Abstract:
The invention relates to improving a surgical system for bonding bodily tissue, comprising a surgical instrument having a bonding device for bonding bodily tissue, said bonding device comprising two tool elements displaceable relative to each other, wherein the instrument comprises a cutting device having a cutting element for cutting through tissue, and the cutting element is displaceably disposed relative to at least one of the tool elements, such that the cutting device is implemented in the form of an HF cutting device, wherein the cutting element comprises a cutting edge defining a cutting plane at an angle relative to a longitudinal axis defined by the instrument in the region of the bonding device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the national phase entry under 35 U.S.C. §371 of International Application No. PCT/EP2010/070017, filed Dec. 17, 2010, and claims the benefit of priority of German Application DE 10 2009 059 195.8, filed Dec. 17, 2009, the contents of both applications being incorporated by reference herein for all purposes. 
     FIELD OF THE INVENTION 
     The present invention pertains to a surgical system for connecting body tissue, comprising a surgical instrument with a connecting means for connecting body tissue, which connecting means comprises two tool elements movable in relation to one another, whereby the instrument comprises a cutting means with a cutting element for cutting tissue and the cutting element is arranged movable in relation to at least one of the tool elements. 
     Furthermore, the present invention pertains to a process for cutting protruding tissue from tubular body tissues connected previously to one another into a single tubular tissue. 
     BACKGROUND 
     Surgical instruments of surgical systems of the type described in the introduction are, for example, known in the form of coagulation instruments, in which protruding, coagulated tissue can be cut with a corresponding, provided cutting means. Furthermore, clip suture devices, with which tubular tissues can be connected to one another in a circular manner, for example, for creating end-to-end anastomoses, and precisely by applying clips, are known. Here, it is usual to equip the clip suture devices with ring knives, i.e., with knives, which have self-contained circular cutting edges. 
     The drawback in all prior-art surgical systems is that partly very high forces are needed for cutting the body tissue. 
     Therefore, the object of the present invention is to perfect a surgical system as well as a process of the type described in the introduction such that body tissue can be cut with lower cutting forces. 
     SUMMARY 
     This object is accomplished according to the present invention with a surgical system of the type described in the introduction in that the cutting element has a cutting edge, which defines a cutting plane sloped in relation to a longitudinal axis defined by the instrument in the area of the connection means. 
     A surface pressure between the cutting element and the tissue can especially be prevented by means of a cutting element with sloped cutting edge in relation to the longitudinal axis of the connection means. Rather, because of the slope, a selective introduction of force at the moment or point in time of the cutting is possible with such a cutting element. Thus, the forces, which are needed for cutting tissue, and especially at the moment of cutting, are markedly lower than in an extensive cutting. An extensive cutting is especially present when the cutting edge defines a cutting plane that runs at right angles to the longitudinal axis of the instrument in the area of the connection means. Due to the sloped cutting edge, the point of intersection may travel along the cutting edge especially also in circular cutting, and starting from a cutting area of the cutting edge, which has the shortest distance of the entire cutting edge from same especially before coming into contact with the tissue to be cut. Designing the cutting element in the manner described has advantages both in a purely mechanical use but also in a monopolar or bipolar embodiment. Especially in the case of a monopolar or bipolar cutting means, the only selective placement of the cutting edge on the tissue to be cut and the thus connected selective current concentration makes possible a problem-free cut and a homogeneous cutting pattern overall. Consequently, the energy needed for performing a cut is markedly reduced both in the mechanical and in the electrical cutting of body tissue. 
     The surgical system can be designed in an especially simple manner, when the cutting means is designed in the form of a mechanical cutting means. For example, the cutting edge can be designed in the form of a sharpened cutting edge. This can, for example, be designed by grinding a suitable, preferably hardened instrument steel. 
     Furthermore, it may be advantageous when the cutting means is designed in the form of an RF cutting means. An RF cutting means makes it possible to cut tissue by means of an RF current. A coagulation of same can be achieved with this especially during the cutting of the tissue, as a result of which undesired bleedings can be prevented. Optionally, the RF cutting means may be provided in combination with a mechanical cutting means as well. 
     An especially simple embodiment of a surgical system may be achieved, especially by providing an RF cutting means, by the cutting means being designed in the form of a monopolar cutting means. 
     An especially clean and defined cut can especially be carried out in a simple manner if the cutting means is designed in the form of a bipolar cutting means. This means that, for example, the cutting element forms an electrode and a corresponding counterelectrode is provided at the instrument, whereby the RF current flows between the electrode and the counterelectrode through the tissues to be connected. 
     Especially for cutting tubular tissues connected to one another, for example, after creating an end-to-end anastomosis, it is advantageous when the cutting edge has a self-contained circular design. Consequently, a, for example, circular or oval cut can be made by a surgeon depending on the need in a simple and reliable manner, and with a mechanical or RF or a combined mechanical/RF cutting means. 
     In order to be able to apply a cutting current, for example, an RF current to the cutting element, in a monopolar or bipolar mode, in a defined manner, it is advantageous when the instrument has at least one cutting terminal that is connected in an electrically conductive manner to the cutting means. 
     The at least one cutting terminal is preferably connected in an electrically conductive manner to the cutting element. It may, especially in a bipolar cutting means, also be connected to a corresponding counterelectrode provided at the instrument. It is especially advantageous when two corresponding cutting terminals are provided. 
     In order to be able to connect tissue to one another in a simple manner with the surgical system, it is advantageous when the tool elements comprise an electrode each, which define a minimal distance from one another, lie opposite one another and point towards one another in a position of proximity of the tool elements. By means of corresponding feed of current to the electrodes, for example, two tissues to be connected to one another can be connected, which can be designated as welding or as sealing, in a simple manner. Here, it is especially desirable when a destruction of the cells involved does not occur. 
     Advantageously, at least one of the electrodes is designed as an RF electrode. This makes it possible to apply an RF current to one or both electrodes, which is especially suitable for connecting tissues, especially body tissues of a patient. 
     According to another preferred embodiment of the present invention, provisions may be made for at least one of the electrodes to be divided into at least two electrode segments, and for the at least two electrode segments to be electrically insulated from each other. The division of at least one of the RF electrodes into two or more electrode segments has especially the advantage that the process parameters for connecting tissues to be connected to one another can be controlled significantly more easily than in non-divided electrodes. The smaller the surfaces, between which the RF current is applied, the more easily the process parameters can be controlled. The temperature, pressure as well as tissue impedance especially have a considerable effect on the connection result. For example, it is thus also possible to adjust the process parameters optimally to the tissue quality and especially also automatically. Moreover, other than when using a clip suture device, no clips that would remain behind as foreign bodies in the body are needed. The electrode segments dividing the RF electrode or RF electrodes especially make a segmented feed of current to the RF electrode possible, such that the tissues to be connected to one another can be welded or sealed to one another in segments. A sequential current feed possible due to segmenting of the RF electrodes makes it possible, during the connection or sealing process, to introduce less energy into the tissues than in comparable, unsegmented RF electrodes. Further, the segmenting has the advantage that between areas connected by RF current feed of the tissues to be connected to one another, tissue areas remain unchanged and essentially undamaged, such that new cell growth starting from same is made possible, which, in addition to the connection brought about by the RF current, makes possible a permanent connection of the tissues by a growing together of same. 
     Furthermore, it may be advantageous when the cutting element is designed as rotatable about the longitudinal axis. Thus, with a predetermined position of the instrument, a position of the cut with the cutting element can be selected in an optional and desired manner. 
     To be able to improve the controllability of the process parameters even further, it is advantageous when each of the RF electrodes is divided into at least two electrode segments, which are electrically insulated from each other. In the sense of this application, at least two electrode segments means two or more electrode segments, i.e., especially three, four, five, six, seven, eight, nine, ten, eleven or twelve. However, more are also conceivable, and depending on the size of the tool elements  20 ,  25 ,  30  or  40  electrode segments as well. 
     Advantageously, at least one of the RF electrodes is divided into a plurality of electrode segments. In the sense of this application, a plurality of electrode segments is defined as two electrode segments, which make possible an even further improved controllability of the process parameters. 
     To be able to feed a current to the electrode segments specifically in a simple and reliable manner, it is advantageous when each electrode segment is connected in an electrically conductive manner to a terminal contact. 
     It is advantageous when the tool elements have a tool element surface each and when at least one tool element surface is flat. This design makes it possible to design the tool elements practically without projections. 
     The tool element surface preferably has a circular design. Thus, circular connections, for example, in end-to-end anastomoses of tubular tissues, can be produced in a simple manner. The interaction with a cutting element, having a self-contained circular cutting edge, is thus especially also simple to embody. 
     It is advantageous if at least one of the electrodes has a self-contained circular design. Of course, all electrodes of the instrument may have a self-contained circular design. Tissue can thus be connected to one another in a simple and reliable manner in a circular pattern, which is advantageous for end-to-end anastomoses, in particular. 
     To be able to grip and optionally to hold tissue between the two tool elements during the connection process, it is advantageous when the tool elements are pivotable and/or displaceable in relation to one another. All in all, a movable arrangement of the tool elements in relation to one another is thus desirable. A pivotability or displaceability of the tool elements in relation to one another may also especially have advantages in the removal of the instrument. For example, a cross section of the instrument in the area of one or both tool elements for removing the instrument can thus be reduced. 
     According to another preferred embodiment, provisions may be made for the instrument to have a shaft, at the distal end of which at least one of the tool elements is arranged or formed. In this way, the instrument may have an especially compact design. Further, the stability of the instrument can be increased overall due to the arrangement or formation of at least one of the tool elements at the distal end of the shaft. Thus, it is especially also possible to design one of the tool elements in a simple manner as fixed in relation to the shaft. 
     It is advantageous when a first tool element comprises an edge surface of the shaft pointing in the distal direction or essentially in the distal direction. For example, a distal end of the shaft can thus be pressed or held against a tissue which will be connected to another tissue in a simple manner. Moreover, a defined tool element surface may thus also be predetermined in a simple and reliable manner. 
     In another preferred embodiment, provisions may also be made for a second tool element to comprise an electrode element that is movable in the shaft direction and movable in the direction of the first tool element and away from same. This embodiment makes it possible, for example, to move the two tool elements in relation to one another such that tissues to be connected to one another can be held in a defined manner between them and can be connected to one another by means of corresponding application of RF current. 
     So that the tool elements can be moved in relation to one another in a simple manner, it is advantageous when the instrument comprises an actuation means for moving the tool elements in relation to one another. 
     It is advantageous when the instrument comprises a cutting actuation means for moving the cutting element and at least one of the tool elements in relation to one another. This enables a surgeon to connect tissues to one another first with the instrument and then to cut the tissues with the cutting means, selectively directly subsequently or even at a later point in time. It is also especially conceivable to couple the cutting actuation means with the actuation means, for example, such that at the end of the connection process, protruding tissues are automatically cut with the cutting means. 
     To further improve the manageability of the surgical instrument, the actuation means and/or cutting actuation means are arranged or formed at a proximal end of the instrument. For example, when the instrument has a shaft, this can be inserted through a body opening into the interior of the patient&#39;s body, whereby the tool elements can then be actuated in relation to one another and/or in relation to the cutting means by means of the actuation means or the cutting actuation means, which preferably still protrude from the body of the patient. Overall, an endoscopic or minimally invasive instrument can thus be designed in a simple manner. 
     The manageability of the instrument can especially be improved for a surgeon in that the actuation means and/or the cutting actuation means comprises two actuation members, which are pivotable in relation to one another, which are in operative connection with at least one of the tool elements or the cutting element for transmitting an actuation force for moving the at least one tool element in relation to the other tool element or the at least one tool element in relation to the cutting element. The actuation members may also basically be designed as only movable in relation to one another, i.e., as an alternative, for example, to a pivotable arrangement they may be arranged displaceable, or pivotable and displaceable, to one another as well 
     To be able to apply an RF current to the RF instrument in a desired manner, the surgical system preferably comprises at least one RF current generator, which can be selectively connected in an electrically conductive manner to the RF electrodes and/or to the cutting element. The optimal current for the connection or cutting of tissue, respectively, can thus especially be adjusted. 
     The object stated in the introduction is further accomplished according to the present invention with a process for cutting protruding tissue from tubular body tissues which were connected previously to one another into a single tubular tissue, in that the two connected body tissues are held and in that the body tissues, starting from a point circulating about a longitudinal axis defined by the single tubular tissue, are cut. 
     Due to the suggested process, markedly lower cutting forces are needed than is the case in knives, whose cutting edges impact simultaneously with all points on the tissue to be separated. Thus, a cleaner cut starting from the point mentioned, which may also be designated as the starting point, can thus be made possible, and both with mechanical and with mono- or bipolar electrical cutting means. 
     In order to be able to remove protruding tissue in end-to-end anastomoses in a defined manner, it is advantageous when a circular cutting element is used. 
     Advantageously, a current is applied to the cutting element for cutting. It may especially be an RF current. Optionally, the tissue may be cut both mechanically and electrosurgically, whereby the electrosurgical procedure has the advantage that possible bleedings occurring during the cutting of the tissue can be stopped by means of instantaneous coagulation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The following description of preferred embodiments of the present invention is used for a detailed explanation in connection with the drawings. In the drawings, 
         FIG. 1  shows a schematic general view of a surgical instrument for connecting body tissues; 
         FIG. 2  shows an enlarged, perspective, partly sectional and open view of area A in  FIG. 1 ; 
         FIG. 3  shows a longitudinal sectional view of the instrument from  FIG. 1  in area A before connecting two tubular tissues; 
         FIG. 4  shows a view similar to  FIG. 3  when welding the tissues for creating an end-to-end anastomosis; 
         FIG. 5  shows a top view of a tool element surface with an RF electrode divided into four electrode segments; 
         FIG. 6  shows a perspective, schematic view of a second exemplary embodiment of a surgical instrument for connecting body tissues; 
         FIG. 7  shows a top view of a schematically shown tool element surface of the instrument from  FIG. 6  in the direction of arrow B; 
         FIG. 8  shows a schematic view similar to  FIG. 2  of an alternative embodiment of the instrument in a tissue gripping position; 
         FIG. 9  shows a view corresponding to  FIG. 8  of the instrument shown there with partly unfolded second tool element; 
         FIG. 10  shows a sectional view along line  10 - 10  in  FIG. 8 ; 
         FIG. 11  shows a schematic sectional view similar to  FIG. 10  of the second tool element folded up in a position as shown in  FIG. 9 ; 
         FIG. 12  shows a perspective schematic view of an alternative embodiment of a second tool element; 
         FIG. 13  shows an exploded view of a part of the second tool element shown in  FIG. 12 ; 
         FIG. 14  shows a sectional view along line  14 - 14  in  FIG. 12 ; 
         FIG. 15  shows a schematic sectional view similar to  FIG. 14  of the exemplary embodiment shown there with partly unfolded second tool element; 
         FIG. 16  shows a perspective schematic view similar to  FIG. 12  of another exemplary embodiment of a second tool element; 
         FIG. 17  shows an enlarged view of the second tool element from  FIG. 16  in a partly sloped position; 
         FIG. 18  shows a sectional view along line  18 - 18  in  FIG. 16 ; and 
         FIG. 19  shows a view similar to  FIG. 18  with partly sloped second tool element in a position, as it is shown in  FIG. 17 . 
     
    
    
     DETAILED DESCRIPTION 
     A surgical system for connecting body tissue is schematically shown in  FIG. 1  and is designated as a whole with reference number  10 . It comprises a surgical instrument  12  with two tool elements  14  and  16  which are movable in relation to one another. Further, the system  10  comprises a current generator in the form of an RF current generator  18 , which can be connected to the instrument  12  in another manner described in detail below. 
     The tool elements  14  and  16  form a part of a connecting means, provided as a whole with reference number  20 , for connecting body tissue. The first tool element  14  comprises an edge surface  22 , pointing in the distal direction, of an elongated, sleeve-like shaft  24  of the instrument  12 . Thus, the first tool element is arranged or formed at a distal end  26  of the instrument  12 . 
     The first tool element  14  comprises an RF electrode  28 . It is divided into at least two electrode segments  30 , into four electrode segments  30  in the exemplary embodiment schematically shown in  FIGS. 2 through 5 , which are electrically insulated from each other. The electrode segments  30  are designed as strip-shaped or essentially strip-shaped. The first tool element  14  defines a tool element surface  32  such that the RF electrode  28  forms a part of same. All in all, the tool element surface  32  is designed as flat and circular. 
     The four electrode segments  30  define two rows of electrodes  34  and  36 . Each row of electrodes comprises a part of the four electrode segments  30  each. As can be seen, for example, in  FIG. 5 , each electrode segment  30  has a first electrode segment section  38 , which forms a part of the first row of electrodes  34 , and a second electrode segment section  40 , which forms a part of the second row of electrodes  36 . The two rows of electrodes  34  and  36  have an overall curved design, whereby the electrode segment sections  38  and  40  define electrically conductive circular ring sections each. All in all, the at least two rows of electrodes, which are defined by four electrode segment sections  38  or  40  each, have a self-contained circular design. To be able to contact the electrode segments  30  in a desired manner, each electrode segment  30  is connected in an electrically conductive manner to a terminal contact  42  which is arranged in a connection area between the electrode segment sections  38 ,  40 . Even after tissues are connected by RF current feed, completely or essentially undamaged cells, from which new cell growth can start, remain behind between the rows of electrodes. In the long term, this makes possible in addition to connecting tissues by welding a permanent connection of the tissues due to the growing together of intact cells. 
     RF electrode  28  defines an electrode center line  44  running between the electrode segment sections  38  and  40 . Therefore, electrode segments  30  which are adjacent to one another are arranged offset to one another in a direction defined by the electrode center line  44 . All in all, the RF electrode  28  divided into four electrode segments  30  defines an electrode length  46 , whereby each of the four electrode segments  30  defines a segment length  48  that is shorter than the electrode length  46 . As shown, for example, in  FIG. 5 , electrode segments  30  extend over an angle range of approx. 140° and thus have a length that corresponds to approximately 40% of the electrode length  46 . Thus, the sum of all segment lengths  48  is, however, also approx. greater by a factor of 1.6 than the electrode length  46 . 
     RF terminal contacts  50 , which are connected in an electrically conductive manner, for example, via lines running in the shaft, to the electrode segments  30 , are arranged in the area of a proximal end of the shaft  24 . The number of RF terminal contacts  50  preferably corresponds to the number of electrode segments  30 , i.e., four RF terminal contacts  50  for the four electrode segments  30  of the first tool element  14 . 
     The second tool element  16  is designed as essentially disk-like and comprises an electrode element  52 , which can be moved in the direction of the first tool element  14  and away from same as well as parallel to a longitudinal axis  54  of the shaft  24  in the area of the tool elements  14 ,  16  which defines a shaft direction  56 . The tool elements  14 ,  16  are arranged displaceable in relation to one another, i.e., a distance  58  between the tool element surface  32  of the first tool element  14  and a tool element surface  60  of the second tool element  16  is variable. 
     The electrode element  52  comprises an RF electrode  29 , which corresponds to the RF electrode  28  in its design. This means that it also comprises four electrode segments  31 , which do not protrude over the tool element surface  60 . Two rows of electrodes  35  and  37  are likewise defined, whereby first electrode segment sections  39  define the row of electrodes  35  and second electrode segment sections  41  define the row of electrodes  37 . Terminal contacts  43  are likewise provided, which conductively connect an electrode segment section  39  to an electrode segment section  41  each for forming an electrode segment  31 . RF electrodes  28  and  29  are designed as mirror-symmetrical to a mirror plane running at right angles to the longitudinal axis  54  between the tool element surfaces  32  and  60 . In this way, pairs of electrode segments  62  are defined by an electrode segment  30  each and the corresponding electrode segment  31  lying opposite same. All in all, the exemplary embodiment shown in  FIGS. 1 through 5  thus comprises four pairs of electrode segments  62 . The electrode segments  30 ,  31  are not only geometrically similar, but also have the same size or essentially the same size. 
     The RF electrodes  28 ,  29  define a minimal distance  58  from one another in a position of proximity of the tool elements  14 ,  16 . The position of proximity is schematically shown in  FIG. 4 . In the position of proximity, the RF electrodes  28  and  29  lie opposite one another and point towards one another. 
     The electrode segments  31  can be connected in an electrically conductive manner to another four RF terminal contacts  50 , of which only two are shown in  FIG. 1  for the sake of clarity. The RF terminal contacts  50  may be connected to corresponding contacts  66  of the RF current generator  18  by means of corresponding connecting lines  64 . As already explained, the RF terminal contacts  50  are directly connected in an electrically conductive manner to the electrode segments  30 . To be able to connect the RF terminal contacts  50  to the electrode segments  31 , contact members  68 , which have a short cylindrical section  70  and a cone-shaped section  72  defining a free end, are arranged projecting at the shaft  24  or at the first tool element  14  pointing in the direction of the second tool element  16 . In a tissue connection position, as it is schematically shown, for example, in  FIG. 4 , i.e., in a position, in which tool elements  14  and  16  are located in the position of proximity, the free ends of the sections  72  of the contact members  68  extend into corresponding sleeve-like mounts  74  of the electrode element  52  and are in electrically conductive contact with same. Contact members  68  are in turn connected to the RF terminal contacts  50  along the shaft  24  via electrical lines (not shown). The mounts  74  are in turn connected in an electrically conductive manner to the terminal contacts  43 . In this way, an electrically conductive contact between the RF terminal contacts  50  and the electrode segments  31  can also be made in the proximity position or tissue connection position. 
     Of course, contact members  68 , which pass through the electrode segments  30  in the area of their terminal contacts  42 , are insulated from same, so that no short-circuits can occur. For this purpose, the sections  70  of the contact members  68  are preferably provided with an electrically conductive coating or shell. 
     In order to be able to move the tool elements  14 ,  16  of the instrument  12  in relation to one another, an actuating means  76  is arranged at a proximal end or end area of the instrument  12 . The actuating means  76  comprises two actuating members  78 , which are pivotable in relation to one another and which are movably coupled with a force transmission member  80  mounted movably in the interior of the shaft, such that as a result of the pivoting movement of the actuating members  78 , this is movable in the distal or proximal direction. 
     At its distal end, the force transmission member  80  defines a blind-hole-like mount  82 , into which a holding member  84  with a first free end can be inserted and can then be fixed in the mount  82 . The second free end of the essentially rod-shaped holding member  84  is immovably connected to the second tool element  16 . In this way, as a result of a displacement of the force transmission member  80  in the distal direction, the second tool element  16  can be moved away from the first tool element  14 . The instrument  12  is preferably designed, such that the second tool element  16  can be brought from a tissue gripping position, as it is schematically shown in  FIGS. 2 and 3  and in which the tool elements  14 ,  16  have a maximum distance  58  from one another, into the position of proximity or the tissue connection position by pivoting the actuating members  78  towards one another, which results in a movement of the force transmission member  80  in the proximal direction. 
     Furthermore, the instrument comprises a cutting means  86  for cutting tissue. The cutting means  86  comprises a cutting element  88  with a self-contained circular cutting edge  90 . The cutting edge  90  defines a cutting plane  92  sloped in relation to the longitudinal axis  54  of the instrument  12 . The cutting plane  92  is sloped by approx. 10° in relation to a reference plane running at right angles to the longitudinal axis  54 , which runs parallel to the tool element surfaces  32  and  33 . On the proximal side, another RF cutting terminal  94 , which in a variant of the instrument  12  is connected in an electrically conductive manner to the cutting element  88 , is provided at the shaft  24 . Thus, for example, a monopolar cutting means  86  can be implemented, whereby a neutral electrode would usually be applied for monopolar cutting at the body of the patient. A bipolar cutting means  86  is, for example, implemented by a ring electrode  96  being arranged opposite cutting edge  90  at the second tool element  16 , which is connected to another RF cutting terminal  94  via an electrically conductive connection (which is not shown in detail), which runs, for example, through the force transmission member  80  in a manner not shown. The ring electrode  96  itself may also be selectively segmented, for example, similar to the RF electrodes  28  and  29 . It would also be possible to use the RF electrode  29  as a counterelectrode instead of the ring electrode  96 . 
     The cutting element  88  is preferably mounted displaceably in relation to the two tool elements  14 ,  16 . The cutting edge  90 , which is designed as concentric about the longitudinal axis  54 , can thus be displaced in relation to the RF electrodes  28  and  29 . For actuating the cutting means  86 , a cutting actuating means  98  is provided with an actuating member  100  projecting from the proximal end of the instrument. This is mechanically coupled to the cutting element  88  via a mechanism (which is not shown), for example, another force transmission member running in the interior of the shaft  24 , such that, as a result of a movement of the actuating member  100 , the cutting element  88  is moved as well. The actuating member  100  is preferably arranged displaceably and rotatably in relation to the shaft  24 , such that the cutting element  88  can be not only displaced parallel to the longitudinal axis  54 , but also rotated in relation to same. 
     In order to be able to apply RF current to the electrode segments  30 ,  31  as desired, a control and/or regulating means  102  is provided with a switching means  104 . The control and/or regulating means  102  is preferably arranged in a housing of the RF current generator and forms a part of same. The switching means  104  is especially designed for the sequential application of an RF current to the electrode segments  30 ,  31 . The switching means  104  is especially used for controlling the contacts  66  as well as further contacts  106 , which can be connected to the RF cutting terminals  94  of the instrument  12  via further connecting lines  108 . In this way, the cutting means  86  can be operated in a monopolar or bipolar manner with the RF current generator  18 . For the monopolar operation, RF current is applied only to the cutting element  88  and a neutral electrode is arranged at the body of the patient as a counterelectrode. For bipolar cutting, especially a circular counterelectrode may be provided at the second tool element  16 , for example, in the form of the ring electrode  96 , such that an RF current can then flow between the counterelectrode and cutting element  88 . As an alternative, the RF electrode  29  may also be used as a counterelectrode. If a current feed of the cutting means  86  is entirely dispensed with, then this may also be used purely mechanically for cutting tissue and by means of the preferably sharpened cutting edge  90 . 
     The switching means  104  may further also be designed such that RF current can be simultaneously applied to at least two electrode segments  30 ,  31  of an RF electrode  28 ,  29 . It is advantageous here when another electrode segment  30 ,  31 , which is then currentless, however, is arranged between two electrode segments  30 ,  31 , to which RF current is applied simultaneously. For example, in this way the electrode segments  30  of the RF electrode  28  shown in  FIG. 5  lying opposite one another might be fed current simultaneously, whereby the two other electrode segments  30  then remain currentless. 
     In order to be able to individually adjust a current feed intensity and/or a duration of current feed for the individual electrode segments  30 ,  31 , the control and/or regulating means  102  is designed as comprising an adjusting means  110 . By means of the adjusting means  110 , for example, an intensity and/or a frequency of the RF current, just as a duration of current feed, can be adjusted. Moreover, the adjusting means  110  may optionally also be designed to be able to adjust current feed sequences individually. 
     Furthermore, the control and/or regulating means  102  preferably comprises a temperature measuring means  112  for measuring an electrode segment temperature and/or tissue temperature. Temperature measuring means  112  is especially used for supplying the control and/or regulating means  102  the controlled variables needed for an automatic regulation of a current feed of the RF electrodes  28 ,  29 , especially a temperature of the tissue, for example, indirectly via a temperature measurement of the electrode segments  30 ,  31 . For example, electrode segments  30 ,  31 , which are not fed current, may be used as measuring contacts for determining the temperature via a measurement of the tissue impedance. In this way, it can be guaranteed that the temperature needed for connecting the tissue in a desired and highly precise manner is achieved by the corresponding feed of current to the RF electrodes  28 ,  29 , but an undesired overheating of the tissues to be connected to one another is prevented. 
     Further, the control and/or regulating means  102  optionally comprises an impedance measuring means  113  for measuring a tissue impedance of tissue held between the tool elements  14  and  16 . The determination of the tissue impedance makes it possible, depending on its value, to regulate the RF generator  18 , especially the parameters of voltage, current or power provided by same. In this way, the energy to be introduced into same for connecting the tissues can be regulated in a simple and reliable manner. Especially the RF electrodes  28  and  29  can be used for measuring the tissue impedance. A measurement may also be performed between individual electrode segments  30  and  31 , which lie opposite one another. The tissue impedance measurement may take place selectively during the current feed of RF electrodes  28 ,  29  or when RF electrodes  28 ,  29  are just currentless. Thus, the change in the tissues can be monitored well and practically in real time and further energy input can be metered, stopped or specifically further permitted. 
     With the surgical system  10  described above, especially tubular tissues  116  can be connected to one another directly by being welded or sealed to one another by means of RF current. In particular, the procedure is, for example, as follows: 
     For making an end-to-end anastomosis of two tubular tissues  116 , as is necessary, for example, after a bowel surgery, in which a piece of the bowel is removed, free ends of the tissues  116  are brought towards one another, such that they lie against one another in a circular, flat manner, as shown, for example, in  FIGS. 3 and 4 , with their free ends pointing in the direction of the longitudinal axis. The free ends are then located between the two tool elements  14 ,  16 , such that the tissues  116  can be held together, being gripped between the tool elements  14 ,  16  in the tissue gripping position. 
     The tool elements  14 ,  16  are then moved towards one another into the tissue connection position, such that the electrode segments  31  are also connected in an electrically conductive manner to the RF terminal contacts  50  in the manner described above. For welding the tissues  116 , an RF current is now preferably applied to individual pairs of electrode segments  62 , which then flows over the tissue sections held between the tool elements  14 ,  16  and heats same. At a temperature of approx. 50° C. to approx. 80° C., and preferably approx. 65° C. to approx. 70° C., a change takes places in the cells, such that the tissues  116  bond to one another. The connection process is preferably carried out such that always only one pair of electrode segments  62  is simultaneously fed current, especially in a sequential succession. In this way, a circular connecting line  114  is produced, which is essentially predetermined by the RF electrodes  28 ,  29  or their electrode center lines  44 ,  45 . 
     The temperature can be much better controlled for connecting the tissues  116  and a destruction of the cells can be prevented by an RF current not being applied to all the RF electrodes  28 ,  29 . The electrode segments  30 ,  31  are preferably fed current one after the other, i.e., sequentially, such that the tissues  116  are welded to one another in sections along the connecting line  114 . Furthermore, a double connection between the tissues  116  is produced by the two-row arrangement of the electrode segment sections  38 ,  39 ,  40  and  41 , which can guarantee an optimal sealing and a permanent, stable connection of the tissues  116  to one another. 
     As an alternative to a sequential current feed, as already indicated above, electrode segments  30 ,  31  lying opposite one another may also be fed current simultaneously, as a result of which the time for connecting the tissues  116  can be cut in half in the exemplary embodiment schematically shown in  FIGS. 1 through 5 . 
     After connecting the tissues  116 , protruding tissue is removed by means of the cutting means  86 . In this case, the cutting means  86  is preferably used in a bipolar mode, i.e., the cutting element  88  and the ring electrode  96  are connected to the RF current generator  18  and an RF current is conducted over the two tissues  116  to cut the tissue. Due to the sloped cutting edge  90 , a defined cutting spark is produced, and precisely in the area in which the distance between the cutting edge  88  and the ring electrode  96  is minimal. Starting from this area, the cutting spark then travels automatically along the cutting edge  90  in both directions around in a circle until the tissue is completely severed. The use of the cutting means  86  in the bipolar mode of operation has especially the advantage that the tissues  116  are also simultaneously coagulated during the cutting in order to stop undesired bleeding directly during the cutting. 
     After connecting and cutting the tissues  116 , the instrument  12  can then be withdrawn from the body of the patient, for example, from his/her bowel, by withdrawing the shaft  24 . 
     Depending on the embodiment of the instrument  12 , the shaft  24  is preferably so long that both the actuating means  76  and the cutting actuating means  98  still protrude from the body of the patient during the use of the instrument  12 , so that they can be actuated by a surgeon. 
     As an alternative or in addition, the surgical system  10  may comprise, instead of the instrument  12 , also a surgical instrument, for example, in the form of an instrument  120  schematically shown in  FIGS. 6 and 7 . The instrument  120  comprises two branches  124  and  126  mounted on one another pivotable in relation to one another about a pivot axis  122 . Finger rings  128 ,  130 , which together define an actuating means  132  for actuating the instrument  120 , are formed at a proximal end of the branches  124 ,  126 . 
     Starting from free, distal ends  134  and  136  of the branches  124  and  126  are formed tool elements  138  and  140  pointing towards one another on the insides of same. The tool elements  138  and  140  have an identical design and lie opposite one another in a position of proximity of the ends  134  and  136  and have a minimal distance from one another in this position. Each tool element  138 ,  140  comprises an RF electrode  142 ,  144 , which have an identical and essentially U-shaped design. Each RF electrode  142 ,  144  comprises two electrode sections  146 , running parallel to one another and extending in a direction at right angles to the pivot axis  122 , as well as an electrode section  148  running at right angles to same, adjacent to the ends  134 ,  136 . 
     The structure of the RF electrodes  142 ,  144  is described in detail below, for example, in connection with  FIG. 7  based on the RF electrode  142 . 
     RF electrode  142  comprises a total of 30 electrode segments  150 , whereby 15 electrode segments each are arranged offset to one another in two rows of electrodes  152 ,  154  parallel to one another along each electrode section  146  and electrically insulated from each other. The electrode segments  150  have a linear and strip-shaped design. They define between them an electrode center line  156 , which likewise has a U-shaped design corresponding to the shape of the RF electrode  142 . Two other electrode segments  151 , which complete the rows of electrodes  152  or  154  of the electrode sections  146 , respectively, are arranged in the area of the electrode section  148 . Thus, the electrode segments  150  and  151  are arranged offset to one another in a direction defined by the electrode center line  156 . 
     To be able to apply an RF current to the electrode segments  150 ,  151 , these are each arranged in an electrically conductive manner with an RF terminal  158  in proximal end areas of the branches  124 ,  126  adjacent to the finger rings  128 ,  130 . The RF terminals  158  can be connected to the RF current generator  18  with corresponding connecting lines or cables. 
     Because of the identical design of the RF electrodes  142  and  144 , electrode segments  150  and  151  which are the same size or essentially the same size lie opposite one another and point towards one another in the position of proximity. They form a pair of electrode segments, which is designated as a whole with the reference number  168 . Thus, the instrument  120  comprises a total of 32 pairs of electrode segments  168 . 
     The tool elements  138  and  140  also define flat tool element surfaces  170 , which have a U-shaped design. The electrode segments  150  and  151  do not protrude over the tool element surface  170 . 
     The instrument  120 , which has an overall tong-shaped design, may likewise be used for connecting tissues, whereby these are held gripped between the tool elements  138 ,  140  and then are welded or sealed to one another by means of corresponding application of current to the electrode segments  150 ,  151 . As in connection with the function of the instrument  12  described, a current feed of the electrode segments  150  may be carried out sequentially for this, i.e., circulating in a U-shaped manner, after feeding an electrode segment  150  with current, the nearest electrode segment  150  of the adjacent row of electrodes  152 ,  154  is fed current until all electrode segments  150 ,  151  were fed current once. In this way, a two-row connecting line for connecting two tissues can be produced. As an alternative, a simultaneous current feed of two or even more electrode segments  150 ,  151  is also conceivable in the instrument  120 , whereby electrode segments  150 ,  151 , which are adjacent to one another, are preferably not fed current simultaneously, but rather preferably at least one, preferably two or three electrode segments  150 ,  151  remain currentless between electrode segments  150 ,  151  that are fed current simultaneously. 
     The instrument  120  may optionally also comprise a cutting means  160 , as it is schematically shown in  FIG. 6 . A slot  162  each is formed between the electrode sections  146  at the tool elements  138 ,  140 . A cutting element  164  with the cutting edge  166  pointing in the direction of the slot  162  of the branch  124  is held and can optionally be moved in relation to the tool element  136  in the slot  162  of the branch  126 . Thus, for example, the tissue held between the tool elements  138  and  140  can be cut already when the branches  124  and  126  are closed. Optionally, the cutting element  164  may also be used in monopolar or bipolar mode, whereby, for example, the RF electrode  142  can be used as a counterelectrode to the cutting element  164  in bipolar mode. For the monopolar operation, an RF current is applied only to the cutting element  164  and a neutral electrode is then arranged as a counterelectrode at the body of the patient. In both cases, the cutting element  164  is preferably also connected in an electrically conductive manner to a contact of the RF terminals  158 . 
       FIGS. 8 through 11  show a variant of the instrument  12  which is distinguished by the design of the second tool element which is designated with reference number  16 ′ in  FIGS. 8 through 11 . Tool element  16 ′ adopts a circular ring shape in an operating position, in which it can be brought into the position of proximity described above. It comprises two circular ring sections  180  and  182 , which extend each over an angle of approx. 180° in relation to the longitudinal axis  54 . Free ends of the circular ring sections  180 ,  182  are only half as wide as the circular ring sections  180 ,  182  in the remaining area and are used as bearing blocks  184  and  186 . Bearing blocks  184  and  186  are each provided with a cross hole  188  and  190 , into which a cylindrical rod  192  is inserted. Bearing blocks  184  lie against bearing blocks  186  on their side facing the longitudinal axis  54 . The rod  192  is fixed adapted to rotate in unison in the cross holes  190  of the circular ring section  182 . The cross hole  188  is dimensioned in its inside diameter such that the circular ring section  180  is pivotable in relation to the rod  192  about a pivot axis  242  defined by same and thus in relation to the circular ring section  182 . 
     The two circular ring sections  180  and  182  are each additionally coupled via rod-shaped connecting rod  194  with a holding member  84 ′, which defines a holding member longitudinal axis coinciding with the longitudinal axis  54 . The holding member  84 ′, similar to holding member  84 , is coupled or can be coupled with the force transmission member  80 , and in this way can be moved in relation to the shaft  24  in the distal and proximal direction. For the movable articulation of the connecting rod  194  at holding member  84 ′, the latter is provided in the area of its distal end with a slot  204 , which extends transversely to a longitudinal axis defined by the rod  192 . In this way, two legs  206  are formed, which are provided with an aligning cross hole  208 , into which a cylindrical mounting pin  210  is inserted adapted to rotate in unison. The connecting rods  194  are provided at their first ends with a mounting hole  212 , through which the mounting pin  210  extends and which has an inside diameter to make possible a pivoting movement of connecting rods  194  about a pivot axis defined by the mounting pin  210 . 
     Approximately on the proximal side of the slot  204 , a longitudinal slot or slotted hole  214 , which is passed through by the rod  192 , extends in the holding member  84 ′ further in the proximal direction. In this way, the rod  192  is defined and is displaceable parallel to itself in a direction parallel to the longitudinal axis  54 . A proximal end of the slotted hole  214  forms a proximal end stop for the rod  192 , a distal end  218  of the slotted hole  214  forms a distal end stop for the rod  192 . 
     An actuating mechanism  222 , which comprises a sleeve-like force transmission element  220 , whose inside diameter is adapted to the outside diameter of holding member  84 ′ and thus is displaceable on holding member  84 ′ in the distal and proximal direction, is used to move the rod  192 . The force transmission element  220  is, adjacent to its distal end  224 , provided with a hole  226 , which the rod  192  passes through. The rod  192  is rotatable in relation to the hole  226 . The actuating mechanism  222  can further form a part of the actuating mechanism  76  described above. This means that a movement of the rod  192  is possible, for example, even by a pivoting of the actuating members  100  in relation to one another. As an alternative, it would be conceivable to provide another actuating means similar to actuating mechanism  76 , which comprises one or two other actuating members, similar to the actuating members  100 , to implement specifically a relative movement between the force transmission element  220  and the holding member  84 ′. 
     On the top sides of the circular ring sections  180  and  182  are arranged two bearing blocks  228  each, which are parallel to one another and which, parallel to the cross hole  208 , are provided with holes  230 . Between the bearing blocks  228 , another free end of the connecting rod  194  each is pivotably mounted on the bearing shaft  200  inserted in the holes  230 . Due to the described arrangement of the connecting rods  194 , which may also be designated as articulating members, it is guaranteed that with one end at the second tool element  16 ′, they act on a point of action or hinge point, which is spaced away from the pivot axis  242 . 
     Using the actuating mechanism  222 , the second tool element  16 ′ can be brought from the operating position already mentioned, which is schematically shown in  FIGS. 8 and 10 , into the removal position, which is shown, for example, in  FIG. 11 .  FIG. 9  schematically shows an intermediate position, i.e., a position between the operating position and the removal position. As can be easily seen by a comparison of the two  FIGS. 10 and 11 , a surface area of a vertical projection of the second tool element  16 ′ is on a projection plane  234 , which runs at right angles to the longitudinal axis  54 , i.e., to the shaft direction in the area of second tool element  16 ′, is smaller in the removal position than in the operating position. This is achieved by a movement of the sleeve-like force transmission element  220  starting from the operating position, in which the rod  192  stops at the proximal end  216  and bottom sides  236  and  238  of the circular ring sections  180  and  182  extend parallel to the projection plane  234 . If the force transmission element  220  is moved in the distal direction, the rod  192  is forcibly guided in the slotted hole  214  in the distal direction. Due to the articulated connection of the circular ring sections  180  and  182  in relation to one another and via the two connecting rods  194  with the holding member  84 ′, the circular ring sections  180  and  182  pivot about the pivot axis  242  in the direction of the longitudinal axis  54 . The second tool element  16 ′ is in this way folded together or folded up. Thus, due to the articulated arrangement of the circular ring sections  180  and  182  by means of the connecting rods  194 , a folding mechanism  240  is formed for transferring the second tool element  16 ′ from the operating position into the removal position. 
     The design of the bottom sides  236  and  238  of the second tool element has not been mentioned up to now. This may have either a single, essentially continuous ring electrode, which forms a single counterelectrode to RF electrode  28  of the first tool element  14 . As an alternative, an RF electrode with two or more electrode segments  31 , preferably corresponding to RF electrode  29 , may also be formed on the bottom sides  236  and  238  similar to RF electrode  29 . This then makes possible a connecting of tissues  116  in the operating position in the manner described above. 
     After connecting the tissues, the folding mechanism  240  can then be actuated, for example, by the corresponding actuating of the described actuating mechanism  222 , as a result of which the holding member  84 ′ is moved in the distal direction. If the force transmission element  220  is, for example, arranged fixed in relation to the shaft  24 , then the second tool element  16 ′ can be automatically folded up by a movement in the distal direction of the force transmission member  80 . Due to the markedly reduced area requirement in the removal position, the second tool element can be guided through a connecting site formed by the connecting of the tissues  116  during the removal of the instrument  12 , and without expanding the connecting site, which is markedly more sparing then guiding the second tool element through the connecting site in the operating position. 
     It goes without saying that electrically conductive connections of electrode  29  to the RF terminal contacts  50  can be routed, for example, via the connecting rods  94  and the holding member  84 ′ to the RF terminal contacts  50  in the proximal end area of the shaft  24 . 
     Another variant of a second tool element is designated as a whole with the reference number  16 ″ in  FIGS. 12 through 15 . It replaces, for example, the above-described tool elements  16  and  16 ′ of the instrument  12 . 
     The second tool element  16 ″ has an essentially plate-like design with a slightly convex, curved outside  250  pointing in the distal direction. 
     A ring groove  252 , which is open pointing in the proximal direction, is formed on the bottom side of the second tool element  16 ″. In the center is formed an essentially circular recess  252 , in which an essentially cuboid bearing projection is arranged, which is designed as projecting coaxially to the longitudinal axis  54  in the proximal direction from the bottom side of second tool element  16 ″. The bearing projection  256  is provided with a cross hole  258 , which runs skew in relation to longitudinal axis  54 . Furthermore, a curved guide slot  260 , which is curved convexly pointing in the proximal direction, is formed at the bearing projection  256 . A proximal end of the bearing projection  256  has a rounded outer contour. 
     The second tool element  16 ″ is pivotably mounted on a sleeve-like holding member  84 ″. For this purpose, the holding member  84 ″ is provided with a cross hole  262 , which passes through a wall  264  of the holding member  84 ″ at two sites. A mounting pin  266  adapted to rotate in unison is inserted into the cross hole  262 . It simultaneously passes through the cross hole  258  such that the bearing projection  256  is pivotable about a pivot axis  284  defined by the mounting pin  266 . To be able to actuate a folding mechanism  270  provided also with the second tool element  16 ″, a force transmission element  268  is provided, which has an essentially rod-shaped design and the holding member  84 ″ passes through coaxially to the longitudinal axis  54 . From an end surface  272  on the distal side of the force transmission element  268 , two bearing journals  274  are arranged parallel to one another and projecting pointing in the distal direction, which are each passed through by an aligning hole  276 . Another mounting pin  278 , which is oriented parallel to the mounting pin  266 , is inserted adapted to rotate in unison into the holes  276 . An outside diameter of the mounting pin  278  is dimensioned such that it can pass through the guide slot  260  and can be moved in relation to same. 
     A proximal end  280  of the force transmission element  268  can preferably be coupled with the force transmission member  80 , such that the second tool element  16 ″ can also be moved as a result of a movement of same. 
     A circular electrode element  282 , which preferably comprises an RF electrode  29  in the manner as described above, which is not shown in detail in  FIGS. 12 through 15  for the sake of clarity, is inserted into the ring groove  252 . As an alternative, a simple, continuous ring electrode may also be formed at the electrode element  282 . 
     For transferring the second tool element  16 ″ from the operating position into the removal position, the force transmission element  268  is moved in the distal direction. Because of the specially curved guide slot  260 , the mounting pin  278  is forcibly guided in same and thus brings about a forcibly guided pivoting of the second tool element  16 ″ about the pivot axis  284 . Essentially, the second tool element  16 ″ can be pivoted about almost 90°, such that in this variant of the tool element  16 ″ as well, a vertical projection  232  of same onto the projection plane  234  in the removal position is smaller than in the operating position, as this is schematically shown in  FIGS. 14 and 15 . In this way, an overexpansion of the connecting site between the tissues  116  connected to one another is prevented in the removal position when removing the instrument  12 . 
     Another embodiment of a second tool element, which is provided as a whole with the reference number  16 ′″, is shown in  FIGS. 16 through 19 . It can be used in the instrument  12  instead of the previously described second tool elements  16 ,  16 ′ and  16 ″. 
     The second tool element  16 ′″ has an essentially plate-like design and comprises a disk  300 . Disk  300  is provided in its center with a transversely running, oblong, oval slot  302 . A hole  304  passes through the disk  300  somewhat laterally offset to its center, which lies in the area of the slot  302 . A mounting pin  306 , which likewise passes through the slot  302 , is inserted adapted to rotate in unison into the hole  304 . A distal end of a holding member  84 ″, which has a sleeve-like design, protrudes into the area of the slot  302 . On the side proximally from its end  308 , the holding member  84 ′″ is provided with a hole  310 , whose inside diameter is adapted to the outside diameter of the mounting pin  306  so that the mounting pin  306  is rotatable in same in relation to the hole  310 . All in all, this then makes possible a pivoting of the disk  300  about a longitudinal axis defined by the mounting pin  306 . 
     A folding mechanism  312 , which couples the disk  300  via a connecting rod  314  in an articulated manner with a distal end  316  of a force transmission element  318 , is used for the forcibly actuated pivoting of the disk  300 . The force transmission element  318  has an extended, rod-shaped section  320 , whose proximal end  322  can be coupled with the force transmission member  80 . The end  316  is thickened in a head-shaped manner against the section  320  and shaped almost cuboid. On one side of same is formed a lateral open slot  324 . Further, a cross hole  326  is provided, which passes through the slot  323  transversely. A mounting pin  328  is inserted adapted to rotate in unison into the cross hole  326 . The rod-shaped connecting rod  314  is likewise provided with a hole  330  and is mounted pivotably on the mounting pin  328 . Adjacent to an opposite end of the connecting rod  314  is provided another hole  332 . It is used for mounting the connecting rod  314  on another mounting pin  334 . This is inserted into another hole  336  of the disk  300 . The hole  336  is oriented parallel to the hole  304  and arranged outside the slot  302  adjacent to an edge  338  of the disk  300 , and lying opposite the hole  304  in relation to the longitudinal axis  54 . Starting from the edge  338 , a groove  342 , into which the end of the connection rod  314  with its hole  332  dips, is provided on a top side  340  of the disk  300 . In this way, the connecting rod  314  is mounted in an articulated manner on the mounting pin  334 . Thus, the connecting rod  314  with an end at the second tool element  16 ′″ acts on a point of action or hinge point, which is spaced away from the pivot axis  344  defined by the longitudinal axis of the mounting pin  306 . 
     The folding mechanism  312  is actuated by the force transmission element  318  being moved in the distal direction. The result of this is that the connecting rod  314  is bent in relation to the disk  300 . The further the force transmission member  318  is moved in the distal direction, the further the connecting rod  314  draws the area of the disk  300  in the distal direction, at which the groove  342  is provided. In an extreme position, the disk  300  is then aligned almost parallel to the longitudinal axis  54 . All in all, it is thus also possible in the second tool element  16 ′″ to embody a removal position, in which a vertical projection  232  of same onto the projection plane  234 , which runs at right angles to the longitudinal axis  54 , is smaller than in the operating position. 
     An RF electrode  29  may likewise be arranged or formed at the second tool element  16 ′″ in a form as described above in the second tool element  16 . As an alternative, it is also conceivable to provide a self-contained, circular electrode, which is not divided into electrode segments. Similar to how the second tool element  16 ″ comprises the electrode element  282 , electrode elements may likewise be provided in second tool elements  16 ′ and  16 ′″, for example, in the form of the electrode element  282  or else even the electrode element  52 . 
     As already mentioned above in connection with the second tool element  16 ′, the RF electrodes provided at the second tool elements  16 ″ and  16 ′″ may usually be connected to the RF terminal contacts  50  by providing corresponding electrically conductive connections at the instrument  12 . 
     All above-described first and second tool elements  14 ,  16 ,  16 ′,  16 ″,  16 ′″, as well as  138  and  140  are preferably composed of either electrically conductive or electrically insulating components. Also conceivable are components, which are partly electrically conductive or partly electrically insulating. The components themselves may especially be produced completely from electrically conductive or electrically insulating materials, whereby the electrically insulating components may also be produced from an electrically conductive material, which is especially provided with an electrically insulating outer shell or coating. Especially plastics, which still have sufficient strength at the temperatures occurring during the use of the surgical system  10 , may be used as electrically insulating or nonconductive materials. For example, both thermoplasts and duroplasts are suitable. As an alternative, ceramic material may also be used as insulating material. The components of the tool elements  14 ,  16 ,  16 ′,  16 ″,  16 ′″, as well as  138  and  140  may especially be made of a ceramic. A ceramic to be used has especially the advantage over many plastics that it also has a sufficient stability at very high temperatures. The RF electrodes  28  and  29  are preferably made of a metal or a metal alloy. As an alternative, the use of electrically conductive ceramics is also conceivable for forming the RF electrodes  28  and  29 , provided that they meet the requirements of the application of RF current. 
     The tool elements  14 ,  16 ,  16 ′,  16 ″,  16 ′″, as well as  138  and  140  may, for example, be produced as described below. The individual parts, units or components of the tool elements  14 ,  16 ,  16 ′,  16 ″,  16 ′″, as well as  138  and  140  may especially be produced separately and then be joined together, for example, by bonding. As an alternative, it is, for example, also possible to insert the electrically conductive parts of the RF electrodes  28  and  29  as inserts into a plastics injection molding die and to injection-mold with a plastic. As already mentioned, the electrodes may be made from a metal or an electrically conductive ceramic. In a segmenting of the RF electrodes  28  and  29  as described above, a corresponding number of electrically conductive electrode segments made of a metal or a metal alloy or an electrically conductive ceramic must, for example, then be inserted into the plastics injection molding die before injection molding with a suitable plastic. 
     In a purely ceramic design of the tool elements  14 ,  16 ,  16 ′,  16 ″,  16 ′″, as well as  138  and  140 , a ceramic powder injection molding process is offered, e.g., the so-called “2K CIM” technology, a two-component micro-ceramic powder injection molding process. Here, two different ceramics are injected in an injection molding process, which form the electrically conductive and electrically insulating parts in the finished tool elements  14 ,  16 ,  16 ′,  16 ″,  16 ′″, as well as  138  and  140 . After the injection molding, two different ceramics are sintered together. They may be, for example, an Al 2 O 3  ceramic and a mixed ceramic made of Al 2 O 3  and TiN.