a plurality of surgical fasteners disposed in a first row and a second row, the first fastener row being closer to a central longitudinal axis of the cartridge body than the second fastener row, wherein least one of the fasteners disposed in the first fastener row has a diameter that is less than a diameter of at least one of the surgical fasteners disposed in the second fastener row. 
         [0019]    Preferably, upon formation of the fasteners, a tissue compression space of the formed surgical fastener(s) ejected from the first row is less than a tissue compression spaced of the fastener(s) ejected from the second row. 
         [0020]    The cartridge can include a longitudinal channel configured to accommodate longitudinal movement of a knife, wherein the plurality of rows are spaced laterally on opposite sides of the channel. 
         [0021]    In a preferred embodiment, each of the surgical fasteners includes two legs connected by a backspan extending therebetween and when formed include a generally “B” shape. In some embodiments, the two legs and the backspan include the same geometrical configuration such that the cross-sectional configuration of the surgical fastener is substantially uniform. In other embodiments, the two legs include the same geometrical configuration and the backspan includes a different geometrical configuration such that the cross-sectional configuration of the surgical fastener varies. 
         [0022]    The cartridge can include a third row of fasteners being positioned further from the central longitudinal axis than the second row, wherein a least one of the fasteners in the third row has a diameter greater than a diameter of the at least one fastener in the second row. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    Various embodiments of the present disclosure are described hereinbelow with references to the drawings, wherein: 
           [0024]      FIG. 1  illustrates an exemplary surgical fastener applying apparatus for use with a surgical fastener cartridge that employs surgical fasteners in accordance with embodiments of the present disclosure; 
           [0025]      FIG. 2  illustrates another type of surgical fastener device that may employ an alternate embodiment of a surgical fastener cartridge in accordance with the present disclosure; 
           [0026]      FIG. 3  illustrates another type of surgical fastener instrument that may employ an alternate embodiment of surgical fastener cartridge in accordance with the present disclosure; 
           [0027]      FIG. 4  is a top perspective view of a surgical fastener cartridge shown in the distal end portion of the surgical fastener device depicted in  FIG. 1 ; 
           [0028]      FIG. 5A  is a side perspective view of the surgical fastener configured for use with the cartridge depicted in  FIG. 4  and having a first diameter and shown prior to formation; 
           [0029]      FIG. 5A-1  is a side perspective cutaway view taken along line segment A 1 -A 1  of the surgical fastener depicted in  FIG. 5A ; 
           [0030]      FIGS. 6A-6D  illustrate different surgical fasteners that include different backspan configurations in accordance with alternate embodiments of the present disclosure; 
           [0031]      FIG. 7  is a side perspective view of the surgical fastener depicted in  FIG. 5  shown subsequent to formation and within adjacent tissue segments; 
           [0032]      FIGS. 8A-8C  illustrate the surgical fastener depicted in  FIG. 7  shown having three different diameters and being shown prior to and subsequent to formation (in phantom); 
           [0033]      FIGS. 8A   -1 - 8 C -1  illustrate side perspective cutaway views taken along line segments A 1 -A 1  of the surgical fasteners depicted in  FIGS. 8A-8C , respectively; 
           [0034]      FIG. 9  is partial cross-sectional view taken along the line segment “ 9 - 9 ” in  FIG. 4  illustrating the surgical fastener cartridge loaded with the surgical fasteners depicted in  FIGS. 8A-8C ; and 
           [0035]      FIG. 10  illustrates another type of surgical fastener device that may employ an alternate embodiment of surgical fastener cartridge in accordance with the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0036]    Various exemplary embodiments of the presently disclosed surgical fastener cartridge, and method of manufacturing the same, will now be described in detail with reference to the drawings wherein like references numerals identify similar or identical elements. In the drawings and in the description which follows, the term “proximal” will refer to the end of the surgical fastener cartridge that is closer to the operator during use, while the term “distal” will refer to the end of the fastener cartridge that is further from the operator, as is traditional and conventional in the art. In addition, the term “surgical fastener” should be understood to include any substantially rigid structure formed of a biocompatible material that is suitable for the intended purpose of joining tissue together, including but not being limited to surgical staples, clips, and the like. 
         [0037]    The present disclosure provides a surgical fastener cartridge adapted to house a plurality of surgical fasteners providing varying degrees of compression force to stapled tissue occupied therein such that an effective hemostatic effect at or near the cut-line may be achieved. To this end, the surgical fasteners are configured such that the surgical fasteners deployed closer to the cut line produce a greater compression force to stapled tissue than the surgical fasteners deployed further from the cut line. 
         [0038]    With reference to  FIG. 1 , a surgical fastener applying apparatus  1000  that employs a surgical fastener cartridge  100  is illustrated. Surgical fastener applying apparatus  1000  is used to sequentially apply a plurality of surgical fasteners to a patient&#39;s tissue. Surgical fastener apparatus  1000  may be configured for use, subsequent sterilization and reuse, or may be configured for single use. Surgical fastener applying apparatus  1000  includes a handle  1002 , an elongated shaft or endoscopic portion  1004  extending distally therefrom, and an operative tool assembly  1006  coupled to a distal end  1008  of the elongated shaft  1004 . In general, operative tool  1006  is adapted to clamp, sequentially fasten together, and sever adjacent tissue segments along a cut-line. Operative tool  1006  includes a pair of opposed jaws  1012 ,  1010  pivotally coupled to one another and respectively including an anvil member  1014  that is approximated relative to cartridge  100  during use. The anvil includes depressions that are aligned with, and/or are in registration with slots  126  defined in the cartridge  100 , through which the fasteners  130  will emerge, to effectuate formation. For a more detailed discussion of the approximation and firing of surgical fastener applying apparatus  1000 , reference is made to commonly owned U.S. Pat. No. 5,865,361 currently assigned to Tyco Healthcare Group LP, the entire contents of which is incorporated herein by reference. In some embodiments, the cartridge and/or anvil is removable and replaceable. 
         [0039]    While surgical fastener applying apparatus  1000  is depicted as an apparatus suitable for use in laparoscopic procedures for performing surgical anastomotic fastening of tissue, those skilled in the art will appreciate that cartridge  100  may be adapted for use with any surgical instrument suitable for the intended purposes described herein. For example, cartridge  100  may be adapted for use with an end-to-end anastomosis device  2000 , as seen in  FIG. 2 , wherein the fasteners are arranged in substantially annular rows and/or a surgical stapling instrument  3000 , as seen in  FIG. 3 , for use during an open gastro-intestinal anastomotic stapling procedure wherein the fasteners are arranged in substantially linear rows, or, for example, any of the surgical fastener applying apparatus disclosed in U.S. Pat. Nos. 6,045,560; 5,964,394; 5,894,979; 5,878,937; 5,915,616; 5,836,503; 5,865,361; 5,862,972; 5,817,109; 5,797,538; and 5,782,396, which are each incorporated by reference herein in their entirety. The cartridge in some embodiments is removable and replaceable with another loaded cartridge. 
         [0040]    For the purposes of brevity, the structural and operational features of cartridge  100  will be described in terms of use with the surgical fastener applying apparatus  1000 . 
         [0041]    With reference to  FIG. 4 , cartridge  100  of assembly  1006  is shown. Cartridge  100  extends along a longitudinal axis “A-A” and includes a cartridge body  112  with a pair of side walls  114 ,  116 , a bottom wall  118 , and a top wall  120 . The top wall  120  includes a channel or knife slot  122  that is configured to accommodate longitudinal movement of a knife (not shown), or other suitable cutting element, such that stapled tissue may be severed along a cut-line. The top wall  120  further includes a tissue engaging surface  124  (e.g., for maintaining the position of the tissue to be cut) and a plurality of fastener retention slots  126  arranged into a plurality of rows  128  that extend substantially the length of the cartridge  100 . As shown in  FIG. 4 , the fastener retention slots  126  are arranged into a pair of first (inner) rows  128   A  that are spaced laterally from the knife slot  122  and on opposite sides thereof, a pair of second (middle) rows  128   B  that are spaced laterally from the pair of first rows  128   A  and on opposite sides of the knife slot  122 , and a pair of third (outer) rows  128   C  that are spaced laterally (outboard) from the pair of second rows  128   B  and on opposite sides of knife slot  122 . While the cartridge  100  is depicted as including pairs of first, second, and third rows  128   A ,  128   B ,  128   C , respectively, it is within the purview of the present disclosure to have more or fewer rows of the fastener retention slots  126  (and fasteners) disposed on cartridge  100 . Additionally, rows  128  may extend radially from the cutting element; such is the case when the fastening cartridge is employed with the surgical fastening device depicted in  FIG. 2 . 
         [0042]    Each of the fastener retention slots  126  is configured to receive one of a plurality of surgical fasteners  130  and pushers  150  therein such that the surgical fasteners  130  are deployed in rows (e.g., inner, middle, and outer rows) on opposite sides of the cut-line created in the tissue during fastening, as shown in  FIG. 9 . 
         [0043]    For a more detailed description of the functional and structural features of cartridge  100 , reference is made to commonly owned U.S. Pat. No. 7,070,083 the entire contents of which are incorporated by reference herein. 
         [0044]    With reference now to  FIGS. 5A ,  5   A-1 , and  6 A- 6 D, cartridge  100  may loaded with one or more varieties of surgical fastener, represented generally as surgical fastener  130 . Surgical fastener  130  of cartridge  100  is configured such that the surgical fastener  130  deployed closer to the cut line provides a greater compressive force to the stapled tissue than the surgical fastener  130  deployed further from the cut line. To this end, surgical fastener  130  includes two legs  132  extending from a backspan  134  extending therebetween. The thickness of the backspan  134  and the legs  132  can be varied such that the surgical fastener  130  closer to the cut line provides a greater compressive force to stapled tissue occupied therein than the surgical fastener  130  further from the cut line. The thickness of the backspan  134  and the legs  132  may also be varied to fasten adjacent tissue segments “T 1 ”, “T 2 ” of varying thickness. 
         [0045]    The legs  132  and the backspan  134  may define a cross-section having any suitable geometric configuration, including but not limited to rectangular, oval, square, triangular, and trapezoidal. The legs  132  and the backspan  134  may exhibit the same geometrical configuration such that the cross-sectional configuration of the surgical fastener  130  is substantially uniform, as shown in  FIG. 5A , or, alternatively, the legs  132  and the backspan  134  may exhibit different geometrical configurations, e.g., the legs  132  may exhibit a rectangular cross-section and the backspan  34  may exhibit an oval cross-section, as shown for example in  FIGS. 6A-6D , discussed in more detail below. Backspan  134  and/or legs  132  may be formed by any suitable means known in the art including but not limited to welding, braising, coining, casting, molding, overmolding and so on. Additionally, backspan  134  and/or legs  132  may be treated by way of annealing, cold working, heat treating, and so on. This may provide increased burst strength to the surgical fastener. Moreover, backspan may include different configurations of blocking and/or retainer material, tube, sleeve, collar, and/or grommet. 
         [0046]    As seen in  FIG. 5A , prior to the formation of surgical fastener  130 , legs  132  extend from the backspan  134  such that they are substantially parallel. Alternatively, the legs  132  may converge or diverge from the backspan. The present disclosure contemplates that the surgical fastener  130  may also be configured as a directionally biased staple, such as those described in commonly owned U.S. Pat. No. 7,398,907, the entire contents of which are incorporated by reference herein. 
         [0047]    Each of the legs  132  terminates in a penetrating end  136  that is configured to penetrate tissue (tissue segments “T 1 ”, “T 2 ” for example) and/or other suitable material (blocking and/or retainer material for example). The penetrating ends  136  of legs  132  can be tapered to facilitate the penetration of tissue segments “T 1 ”, “T 2 ”, or alternatively, the penetrating ends  136  may not include a taper. In various embodiments, penetrating ends  136  may define a conical or flat surface, as described in co-pending U.S. patent application Ser. No. 11/444,761, filed Apr. 13, 2003, the entire contents of which are incorporated by reference herein. In some embodiments, one or both of legs  132  may be barbed. Having legs  132  configured in such a manner may facilitate maintaining the surgical fastener  130  in a fixed position within the tissue and/or blocking material. 
         [0048]    Turning now to  FIG. 7 , surgical fastener  130  is shown subsequent to formation. Surgical fastener  130  is configured to provide a compression force to stapled tissue occupied therein. To this end, legs  132  cooperate with backspan  134  to maintain adjacent tissue segments “T 1 ”, “T 2 ” in approximation and apply a compressive force “F” thereto. The compressive force “F” applies pressure to the tissue segments “T 1 ”, “T 2 ”, thereby restricting the flow of blood through the tissue surrounding the surgical fastener  130  and facilitating hemostasis. The linear configuration of the backspan  134  may limit the amount of pressure that can be applied to the tissue segments “T 1 ”, “T 2 ” such that the flow of blood through the tissue is not completely restricted. When formed, the surgical fastener  130  has a generally “B” shape with an overall height “H F ” (measured from the outermost surface of the backspan  134  to the outermost curve of the legs  132 ) and a tissue compression space  140 . 
         [0049]    With reference to  FIGS. 8A-8C , and FIGS.  8 A- 1 - 8 C- 1 , respectively, surgical fastener  130  will be described in terms of surgical fasteners  130   A,    130   B,  and  130   C.  Surgical fasteners  130   A,    130   B,  and  130   C  are respectively shown in their initial (unformed) and formed conditions (in phantom). Surgical fasteners  130   A ,  130   B ,  130   C , are substantially similar to each other but for their respective diameters. The overall heights of the surgical fasteners  130   A ,  130   B ,  130   C , in the unformed condition (measured from the penetrating tip of the legs to the outermost surface of the backspan) are shown as being substantially equal. The respective dimensions “D 1 ”, “D 2 ”, and/or “D 3 ” of surgical fasteners  130   A,    130   B  and  130   C,  may be altered, which, in turn, will alter the dimensions of the compression spaces  140   A ,  140   B,    140   C  occupied by stapled tissue segments “T 1 ”, “T 2 ” when the respective surgical fasteners  130   A ,  130   B,    130   C  are in their formed conditions. One reason being, as the diameter of a surgical fastener increases so to does the driving force required to buckle them and form against the corresponding portion of the anvil. The driving force is provided by a pusher and sled configuration operatively connected to the cartridge  100 . Because the pusher and sled are slightly flexible, they tend to “give” or deflect during formation of the surgical fasteners. Thus, surgical fasteners having larger diameters (e.g., surgical fasteners  130   B  and/or  130   C ) will cause the pusher and sled to deflect more than surgical fasteners having smaller diameters (e.g., surgical fastener  130   A ). As a result, surgical fasteners having larger diameters form a “B” shape with a larger tissue compression space  140  and surgical fasteners having smaller diameters form a “B” shape with a smaller tissue compression space  140 . By altering the respective dimensions of “D 1 ”, “D 2 ”, and/or “D 3 ” any desired level of hemostasis and blood flow in the stapled tissue segments “T 1 ”, “T 2 ” may be effectuated. Other various attributes of the tissue (e.g., thickness or the presence of scar tissue) may increase or diminish the level of hemostasis and blood flow in the stapled tissue segments. 
         [0050]    Surgical fastener  130   C  has a diameter “D 3 ”. When the surgical fastener  130   C  is formed (phantomly shown in  FIG. 8C ) within tissue segments “T 1 ”, “T 2 ”, the backspan  134   C  cooperates with the legs  132  of the surgical fastener  130   C  to form tissue compression space  140   C  ( FIG. 8C ). As noted, the surgical fasteners deployed further from the cut line tend to deflect the pusher and sled more than the surgical fasteners deployed closer to the cut-line, which, in turn, provides the largest compression zone. Compression space or zone  140   C  provides minimal blood flow restriction when the tissue segments are stapled together. 
         [0051]    Surgical fastener  130   B  has a diameter “D 2 ”, less than the diameter “D 3 ” of fastener  130   C . When the surgical fastener  130   B  is formed (phantomly shown in  FIG. 8B ) within tissue segments “T 1 ”, “T 2 ”, the backspan  134   B  cooperates with the legs  132  of the surgical fastener  130   B  to form tissue compression space  140   B  ( FIG. 8B ). Here, because the diameter of surgical fastener  130   B  is less than the diameter of surgical fastener  130   C , the pusher and sled will deflect less than that as described above with regard to surgical fastener  130   C . This results in formation of a tighter “B” shape with the resultant compression space  140   B  less than the compression space  140   C  of fastener  130   C . Accordingly, because the pressure exerted on the tissue segments “T 1 ”, “T 2 ” by surgical fastener  130   B  is greater than the pressure exerted on the tissue segments “T 1 ”, “T 2 ” by surgical fastener  130   C , the blood flow through the tissue surrounding surgical fastener  130   B  will be less (more restricted) than the blood flow through the tissue surrounding surgical fastener  130   C , thereby further facilitating hemostasis. However, because blood flow is not completely restricted through tissue compression space  140   B,  unnecessary necrosis of the stapled tissue may be prevented and/or impeded. 
         [0052]    Surgical fastener  130   A  has a diameter “D 1 ”, less than the diameter “D 2 ” of fastener  130   B . When the surgical fastener  130   A  is formed (phantomly shown in  FIG. 8A ) within tissue segments “T 1 ”, “T 2 ”, the backspan  134   A  cooperates with the legs  132  of the surgical fastener  130   A  to form tissue compression space  140   A  ( FIG. 8A ). Here, because the diameter of surgical fastener  130   A  is less than the diameters of surgical fasteners  130   B  and  130   C , the pusher and sled will deflect less than that as described above with regard to surgical fasteners  130   B  and  130   C . This results in formation of an even tighter “B” shape with the resultant compression space  140   A  less than the compression space  140   B  of fastener  130   B . Accordingly, because the pressure exerted on the tissue segments “T 1 ”, “T 2 ” by surgical fastener  130   A  is greater than the pressure exerted on the tissue segments “T 1 ”, “T 2 ” by surgical fasteners  130   B ,  130   C,  the blood flow through the tissue surrounding surgical fastener  130   A  will be less (more restricted) than the blood flow through the tissue surrounding surgical fasteners  130   B,    130   C , thereby further facilitating hemostasis. Because blood flow is substantially, if not completely restricted through tissue compression space  140   A , this results in facilitating and effectuating hemostasis. 
         [0053]      FIG. 9  illustrates the surgical fasteners  130   A ,  130   B,  and  130   C  loaded within the cartridge body  112  shown in  FIGS. 1 and 4 . The surgical fasteners  130   A ,  130   B , and  130   C  are arranged to define a pair of inner, middle, and outer rows  128   A ,  128   B,  and  128   C , respectively, of fastener retention slots  126  formed in the top wall  120 . The pair of inner, middle, and outer rows  128   A ,  128   B,  and  128   C , respectively, are each spaced laterally from the knife slot  122 , on opposite sides thereof, such that the surgical fasteners  130   A ,  130   B,  and  130   C  will be deployed on opposite sides of the cut-line (not shown) created in the tissue upon fastening. That is, the fasteners  130   A  with the smallest diameter provide a greater compressive force in the illustrated embodiment are provided in the inner rows closer to the cut line. The fasteners  130   B , due to their larger diameter, are provided on the outer rows where the tissue might be thicker as a result of clamping by the instrument jaws (anvil and cartridge). If a third row of fasteners  130   C  is used in this embodiment, then the fasteners of  FIG. 8C  with the largest diameter (largest compression space) would preferably be placed on the outermost row furthest from the cut line. It should be appreciated, however, that the fasteners can be placed on other rows than the foregoing. Also, while the inner, middle, and outer rows  128   A ,  128   B,  and  128   C , respectively, are shown as including the surgical fasteners  130   A ,  130   B ,  130   C , respectively, the present disclosure contemplates the inclusion of the surgical fasteners  130   A ,  130   B , and  130   C , in other rows or arrangement of any of the surgical fasteners  130   A ,  130   B , and  130   C , disclosed herein, either exclusively, such that only a single surgical fastener, e.g., surgical fastener  130 , is present in a particular row, or in combination, such that a variety of surgical fasteners, e.g., surgical fasteners  130   A ,  130   B , and  130   C , are present in one or more of the rows. 
         [0054]    In one particular embodiment, the outer rows  128   C , intermediate rows  128   B , and inner rows  128   A  are comprised solely of surgical fasteners  130   C ,  130   B , and  130   A , respectively such that the flow of blood through the tissue immediately surrounding the cut-line (not shown) is substantially, if not completely, restricted by the inner row  128   A  of surgical fasteners  130   A , whereas the flow of blood through the tissue surrounding the intermediate and outer rows  128   B ,  128   C  is less restricted by surgical fasteners  130   B ,  130   C , respectively. Accordingly, the flow of blood is minimized in the tissue immediately adjacent the cut-line and is increased gradually as the lateral distance from the cut-line is also increased. Also by this arrangement, the fasteners with the largest diameter (fasteners  130   C ), are furthest from the cut line where the tissue is generally compressed to the lesser extent and the fasteners with the smaller diameter are positioned in the inner rows where the tissue is compressed to the greater extent. It should be appreciated that the diameters of the fasteners could be varied to accommodate tissue of different thicknesses and to control tissue compression by the fasteners. 
         [0055]    In the embodiment of  FIGS. 5 and 7 , the backspan and legs are shown having a uniform diameter. It should be appreciated that the diameter of the legs and backspan, or portions thereof, can vary within the fastener. Examples of varying size backspan are shown in  FIGS. 6A-6B . In the embodiment of  FIG. 6A , the backspan is enlarged with respect to the legs and is an integral element  234  in which the fastener legs  232  are embedded. In  FIG. 6C , the backspan is  334  is integral with the fastener legs  332 . In the embodiments of  FIGS. 6B and 6D , a separate backspan material is attached to the fastener  430 ,  530 , respectively, with backspan  434  of  FIG. 6B  including a cylindrical collar  435  encircling the backspan portion  431  of the fastener  430  and the backspan  534  of fastener  530  of  FIG. 6D  encompassing the backspan portion  531  of the fastener and a portion of the fastener legs  532 . The backspan material of  FIGS. 6B and 6D  can be composed of thermoplastic overmolded on the staple wire, by way of example. Varying the thickness or height of these backspans or backspan materials can vary the compression force of the formed staple by varying the distance between the curved legs and inner portion of the backspan. This variation can be provided in addition to the varying diameters of the fastener to accommodate varying tissue thicknesses.  FIG. 6B  illustrates this varying backspan by showing in phantom a collar of larger diameter (D 2  compared to D 1 ) to decrease the compression area. Other backspan shapes and attachments to achieve the various compression forces are also contemplated. 
         [0056]    From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, the surgical fasteners described herein above may be formed from a variety of surgically acceptable materials including titanium, plastics, bio-absorbable materials, etc. Additionally, any of the aforementioned surgical fasteners may be treated, chemically or otherwise, prior to being loaded into cartridge  100 . 
         [0057]    It is also contemplated that the backspan  134  of the surgical fastener  130  may include one or more pockets (not explicitly shown) that are positioned to engage the legs  132  during formation of the surgical fastener  130  and configured to redirect the legs  132  such that they are coiled toward the backspan  134 , as discussed in commonly owned U.S. patent application Ser. No. 11/444,664, filed Jun. 1, 2006, the entire contents of which are incorporated by reference herein. 
         [0058]    The surgical fastening cartridge  100  and anvil may also be employed with a surgical fastener applying apparatus  4000  ( FIG. 10 ) that is used to simultaneously deploy a plurality of surgical fasteners, arranged in substantially linear rows transverse to a longitudinal axis of the apparatus, into either side of a target section of tissue (not explicitly shown). Here, a scalpel or other such cutting element may be used to remove the target section of tissue, or a built in knife could be provided which could be advanced upon advancement (firing) of the fasteners. The fasteners  130  would be supported within the cartridge or fastener supporting portion  4002 . Approximation of the cartridge and anvil supporting portion  4003 , e.g. linear movement of the fastener supporting portion  4002  toward the anvil supporting portion  4003 , via movement of lever  4006  clamps tissue therebetween. The fasteners can then be advanced into the anvil pockets as described above upon squeezing of handle  4007 , providing varying compressive forces on the tissue due to the varying diameters. Further details regarding the use and function of surgical fastener applying apparatus  4000  may be obtained through reference to U.S. Pat. Nos. 7,070,083 and 5,964,394 the entire contents of which are incorporated herein by reference. In an alternate embodiment, the apparatus  4000  could include a cutting element as in the other cartridges disclosed herein. Such staplers can also include other mechanisms for approximating the anvil and cartridge and firing the fasteners. The cartridge and anvil can also be used with other apparatus for simultaneously deploying a substantially linear row of fasteners, such as U.S. Pat. No. 7,407,076, the entire contents of which is incorporated herein by reference. 
         [0059]    As noted above, the surgical fastening cartridge  100  may also be employed with a surgical fastener applying apparatus  3000  ( FIG. 3 ) that is used to sequentially deploy a plurality of surgical fasteners arranged in substantially linear rows substantially aligned with the longitudinal axis of the apparatus, into either side of a target section of tissue (not explicitly shown). Here, a knife is advanced with the firing of the fasteners. The fasteners  130  would be supported within the cartridge or fastener supporting portion  3002 . The instrument halves  3001  and  3003  are clamped together to approximate the cartridge and anvil, and movement of firing knob  3005  sequentially fires the fasteners into contact with the anvil pockets of the anvil portion  3004 , providing varying compressive forces on the tissue due to the varying diameters. 
         [0060]    As noted above, the surgical fastening cartridge  100  may also be employed with a surgical fastener applying apparatus  2000  ( FIG. 2 ) that is used to simultaneously deploy a plurality of surgical fasteners arranged in substantially annular rows, into either side of a target section of tissue (not explicitly shown). Here, a knife is advanced with the firing of the fasteners. The fasteners  130  would be supported within the cartridge or fastener supporting portion  2002  Approximation of the cartridge  2002  and anvil  2004 , e.g. retraction of the anvil  2004  by rotation of approximation knob (wing nut)  2005  clamps tissue between the anvil  2004  and cartridge  2002 . The fasteners can then be advanced into the contact with the anvil pockets by squeezing of handles  2007 , providing varying compressive forces on the tissue due to the varying diameters 
         [0061]    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 exemplary of various embodiments.