Abstract:
The present invention relates to surgical instruments and methods for enhancing properties of tissue repaired or joined by surgical staples and, more particularly to surgical instruments and methods designed to enhance the properties of repaired or adjoined tissue at a target surgical site, especially when sealing an anastomosis between adjacent intestinal sections so as to improve tissue viability, prevent tissue infection, and to prevent leakage.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to surgical instruments and methods for enhancing properties of tissue repaired or joined by surgical staples and, more particularly to surgical instruments and methods designed to reinforce the repaired or adjoined tissue at a target surgical site. 
       BACKGROUND OF THE INVENTION 
       [0002]    Throughout the years the medical field has utilized various techniques in an effort to join or bond body tissue together. Historically, suturing was the accepted technique for rejoining severed tissues and closing wounds. Suturing is achieved with a surgical needle and a suturing thread, with the intended function of sutures to hold the edges of a wound or tissue against one another during the healing process. Staples are used to replace suturing when joining or anastomosing various body structures, such as, for example, the bowel. The surgical stapling devices employed to apply staples are generally designed to simultaneously cut and seal an extended segment of tissue in a patient. 
         [0003]    Linear or annular/circular surgical stapling devices are employed by surgeons to sequentially or simultaneously apply one or more rows of surgical fasteners, e.g., staples, to body tissue for the purpose of joining segments of body tissue together and/or for the creation of an anastomosis. Linear surgical stapling devices generally include a pair of jaws or finger-like structures between which body tissue to be joined is placed. When the surgical stapling device is actuated, firing bars move longitudinally and contact staple drive members in one of the jaws, and surgical staples are pushed through the body tissue and into and against an anvil in the opposite jaw thereby crimping the staples closed. A knife blade may be provided to cut between the rows/lines of staples. 
         [0004]    Annular or circular surgical stapling devices generally include an annular staple cartridge assembly including a plurality of annular rows of staples (typically two or three), an anvil assembly operatively associated with the annular cartridge assembly, and an annular blade disposed internal of the rows of staples. In general, an end-to-end anastomosis stapler typically places an array or group of staples into the approximated sections of a patient&#39;s bowels or other tubular organs. The resulting anastomosis contains an inverted section of bowel which contains numerous “B” shaped staples to maintain a secure connection between the approximated sections of bowel. 
         [0005]    Anastomotic leaks may result in significant morbidity and frequently death. In addition to the use of surgical staples, sealants, e.g., synthetic or biological sealants, can be applied to the surgical site to guard against leakage. The biological sealants are typically applied to the outer surface of the anastomosis in a separate step. 
         [0006]    U.S. Pat. No. 7,547,312 which is directed to circular stapler buttress discloses an implantable medical device adapted to reinforce a surgical opening formed in a patient with a circular stapler having a cutting blade, said device comprising: a buttress material adapted for mounting on said circular stapler, said stapler having an anvil that is larger in diameter than said surgical opening that is created by said cutting blade, wherein following stapling with said stapler and cutting with said cutting blade, said buttress material is adapted to reinforce stapled tissue surrounding said surgical opening created by said cutting blade in said patient and has an adaptive opening formed therein; wherein the buttress material comprises a bioabsorbable web material substantially in the form of a circle, said circular web material having an outer edge and a centrally located opening delimiting an inner edge; at least two disruptable areas positioned along said outer edge of said circular web material and at least two protrusions of web material each extending beyond each of said at least two disruptable areas, wherein said protrusions are adapted to attach said buttress material to said circular stapler; a series of slits in said bioabsorbable web material positioned between said outer edge and said inner edge of said circular web material; wherein said series of slits serve to create said adaptive opening in said buttress material; wherein said adaptive opening corresponds to said surgical opening in said patient and has a diameter smaller than said diameter of said anvil; and wherein said adaptive opening allows said anvil to be removed therethrough without causing permanent alteration to said buttress material. 
         [0007]    U.S. Pat. No. 8,123,767 which is directed to a circular stapler buttress discloses an implantable medical device for use with a circular stapler adapted to create a substantially circular hole in a patient, said circular stapler having a stapler anvil portion with a first compression surface and a stapler body portion with a second compression surface, said implantable medical device comprising: a first buttress made of a bioabsorbable web material having a first contact surface adapted to attach to said stapler anvil without use of an adhesive on said first compression surface and said first contact surface; a second buttress made of a bioabsorbable web material having a second contact surface adapted to attach to said stapler body without use of an adhesive on said second compression surface and said second contact surface; at least one protrusion disruptably connected to said second buttress, said protrusion having an adhesive on at least a portion thereof to attach said second buttress to said stapler body portion; and wherein the first and second buttresses reinforce said hole created by said stapler in said patient when staples are applied and both have an adaptive opening therethrough formed from a series of slits positioned between inner and outer edges of the first and second buttresses. 
         [0008]    U.S. Pat. No. 8,123,766 which is directed to a circular stapler buttress discloses an implantable medical device adapted to reinforce tissue stapled together with a circular stapler having a generally circular cutting blade, the device comprising: a buttress material adapted for mounting on the circular stapler; and a plurality of slits in the buttress material, the slits generally extending in an approximately radial direction, wherein, a reinforcing portion of the buttress material is configured to remain stapled to tissue in a patient and an inner portion of the buttress material is configured to be cut away from the reinforcing portion by the cutting blade upon actuation of the circular stapler and cutting blade, resulting in a severed inner edge of the reinforcing portion and a severed outer edge of the inner portion, and wherein the slits extend through the severed inner edge of the reinforcing portion. 
         [0009]    U.S. Pat. No. 8,679,137 which is directed to a circular stapler buttress discloses a medical device adapted to reinforce tissue stapled together with a circular surgical stapler having an anvil and a generally circular cutting blade, the medical device comprising: an implantable buttress material adapted for mounting on said circular stapler; and at least one adaptive opening in the buttress material wherein a reinforcing portion of the buttress material is configured to remain stapled to tissue in a patient and an inner portion of the buttress material is configured to be cut away from the reinforcing portion by the cutting blade upon actuation of the circular stapler and cutting blade, resulting in a severed inner edge of the reinforcing portion and a severed outer edge of the inner portion, and wherein the at least one adaptive opening is adapted to extend to a central opening in said buttress material created by cutting of said inner portion away from said reinforcing portion with said generally circular cutting blade. 
         [0010]    U.S. Pat. No. 7,776,060 which is directed to a circular stapler buttress combination discloses a combination medical device comprising: a) a circular stapler instrument, comprising a staple cartridge component and corresponding anvil component, and b) a buttress adapted to be a) stably positioned upon the staple cartridge and/or anvil components of the stapler prior to, or at the time of, use, b) while in position upon the stapler component(s), to then be delivered to a tissue site in combination with the stapler components, c) upon delivery of the components and positioned buttress to the tissue site, to provide a first region of buttress material to buttress a seam between tissue sections upon activation of the stapler instrument, and d) to permit the removal of one or more portions of a second region upon activation of a stapler instrument knife provided by the stapler, the second region being generally concentric to the first region and wherein the first region and the second region are formed of dissimilar materials. 
         [0011]    U.S. Pat. No. 8,529,819 which is directed to wound closure material discloses a method comprising: obtaining a polymeric material selected from the group consisting of glycolic acid, lactic acid, glycolide, lactide, dioxanone, trimethylene carbonate, caprolactone, and combinations thereof; forming the polymeric material into an article that does not possess orientation in a single direction by subjecting the polymeric material to a temperature of from about 95 C to about 230 C and a pressure of from about 1 psi to about 2500 psi, for a period of time from about 5 seconds to about 10 minutes; and recovering the article. 
         [0012]    U.S. Pat. No. 9,161,753 which is directed to buttress fixation for a circular stapler discloses a circular stapling apparatus, comprising: an anvil assembly including an anvil member and a shaft; a tubular body portion having a staple cartridge including a plurality of staple receiving slots defined in a tissue contacting surface of the staple cartridge, each of the plurality of staple receiving slots including a staple disposed therein, and at least one of the plurality of staple receiving slots includes a notch, the shaft of the anvil assembly being connectable to the tubular body portion so that the anvil assembly is movable toward and away from the tubular body portion, the staple cartridge including a staple pusher disposed therein, the staple pusher having a plurality of fingers for driving the staples out of the plurality of staple receiving slots, at least one of the fingers including a protrusion; and a buttress material removably attached to the staple cartridge by at least one anchor releasably retained within the notch, the staple pusher being movable to move the protrusion into engagement with the anchor retained within the notch to push the anchor out from the notch. 
         [0013]    U.S. Pat. No. 9,113,885 which is directed to buttress assembly for use with surgical stapling device discloses an apparatus for joining two hollow organ sections, the apparatus comprising: a staple cartridge component including a plurality of surgical staples in an annular array; an anvil component defining a plurality of staple pockets for deforming the plurality of surgical staples, the anvil component movable relative to the staple cartridge component between spaced apart and approximated positions to adjustably clamp tissue between the staple cartridge and anvil components; a knife member concentrically arranged with the plurality of surgical staples in the staple cartridge component, the knife member defining a lumen therethrough, the knife member movable relative to the staple cartridge component; and a buttress member including a pair of anchor portions securely engaging an inner wall of the staple cartridge component, the inner wall defining a passage dimensioned to receive the knife member therein, wherein each anchor portion of the pair of anchor portions is disposed radially inward of the inner wall of the staple cartridge component. 
         [0014]    U.S. Pat. No. 9,186,144 which is directed to buttress support design for an anvil discloses an apparatus for joining two hollow organ sections with an annular array of surgical staples, the apparatus comprising: a staple cartridge component including a plurality of surgical staples in an annular array; an anvil component including an anvil member and a shaft extending therefrom, the anvil member defining a plurality of staple pockets for deforming the plurality of surgical staples, the anvil component movable relative to the staple cartridge component between spaced apart and approximated positions to adjustably clamp tissue between the staple cartridge and anvil component; a buttress member in registration with at least a portion of the plurality of staple pockets defined in the anvil member; and a buttress mount secured to the shaft of the anvil component, the buttress mount configured to be received in a recess defined in the anvil member, the buttress mount including at least one support member configured to engage a peripheral edge of the recess of the anvil member to secure the buttress mount within the recess, wherein the buttress mount is attached to a distal surface of the buttress member. 
         [0015]    U.S. Pat. No. 9,010,612 which is directed to buttress support design for an anvil discloses an apparatus for joining two hollow organ sections with an annular array of surgical staples, the apparatus comprising: a staple cartridge component including a plurality of surgical staples in the annular array; an anvil component including an anvil member and a shaft extending therefrom, the anvil member defining a plurality of staple pockets for deforming the plurality of surgical staples, the anvil component movable relative to the staple cartridge component between spaced apart and approximated positions to adjustably clamp tissue between the staple cartridge and anvil components; a buttress member concentrically aligned with the plurality of staple pockets defined in the anvil member; and a buttress mount detachably secured with the shaft of the anvil component, the buttress mount including an annular ring member and at least one support member radially extending outward from the annular ring member to secure the buttress member to the anvil member, the at least one support member at least partially underlying the buttress member to provide support thereto, wherein the buttress mount is separate from the buttress member, and the annular ring member of the buttress mount is secured to the shaft of the anvil component. 
         [0016]    U.S. Pat. No. 9,010,609 which is directed to a circular stapler including buttress discloses a surgical stapling device for joining tissue portions, comprising: a handle assembly; a tubular body portion supported on a distal end of the handle assembly, the tubular body portion having a staple cartridge assembly containing a plurality of surgical staples in an annular array, the tubular body portion including an inner surface and an outer surface, a distal portion of the tubular body portion including at least one attachment portion defining a first cleat; an anvil assembly at a distal end of the surgical stapling device, the anvil assembly having a shaft for removably connecting the anvil assembly to the tubular body portion, the anvil assembly and tubular body portion being juxtaposed with respect to one another along the shaft and arranged so as to be approximated with respect to one another; a buttress material supported by the tubular body portion, the buttress material being disposed between the anvil assembly and the staple cartridge assembly; and an attachment member adapted for engagement with the tubular body portion and the buttress material to secure the buttress material to the tubular body portion, the attachment member defining a first end and a second end, the attachment member being adapted to engage the tubular body portion by insertion of at least one of the first and second ends thereof into the first cleat of the at least one attachment portion. 
         [0017]    U.S. Pat. No. 9,005,243 which is directed to a buttress and surgical stapling apparatus discloses a surgical stapling apparatus comprising: a staple cartridge containing at least one staple; an anvil having a staple forming surface; and a buttress positioned adjacent the anvil or the cartridge, the buttress comprising a non-porous layer disposed between first and second porous layers and a reinforcement member positioned within the non-porous layer, wherein pores of the porous layers do not span across the entire thickness of the porous layers. 
         [0018]    U.S. Pat. No. 8,167,895 which is directed to an anastomosis composite gasket discloses a method of forming an anastomosis between intestinal tissue sections, comprising the steps of: providing a circular surgical anastomosis device, the circular surgical anastomosis device including: an anvil assembly having an anvil member; and a tubular body portion having an annular knife operatively disposed therein and a shaft disposed radially inward of the annular knife, the anvil assembly being attached to the shaft of the tubular body; inserting the anvil assembly into a first intestinal section; inserting the tubular body portion into a second intestinal section; disposing a structure, including at least a first ring of a first material, a second ring of a second material, and a third ring between the first intestinal section and the second intestinal section, the first ring comprising a disk having an aperture and the second ring comprising a disk having an aperture, the second ring having an outer perimeter, wherein the outer perimeter of the second ring is directly attached to the first ring and disposed within the aperture of the first ring, and the third ring radially extending outward from the first ring and beyond staple retaining slots of the tubular body portion, the structure possessing a wound treatment material consisting of at least one of an adhesive and a sealant; and firing staples through the intestinal tissue sections and through the structure. 
         [0019]    U.S. Pat. No. 7,938,307 which is directed to support structures and methods of using the same discloses an apparatus for forming an anastomosis between adjacent intestinal sections of tissue, comprising: a) an anastomosis device having an anvil and a tubular body portion, the anvil being selectively attachable to the tubular body portion by a shaft; and b) a support structure for deposition between the intestinal sections of tissue, the support structure including a body defining an aperture therein for receiving the shaft, the body having an outer terminal edge, wherein the body is compressible so that the outer terminal edge of the body extends beyond the outer radial surface of the anvil and the tubular body portion, the support structure including at least one layer of expandable material disposed at the outer terminal edge of the body, wherein the support structure has an unhydrated condition wherein the body has a first diameter and a first thickness, and a hydrated condition wherein the body has a second diameter greater than the first diameter and a second thickness greater than the first thickness, and wherein the body expands from the first diameter and the first thickness to a second diameter and a second thickness upon application of a fluid thereto, the body being constructed from a first part of a two-part wound treatment material, and the fluid applied thereto is a second part of the two-part wound treatment material. 
         [0020]    U.S. Patent Publication No. 2013/0123816 which is directed to hydrophilic medical devices discloses a method of making an absorbent surgical buttress, comprising: generating a plurality of fibers; collecting the plurality of fibers so that they adhere to one another and form a non-woven material; plasma treating at least a portion of a surface of the non-woven material with an ionizable gas species or combination of ionizable gas species configured to chemically modify or functionalize the surface of the non-woven material; and cutting the non-woven material into a desired shape for a surgical buttress. 
         [0021]    U.S. Patent Publication No. 2005/0059997 which is directed to a circular stapler buttress discloses a reinforcement device for use with a circular stapler that is adapted to create and seal a surgical opening in a patient comprising: a buttress adapted for mounting on the circular stapler, the stapler having an anvil that is larger in diameter than the surgical opening that is created by the stapler, wherein following stapling with the stapler, the buttress reinforces the surgical opening created by the stapler in the patient; wherein the buttress includes at least one adaptive opening created by the circular stapler which corresponds to the surgical opening in the patient, said adaptive opening when circular having a diameter smaller than the diameter of the anvil, and wherein the adaptive opening in the buttress allows the anvil to be removed therethrough without causing permanent alteration to the buttress. 
         [0022]    U.S. Patent Publication No. 2014/0217148 which is directed to a buttress attachment for circular stapling device discloses a circular stapling device, comprising: a handle assembly; an elongate body that extends from the handle assembly; a cartridge assembly mounted on a distal end portion of the elongate body, the cartridge assembly including: a housing; a pusher member supported within the housing and being movable between a first position and a second position; a retaining ring member supported on the housing and being configured and arranged to move between a radially constricted condition and a radially expanded condition in response to movement of the pusher member; and a fastener cartridge body supported on the housing and having a tissue engaging surface that extends to an annular edge; and a circular cartridge buttress member having a body portion and an extension portion, the body portion being supported on the tissue engaging surface of the fastener cartridge body, the extension portion extending from the body portion and over the annular edge of the tissue engaging surface, the retaining ring member securing the extension portion against at least one of the fastener cartridge body and the housing when in the radially constricted condition, the retaining ring member releasing the radially extension portion when the retaining ring member moves to the expanded condition in response to a movement of the pusher member from the first position to the second position so that the body portion of the cartridge buttress separates from the tissue engaging surface of the fastener cartridge body. 
         [0023]    U.S. Patent Publication No. 2014/0197224 which is directed to a buttress retainer for an anvil discloses an apparatus for joining two hollow organ sections with an annular array of surgical staples, the apparatus comprising: a staple cartridge assembly including a plurality of surgical staples in an annular array; an anvil assembly including an anvil member and a shaft extending therefrom, the anvil member including a proximal surface defining a plurality of staple pockets for deforming the surgical staples, the anvil assembly movable relative to the staple cartridge assembly between spaced apart and approximated positions to adjustably clamp tissue between the staple cartridge and anvil assemblies; and a buttress assembly including: a ring member configured to engage a knife member, the ring member secured with the anvil member; a buttress member disposed in a superposed relation with the plurality of staple pockets defined in the anvil member; and a retaining member having an attaching member configured to be secured with the ring member to secure the buttress member between the cut ring and the retaining member, and to position the buttress member relative to the anvil assembly. 
         [0024]    Post-operative leakage of the stapled tissue seals, including anastomotic seals has been shown to lead to morbidity and mortality. A number of technologies are related to direct application of material to the serosal layer after stapling by either dripping or spraying. The problems associated with these techniques are that access is very difficult and visual assessment as to whether or not the material was applied to the right spot and completely around the anastomosis. The material is also applied on top of the serosal layer when the target site is actually subserosal along the staple line. Applying a therapeutic agent to the serosal layer of the colon requires the material to migrate through the serosa and to the staple region, then provide a biological affect, and overcome the problems associated with a leak formation, all within 24-48 hours, and assuming the material was applied to the correct spot intraoperatively. One of the most challenging steps in the application of a topical adjunctive therapy to a colorectal anastomosis is to provide the material to the site because of the extreme limitation in access to the site. Some colorectal anastomoses are performed relatively “low” in a patient (i.e. lower anterior resection) and the actual staple line is deep within the pelvic canal, which makes a topical application of material around the circumference very difficult. 
         [0025]    The known compression anastomotic rings lack the reliability of stapled anastomosis. The staple based anastomotic joining is a widely accepted practice but there is a need in improving the technology to prevent post-operative leakage of the stapled tissue seals to improve the viability of the tissue joined by staples. There is a need in an improved supporting buttress which is easy to deploy on/from existing anastomotic staplers. 
       SUMMARY OF THE INVENTION 
       [0026]    The present invention relates to surgical instruments and methods for enhancing properties of tissue repaired or joined by surgical staples and, more particularly to surgical instruments and methods designed to enhance the properties of repaired or adjoined tissue at a target surgical site, especially when sealing an anastomosis between adjacent intestinal sections so as to improve tissue viability, prevent tissue infection, and to prevent leakage. 
         [0027]    The present invention, in one aspect, relates to a circular surgical stapler for anastomotic joining of tissue having a stapling head connected to an opposing anvil, with stapling head containing a plurality of deployable staples in concentric arrays. The present invention, in one embodiment, relates to a circular stapling assembly for anastomotically joining tubular tissue sections comprising: a circular anvil; a circular staple head assembly having a centrally located passage and a knife located in the passage; a moveable shaft connecting the anvil and staple head; an elongated shaft extending from the staple head assembly and gripping means; and at least one reinforcing buttress comprising a substantially flat disk of a flexible, bioabsorbable material having a centrally located aperture and a plurality of radiating slits directed from said centrally located aperture towards a periphery of said disk that forms a plurality of leaflets, said slits terminating in end apertures at a distance from said periphery. 
         [0028]    The present invention, in another embodiment, relates to a circular anastomosis stapler kit comprising: a reinforcing buttress material comprising a substantially flat disk of a flexible, bioabsorbable material having a centrally located aperture and a plurality of radiating slits directed from said centrally located aperture towards a periphery of said disk that forms a plurality of leaflets, said slits terminating in end apertures at a distance from said periphery; an anastomotic stapler comprising a stapling head and an anvil moveable longitudinally relative to the stapling head and mounted on an axially extending moveable shaft, with the stapling head containing a plurality of deployable staples, a deployment tool comprising a hollow cylindrical body with a slidable plunger partially disposed in said body; a cylindrical radially expandable spring sized to fit within said hollow cylindrical body and within a knife cavity of said stapling head. 
         [0029]    The present invention, in yet another embodiment, relates to a method of establishing an anastomotic joint between tubular tissue lumens with the anastomotic stapler kit comprising the steps of: axially positioning the spring in a compressed state inside the hollow cylindrical body; axially positioning the buttress between the spring inside the hollow cylindrical body and the stapling head; optionally inserting the hollow cylindrical body into a knife cavity of the stapling head thus bending the leaflets of the buttress into the knife cavity; moving the spring using the slidable plunger from the hollow cylindrical body into a knife cavity of the stapling head thus bending the leaflets of the buttress into the knife cavity; allowing the spring to radially expand in the knife cavity thus immobilizing the leaflets inside the knife cavity with said spring; removing the hollow cylindrical body; positioning the stapling head inside a first tubular tissue and positioning the anvil inside a second tubular tissue; connecting the anvil to the stapling head via the shaft; approximating the anvil and the stapling head and compressing said first and second tubular tissues and said buttress between the stapling head and the anvil; firing the anastomotic stapler and establishing the anastomotic joint between said first and second tubular tissues; severing the leaflets from the buttress. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0030]      FIG. 1  shows a perspective view of a circular surgical stapling instrument. 
           [0031]      FIGS. 2A and 2B  show schematic top views of the reinforcing buttress. 
           [0032]      FIGS. 3A and 3B  show schematic perspective views of the buttress deployment tool. 
           [0033]      FIGS. 4A and 4B  show a schematic perspective view and schematic top view of the spring. 
           [0034]      FIGS. 5A, 5B, 5C and 5D  show schematic views of various embodiments of the spring. 
           [0035]      FIGS. 6A, 6B and 6C  show schematic cross-sectional side views of the initial position in the use of deployment tool to deploy buttress onto stapling head. 
           [0036]      FIGS. 7A, 7B, 7C and 7D  show schematic cross-sectional side views of the process of deploying buttress using the deployment tool onto stapling head. 
           [0037]      FIG. 8  shows a schematic cross-sectional side view of buttress mounted onto stapling head. 
           [0038]      FIG. 9  shows a schematic cross-sectional partial side view of a portion of circular stapler performing anastomotic joining of tubular tissues. 
           [0039]      FIG. 10  shows a schematic cross-sectional partial side view of a portion of circular stapler performing anastomotic joining of tubular tissues. 
           [0040]      FIG. 11  shows a schematic cross-sectional side view of an anastomotic joint. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0041]    Surgery often involves joining of two or more layers of tissue together with optional simultaneous sectioning of a portion of the tissue along the staple line. For example, colorectal surgery in many cases involves the resection of a segment of the colon and rectum. Following a colorectal resection, the colon and rectum are drawn together with a circular stapler and an end-to-end anastomosis is performed. Post-op leakage of the anastomosis has been shown to lead to morbidity and mortality. 
         [0042]    Typical surgical stapling instruments have a staple-containing component and an opposing anvil component, between which at least two tissue layers to be joined are compressed prior to delivery of staples from the staple-containing component, whereby staples are piercing both tissue layers and are bent, deformed, or closed against the opposing anvil component. 
         [0043]    Referring now to  FIG. 1 , a generic surgical anastomosis stapling instrument or stapling device for performing a circular anastomosis stapling operation is shown, with the figure taken from the U.S. Pat. No. 5,271,544 “Surgical anastomosis stapling instrument”, assigned to Ethicon, Inc., Somerville, N.J., and incorporated herein by reference in its entirety for all purposes. Various modifications and iterations of the shown stapling device are known in the art, having similar features. The circular anastomosis surgical stapling instrument  500  includes a distal stapling head assembly  600  connected by a longitudinally curved support shaft assembly  700  to a proximal actuator handle assembly  800 . The stapling instrument includes an anvil assembly or anvil  1000  which is slidable longitudinally relative to the stapling head assembly  600  and mounted on an axially extending moveable shaft  1040 . An optional rotatable adjusting knob  820  is provided at the proximal end of the actuator handle assembly  800  for adjusting the spacing between the stapling head assembly  600  and the anvil assembly  1000 . An optional movable indicator  840  is visible through an optional window  850  on top of the handle assembly  800  to indicate the staple height selected by rotation of the adjusting knob  820 . The indicator  840  is movable indicating that the anvil gap is within a desired operating range of the stapling instrument  500 . The position of the indicator  840  also indicates whether the selected staple height is large or small. 
         [0044]    A staple actuating lever  860  is pivotally mounted on the actuator handle assembly  800  for driving the surgical staples from the stapling head assembly  600  when the anvil assembly  1000  is closed to provide the desired staple height. A pivotal latching member  880  is mounted on the handle assembly  800  for locking the staple actuating lever  860  against movement to preclude actuation of the stapling head assembly  600  when the anvil gap is outside of a predetermined range. The stapling head assembly  600  includes a tubular casing  610  as well as a hollow tubular connector  640  at the proximal end of the casing  610  which receives the distal end of the support shaft  700 . A ferrule or sleeve  720  overlaps the joint between the tubular connector  640  and the distal end of the support shaft  700 . The proximal end of the support shaft  700  is received by a tubular extension  740  at the distal end of the actuator handle assembly  800 . A ferrule or sleeve  760  overlaps the joint between the proximal end of the support shaft  700  and the distal end of the tubular extension  740 . The movable indicator  840  is visible through a window  850  on top of the handle assembly  800  to indicate the staple height selected by rotation of the adjusting knob  820 . 
         [0045]    Other versions and modifications of the circular surgical stapler are known to a skilled artisan. There are typically at least two and frequently more concentric stapling lines or concentric circular rows of staples-containing slots surrounding shaft  1040 , with staples in each row typically staggered or offset relative to the staples in the adjacent row, to improve the sealing and prevent leakage along the stapling line. 
         [0046]    Clinical evidence shows the formation of a full wall intestinal defect at or near the anastomotic site may occur as soon as 1-2 days post-op, with typical time period when the clinical symptoms of leaks occur being from 1 to 5 days post-op. See, for example, K. Jönsson, H. Jiborn, B. Zederfeldt, “Breaking strength of small intestinal anastomoses”, The American Journal of Surgery, v. 145, pp. 800-803, 1983; Y.-H. Ho, M. A. T. Ashour, “Techniques for colorectal anastomosis”, World Journal of Gastroenterology, 16(13), pp. 1610-1621, 2010. 
         [0047]    According to the present invention, there is provided a reinforcing buttress and devices and methods to deploy such reinforcing buttress, with the reinforcing buttress attached by the staples from a circular anastomotic stapler during establishment of the anastomotic joint connecting two parts of a tissue lumen. 
         [0048]    Referring now to  FIG. 2A , a schematic top view of one embodiment of a reinforcing buttress  10  of the present invention is shown. Buttress  10  comprises a substantially flat disk, having a round centrally located aperture  20  and a plurality of radial slits  30  which start from an edge of aperture  20  and extend radially towards a peripheral edge of buttress  10  but not reaching external circumference  35  of buttress  10 . Radial slits  30  terminate at a distance D from external circumference  35 . Distance D corresponds to area being stapled by the anastomotic stapler and is at least equivalent to the width of staple lines (not shown). Distance D further corresponds distance between stapling head outside circumference and circular knife. Radial slits  30  form triangularly shaped leaflets or segments or flaps  32  which are used for attaching buttress  10  to stapler head  600  and anvil  1000 . Triangular flaps  32  can be bent out of plane of buttress  10  by exerting force on triangular flaps  32 . Radial slits  30  terminate in stress relieving end apertures  40  which prevent cracking of buttress  10  material when triangular flaps  32  are bent out of plane of buttress  10 . Radial slits  30  can be preferably evenly spaced apart. 
         [0049]    Referring to now  FIG. 2B , severing of central portion of buttress  10 , i.e. of leaflets  32  by the circular knife can be made at the end of radial slits  30  or at the stress relieving end apertures  40 , as schematically shown by dashed line L 1 . Alternatively, severing of central portion of buttress  10 , i.e. of leaflets  32  by the circular knife can be made between the end of radial slits  30  or between the stress relieving end apertures  40  and external circumference  35  of buttress  10 , but proximal to the end of radial slits  30  or stress relieving end apertures  40 , as schematically shown by dotted line L 2 . 
         [0050]    Referring now to  FIGS. 3A and 3B , a schematic perspective view of a buttress deployment tool  100  is shown, with  FIG. 3A  showing tool  100  comprising a hollow cylindrical body  110  which has an axial cylindrical opening  115  surrounded by a wall  120 . Plunger  135  is partially disposed in cylindrical opening  115 , with plunger  135  comprising, as also shown in  FIG. 3B , stem  135  on distal end of which is positioned a piston  137 . On proximal end of stem  135  is positioned handle  136 . Piston  137  is positioned close to distal end  111  of deployment tool  100  and is sized to be slidably moveable within cylindrical body  110  when actuated by handle  136 . 
         [0051]    Referring now to  FIG. 4A , a schematic perspective view of a spring  200  shown, with spring  200  comprising a spiral spring formed as a generally cylindrical spiral of height  220  made of a flat metallic or polymeric strip or foil  210  resulting in radially expandable resilient spiral of tightly wound into a cylinder.  FIG. 4B  shows schematic top view of spring  200  having external diameter  230  and internal diameter  235 . Spring  200  can comprise from less than 2 full circles or turns of foil as shown in  FIG. 4A , to slightly over 2 full circles, as shown in  FIG. 4B , to 3-10 full circles. 
         [0052]    Referring now to  FIGS. 5A-5D , schematic views of various embodiments of spring  200  are shown.  FIG. 5A  shows spring  200  as described above.  FIG. 5B  shows a spring  200   b  comprising a cylindrical body  240  with a plurality of memory-shape radially expanding arms  245 .  FIG. 5C  shows a spring  200   c  comprising a round support ring  250  with a plurality of memory-shape radially expanding arms  255 .  FIG. 5D  show a side view of a spring  200   d  comprising a cylindrical body  260  with a plurality of memory-shape radially expanding flaps  265 . All preferred embodiments of spring  200  provide a hollow, generally cylindrical structure which can be compressed radially and then expand radially when compression is removed. 
         [0053]    Referring now to  FIG. 6A , a schematic cross-sectional side view illustrates the use of deployment tool  100  to deploy buttress  10  onto stapling head  600 . Deployment tool  100  is shown axially aligned and abutting stapling head  600 , with buttress  10  positioned between and compressed by distal end  111  of deployment tool  100  and stapling head  600 . Wall  120  of cylindrical body  110  is shown aligned with stapling head  600 , with spring  200  positioned in the compressed state within cylindrical body  110  at distal end  111  of deployment tool  100 . Stapling head is shown having circular knife  620  deployed within knife cavity  630 . Deployment mechanisms for knife  630  and staple are not shown for simplification. 
         [0054]    Referring now to  FIG. 6B , piston  137  has an optional cavity  139  so as to more easily to accommodate shaft  1040  when shaft  1040  is in extended position i.e. protruding above stapling head  600  as shown in  FIG. 6B . Referring now to  FIG. 6C , a schematic cross-sectional side view illustrates an embodiment of deployment tool  100  and its use of to deploy buttress  10  onto stapling head  600 . Deployment tool  100  is shown axially aligned and abutting stapling head  600 , with buttress  10  positioned between and compressed by distal end  111  of deployment tool  100  and stapling head  600 . Wall  120  of cylindrical body  110  is aligned with stapling head  600 , with spring  200  positioned in the compressed state within cylindrical body  110  at distal end  111  of deployment tool  100 . Stapling head  600  has a circular knife  620  deployed within knife cavity  630 . Piston  137  having an optional cavity  139  so as to more easily to accommodate shaft  1040  when shaft  1040  is in extended position. 
         [0055]    In the embodiment shown in  FIG. 6C , the outside diameter of cylindrical body  110  is selected so that cylindrical body  110  can fit within knife cavity  630 . This is different from the embodiments of  FIGS. 6A, 6B , where outside diameter of cylindrical body  110  matches the outside diameter of stapling head  600 . For deployment of buttress  10  onto stapling head and securement of buttress  10  with spring  200 , pushing on handle  136  in the direction of arrow  138  moves stem  135  and piston  137  towards distal end  111 . 
         [0056]    As shown in  FIGS. 7A and 7B , corresponding to embodiments of  FIGS. 6A and 6B , and as a result of pushing handle  136  in the direction of arrow  138 , which moves stem  135  and piston  137  towards distal end  111 , spring  200  is moved into knife cavity  630 , bending flaps  32  into knife cavity  630 . Spring  200  expands radially and presses flaps  32  against knife  620  within knife cavity  630 . Thus spring  200  immobilizes buttress  10  on stapling head  600  by pressing flaps  32  and holding flaps  32  against circular knife  620 . 
         [0057]    Referring now to  FIGS. 7C and 7D , corresponding to embodiment of  FIG. 6C , cylindrical body  110  is pushed into knife cavity  630 , bending flaps  32  into knife cavity  630 , resulting in schematic cross-sectional view of  FIG. 7C . In the embodiments shown in  FIGS. 7C and 7D , outside diameter of cylindrical body  110  is selected so that cylindrical body  110  can fit within knife cavity  630 . This is different from embodiments of  FIGS. 7A, 7B , where outside diameter of cylindrical body  110  is close to or matches the outside diameter of stapling head  600 . 
         [0058]    Pushing on handle  136  in the direction of arrow  138  and moving stem  135  and piston  137  towards distal end  111 , spring  200  is then moved into knife cavity  630 , while simultaneously withdrawing cylindrical body  110  from knife cavity  630 , resulting in schematic cross-sectional view of  FIG. 7D . Spring  200  expands radially and presses flaps  32  against knife  620  within knife cavity  630 . Thus spring  200  immobilizes buttress  10  on stapling head  600  by pressing flaps  32  and holding flaps  32  against circular knife  620 . 
         [0059]    After immobilizing buttress  10  on stapling head  600  via spring  200  as described above, and referring to  FIG. 8 , showing a schematic cross-sectional side view, deployment tool  100  is removed, leaving stapling head  600  supported on shaft assembly  700  with moveable shaft  1040  visible in knife cavity  630 . Buttress  10  is disposed on stapling head  600 , with a portion of buttress  10  from external circumference  35  to approximately termination of radial slits  30 , i.e. a portion corresponding to approximately distance D from external circumference  35  is disposed on top of stapling head  600 , with flaps  32  held by spring  200  against knife  620  within knife cavity  630 . 
         [0060]    Referring now to  FIG. 9 , a schematic cross-sectional partial view of a portion of circular stapler  500  performing anastomotic joining of tubular tissues T 1  and T 2  is presented. Anvil  1000  is shown disposed within tubular tissue T 1  and connected to stapling head  600  via moveable shaft  1040 . Stapling head assembly  600  is shown disposed within tubular tissue T 2  and supported on support shaft assembly  700 . For simplification, the mechanism of staples  110  deployment and mechanism of deploying tissue cutting concentric knife  620  are not shown. 
         [0061]    Anvil  1000  is shown with an optional buttress  12 , which is similar to buttress  10  described above, similarly deployed on anvil  1000  using spring  201  disposed in anvil cavity  631  and immobilizing flaps  33  in anvil cavity  631 . Optional buttress  12  is deployed in a process similar to process described above for buttress  10 , whereby deployment tool  100  is used to deploy optional buttress  12  onto anvil  1000 . Deployment tool  100  is axially aligned and abutting anvil  1000 , with optional buttress  12  positioned between and compressed by distal end  111  of deployment tool  100  and anvil  1000 . Spring  201  is moved into anvil cavity  631 , bending flaps  33  into anvil cavity  631 . Spring  201  expands radially and presses flaps  33  against anvil cavity  631 . Thus spring  201  immobilizes optional buttress  12 , if installed, on anvil  1000  by pressing flaps  33  and holding flaps  33  against anvil cavity  631 . Optionally, deployment tool  100  has a central axial opening (not shown) in distal end  111  of plunger  135 , specifically in stem  135  and piston  137  in order to accommodate anvil pin (not shown). 
         [0062]      FIG. 9  shows anvil  1000  and stapling head  600  approximated, compressing between them tissue T 1  and T 2  as well as a portion of buttress  10  and a portion of optional buttress  12  disposed inside tubular tissues T 2  and T 1  respectfully. 
         [0063]    Referring now to  FIG. 10 , a schematic cross-sectional partial view of a portion of circular stapler  500  performing anastomotic joining of tubular tissues T 1  and T 2  is presented with staples  1010  fired thus establishing a stapled joint between tissues T 1  and T 2  with staples  1010  concentrically arranged in one or more concentric rows around tissue donut or cut-out  1020 . As shown, upon firing of the circular stapler  500 , central portion of tubular tissues T 1  and T 2  is severed by circular knife  620 , forming tissue cut-out  1020 . At the same time staples  1010  are deployed joining tissues T 1  and T 2  as well as buttress  10  and optional buttress  12  to tissues T 1  and T 2 , with buttress  10  inside tubular tissue T 2  and optional buttress  12  inside tubular tissue T 1 . As circular knife  620  is deployed, it also severs a central portion  32   a  of buttress  10  approximately corresponding to flaps  32  and also severs a central portion  33   a  of optional buttress  12  approximately corresponding to flaps  33 . 
         [0064]    After deploying staples and cutting out tissue cutout  1020 , circular stapler  500  is withdrawn. As shown in  FIG. 11 , this completes anastomotic joint of tissues T 1  and T 2  with the joint reinforced by remaining portion of buttress  10  inside tubular tissue T 2  and remaining portion of optional buttress  12  inside tubular tissue T 1 . 
       Dimensions 
       [0065]    Buttress  10  can be preferably made of absorbable materials such as natural polymers, polysaccharides, proteins, or the like, including collagen, ORC, Extra-Cellular Matrix, etc. Synthetic polymers can also be used. Buttress  10  can also be made of non-absorbable materials. Buttress  10  can also be made of composites which can include both absorbable and non-absorbable materials. Buttress  10  can also incorporate various medically useful agents, including anti-infective agents, tissue healing agents, growth factors, and the like. 
         [0066]    The thickness of buttress  10  is from about 0.1 mm to about 3 mm, such as 0.3 mm, 0.5 mm, 1 mm, 2 mm. The diameter of buttress  10  ranges from about 10 mm to about 30 mm, such as 20 mm, 25 mm, 28 mm. Distance D is from 1 mm to 8 mm, such as 2 mm, 3 mm, 4 mm. Slits  30  are from zero to 1 mm wide such as 0.1 or 0.3 mm wide. The diameter of preferably centrally circular aperture  20  is about 2 mm to 10 mm, such as 3 mm. End apertures  40  preferably have circular diameters from about 0.2 mm to about 2 mm, such as 0.5 mm, 1 mm, 1.5 mm. The slits are preferably evenly spaced. 
         [0067]    Spring  200  is formed of flat material, such as stainless steel metal, tightly wound into a cylinder, with metal thickness from about 0.1 mm to about 0.8 mm, such as 0.3 mm, and spring height from about 2 mm to about 10 mm, such as 5 mm. Spring  200  external diameter  230  is between 14.1 mm and 21.2 mm and internal diameter  235  is between 11.6 mm and 20.9 mm  235  (depends on metal thickness and deployment tool  100  dimensions). 
         [0068]    Cylindrical body  110  of deployment tool  100  has cylindrical opening  115  with diameter between 14 mm to 29 mm. Cylindrical body  110  in some embodiments has external diameter substantially equal or close to stapling head diameter as shown in  FIGS. 6A, 6B, 7A, 7B . In alternative embodiments, as shown in  FIGS. 6C, 7C, 7D , cylindrical body  110  has external diameter selected so that cylindrical body  110  can fit within knife cavity  630 . Wall  120  has thickness is from about 0.5 mm to about 4 mm, such as 1 mm, 2 mm, 3 mm. 
         [0069]    Spring  200  external diameter  230  is sized to enable positioning of spring  200  within stapling head  600  cavity  630  as well as within cylindrical opening  115  or inside cylindrical body  110  in a compressed form. 
         [0070]    The inventors have surprisingly discovered that the presence of end apertures  40  improved performance and prevented damage to buttress  10  during deployment, preventing propagation of cracks in the buttress. 
         [0071]    Buttress  10  had the following dimensions: diameter 25 mm and 0.25 mm thick made of multilayer extra cellular matrix (ECM) derived from porcine soft tissue having 8 flaps  32  formed by 8 slits having distance D=4 mm, Slits  30  length of 6 mm, aperture  20  diameter 3 mm, end apertures  40  of diameter 1.2 mm. Comparative buttress was identical but had no end apertures  40 . 
         [0072]    Spring  200  was made of stainless steel film having 0.5 inch width, 4.4 inch length, 0.006 inch thickness and turned 2.5 times. 
         [0073]    Deployment tool  100  was used to deploy buttress  1   o  onto stapling head  600 . 
         [0074]    The inventors have discovered that buttress  10  having end apertures  40  did not exhibit any cracks (before and after stapling), while comparative buttress was identical but had no end apertures  40 , showed cracks that propagated from the connection point between the leaflets into the stapled surface (distance D in  FIG. 2 ) and therefore failed. 
         [0075]    While the invention has been described above with reference to specific embodiments thereof, it is apparent that many changes, modifications, and variations can be made without departing from the inventive concept disclosed herein. Accordingly, it is intended to embrace all such changes, modifications, and variations that fall within the spirit and broad scope of the appended claims.