Abstract:
A surgical clip system which includes a surgical clip having a first clip portion including a first length of material having a closed geometrical shape having a first surface, the shape having a central axis therethrough and having a central opening therein; a pair of support portions associated with the first clip portion; a second clip portion including a second length of material having a closed geometrical shape having a second surface of substantially the same configuration and size as that of the first clip portion, the shape having a central axis therethrough; and a pair of fastening elements formed of a shape memory alloy, each of the fastening elements including a first end and a second end, each of the first ends being attached to the second clip portion; wherein, when at a first temperature or higher, the shape memory alloy is in an elastic state, such that the pair of fastening elements are maintained in a position such that they abut the support portions, and wherein, when at a second temperature or lower, below the first temperature, the shape memory alloy is in a plastic state, thereby enabling the second ends of the pair of fastening elements to be moved away from the second length of material and to be passed between the support portions such that, upon heating of the clip to at least the first temperature, the pair of fastening elements returns to the position such that they abut the support portions, thereby pressing against the pair of support portions, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material.

Description:
FIELD OF THE INVENTION 
     The present invention relates, generally, to the field of surgical clips and, in particular, to the field of surgical clips including a shape memory alloy (SMA). 
     BACKGROUND OF THE INVENTION 
     Several methods are known in the art for joining portions of hollow organs, such as those of 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 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 suture, which reduces elasticity of the junction and adversely affects peristalsis. 
     Junctions using compression devices such as rings and clips ensure high quality 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 shape 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 with increasing pressure and to provide constant pressure at body temperature, due to the inherent properties of the alloys. 
     Advantages of clips made of shape memory alloy materials include simplicity of design, low cost of manufacture, and smallness in size. Also, they possess universal qualities and they ensure their self-evacuation 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 including 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 providing anastomosis to a portion of a digestive tract, including 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 a plurality of clips are required 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 shape memory alloy clip consisting of two parallel coils which is 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 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 this sort of shape 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 in the post-operative period. Furthermore, this additional suturing is problematic in as much as it has to be carried out across a join which includes a portion of the clip, thereby rendering difficult sealing and anastomosis of the organ portions. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide an improved surgical clip system including 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 system which includes a surgical clip having a first clip portion including a first length of material having a closed geometrical shape having a first surface, the shape having a central axis therethrough and having a central opening therein; a pair of support portions associated with the first clip portion; a second clip portion including a second length of material having a closed geometrical shape having a second surface of substantially the same configuration and size as that of the first clip portion, the shape having a central axis therethrough; and a pair of fastening elements formed of a shape memory alloy, each of the fastening elements including a first end and a second end, each of the first ends being attached to the second clip portion; wherein, when at a first temperature or higher, the shape memory alloy is in an elastic state, such that the pair of fastening elements are maintained in a position such that they abut the support portions, and wherein, when at a second temperature or lower, below the first temperature, the shape memory alloy is in a plastic state, thereby enabling the second ends of the pair of fastening elements to be moved away from the second length of material and to be passed between the support portions such that, upon heating of the clip to at least the first temperature, the pair of fastening elements returns to the position such that they abut the support portions, thereby pressing against the pair of support portions, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material. 
     Additionally in accordance with a preferred embodiment of the present invention, the first clip portion, the support portions, and the second clip portion are fabricated from biocompatible material. 
     Further in accordance with a preferred embodiment of the present invention, each of the pair of support portions includes a pair of guide elements between which one of the fastening elements is positioned when in the elastic state and when the first and second lengths of material are pressed towards each other. 
     Yet further in accordance with a preferred embodiment of the present invention, the guide elements are fabricated from biocompatible material. 
     Still further in accordance with a preferred embodiment of the present invention, upon heating of the clip to at least the first temperature, the pair of fastening elements press against the pair of support portions, thereby pressing the first and second lengths of material towards each other such that they are maintained a distance apart of approximately 0.1-1.5 mm. 
     In accordance with another embodiment of the present invention, upon heating of the clip to at least the first temperature, the pair of fastening elements press against the pair of support portions, thereby pressing the first and second lengths of material against each other such that the first and second surfaces substantially abut each other. 
     In accordance with the present invention, the system further includes spacer means for facilitating movement of the second ends of the fastening elements away from the second length of material. The spacer means includes means insertable through the second length of material of the second clip portion. The insertable means includes means for guiding movement of the fastening elements away from the second length of material. The spacer means is fabricated from biocompatible material. 
     In accordance with a second embodiment of the present invention, there is provided a surgical clip system which includes a surgical clip having: a first clip portion including a first length of material having a closed geometrical shape having a first surface, the shape having a central axis therethrough and having a central opening therein; a pair of support portions associated with the first clip portion; a second clip portion including a second length of material having a closed geometrical shape having a second surface of substantially the same configuration and size as that of the first clip portion, the shape having a central axis therethrough; and a pair of fastening elements formed of a superelastic material, each of the fastening elements including a first end and a second end, each of the first ends being attached to the second clip portion; wherein, in the absence of an outside force, the pair of fastening elements are maintained in a position such that they abut the support portions, and wherein, by the application of an outside force, the second ends of the pair of fastening elements are movable away from the second length of material such that they may be passed between the support portions such that, upon removal of the outside force, the pair of fastening elements returns to the position such that they abut the support portions, thereby pressing thereagainst, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material. 
     In accordance with a preferred embodiment of the present invention, there is provided a method for anastomosing an organ of a gastrointestinal tract, the method comprising the following steps: (a) providing a surgical clip system which includes a surgical clip having: a first clip portion including a first length of material having a closed geometrical shape having a first surface, the shape having a central axis therethrough and having a central opening therein; a pair of support portions associated with the first clip portion; a second clip portion including a second length of material having a closed geometrical shape having a second surface of substantially the same configuration and size as that of the first clip portion, the shape having a central axis therethrough; and a pair of fastening elements formed of a shape memory alloy, each of the fastening elements including a first end and a second end, each of the first ends being attached to the second clip portion; wherein, when at a first temperature or higher, the shape memory alloy is in an elastic state, such that the pair of fastening elements are maintained in a position such that they abut the support portions, and wherein, when at a second temperature or lower, below the first temperature, the shape memory alloy is in a plastic state, thereby enabling the second ends of the pair of fastening elements to be moved away from the second length of material and to be passed between the support portions such that, upon heating of the clip to at least the first temperature, the pair of fastening elements returns to the position such that they abut the support portions, thereby pressing thereagainst, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material; (b) cooling at least the fastening elements of the clip to a temperature below its lower phase transition temperature; (c) moving the second ends of the fastening elements away from the second length of material; (d) preparing open ends of first and second organ portions to be joined, such that a cross-sectional area of each organ portion is narrowed relative to the remainder of thereof; (e) inserting the first clip portion into the first organ portion, such that the first length of material abuts the inside surface of the tissue thereof, adjacent the narrowed area thereof; (f) inserting the second clip portion into the second organ portion, such that the second length of material abuts the inside surface of the tissue thereof, adjacent the narrowed area thereof and such that the fastening elements protrude out of the open end of the second organ portion; (g) drawing together the open ends of the first and second organ portions wherein anastomosis is desired such that they face each other, and bringing the open ends closer together such that the fastening elements protruding out of the open end of the second organ portion pass into the open end of the first organ portion, through the first length of material, and through the pair of support portions; (h) maintaining the relative positions of the first and second portions of the gastrointestinal tract and the first and second clip portions in relation thereto, while raising the temperature of at least the fastening elements to a temperature above its upper phase transition temperature, such that the elasticity thereof causes the fastening elements to return to a position such that the fastening elements press against the pair of support portions, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material. 
     Additionally in accordance with the preferred embodiment of the present invention, in the step (h), the temperature of at least the fastening elements is raised to a temperature above its upper phase transition temperature by the artificial application of heat. 
     Further in accordance with the preferred embodiment of the present invention, the surgical clip system further includes spacer means for facilitating movement of the second ends of the fastening elements away from the second length of material; and, between steps (e) and (f), the method includes the additional step (e1) of: inserting the spacer means into the second organ portion. Between steps (f) and (g), the method includes the additional step (f1) of inserting the spacer means through the second length of material of the second clip portion, the fastening elements guided away from the second length of material. The spacer means is fabricated from biocompatible material. 
     In accordance with a second embodiment of the present invention, there is provided a method for anastomosing an organ of a gastrointestinal tract, the method comprising the following steps: (a) providing a surgical clip system which includes a surgical clip having: a first clip portion including a first length of material having a closed geometrical shape having a first surface, the shape having a central axis therethrough and having a central opening therein; a pair of support portions associated with the first clip portion; a second clip portion including a second length of material having a closed geometrical shape having a second surface of substantially the same configuration and size as that of the first clip portion, the shape having a central axis therethrough; and a pair of fastening elements formed of a thermoresilient material, each of the fastening elements including a first end and a second end, each of the first ends being attached to the second clip portion; wherein, in the absence of an outside force, the pair of fastening elements are maintained in a position such that they abut the support portions and wherein, by the application of an outside force, the second ends of the pair of fastening elements are moved away from the second length of material such that they are able to be passed between the support portions such that, upon removal of the outside force, the pair of fastening elements returns to the position such that they abut the support portions, thereby pressing, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material; (b) moving the second ends of the fastening elements away from the second length of material; (c) preparing open ends of first and second organ portions to be joined, such that a cross-sectional area of each organ portion is narrowed relative to the remainder of thereof; (d) inserting the first clip portion into the first organ portion, such that the first length of material abuts the inside surface of the tissue thereof, adjacent the narrowed area thereof; (e) inserting the second clip portion into the second organ portion, such that the second length of material abuts the inside surface of the tissue thereof, adjacent the narrowed area thereof and such that the fastening elements protrude out of the open end of the second organ portion; (f) drawing together the open ends of the first and second organ portions wherein anastomosis is desired such that they face each other, and bringing the open ends closer together such that the fastening elements protruding out of the open end of the second organ portion pass into the open end of the first organ portion, through the first length of material, and through the pair of support portions; (g) maintaining the relative positions of the first and second portions of the gastrointestinal tract and the first and second clip portions in relation thereto, while removing the outside force, thereby allowing the fastening elements to return to a position such that the fastening elements press against the pair of support portions, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be more fully understood and appreciated from the following detailed description, taken in conjunction with the drawings, in which: 
     FIG. 1A is a pictorial illustration of a surgical clip, constructed in accordance with a preferred embodiment of the present invention; 
     FIG. 1B is a side view of the surgical clip of FIG. 1A, taken in the direction of line I—I therein; 
     FIG. 2A is a pictorial illustration of a first element of the surgical clip of FIGS. 1A and 1B; 
     FIG. 2B is a side view of the first element of the surgical clip shown in FIG. 2A, taken along the line II—II therein; 
     FIG. 3A is a pictorial illustration of a second element of the surgical clip of FIGS. 1A and 1B; 
     FIG. 3B is a side view of the second element of the surgical clip shown in FIG. 3A, taken along line III—III therein; 
     FIG. 4 is a pictorial cross-sectional illustration of first and second portions of a hollow organ, inside which there have been placed respective first surgical clip element, shown in FIGS. 2A and 2B, and second surgical clip element, shown in FIGS. 3A and 3B, in accordance with the first embodiment of the present invention, portions of the second element of the surgical clip being in a plastic state; 
     FIG. 5 is a cross-sectional view of the joined hollow organ portions shown in FIG. 4, with the surgical clip elements fastened together. 
     FIG. 6A is a pictorial illustration of a surgical clip, constructed in accordance with a second embodiment of the present invention; 
     FIG. 6B is a side view of the surgical clip of FIG. 6A, taken in the direction of line VI—VI therein; 
     FIG. 7A is a pictorial illustration of a first element of the surgical clip of FIGS. 6A and 6B; 
     FIG. 7B is a side view of the first element of the surgical clip shown in FIG. 7A, taken along the line VIIB—VIIB therein; 
     FIG. 7C is a side view of the first element of the surgical clip shown in FIG. 7B, taken along the line VIIC—VIIC therein; 
     FIG. 8A is a pictorial illustration of a second element of the surgical clip of FIGS. 6A and 6B; 
     FIG. 8B is a side view of the second element of the surgical clip shown in FIG. 8A, taken along line VIII—VIII therein; 
     FIG. 9 is a pictorial cross-sectional illustration of first and second portions of a hollow organ, inside which there have been placed respective first surgical clip element, shown in FIGS. 7A,  7 B, and  7 C, arid second surgical clip element, shown in FIGS. 8A and 8B, in accordance with the second embodiment of the present invention, portions of the second element of the surgical clip being in a plastic state; 
     FIG. 10 is a cross-sectional view of the joined hollow organ portions shown in FIG. 9, with the surgical clip elements fastened together; 
     FIG. 11 is a cross-sectional view of a surgical clip, constructed in accordance with a third embodiment of the present invention; 
     FIG. 12A is a schematic illustration of a surgical clip spacer, constructed in accordance with the present invention; 
     FIG. 12B is a cross-sectional view of the surgical clip spacer of FIG. 12A, taken in the direction of line XIIB—XIIB therein; 
     FIG. 12C is a side view of the surgical clip spacer of FIG. 12A, taken in the direction of line XIIC—XIIC therein; 
     FIG. 13 is a schematic illustration of the surgical clip spacer shown in FIGS. 12A-C, and a second element of a surgical clip, in accordance with the present invention; and 
     FIG. 14 is a schematic illustration of the surgical clip spacer and second element of a surgical clip shown in FIG. 13, in position within a portion of a hollow organ. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention provides a surgical clip system including a surgical clip formed at least partly of a shape memory alloy, such as known in the art, and a method of use thereof, which provides organ tissue compression along the entire periphery of the clip, thereby to ensure satisfactory joining or anastomosis of a punctured organ. 
     Referring now to the drawings, FIGS. 1A and 1B illustrate a surgical clip, referenced generally  10 , according to a preferred embodiment of the present invention. The clip  10  includes a first element  12  and a second element  32  which are to be fastened together, as will be discussed below. The features of first portion  12  are shown more clearly in FIGS. 2A and 2B, and the features of second portion  32  are shown more clearly in FIGS. 3A and 3B. First element  12  and second element  32  may be of any size and shape suitable for use in joining together organ portions, and their specific size and shape are to be determined by the size and shape of the organ portions to be joined. 
     First element  12  comprises a closed ring  14  having an axis of symmetry  20  which passes through end portions  16  of ring  14  and which passes between side portions  18  of ring  14 . A pair of parallel, transverse support bars  22  is attached to side portions  18  of ring portion  14 , the support bars  22  separated by a distance D 1 . Each support bar  22  is preferably provided with a pair of spaced apart guide bars  24  and  26 , disposed on either side of axis  20 , such that guide bars  24  abut axis  20  on opposite sides thereof. While guide bars  24  and  26  are shown (FIGS. 1B and 2B) as being curved, it will be appreciated by persons skilled in the art that guide bars having any other configuration, such as straight bars, may be utilized, without affecting use of the clip  10 . First element  12  may be fabricated from any metal or plastic material which is suitable for use in surgical procedures, such as plastic, stainless steel, or any other biocompatible material. 
     Second portion  32  (FIGS. 1A,  3 A,  3 B) includes a closed ring  34  having an axis of symmetry  30 , which passes through end portions  36  of ring  34  and which passes between side portions  38  of ring  34 . A pair of clamping bars  40  is attached to end portions  36 , on either side of and parallel to axis  30 . Ring  34  may be fabricated from any metal or plastic material which is suitable for use in surgical procedures, such as plastic, stainless steel, or any other biocompatible material, while clamping bars  40  are fabricated from a shape memory alloy or superelastic material, such as is known in the art, which is suitable for use in surgical procedures. If desired, only the actual joint of clamping bars  40  to ring  34  may be formed of a shape memory alloy/superelastic material, while clamping bars  40  may be made from any suitable metal or plastic material. 
     When first element  12  and second element  32  of clip  10  are properly fastened together, clamping bars  40  of second element  32  pass through support bars  22  of first element  12  and press thereagainst, so as to force rings  14  and  34  to abut one another along their entire circumference. The purpose of the guide bars  24  and  26  is to provide a means for the exact positioning of the clamping bars  40  relative to each other. 
     While the surgical clip  10  according to the present invention has been shown and described as one specific embodiment, it will be appreciated by persons skilled in the art that other configurations of the clip may be achieved without departing from the scope of the invention. For example, while rings  14  and  34  are shown in the drawings as being flat and oval and as having circular cross-section, other configurations of rings may be suitable for use in providing surgical clips according to the present invention, such as non-flat or circular clips or clips having non-circular cross-sections. 
     While clamping bars  40  shown in FIGS. 1A and 3A are configured so as to abut each other, it will be appreciated by persons skilled in the art that the amount of spacing between clamping bars  40  is to be determined by the relative distance between the guide bars  24  and  26  provided in first element  12  such that, when first element  12  and second element  32  are fastened together, as will be discussed below, each clamping bar  40  rests in its proper position between a pair of guide bars  24  and  26 . Also, clamping bars  40  may either be configured as straight (not shown), curved as shown in FIG. 3B, or curved as shown in FIGS. 4 and 5. 
     The ring  14 , support bars  22 , guide bars  24  and  26  of first element may be attached by any means known in the art, such as by welding. Similarly, the ring  34  and clamping bars  40  of second element may be attached by any means known in the art, such as by welding. It will be appreciated by persons skilled in the art that the description of the present invention as shown in FIGS. 1-5 relates to a first embodiment of the present invention only, which is fabricated entirely of metal, and wherein the joins between any two portions are metal to metal joins. As will be discussed below with reference to FIGS. 6-10, if desired, the surgical clip of the present invention may be fabricated from both plastic and metal materials. 
     With additional reference to FIG. 4, there are shown portions  44  and  42 , respectively, of a hollow organ  46 , to which it is desired to provide anastomosis, as shown in FIG.  5 . Organ portions  44  and  42  have respective open ends  74  and  72 . 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 in accordance with the present invention. 
     A line of stitches  48 , such as a line of purse string stitches, which are commonly used in surgical procedures, is surgically placed in a tissue section  50  located near the end of organ portion  44 , along the periphery thereof, such that the stitches  48  pass therethrough. The stitches  48  are then gathered, by means known in the art, such that, at the location of the gathered stitches  48 , the diameter d 1  of the cross-sectional area of organ portion  44  is reduced until it is approximately equals the distance D 1  (FIG. 2B) between support bars  22 . First element  12  of clip  10  is then placed, via open end  74 , inside organ portion  44 , such that ring  14  is positioned along the inner surface thereof, and each of guide bars  24  and  26  is inserted between one of stitches  48  and the inner surface of tissue section  50 . Insertion of the guide bars  24  and  26  will cause the tissue portions  54  and  56  to form a fold  52  along stitches  48 , such that tissue portion  54  abuts ring  14  along its entire periphery. Organ portion  44  is then ready to be joined to organ portion  42 . 
     As discussed above, clamping bars  40  of second element  32  of clip  10  may be fabricated either from a thermosensitive shape memory alloy or from a superelastic material. When employing a shape memory alloy, second element  32  is cooled until it reaches its lower phase transition temperature, as known in the art, the clamping bars  40  of second element  32  thus being in a plastic state. The phase transition temperature may be generally any temperature above −273° C., preferably in the range of 25-35° C., and below body temperature. Clamping bars  40  are moved apart a desired distance and second element  32  is preserved in the cooled state for as long as required until insertion into the organ portion  42 . When employing a superelastic material, clamping bars  40  are moved apart a desired distance, by the use of a special instrument intended for this purpose, as discussed below. 
     A line of stitches  58  is surgically placed in a tissue section  60  located near the end of organ portion  42 , along the periphery thereof, such that stitches  58  pass therethrough. The stitches are then gathered, by means known in the art, such that, at the location of the gathered stitches  58 , the diameter d 2  of the cross-sectional area of organ portion  42  is reduced until it is less than the distance D 2  (FIG. 3A) between the side portions  38  of ring  34 . Second element  32  of clip  10  is then placed, via open end  72 , inside organ portion  42  such that ring  34  is positioned along the inner surface thereof, and each of clamping bars  40  is inserted between one of stitches  58  and the inner surface of tissue section  60 , such that clamping bars  40  protrude out of the open end  72  of organ portion  42 . Insertion of the clamping bars  40  will cause the tissue portions  64  and  66  to form a fold  62  along stitches  58 , such that tissue portion  64  abuts ring  34  along its entire periphery. 
     As shown in FIG. 4, organ portions  42  and  44  of organ  46  are positioned adjacent one another, and are brought closer together, such that clamping bars  40  of second element  32  are inserted between support bars  22  of first element  12 . Once they have been brought into contact, as shown in FIG. 5, tissue portion  64  of organ portion  42  abuts tissue portion  54  of organ portion  44 . Clamping bars  40  are then allowed to return to their original position, relative to ring  34 , either by warming of the second element by the organ portion  42 , when a thermosensitive shape memory alloy is utilized, or by removal of the special instrument, when a superelastic material is used, as discussed above. 
     When employing a thermosensitive shape memory alloy, the relative positions of organ portions  42  and  44  of organ  46  and the relative positions of first element  12  and second element  32  in relation thereto must be maintained for a period of time during which the temperature of organ  46  is effective to cause the temperature of the clamping bars  40  to rise to at least its upper phase transition temperature, which, preferably, is body temperature. During the time that the temperature of clamping bars  40  rises towards its transition temperature, rings  14  and  34  converge and press tissue portions  54  and  64  of organ portions  44  and  42  located therebetween more and more tightly against each other. The rate by which the temperature of clamping bars  40  rises may be accelerated by heating clip  10 , for example, by any method known in the art. Once the temperature of clamping bars  40  has risen above the transition temperature, clamping bars  40  have returned to their elastic state, as shown in FIGS. 1A,  1 B,  3 A,  3 B, and  5 , and maintain tissue portions  54  and  64  adjacent one another. 
     Due to the pressure exerted by clip  10  on organ portions  44  and  42 , respective tissue portions  54  and  64  are pressed so tightly against each other that blood flow to these tissue portions ceases, resulting in eventual necrosis of these tissue portions  54  and  64 . As tissue portions  54  and  64  die, the tissue portions  68  and  70  immediately thereoutside mend together such that portions  42  and  44  of organ  46  are joined and organ  46  may function as one continuous organ. Once tissue portions  54  and  64  die, they, together tissue portions  56  and  66  and with clip  10 , become separated from organ portions  42  and  44 , and are passed out of organ  46 , by the normal activity thereof. For example, if organ  46  is the small intestine, and the direction of peristalsis is from portion  42  towards portion  44 , then clip  10  and tissue portions  54 ,  64 ,  56 , and  66  will be passed through portion  44  by the normal activity of the small intestine. 
     Referring now to FIGS. 6A and 6B, there is illustrated a surgical clip, referenced generally  110 , according to a second embodiment of the present invention. It will be clear to those skilled in the art that, as certain portions of surgical clip  110  are similar in configuration and function to corresponding portions of surgical clip  10  (FIGS.  1 - 5 ), their description will not be repeated in the ensuing description of surgical clip  110 . The clip  110  includes a first element  112  and a second element  132  which are to be fastened together, as will be discussed below. The features of first element are shown more clearly in FIGS. 7A,  7 B, and  7 C, and the features of second element  132  are shown more clearly in FIGS. 8A and 8B. 
     First element  112  comprises an elongated disk  114  having first surface  113  and second surface  115 . Disk  114  has an axis of symmetry  120  which passes through end portions  116  of thereof and which passes between side portions  118  thereof. While end portions  116  and side portions  118  provide disk  114  with a closed configuration, the interior of disk  114  is provided with an opening  124 , the function of which will be discussed further below. On either side of axis  120 , within first surface  113 , each of end portions  116  is provided with a rectangular recess. 
     First element  112  is preferably provided with a pair of alignment pins  126 , which extend out of second surface  115 . While, in the embodiment shown, pins  126  are attached to the surface  115  of disk  114  at the portion thereof just below recesses  122 , it will be appreciated by persons skilled in the art that the pins  126  may be attached at any other suitable point of surface  115 . 
     Second element  132  (FIGS. 6B,  8 A,  8 B) includes an elongated disk  134  having first surface  123  and second surface  125 . Disk  134  has an axis of symmetry  130 , which passes through end portions  136  thereof and which passes between side portions  138  thereof. End portions  136  and side portions  138  provide disk  134  with a closed configuration. Disk  134  is provided with an opening  135 . A pair of clamping bars  40  is attached to end portions  136 , on either side of and parallel to axis  130 . Disk  134  may be fabricated from any metal or plastic material which is suitable for use in surgical procedures, such as plastic, stainless steel, or any other biocompatible material, while clamping bars  40  are fabricated from a shape memory alloy or superelastic material, such as is known in the art, which is suitable for use in surgical procedures. If desired, only the actual joint of clamping bars  40  to disk  134  may be formed of a shape memory alloy/superelastic material, while clamping bars  40  may be made from any suitable metal or plastic material. 
     Second element  132  is preferably provided with a pair of bore holes  127 , which extend from surface  125 , at least partially through disk  134 . The exact positioning of holes  127  is determined by the positioning of pins  126  such that, when first element  112  and second element  132  are brought together, as shown in FIGS. 6B and 10, pins  126  will be positioned within respective holes  127 , thus providing clip  110  with means for maintaining alignment between elements  112  and  132 . 
     When first element  112  and second element  132  of clip  110  are properly fastened together, clamping bars  40  of second element  132  pass through opening  124  of first element  112 , sit within respective recesses  122 , and press against surface  113 , so as to force disks  114  and  134  to abut one another along their entire circumference. As noted above, the pins  126  and holes  127  are aligned so as to provide a means for the exact positioning of the clamping bars  40  within recesses  122 . 
     While the surgical clip  110  according to the present invention has been shown and described as one specific embodiment, it will be appreciated by persons skilled in the art that other configurations of the clip may be achieved without departing from the scope of the invention. For example, while disks  114  and  134  are shown in the drawings as being oval and as having a periphery which is thicker in cross-section that its interior, other configurations of disks may be suitable for use in providing surgical clips according to the present invention, such as circular disks or disks having cross-sections of uniform thickness. 
     While clamping bars  40  shown in FIG. 6A and 8A are configured so as to be spaced apart, it will be appreciated by persons skilled in the art that the amount of spacing between clamping bars  40  is to be determined by the relative distance between the recesses  122  provided in first element  112  such that, when first element  112  and second element  132  are fastened together, as will be discussed below, each clamping bar  40  rests in its proper position within its respective recess  122 . Also, clamping bars  40  may either be configured as straight (not shown), curved as shown in FIG. 8B, or curved as shown in FIGS. 9 and 10. 
     The disk  114  of first element  112  and the disk  134  of second element  132  may be fabricated from any suitable biocompatible material, such as plastic, while the alignment pins  126  and clamping bars  40  may be fabricated from metal. In this case, pins  126  may be attached to disk  112  and clamping bars  40  may be attached to disk  134  by any means known in the art, such as by inserting the metal portions into the plastic portions during production. It will be appreciated by persons skilled in the art that the description of the present invention as shown in FIGS. 6-10 relates to a second embodiment of the present invention only, which is fabricated of both plastic and metal. 
     With additional reference to FIG. 9, there are shown portions  44  and  42 , respectively, of a hollow organ  46 , to which it is desired to provide anastomosis, as shown in FIG.  10 . Organ portions  44  and  42  have respective open ends  74  and  72 . The method of the present invention will now be described with reference to clip  110 . 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 in accordance with the present invention. 
     A line of stitches  48 , such as a line of purse string stitches, which are commonly used in surgical procedures, is surgically placed in a tissue section  50  located near the end of organ portion  44 , along the periphery thereof, such that the stitches  48  pass therethrough. The stitches  48  are then gathered, by means known in the art, such that, at the location of the gathered stitches  48 , the diameter d 3  of the cross-sectional area of organ portion  44  is reduced until it is less than the distance D 3  (FIG.  7 C). First element  112  of clip  110  is then placed, via open end  74 , inside organ portion  44 , such that disk  114  is positioned along the inner surface thereof, and each of alignment pins  126  is inserted between one of stitches  48  and the inner surface of tissue section  50 . Insertion of the disk  114 , as far as possible, into organ portion  44  will cause the tissue portions  54  and  56  to form a fold  52  along stitches  48 , such that tissue portion  54  abuts disk  114  along its entire periphery. Organ portion  44  is then ready to be joined to organ portion  42 . 
     As discussed above, clamping bars  40  of second element  132  of clip  110  may be fabricated either from a thermosensitive shape memory alloy or from a superelastic material. When employing a shape memory alloy, second element  132  is cooled until it reaches its lower phase transition temperature, as known in the art, the clamping bars  40  of second element  132  thus being in a plastic state. The phase transition temperature may be generally any temperature above −273° C., preferably in the range of 25-35° C., and below body temperature. Clamping bars  40  are moved apart a desired distance and second element  132  is preserved in the cooled state for as long as required until insertion into the organ portion  42 . When employing a superelastic material, clamping bars  40  are moved apart a desired distance, by the use of a special instrument intended for this purpose, as discussed below. 
     A line of stitches  58  is surgically placed in a tissue section  60  located near the end of organ portion  42 , along the periphery thereof, such that stitches  58  pass therethrough. The stitches are then gathered, by means known in the art, such that, at the location of the gathered stitches  58 , the diameter d 4  of the cross-sectional area of organ portion  42  is reduced until it is less than the distance D 4  (FIG. 8A) between the side portions  138  of disk  134 . Second element  132  of clip  110  is then placed, via open end  72 , inside organ portion  42  such that disk  134  is positioned along the inner surface thereof, and each of clamping bars  40  is inserted between one of stitches  58  and the inner surface of tissue section  60 , such that clamping bars  40  protrude out of the open end  72  of organ portion  42 . Insertion of the clamping bars  40  will cause the tissue portions  64  and  66  to form a fold  62  along stitches  58 , such that tissue portion  64  abuts disk  134  along its entire periphery. 
     As shown in FIG. 9, organ portions  42  and  44  of organ  46  are positioned adjacent one another, and are brought closer together, such that clamping bars  40  of second element  132  are inserted through opening  124  of first element  112 . At the same time, alignment pins  126  are inserted into holes  127 . Once they have been brought into contact, as shown in FIG. 10, tissue portion  64  of organ portion  42  abuts tissue portion  54  of organ portion  44 . Clamping bars  40  are then allowed to return to their original position, relative to disk  134 , either by warming of the second element  132  by the organ portion  42 , when a thermosensitive shape memory alloy is utilized, or by removal of the special instrument, when a superelastic material is used, as discussed above. 
     When employing a thermosensitive shape memory alloy, the relative positions of organ portions  42  and  44  of organ  46  and the relative positions of first element  112  and second element  132  in relation thereto must be maintained for a period of time during which the temperature of organ  46  is effective to cause the temperature of the clamping bars  40  to rise to at least its upper phase transition temperature, which, preferably, is body temperature. During the time that the temperature of clamping bars  40  rises towards its transition temperature, disks  114  and  134  converge and press tissue portions  54  and  64  of organ portions  44  and  42  located therebetween more and more tightly against each other. The rate by which the temperature of clamping bars  40  rises may be accelerated by heating clip  110 , for example, by any method known in the art. Once the temperature of clamping bars  40  has risen above the transition temperature, clamping bars  40  have returned to their elastic state, as shown in FIGS. 6A,  6 B,  8 A,  8 B, and  10 , and maintain tissue portions  54  and  64  adjacent one another. 
     Due to the pressure exerted by clip  110  on organ portions  44  and  42 , respective tissue portions  54  and  64  are pressed so tightly against each other that blood flow to these tissue portions ceases, resulting in eventual necrosis of these tissue portions  54  and  64 . As tissue portions  54  and  64  die, the tissue portions  68  and  70  immediately thereoutside mend together such that portions  42  and  44  of organ  46  are joined and organ  46  may function as one continuous organ. Once tissue portions  54  and  64  die, they, together tissue portions  56  and  66  and with clip  110 , become separated from organ portions  42  and  44 , and are passed out of organ  46 , by the normal activity thereof. For example, if organ  46  is the small intestine, and the direction of peristalsis is from portion  42  towards portion  44 , then clip  110  and tissue portions  54 ,  64 ,  56 , and  66  will be passed through portion  44  by the normal activity of the small intestine. 
     The amount of pressure exerted by the first and second elements of a surgical clip according to the present invention on the tissue portions pressed therebetween is dependent on the relative positions of the elements when they are above their upper phase transition temperature. For example, utilization of a surgical clip, according to either of the first and second embodiments discussed hereinabove, will result in an amount of pressure exerted on the tissue portions sufficient to actually cut through the tissue such that the tissue portions  56  and  66  (FIG. 4) are sliced away from the remainder of relative organ portions  44  and  42 . This is due to the fact that, at temperatures above their upper transition temperature, the first and second elements of each of clips  10  and  110  abut each other. This is clearly shown in FIGS. 1B and 6B, 
     With reference to FIG. 11, there is shown a cross-sectional view of a surgical clip  210 , constructed in accordance with a third embodiment of the present invention. Clip  210  includes a first element  112 , which is identical to first element  112 , shown in FIGS. 7A,  7 B, and  7 C. Clip  210  also includes a second element  132 ′, which is similar in many respects to element  132 , shown in FIGS. 8A and 8B. The difference between clip  210  and clip  110  (FIGS. 6A and 6B) is due to the difference in the relationship between the length of alignment pins  126  and the length of holes  127  (in clip  210 ) or  127 ′ (in clip  210 ). Specifically, with regard to clip  110 , the length L 1  of the pins  126  which protrude past surface  115  (FIG. 7B) is less than or equal to the distance L 2  between surface  125  and the end of hole  127  in second element  132  (FIG.  8 B). Thus, alignment of pins  126  within holes  127  will allow elements  112  and  132  of clip  110  to be brought together until they abut each other. In contrast, with regard to clip  210 , the length L 1  of pins  126  which protrude past surface  115  is greater than the distance L 3  between surface  125  and the end of hole  127 ′ in second element  132 ′ (FIG.  11 ). Thus, alignment of pins  126  within holes  127 ′ will allow elements  112  and  132 ′ of clip  210  to be brought together until pins  126  abut the ends of holes  127 ′. This results in surfaces  115  and  125  of respective elements  112  and  132 ′ being maintained in a spaced relationship, preferably of approximately 0.1-1.5 mm apart. 
     This spaced relationship between elements  112  and  132 ′ of clip  210  enables tissue portions  64  and  54  (FIGS. 5 and 10) to be pressed together without compressing the them to such an extent that they are sliced through, as may occur with clip  110 . In this manner, blood flow to tissue portions  54 ,  64 ,  56 , and  66  is decreased enough such that eventual necrosis of the tissue will occur, preferably within 5 days after the clip has been properly inserted within the organ  46 . As necrosis occurs, tissue portions  68  and  70  will mend together, resulting in joining together of organ portions  42  and  44 , as discussed above. 
     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 organ whose portions are to be joined together. It is thus possible to chose to perform the procedure with a clip of a particular size and shape so as to achieve successful results. 
     In order to facilitate opening of the clamping bars  40  of a second element ( 32 ,  132 ,  132 ′) of a surgical clip ( 10 ,  110 ,  210 ), such as before it is fastened together with a first element ( 12 ,  112 ), as discussed above in accordance with the present invention, the system of the present invention is provided with a surgical clip spacer  80 , shown schematically in FIGS. 12A,  12 B, and  12 C. Spacer  80  includes first and second surfaces  82 ,  84 , between which there is defined a third surface  86 . Surfaces  82  and  84  each include a tapered portion  88  and a wider portion  90 . Tapered portion  88  terminates in a tip  92 . On either side of tip  92 , surface  86  is provided with a groove  94 , which is positioned just next to a center line  96  of surface  86 . 
     With reference to FIG. 13, there is described the proper use of spacer  80 , as it is employed to open the clamping bars  40  of the second element of a surgical clip, for example, second element  32  of clip  10 , discussed above (FIGS.  1 - 5 ). Spacer  80  is positioned such that its tip  92  contacts clamping bars  40  at the point at which they cross each other, and such that clamping bars are aligned with grooves  94 . By holding second element  32  in place and by applying sufficient pressure to spacer  80  in the direction of arrow  100 , clamping bars  40  are caused to separate as they slide along grooves  94 , until the clamping bars  40  reach the position shown in FIG.  4 . 
     With additional reference to FIG. 14, there is discussed the proper use of spacer  80  during the surgical procedure of anastomosis, described above, with reference to FIGS. 4-5. After preparation of organ portion  44 , as shown in FIG. 4, and after stitches  58  have been surgically placed in organ portion  42 , spacer  80  is inserted thereinto, before insertion of second element  32 . Then, second element  32  may be inserted into organ portion  42 , as discussed above with reference to FIG. 4, and spacer  80  may be utilized to separate the clamping bars  40  of second element  32 , as discussed above with reference to FIG.  13 . Once separated, clamping bars  40  of second element  32  may be passed between support bars  22  of first element  12 , as discussed above (FIG.  4 ). By manipulating spacer  80  through organ portion  42 , second element  32  may be released therefrom, thus allowing clamping bars  40  to return to their closed configuration, resulting in first element  12  and second element  32  being fastened together. As discussed above with reference to FIG. 5, once clip  10  becomes separated from organ  46 , the clip  10 , together with spacer  80 , is passed out of organ  46  by the normal activity thereof. 
     While spacer  80  is shown in FIGS. 12-14 as having a particular configuration, it will be appreciated by persons skilled in the art that the configuration shown is for illustrative purposes only. In accordance with the present invention, a spacer having any other suitable shape may be provided. Spacer  80  may be constructed of any material suitable for use in surgical procedures, such as plastic, stainless steel, or any other biocompatible material. 
     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: