Abstract:
An electrosurgical instrument for minimally invasive surgery, the instrument including two gripping parts which can be brought together into a gripping direction or moved apart counter to the gripping direction. At least one gripping part includes three or more electrically conductive sections, electrically insulated relative to each other. Each electrically conductive section may be separately connected to a high frequency (RF) current generator such that each electrically conductive section can be configured in various electrical configurations by the RF current generator.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is the U.S. national stage of claims priority to PCT/EP2010/004470, filed Jul. 21, 2010 and published as WO 2011/018153, which claims priority to DE102009037613.5, filed Aug. 14, 2009. 
     
    
     FIELD OF THE DISCLOSED EMBODIMENTS 
       [0002]    The disclosed embodiments relate to surgical instruments, and more particularly to electrosurgical pincettes or forceps, for minimally invasive surgery. 
       BACKGROUND OF THE DISCLOSED EMBODIMENTS 
       [0003]    European Patent EP 1 151 723 B1, by the Applicant, discloses a surgical instrument that includes two gripping parts that can be brought together in a gripping direction or moved apart counter to the gripping direction. Each of the gripping parts has a first inner and a second outer limb with a bending region, the limbs being at a distance from each other in the gripping direction. The surgical instrument&#39;s inner limbs of the gripping parts are arranged inside a guide sleeve and can be moved in the longitudinal direction of the guide sleeve relative to the outer limbs of the gripping parts in such a manner that, with a movement of the limbs relative to each other in their longitudinal direction, the respective gripping part can be moved in the gripping or counter-gripping direction. One limb of the first gripping part can be connected to a first connector of an RF (high frequency) current generator and the inner limb of the second gripping part can be connected to a second connector of the RF generator, and the limbs are electrically insulated from each other. 
         [0004]    Such surgical instruments are used in minimally invasive surgery, for example, for grasping tissue, small vessels or similar such materials. Like forceps or pincettes, such an instrument includes movable gripping parts that can be brought together or moved apart for gripping in a gripping direction or a counter gripping direction. Due to their small dimensions, the instruments can preferably be used in the working channel of an endoscope. 
         [0005]    The instrument in accordance with EP 1 151 723 B1 has proven itself in clinical applications. However, the need for further improvement has arisen. Therefore, it is the object of the disclosed embodiments to provide an improved electrosurgical instrument that offers further increased efficacy and safety when handled in practical applications. 
       BRIEF SUMMARY OF THE DISCLOSED EMBODIMENTS 
       [0006]    The disclosed embodiments improve the working options of the physician by dividing at least one of the two gripping parts of the instrument into functionally different sections. For this purpose, the first and/or the second gripping part have several conductive sections extending in the longitudinal direction of the instrument, each of these sections being associated with a pair of inner and outer limbs. In one embodiment, the individual pairs of inner and outer limbs may be electrically insulated from each other and may be connected separately to an RF current generator. Referring to this embodiment and considering different modifications of the connection of the limbs (and thus the associated sections of the respective gripping part), it is possible to implement different field configurations in the distal effective region of the instrument with the use of an RF current generator. 
         [0007]    In one embodiment, each of the first and/or second gripping parts has three or more insulated conductive sections and pairs of inner and outer limbs. In particular, it is possible to provide exactly three conductive sections and pairs of limbs in order to produce different configurations of the electrical field between the gripping parts. 
         [0008]    Another embodiment provides that the distance between the inner and the outer limbs of the associated pair of limbs of a gripping part divided into sections be greater than the distance of the limbs associated therewith. As a result of this, the circular or elliptical cross-section of the guide sleeve of the limbs can be optimally used in a statically advantageous manner, and an instrument exhibiting strong gripping forces and low-loss force transmission can be implemented. 
         [0009]    Another embodiment provides that the surface of the first and/or second gripping part respectively facing the other gripping part be inclined or curved, at least in sections, in such a manner that, in a brought-together state, a gap of longitudinally uneven width is formed between the gripping parts. The result of the application of a voltage to the first and the second gripping parts with such a gap results in a linearly or non-linearly varying electrical field strength of the electrical field formed between the first and the second gripping parts in the longitudinal direction. This, too, increases the working options with the suggested instrument on the part of the physician in coping with different clinical situations. 
         [0010]    Another embodiment provides that at least one of the sections of a gripping part be movably supported in the gripping part or opposite thereof. In particular, the configuration is such that a section with an inclined or curved surface is movably supported in the respective gripping part in such a manner that it can be moved separately toward or away from the other gripping part. This, among other things, makes possible a certain uncoupling between the mechanical and electrothermal (coagulating) functions of the instrument. 
         [0011]    Another embodiment provides that the movably supported section having a curved surface be accommodated in the respective gripping part in such a manner that the gripping part performs a rolling-off movement relative to an opposite surface of the other gripping part when the instrument is moving towards a brought together state. In doing so, in the process of closing the instrument, the point of the smallest distance between the opposing gripping part surfaces moves in the direction of the distal end of the instrument. Each of the first and the second gripping parts has three insulated sections with one associate pair of inner and outer limbs, and the respective movably supported sections have an inclined or curved surface. 
         [0012]    Another disclosed embodiment provides that the movable section be guided within the gripping part in the gripping direction, in particular by an adjacent stationary section of the same gripping part. As a result of this, it is possible to perform precisely controlled mechanical functions such as, for example, a mechanical severing operation. 
         [0013]    Another embodiment of the instrument includes a guide for laterally guiding the first and the second gripping part. The guide is active, at least in the mostly closed part of the instrument. The guide for lateral guidance may be provided on one or more of the plurality of insulated sections of the one or more gripping parts that are divided into sections. As a result, it is possible to largely preclude potential jamming of the gripping parts or of the sections thereof relative to each other, as well as unintentional contusing of tissue grasped with the instrument. 
         [0014]    Another embodiment provides that at least one insulating section acts as a spacer between two insulated conductive sections for the adjustment of a prespecified minimum distance between the opposing conductive sections in a brought-together state of the instrument. Consequently, it is possible to prevent short circuits when the instrument is handled, such short circuits otherwise occurring when a vessel or other tissue fails to be grasped and the conductive gripping parts or sections thereof can come into direct contact with each other. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a longitudinal sectional view of a surgical instrument; 
           [0016]      FIG. 2  is a longitudinal sectional view of a surgical instrument; 
           [0017]      FIGS. 3A-3C  are perspective and sectional views of the interior construction of the front part (distal part) of the surgical instrument of  FIGS. 1 and 2 , with  FIGS. 3A and 3B  showing the instrument in a brought-together state, and  FIG. 3C  showing the instrument in a moved-apart state; 
           [0018]      FIG. 4  is a perspective illustration of an instrument in accordance with a disclosed embodiment; 
           [0019]      FIGS. 5A to 5C  are schematic cross-sectional views showing and instrument in accordance with a disclosed embodiment looking in the longitudinal direction; 
           [0020]      FIGS. 6A to 6D  are schematic diagrams showing various electrical field configurations of an electrosurgical instrument in accordance with a disclosed embodiment; 
           [0021]      FIGS. 7A to 7D  are schematic side views showing various opening and closing states of an instrument in accordance with a disclosed embodiment; 
           [0022]      FIG. 8  is a schematic cross-sectional view of the distal end of an instrument looking in the longitudinal direction in accordance with a disclosed embodiment; and 
           [0023]      FIGS. 9A and 9B  are partial side views of an instrument in two different states in accordance with a disclosed embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    In the description hereinafter, the same reference signs are used for the same parts and for parts having the same function. 
         [0025]      FIG. 1  shows a complete side view of the surgical instrument  1  with the instrument tip  2  and a manipulative handle  3 .  FIG. 2  shows a longitudinal sectional view of the surgical instrument shown by  FIG. 1 . 
         [0026]    Referring to,  FIG. 2 , the design of the manipulative handle  3  and, in particular, its mode of function is particularly well recognizable. First limbs  11  and  21 , extend from a first and a second gripping part  10  and  20 , respectively, through a guide sleeve  30  and a tube  40  up to an actuating device  4  that is supported in the manipulative handle  3  and is disposed for bringing the gripping parts  10  and  20  together in a gripping direction or apart counter to the gripping direction. A helical spring  60  is used to push the actuation device  4  out of the handle  3  against an abutment, whereupon a pulling force in the longitudinal direction of the tube  40  and the guide sleeve  30  is exerted on the first limbs  11  and  21  of the gripping parts  10  and  20 , so that the gripping parts  10  and  20  are brought together. This corresponds to the inoperative position of the instrument  1 . 
         [0027]    By applying pressure on the actuation device  4  or by pushing the actuation device  4  into the manipulative handle  3  while the helical spring  60  is being compressed, a pushing force is exerted on the first limbs  11  and  21 . The pushing force can move the first limbs  11  and  21  away from the manipulative handle  3  in the longitudinal direction of the tube  40  and the guide sleeve  30 . This causes a torque at the instrument tip  2  around the mounts of the second limbs  12  and  22  ( FIGS. 3A-3C ) on the guide sleeve. The torque causes the gripping parts  10  and  20  projecting from the guide sleeve  30  at the instrument tip in the bending regions  13 ,  14  and  23 ,  24  ( FIGS. 3A-3C ) to bend outward, thus causing the gripping parts  10  and  20  to move apart counter to the gripping direction. 
         [0028]    A tissue may be enclosed by the two gripping parts  10  and  20  and be grasped by removing the pressure from the actuation device  4 . Without any manipulative pressure, the helical spring  60  again pushes the actuation device  4  out of the manipulative handle  3  thus applying a pulling force on the first limbs  11  and  21 . The pulling force brings together the gripping parts  10  and  20  in the gripping direction and enables a grasping or gripping of the tissue. In doing so, the tissue is clamped between the two gripping surfaces of the gripping parts. Then, when the bending regions ( 13 ,  14 ,  23 , and  24 ) have been pre-bent in the opening direction (see  FIG. 7 ), with appropriate dimensioning of the helical spring  60 , the entire system can be held together only due to the thusly occurring preliminary tension, i.e., also without any adhesion. 
         [0029]      FIG. 3A  is a perspective view of a disclosed embodiment with the gripping parts brought together.  FIG. 3A  is different from  FIGS. 1 and 2  in that the two gripping parts  10  and  20 , the guide sleeve  30 , and its cap section  32  are shown. In addition, the grasping surfaces of the two gripping parts  10  and  20  are smooth, i.e., they are shown without profile. 
         [0030]    The first inner limbs  11  and  21 , as well as the second outer limbs  12  and  22 , of the gripping parts  10  and  20  are completely arranged inside the guide sleeve, essentially preventing any soiling or contamination and ensuring precise guidance. However, because it cannot be precluded that contaminants such as fluids, blood or similar substances enter into the instrument due to capillary action, the instrument is provided with a rinsing channel (not shown) for the purpose of cleaning. 
         [0031]    The second limbs  12  and  22  have projections  33  and  34 , respectively, that prevent a movement of the second limbs  12  and  22  in the longitudinal direction into the guide sleeve. The projections  33  and  34  are arranged in recesses of the cap section  32  that are provided for this purpose so that, in addition, a relative rotation of the gripping parts  10  and  20  into the guide sleeve  30  is prevented. Furthermore, the projections are disposed to fix the second limbs  12  and  22  in position on the guide sleeve  30 . To accomplish this, it is possible to glue the projections  33  and  34 , for example to the guide sleeve  30  and/or the cover cap  32 , or to clamp the projections in the recesses of the cover caps  32 . 
         [0032]      FIG. 3B  shows a partial sectional view of an embodiment shown by  FIG. 5A . The guide sleeve  30  consists of an insulating material, for example a plastic material. The first inner limbs  11  and  21  of the two gripping parts  10  and  20  have a design that is longer than that of the second outer limbs  12  and  22 . The projections  33  and  34  of the second limbs  12  and  22 , respectively, abut against the guide sleeve  30 , such that they cannot be moved into the guide sleeve. 
         [0033]    In order to move the gripping parts  10  and  20  apart or together, the longer first limbs  11  and  21  are moved in the longitudinal direction of movement indicated by the double arrow  35 . 
         [0034]      FIG. 3C  shows an embodiment of the instrument with the gripping parts moved apart, in which case the limbs  13 ,  14 ,  23 ,  24  are pre-bent in the opening direction of the gripping parts  10 ,  20 . Thus, in the inoperative position, the gripping parts of the instrument are moved apart. When the two inner or first limbs  11  and  21  are moved in the longitudinal direction away from gripping parts  10  and  20 , gripping parts  10  and  20  are brought together. The movement causes a torque about the affixed two limbs  12  and  22 , respectively, as a result of which the gripping parts  10  and  20  are bent in the bending regions  13  and  14  or  23  and  24  of the limbs  11  and  12  or  21  and  22 , so that the gripping parts  10  and  20  are brought together in the gripping direction  37 . The gripping surfaces  15  and  25  of the first and second gripping parts  10  and  20 , respectively, can be seen well. At least one of the two gripping surfaces  15  or  25  may be configured as a cutting edge, the instrument  1  can also be used for cutting tissue or as a scissors.  FIG. 3C  shows an embodiment of profiled gripping surfaces  26  indicated in dashed lines. 
         [0035]      FIG. 4  is a perspective illustration of the distal end of an electrosurgical instrument  101 . The instrument includes a guide sleeve  130  that is mostly inserted in a tube  140  and includes two limb arrangements projecting from the guide sleeve, each of the limb arrangements terminating in gripping parts  110  and  120 , respectively, the gripping parts representing the distal end of the instrument  101 . 
         [0036]    Each gripping part  110 ,  120  is an assembly of a total of five individual (not individually identified here) material blocks that are connected to each other by means of screws  116 . The outer elements and the center element are made of conductive material, and each includes associate inner and outer limbs. For the sake of greater clarity,  FIG. 4  identifies these limbs only for one of the outer elements, i.e., with reference numbers  113  (inner limb) and  114  (outer limb) on the first gripping part  110  and with reference numbers  123  (inner limb) and  124  (outer limb) on the second gripping part  120 . 
         [0037]    The two blocks located between the outer elements and the center element of the gripping parts  110 ,  120  may comprise insulating material and may not have any associate limbs. A spacer block  117  is provided on each of the insulating interlayers in order to keep the metallic components of the gripping parts  110 ,  120  at a prespecified distance from each other, even if there is no vessel or tissue between the gripping parts, in order to avoid a short circuit when the RF voltage is switched on and the instrument  101  is in a brought-together state. The mode of movement of the instrument during the closing and opening process corresponds to the mode of operation of the instrument shown by  FIGS. 1 to 3C , the instrument having been described farther above. 
         [0038]      FIGS. 5A to 5C  illustrate an aspect of the disclosed embodiments in that  FIG. 5A  shows a cross-section of the limb design of the instrument in  FIG. 3  and  FIG. 5B and 5C  show a limb design of the instrument  101  and  101 ′, respectively. Whereas, in the instrument  1  in  FIG. 5A , each gripping part (not shown) is assigned only one single inner or outer limb  13 ,  23  or  14 ,  24 , each of the instruments  101  and  101 ′ includes three pairs of limbs, respectively, i.e.,  113   a / 114   a,    113   b / 114   b,    113   c / 114   c  or  123   a / 124   a,    123   b / 124   b  and  123   c / 124   c.  The instrument  101 ′ as in  FIG. 5C  is similarly constructed; however, in the center of the guide sleeve  130 ′ a rinsing channel  150 ′ is provided, and the arrangement of the limbs  113 ′,  114 ′ or  123   b ′,  124   b ′ associated with the center element of the lateral gripping parts is slightly modified in order to create space for this rinsing channel  150 ′. The rinsing channel  150 ′ can be used as a suction channel for evacuating fluids that must be removed from the treatment region or also as a rinsing channel for supplying fluid to the treatment region. The channel may also be used for removing or supplying a gas, or also for inserting an additional instrument. 
         [0039]      FIGS. 6A to 6D  show schematic cross-sectional views of the gripping elements  110  and  120 . The elements are grasping a biological tissue T, and various circuitry configurations of each of the electrically conductive gripping element components (not separately marked), i.e., the connection to three poles, pole  1 , pole  2 , and pole  3  of an RF current supply are shown. Each of  FIGS. 6A to 6D  shows the configuration of the lines of electric flux passing through the tissue T and, therein, trigger various electrothermal and electrochemical effects, depending on the specific configuration of the lines of electric flux. These effects are not discussed in detail here as the embodiment shows that the division of the gripping elements into respectively three conductive components allows a plurality of such configurations. 
         [0040]      FIGS. 7A to 7D  are side views of the distal end of a first instrument ( FIG. 7A ) and a second instrument ( FIGS. 7B to 7D ), showing the operation of disclosed embodiments. Whereas, in the case of the instrument  101  as in  FIG. 7A , the side surfaces of the first and the second gripping parts  110 ,  120  extend parallel to each other in a brought-together state, the corresponding surfaces  110   a ′ or  120   a ′ of the first gripping part  110 ′ and the second gripping part  120 ′ of a modified instrument  101 ′ are curved. 
         [0041]    The (not illustrated) actuation mechanism acts in a manner such that, with the progressive closing of the instrument in the sequence shown in  FIGS. 7B to 7D , a rolling-off movement takes place between the surfaces  110   a ′,  120   a ′ of the gripping parts  110 ′ and  120 ′, the surfaces facing each other. In the course of this movement, as symbolized by the location of the jagged arrow in  FIGS. 7C and 7D , the point of the greatest electrical field strength migrates from the proximal end of the gripping parts in the direction of their distal ends. This can offer advantageous options for surgical use, e.g., the use of the instrument for a cutting operation in the manner of the action of a mechanical scissors. This is important for the movement shown in  FIGS. 7B to 7D  that a pushing force, as well as a pulling force, can be applied to at least the inner limbs. 
         [0042]      FIG. 8  is a schematic cross-sectional view of the distal end of an instrument  201 . In a first gripping part  210 , as well as in a second gripping part  220 , two stationary outer metal parts  210   a,    210   c  or  220   a,    220   c  each are firmly embedded in a carrier body  210   d  or  220   d , whereas a center element  210   b  or  220   b  is separately supported in a movable manner in the carrier body. The carrier body  210   d  or  220   d  may be an insulating material such as plastic. In addition, the opposing surfaces of the center elements  210   b,    220   b  are provided with a cutting edge. Consequently, referring to the embodiment shown by  FIGS. 7B to 7D  and the embodiment described hereinabove, this embodiment makes possible a holding and cutting of vessels or biological tissue with a pulling force, as well as with a pressure force, that can be applied to the inner limbs. 
         [0043]      FIGS. 9A and 9B  show another embodiment detailing the two different states of movement of only one of the two gripping parts of an instrument  301 . The gripping part  310  includes a stationary part  310   a  and at least one movable part  310   b  that is configured in one piece with an inner and an outer limb  313 ,  314 , respectively, and can be moved relative to the stationary part  310   a  into a grasping or cutting direction indicated by a double arrow when pushing forces or pulling forces are applied to the inner  313  and/or outer  314  limbs. The stationary part  310   a  is provided with guide pins  310   c,  and the stationary part  310   a  is provided with corresponding elongated holes  310  for engagement and for the sliding guidance of the guide or slide pins  310   c.  As a result of this arrangement, it is possible to perform particularly precise severing operations with the use of the appropriately configured instrument. 
         [0044]    The implementation of the disclosed embodiments is not restricted to the examples described above and the emphasized aspects, but is rather likewise possible in a plurality of modifications lying within the scope of expert procedure.