Abstract:
A surgical clip and method for anastomosing a gastrointestinal tract, the clip being formed at least partly of a shape memory alloy, the clip including: a first length of a wire defining a closed geometrical shape having a central opening; a second length of a wire defining a closed geometrical shape similar in configuration and magnitude to that of the first length of wire, wherein, when placed in side-by-side registration, the first and second lengths of wire fully overlap; an intermediate portion located between the first length of wire and the second length of wire, the intermediate portion formed of a shape memory alloy; a cutting element associated with the first length of wire; a counter element associated with the second length of wire and arranged for cutting engagement with the cutting element; wherein when at a first temperature or higher, the first and second lengths of wire are positioned in a side-by-side closed position and the shape memory alloy is in an elastic state, and further, when at a second temperature or lower, below the first temperature, the shape memory alloy is in a plastic state, thereby enabling the first and second lengths of wire to be moved into and to retain a spaced apart position, and upon heating of the clip to a temperature at least equal to the first temperature, the first and second lengths of wire return to the side-by-side closed position, thereby to apply a compressive force to tissue located therebetween.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of surgical clips generally, and, in particular, to the field of surgical clips formed of a shape memory alloy. 
     BACKGROUND OF THE INVENTION 
     Several methods are known in the art for joining portions of hollow organs, such as the gastrointestinal tract. These include threads for manual suturing, staplers for mechanical suturing, and compression rings and clips. 
     While manual suturing is universally known and relatively inexpensive, the degree of success depends considerably on the skill of the surgeon. Another disadvantage is that post-operative complications are common. Further, suturing an organ results in lack of smoothness of the tissue therein, which, when the sutured organ is part of the gastrointestinal tract, hampers peristalsis in the sutured area. Finally, suturing is both labor and time consuming. 
     Staplers for mechanical suturing ensure a reliable joining of tissue and enable the time needed for surgery to be reduced, compared with manual suturing. However, due to the facts that such staples are not reusable and that a great many types and sizes are required, the price of staples is high. Also, after healing, metal staples remain in place along the perimeter of the which reduces elasticity of the junction and adversely affects peristalsis when the sutured organ is part of the gastrointestinal tract. 
     Junctions using compression devices such as rings and clips ensure the best seal and post-operative functioning of the organs. Two types of compression devices are known, namely, rings made of resorption plastics and clips made of memory alloys. Plastic rings are cumbersome and expensive. Also, the compression force is applied only momentarily at the junction and is reduced as the tissue is crushed. Clips made of shape memory alloys enable portions of tissue to be pressed together when equilibrium with body temperature is reached, whereat, due to the inherent properties of the alloys, the clips resume their memorized shape. 
     Development of clips made of memory alloy materials has increased recently, as they have many advantages over other devices. Their design is simple, they are cheap, they are small in size and possess universal qualities, and they are self-evacuated from the gastrointestinal tract. 
     It is known in the art to provide a surgical fastening clip which applies a clamping force to a site, such as a blood vessel, thereby reducing its cross-sectional area. It is also known to provide a surgical fastening clip formed of a shape memory alloy which deforms to a closed configuration when heated, such that the clamping force applied thereby is increased as it is heated. For example, U.S. Pat. No. 5,171,252 discloses a surgical fastening clip formed of a shape memory alloy; the device disclosed therein includes separate legs which close tightly around a site. Such a device is limited in its uses, such as for clamping blood vessels, and is not suitable for joining portions of the gastrointestinal tract. 
     EP 0,326,757 discloses a device for anastomosing a digestive tract, which includes a plurality of U-shaped retaining clips disposed around a soluble support tube. The tube is positioned inside portions of the digestive tract to be joined, and includes an outer groove around which are disposed the U-shaped retaining clips. The retaining clips are made of a shape memory alloy such that the open ends thereof close at a predetermined temperature, thus joining ends of the digestive tract. Once the ends of the digestive tract have been joined, the tube is dissolved. Such a device is disadvantageous in that its use requires that a plurality of clips to be properly positioned simultaneously. Also, there is no assurance that the resulting junction will be smooth, due to the plurality of sites of the digestive tract joined by the plurality of clips. 
     SU 1,186,199 discloses a memory alloy clip consisting of two parallel coils to be used for joining portions of a hollow organ, such as an organ of the gastrointestinal tract. The portions of the organ to be joined are aligned, and each of the plastic coils is introduced through a puncture formed in the wall of one of the portions. The coils are positioned such that, when heated, they compress the aligned walls therebetween, thus maintaining the portions of the walls held within the loops of the coils adjacent each other. Thereafter, incisions are made through the portions of the walls held within the loops of the coils, such that a passageway is created between the two organ portions. The punctures in the organ walls must then be surgically sewn closed with interrupted surgical sutures. 
     A major disadvantage of known memory alloy clips is that they permit compression of only approximately 80-85% of the junction perimeter, thus requiring additional manual sutures, which reduce the seal of the junction during the healing period and its elasticity during the post-operative period. Also, this additional suturing is problematic inasmuch as it has to carried out across a joint which includes a portion of the clip, thereby rendering difficult the sealing and anastomosis of the organ portions. Furthermore, once in place, clips according to the prior art require further surgery to be performed, namely, incisions through tissue so as to create a passageway between the two organ portions which have been joined by the clip. 
     There is thus a need for a surgical device which facilitates compression of substantially the entire perimeter of the junction between the organ portions being joined, which would obviate the need for additional manual sutures and which ensure the smooth seal of the junction during the healing period and its elasticity during the post-operative period. Additionally, there is a need for a surgical device which, once in place, would enable a passageway to be created between the two organ portions which have been joined together, without requiring further surgery to be performed on the organ. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide an improved surgical clip formed of a shape memory alloy, and a method of joining two portions of a hollow organ, which overcome disadvantages of prior art. 
     There is thus provided, in accordance with a preferred embodiment of the present invention, a surgical clip formed at least partly of a shape memory alloy, the clip including: a first length of a wire defining a closed geometrical shape having a central opening; a second length of a wire defining a closed geometrical shape similar in configuration and magnitude to that of the first length of wire, wherein, when placed in side-by-side registration, the first and second lengths of wire fully overlap; an intermediate portion located between the first length of wire and the second length of wire, the intermediate portion formed of a shape memory alloy; a cutting element associated with the first length of wire; a counter element associated with the second length of wire and arranged for cutting engagement with the cutting element; wherein when at a first temperature or higher, the first and second lengths of wire are positioned in a side-by-side closed position and the shape memory alloy is in an elastic state, and further, when at a second temperature or lower, below the first temperature, the shape memory alloy is in a plastic state, thereby enabling the first and second lengths of wire to be moved into and to retain a spaced apart position, and upon heating of the clip to a temperature at least equal to the first temperature, the first and second lengths of wire return to the side-by-side closed position, thereby to apply a compressive force to tissue located therebetween. 
     Additionally in accordance with a first embodiment of the present invention, the surgical clip further includes apparatus for pressing the cutting element into cutting engagement with the counter element wherein, when at the first temperature or higher, the apparatus for pressing presses the cutting element into cutting engagement with the counter element. 
     In accordance with an alternative embodiment of the present invention, the surgical clip further includes apparatus for pressing the cutting element into cutting engagement with the counter element wherein, when at the first temperature or higher, the apparatus for pressing is actuatable by an outside force. 
     Further in accordance with an embodiment of the present invention, the geometrical shape of the surgical clip is a circle. 
     Yet further in accordance with an alternative embodiment of the present invention, the geometrical shape of the surgical clip is an ellipse. 
     In accordance with an embodiment of the present invention, the first length of wire and the second length of wire are defined by a continuous coil. 
     Still further in accordance with an alternative embodiment of the present invention, the first length of wire and the second length of wire are two distinct lengths of wire, each defining a closed geometrical shape. 
     Still further in accordance with a preferred embodiment of the present invention the counter element also includes a cutting element. 
     According to the present invention, there is also provided a method for anastomosing a gastrointestinal tract, the method including the following steps: (a) providing a surgical clip formed at least partly of a shape memory alloy, the clip including: a first length of a wire defining a closed geometrical shape having a central opening; a second length of a wire defining a closed geometrical shape similar in configuration and magnitude to that of the first length of wire, wherein, when placed in side-by-side registration, the first and second lengths of wire fully overlap; an intermediate portion located between the first length of wire and the second length of wire, the intermediate portion formed of a shape memory alloy; a cutting element associated with the first length of wire; a counter element associated with the second length of wire and arranged for cutting engagement with the cutting element; (b) cooling at least the intermediate portion to a temperature below a lower phase transition temperature thereof, whereat the intermediate portion is in a plastic state, thereby enabling the first and second lengths of wire to be moved into and to retain a spaced apart position; (c) manually moving apart the first and second lengths of wire; (d) drawing together portions of the gastrointestinal tract wherein anastomosis is desired, such that the portions are in adjacent, side-by-side relationship, at least one of the portions being open-ended; (e) surgically sealing the open ends of the portions of the gastrointestinal tract; (f) forming punctures in walls of the gastrointestinal tract adjacent to each other, the puncture being adjacent; (g) introducing the clip through the punctures, such that the a wall of each portion of the gastrointestinal tract is situated between the first and second lengths of wire; (h) maintaining the relative positions of the portions of the gastrointestinal tract and the clip in relation thereto, while raising the temperature of at least the intermediate portion to a temperature above its upper phase transition temperature, whereat the intermediate portion is in an elastic state, thereby causing the first and second lengths of wire to attain the side-by-side registration, thereby to apply a compressive force to tissue located therebetween. 
     Additionally in accordance with a preferred embodiment of the present invention, according to the method, in step (h), the temperature of the clip is raised to the temperature above its upper phase transition temperature by the heat of the gastrointestinal tract. 
     Further in accordance with a preferred embodiment of the present invention, according to the method, the clip further including apparatus for pressing the cutting element into cutting engagement with the counter element wherein, when at the upper phase transition temperature or higher, the apparatus for pressing presses the cutting element into cutting engagement with the counter element, thereby creating an opening in the tissue located between the first and second lengths of wire, thereby creating initial patency of the gastrointestinal tract; and the method includes after step (h), the additional step of widening the opening. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be more fully understood and appreciated from the following detailed description, in which: 
     FIGS. 1A and 1B are pictorial illustrations of a surgical clip according to a first embodiment of the present invention, the clip being in an open configuration and a closed configuration, respectively; 
     FIGS. 2A and 2B are pictorial illustrations of a surgical clip according to a second embodiment of the present invention, the clip being in an open configuration and in a closed configuration, respectively; 
     FIG. 3A is a pictorial illustration of a surgical clip according to a third embodiment of the present invention, the clip being in an open configuration; 
     FIG. 3B is a side view of the surgical clip shown in FIG. 3A; 
     FIG. 3C is a side view of the surgical clip shown in FIG. 3B, the clip being in a closed configuration; 
     FIG. 3D is a side view of the surgical clip shown in FIG. 3C, wherein the cutting element and counter element are being pressed against each other; 
     FIGS. 4A and 4B are respective pictorial and side view illustrations of a surgical clip according to a fourth embodiment of the present invention, the clip being in an open configuration; 
     FIG. 4C is a side view of the surgical clip shown in FIG. 4A, the clip being in a closed configuration; 
     FIG. 4D is a side view of the surgical clip shown in FIG. 4C, wherein the cutting element and counter element are being pressed together; 
     FIG. 4E is a pictorial view of a surgical clip according to a fifth embodiment of the present invention, the clip being in an open configuration; 
     FIGS. 5A and 5B are pictorial illustrations of respective counter and cutting elements which may be employed in the surgical clip according to the embodiment shown in FIG. 4E; 
     FIG. 5C is a pictorial illustration of a cutting element and a corresponding counter element which may be employed in the surgical clip according to either of FIGS. 1A and 1B; 
     FIG. 5D is a pictorial illustration of a surgical clip in accordance with the present invention, wherein a further embodiment of a cutting element and counter element are employed; 
     FIGS. 5E,  5 F,  5 G,  5 H, and  5 I are further alternative embodiments of cutting elements and counter elements which may be employed in the surgical clip according to the present invention; 
     FIG. 6A is a pictorial illustration of a surgical clip according to a sixth embodiment of the present invention; 
     FIG. 6B is a side view illustration of the surgical clip shown in FIG. 6A, the clip being in a closed configuration; 
     FIGS. 6C, and  6 D are side view illustrations of the surgical clip shown in FIG. 6A, the clip being in a closed position, wherein the cutting element is being pressed into cutting engagement with the counter element and wherein the cutting element has been released from cutting engagement with the counter element, respectively; 
     FIG. 7A is a pictorial illustration of a hollow organ inside which there has been placed the surgical clip of FIGS. 1A and 1B, in accordance with the present invention, the surgical clip being in a plastic state; 
     FIG. 7B is a cross-sectional view, taken in the direction of line  7 B— 7 B, of the hollow organ and surgical clip shown in FIG. 7A; 
     FIG. 7C is a view of the hollow organ and surgical clip shown in FIG. 7A, the surgical clip being in an elastic state; and 
     FIG. 7D is a cross-sectional view, taken in the direction of line  7 D— 7 D, of the hollow organ and surgical clip shown in FIG.  7 C. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention seeks to provide a surgical clip, formed at least partly of a shape memory alloy, such as is known in the art, and which provides organ tissue compression along the entire periphery of the clip, thereby to ensure satisfactory joining or anastomosis of portions of an organ, and which provides apparatus for cutting a portion of tissue, whereby initial patency of the gastrointestinal tract is created. The present invention further seeks to provide a method for performing anastomosis of organ portions, such as those of the gastrointestinal tract, the method employing the clip of the present invention, and for cutting a portion of tissue, whereby initial patency of the gastrointestinal tract is created. 
     Referring now to the drawings, FIGS. 1A and 1B illustrate a surgical clip, referenced generally  10 , according to a first embodiment of the present invention, the clip  10  shown in respective open and closed configurations. Clip  10  is typically wire-like, formed at least partly of a shape memory alloy, and is of a coiled configuration so as to include a pair of loops  12  and  22 , having respective ends  14  and  24 . Each of loops  12  and  22  defines a complete circle from its end to a point  30  midway along the coil. Thus, the coil defines two complete circles from end  14  of loop  12  to end  24  of loop  22 . While the various embodiments of the clip of the present invention are illustrated as defining circular shapes, it will be appreciated by persons skilled in the art that the present invention may, alternatively, define any closed geometric shape, such as an ellipse. 
     At least an intermediate portion  13  of clip  10  is formed of a shape memory alloy such that, when cooled to below a predetermined temperature, the clip is in a plastic state, such that loops  12  and  22  may be moved apart, as to the position shown in FIG.  1 A. When heated to above the predetermined temperature, the clip  10  is in an elastic state, such that the loops  12  and  22  are adjacent each other, as in the position shown in FIG.  1 B. The change in temperature, as it affects the shape memory alloy, will be discussed further, with reference to FIGS. 7A-D. 
     Loops  12 ,  22  of clip  10  are provided with a pair of crossbars  16 ,  26 , respectively, which extend across respective loops  12 ,  22 . Crossbars  16  and  26  may be fastened to respective loops  12  and  22  by any suitable means. Crossbar  16  is provided with an aperture  18 , and crossbar  26  is provided with a hollow cutting element  20  having a blade portion  48  which circumscribes an aperture  28 . Blade portion  48  of cutting element  20  has a configuration and size relative to aperture  18  so as fit snugly therein (FIG.  1 B). Crossbar  16  extends between points  32  and  34  along the circle defined by loop  12 , and crossbar  26  extends between points  42  and  44  along the circle defined by loop  22 . The distance along loop  12  from point  30  to point  32  is the same as the distance along loop  22  from end  24  to point  42 . Similarly, the distance along loop  12  from end  14  to point  34  is the same as the distance along loop  22  from point  30  to point  44 . Thus, as shown in FIG. 1B, when loops  12  and  22  are adjacent, crossbars  16  and  26  overlie each other, and cutting element  20  is aligned with aperture  18 . While crossbars  16  and  26  are shown at a particular orientation relative to loops  12  and  22 , respectively, it will be appreciated by persons skilled in the art that any orientation whereby crossbars  16  and  26  overlie each other is possible, without departing from the scope of the invention. 
     As shown in FIG. 1B, when in the closed configuration, loops  12  and  22  are adjacent to each other, crossbars  16  and  26  are adjacent to each other, and cutting element  20  is positioned snugly within aperture  18 . The crossbar  16  thus acts as a counter element for cutting element  20 . 
     With reference to FIGS. 2A and 2B, there is shown a surgical clip, referenced generally  110 , according to a second embodiment of the present invention, the clip being in an open configuration and in a closed configuration, respectively. Clip  110  is similar to clip  10  (FIGS. 1A,  1 B) in that it defines a coil of two complete circles, including an intermediate portion  113  formed of a shape memory alloy, but clip  110  is provided with a crossbar  116  and bar  126  on respective loops  112 ,  122 . Crossbar  116  and bar  126  may be fastened to respective loops  12  and  22  by any suitable means. Bar  126  is also provided with a surgical blade  128  which extends out of bar  126  such that, when the clip  110  is in the closed configuration, blade  128  presses against crossbar  116 . Thus, crossbar  116  acts as a counter element for blade  128 . 
     FIGS. 3A-D illustrate a surgical clip, referenced generally  130 , according to a third embodiment of the present invention. Clip  130  includes an intermediate portion  13  formed of a shape memory alloy and defines a coil of two complete circles, as does clip  10 , and has similar loops  12  and  22 . However, in this embodiment of the present invention, loop  22  of clip  130  is provided with a cutting element  133  in the form of an L-shaped arm  132  having a blade  134  at its end which extends towards the center of loop  22 . Loop  12  is provided with a counter element  136  in the form of an arm  137  having a U-shaped portion  138  at its end, the open end of the U facing towards the center of loop  12 . L-shaped element  132  and counter element  136  may be fastened to respective loops  22  and  12  by any suitable means. It will be appreciated by persons skilled in the art that cutting element  133  and arm  132  may be configured as having any other suitable shapes whereby they will function as a cutting element and counter element for the purposes of the present invention. 
     FIGS. 3A-B shows clip  130  with intermediate portion  13  in a plastic state, wherein the loops  12  and  22  have been moved apart. When intermediate portion  13  is in an elastic state, as shown in FIGS. 3C-D, loops  12  and  22  are pressed against each other. As shown in FIG. 3C, blade  134  of cutting element  133  is positioned adjacent yet apart from U-shaped portion  138  of counter element  136 . By manually applying external pressure to both cutting element  133  and counter element  136 , in the direction of arrows A and B, respectively, these elements are forced together such that they make contact, as shown in FIG. 3D, blade  134  being pressed against counter element  136  at approximately the center of the U-shaped portion  138  thereof. After release of cutting element  133  and counter element  136 , these elements are allowed to return to their positions shown in FIG.  3 C. 
     FIGS. 4A,  4 B,  4 C, and  4 D illustrate a surgical clip, referenced generally  140 , according at to a fourth embodiment of the present invention. Clip  140  includes two ring portions  142 ,  144 , which are attached at an intermediate portion  150 . While, if desired, the entire clip  140  may be formed of a shape memory alloy, it is essential that at least the intermediate portion  150  be formed of a shape memory alloy. Ring portions  142  and  144  are provided with respective crossbars  146  and  148 . At the center of crossbar  146  there is provided a cutting element  152  which is slidably attached therethrough. Cutting element  152  includes a ring-shaped head portion  156  and a cylindrical portion  158  having an aperture  159 . Crossbar  148  is provided with a counter element  162  in the form of a cylindrical aperture  154 , of size and configuration similar to that of cylindrical portion  158  of cutting element  152 , and of a flange portion  160  (FIGS. 4B,  4 C,  4 D), positioned about aperture  154  on the side of crossbar  148  which is distal to crossbar  146 . 
     While the cutting element  152  and counter element  162  of clip  140  are shown as having a particular size and shape, it will be appreciated by persons skilled in the art that any suitable configuration of cutting element and counter element may be employed, whereby tissue located therebetween may be sliced or cut out. 
     In FIGS. 4A-B, intermediate portion  150  of clip  140  is shown in its plastic state, wherein ring portions  142  and  144  have been moved apart. When intermediate portion  150  of the clip  140  is in an elastic state, as shown in FIGS. 4C-D, ring portions  142  and  144  are firmly pressed against each other, and cylindrical portion  158  of cutting element  152  is positioned adjacent aperture  154  of counter element  162 . By applying pressure to head portion  156  of cutting element  152  on crossbar  146 , in the direction of arrow B, and to flange portion  160  on counter element  162 , in the direction of arrow C, cylindrical portion  158  is forced into aperture  154 , where it is held in position by the snug fit between cylindrical portion  158  and the inner surface of aperture  154 . 
     It may be noted that, as opposed to the clip  130  (FIGS.  3 A-D), wherein both cutting element  133  and counter element  136  are movable relative to their respective rings  22  and  12 , in the clip  140  only cutting element  152  is movable relative to ring portion  142 , while counter element  162  does not move relative to ring portion  144 . 
     FIG. 4E illustrates a surgical clip according to a fifth embodiment of the present invention. Clip  170  is similar to clip  140  (FIGS. 4A,  4 B,  4 C,  4 D) in that it includes an intermediate portion  150  formed of a shape memory alloy and is provided with ring portions  142  and  144 . However, ring portions  142  and  144  are provided with respective arms  172 ,  174  which extend from corresponding points along ring portions  142 ,  144  into the interior thereof. Arms  172 ,  174  may be fastened to respective ring portions  142 ,  144  by any suitable means. On the end of arm  172  there is formed a cutting element  176  having a head portion  178  and a cylindrical portion  180  having an aperture  181 . The end of arm  174  is provided with a counter element  186  having a cylindrical portion  182  and a cylindrical aperture  184  of size and configuration similar to that of cylindrical portion  180  of cutting element  176 . 
     In FIG. 4E, intermediate portion  150  of clip  170  is shown in a plastic state, wherein the ring portions  142  and  144  have been moved apart. When, however, intermediate portion  150  of clip  170  is in an elastic state (not shown), ring portions  142  and  144  are firmly pressed against each other, and cylindrical portion  178  of cutting element  176  is positioned adjacent aperture  184  of counter element  186 . By applying pressure to head portion  178  of cutting element  176  on arm  172  and to cylindrical portion  182  of counter element  186 , cylindrical portion  180  of cutting element  176  is forced into aperture  184 , where it is held in position by the snug fit between cylindrical portion  180  and the inner surface of aperture  184 . FIGS. 5A and 5B are pictorial illustrations of a counter element, referenced generally  200 , and of a cutting element, referenced generally  210 , which may be employed in the surgical clip  170  shown in 
     FIG.  4 E. Counter element  200  is provided with an X-shaped aperture  202  which corresponds in configuration and size to blade  212  of cutting element  210 . Thus, when employing counter element  200  and cutting element  210  in the device of the present invention, when the intermediate portion of the clip is in an elastic state, as discussed above, counter element  200  and cutting element  210  may be pressed together, thus forcing blade  212  into aperture  202 . 
     A further embodiment of the present invention is illustrated in FIG. 5C, which shows a cutting element  220  and a corresponding counter element  230  which may be employed in the surgical clip according to either of FIGS. 1A and 1B. Cutting element  220  is provided with an elliptically shaped base portion  222  having a pair of needle-like blades  224  protruding therefrom. Counter element  230  is provided with an elliptically shaped base portion  232 , similar in configuration and size to base portion  222  of cutting element  220 , and a flange  234  extending therefrom. Base portion  232  also has an elliptical aperture  236 , whose width is similar to that of blades  224  and whose length is at least equal to the distance between the outer edge of one blade to the outer edge of the other blade. Thus, when employing counter element  230  and cutting element  220  in the device of the present invention, when the intermediate portion of the clip is in an elastic state, as discussed above, counter element  230  and cutting element  220  are pressed together, thus forcing blades  224  into aperture  236 . 
     FIGS. 5D,  5 E,  5 F,  5 G,  5 H, and  5 I illustrate several particular examples of the relationship between specific blade element and counter element combinations, which may replace the blade elements and counter element employed in the embodiments of the present invention shown in FIGS. 2-4. As shown in FIG. 5D, when the shape memory alloy of the device is in an elastic state, loops  12  and  22  are pressed against each other. FIGS. 5D and 5E show blade  240  when it has made contact with each of the flat-surfaced counter elements  242  and  244 . In FIG. 5F there are shown a blade  240  and a counter element  248  having a recess  250  shaped to accommodate the tip of blade  240 . FIG. 5G shows a blade  246  and a counter element  252  having a cylindrical recess  254  extending therethrough. Recess  254  is large enough to receive the tip  256  of blade  246 . However, if blade  246  is moved further into recess  254 , its movement will be stopped when it has reached the point at which the width of blade  246  which has entered recess  254  is equal to the width of recess  254 . In FIG. 5H, there is provided a counter element  258  having a triangular recess  260  shaped to accommodate the tip of blade  246 . FIG. 5I shows an alternative embodiment, wherein the blade element and counter element combination has been replaced by a pair of blade elements  268  in the form of blades  262  which come into contact, when loops  12  and  22  (FIG. 5D) are pressed against each other, such that the tip  264  of each blade  262  lies along a side  266  of the other blade  262 . 
     FIGS. 6A-D show a surgical clip  300  according to a sixth embodiment of the present invention. Clip  300  includes two ring portions  302 ,  304 , which are attached at an intermediate portion  306  formed of a shape memory alloy. Ring portion  302  is provided with an off-center crossbar  308  having a rotatable blade element  310  thereon. Cutting element  310  includes a blade  312  and a head portion  314  by means of which the blade  312  may be rotated downward toward the center of ring portion  302 . Across the center of ring  304  there is provided a counter element  316  configured as a pair of parallel bars  318  having a generally rectangular gap  320  therebetween. Bars  318  are positioned such that gap  320  is wide enough to accommodate blade  312 , yet narrow enough to provide a snug fit therefor. It will be appreciated by persons skilled in the art that counter element  316  may be replaced by any other counter element suitable for use with cutting blade  312 . 
     When intermediate portion  306  is in a plastic state, ring portions  203  and  304  may be moved apart, as to the position shown in FIG.  6 A. When, however, as shown in FIGS. 6B-D, intermediate portion  306  of the clip  300  is in an elastic state, ring portions  302  and  304  are firmly pressed against each other. As shown in FIG. 6B, by applying pressure in the general direction of arrow D to head portion  314  of cutting element  310 , blade  312  is rotated about crossbar  308 , such that it moves downward, in the sense of FIG.  6 B. This will result in the cutting element  310  being in the position shown in FIG. 6C, wherein blade  312  is snugly fit within gap  320  of counter element  316 . If desired, the cutting element  310  may be provided with biasing or similar means (not shown), whereby the blade  312  is pulled or pushed out of gap  320  so that it is automatically returned to its upper position, as shown in FIG.  6 D. 
     With reference to FIGS. 7A-D, there are shown portions  52  and  54  of a hollow organ  50 , which it is desired to join together by anastomosis. Hollow organ  50  may be a colon, or any other hollow organ which requires anastomosis. Alternatively, the method of the present invention may be employed for the connection of a portion of a first hollow organ to a second hollow organ, such as the connection of a colon portion to a stomach. The method of the present invention will now be described with reference to clip  10 . However, it will be appreciated by persons skilled in the art that the method of the present invention may be carried out by utilizing any embodiment of the clip, or by employing any of the elements described above, in accordance with the present invention. 
     Additionally, it will be appreciated by persons skilled in the art that a device employing a shape memory alloy, such as a clip according to the present invention, may be described as being of one of two different types. A first type of device employs a shape memory alloy which is in an easily deformable, martensitic state when it is cooled to below room temperature, which achieves a fully or partial austenitic state at room temperature, and which is in a completely austenitic state when heated to at least its upper phase transition temperature, which is somewhere between room temperature and body temperature. According to the second type of device, the shape memory alloy is in an easily deformable, martensitic state at room temperature, whereat the device is deformed and applied, and the shape memory alloy achieves a completely austenitic state when heated to above room temperature. The difference between the two types of devices is in the temperature range at which the shape memory alloy is easily deformable. Thus, by utilizing a device including a shape memory alloy of the second type, allows more freedom in application. The method of the present invention discussed hereinbelow will be described with regard to a device of the first type. 
     Referring again to FIGS. 7A-D, at least the shape memory alloy portion  13  of clip  10  is cooled to at least its lower phase transition temperature, whereat the shape memory alloy is in its martensitic state, as known in the art, the intermediate portion  13  of clip  10  thus being in a plastic state. The lower phase transition temperature may be generally any temperature above −273° C., although more generally it is approximately 25-35° C. below body temperature, preferably approximately 0° C. Loops  12  and  22  are manually moved apart a desired distance and clip  10  is preserved in the cooled state for as long as required until insertion into the organ  50 . 
     Open ends  56  and  58  of separate organ portions  52  and  54  are surgically stapled or sewn closed, as by sutures  72 , thereby resulting in separate closed ends  56   a  and  58   a.  Portions  52  and  54  of organ  50  are drawn together in an adjacent, side-by-side relationship, and adjacent walls  60  and  62  are perforated at punctures  64  and  66 , respectively, the punctures  64  and  66  being adjacent. The size and shape of punctures  64  and  66  are chosen as desired, so as to be able to facilitate positioning of loops  12  and  22  inside respective organ portion  52  and  54 . Clip  10  is introduced into organ portions  52  and  54  by inserting loops  12  and  22  via punctures  64  and  66 , respectively, such that loops  12  and  22  are situated inside organ portions  52  and  54 , so as to straddle respective walls  60  and  62 . While the method of the present invention is described herein in relation to FIGS. 7A-D, wherein both organ portions  52  and  54  are first surgically stapled or sewn closed, it will be understood by persons skilled in the art that either one or both of the organ portions  52  and  54  may be sewn closed after insertion of the surgical clip, without departing from the scope of the invention. 
     The relative positions of portions  52  and  54  of organ  50  and the relative position of clip  10  in relation thereto must be maintained for a period of time during which the temperature of organ  50  is effective to cause the temperature of the intermediate portion  13  of the clip  10  to rise to a temperature at least equal to its upper phase transition temperature, whereat the clip  10  achieves its austenitic state, which is, preferably, below body temperature. During the time that the temperature of the intermediate portion  13  of the clip  10  rises towards its transition temperature, loops  12  and  22  continue to converge and to press the tissue portions  68  and  70  of organ walls  60  and  62  located therebetween more and more tightly against each other. Tissue portions  68  and  70  are defined by the portions of respective walls  60  and  62  located between loops  12  and  22 . Thus, each of tissue portions  68  and  70  is configured as an area similar in shape and size to the loops  12  and  22  of clip  10 . 
     The rate by which the temperature of intermediate portion  13  of clip  10  rises may be accelerated by heating clip  10 , for example, by any method known in the art. 
     Once the temperature of the intermediate portion  13  of clip  10  has risen above its transition temperature, clip  10  has returned to its elastic phase, as shown in FIGS. 7C and 7D, wherein loops  12  and  22  are pressing against each other, and thus maintains walls  60  and  62  in fixed position relative to each other. At the same time, blade  48  of cutting element  20  is being pressed into aperture  18 , thus slicing out a portion of tissue portions  68  and  70  which is similar in size and shape to that of blade  48 . This slicing out of a portion of the tissue will create initial patency of the gastrointestinal tract. 
     It will be appreciated by persons skilled in the art that, if another embodiment of the present invention were employed, such as clip  130  of FIGS. 3A-D, wherein the cutting element  33  and counter-element  136  are actuatable by external manual pressure, such pressure may be provided by any means known in the art, such as by use of an instrument (not shown) designed for this purpose. 
     After a portion of the tissue has been sliced out of tissue portions  68  and  70 , the only pathway from portion  52  to portion  54  of organ  50  is via aperture  18  on crossbar  16  and aperture  28  of cutting element  20 . 
     Due to the pressure exerted by clip  10  on walls  60  and  62  of organ  50 , respective tissue portions  68  and  70  are pressed so tightly against each other that blood flow to these tissue portions ceases, resulting in eventual necrosis of these tissue portions  68  and  70 . As tissue  68  and  70  die, the tissue portions  68   a  and  70   a  immediately thereoutside mend together such that portions  52  and  54  of organ  50  are joined, and organ  50  may function as one continuous organ. Once tissue portions  68  and  70  die, they, together with clip  10 , become separated from walls  62  and  60 , resulting in a hole  74  (FIG.  7 C). Dead tissue portions  70  and  68 , together with clip  10  are passed out of organ  50 , via hole  74 , by the normal activity of the organ. For example, if organ  50  is the small intestine, and the direction of peristalsis is from portion  52  towards portion  54 , then clip  10  and tissue portions  70  and  68  will be passed through portion  54  by the normal activity of the small intestine. 
     It will be appreciated by persons skilled in the art that, if desired, instead of employing clip  10  in the surgical procedure as discussed above, and as illustrated in FIGS. 7A-D, either of clips  140  and  170  may be employed. The use of either of these embodiments of the present invention would require that, after a clip ( 140 ,  170 ) has been introduced into the organ  50  and the intermediate portion thereof has attained its elastic (martensitic) state, as discussed above, the respective cutting element ( 152 ,  176 ) and counter element ( 162 ,  186 ) would have to be manually forced into cutting engagement. This would cause the cutting element ( 152 ,  176 ), together with the counter element ( 162 ,  186 ), to slice out a portion of the tissues located therebetween, the size and shape of the tissue sliced out being similar in size and shape to that of the cylindrical portion ( 158 ,  180 ). This slicing out of a portion of the tissue will create initial patency of the gastrointestinal tract. 
     Alternatively, if desired, any of clips  110 ,  130 , and  300  may be employed in the surgical procedure discussed above. The use of clip  110  would enable the blade  128  and crossbar  116  to automatically make an incision through the portions of the tissue located therebetween, as the blade  128  is forced into cutting engagement with the crossbar  116  when the clip  110  is in an elastic state, as discussed above with regard to FIGS. 2A-B. The use of either of clips  130  and  300  would require that, after the clip ( 130 ,  300 ) has been introduced into the organ  50  and has attained its elastic state, as discussed above, the respective cutting element ( 133 ,  310 ) and counter element ( 136 ,  316 ) would have to be manually forced into cutting engagement. This would cause the cutting element ( 133 ,  310 ), together with the counter element ( 136 ,  316 ), to make an incision through the portions of the tissue located therebetween. This incision through a portion of the tissue will create initial patency of the gastrointestinal tract. If desired, after an incision has been made by any of the clips ( 110 ,  130 ,  300 ), the incision may be widened somewhat, although should not be widened to the entire area of the tissue portions  68  and  70 . 
     It will be appreciated by persons skilled in the art that there is a direct relationship between the size and shape of the clip used in the surgical procedure described above and the size and shape of the resulting hole in the organ. It is thus possible to chose to perform the procedure with a clip of a particular size and shape so as to achieve a hole of a desired size and shape. 
     It will be appreciated by persons skilled in the art that the present invention is not limited by what has been shown and described hereinabove, merely by way of illustrative example. Rather, the scope of the present invention is limited solely by the claims, which follow: