Abstract:
A clip for closing blood vessels which branch off from a main blood vessel during an intervention of the main blood vessel has a base body via which the clip can be placed on an inside face of the opened main blood vessel. At least three limbs protrude from the base body and are able to be bent in the direction towards the base body in order to clamp tissue in the area of the branch between the base body and the bent-back limbs thereby closing said branch.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of German Patent Application No. 20 2005 009 061.1 filed on May 31, 2005. 
     FIELD OF THE INVENTION 
     The invention relates to a clip for closing blood vessels, which branch off from a main blood vessel, for example from the aorta, during an intervention on the main blood vessel. 
     The invention relates likewise to a clip applicator for applying a clip of this kind. 
     BACKGROUND OF THE INVENTION 
     Clips are used in the medical sector for clamping blood vessels during surgery. The clips are usually U-shaped or V-shaped and are made from a wire-shaped material. By means of the clip applicator, the clips are applied laterally to the blood vessel that is to be closed, and the two free ends are bent towards one another, as a result of which the vessel lying between them is clamped such that there can be no more flow of blood. 
     In a particular surgical technique for repairing of blood vessels, a stent is inserted into a blood vessel, in most cases a main blood vessel, for example the aorta. To do so, the corresponding section of the aorta has to be clamped off from the blood flow in order to insert the stent. To do this, the aorta is cut open along its length in the clamped-off region. 
     After the stent has been inserted and sutured to the aorta, the clamping on both sides is removed again. 
     When the aorta is clamped off, blood flows back to organs via blood vessels branching off from the main blood vessel, for example via the arteries. Branching-off blood vessels of this kind in most cases have a diameter of 2 to 3 mm, and approximately six to eight such branching-off blood vessels are present in the region of the aorta. 
     Such a return flow has to be prevented, however. To do so, the corresponding organ or vessel has hitherto been closed by hand. 
     It is therefore an object of the invention to provide a clip which, during an surgery on a main blood vessel, permits closure of blood vessels that branch off from this main blood vessel. 
     It is an further object of the invention to provide a clip applicator for applying such a clip. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, the object is achieved by a clip having a base body via which the clip can be placed on an inside face of the opened main blood vessel, and at least three limbs are provided which protrude from the base body and are able to be bent in a direction towards the base body in order to clamp tissue, in the area of the branch, between base body and bent-back limbs, by which means this branch is closed. 
     According to an other aspect of the invention, the object is achieved by a clip applicator having a housing for receiving at least one clip, with an advancer mechanism for pushing a clip forwards, and with a deflector element for bending back the limbs of a clip that has been pushed forwards and has struck the deflector element. 
     By provision of the base body, the clip can be applied to the inside face of the main blood vessel in the area where one or more further blood vessels to be closed branch off. By provision of the several, i.e. at least three, limbs that can be bent back, tissue of the main vessel can be pinched between the base body and the bent-back limbs, and the branch can be closed in this way. The pinched tissue “plugs” the branch opening of the branching-off blood vessel. In this way, the undesired return flow to the organs supplied by these further blood vessels can then be interrupted during the actual operation on the aorta. The branching blood vessels can be closed temporarily or permanently. For removing the clip it is possible to cut it away together with the tissue captured therein or one bend the limbs outwardly for releasing the tissue. 
     In a further embodiment of the invention, four to six limbs are provided. Preferably five protruding limbs are provided. 
     Tests have shown that, with a number of limbs in the range of three to six, all the blood vessels branching off in the area of the clip can be closed in one procedure. 
     In a further embodiment of the invention, the base body has a planar configuration. 
     This measure has the advantage that the base body can be placed in a planar contact onto an area of the inside face of the opened aorta where the blood vessels branch off. That is to say it can be applied with correct positioning, after which the blood vessels branching off in this area are clamped off by means of the several limbs being bent back. The pinched tissue forms a kind of plug by means of which the branch is sealed off. 
     In a further embodiment of the invention, the limbs are designed as planar strips. 
     This measure has the advantage that the pinched tissue will be held gently by the planar strips, and there is no danger of a relatively thin blood vessel of this kind being punctured by a limb. 
     In a further embodiment of the invention, the base body is disc-shaped. 
     This measure has the advantage that a cage or pot-shaped structure is obtained with the clip. The clip can be placed from one side onto the main vessel the limbs facing the branch area. Subsequently the branching-off vessels can be closed by the limbs being bent back. 
     In a further embodiment of the invention, the limbs are bent approximately 90° from the plane of the base body. 
     In its original form, the clip can be produced such that the base body and the limbs initially extend in one plane, for example by punching or by laser-cutting from a planar base body, after which the limbs are bent away from the base body by 90°. 
     In the case of a disc-shaped base body, a corresponding clip can then, for example, be inserted simply into a tubular body or into a tubular magazine of the clip applicator, such that handling is simplified. 
     In a further embodiment of the invention, the clip is produced from metal, in particular from titanium. 
     This measure has the advantage that materials suitable for the medical sector can be chosen which also have the required mechanical stability to exert the clamping forces. 
     In a further embodiment of the invention, the length of the limbs is in the range of between the radius and the diameter of the disc-shaped base body of the clip. 
     This measure has the advantage that the bent-back limbs overlap one another to a greater or lesser extent depending on their length, with the result that the blood vessels are tightly closed by the tissue held between base body and bent-back limbs, and the applied clip sits correspondingly securely in this area. 
     In a further embodiment of the invention, at least the base body of the clip is coated with polytetrafluoroethylene (PTFE). 
     This measure has the advantage that any bleeding that occurs can be rapidly eliminated or can be prevented by means of PTFE assisting in the clotting process. 
     In a further embodiment of the invention, the limbs are pointed at their free ends. 
     This measure has the advantage that the pointed ends penetrate into the tissue (without cutting or damaging it), and, as they are bent further back, they carry these gripped areas of tissue with them and pinch said areas of tissue between base body and bent-back limbs. This can be likened to the closing of a claw-like excavator shovel. 
     The clip applicator according to the invention has a housing for receiving at least one clip, an advancer mechanism for pushing a clip forwards, and a deflector element for bending back the limbs of a clip that has been pushed forwards and has struck the deflector element. By means of this design, the clip can be brought up to the main vessel and the limbs can then be bent back in order to close the vessels, by means of the clip being pushed onto the deflector element by the advancer mechanism. 
     In one embodiment of the clip applicator, the deflector element has oblique deflector surfaces which deflect the limbs of the clip radially inwards. 
     This measure has the advantage that the operating surgeon can first place the clip applicator correctly in position onto the main vessel. In doing so, he can ensure that the laterally branching-off blood vessels are surrounded by the as yet unbent limbs. When the clip is pushed forwards, these clips are then bent back and close these branching-off blood vessels. 
     In a further embodiment of the invention, the deflector surfaces begin at different height levels, so that the several limbs can be bent back beginning one after another. 
     This measure has the advantage that the large number of limbs are bent back in a predetermined sequence, so as to prevent the limbs from becoming entangled with one another as they are bent back. Putting it another way, the limbs are placed over one another, or bent back so as to cross one another, in a very specific pattern. 
     It will be appreciated that the features mentioned above and those still to be explained below can be used not only in the cited combinations, but also in other combinations or singly, without departing from the scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is The invention is described and explained in more detail below on the basis of a selected illustrative embodiment and with reference to the attached drawings, in which: 
         FIG. 1  shows a plan view of a clip after the original production process, in which the base body and five limbs extend in one plane, 
         FIG. 2  shows the clip from  FIG. 1  after the five limbs have been bent 90° from the plane of the base body in one direction, 
         FIG. 3  shows a perspective view of the clip from  FIG. 2 , 
         FIG. 4  shows a highly schematic and partially sectioned side view of a clip being moved towards a deflector element of the clip applicator, 
         FIG. 5  shows a view corresponding to  FIG. 4 , with the limbs just beginning to be bent back, 
         FIG. 6  shows a view comparable to the view in  FIG. 5  after further advance of the clip and, accordingly, after further bending back of the limbs, the latter now extending past the distal end of the clip applicator, 
         FIG. 7  shows a view corresponding to  FIG. 6 , after the clip has been pushed completely through the deflector element, with the limbs now completely bent back, 
         FIG. 8  shows a highly schematic perspective view of a clip applicator according to the invention, 
         FIG. 9  shows a cross section along the line IX-IX in  FIG. 8  in the area of the deflector element, 
         FIG. 10  shows a view comparable to the view in  FIG. 5 , with the clip applicator placed on an inside face of an aorta in the area where an artery branches off, 
         FIG. 11  shows a view corresponding to  FIG. 6 , with the bent-back limbs having already worked themselves into the tissue of the aorta, and 
         FIG. 12  shows a view corresponding to  FIG. 7 , after the clip has been applied by the clip applicator. 
         FIG. 13  shows a plan view of one embodiment of a clip of the present invention after the original production process, in which the base body and three limbs extend in one plane, 
         FIG. 14  shows a plan view of one embodiment of a clip of the present invention wherein a first limb A has been bent-back and a second limb B has been sequentially bent back over first limb A, 
         FIG. 15  shows a plan view of one embodiment of a clip of the present invention wherein a third limb C has been sequentially bent-back over second limb B, to form a cage-shape. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A clip shown in the figures is designated overall by reference number  10 . 
     It will be seen from  FIG. 1  that a clip  10  has a base body  12  in the form of a disc  14  from whose circumferential edge  16  five limbs  18 ,  19 ,  20 ,  21  and  22  extend. 
     In its original form, the clip  10  is manufactured such that the disc  14  and limbs  18 - 22  extend in one plane. This can be done by a punching method or laser-milling or such like. 
     The length of the limbs  18 - 22  corresponds approximately to the diameter of the disc  14 , and their free end is in each case pointed. 
     The clip  10  is preferably made of metal, in particular of titanium. The metal body can then be covered over by coating it with polytetrafluoroethylene (PTFE). 
     It will be seen from  FIGS. 1-3  that each limb  18 - 22  is designed as a planar, strip-shaped and pointed body. The length of the limb  18 - 22  can be in the range of several millimeters to a few centimeters, the thickness being in the range of 0.2 to 0.5 mm. 
     The sequence of views from  FIG. 4  to  FIG. 7  provides a highly schematic representation of how a clip  10  moves through a deflector element  36  at a distal end  31  of a clip applicator  30  shown in  FIGS. 8 and 9  and how the limbs are bent back in this process. 
     The clip applicator  30  for this purpose has a tubular or shaft-shaped housing  32  in which one clip  10  or if appropriate several clips  10  can be fitted. At the proximal end, a grip  34  having a push button  48  is provided via which a clip  10  can be pushed forward, as is described further below. 
     The distal end  31  of the housing  32  is provided with the deflector element  36  which is made up of a ring  37  in which five deflector surfaces  38 ,  39 ,  40 ,  41  and  42  are cut which slope radially inwards in the direction from proximal to distal. For pushing the clip  10  forward, the housing  32  contains a rod-shaped advancer mechanism  45  which, when the button  48  is pressed in, moves from proximal to distal and in so doing moves the clip  10  accommodated inside in the distal direction towards the deflector element  36 . 
       FIG. 4  shows a situation in which the limbs  18  and  20  of the clip  10  are in a position shortly before striking the corresponding deflector surfaces  38  and  40 . In the cross-sectional view, the deflector surface for the limb  19  cannot be seen, and the two other limbs  21  and  22  are concealed by the limbs  18  and  20 . 
       FIG. 5  shows a situation in which the limb  18  has already been bent slightly inwards by the oblique deflector surface  38 . The same applies to the limb  20 . 
     When they have been advanced further, as is shown in  FIG. 6 , the bent-back limbs  18  and  20  protrude past the distal end  31  of the clip applicator  30 , and the five limbs  18 - 22  lie crosswise over one another and form a kind of basket. To ensure that the limbs do not become entangled, the height level of the deflector surfaces  38 - 42  differs such that the limbs are bent back one after the other and in a particular sequence. 
       FIG. 7  shows a situation in which the clip  10  is now completely pushed out from the clip applicator  30 . 
     It will be seen that the limb  19  has first been bent back, after which the limb  18  has been placed over the latter, and the limb  20  has in turn been placed over the limb  18 . The limbs  19  and  21  are then bent back in a corresponding pattern. 
     The sequence of figures from  FIG. 10  to  FIG. 12  shows how a clip  10  according to the invention is applied using a clip applicator  30  according to the invention. To do so, a main blood vessel  50 , for example the aorta, is clamped off at two separate locations and is opened in this area by means of a lengthwise incision. By this means, it is then possible to bring the distal end  31  of the clip applicator  30  to the inside face  54  of the opened aorta  50  from one side, as is shown in  FIG. 10 . This is done in the area of a branch  56  where the other blood vessel  52 , for example an artery, branches off from the main blood vessel  50 . This means that an opening  58  exists in the wall of the main blood vessel  50 , which opening  58  is to be closed. 
     The situation in  FIG. 10  corresponds to the situation in  FIG. 5 . The transition from  FIG. 10  to  FIG. 11  corresponds to the transition from  FIG. 5  to  FIG. 6 . 
     It will be seen from  FIG. 11  that the curved ends of the limbs  18  and  20  advanced past the distal end  31  (the same of course also applying to the other three limbs  19 ,  21  and  22 ) have worked their way into the tissue  62  in the area around the opening  58  and, when further advanced, carry areas of the tissue  62  with them into the space between the base body  12  and the bending-back limbs. In this way, a kind of plug  60  of tissue  62  is formed which, in the same way as before, is connected via a mushroom-shaped neck to the inside face  54  of the main blood vessel  50  and is located in the space inside the bent-back clip  10 . The opening  58 , and consequently the blood vessel  52 , is closed off by this plug  60 . The undesired flow of blood can be ruled out in this way.