Abstract:
A surgical buttress-dispensing assembly configured for releasably engaging a surgical stapling device. The surgical buttress-dispensing assembly comprises an one-piece cartridge for receiving and engaging therein an elongate buttress strip, and a carrier configured to slidingly receive, engage, and discharge the cartridge. The cartridge comprises a cylindrical end portion from which extends a pair of opposed elongate semi-circular sleeves. The cylindrical end portion is configured to slidingly received therethrough the closed closed jaws of a surgical stapler. The semi-circular sleeves are configured such that each sleeve slidingly communicates and cooperates with one of the stapler&#39;s jaws. The elongate edges of the sleeves are configured to engage and retain therewith the elongate edges of a surgical buttress strip. The carrier is engaged with a cartridge having a buttress strip installed onto the opposed sleeves, and is manipulated to slide and mount the cartridge onto the jaws of a surgical stapler.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from our prior provisional applications Ser. Nos. 60/794,130 filed Apr. 24, 2006; 60/815,848 filed Jun. 23, 2006; and 60/879,366 filed Jan. 9, 2007. 
     
     FIELD OF THE INVENTION 
       [0002]    This invention relates to surgical buttress assemblies. More particularly, this invention relates to surgical buttress assemblies configured for cooperating with surgical stapler devices. 
       BACKGROUND OF THE INVENTION 
       [0003]    Surgical stapler devices and systems are now commonly employed in most surgical procedures due to their ease-of-use, rapid action, and provision of uniformly spaced-apart sutures. There are three main types of surgical stapler devices currently in common use: (1) endoscopic stapler devices which are sized and configured for cooperation with trocar devices during laparoscopic surgical procedures, (2) linear stapler devices that are sized and configured for opened-body procedures, and (3) circular stapler devices configured for conjoining surgically-separated cylindrical organs and tissues such as small intestines and colons. Such surgical stapler devices usually have an ergonomically shaped, ambidextrous handle containing a plurality of levers and typically comprise a long shaft at the end of which is provided a fixed jaw onto which is placed a cartridge containing at least two rows of a plurality of opposed surgical staples. The fixed jaw is interconnected at a fulcrum point with a moveable jaw fitted with an anvil component. A knife component for surgically separating tissues is usually provided interposed the rows of surgical staples. Manipulation of a first actuating lever attached to the handle of the stapler, compresses the tissue to be surgically separated, after which manipulation of a second lever: (a) fires the staples contained in the cartridge against the anvil thereby surgically engaging a separate tissue section with each row of staples, then (b) actuates a knife to surgically separate the tissue sandwiched between the two rows of engaged staples. Although such surgical stapler devices and stapling systems have significantly simplified surgical procedures, a significant problem is the imposition of stretching tension and stress on a tissue section that has been engaged by a row of surgical staples. Such stretching tensions and stresses quite often result in the tissue tearing about the staple engagement points and in severe instances, may result in the conjoined tissue separating causing post-operative bleeding and other complications requiring an other episode of surgical intervention. Consequently, there have been numerous devices and methods developed for reinforcing and/or buttressing surgical stapled sutures, as exemplified by: 
         [0004]    U.S. Pat. No. 6,939,358 which discloses a self-adherent synthetic biocompatible material which is attached to an operational surface of a surgical stapler by an application card provided with pre-cut tear lines that allow the material to be applied held in place on the stapler while the surgical procedure is carried out, and then to buttress the surgical suture lines; 
         [0005]    U.S. Pat. No. 5,810,855 which discloses a synthetic sleeve known as “SEAMGUARD®” (registered trade mark of W.L. Gore &amp; Associates Inc., Newark, Del., USA) which surrounds the stapler jaws provided at the end of the operational arm. After the staples have been fired and the conjoined tissue sections severed and reinforced by the SEAMGUARD® material, the excess material must be trimmed from the tissue sections and removed from the trocar before completing the surgical procedure; 
         [0006]    U.S. Pat. No. 5,810,855 which discloses a manipulated bovine pericardium strip known PERI-STRIPS DRY® (registered trade mark of Bio-Vascular Inc., St. Paul, Minn., USA) for securing to the jaws of a surgical stapler with a biocompatible glue; 
         [0007]    U.S. Pat. No. 6,656,193 which discloses several buttress devices configured to engage surgical stapler jaw ends. These devices are configured for mechanical retention to the jaws until the stapling procedure has been completed; 
         [0008]    U.S. Pat. No. 6,656,193 which discloses a pericardial buttress strip provided with at least one end having an aperture for engaging at least on jaw end of the stapler; and 
         [0009]    U.S. Pat. No. 6,704,210 which discloses a sealing film strip attached to a surgical stapler by passing a jaw of the stapler though openings formed in the ends of the strip. 
         [0010]    Current state-of-the art surgical stapler devices typically require complex loading and securing processes to fix and maintain the buttress materials in place until the staples are fired. Consequently, there are numerous problems associated with the prior art buttress strips with such stapler devices. For example, buttress strips concurrently secured with adhesive materials to the cartridge on the fixed jaw and the anvil on the articulating jaw the stapler, require both surfaces to be completely dry in order to provide the desired orientation during staple firing. If those surfaces are not dry during the staple firing process, the buttress material will slide around on the cartridge and anvil while the user approximates the device around the tissue to be conjoined and severed. The jaws of multiple-fire staplers, i.e., stapler devices that are configured to conjoin and staple together several tissue sections in sequence typically become wet as a result of contact with tissues during the first staple firing process, thereby causing loosening the remaining buttress strips on the jaw surfaces resulting in misalignment during the second and third staple firings. Quite often, sutured tissue sections resulting from second and third staple firings are provided with partial buttressing or may not have any buttressing materials reinforcing the suture line. Another problem with the current prior art buttress materials is that the adhesive strength of the biocompatible glues used to fix the strips to the jaws is insufficient to maintain the strips in place on the jaws as the stapler is manipulated through the trocar and about the tissues to be surgically conjoined and severed. This results in considerable inconvenience to the operator since the dislodged strips need to be retrieved and re-affixed to the stapler prior to firing the staples. 
         [0011]    Another method of attaching buttress materials to surgical stapler jaws is the use of suture threads to tie the strips to the stapler jaws; however this process is time consuming and the requisite delicate handling and precise manipulation of the stapler and buttress strips is a distraction during a surgical procedure. Another prior art method for securing buttress materials onto surgical staplers involves the use of retainer appliances configured for cooperating with the stapler jaws. However, such appliances typically add significant girth to the overall profile of the jaw portion of the stapler shaft which requires the use of larger diameter trocars to facilitate entry of the stapler device into a body cavity wherein the endoscopic surgical procedure is to be performed. 
         [0012]    In order to minimize the size of the hole in the abdomen wall required to insert the trocar perform the endoscopic surgery and to minimize the leakage of gas and/or fluid through the trocar, the inner and outer diameters of the trocar must be configured as small as possible, while providing sufficient room for passage of the stapler device through the passageway into the body cavity. Only nominal clearance is provided for passage of the stapler device through the trocar. Therefore, the addition of buttress materials in the form of sleeves surrounding the jaws of the stapler increases the overall diameter of the stapler such that it can no longer pass through a preferred small-diameter trocar. Physicians are reluctant to use larger trocars, which provide more clearance for the above stated reasons. Ideally the buttressing material can be added to the stapler with little or no increase in diameter of the stapler such that the stapler can pass easily through a standard trocar intended for use with that stapler. 
         [0013]    Surgical circular staplers have been developed and are commonly used for surgical joining of separate hollow organ sections into one elongate member, e.g., intestinal tissues. A buttress is commonly placed between the stapling surface and the native hollow sections that are to be joined after which one or more rows of staples are fired to sealingly connect the organ sections while simulataneously cutting out the centre of the buttress. A serious problem often encountered with these types of procedures is leakage from anastomoses resulting in loss of luminal contents from the organ tissues into the surrounding body cavities resulting in life-threatening infections. U.S. Pat. No. 6,656,193 discloses a hot melt adhesive system configured to releasably engage pericardium strips mounted onto removable perforated buttress rings which cooperate with the anvil head sections of surgical circular staplers. However, the process of fixing the buttress materials onto the buttress rings, and then engaging the loaded buttress rings with the anvil components is complicated and requires precisely controlled dexterity to ensure proper alignment of the buttress materials in the circular staplers. It is essential that the surfaces of the buttress materials and buttress rings are completely dry in order to ensure good adhesion during loading of the anvil section, and then during insertion and maneuvering of the surgical stapler into and within the body cavity. The buttress materials are often dislodged from the buttress rings during the insertion and manipulation of the stapler with the consequence that the stapler must be removed from the body cavity, the anvil section disassembled to reposition and re-adhere the buttress material before proceeding. Furthermore, it is difficult to center and maintain the buttress material in a concentric orientation with the stapler with the result that the buttress materials do not completely cover the staple line sections resulting in stapled tissue sections that are not buttressed—these are the sections predisposed to leakage of luminal materials passing therethrough. 
         [0014]    Therefore, a need still exists for a method of easily attaching a buttress material to the stapler jaws that does not increase the outer diameter of the stapler so that it will not pass through the trocar, and finally that will secure the material to the stapler jaws even when the user approximates around the tissue. 
       SUMMARY OF THE INVENTION 
       [0015]    The exemplary embodiments of the present invention, at least in preferred forms, are directed to surgical buttress assemblies for releasably engaging surgical stapling devices configured to slidingly communicate and cooperate with trocars. 
         [0016]    According to one embodiment of the present invention, there are provided surgical buttress assemblies comprising a cartridge configured for receiving and engaging therein an elongate buttress strip, and a carrier configured for demountably engaging said cartridge for delivery and installation onto the jaws of a surgical stapler. 
         [0017]    According to one aspect, the cartridge comprises a cylindrical base portion from which extend two elongate opposing semi-circular sleeves. The sleeves are configured to slidingly communicate and cooperate with the outer surfaces of the jaws of a surgical stapler. 
         [0018]    According to another aspect, the elongate side edges of each semi-circular sleeve are provided with gripping means for engaging the elongate side edges of buttress strips. Suitable gripping means are exemplified by serrated edges, resilient fingers, Velcro® strips (Velcro is a registered trademark of Velcro Industries B.V.), and forward-extending tabs. Forward-facing tabs comprising the gripping means, may be optionally provided with pointed and/or sharpened leading edges to facilitate piercing and penetration of the tabs into the edges of the buttress strips. 
         [0019]    According to a yet another aspect, the cartridge comprises a cylindrical base portion from which extend two opposing fingers. Each finger comprises an elongate arched member from which opposing channels extend upward and outward along the longitudinal axis. Each channel is configured for receiving and engaging therein a portion of an elongate buttress strip. It is optional to provide each channel with a gripping means for engaging and retaining the elongate edges of a buttress strip. The jaws of a surgical stapler are inserted through the cylindrical base portion after which one of the elongate arched fingers slidingly communicates with the outer surface of one jaw, while the other elongate arched finger slidlingly communicates with the outer surface of the other jaw. A buttress guide is optionally provided for engaging a portion of the buttress strip interposed the two fingers during installation of the cartridge onto the surgical stapler. 
         [0020]    According to another aspect, the cartridge comprises an elongate arched finger from which opposing channels extend upward and outward along the longitudinal axis. Each channel is configured for receiving and engaging therein a portion of an elongate buttress strip. It is optional to provide each channel with a gripping means for engaging and retaining the elongate edges of a buttress strip. A first such cartridge is engaged with one end of an elongate buttress strip, and a second such cartridge is engaged with the other end of the buttress strip. The first cartridge is then slid over one jaw of a surgical stapler with the jaw interposed the cartridge and the buttress strip. The second cartridge is slid over the other jaw of the surgical stapler with the jaw interposed the cartridge and the buttress strip. A buttress guide is optionally provided for engaging a portion of the buttress strip interposed the two cartridges during installation onto the surgical stapler. 
         [0021]    According to yet a further preferred embodiment of the present invention, there is provided a surgical buttress apparatus for cooperating with a surgical circular stapler. The apparatus comprises a biocompatible buttress material, a buttress support disc configured for slidingly cooperating with the anvil head assembly of a circular stapler, and a device for attaching the buttress material to the buttress support disc. It is preferred that the buttress support disc is circular and is provided with a concentric aperture about the middle of the disc. It is further preferred that the aperture of the support disc is configured to sliding communicate with the shaft of the anvil head assembly of a circular stapler. The apparatus is assembled by threadably attaching the buttress material to the buttress support disc. It is preferable that that the middle portion of the buttress material is provided with an aperture that approximates the aperture of the support disc. If so desired, the buttress material may be provided with at least one slit extending inward from the aperture to facilitate use of the buttress material with circular staplers provided with anvil shafts having different diameters. 
         [0022]    According to yet another further embodiment of the invention, there is provided a surgical buttress assembly configured for cooperating with a surgical circular stapler. The assembly comprises a biocompatible buttress material threadably attached to a circular buttress support disc configured to slidingly communicate with the shaft of the anvil head assembly of a surgical circular stapler. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The present invention will be described in conjunction with reference to the following drawings, in which: 
           [0024]      FIG. 1  is a perspective view of an exemplary embodiment of the surgical buttress assembly present invention showing the cartridge and carrier components disengaged; 
           [0025]      FIG. 2   a  is another perspective view of the embodiment shown in  FIG. 1  showing a buttress strip interposed the cartridge and carrier components; 
           [0026]      FIG. 2   b  is a perspective view showing the buttress strip installed on the cartridge, and the loaded cartridge engaged with the carrier, and ready for loading onto the jaws of a surgical stapler; 
           [0027]      FIG. 3  is a perspective view showing a preferred orientation for installing a loaded cartridge onto the jaws of a surgical stapler; 
           [0028]      FIG. 4   a  is a perspective view of the loaded cartridge from  FIG. 3  installed onto the jaws of a surgical stapler&#39; 
           [0029]      FIG. 4   b  is a side view of the installed loaded cartridge from  FIG. 4   a;    
           [0030]      FIG. 5  is a cross-sectional end view of another exemplary embodiment of the cartridge of the present invention shown engaged with a buttress strip, and ready for loading onto a surgical stapler; 
           [0031]      FIGS. 6(   a )- 6 ( e ) are close-up cross-sectional partial end views of exemplary gripping edges and fingers of the cartridge from  FIG. 5 ; 
           [0032]      FIG. 7   a  is a side view of a prior art surgical circular stapler provided with a detachable anvil head assembly; 
           [0033]      FIG. 7   b  is a close-up view of the anvil head assembly of the surgical circular stapler shown in  FIG. 4 ; 
           [0034]      FIG. 8  is a perspective view of another exemplary embodiment of the present invention configured to cooperate with a surgical circular stapler; and 
           [0035]      FIG. 9  is a close-up exploded perspective view of a prior art anvil head assembly cooperating with the embodiment shown in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    An exemplary preferred embodiment of a surgical buttress-dispensing assembly of the present invention is shown in accompanying  FIGS. 1-4  and is generally referred to by the numeral  10 . The surgical buttress-dispensing assembly  10  comprises a cartridge  20  and a carrier  15 . The cartridge  20  is generally elongate and cylindrically shaped with an anterior end  21  and a posterior end  25 . An aperture  26  is provided approximate the posterior end  25  of the cartridge  20 . Two opposing channels bisecting the cartridge  20 , extend forward from the aperture  26  through to the anterior end  25  of the cartridge  20  thereby providing an upper half  24  separated from the lower half  28  of the cartridge  20  anterior of the aperture  26 . The upper half  24  terminates at leading edge  22  while the lower half  28  terminates at leading edge  23 . The opposing side edges of the upper and lower halves  24 ,  28  are preferably integrally provided with forward-facing tabs  27  configured to communicate with and engage the side edges of a suitable buttress strip  30 . The carrier  15  generally comprises an elongate semi-circular hollow tube provided with a backward-facing tang  16  approximate one end of the carrier  15 . As best seen in  FIGS. 2   b  and  3 , the tang  16  is configured to receive and releasingly engage therein the leading edge  22  of the upper half  24  of cartridge  20 , or alternatively, the leading edge  23  of lower half  28  of cartridge  20 . It is preferred that the cartridge  20  and carrier  15  are made of suitably thin and flexible but durable and resilient materials as exemplified by biocompatible plastics materials known to those skilled in these arts. 
         [0037]    As shown in  FIGS. 2   a  and  2   b,  the carrier  15  may be used to install and engage a buttress strip  30  onto the cartridge by folding the buttress strip  30  approximately in half and then sliding the carrier  15  into the folded buttress strip  30  so that one end of the strip  30  is within the carrier  15  while the other end of the strip  30  overlies the outer surface of the carrier  15 . The carrier  15  is then slid and manipulated over one of the halves (e.g., in  FIG. 2   a,  the upper half  24 ) of the cartridge  20  thereby engaging the side edges of the buttress strip  30  with the tabs  27  on the upper and lower halves  24 ,  28  of the cartridge  20  until the leading edge (e.g. leading edge  22  on upper half  24  per  FIG. 2   a ) engages the tang  16  of the carrier  16 . The loaded surgical buttress assembly is now ready for installation onto the articulable jaws  51 ,  53  of a surgical stapler  50 . 
         [0038]    As shown in  FIGS. 3 ,  4   a  and  4   b,  the posterior end  25  of the cartridge  20  is configured so that it may slidingly receive therein and therethrough the closed jaws  51 ,  53  of a surgical stapler  50 . By grasping and manipulating the carrier  15 , the loaded surgical buttress assembly  10  is slid onto the closed jaws  51 ,  53  to about the proximal end of the jaws  51 ,  53  after which the carrier  15  can be retracted and removed from the stapler  50 . After installation of the loaded cartridge  20 , the upper jaw  51  of the stapler  50  is interposed the upper half  24  of the cartridge  20  and the buttress strip  30 , while the lower jaw  53  is interposed the lower half  28  of the cartridge  20  and the buttress strip  30 . It is preferable to install the loaded cartridge  20  onto the stapler  50  so that the aperture  26  is approximate the proximal end of the jaws  51 ,  53 . After such installation, the upper half  24  of the cartridge communicates and cooperates with the upper jaw  51  while the lower half  28  of the cartridge  20  communicates and cooperates with the lower jaw  53 , to securely retain the buttress strip  30  in a preferred installed position during insertion of the surgical stapler  50  through a trocar (not shown) into a patient&#39;s abdominal cavity, after the jaws  51 , 53  have been opened and are manipulated within and about the abdominal cavity to a desired position, and during the staple-firing process. After staples have been fired by the surgical stapler  50 , the buttress strip  30  is separated from the cartridge  20  by severing adjacent to the inner walls of the upper and lower halves  24 ,  28  of the cartridge  20 , with blades that are integral components of the surgical stapler  50 . The cartridge  20  is retained by the stapler jaws  51 ,  53  and is removed from the patient&#39;s abdomen through the trocar with the stapler  50 . 
         [0039]      FIGS. 5 and 6  exemplify another suitable elongate cylindrical cartridge having an anterior end and a posterior end, and generally configured with an aperture approximate the posterior end from which extends forward an upper half separated from the lower half wherein the upper and lower halves are separated by a pair of opposing channels bisecting the cartridge. As exemplified by an upper half portion  60  shown in  FIG. 5 , the opposing elongate side edges  70  of the upper elongate cartridge partial wall portion  65  are formed to provide clamping means whereby a first pair of upward-facing channels  76  is formed by folding side edges  70  to extend upwards from the cartridge partial wall portion  65  and then a second pair of downward-facing channels  71  is formed by folding the upward extending side edges  70  outward and downward. As shown in  FIGS. 6(   a ) and  6 ( b ) the downward portions  71  of the opposing side edges  70  can be made to bias toward the upward extending portions of the side edges  70  thereby providing clamping means between the upward and downward portions of side edges  70 . The downward-facing channels  71  may be optionally provided with at least one pair of opposed inwardly-orientated gripping edges or fingers  72  as shown in  FIGS. 6(   c )- 6 ( e ). The lower half of the cartridge partial wall (not shown) is configured into a mirror-image of the upper half  60  shown in  FIG. 5 . As shown in  FIG. 5 , about one half of the length of a suitable buttress strip  80  is installed into the upper half of the cartridge partial wall  60  by inserting its opposing elongate side edges into the opposing downward-facing chambers  71  in between the upward-extending and downward-extending elongate side edges  70 . The other half of the buttress strip is inserted in between the corresponding downward-extending and upward-extending elongate side edges of the lower half of the cartridge partial wall. If so desired, the buttress strip  80  may be additionally secured to the cartridge after installation, with a lacing suture  81  as shown in  FIG. 5 . However, the biasing channels  71  will be sufficient to retain in position an installed buttress  80  on this exemplary cartridge during its delivery to the jaws of a surgical stapler and subsequent use. 
         [0040]    Examples of suitable buttress strips comprise biocompatible materials exemplified by synthetic base materials such as expanded polytetrafluoroethylene (ePTFE), VICRYL® (registered trade mark of Johnson and Johnson Corp., New Brunswick, N.J., USA) which is a periodontal mesh prepared from bioabsorbable copolymers derived from glycolic acid and lactic acid, DEXON® (registered trade mark of Sherwood Services AG Corp, Schaffhausen, Swizterland) which is a polyglycolic acid, and TEFLON® (registered trade mark of E.I. DuPont de Nemours and Co., Wilmington, Del., USA) which is a polytetrafluoroethylene, and collagen-absorbable hemostat, and stabilized naturally occurring materials such as a pericardium material, and other such materials. 
         [0041]    The exemplary embodiments of the surgical buttress assemblies of the present invention disclosed herein are designed to provide secure sealing of surgical staple lines produced by linear cutting types of staplers, by the precise manipulation and application of biocompatible materials within visceral host tissue for use as buttressing materials for suture lines. The system provides a “sandwich” effect by placing a reinforcing buttress layer on both sides of the stapled union of visceral tissue to visceral tissue. The reinforcement is generally carried out by placement of a buttress assembly comprising an elongate strip of biocompatible material onto the anvil and cartridge of a prior art surgical stapler device. After the biocompatible material is securely but releasingly engaged onto the jaws of the surgical stapler, the jaws are closed for insertion through a trocar into the abdominal cavity after which the jaws are opened. The user then approximates the jaws around the target sections of the tissue to be stapled and separated. The jaws are again compressed and locked into place after which, a second handle is pulled to fire the staples followed by deployment of a knife to cut the host tissue and buttress material between the staple lines. The release mechanism is then activated to release the jaws from the staple line. Jaws are withdrawn from the suture site, closed and then the stapler is removed through the trocar. 
         [0042]      FIGS. 7   a  and  7   b  exemplify a prior art surgical circular stapler  100  having a proximal end provided with a handle  110  interconnected to a detachable anvil head assembly  130  at the distal end by a moisture-proof conduit  120 . The anvil head assembly  130  comprises shaft  142  cooperating with a leading head portion  140  which facilitates insertion of the stapler  100  into a hollow organ or tissue section, and a cutting washer  146  interposed a first compression surface  144 . The distal end of the conduit  120  is enlarged to form a cylindrical cartridge  150  configured for receiving and housing surgical staples. The cylindrical cartridge  150  is fitted with a fixed-in-place second compression surface  148  opposite the first compression surface provided within the anvil head assembly  130 . The surgical staples are fired by squeezing an actuating lever  115  toward the handle  110  which results in the release of a trigger mechanism (not shown) housed within the conduit  120 . The firing force is controllable by an adjusting knob  112  located at the proximal end of the stapler  100  cooperating with the trigger mechanism. A safety catch  116  is commonly provided to ensure the staples are not accidentally fired. 
         [0043]    An exemplary embodiment of the present invention is shown in  FIGS. 5 and 6  and provides a generally circular buttress disc  160  comprising a suitable biocompatible material, examples of which include synthetic base material such as ePTFE, VICRYL®, DEXON®, TEFLON®, and collagen-absorbable hemostat. Alternatively, stabilized naturally occurring materials such as a pericardium material, and other such materials may be used. The buttress disc  160  is provided with an aperture  162  positioned about the centre of the disc  160 , said aperture  162  configured for slidingly cooperating with the shaft  142  of the anvil head assembly  130  of the stapler  100 . The buttress disc  160  may optionally be provided with at least one, and preferably a plurality of slits  164  extending inward from aperture  162  to enable sliding cooperation of the buttress disc  160  with shafts having different diameters. The buttress disc  160  is attached to an orientating disc  155  provided with a plurality of bores  157  therethrough, by suturing the disc  160  to the bores  157  with a suitable running suture material  165 . The orientating disc  155  is configured to position and maintain the buttress disc  160  in a coplanar orientation relative to the cartridge  150  and anvil head assembly  130 . It is preferable that the outer diameter of the buttress disc  160  is slightly larger than the outer diameters of the first and second compression surfaces  144  and  148 . 
         [0044]    The orientating disc  155  to which a buttress disc  160  is sutured, is slid over the shaft  142  of the anvil head assembly  130  until the orientating disc is adjacent the first compression surface  144 , after which the cutting washer  142  is slid over the shaft  142  until the cutting washer  142  is adjacent the orientating disc  155 , thereby producing a loaded anvil head assembly  130 . The loaded anvil head assembly  130  is then inserted head portion  140  first into the distal portion of a severed tubular tissue until a sufficient length of the severed tubular tissue extends beyond the shaft  142  to enable securing of the end of the tissue to the shaft  142  with a suture material. The severed end of the tubular tissue opposite the distal end is tied-off with a suture material after which, the distal end of the shaft  120  of the surgical stapler  100  is inserted into the proximal end of the severed tubular tissue until the second compression surface  148  fixed to the cylindrical cartridge  150  abuts the tied-off end of the tissue section. The shaft  142  of the anvil head assembly  130  is then maneuvered against the end of the cylindrical cartridge  150  thereby contacting the opposing tied-off ends of the severed tissues to be rejoined. The actuating lever  115  is then compressed against the handle  110  resulting in the firing of staples in a circular pattern after which they are compressed between the first and second compression surfaces  144  and  148  thereby conjoining the two severed tubular tissue sections. The cutting washer  146  is then activated to severe the opposing tied ends from the conjoined tissues thereby cutting out the centre of the conjoined tissue sections and a center portion of the buttress disc  160 , thereby providing a conjoined continuous tubular tissue with the buttress material reinforcing the staple line against the inner surface of the conjoined tubular tissue. Those skilled in these arts will understand that it is optional, if so desired, to reinforce the staple line against the outer surface of the conjoined tissue by providing a second orientating disc  155  to which a buttress disc  160  is sutured, adjacent the second compression surface  148  (not illustrated) prior to inserting the distal end of the shaft  120  of the surgical stapler  100  into the proximal end of the severed tubular tissue against the tied-off end of the tissue section. 
         [0045]    In view of numerous changes and variations that will be apparent to persons skilled in the art, the scope of the present invention is to be considered limited solely by the appended claims.