Abstract:
The invention relates to a bipolar electrosurgical instrument comprising a handle and a tool head. In the case of bipolar instruments, at least two mutually separate conducting paths must be provided within the instrument to supply the bipolar tool head. Reliable electrical insulation of these conducting paths relative to one another is often associated with a high cost in known electrosurgical instruments, such as scissors and clamps, since these instruments have a crossed joint. The present invention solves this problem in that the tool head is connected to the handle without crossing over itself.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to an electrosurgical instrument. 
         [0002]    In high-frequency surgery (HF surgery), alternating current is conducted at high frequency through the human body in order to damage or cut tissue in a targeted manner. An essential advantage over conventional cutting techniques with a scalpel is that, simultaneous with the cutting, suppression of bleeding can take place by closing the affected vessels (coagulation). A distinction is made between a high-frequency generator, which generates the relevant alternating current, and the electrosurgical instrument by means of which the current is applied to the tissue. The electrosurgical instruments which are frequently used are electrosurgical scissors and electrosurgical clamps. These instruments perform a certain double function, since they provide both conventional mechanical clamping and cutting and electrical coagulation and cutting by means of the high-frequency currents. 
         [0003]    The electrosurgical instruments described above belong to the class of bipolar electrosurgical instruments. The tool heads of the relevant instruments have two poles between which the alternating current flows. Taking the example of electrosurgical scissors, a first blade can be supplied with the current in a manner that is electrically separated from a second blade. The circuit is completed between the two blades by the tissue to be cut. In order to ensure good functioning of these bipolar electrosurgical instruments, reliable insulation of the electrical conducting paths in the corresponding electrosurgical instruments is necessary. In this regard, the mechanical joints of conventional electrosurgical instruments prove to be particularly problematic, since crossing-over and contacting of the relevant conducting paths occurs at the mechanical joints. 
         [0004]    The electrosurgical instruments described above are sufficiently well known from U.S. Pat. No. 6,406,475 B1 and U.S. Pat. No. 5,324,289. In order to separate the respective conducting paths from one another, it is proposed therein that insulation be provided at the mechanical joints. For reliable insulation of the two conducting paths, high demands are placed on the form of insulation, which consequently makes production complex and expensive. 
         [0005]    A further disadvantage of known electrosurgical instruments is that process-controlled production of a large product range is very complex and expensive. It may be, for example, that different surgeons place different demands on the associated handles of essentially the same instrument on account of the differing anatomy of their hands. 
         [0006]    In light of this prior art, it is an object of the present invention to develop an electrosurgical instrument such that it can be operated reliably and practically and that it can be produced economically and efficiently. 
       SUMMARY OF THE INVENTION 
       [0007]    In particular, the aim is achieved with an electrosurgical instrument comprising a handle with a first handle member and a second handle member and a tool head having a first tool limb and a second tool limb, wherein the first and second tool limbs are each attached with a first pivot joint to an at least partially insulating joint bearing, wherein the first handle member, together with the first tool limb, forms a first conducting path and the second handle member, together with the second tool limb, forms a second conducting path which is electrically separated from the first conducting path. The handle members are each attached with a second pivot joint to the joint bearing without crossing over. The tool limbs are also fastened with the second pivot joints without crossing over, the first tool limb being coupled via a first coupling to the first handle member such that a pivot movement about the second pivot joint of the first handle member results in a contrary rotary movement about the first pivot joint of the first tool limb. The second tool limb is coupled via a second coupling to the second handle member such that a pivot movement about the second pivot joint of the second handle member results in a contrary rotary movement about the first pivot joint of the second tool limb. 
         [0008]    A central concept of the invention is that the individual conducting paths of the electrosurgical instrument are arranged adjacent and essentially parallel to one another and are therefore automatically separate from one another. This advantage is achieved by providing additional pivot joints which avoid the need for mechanical crossing of the handle members and the tool limbs. A similar principle of pivot joints and coupling arrangement is known from commercially available bolt cutters. Additionally, by this means, advantageous force transmission between the handle members and the associated tool limbs can be achieved. An arrangement of this type can easily be produced by automated means and ensures reliable separation of the conducting paths. 
         [0009]    It is conceivable to mount the first pivot joints and the second pivot joints such that they are each rigidly connected to one another, although the rigid connections of the first pivot joints are freely movable relative to those of the second pivot joints and the tool limbs are connected via a non-elastic coupling to the handle member. It is advantageous, however, if the pivot joints are all rigidly connected to one another. A change in length in the electrosurgical instrument caused by the pivot joints and their movement, which could be problematic during an operation, is thereby avoided. The rigid connection should be chosen such that the pivoting ability of the pivot joints about their respective axes is not influenced. 
         [0010]    An advantageous expression of the joint bearing is that it comprises two insulator plates between which the pivot joints are arranged. The axes of the pivot joints are therefore arranged substantially perpendicularly to the insulator plates. The pivot joints can thus be configured in a simple manner, wherein reliable insulation is ensured between the individual pivot joints, in particular between the first pivot joint of the first tool limb against the first pivot joint of the second tool limb and of the second pivot joint of the first handle member against the second pivot joint of the second handle member. 
         [0011]    Preferably, an insulator web is provided between the tool limbs and between the handle members in the region of the pivot joints, in order to insulate the conducting paths relative to one another. This insulator web therefore extends substantially parallel to the first and the second conducting paths between the respective first and second pivot joints. The insulation of the conducting paths relative to one another is thereby increased. Furthermore, the first and second coupling can be chosen so that mechanical movement of the first coupling on the second coupling is possible. In order to avoid direct contact, the insulator web can function as a mechanical separation and/or as a type of stopper. 
         [0012]    Preferably, the insulator web is connected to the joint bearing, in particular with at least one of the two insulator plates. The T-profile thereby produced can be made easily and in one piece. Together with the second insulator plate, an H-profile is formed wherein, on one side of the insulator web, the first conducting path and, on the other side, the second conducting path, run separately from one another, separated by the insulating H-profile. 
         [0013]    Preferably, the electrosurgical instrument comprises a non-conducting synchronisation device, in particular between the two first pivot joints and/or between the second pivot joints, for mechanical coupling of the first pivot joints. The mechanical coupling has the effect that a rotation of the first pivot joint of the first tool limb results in a contrary rotation of the first pivot joint of the second tool limb and vice versa. The synchronisation device therefore ensures that none of the tool limbs can be moved independently of the other. This results in an improved operating capability of the instrument. For the construction of this synchronisation device, inter alia, the insulator web can be used wherein said web preferably has devices for accommodating toothed gears attached to the first pivot joints. 
         [0014]    A plurality of conducting paths can be provided in the first and the second handle member, although it is preferable if each handle member comprises an electrical connection for an electrical conducting path. 
         [0015]    Preferably, the tool limbs each comprise a groove in which a projection of the handle member engages in order to form the first or the second coupling. The coupling is therefore configured as an open joint wherein, on movement of the tool limb, the projection of the first handle member engages in the groove of the first tool limb and the projection of the second handle member engages in the groove of the second tool limb to different depths. Each coupling can be configured single-toothed. 
         [0016]    Alternatively, the pivot joints can comprise toothed gears whose pivot point coincides with the pivot axis of the respective pivot joint. The mutually engaging teeth then serve as the coupling. Herein, the toothed gear of the first pivot joint of the first tool limb engages in the toothed gear of the second pivot joint of the handle member and the toothed gear of the first pivot joint of the second tool limb engages in the toothed gear of the second pivot joint of the second handle member. 
         [0017]    Preferably, the couplings are made from electrically conductive material and comprise a part of the first or second conducting path. Therefore the mechanical coupling simultaneously serves as an electrical coupling and the circuit is configured to be simple and reliable. 
         [0018]    It is advantageous if the tool head and the handle are made from metal and are partially covered with an insulating layer. The individual parts of the tool head and of the handle are therefore conductive in their interior and can be used, respectively, for forming the first and second conducting paths. The insulating layer provides protection against unwanted electric short-circuits. 
         [0019]    According to the invention, the problem as set out above is also solved through a type series for electrosurgical instruments. The type series includes at least two tool heads and/or at least two handles which are mutually connectable via the pivot joints and the coupling. 
         [0020]    The concept also exists of providing a type of building block system wherein various different tool heads can be combined with different handles. The connection of these elements is carried out by means of the pivot joints and the couplings. 
         [0021]    Preferably the handle members, and particularly a handle member length of the different handles are configured to be different. Therefore, for example, depending on the properties of the handle member, different amounts of pressure can be applied with the same tool head. It is also conceivable that any finger holes on the handle members could be varied in order to produce an instrument specifically for the individual surgeon. 
         [0022]    The tool heads preferably comprise at least one tool head for cutting and at least one tool head for clamping. Thus, during machine production, a plurality of similar components can be used for different electrosurgical instruments, such as scissors and clamps. The production process is thereby made more economical and the instruments can be better individualised. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The invention will now be described in greater detail by reference to exemplary embodiments which are illustrated in the drawings, in which: 
           [0024]      FIG. 1   a  shows an electrosurgical clamp according to the invention; 
           [0025]      FIG. 1   b  shows the tool head of the electrosurgical clamp of  FIG. 1   a;    
           [0026]      FIG. 1   c  shows a detail view of the joint bearing of the electrosurgical clamp of  FIG. 1   a;    
           [0027]      FIG. 2  shows the electrosurgical clamp of  FIG. 1   a  in the closed condition; 
           [0028]      FIG. 3   a  shows the electrosurgical clamp of  FIG. 1   a  with an enclosed coupling bearing; and 
           [0029]      FIG. 3   b  shows a detail view of the enclosed coupling bearing of  FIG. 3   a.    
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    In the description below, the same reference signs are used for the same and similarly acting parts. 
         [0031]      FIG. 1   a  shows an electrosurgical clamp according to the invention. The instrument comprises a handle  20  having a first handle member  21  and a second handle member  22  for holding the electrosurgical instrument in the hand and a tool head  10  for grasping and clamping tissue. The handle  20  and the tool head  10  are rigidly connected to one another via an insulating joint bearing  30 . In order to elucidate the structure of the joint bearing  30 , the joint bearing  30  is shown open in  FIGS. 1   a ,  1   b ,  1   c  and  2 . The tool head  10  comprises a first tool limb  11  and a second tool limb  12 , each of which comprises, on the side remote from the joint bearing, a grasping surface for receiving the tissue. The clamp according to the invention is a bipolar electrosurgical instrument. This means that the tool head  10  or, more precisely, the grasping surfaces, form two mutually electrically separate poles. These poles are connected by means of a first conducting path  41  (see  FIG. 2 ) and a second conducting path  42  to the electrical current circuit of a high frequency generator. As shown schematically in  FIG. 2 , these conducting paths  41 ,  42  run separately and parallel along the longitudinal direction of the electrosurgical instrument or the clamp. In order to ensure this, the tool limbs  11 ,  12  and the handle members  21 ,  22  are made from electrically conductive material. For the electrical connection to the high frequency generator, the handle members  21 ,  22  each have an electrical terminal  40 . 
         [0032]    For the defined movement of the electrosurgical instrument, the clamp has four pivot joints  35 ,  35 ′,  36 ,  36 ′ which are mounted on the joint bearing  30  (see  FIGS. 1   b ,  1   c ). The first tool limb  11  forms around its first pivot joint  35  a rocker-like device. The first pivot joint  35  represents the pivot point about which a front tool section  16  and a rear tool section  17  of the first tool limb  11  are pivotable. This rear tool section  17  is in engagement with a front handle section  26  of the first handle member  21 . Similarly to the first tool limb  11 , the first handle member  21  also forms a rocker-like device wherein the front handle section  26  and a rear handle section  27  are mounted pivotable about the second pivot joint  36  of the first handle member  21 . 
         [0033]    The second tool limb  12  and the second handle member  22  are substantially mirror images of the first tool limb  11  and the first handle member  21  and are arranged on the joint bearing  30 . The second tool limb  12  therefore comprises a front tool section  16 ′ and a rear tool section  17 ′, which are mounted pivotable about the first pivot joint  35 ′. The second handle member  22  has on one side of the second pivot joint  36 ′ a front handle section  26 ′ and on the other side a rear tool section  27 ′. The rear handle section  17 ′ of the second tool limb  12  is in engagement with the front handle section  26 ′ of the second handle member  22 . 
         [0034]    If the rear handle sections  27 ,  27 ′ are moved toward one another in this symmetrical arrangement, a rotation movement about the second pivot joints  36 ,  36 ′ takes place. The rotation movements of the two second pivot joints  36 ,  36 ′ are directed mutually opposed. By means of a first coupling  51  and a second coupling  51 ′, this rotation movement is inverted and transmitted to both the first pivot joints  35 ,  35 ′. The front tool sections  16 ,  16 ′ are moved toward one another. The tool head  10  is closed. 
         [0035]    According to the invention, the force transmission from the first handle member  21  to the first tool limb  11  and from the second handle member  22  to the second tool limb  12  can be adapted for any desired application by variation of the length of the front handle sections  26 ,  26 ′. Naturally, the length of the rear tool sections  17 ,  17 ′ must be chosen accordingly. 
         [0036]    According to the invention, the first coupling  51  and the second coupling  51 ′ each comprise a groove  14  or  14 ′ and a projection  24  or  24 ′ which engage in one another (see  FIG. 1   c ). In order, during the rotation movements of the pivot joints  35 ,  35 ′,  36 ,  36 ′ described above, to prevent contacting of the first coupling  51  with the second coupling  51 ′, the joint bearing  30  comprises an insulator web  31 . This insulator web  31  lies perpendicularly to a bearing base  34  and forms a T-profile therewith. The insulator web  31  extends centrally between the couplings  51 ,  51 ′ such that contact between said couplings is prevented and the conducting paths  41 ,  42  are always insulated relative to one another. 
         [0037]      FIG. 3   a  shows the medical clamp according to the invention of  FIGS. 1   a  and  2 . However, the joint bearing  30  is enclosed in this case. The enclosure is formed by a bearing cover  33 . 
         [0038]    As shown by  FIGS. 3   a ,  3   b , the joint bearing  30  comprises the bearing cover  33 , the bearing base  34  and the insulator web  31 . The bearing cover  33  is arranged parallel to the bearing base  34 . In an enclosed condition of the joint bearing  30 , these elements therefore comprise an H-profile. 
         [0039]    The design of the individual pivot joints  35 ,  35 ′,  36 ,  36 ′ is the same in each case. A bolt is fed through an opening in the bearing base  34  through the respective handle member  21 ,  22  or the respective tool limb  11 ,  12  to an opening in the bearing cover  33 . The tool limbs  11 ,  12  and handle members  21 ,  22  are therefore pivotable about the respective bolt. Since the entire joint bearing  30  is made from electrically insulating material, for example plastics, the two conducting paths  41 ,  42  are electrically screened from one another. 
         [0040]    In another exemplary embodiment, the joint bearing  30  is only partially made from electrically insulating material and comprises part of the first and second conducting paths  41 ,  42 . In this exemplary embodiment, the bearing cover  33  has two substantially parallel electrically conductive regions. The first electrically conductive region runs between the first pivot joint  35  of the first tool limb  11  to the second pivot joint  36  of the first handle member  21 , the second region runs from the first pivot joint  35 ′ of the second tool limb  12  to the second pivot joint  36 ′ of the second handle member  22 . In the first conducting path  41 , therefore, the electric current initially flows through the first handle member  21 , then in sections through the joint bearing  30  to the first tool limb  11 . Similarly, the current flows in the second conducting path  42  through the second handle member  22 , a section of the joint bearing  30  and the second tool limb  12 . The electrical contact between the tool limbs  11 ,  12  and the joint bearing  30 , in particular the respective electrically conductive region of the bearing cover  33 , is created by direct contact and through the bolts of the pivot joints  35 ,  35 ′,  36 ,  36 ′. The electrical contact between the handle members  21 ,  22  and the joint bearing  30  and the electrically conductive region of the bearing cover  33  is also provided in a similar manner. 
         [0041]    In a further exemplary embodiment, the first pivot joints are synchronised. For this purpose, the insulator web  31  is not connected to the remainder of the joint bearing  30 . Rather, the insulator web  31  has teeth along its longitudinal direction on both sides in which toothed gears mounted on the first pivot joints  35 ,  35 ′ engage. On movement of the handle members  21 ,  22  or the tool limbs  11 ,  12  coupled thereto, the toothed gears of the first pivot joints  35 ,  35 ′ rotate about the pivot axis of the pivot joints  35 ,  35 ′ and displace the insulator web  31  within the joint bearing  30  along the longitudinal direction of the insulator web  31 . Each pivot movement of one of the two first pivot joints  35 ,  35 ′ is therefore automatically transmitted to the other one of the first pivot joints  35 ,  35 ′. 
         [0042]    In another embodiment, the electrosurgical instrument is constructed substantially identically to the preceding exemplary embodiment. Based on another embodiment of the tool head  10 , in particular the front tool sections  16 ,  16 ′, this electrosurgical instrument is particularly well suited to parting or cutting tissue. As distinct from the previously described electrosurgical clamp, the tool head does not have gripping surfaces, but scissor blades, which enable mechanical cutting. During an operation, the mechanical effects and the electrical effects therefore go together and enable simultaneous parting and eroding or coagulation of tissue. 
       REFERENCE SIGNS 
       [0000]    
       
         
           
               10  Tool head 
               11  First tool limb 
               12  Second tool limb 
               14 ,  14 ′ Groove 
               16 ,  16 ′ Front tool section 
               17 ,  17 ′ Rear tool section 
               20  Handle 
               21  First handle member 
               22  Second handle member 
               24 ,  24 ′ Projection 
               26 ,  26 ′ Front handle section 
               27 ,  27 ′ Rear handle section 
               30  Joint bearing 
               30  Insulator web 
               33  Bearing cover 
               34  Bearing base 
               35 ,  35 ′ First pivot joint 
               36 ,  36 ′ Second pivot joint 
               40  Electrical terminals 
               41  First conducting path 
               42  Second conducting path 
               51  First coupling 
               51 ′ Second coupling