Abstract:
An instrument kit serves for knotless fitting of a tissue to a bone. A pin-shaped anchor element has a suture connected to it. The suture has a loop portion formed into an annular body. An internal diameter of said annular body is chosen in that the pin-shaped anchor element can be moved along its longitudinal axis through said annular body. A length of a section of the suture between the anchor element and the annular body is chosen in that after said anchor element has moved through said annular body, a resulting new loop lies circumferentially and tightly around a strand-shaped tissue section to be fixed at said bone.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to an instrument kit for knotless fixing of tissue to a bone, with a pin-shaped anchor element, which has a longitudinal axis and which is connected to a suture having a loop portion at the end thereof. 
         [0002]    With instrument kits or anchor systems of this kind, a tissue that has become detached from a bone can be fixed to the latter again. 
         [0003]    This need arises in injuries to the shoulder, the hip or the like. There, cuff-like or collar-like tissue regions are present around the joints and are fused to the bone. When injuries occur, principally sports injuries, strand-shaped portions of the tissue are usually detached from the bone on one side. 
         [0004]    A typical injury to the shoulder joint occurs, for example, in handball players who are tackled when throwing a shot for goal. 
         [0005]    The basic principle of fixing involves providing an anchor which is connected to a suture. The suture serves to connect the anchor to the detached tendon endpiece. 
         [0006]    The anchor element itself is introduced into the bone, either being fitted into a previously drilled bore or being driven with impact directly into the bone. In this way, the detached tendon, which is connected to the anchor via the suture, is fixed to the bone again. 
         [0007]    In the early days of this technique, the anchor, with loose suture ends protruding from it, was driven into the bone, and the suture ends were connected to the detached tissue section and then knotted. 
         [0008]    It was found that these knots form undesired elevations under the skin and disrupt the subsequent healing process. 
         [0009]    Therefore, this technique was refined in the sense that so-called knotless anchor systems were developed. In these, a suture in the form of a loop protrudes from the anchor, and the loop is connected to the tendon section that is to be fixed. 
         [0010]    The torn-off tissue is therefore tensioned, or fixed as tightly as possible on the bone, not by means of a suture being suitably tensioned and then knotted, but instead by virtue of the fact that the loop can be tensioned by suitable configuration of the anchor element. 
         [0011]    Devices of this kind or instrument kits of this kind are known from DE 10 2006 010 116 A, EP 1 199 036 B1 or WO 2005/102190 A2, for example. 
       SUMMARY OF THE INVENTION 
       [0012]    It is an object of the invention to refine an instrument kit of this kind for knotless fixing in such a way that the fixing procedure can be performed safely, easily and in a targeted manner. 
         [0013]    This object is achieved by an instrument kit for knotless fixing comprising a pin-shaped anchor element which can be anchored in a bone, said pin-shaped anchor element has a longitudinal axis extending along said pin-shaped anchor element and an outer diameter; a suture connected to said pin-shaped anchor element, said suture having a loop portion, said loop portion being formed into an annular body, said annular body having an internal diameter being chosen in that said pin-shaped anchor element can be moved along its longitudinal axis through said annular body; a length of a section of said suture between said anchor element and said annular body is chosen in that, after said anchor element has moved through said annular body, a resulting new loop lies circumferentially and tightly around a strand-shaped tissue section to be fixed at said bone. 
         [0014]    These measures have numerous advantages. 
         [0015]    The basic structure is such that the anchor element is connected, via a portion of the suture having a defined length, to the loop portion which is formed into an annular body. By choosing the internal diameter of the annular body in such a way that the anchor element can be pushed through this annular body, a new loop is created after the anchor element has been pushed through. 
         [0016]    This now newly formed loop can be used to be placed around a strandshaped tissue section. By pulling on the anchor element already moved through the annular body, this loop becomes ever tighter, i.e. arranges itself ever tighter around the strand-shaped tissue section that is to be fixed. This is controlled in practice by the depth to which the anchor element is driven into the bone. Since the operating surgeon knows approximately how thick this strand-shaped tissue section is, he also knows what length to choose for the portion of the suture between the annular body and the anchor element in order to form a loop that tightly encloses the strand-shaped tissue section and accordingly draws the latter with tensioning to the annular body or in the direction of the anchor element. 
         [0017]    It is possible for this length to be individually adjusted in situ or to be set already at the place of manufacture on the basis of experience. It is known that, for example, the height of a cuff surrounding a human shoulder has a certain measurement, i.e. it is also then known what diameter a strand of tissue has that is partially torn off from this cuff. 
         [0018]    During handling, the assembly composed of the anchor element, of the suture portion protruding therefrom and of the annular body, is placed laterally around the strand-shaped tissue section. The annular body can already be placed on the bone surface at the site where the anchor element is intended to be driven in. Thereafter, the anchor element is placed centrally in the annular body, as a result of which the portion of the suture between anchor element and annular body has already arranged itself around the strand-shaped tissue section. By driving the anchor element through the annular body and into the bone, this new loop is then drawn tight around the strand-shaped tissue section and draws the latter onto the bone. The depth to which the anchor element is driven into the bone thus determines the degree of tensioning of the new loop for fixing the strand-shaped tissue section. 
         [0019]    The operating surgeon does not have to perform any complicated assembly steps, as is the case, for example, in anchor pieces composed of multi-part elements. The fixing procedure is easy to carry out, i.e. the assembly composed of anchor element, suture and annular body simply has to be placed around the strand-shaped tissue section, and the anchor element then driven through the annular body into the bone. 
         [0020]    The annular body, formed from the suture itself, can, with suitable material of the suture, be preformed as an annular body if the suture material has a correspondingly sufficient dimensional stability. This annular body can also be configured by the fact that the portion between the anchor element and the annular body to be configured is formed by two suture portions of a single suture, which as a whole is configured as a loop. If, as has been mentioned, the material allows the annular body to be configured with suitable dimensional stability, the length portion of the suture between the annular body and the anchor element is then configured as a double strand. Suitable auxiliary measures can also be taken to maintain the annular body as such; for example, at the site of the annular body from which this double strand leads away, a small clip or a fastening point is formed, for example by a spot of adhesive or the like. 
         [0021]    Bearing in mind that, after the anchor element has been forced through the annular body, the latter opens and this suture portion forms part of the loop which as a whole is placed around the strand-shaped tissue section, this length portion accordingly has to be added on, since otherwise the anchor element would have to be driven unnecessarily deeply into the bone. 
         [0022]    It is important that this annular body is present at the outset in order to provide the operator with a clear orientation as to where the anchor element should be guided through. In the case where the ring geometry is thereafter lost, the half length of the circumference of this annular body must then be added to the length of the portion of the suture between the original annular body and the anchor element, in order finally to obtain a loop length that is exactly sufficient to be placed circumferentially and tightly around the strand-shaped tissue section and to build up the sufficient tension by suitable driving-in of the anchor element in the bone. The length of the suture, i.e. the length of the suture portion plus the half circumference of the annular body, is to be chosen such that the tissue section is securely enclosed. 
         [0023]    In another embodiment of the invention, the loop portion is guided around a ring element. 
         [0024]    This measure has the advantage that the loop geometry is determined by this additional ring element, such that, even with suture materials that are very slack, the ring geometry is still maintained. This ring element also remains in the body after the anchor element has been driven through the ring element. 
         [0025]    This ring element is an element that is easy to handle, i.e. the operating surgeon can grip it by hand, for example, after he has placed the assembly around the strand-shaped tissue section, and can place it at a very defined location on the bone, which location is favourable for the driving-in of the anchor piece. 
         [0026]    In another embodiment of the invention, the ring element is designed as a ring on whose circumferential outer face a recess is present, into which the loop portion can be placed. 
         [0027]    This measure has the advantage that the original loop portion can already be placed into the ring element or into the outer recess at the place of manufacture, and the corresponding annular body is then formed from the suture material. 
         [0028]    In another embodiment of the invention, the recess is designed in such a way that the suture portion is secure against slipping off. 
         [0029]    This measure has the advantage that the suture, for example at the place of manufacture, is pressed with a certain pressure into the recess, such that this assembly is then maintained firmly during handling, and the ring does not come loose from the suture, or vice versa. 
         [0030]    This handling is first of all the packaging procedure after production, the opening of the package at the place where the operation is being performed, the handing to the operating surgeon, and then also the handling by the operating surgeon upon application to the tissue section. In all these manoeuvres, the suture portion remains firmly secured in the ring. 
         [0031]    This considerably facilitates the handling of the device. 
         [0032]    In another embodiment of the invention, the anchor element has a proximal attachment site to which the suture can be attached. 
         [0033]    This measure has the advantage that the length of the suture portion, in particular the length of the portion between the anchor element and the annular body, can be adapted using this attachment site. Thus, with one and the same physical embodiment of anchor element and ring, an assembly can be made available which is suitable, for example, for placing around a relatively thick strand of tissue or which, with a suitably shorter design of this portion between anchor element and annular body, is suitable for placing around a substantially thinner strand. 
         [0034]    This also opens up the possibility that the thickness of the tissue section or strand to be secured can first of all be determined directly in situ, and then the suture can be applied to the proximal attachment site so as to provide optimal conditions. 
         [0035]    Optimal conditions means that the loop formed after the anchor element has been pushed through the ring element bears tightly around the outer face of the tissue to be fixed, such that this tissue is held securely and, at the same time, the tensioning is already built up when the anchor is driven to the full extent into the bone. This means that the proximal end of the anchor comes to lie at the height of the bone surface. This then results in the anchor element being introduced into the bone in a manner that is as atraumatic as possible, and without its having to penetrate unnecessarily deeply into the bone. This leads not only to much less traumatic anchoring, but also to a very high degree of flexibility in respect of the tissue sections that are to be fixed. 
         [0036]    In another embodiment of the invention, the attachment site is a circumferential groove on the outer face of the anchor body, into which groove the anchor-side end of the suture can be placed. 
         [0037]    This measure has the advantage of providing a relatively stable form-fit connection between the suture and the anchor element. 
         [0038]    The end of the suture directed towards the anchor element is wound once round this circumferential groove and then suitably secured. This securing can easily be provided by a knot or some other clamping piece, which can already be made available at the place of manufacture. In the case where a knot is to be made, the anchor element then has a corresponding recess in order to be able to receive this knot, such that the latter does not protrude laterally. However, the principle of the knotless anchor is then still maintained, since this is understood as meaning that no new knot has to be provided during the actual fixing of the tissue. This is the case here, since the fixing is provided by the newly created loop after the anchor element has been driven through the annular body. 
         [0039]    In another embodiment of the invention, the proximal end of the anchor element has an engagement feature for a driving-in tool. 
         [0040]    This measure has the advantage that a further component of the instrument kit, namely a driving-in tool, can be applied to the anchor element in order to drive the latter through the annular body into the bone. 
         [0041]    In another embodiment, the anchor element is designed as a solid cylindrical body, of which the distal end is designed as a conical tip. 
         [0042]    This measure has the advantage, for example, that the anchor element can be driven directly into the bone via the tip, without a bore first having to be prepared. 
         [0043]    This also increases the flexibility, since the operating surgeon, after placing the assembly on the tissue section that is to be fixed, can first of all look for a suitable location on the bone where he places the annular body and then accordingly applies the tip of the anchor element in order to drive the latter in. If a bore had to be prepared beforehand, he would then be restricted to the position and orientation of this bore. This therefore also increases the flexibility of use of such an instrument kit. 
         [0044]    In another embodiment of the invention, the engagement feature is designed as a bore extending through the body of the anchor element in the longitudinal direction. 
         [0045]    This measure, known per se, has the advantage that the engagement between the driving-in tool and the anchor element can take place quite simply via this bore, namely by pushing a corresponding projection of the driving-in tool into this bore. 
         [0046]    In another embodiment of the invention, the bore extends completely through the body, and the conical tip is designed as a truncated cone, and a driving-in tool inserted into the bore has a tip, which supplements the truncated cone so as to form a pointed cone. 
         [0047]    This measure has the advantage that the tip of the driving-in tool protruding past the truncated cone can be suitably stable and solid or made from a metal, so as to be able to drive the assembly easily and in a targeted manner into the bone. 
         [0048]    After the driving-in tool has been removed, the anchor element remains in the body, with only the blunt truncated cone then representing the distal front end of the anchor element. In this way, the anchor element itself can be made from other materials, including materials that are less impact-resistant. This also makes it possible in general to design the anchor element as a relatively small, weak component, such that fixing procedures of this kind can also be performed, for example, on bone areas that do not have such a large surface area as the shoulder. 
         [0049]    In another embodiment of the invention, a holding device is provided, to which a driving-in tool connected to the anchor element is connected, and which at the distal end has a clamp into which the ring element and the suture portion can be laterally clipped. 
         [0050]    This measure has the advantage that the holding device holds the driving-in tool in a defined orientation, in which the anchor element can then be applied to the driving-in tool. By means of the clamp at the distal end, the ring element can at the same time be brought into the correct orientation, such that anchor element and ring element are in an orientation to each other in which the anchor element simply has to be driven through the ring element by means of a linear advance motion. By forming a clamp in which the ring element can be clipped, this assembly is easy to produce and, of course, then also easy to dismantle after the anchor element has already been driven either partially or completely through the ring element. 
         [0051]    In another embodiment of the invention, the holding device has a guide, extending laterally with respect to the longitudinal axis, for the suture portion between annular body and anchor element. 
         [0052]    This measure has the advantage that, by means of this guide, this suture portion between annular body and anchor element lies in a defined orientation, which then makes it easier for the operating surgeon to move this suture portion laterally towards the tissue that is to be fixed and apply it thereto. 
         [0053]    In another embodiment of the invention, the guide is designed as a vertical bracket which bulges out laterally and whose side facing the suture portion has a recess for receiving the suture portion. 
         [0054]    This measure has the advantage that this suture portion can be held and guided in the recess of the outwardly bulging bracket. 
         [0055]    This means, for example, that this complete assembly of the instrument kit can already be produced before the operation. If, before the surgical intervention, it is to be individually adapted to the diameter of the tissue, this can be done by an assistant. The prepared instrument kit is then handed to the operating surgeon, who then guides it laterally onto the tissue strand that is to be fixed, places the clamp with the ring element onto the bone, and then simply has to impact the driving-in tool in order to drive the latter, together with the anchor element to be secured thereon, in a targeted manner through the ring element into the bone. 
         [0056]    In another embodiment of the invention, the driving-in tool is mounted in a vertically adjustable manner on the proximal end of the bracket. 
         [0057]    This measure has the advantage of permitting further individual adaptability. 
         [0058]    In another embodiment of the invention, the clamp, which is arranged at the proximal end of the bracket, and the annular body of the suture portion are held in such an orientation that the annular body can be placed flat on an outer face of the bone. 
         [0059]    This measure has the advantage that the instrument kit can be guided towards, oriented with respect to and placed on the bone surface much more easily by the operating surgeon. 
         [0060]    In another embodiment of the invention, the annular body is held in the clamp in an orientation in which the longitudinal axis of the anchor element is centrally perpendicular with respect to the plane of the ring. 
         [0061]    This geometry allows the operating surgeon to apply the clamp in a targeted manner and also provides him with a visual indication of the impaction direction or drive direction in which the anchor element is to be driven in. If he knows approximately how long this anchor element is, he then knows the orientation in which he has to apply the instrument kit in order in each case to have sufficient bone substance available into which the anchor element can be driven. 
         [0062]    This also considerably increases the flexibility of use of the instrument kit. 
         [0063]    It will be appreciated that the aforementioned features and the features still to be explained below can be used not only in the respectively cited combination but also in other combinations or singly, without departing from the scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0064]    Illustrative embodiments of the invention are explained in more detail in the description below and are depicted in the drawing, in which: 
           [0065]      FIG. 1  shows a perspective view of the assembly composed of an anchor element and of a suture portion protruding laterally in an arc shape therefrom and opening into the annular body, 
           [0066]      FIG. 2  shows a corresponding view where, in order to stabilize the annular body, the latter is placed around a ring element, 
           [0067]      FIG. 3  shows the complete assembly of an instrument kit, an embodiment being depicted here in which the suture is secured on the anchor element in a circumferential groove, is guided as a double strand to the annular body, and this double strand is received in a lateral guide piece of a bracket, and at the same time a driving-in tool is mounted on the anchor element, 
           [0068]      FIG. 4  shows a very schematic side view of the structural elements from  FIG. 1 , this view illustrating how the portion of the suture between anchor element and ring element can be placed around a strand-shaped tissue that is to be fixed, and 
           [0069]      FIG. 5  shows the anchor element with tissue fixed to the bone. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0070]    An instrument kit shown in  FIGS. 1 to 5  is designated overall by reference number  10 . 
         [0071]    An important structural group of the instrument kit  10  is the anchor element  12  shown in  FIGS. 1 and 2  and in the form of a pin  14 . 
         [0072]    The pin  14  has a solid cylindrical body  16 , which merges at the distal end into a narrowing tip  18 . The tip is designed as a truncated cone  20 . 
         [0073]    A continuous bore  22  extends centrally all the way through the anchor element  12  along the longitudinal axis  21  of the latter. This bore  22  can also be provided with an internal thread at the proximal end area. 
         [0074]    On the outer face of the cylindrical body  16 , various indentations  24  are provided, which are intended to act as barbs after the anchor element  12  has been driven into a bone. 
         [0075]    Near its proximal end, the cylindrical body  16  has a circumferential annular groove  26 . In this proximal end area, the cylindrical body  16  has a flattened face  28 . 
         [0076]    The anchor element  12  is connected to a suture  30 . At its end remote from the anchor element  12 , this suture  30  has a loop portion  32 , which is formed into an annular body  33 . 
         [0077]    The internal diameter  34  of the annular body  33  is chosen such that it is slightly greater than the external diameter  36  of the cylindrical body  16 , with the result that the cylindrical body  16 , directed downwards in the view in  FIG. 1 , can be easily moved through the interior of the annular body  33 . 
         [0078]    A laterally outwardly curved portion  38  of the suture extends between the cylindrical body  16  and the annular body  33 . 
         [0079]      FIG. 1  shows that the annular body  33 , as a closed ring, consists of the suture material, which is connected fixedly to the portion  38 . 
         [0080]    At its end remote from the annular body  33 , the portion  38  is secured on the proximal end of the cylindrical body  16 . 
         [0081]    This can be done, for example, by means of this end being inserted into an opening (not shown) in the cylindrical body  16  and secured there, which can be carried out already at the place of manufacture. 
         [0082]    However, it is also possible to secure this end of the suture  30  on the anchor element  12  by placing it in the annular groove  26  and knotting it in the area of the flattened face  28 . In this embodiment, the length of the portion  38  is then correspondingly variable. 
         [0083]    However, it is also possible to design the suture  30  such that, starting from the cylindrical body  16 , it is designed as a double strand, which then divides to form the annular body  33 . However, measures then have to be taken to maintain the annular body  33  as a ring. This can be achieved, for example, by a corresponding plastic deformability of the material of the suture. At the branch site  39 , i.e. at the site where the double strand leaves the annular body, a corresponding clip or a spot of adhesive can be applied in order to maintain the ring geometry of the annular body  33 . In this case, the annular body is then designed as one strand. 
         [0084]      FIG. 2  shows an embodiment in which the annular body  33  is placed around a ring element  42 . 
         [0085]    The ring element  42  consists here of a metallic, stiff and stable ring  44 , on the circumferential outer face of which a recess  46  is provided, for example a groove, into which the annular body  33  can be placed or pressed in with a snug fit from the outside. 
         [0086]    Depending on the requirements at the place of manufacture, the annular body  33  can be designed as a continuous prefabricated ring, or the ring  44  can be designed as a slotted ring, so as to make it easier for the suture to be pushed over or inserted. If the material of the suture  30  has a certain elasticity, this annular body  33  can be simply pushed over a closed ring. The configuration in  FIG. 2  ensures that the annular body  33  maintains its ring geometry even when the suture material is flexurally slack, since this ring geometry is predefined by the ring element  42 . 
         [0087]    It is also possible for the assembly shown in  FIG. 2  to be already prefabricated as such at the place of manufacture. 
         [0088]      FIG. 3  now shows how further structural parts of the instrument kit  10  are designed and handled. 
         [0089]    Here, a driving-in tool  50  can first be seen which, at the proximal end, has a strike head  52 , which merges at the distal end into a slightly thinner bar  54 . 
         [0090]    From the distal end of the bar  54  itself, a rod  56  projects which is provided at its outer end with a tip  58 . 
         [0091]    The external diameter and length of the rod  56  are dimensioned such that it can be pushed through the continuous bore  22  from proximal to distal. If the aforementioned internal thread is present in the bore  22 , a corresponding external thread is present on the outer face of the rod  56 , such that the screw connection provides a firm and secure fit of the anchor element  12  on the driving-in tool  50 . After the driving in, the driving-in tool  50  is unscrewed from the anchor element  12  that has been driven into the bone. The tip  58  protrudes past the truncated cone  20  of the anchor element  12  and is designed such that it supplements the truncated cone  20  so as to form a pointed cone. The material of the rod  56  and of the tip  58  is produced from hard-wearing metallic material, for example medical-grade steel. 
         [0092]    The annular shoulder (not indicated here) in the transition from the bar  54  to the smaller-diameter rod  56  serves as an abutment on the flat proximal end of the cylindrical body  16  of the anchor element  12 . 
         [0093]    The driving-in tool  50  is mounted on a lateral holding device  60  in a vertically adjustable manner, as is indicated by the double arrow  63 . 
         [0094]    For this purpose, the holding device  60  has a rail  62 , on which the strike head  52  is guided in a vertically adjustable manner. 
         [0095]    The rail  62  continues in the form of a laterally outwardly bulging bracket  65 , at the lower end of which a clamp  70  is arranged. The size, the opening and the orientation of the clamp  70  are such that the assembly of ring  44  and annular body  33  of suture material shown in  FIG. 2  can be clipped laterally therein. 
         [0096]      FIG. 3  shows that the portion of the suture  30  between the annular body  33  and the anchor element  12  is designed as a double strand  38 ,  38 ′, which is guided once round the annular groove  26  and knotted on sides of the flattened face. 
         [0097]    Here, the suture  30  is to be designed as an originally single-strand suture of a defined length, and it can then be placed from the outside into the ring element  42 , and the strands  38 ,  38 ′ protruding therefrom are then guided in an inner recess  67  of the bracket  65  to the proximal end of the anchor element  12  and are secured there in the manner previously described. 
         [0098]    In the state shown in  FIG. 3 , the instrument kit  10  is ready for use in a surgical intervention. 
         [0099]    This is shown in a very schematic form in  FIGS. 4 and 5  and, for the sake of clarity, without the actual driving-in tool and the holder. 
         [0100]    By virtue of the vertical adjustability, the driving-in tool  50  and the anchor element  12  mounted thereon can be raised to such an extent that a tendon strand  72  that is to be secured is placed in the curved area or portion  38  of the suture  30 . The instrument kit  10  can then be placed from one side onto the tendon strand  72 , that is to say, in the view in  FIG. 4 , moved from the right to the left. 
         [0101]    The end effect is that the tendon strand  72  is brought into this inner space. In the state of assembly shown in  FIG. 3 , the anchor element  12  can now be driven from above through the ring element  42 . For this purpose, the underside of the ring element  42  is placed onto a bone surface, specifically at a site which is suitable for fixing the tendon strand  72  and also suitable for the driving-in of the anchor element  12 . After it has been driven in, as can be seen in  FIG. 5 , the whole anchor element  12  has penetrated the bone  74 . 
         [0102]    The portion  38  has now fitted around the outer face of the tendon strand  72  and thus forms a loop  40  by which the tendon strand  72  is placed onto the bone  74  and thereby fixed. 
         [0103]    It is clear from  FIG. 5  that the ring element  42  remains on the outer face of the bone  74 . 
         [0104]    The necessary tensioning on the loop  40  can be achieved if the anchor element  12 , from the position shown in  FIG. 5 , is driven slightly farther into the bone  74 . 
         [0105]    It is clear here that the circumferential length of the loop  40  corresponds approximately to the length of the portion  38 , as is shown in  FIG. 4 . It is thus possible to accordingly select the length before the intervention, if the outer circumference of the tendon strand  72  is known. 
         [0106]    If the aforementioned embodiment is used in which the suture is designed as a double strand in the area of the connection between the annular body  33  and the anchor element  12 , and if no such ring element  42  is present, this suture area, i.e. along the length of the circumference of the annular body  33 , can also be used to form the loop  40 , which is then taken into consideration in the corresponding length of the portion  38 . That is to say, if the annular body  33  can be made sufficiently stable, it is possible to use this instrument kit even without the ring element  42 . 
         [0107]    It is also possible for the suture area received in the ring element  42  to be used for securing, by means of this suture area being removed from the ring element  42 . Then, half the length of the circumference of the ring element is to be added for forming the loop  40 .