Abstract:
A surgical staple for use in creating an everted anastomosis of at least two anatomical structures includes a bendable staple body. At least two everting elements protrude from the staple body. Spacing elements and a penetrating element also are provided. In use, the everting elements and spacing elements are apposed, and inner layers of the anatomical structures are held together to form an everted anastomosis. The everting platforms are disposed on an outer radius of the closed staple, and the penetrating element is disposed on a different, inner radius, to ensure that the penetrating element is excluded from the lumen of the anastomosis. Embodiments of the invention substantially ensure intima-to-intima approximation completely circumferentially at the anastomotic site, with no portion of cut tissue edges, suture or staple exposed to the lumen of the anastomosis. Cut tissue edges, as well as the staple, are completely extra-lumenal. Related methods are also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    The subject matter of this application is related to the subject matter of commonly assigned U.S. applications Ser. Nos. 60/187,428, filed Mar. 7, 2000 and 60/201,594, filed May 3, 2000, both of which are incorporated herein by reference and priority to which is claimed under 35 U.S.C. §119(e). 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of Invention  
           [0003]    The invention relates to devices and methods for anastomosing two or more anatomical structures, such as vascular structures. Embodiments according to the invention are desirable in both minimally invasive and conventional surgical situations. Certain embodiments have particular application to minimally invasive direct coronary artery bypass (MIDCAB) and off-pump (OPCAB) procedures, for example.  
           [0004]    2. Description of Related Art  
           [0005]    Surgical connections (anastomoses) between two tubular structures of soft tissue (e.g. blood vessels) typically are fashioned with “linkage” devices, such as flexible suture or rigid staples. Such anastomoses involve surgical incisions of the two soft tissue structures, which result in cut edges. These edges ideally are excluded from the inside channel (lumen) of the two joined structures. Ideally, the linkage devices are also excluded from the lumen.  
           [0006]    The suture- and staple-type linkage devices of the prior art, however, do not always achieve the above-described ideal; cut tissue edges and the linkage devices themselves sometimes are exposed to the lumen. See FIGS.  1 A- 1 D, for example, which show unpredictable eversion and exclusion of cut edges  10  (of ends  20 ,  30  of anatomical structures  40 ,  50 ) and suture  60  from lumen  70  when sutures alone are used, as in the prior art.  
         SUMMARY OF THE INVENTION  
         [0007]    In view of these and other disadvantages, a need exists for devices and methods that consistently, predictably and reliably evert the edges of an e.g. circumferential anastomosis between two tubular anatomical structures, e.g. a vascular anastomosis between the left internal mammary artery and the left anterior descending coronary artery. Such devices and methods can be used alone, or in conjunction with a biological adhesive product, suture, or other supplemental products or devices. They can be part of a sutured or stapled anastomosis, i.e. an anastomosis using one or more sutures and/or staples in combination with the devices of the invention.  
           [0008]    The ultimate purpose, according to embodiments of the invention, is to substantially ensure inner-layer-to-inner-layer (e.g. intima-to-intima) approximation completely circumferentially at the anastomotic site, with no portion of the cut edges of the tissues or suture or staple exposed to the lumen of the anastomosis. Instead, embodiments of the invention substantially ensure that the cut edges of the tissues, as well as the linkage device, are completely extra-lumenal. With such embodiments, the entire circumference of both structures of the anastomosis is completely everted.  
           [0009]    Embodiments of the invention provide a number of advantages. For example, the invention provides a more precise, completely everted anastomosis more predictably than heretofore possible with staples or suture alone. Embodiments of the invention are believed to result in a higher patency rate in vascular anastomoses, by eliminating cut edges of tissue or foreign bodies (e.g. sutures or staples) from the lumen. Such tissue edges or foreign bodies, if left exposed to the lumen, can threaten the patency of the anastomosis by allowing thrombus (clot) formation and/or fibrosis or intimal hyperplasia (scarring), ultimately resulting in stenosis (narrowing) or occlusion. Embodiments of the invention, on the other hand, cause immediate and long-term improvements in patency and therefore quality of life and longevity.  
           [0010]    Further, embodiments of the invention allow a smaller number of anastomotic eversion devices to be used, e.g. in conjunction with a biological adhesive or equivalent. Such hybrid procedures allow for a simpler, more expeditious anastomosis, with either conventional or minimally invasive techniques, with or without the aid of cardiopulmonary bypass.  
           [0011]    Still further, according to embodiments of the invention, everting platforms on an outer radius of a closed everting staple assure that a penetrating element of the staple is excluded from the lumen, because the penetrating element is on a different, inner radius. Spacing elements according to the invention assure a space between everting platforms of the staple in a closed configuration of the staple, negating any tissue necrosis at the level of intima-to-intima approximation.  
           [0012]    Penetrating and spacing elements according to embodiments of the invention may cause tissue damage, but such damage is outside of the anastomosis, i.e. it is at or near the inner radius of the closed staple. Nevertheless, spacing elements and/or penetrating elements according to such embodiments have small surface area, to minimize tissue necrosis. To effect parallel alignment of the everting platforms, the staple is “scissored” in the closed position thereof. One of the everting platforms is offset accordingly.  
           [0013]    By providing two everting platforms on a single piece of wire or other material constituting the staple, according to embodiments of the invention, the need to deliver an opposing everting platform from an opposite side of an anastomosis is eliminated. Other features and advantages according to embodiments of the invention will become apparent from the remainder of this application. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    Embodiments of the invention will be described with reference to the figures, in which like reference numerals refer to like elements and in which:  
         [0015]    FIGS.  1 A- 1 D show one type of prior art anastomosis technique using a suture alone, with unpredictable eversion and exclusion of cut edges and suture from the lumen;  
         [0016]    [0016]FIG. 2 is a panoramic view of an open staple according to an embodiment of the invention, with an everting platform, offset everting platform, two spacing elements and penetrating element as shown;  
         [0017]    [0017]FIG. 3 is a panoramic view of a closed, “scissored” staple with two radii and two axes according to an embodiment of the invention. More specifically, FIG. 3 shows an outer radius of the illustrated everting platforms, an inner radius of the spacing and penetrating elements, and side-by-side offset axes of the closed staple;  
         [0018]    [0018]FIG. 4 is a side view of a staple according to an embodiment of the invention, showing the penetrating element, spacing elements, and everting platforms;  
         [0019]    [0019]FIG. 5 is a side view of closed staple enclosing tissue, according to an embodiment of the invention, showing the penetrating element, everting platforms and spacing elements;  
         [0020]    [0020]FIG. 6 is a side view showing the inner radius of the spacing and penetrating elements and the outer radius of the everting platforms;  
         [0021]    [0021]FIG. 7 is an end view of a closed staple enclosing tissue, according to an embodiment of the invention, showing the penetrating element, everting platforms and spacing elements;  
         [0022]    [0022]FIG. 8 is an inside view of a open staple, according to an embodiment of the invention, showing the penetrating element, everting platforms and spacing elements, and the direction of closure of the staple;  
         [0023]    [0023]FIG. 9 is an outside view of an open staple, according to an embodiment of the invention, showing the penetrating element, everting platforms and spacing elements, and the direction of closure of the staple;  
         [0024]    [0024]FIG. 10 is a perspective view of a staple and an eversion platform, according to an embodiment of the invention;  
         [0025]    [0025]FIG. 11 is a side view of an eversion platform with overhanging collar, according to an embodiment of the invention;  
         [0026]    [0026]FIG. 12 is a side, cross-sectional view of a stapled anastomosis in a staple-open, platforms-apart configuration;  
         [0027]    [0027]FIG. 13 is a side, cross-sectional view of a stapled anastomosis in a staple-closed, platforms-apposed configuration;  
         [0028]    [0028]FIG. 14 is a side view showing the inner radius of the staple and the outer radius of the eversion platforms; and  
         [0029]    [0029]FIG. 15 is a panoramic view of an end-to-side anastomosis in a staple-closed configuration. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0030]    A first embodiment of surgical staple  100  for creating a completely everted anastomosis is shown in FIGS.  2 - 9 . Staple body  110  of surgical staple  100  is constructed to bend, e.g. at  120  in FIG. 3. At opposite ends of staple body  110 , staple  100  includes everting platforms or elements  130 ,  140  that protrude from staple body  110 . Everting platform  130  is centered with respect to longitudinal axis  145  of staple body  110 . As illustrated, a central portion  146  of everting platform  130  is connected to the very end of staple body  110 . Everting platform  140 , on the other hand, is connected to staple body  110  at its end  148 , not at a central portion thereof. Thus, as shown in e.g. FIGS.  8 - 9 , everting platforms  130 ,  140  are offset with respect to each other, in a transverse direction with respect to axis  145 .  
         [0031]    Surgical staple  100  also includes first spacing element  150 , disposed adjacent staple body  110  at the very end thereof. Specifically, spacing element  150  is adjacent to longitudinal axis  145  thereof and above everting platform  130 , as viewed in e.g. FIGS. 2 and 8. Staple  100  also includes second spacing element  160 , disposed along staple body  110  at the opposite end thereof and generally in line with longitudinal axis  145  thereof. Spacing elements  150 ,  160  are closer to the middle of staple body  100  than are everting platforms  130 ,  140 . Spacing elements  150 ,  160  can be generally tapered, as shown at e.g.  165  in FIGS. 2 and 8. Of course, other placements and shapes of spacing elements  150 ,  160  are contemplated.  
         [0032]    Penetrating element  170  is constructed to penetrate the anatomical structures being anastomosed, in a manner to be described, and is disposed at one end of staple body  110 . Penetrating element  170  is disposed generally along longitudinal axis  145  of staple body  110  and is generally perpendicular or transverse, or otherwise angled, to it.  
         [0033]    Staple  100  is constructed to bend from the straight or non-use or open configuration illustrated in FIGS.  2  and/or  4  to the bent or “scissored” or closed configuration of FIG. 3. In the FIG. 3 configuration, everting platforms  130 ,  140  are disposed generally parallel to each other on the same side of penetrating element  170 , e.g. the underside as viewed in FIG. 3. Additionally, everting platforms  130 ,  140  are apposed, as are spacing elements  150 ,  160 .  
         [0034]    As illustrated in FIG. 3, spacing elements  150 ,  160  and penetrating element  170  generally define elevation line  180 . Everting platforms  130 ,  140  generally define elevation line  190 . Lines  180 ,  190  define distances from bend  120  that can be considered inner and outer radii, respectively. Because line  180  is closer to bend  120 , line  180  can be considered to define an inner radius of staple  100 . Similarly, line  190  can be considered to define an outer radius of staple  100 . Additionally, FIG. 3 illustrates side-by-side offset axes  200 ,  210  of staple  100 . Axes  200 ,  210  are offset from each other in two dimensions, e.g. a first dimension as viewed in the direction of lines  180 ,  190 , and a second dimension as viewed in the direction of everting platforms  130 ,  140 , in FIG. 3. In its closed configuration, staple  100  is bent in a “U” shape to form two legs  220 ,  230  separated by bend  120 . Legs  220 ,  230  are disposed along axes  200 ,  210  and thus are offset from each other in two dimensions.  
         [0035]    FIGS.  5 - 7  show staple  100  in use. As shown, staple  100  joins inner layer (intima)  240  of anatomical structure  250  to inner layer (intima)  260  of anatomical structure  270 . Staple  100  keeps lumen  280  between anatomical structures  250 ,  270  free of exposure to cut tissue edges  290 , ends  300 ,  310  of anatomical structures  250 ,  270 , and all portions of staple  100  itself, including penetrating element  170 . Lumen  280  is also free of suture and other foreign bodies. Thus, staple  100  causes immediate and long-term improvements in the patency of the anastomosis by reducing the likelihood of clot formation, scarring, stenosis and other complications.  
         [0036]    When staple  100  is in its closed configuration around cut ends  300 ,  310  of anatomical structures  250 ,  270 , spacing elements  150 ,  160  are in an apposed relationship and cut ends  300 ,  310  are held together between spacing elements  150 ,  160 . Additionally, everting platforms  130 ,  140  are in an apposed relationship, with cut ends  300 ,  310  held together between everting platforms  130 ,  140 . Penetrating element  170  penetrates ends  300 ,  310 . The distance between apposed spacing elements  150 ,  160  is less than the distance between apposed everting platforms  130 ,  140 , as shown. As shown in e.g. FIG. 6, apposed spacing elements  150 ,  160  and/or penetrating element  170  define inner radius  180  of closed staple  100 , and apposed everting platforms  130 ,  140  define outer radius  190  of closed staple  100 , radii  180 ,  190  being considered to originate at bend  120  in staple  100 . Because penetrating element  170  is on the different, inner radius  180 , it is generally assured that penetrating element  170  is excluded from lumen  280 .  
         [0037]    As shown in FIGS.  8 - 9 , everting platform  140  moves laterally or transversely with respect to staple body  110  as staple  100  is closed, such that the direction of closure  320  is at an angle to staple body  110 . A method of bending a surgical staple according to an embodiment of the invention includes moving everting platform  140 , disposed at one end of staple  100 , to be parallel to and adjacent to everting platform  130  disposed at an opposite end of staple  100 . Spacing element  160  disposed at one end of staple  100  becomes apposed to spacing element  150  disposed at the opposite end of staple  100 . Spacing elements  150 ,  160  are disposed adjacent to and generally parallel to penetrating element  170 . Everting platform  140  moves in direction of closure  320  to its disposition parallel to and adjacent to everting platform  130 . Direction of closure  320  is disposed at an angle, e.g. about 15° to about 20°, to longitudinal axis  145  extending between everting platforms  130 ,  140 . Thus, everting platforms  130 ,  140  are moved from an offset configuration, illustrated in FIG. 8, in which platforms  130 ,  140  are offset from each other along their respective longitudinal axes, to a non-offset configuration, illustrated in e.g. FIG. 3, in which everting platforms  130 ,  140  are aligned with each other.  
         [0038]    Turning to FIGS.  10 - 15 , staple devices according to embodiments of the invention include two main parts. The first part is staple  400 , defining a generally curved shape and supporting a fixed eversion platform  410  securely and immovably affixed thereto, according to one embodiment. Staple  400  can be a free-standing staple, or attached to a suture or other delivery system, for example. The second part is free eversion platform  420 , which is supportable by staple  400  and slidable relative thereto in a “threaded” relationship.  
         [0039]    Both staple  400  and free eversion platform  420  preferably have a substantially “D”-shaped cross section  430 , to predictably orient eversion platform  420 . Of course, other cross-sectional shapes of the staple and free eversion platform are contemplated, according to embodiments of the invention. Staple  400  and platform  420  preferably are made of a biocompatible material. At least the staple is malleable, according to a preferred embodiment, so that it can be crimped into a closed position with a closing or crimping device. According to other embodiments, described below, a memory metal eliminates or reduces the need for a separate closing device.  
         [0040]    Free eversion platform  430  generally comprises two parts: collar or spacing element  440  and eversion body or platform  450 . Eversion platform  450  preferably is made of a biocompatible material similar to staple  400 . However, it is substantially non-deformable, according to this embodiment. Collar  440  slightly overhangs eversion platform  420  in the axis of staple  460 , as indicated at  460  in FIG. 11. Overhang  460  substantially prevents apposing eversion platforms  410 ,  420  from crushing cut ends  470 ,  480  of vascular or other structures  490 ,  500  in the anastomosis, by keeping them slightly separated from one another in the closed position. Thus, any tissue in the anastomosis is approximated without being strangulated. Additionally, lumen  510  is kept free of exposure to cut tissue edges  520 ,  530 , staple  400 , eversion platforms  410 ,  420 , suture, or other structures that might threaten the patency of the anastomosis.  
         [0041]    According to embodiments of the invention, either eversion platform  410 ,  420  illustrated in e.g. FIG. 10 can be fixed or free, or both can be free. Everting staple  400  likely is easier to deploy, however, if one platform is fixed and the other is free, as illustrated. Structurally, platforms  410 ,  420  are generally identical according to one embodiment.  
         [0042]    According to the illustrated embodiment, fixed eversion platform  410  is nearer trailing end  535  of staple  400 , especially when it is to be deployed via a suture or other delivery mechanism. Suture can be attached to the leading end  537  of the staple, for example, and free eversion platform  420  deployed after engaging and penetrating the two vascular or other structures  490 ,  500  with staple  400 . The body of staple  400 , or a portion thereof, thus is a penetrating element. According to one embodiment, free eversion platform  420  is threaded over a needle and suture, is advanced along the suture to staple  400 , and then is advanced to a desired position along staple  400  as shown in e.g. FIG. 12. A closing/crimping device or other means then brings the paired eversion platforms  410 ,  420  into final juxtaposition to each other as staple  400  is closed, in the manner of e.g. FIG. 13. Eversion platforms  410 ,  420  are the fulcrum for closing staple  400 .  
         [0043]    Of course, two separate free eversion platforms  410  can be employed, with neither affixed to staple  400  at least until after staple  400  engages the two vascular structures  490 ,  500 . The free eversion platforms slide over suture and/or the respective ends of staple  400 , while staple  400  is still in an open position. According to this embodiment, and/or according to those described earlier, suture can be attached to either or both ends of staple  400 .  
         [0044]    As shown in FIG. 14, collars  440  and eversion bodies  450  of eversion platforms  410 ,  420  define inner radius  540  and outer radius  550 , respectively, of staple  400 . FIG. 15 shows multiple closed staples  400  disposed in a radial plane, with eversion bodies  450  disposed in the anastomotic plane, in an end-to-side anastomosis.  
         [0045]    According to embodiments of the invention, a plurality of everting staples can be employed to create a single anastomosis, as shown in FIG. 15, by themselves or optionally in combination with supplemental adhesives, suture, etc. to reduce the number of staples needed. Of course, each eversion platform and staple can be appropriately dimensioned to suit a particular patient, surgical procedure, surgical environment or other factor. Device pairs or combinations of different types or sizes can be used in the same anastomosis, if desired.  
         [0046]    As referenced earlier, staple devices according to the multiple embodiments of the invention can be free-standing staples and/or can be connected to a delivery system for the staple device. For example, a flexible element such as suture, suture wire, wire or equivalent (not shown) can extend from a separation point at or near the penetrating element and terminate at a needle (not shown). Staple devices according to embodiments of the invention preferably are made of a biocompatible material, e.g. titanium, stainless steel, nitinol, etc. Such staple devices preferably are malleable, for crimping into a closed position with a closing or crimping device, and/or are constructed of a memory material or other material that can be induced to deform into a desired configuration, e.g. a closed configuration. In the case of a memory material such as nitinol, the staple device can be formed in the closed position, sprung open and delivered to the tissues, and then released from an e.g. delivery system after springing back into a closed position. Such memory material eliminates the need for complicated crimping tools, which are complex and potentially damaging to delicate tissues during deployment due to their bulk and the ergonomics required to deploy them.  
         [0047]    Spacing elements according to embodiments of the invention substantially prevent the apposing everting platforms from crushing the cut ends of the vascular or other structures in the anastomosis, by keeping the everting platforms slightly separated from one another in the closed position of the staple. Thus, any tissue in the anastomosis is approximated without being strangulated, consistent with the surgical adage: “approximate, don&#39;t strangulate.” If the eversion platforms were not kept slightly apart in the closed position, the tissue engaged between them could be crushed to death (necrose) closer to the lumen. With particular reference to e.g. FIGS.  5 - 7 , but also with reference to other embodiments, tissue is engaged in the closed staple with more tissue compression at the spacing elements and less tissue compression at the offset everting platforms. Tissue engagement and compression in this manner accomplishes approximation without strangulation, ensuring viability of the tissue at the most critical point of the anastomosis, namely, the juncture of the two structures being anastomosed.  
         [0048]    As referenced above, a plurality of the everting staple devices described herein can be used in a single anastomosis, or a single device can be used. In the case of a single device, one or more sutures, one or more conventional or other type of staples, one or more areas of biological adhesive and/or other means additionally can be used, e.g. at least directly opposite one or each staple device described herein, to complete the anastomosis. In the case of multiple staple devices, whatever the type, it is desirable to space each device at selected points around the circumference of the anastomosis, e.g. at quadrant points (e.g. 12 o&#39;clock, 3 o&#39;clock, 6 o&#39;clock and 9 o&#39;clock positions) or half points (e.g. 12 o&#39;clock and 6 o&#39;clock positions).  
         [0049]    Non-everting staple devices can be used at e.g. the heel and toe of an anastomosis formed using a longitudinal (i.e. in the direction of blood flow) opening in the artery or other recipient vessel, and everting staple devices can be used along the sides of the anastomosis between the heel and toe. Such use of non-everting staple devices would reduce the possibility of compromising the circumference of the recipient vessel at the heel and toe. Use of adhesive, suture, or other connection devices or methods in addition to or instead of everting staples can also reduce possible complications and/or the number of everting staple devices needed to form an anastomosis. Staple devices all of the everting type can be used more readily with a transverse (i.e. in the direction perpendicular to blood flow) opening in the recipient vessel.  
         [0050]    Of course, each staple can be appropriately dimensioned to suit a particular patient, surgical procedure, surgical environment or other factor. Devices of different sizes can be used in the same anastomosis, if desired.  
         [0051]    In use, according to one embodiment, the surgeon or other medical professional penetrates the walls of the vascular or other anatomical structures using one or more needles attached to e.g. suture or other material. The suture, in turn, is attached at or near e.g. a penetrating element of the staple device or to another suitable point at, on, or in association with the staple device. According to alternative embodiments, the staple is a free-standing staple and/or includes delivery mechanisms other than suture and one or more needles.  
         [0052]    While the invention has been described with respect to specific embodiments, the invention should not be considered limited to the specific embodiments illustrated and described herein. For example, embodiments of the invention apply not only to anastomoses of vascular structures in e.g. minimally invasive thoracic surgical situations, but also to conventional surgical techniques and to anatomical structures other than vascular structures. Embodiments of the invention apply to anastomosing prosthetic tubular grafts to vascular structures or to each other. Specific features described with respect to one embodiment are also to be considered useable with the other embodiments disclosed and contemplated herein. Other modifications and changes are readily discernible from the specification and will be apparent to those of ordinary skill.