Patent Publication Number: US-2015080887-A1

Title: Surgical device using energy

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation application of PCT Application No. PCT/JP2013/065262, filed May 31, 2013 and based upon and claiming the benefit of U.S. Provisional Application No. 61/654,431, filed Jun. 1, 2012, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a surgical device configured to apply energy to a biological tissue as a treatment target, thereby treating the biological tissue. 
     2. Description of the Related Art 
     For example, each of US 2006/0217709 A1 and U.S. Pat. No. 6,500,176 B1 discloses a surgical device that can pinch a biological tissue to give a treatment. Of these examples, U.S. Pat. No. 6,500,176 B1 discloses that a surface of an electrode and an outer surface of the same are formed into a continuous flat surface. 
     In general, when energy is applied to a biological tissue in a state that the biological tissue is held by a surgical device having an openable/closable treatment section, thereby treating the biological tissue, a fluid containing water vapor, a body fluid and the like is produced from the biological tissue. Such a fluid has a high temperature, and hence when it flows to the outside of the treatment section, the biological tissue is prone to thermal damage. Therefore, for example, in US 2008/0195091 A1, a groove is formed in a treatment section to surround an outer edge of an energy discharge section such as an electrode, whereby a fluid flows into a space formed by the groove. 
     BRIEF SUMMARY OF THE INVENTION 
     One aspect of a surgical device including a treatment section according to the present invention, configured to apply energy to a biological tissue as a treatment target, and treat the biological tissue as the treatment target, wherein the treatment section includes: first and second jaws which are relatively openable/closable to each other to enable holding and releasing the biological tissue including the treatment target and its surrounding tissue; an energy discharge section which is provided on at least one of the first and second jaws, and which is configured to give energy for a treatment to the biological tissue as the treatment target; a groove which is provided on at least one of the first and second jaws and outside close to the energy discharge section, and which is configured to receive a fluid generated from the biological tissue as the treatment target when the energy is discharged from the energy discharge section to the biological tissue as the treatment; a pair of first holding sections in which the energy discharge section is provided on at least one of the pair of first holding sections, the pair of first holding sections being configured to hold the biological tissue as the treatment target, and configured to define a first virtual plane as midway between surfaces of the first holding sections configured to hold the biological tissue as the treatment target when the first and second jaws are closed; and a pair of second holding sections which form outer edges of the first and second jaws, which is apart from the energy discharge section at outer side of the groove, and which is configured to define a second virtual plane different from the first virtual plane as midway between surfaces of the second holding sections configured to hold and press the surrounding tissue of the biological tissue as the treatment target when the first and second jaws are closed such that a flowing direction of the fluid generated from the biological tissue as the treatment target is configured to be changed when the fluid is flown from the first virtual plane to the second virtual plane through the groove, such that a flow path of the fluid from the inner side to the outer side of the second holding sections through the first and second virtual planes is increased than through the first virtual plane so as to apply a flow path resistance to the fluid, and such that the groove is configured to collect the fluid. 
     Advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  is a schematic view showing a treatment system using energy according to a first embodiment; 
         FIG. 2  is a schematic block diagram of the therapeutic treatment system according to the first embodiment; 
         FIG. 3  is a schematic view showing output states of energies from a high-frequency energy output circuit and a thermal energy output circuit as energy sources in the treatment system according to the first embodiment; 
         FIG. 4A  is a schematic lateral cross-sectional view of a treatment section of a surgical device in the treatment system according to the first embodiment; 
         FIG. 4B  is a schematic lateral cross-sectional view of the treatment section of the treatment device in the treatment system according to the first embodiment at a position indicated by reference numeral  4 B in  FIG. 4A ; 
         FIG. 5A  is a schematic lateral cross-sectional view showing a state that a biological tissue as a treatment target and its surrounding tissue are gripped by the treatment section of the surgical device in the treatment system according to the first embodiment; 
         FIG. 5B  is a schematic lateral cross-sectional view showing a state that the biological tissue as the treatment target and its surrounding tissue are gripped by the treatment section of the surgical device in the treatment system according to the first embodiment at a position denoted by reference numeral  5 B in  FIG. 5A ; 
         FIG. 6A  is a schematic view showing that the surgical device according to the first embodiment is a bipolar type; 
         FIG. 6B  is a schematic view showing that the surgical device according to the first embodiment is a monopolar type; 
         FIG. 7  is a schematic lateral cross-sectional view of a treatment section of a surgical device in a treatment system according to a first modification of the first embodiment; 
         FIG. 8  is a schematic lateral cross-sectional view of a treatment section of a surgical device in a treatment system according to a second modification of the first embodiment; 
         FIG. 9  is a schematic lateral cross-sectional view of a treatment section of a surgical device in a treatment system according to a third modification of the first embodiment; 
         FIG. 10  is a schematic lateral cross-sectional view of a treatment section of a surgical device in a treatment system according to a forth modification of the first embodiment; 
         FIG. 11  is a schematic lateral cross-sectional view of a treatment section of a surgical device in a treatment system according to a fifth modification of the first embodiment; 
         FIG. 12  is a schematic lateral cross-sectional view of a treatment section of a surgical device in a treatment system according to a sixth modification of the first embodiment; 
         FIG. 13  is a schematic view showing a treatment system using energy according to a second embodiment; 
         FIG. 14A  is a schematic longitudinal cross-sectional view showing a state that a main body side treatment section and a separation side treatment section of a surgical device are engaged and the separation side treatment section is separated and opened with respect to the main body side treatment section in the treatment system according to the second embodiment; 
         FIG. 14B  is a schematic longitudinal cross-sectional view showing a state that the main body side treatment section and the separation side treatment section of the surgical device are engaged and the separation side treatment section is moved closer and closed with respect to the main body side treatment section in the treatment system according to the second embodiment; 
         FIG. 14C  is a schematic view showing a surface of the main body side treatment section of the surgical device in the treatment system according to the second embodiment; 
         FIG. 15A  is a schematic longitudinal cross-sectional view showing a state that the separation side treatment section is moved closer and closed with respect to the main body side treatment section of the surgical device in the treatment system according to the second embodiment at a position denoted by reference numeral  15 A in  FIG. 14B ; 
         FIG. 15B  is a schematic longitudinal cross-sectional view showing a state that a separation side treatment section is moved closer and closed with respect to a main body side treatment section of a surgical device in a treatment system according to a first modification of the second embodiment at the position denoted by reference numeral  15 A in  FIG. 14B ; 
         FIG. 15C  is a schematic longitudinal cross-sectional view showing a state that a separation side treatment section is moved closer and closed with respect to a main body side treatment section of a surgical device in a treatment system according to a second modification of the second embodiment at the position denoted by reference numeral  15 A in  FIG. 14B ; 
         FIG. 15D  is a schematic longitudinal cross-sectional view showing a state that a separation side treatment section is moved closer and closed with respect to a main body side treatment section of a surgical device in a treatment system according to a third modification of the second embodiment at the position denoted by reference numeral  15 A in  FIG. 14B ; and 
         FIG. 15E  is a schematic longitudinal cross-sectional view showing a state that a separation side treatment section is moved closer and closed with respect to a main body side treatment section of a surgical device in a treatment system according to a fourth modification of the second embodiment at the position denoted by reference numeral  15 A in  FIG. 14B . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Modes for carrying out the present invention will now be described hereinafter in detail with reference to the drawings. 
     First Embodiment 
     A first embodiment will now be described with reference to  FIG. 1  to  FIG. 6B . 
     As shown in  FIG. 1 , a treatment system  10  using energy according to this embodiment includes a surgical device (an energy treatment device)  12  and an energy source  14  that gives energy to the surgical device  12 . A foot switch  16  having a pedal  16   a  that switches ON/OFF of the energy given to the surgical device  12  is connected to the energy source  14 . The surgical device  12  is electrically connected to the energy source  14  through a first cable  18   a  formed by bundling lead wires or signal wires, and the energy source  14  is electrically connected to the foot switch  16  through a second cable  18   b  formed by bundling lead wires or signal wires. The foot switch  16  can input a signal to the energy source  14  by, e.g., an operation of the pedal  16   a , and the energy source  14  can control the energy given to the treatment device  12  based on, e.g., an operation of the pedal  16   a  of the foot switch  16 . 
     As shown in  FIG. 2 , the energy source  14  has a control section  22 , a high-frequency energy output circuit  24 , a heating member drive circuit  26 , a display section  28 , and a speaker  30 . 
     Here, the high-frequency energy output circuit  24  in the energy source  14  is controlled by the control section  22  so that it gives high-frequency energy to later-described electrodes  72  and  74  of the treatment device  12  to generate heat from a biological tissue L held between the electrodes  72  and  74 , and the biological tissue L is denatured by this thermal energy. The heating member drive circuit  26  in the energy source  14  is controlled by the control section  22  so that it supplies energy to heating members (resistance heating heaters)  82  and  84  to generate heat therefrom, transfers this heat (thermal energy) to the electrodes  72  and  74 , and also transfers the heat (the thermal energy) to the biological tissue L to dehydrate the biological tissue L. That is, the surgical device  12  according to this embodiment enables the thermal energy to act on the biological tissue L and gives a treatment to the biological tissue L. 
     As the display section  28 , it is preferable to use, e.g., a touch panel so that it can be used for displaying a state of the energy source  14  or configuring various kinds of settings. Further, the speaker  30  is controlled so that it can inform of ON/OFF of an output from the high-frequency energy output circuit  24  or the heating member drive circuit  26  with the use of sound. 
     The control section  22  of the energy source  14  can control a supply time and so on in the case of supplying high-frequency energy (thermal energy) using the later-described electrodes  72  and  74  of the treatment device  12  and the thermal energy using the later-described heating members  82  and  84  to the biological tissue L. The control section  22  controls the high-frequency energy output circuit  24  to output the appropriate high-frequency energy for a time t1 by pressing down the pedal  16   a  of the foot switch  16  and to stop the output as shown in  FIG. 3 , and then controls the speaker  30  to generate the sound so that an operator can be informed of end of a treatment using the later-described electrodes  72  and  74 . Furthermore, the control section  22  gives a treatment using the high-frequency energy, then controls the heating member drive circuit  26  to output the appropriate thermal energy for a time t2 and to stop the output, and thereafter controls the speaker  30  to generate the sound so that the operator can be informed of the end of the treatment using the later-described heating members  82  and  84 . It is to be noted that a time t3 during which the treatment using the high-frequency energy is switched to the treatment using the thermal energy may be 0, or an appropriate time, e.g., several seconds may be taken. 
     The control section  22  may switch the setting for outputting the appropriate high-frequency energy for the time t1 with the use of the high-frequency energy output circuit  24  to a setting for outputting the high-frequency energy using a change in biological information (e.g., impedance or a phase difference) of the measurable biological tissue L by the electrodes  72  and  74  based on the setting in the display section  28 , and the output of the high-frequency energy may be stopped when one of both the members (the time and the biological information) is reached ahead of the other. 
     As shown in  FIG. 1 , the surgical device  12  includes a treatment section  42  that gives a treatment to the biological tissue L, an inserting section  44 , and an operating section  46 . 
     As shown in  FIG. 4A , the treatment section  42  includes a pair of openable/closable jaws (first and second jaws)  52  and  54  as a holding section for a biological tissue, and energy discharge sections  62  and  64  arranged on the jaws  52  and  54 . In this embodiment, the energy discharge sections  62  and  64  are depicted to have a flat plate shape in  FIG. 4A , but various shapes are acceptable. It is to be noted that, for example, ceramics, a resin having heat-resisting properties and insulation properties, an insulated metal material, or the like is appropriately used for the first and second jaws  52  and  54 . 
     Opening/closing of the first and second jaws  52  and  54  shown in  FIG. 1 , i.e., opening/closing of first and second treatment sections  42   a  and  42   b  is operated by an opening/closing lever  46   a  in the operating section  46 . When the opening/closing lever  46   a  is operated, the first and second jaws  52  and  54  are opened/closed by well-known means such as a wire or a rod arranged in the inserting section  44 . It is to be noted that one of the first and second jaws  52  and  54  alone may be configured to move, or both of them may be configured to move. That is, the first and second jaws  52  and  54  can be relatively opened/closed. In this embodiment, a description will be given as to an example in which, with respect to one (the first jaw  52 ) of the first and second jaws  52  and  54 , the other (the second jaw  54 ) is configured to move. 
     As shown in  FIG. 4A , the energy discharge sections  62  and  64  have the high-frequency electrodes  72  and  74  and the heating members  82  and  84  that are arranged on the high-frequency electrodes  72  and  74 , respectively. Of these members, the first jaw  52 , the high-frequency electrode  72 , and the heating member  82  (the first energy discharge section  62 ) form the first treatment section  42   a , and the second jaw  54 , the high-frequency electrode  74 , and the heating member  84  (the second energy discharge section  64 ) form the second treatment section  42   b.    
     Heating elements may be used for each of the heating members  82  and  84 , and a plate-like heater may be used for the same. It is preferable to arrange or bury the heating members  82  and  84  on or in back surfaces of the electrodes  72  and  74  if each of the heating members  82  and  84  is formed of the heating elements and preferable to arrange the heating members  82  and  84  on the back surfaces of the electrodes  72  and  74  if each of the heating members  82  and  84  is the plate-like heater. It is also preferable for each of the heating members  82  and  84  to have a bar shape that is long in a longitudinal direction of the electrodes  72  and  74  or a direction orthogonal to the longitudinal direction. 
     The high-frequency electrodes  72  and  74  face each other and are used as holding surfaces  62   a  and  64   a  for the biological tissue L as the treatment target. That is, the holding surfaces (a first holding section)  62   a  and  64   a  are formed as a holding section (the first holding section) of the biological tissue L as the treatment target. Therefore, when the high-frequency energy is given to the electrodes  72  and  74  in a state that the biological tissue L is held between the holding surfaces  62   a  and  64   a  of the electrodes  72  and  74 , the biological tissue L can be denatured by the thermal energy that has heated the biological tissue L. Further, the electrodes  72  and  74  are made of a material having excellent thermal conductivity. Therefore, when heat is generated from the heating members  82  and  84 , the heat (thermal energy) is transferred to the electrodes  72  and  74 , and the heat (the thermal energy) can be further transferred to the biological tissue L held between the holding surfaces  62   a  and  64   a  of the electrodes  72  and  74 . Therefore, the holding surfaces  62   a  and  64   a  also function as treatment surfaces for the biological tissue L. 
     The first jaw (the lower jaw)  52  of the treatment section  42  in this embodiment is, e.g., a fixed type, and the second jaw (the upper jaw)  54  is a movable type that can be opened/closed with respect to the first jaw  52 . 
     Each of the first and second jaws  52  and  54  is formed into a substantially tabular shape that is long in a direction (a longitudinal direction) parallel to the longitudinal direction of the inserting section  44  and has a width direction orthogonal to the longitudinal direction formed to be smaller than the longitudinal direction. 
     The first jaw  52  has a main body  102 , a concave portion  104  which is formed on the inner side of an outer edge of a main body  102  (the center in the longitudinal direction and the width direction is preferable) and in which the energy discharge section  62  (i.e., the electrode  72  and the heating member  82 ) is arranged, a groove  106  which is formed in the main body  102  and arranged to surround an outer side of the concave portion  104 , and an outer edge portion (a barrier portion)  108  that is formed in the main body  102  and arranged to surround an outer side of the groove  106 . The concave portion  104 , the groove portion  106 , and the outer edge portion  108  are formed at positions where they face the second jaw  54 . It is to be noted that the outer edge portion  108  may be integrally formed with the main body  102  of the first jaw  52  or may be formed as a separate body. The outer edge portion  108  forms a holding section (a second holding section) that faces a later-described outer edge portion  128  and holds a surrounding tissue S of the biological tissue L as the treatment target. 
     In this embodiment, although the surface  62   a  of the electrode  72  is formed as a flat surface, it may have irregularities. 
     As shown in  FIG. 4B , the outer edge portion  108  itself has an end portion (the uppermost end)  108   a  on its inner side (a side close to the energy discharge section  62 ) placed above an edge portion  108   b  on its outer side (a side apart from the energy discharge section  62 ), and the end portion  108   a  on the inner side and the end portion  108   b  on the other side are smoothly continuous with each other. Therefore, a surface, which faces the later-described outer edge portion  128  of the second jaw  54 , of the outer edge portion  108  of the first jaw  52  is formed as an inclined surface (a second holding surface)  112 . 
     The groove  106  is used for receiving, in cooperation with the outer edge portion  108 , a later-described liquid produced in the biological tissue L as the treatment target when energy is applied to the biological tissue L as the treatment target. It is to be noted that the groove  106  is closed or communicates on a distal end side of the first jaw  52 , and it is opened on a proximal end side of the first jaw  52 . That is, the groove  106  can allow the later-described fluid to flow to the proximal end side (the inserting section  44  side) of the treatment section  42 . 
     As shown in  FIG. 4A , the second jaw  54  includes a main body  122 , a concave portion  124  which is formed on the inner side of an outer edge of the main body  122  (the center in the longitudinal direction and the width direction is preferable) and in which the energy discharge section  62  (i.e., the electrode  74  and the heating member  84 ) is arranged, a groove  126  which is formed in the main body  122  and arranged on the outer side of the concave portion  124 , and an outer edge portion (a barrier portion)  128  that is formed in the main body  122  and arranged on the outer side of the groove  126 . The concave portion  124 , the groove portion  126 , and the outer edge portion  128  are formed at positions where they face the first jaw  52 . It is to be noted that the outer edge portion  128  may be integrally formed with the main body  122  of the second jaw  54  or may be formed as a separate body. 
     Further, the energy discharge sections  62  and  64 , the groove portions  106  and  126 , and the outer edge portions  108  and  128  of the first and second jaws  52  and  54  face each other, and they move closer to or away from each other by moving the first and second jaws  52  and  54  closer or away from each other. It is to be noted that the outer edge portions  108  and  128  facing each other may abut on each other or may have a gap therebetween and not abut on each other when the first and second jaws  52  and  54  are closed each other in a state that a biological tissue is not held. The energy discharge sections  62  and  64  and the gap portions  106  and  126  that face each other are apart from each other when the first and second jaws  52  and  54  are closed in a state that a biological tissue is not held. That is, the first and second jaws  52  and  54  are formed in such a manner that the surfaces  62   a  and  64   a  of the electrodes  72  and  74  do not come into contact with each other when the first and second jaws  52  and  54  are closed. 
     In this embodiment, the surface  64   a  of the electrode  74  is formed as a flat surface, but it may have irregularities. 
     As shown in  FIG. 4B , the outer edge portion  128  itself includes an end portion  128   b  on its inner side (a side close to the energy discharge section  64 ) placed above an end portion (the lowermost end)  128   a  on its outer side (a side apart from the energy discharge section  64 ), and the end portion  128   b  on the inner side and the end portion  128   a  on the other side are smoothly continuous with each other. Therefore, a surface, which faces the outer edge portion  108  of the first jaw  52 , of the outer edge portion  128  of the second jaw  54  is formed as an inclined surface (a second holding surface)  132 . In addition, it is preferable for the inclined surface  112  of the outer edge portion  108  in the first jaw  52  to be parallel to or substantially parallel to the inclined surface  132  of the outer edge portion  128  in the second jaw  54 . 
     The groove  126  is used for receiving, in cooperation with the outer edge portion  128 , the later-described liquid produced when energy is applied to the biological tissue L as the treatment target. It is to be noted that the groove  126  is closed or communicates on a distal end side of the second jaw  54 , and it is opened on a proximal end side of the second jaw  54 . That is, the groove  126  can allow the later-described fluid to flow to the proximal end side (the inserting section  44  side) of the treatment section  42 . 
     Here, as shown in  FIG. 4B , assuming that a thickness of the outer edge portion  108  of the first jaw  52  is t and an angle of the inclined surface  112  relative to an inner surface of the outer edge portion  108  is θ (0 degrees&lt;θ&lt;90 degrees), a width W of the inclined surface  112  of the outer edge portion  108  can be expressed as W=t/sin θ. That is, when the angle θ of the inclined surface  112  is 90 degrees, the width W of the inclined surface  112  of the outer edge portion  108  coincides with the thickness t of the outer edge portion  108 . Therefore, the width W of the inclined surface  112  of the outer edge portion  108  according to this embodiment is t/sin θ larger in accordance with the angle θ of the inclined surface  112  than that in a case where the angle θ is 90 degrees. Therefore, when the inclined surfaces  112  and  132  are formed, a contact area of the biological tissue L as the treatment target with respect to the surrounding tissue S can be increased as compared with a case where the angle θ is 90 degrees. 
     It is to be noted that the outer edge portion  128  of the second jaw  54  is configured to face the outer edge portion  108  of the first jaw  52 . Therefore, a detailed description of the outer edge portion  128  of the second jaw  54  will be omitted. 
     A function of the treatment system  10  according to this embodiment will now be described. 
     For example, the treatment section  42  is placed to face the biological tissue L as the treatment target. In this state, the opening/closing lever  46   a  of the operating section  46  is operated to hold the biological tissue L between the holding surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64 . 
     As shown in  FIG. 5A , when the biological tissue L as the treatment target and its surrounding tissue S are held by the first and second treatment sections  42   a  and  42   b , the biological tissue L as the treatment target is arranged to be appressed against the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  and also arranged between the grooves  106  and  126 . At this time, when midpoints between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  are collected, a first virtual plane P1 can be defined. That is, the first virtual plane P1 is defined midway between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64 . This virtual plane P1 is a substantially flat plane (including a flat plane) that is substantially parallel (being parallel is included) to the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64 . 
     When the biological tissue is held by the first and second treatment sections  42   a  and  42   b , the surrounding tissue S of the biological tissue L as the treatment target is arranged between the grooves  106  and  126  and the outer edge portions  108  and  128 . At this time, when midpoints between the inclined surfaces  112  and  132  of the outer edge portions  108  and  128  are collected, a second virtual plane P2 can be defined as shown in  FIG. 5B . This surface (the second virtual plane defined midway between the inclined surfaces  112  and  132  of the outer edge portions  108  and  128 ) forms an inclined surface that is inclined with respect to the first virtual plane P1 between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64 . It is to be noted that, in this embodiment, this virtual plane P2 is a substantially flat surface (including a flat surface), and the virtual plane P2 becomes a curved surface if the inclined surfaces  112  and  132  are formed as curved surfaces that are substantially parallel (being parallel is included) to each other. 
     As described above, when the biological tissue is held by the first and second treatment sections  42   a  and  42   b , the biological tissue L as the treatment target is arranged along the virtual plane P1 between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64 . Therefore, when the biological tissue L is held by the first and second treatment sections  42   a  and  42   b , the surrounding tissue S of the biological tissue L as the treatment target is bent at a boundary between virtual plane P1 between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  and the virtual plane P2 between the grooves  106  and  126 . In other words, a shear force that does not lead to cutting is applied to the surrounding tissue S of the biological tissue L as the treatment target, and the surrounding tissue S is bent. 
     That is, the surrounding tissue S of the biological tissue L as the treatment target held between the outer edge portions (the second holding section)  108  and  128  arranged outside the holding surfaces (the first holding section)  62   a  and  64   a  can be bent with respect to the biological tissue L as the treatment target held between the holding surfaces (the first holding section)  62   a  and  64   a  provided on the central side (the inner side) relative to each outer edge of the first and second jaws  52  and  54 . 
     As described above, when the surrounding tissue S is held between the inclined surfaces  112  and  132  of the outer edge portions  108  and  128  while being bent, the contact area relative to the surrounding tissue S can be increased, the surrounding tissue S is held in a state that it is pressed by the inclined surfaces  112  and  132  while applying the shear force that does not result in cutting, and hence the biological tissue hardly slips on the inclined surfaces  112  and  132  even though the biological tissue is pulled, thereby stably holing the surrounding tissue S. 
     It is to be noted that, when the biological tissue is held by the first and second treatment sections  42   a  and  42   b , part of the surrounding tissue S of the biological tissue L as the treatment target enters the grooves  106  and  126 . 
     Therefore, when the biological tissue is held by the first and second treatment sections  42   a  and  42   b , the surrounding tissue S of the biological tissue L as the treatment target is held between the inclined surfaces  112  and  132  of the first and second outer edge portions  108  and  128  in a pressed state. Therefore, a region surrounded by the biological tissue L as the treatment target, the surrounding tissue S, the outer edge portion  108  provided to the first jaw  52 , the groove portion  106 , and the holding surface  62   a  of the energy discharge section  62  is closed. Likewise, a region surrounded by the biological tissue L as the treatment target, the surrounding tissue S, the outer edge portion  128  provided to the second jaw  54 , the groove portion  126 , and the holding surface  64   a  of the energy discharge section  64  is closed. 
     When a state that the pedal  16   a  of the foot switch  16  is pressed down with a foot is maintained in this situation, the control section  22  of the energy source  14  gives energy to the high-frequency electrodes  72  and  74  from the high-frequency energy output circuit  24 . Therefore, the biological tissue L between the surfaces  62   a  and  64   a  of the electrodes  72  and  74  is heated by thermal energy (Joule heat) produced from the high-frequency energy. Further, the biological tissue L is denatured by the thermal energy, and then supply of the energy to the high-frequency electrodes  72  and  74  is stopped. It is to be noted that the control section  22  of the energy source  14  gives the energy to the biological tissue L between the high-frequency electrodes  72  and  74  for the predetermined time t1 and then stops output of the energy from the high-frequency energy output circuit  24 . 
     Here, when the predetermined time t1 has passed from the start of outputting the energy, the energy source  14  stops the supply of the energy to the high-frequency electrodes  72  and  74  even though the pedal  16   a  of the foot switch  16  is being depressed. On the other hand, when a foot is released from the pedal  16   a  before the predetermined time t1 passes, the energy source  14  stops the supply of the energy to the high-frequency electrodes  72  and  74  from the moment of release. 
     As described above, when the biological tissue L as the treatment target between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  is heated, a fluid such as water vapor (a gas) or a biological fluid (a liquid) is produced from the biological tissue L that is in contact with or appressed against the surfaces  62   a  and  64   a . At this time, since the region surrounded by the biological tissue L, the outer edge portion  108 , the groove  106 , and the surface  62   a  of the energy discharge section  62  is formed as a closed space, its inner pressure is raised. Therefore, the fluid flows toward the groove  106  along the surface  62   a  of the energy discharge section  62 , i.e., the surface of the biological tissue L and flows into the groove  106 . Likewise, since the region surrounded by the biological tissue L, the outer edge portion  128 , the groove  126 , and the surface  64   a  of the energy discharge section  64  is formed as a closed space, its inner pressure is raised. Therefore, the fluid flows toward the groove  126  along the surface  64   a  of the energy discharge section  64 , i.e., the surface of the biological tissue L and flows into the groove  126 . 
     As described above, the inner pressure of the region surrounded by the biological tissue L, the outer edge portion  108 , the groove  106 , and the surface  62   a  of the energy discharge section  62  and the inner pressure of the region surrounded by the biological tissue L, the outer edge portion  128 , the groove  126 , and the surface  64   a  of the energy discharge section  64  are raised. Therefore, part of the fluid is to flow from the inner side toward the outer side of the inclined surface  112  and  132  through the inclined surfaces  112  and the  132  of the outer edge portions  108  and  128 . 
     Here, the virtual plane P2 between the inclined surfaces  112  and  132  of the outer edge portions  108  and  128  is not formed as a plane (the same plane) continuous with the virtual plane P1 between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  but as a slant plane. Therefore, as compared with a case where the virtual plane (the slant plane) P2 is flush (the same plane) with the virtual plane (the flat plane) P1, a length (a width W of the slant plane) from the inner side to the outer side of each of the outer edge portions  108  and  128  can be increased. As described, since the length (the width W of the slant plane), i.e., a path from the inner side to the outer side of each of the outer edge portions  108  and  128  can be increased, discharge of the heat from the treatment section  42  to the outside can be more effectively prevented, and spreading of heat from the biological tissue L as the treatment target to its surrounding tissue S can be suppressed, i.e., thermal damage to the surrounding tissue S can be suppressed. Therefore, the fluid can be more effectively prevented from being discharged to the outside of the first and second jaws  52  and  54 , and the fluid can be effectively collected in the grooves  106  and  126 . 
     Furthermore, when the virtual plane P2 is formed as the slant plane as described above, the thickness t of each of the outer edge portions  108  and  128  does not have to be changed. Therefore, a lateral width of each of the jaws  52  and  54  does not have to be increased, and insertability can be excellently maintained at the time of inserting the treatment section  42  to the biological tissue as the treatment target. 
     Moreover, the surrounding tissue S of the biological tissue L as the treatment target that is present on the virtual plane P2 between the inclined surfaces  112  and  132  of the outer edge portions  108  and  128  is bent near a position between the grooves  106  and  126  with respect to the biological tissue L as the treatment target that is present on the virtual plane P1. That is, the surrounding tissue S can be bent near the boundary between the virtual planes P1 and P2 with respect to the biological tissue L as the treatment target. Therefore, the energy is applied to the biological tissue L as the treatment target, the fluid is produced from the biological tissue S as the treatment target, and a flowing direction of the fluid can be changed at a position where the surrounding tissue S is bent with respect to the biological tissue L as the treatment target when the fluid flows along the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64 . As described above, since the surrounding tissue S is bent with respect to the biological tissue L as the treatment target, an intense flow path resistance can be applied to the fluid as compared with a case where the biological tissue L as the treatment target and its surrounding tissue S have flat surfaces that are flush with each other. That is, since the surface along which the fluid flows is bent, the force of flow of the fluid can be weakened as compared with a case where a surface along which the fluid flows is a flat surface. 
     Moreover, although the inner pressure of each of the regions surrounded by the biological tissue, the outer edge portions  108  and  128 , the grooves  106  and  126 , and the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  is increased, the outer edge portions  108  and  128  facing each other stably exercise a holding force (pressing force) for holding the surrounding tissue S. Therefore, heat generated when the biological tissue L as the treatment target is subjected to a treatment can be prevented from being discharged to the outside of the treatment section  42 . 
     It is to be noted that the surrounding tissue S of the biological tissue L as the treatment target which has entered the grooves  106  and  126  is affected by the high-frequency energy at a region closer to the high-frequency electrodes  72  and  74 . Therefore, of the surrounding tissue S that has entered the grooves  106  and  126 , a part that has come into contact with the high-frequency electrodes  72  and  74  is subjected to a treatment together with the biological tissue L as the treatment target. Additionally, the fluid produced from the biological tissue L between the surfaces  62   a  and  64   a  of the electrodes  72  and  74  has a higher temperature than the surrounding tissue S and the fluid moves along the surfaces of the biological tissue L and its surrounding tissue S, the surrounding tissue S that has entered the grooves  106  and  126  is apt to be influenced by the spreading of heat. However, as the surrounding tissue S is firmly held between the end portion  108   a  of the outer edge portion  108  and the end portion  128   b  of the outer edge portion  128 , the inner edge portions  108   a  and  128   b  of the outer edge portions  108  and  128  exercise a function of a barrier section that prevents the fluid from moving to the outside. 
     Further, when the state that the pedal  16   a  of the foot switch  16  is being depressed with a foot is maintained, the output of the energy from the high-frequency energy output circuit  24  is stopped, an appropriate time (a time t3 in  FIG. 3 ) passes (it may be 0 second), and then the energy is output from the heating member drive circuit  26  to heat the heating members  82  and  84  for a time t2. Therefore, heat (thermal energy) of the heating members  82  and  84  is transferred to the electrodes  72  and  74 , and the biological tissue L can be dehydrated. At this time, a fluid is generated from the biological tissue L as the treatment target, and would normally flow toward the outside of the treatment section  42 ; but the fluid flows into the grooves  106  and  126 , and the surrounding tissue S is pressed by the inclined surfaces  112  and  132  of the outer edge portions  108  and  128 , thereby suppressing the thermal spread. 
     As described above, the following can be said. 
     When the biological tissue L as the treatment target and its surrounding tissue S are held by the first and second treatment sections  42   a  and  42   b , the surrounding tissue S between the outer edge portions  108  and  128  can be bent with respect to the biological tissue L between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  and the grooves  106  and  126 . As described above, adopting the configuration in which the surrounding tissue S can be bent with respect to the biological tissue L as the treatment target enables changing a direction along which the fluid discharged from the biological tissue L flows under the influence of the energy discharge sections  62  and  64  from a direction parallel to the virtual plane P1 between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  to a direction parallel to the virtual plane P2 between the inclined surfaces  112  and  132  of the outer edge portions  108  and  128 . Therefore, in the vicinity of the boundary between the plane P1 and the plane P2 in particular, a stronger flow path resistance can be exercised and the force of the fluid discharged from the biological tissue L can be weakened as compared with the case where the plane P1 and the plane P2 are the same flat plane. 
     Further, since the outer edge portions  108  and  128  are formed as the inclined surfaces  112  and  132  that are inclined with respect to the parallel-plane type surfaces (the holding surfaces)  62   a  and  64   a  of the electrodes  72  and  74 , areas of the outer edge portions  108  and  128  can be increased as compared with a case where the outer edge portions  108  and  128  are parallel to the surfaces  62   a  and  64   a  of the electrodes  72  and  74 . Therefore, the length (the width W of each of the inclined surfaces  112  and  132 ) from the inner side to the outer side of each of the outer edge portions  108  and  128  can be increased without changing the width (the thickness t) of each of the outer edge portions  108  and  128 . Therefore, the path from the outer edge of each of the energy discharge sections  62  and  64  to the outer edge (an outer periphery of the treatment section  42 ) of each of the outer edge portions  108  and  128  can be increased without changing the lateral width of each of the first and second jaws  52  and  54 . Therefore, the spreading of heat can be efficiently suppressed without changing the thickness of each of the outer edge portions  108  and  128 . 
     It is preferable for the thicknesses t of the outer edge portions  108  and  128  of the first and second jaws  52  and  54  to be substantially equal to each other, but it is good enough to form the inclined surfaces  112  and  132  of the outer edge portions  108  and  128  of the first and second jaws  52  and  54  to face each other. 
     In this embodiment, although the description has been given as to the first jaw  52  that is the fixed jaw and the second jaw  54  that is the movable jaw, adopting the same configuration for the treatment sections that are movable jaws in the treatment device is preferable. 
     In this embodiment, although the description has been given as to the example where the heating members  82  and  84  are arranged on the back surfaces of the high-frequency electrodes  72  and  74 , the heating members  82  and  84  may not be provided. That is, it is also preferable to perform a series of treatments for the biological tissue by using the high-frequency energy alone. In this case, removing the heating member drive circuit  26  from the energy source  14  shown in  FIG. 2  is also preferable. 
     Furthermore, although the description has been given as to the example using the high-frequency electrodes  72  and  74 , it is also preferable to use the high-frequency electrodes  72  and  74  as heat transfer members that transfer heat generated at the time of heating the heating members  82  and  84  to the biological tissue L in place of using them as members that produce the high-frequency energy. That is, the control section  22  of the energy source  14  shown in  FIG. 2  may drive the heating member drive circuit  26  alone in regard to the series of treatments for the biological tissue L as the treatment target without using the high-frequency energy output circuit  24 . In this case, it is also preferable to remove the high-frequency energy output circuit  24  from the energy source  14  shown in  FIG. 2 . 
     Moreover, in this embodiment, although the description has been given as to a case where the treatment device  12  is a bipolar type treatment device shown in  FIG. 6A , the treatment device  12  may be used as a monopolar type treatment device shown in  FIG. 6B . In the case of  FIG. 6B , a treatment is given in a state that a counter electrode plate R is disposed to a patient P. That is, both the monopolar type and the bipolar type can be adopted for the treatment of the biological tissue L using the high-frequency electrodes  72  and  74 . Additionally, in the case of using the treatment device  12  according to this embodiment as the monopolar type, the high-frequency energy may be given to one of the high-frequency electrodes  72  and  74  alone arranged in the pair of jaws  52  and  54 . It is to be noted that, like the states shown in  FIG. 6A  and  FIG. 6B , using tabular heaters as the heating members  82  and  84  is preferable. That is, arranging the heating members  82  and  84  on the back surfaces of the electrodes  72  and  74  is also preferable. 
     [First Modification of First Embodiment] 
     A first modification of the first embodiment will now be described with reference to  FIG. 7 . It is to be noted that like reference numerals denote the same members or members having the same functions as the members described in the first embodiment as much as possible, and a detailed description thereof will be omitted. 
     This modification is an example in which the energy discharge section  62  (the high-frequency electrode  72  and the heating member  82 ) and the groove  106  are omitted from the first jaw  52 . Therefore, the concave portion  104  is omitted from the first jaw  52 , and the holding surface  62   a  which holds the biological tissue L as the treatment target in cooperation with the holding surface  64   a  of the energy discharge section  64  of the second jaw  54  is formed on the first jaw  52  itself. 
     It is to be noted that, in this modification, the inner end portion  108   a  of the outer edge portion  108  of the first jaw  52  is preferably placed above the holding surface  62   a . Therefore, the inner surface (the end portion  108   a ) of the outer edge portion  108  of the first jaw  52  functions as a barrier section that prevents the fluid from flowing to the outside of the treatment section  42  when the energy is applied to the biological tissue L as the treatment target from the energy discharge section  64 . 
     It is to be noted that, in this embodiment, the high-frequency electrode  74  arranged in the concave portion  124  of the second jaw  54  is of the monopolar type. Therefore, the counter electrode plate R shown in  FIG. 6B  is disposed to a patient and then a treatment is given. 
     A function of the treatment system  10  using the energy according to this embodiment will now be briefly explained. 
     The biological tissue L as the treatment target is arranged between the holding surfaces  62   a  and  64   a  shown in  FIG. 7 , and the surrounding tissue S is arranged between the inclined surfaces  112  and  132  of the outer edge portions  108  and  128 . Therefore, the surrounding tissue S is held in a bent state by the treatment section  42  with respect to the biological tissue L as the treatment target. When the energy is applied to the electrode  74  from the high-frequency energy output circuit  24  in this state, the biological tissue L as the treatment target is denatured, and the fluid is discharged from the biological tissue L. This fluid moves toward the outer edge portions  108  and  128  along the holding surfaces  62   a  and  64   a . At this time, the inner sides of the outer edge portions  108  and  128  function as the barrier sections. Therefore, the fluid flows into the groove  126 . Furthermore, since the surrounding tissue S is held on the inclined surfaces  112  and  132  each having a width larger than the thickness t of each of the outer edge portions  108  and  128 , the spreading of heat can be effectively suppressed. 
     Even when the energy is output from the heating member drive circuit  26  to the heating member  84  after stopping the output to the high-frequency electrode  74  from the high-frequency energy output circuit  24 , the spreading of heat can be likewise effectively suppressed. 
     [Second Modification of First Embodiment] 
     A second modification of the first embodiment will now be described with reference to  FIG. 8 . 
     As shown in  FIG. 8 , this modification is an example in which the first virtual plane P1 between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  is set to be parallel or substantially parallel to the second virtual surface P2 between the outer edge portions  108  and  128  and these planes are shifted in a vertical direction (the opening/closing direction of the jaws  52  and  54 ). In this modification, the outer edge portions  108  and  128  are not formed as the inclined surfaces  112  and  132  shown in  FIG. 4B  but they are formed as surfaces  114  and  134  parallel to the first virtual plane P1. When the first and second virtual planes P1 and P2 are shifted in the vertical direction (the opening/closing direction of the jaws  52  and  54 ) as described above, the surrounding tissue S can be bent with respect to the biological tissue L as the treatment target. 
     As described above, when the configuration that the surrounding tissue S can be bent with respect to the biological tissue L as the treatment target is adopted, a flowing direction of the fluid discharged from the biological tissue L under the influence of the energy discharge sections  62  and  64  can be changed from a direction parallel to the virtual plane P1 between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  to a direction parallel to the virtual plane P2 between the outer edge portions  108  and  128 . Therefore, in the vicinity of the boundary between the plane P1 and the plane P2 in particular, a stronger flow path resistance can be exercised and the force of the fluid discharged from the biological tissue L can be weakened as compared with the case where the plane P1 and the plane P2 are the same flat plane. 
     [Third Modification of First Embodiment] 
     A third modification of the first embodiment will now be described with reference to  FIG. 9 . 
     As shown in  FIG. 9 , this modification is a modification of the second modification, and is an example where the inclined surfaces  112  and  132  are formed on the outer edge portions  108  and  128  as described in the first embodiment. 
     Since the outer edge portions  108  and  128  are formed as the inclined surfaces with respect to the surfaces (the holding surfaces)  62   a  and  64   a  of the electrodes  72  and  74 , areas of the outer edge portions  108  and  128  can be increased as compared with the case where the outer edge portions  108  and  128  are parallel to the surfaces  62   a  and  64   a  of the electrodes  72  and  74 . Therefore, the length from the inner side toward the outer side of each of the outer edge portions  108  and  128  (the width W of each of the inclined surfaces  112  and  132 ) can be increased without changing the width (the thickness t) of each of the outer edge portions  108  and  128 . Therefore, the path from the outer edge of each of the energy discharge sections  62  and  64  to the outer edge of each of the outer edge portions  108  and  128  can be increased without changing the lateral width of each of the first and second jaws  52  and  54 . Therefore, the spreading of heat can be efficiently suppressed without changing the thickness of each of the outer edge portions  108  and  128 . 
     Further, when the configuration that the surrounding tissue S can be bent with respect to the biological tissue L as the treatment target is adopted, like the second modification, the flowing direction of the fluid discharged from the biological tissue L under the influence of the energy discharge sections  62  and  64  can be changed from the direction parallel to the virtual plane P1 between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  to the direction parallel to the virtual plane P2 between the outer edge portions  108  and  128 . Therefore, in the vicinity of the boundary between the plane P1 and the plane P2, a strong flow path resistance can be exercised and the force of the fluid discharged from the biological tissue L can be weakened as compared with the case where the plane P1 and the plane P2 are the same flat plane. 
     [Fourth Modification of First Embodiment] 
     A fourth modification of the first embodiment will now be described with reference to  FIG. 10 . 
     As shown in  FIG. 10 , this modification is an example where the groove  106  is removed from the first jaw  52  according to the third modification. That is, in this modification, although the outer edge portion  108  is present in the first jaw  52 , the first jaw  52  does not have a barrier function. On the other hand, the second jaw  54  has a barrier function for preventing the spreading of heat with the use of the outer edge portion  128 . 
     Since the outer edge portions  108  and  128  are formed as the inclined surfaces  112  and  132  with respect to the surfaces (the holding surfaces)  62   a  and  64   a  of the electrodes  72  and  74 , areas of the outer edge portions  108  and  128  can be increased as compared with a case where the outer edge portions  108  and  128  are parallel to the surfaces  62   a  and  64   a  of the electrodes  72  and  74 . Therefore, the length from the inner side toward the outer side of each of the outer edge portions  108  and  128  (the width W of each of the inclined surfaces  112  and  132 ) can be increased without changing the width (the thickness t) of each of the outer edge portions  108  and  128 . Therefore, the path from the outer edge of each of the energy discharge sections  62  and  64  to the outer edge of each of the outer edge portions  108  and  128  can be increased without changing the lateral width of each of the first and second jaws  52  and  54 . Therefore, the spreading of heat can be efficiently suppressed without changing the thickness of each of the outer edge portions  108  and  128 . 
     Further, when the configuration that the surrounding tissue S can be bent with respect to the biological tissue L as the treatment target is adopted, like the second modification, the flowing direction of the fluid discharged from the biological tissue L under the influence of the energy discharge sections  62  and  64  can be changed from the direction parallel to the virtual plane P1 between the surfaces  62   a  and  64   a  of the energy discharge sections  62  and  64  to the direction parallel to the virtual plane P2 between the outer edge portions  108  and  128 . Therefore, in the vicinity of the boundary between the plane P1 and the plane P2, a strong flow path resistance can be exercised and the force of the fluid discharged from the biological tissue L can be weakened as compared with the case where the plane P1 and the plane P2 are the same flat plane. 
     Furthermore, in this modification, the first jaw  52  can be formed to be relatively small. Accordingly, operability at the time of a treatment performed on the biological tissue, such as insertion of the first jaw  52  between biological tissues, can be improved. 
     [Fifth Modification of First Embodiment] 
     A fifth modification of the first embodiment will now be described with reference to  FIG. 11 . 
     As shown in  FIG. 11 , a lateral width of a lateral cross section of the first jaw  52  is formed to be smaller than a lateral width of a lateral cross section of the second jaw  54 . Therefore, as shown in  FIG. 11 , the outer side of the first outer edge portion  108  of the first jaw  52  can be arranged on the inner side of the second outer edge portion  128  of the second jaw  54 . 
     The inclined surface portion  112  of the first jaw  52  is formed on the outer side of the first outer edge portion  108 , and the inclined surface portion  132  of the second jaw  54  is formed on the inner side of the second outer edge portion  128 . 
     As shown in  FIG. 11 , when the biological tissue is held between the first and second treatment sections  42   a  and  42   b , the biological tissue L as the treatment target is present on the virtual plane P1 formed by collecting midpoints between the surfaces  62   a  and  64   a  of the electrodes  72  and  74 . Further, the surrounding tissue S of the biological tissue L as the treatment target is bent from the grooves  106  and  126  toward the outer edge portions  108  and  128 , and is present on the virtual plane P2 formed by collecting midpoints between the inclined surface portions  112  and  132  by the outer side of the outer edge portion  108  of the first jaw  52  and the inner side of the outer edge portion  128  of the second jaw  54 . A shear force that does not lead to cutting can act on the surrounding tissue S. Therefore, the surrounding tissue S can be bent with respect to the biological tissue L as the treatment target, and the spreading of heat to the surrounding tissue S of the biological tissue L as the treatment target can be effectively suppressed. 
     It is to be noted that, in this modification, the description has been given as to the example where the outer side of the first outer edge portion  108  of the first jaw  52  is arranged on the inner side of the second outer edge portion  128  of the second jaw  54 , but the inner side of the first outer edge portion  108  of the first jaw  52  may be arranged on the outer side of the second outer edge portion  128  of the second jaw  54 . 
     [Sixth Modification of First Embodiment] 
     A sixth modification of the first embodiment will now be described with reference to  FIG. 12 . This modification is a modification of the first embodiment including the foregoing modifications. 
     As shown in  FIG. 12 , cutter guide grooves  116  and  136  are formed in the first and second jaws  52  and  54 , respectively. A cutter  140  can be inserted into or removed from the cutter guide grooves  116  and  136 . The cutter  140  is coupled with a cutter moving lever  46   b  of the operating section  46  shown in  FIG. 1  through a non-illustrated rod. Therefore, when the cutter moving lever  46   b  is operated, the cutter  140  can be guided within a predetermined range along an axial direction of the inserting section  44 . That is, the cutter  140  can be moved between a state that a tip of the cutter  140  is arranged at a position between the first and second jaws  52  and  54  and a state that the tip of the cutter  140  is retracted in the inserting section  44  from the position between the first and second jaws  52  and  54 . Therefore, after giving a treatment by applying the energy to the biological tissue L as the treatment target from the energy discharge sections  62  and  64 , when the cutter moving lever  46   b  is operated to move the tip of the cutter  140  to the distal end side of the first and second jaws  52  and  54  from the proximal end side of the first and second jaws  52  and  54 , the biological tissue L as the treatment target can be cut. 
     Here, as shown in  FIG. 5A  and  FIG. 5B , since the outer edge portions  108  and  128  can hold the surrounding tissue S in a bent state, the surrounding tissue S can be firmly held by the outer edge portions  108  and  128 . Therefore, when the cutter  140  has been moved, it is hard for the surrounding tissue S between the outer edge portions  108  and  128  to slip, and the biological tissue L that has been subjected to a treatment can be assuredly cut. 
     It is to be noted that the cutter guide grooves  116  and  136  have a function of receiving the fluid generated from the biological tissue, like the grooves  106  and  126 . 
     Further, cooling ducts (cooling sections)  142  and  144  are formed in the inclined surfaces  112  and  132  of the outer edge portions  108  and  128 . A cooling medium can be circulated in the cooling ducts  142  and  144 . Therefore, for example, the biological tissue L is held between the holding surfaces  62   a  and  64   a , the surrounding tissue S is held between the inclined surfaces  112  and  132 , the energy is discharged from the energy discharge sections  62  and  64 , and the cooling medium is circulated through the cooling ducts  142  and  144  to cool the surrounding tissue S, whereby the spreading of heat can be further effectively suppressed. 
     It is to be noted that, as shown in  FIG. 12 , the description has been given as to the example where the cooling ducts  142  and  144  are arranged on the outer edges of the inclined surfaces  112  and  132  of the outer edge portions  108  and  128  in this modification, but they may be arranged at centers of the inclined surfaces  112  and  132  of the outer edge portions  108  and  128  in the width direction or on inner edge portions of the same, respectively. Moreover, the cooling ducts  142  and  144  do not have to be formed when the energy discharge section is not provided on the holding surface  62   a , like the first modification (see  FIG. 7 ). 
     Additionally, all the surrounding tissue S pressed by the inclined surfaces  112  and  132  may be cooled by arranging plates having excellent thermal conductivity on the inclined surfaces  112  and  132 , and the heat of the cooling ducts  142  and  144  is therefore transferred to the plates. 
     Since other structures or functions are the same as the structures and the functions described in the first embodiment, a description thereof will be omitted here. 
     Second Embodiment 
     A second embodiment will now be described with reference to  FIG. 13  to  FIG. 15A . This embodiment is a modification of the first embodiment including the respective modifications, and like reference numerals denote the same members or members having the same functions as the members described in the first embodiment as much as possible to omit a repeated description. 
     Here, as an energy treatment device, a description will be given as to an example of a circular type surgical device (the energy treatment device)  212  used for giving a treatment through an abdominal wall or outside the abdominal wall. In this embodiment, although a bipolar type surgical device  212  will be described, the treatment device may be formed as a monopolar type energy treatment device by using a counter electrode plate R shown in  FIG. 6B . 
     As shown in  FIG. 13 , a treatment system  10  using energy has a treatment device (the energy treatment device)  212 , an energy source  14  that gives energy to the treatment device  212 , and a foot switch  16 . 
     The surgical device  212  includes a handle (an operating section)  222 , a shaft (an inserting section)  224 , and an openable/closable treatment section  226 . The energy source  14  is connected to the handle  222  through a cable  18   a.    
     A holding section opening/closing knob  232  and a cutter driving lever  234  are arranged on the handle  222 . The holding section opening/closing knob  232  is rotatable with respect to the handle  222 . A later-described separation side treatment section (a separation side grip section)  244  of the treatment section  226  is separated from a main body side treatment section (a main body side grip section)  242  when this holding section opening/closing knob  232  is rotated in, e.g., a clockwise direction with respect to the handle  222  (see  FIG. 14A ), and the separation side treatment section  244  moves closer to the main body side treatment section  242  when the holding section opening/closing knob  232  is rotated in a counterclockwise direction (see  FIG. 14B ). 
     As shown in  FIG. 13 , the shaft  224  is formed into a cylindrical shape. This shaft  224  is appropriately curved in consideration of insertability into a biological tissue L. Forming the shaft  224  straight is also preferable. 
     The treatment section  226  is arranged at a distal end of the shaft  224 . As shown in  FIG. 14A  and  FIG. 14B , the treatment section  226  includes a main body side treatment section (a first holding member, a first jaw)  242  formed at the distal end of the shaft  224  and a separation side treatment section (a second holding member, a second jaw)  244  that can be attached to or detached from this main body side treatment section  242 . In a state that the separation side treatment section  244  is closed with respect to the main body side treatment section  242 , outer edge portions  242   a  and  244   a  of the main body side treatment section  242  and the separation side treatment section  244  move closer to each other in an opposed state or abut on each other. Therefore, the circular outer edge portion  242   a  faces the circular outer edge portion  244   a  and forms a holding section (the second holding section) that holds a surrounding tissue S of a biological tissue L as a treatment target. 
     As shown in  FIG. 15A , in this embodiment, the outer edge portions  242   a  and  244   a  are inclined with respect to a central axis C (see  FIG. 14A  and  FIG. 14B ) of the main body side treatment section  242  and the separation side treatment section  244  and a direction orthogonal to the central axis C. 
     The outer edge portion  242   a  itself of the main body side treatment section  242  has an end portion (the uppermost end)  243   a  on an inner side thereof (a side close to a high-frequency electrode  272 ) provided above an end portion  243   b  on an outer side thereof (a side apart from the first high-frequency electrode  272 ) in this embodiment, and the end portion  243   a  on the inner side is smoothly continuous with the end portion  243   b  on the outer side. Therefore, an inclined surface  242   b  is formed on the outer edge portion  242   a.    
     The outer edge portion  244   a  itself of the separation side treatment section  244  has an end portion (the uppermost end)  245   a  on an inner side thereof (a side close to a second high-frequency electrode  286 ) provided above an end portion  245   b  on an outer side thereof (a side apart from the second high-frequency electrode  286 ) in this embodiment, and the inner end portion  245   a  is smoothly continuous with the outer end portion  245   b . Therefore, an inclined surface  244   b  is formed on the outer edge portion  244   a.    
     As shown in  FIG. 14A  and  FIG. 14B , the main body side treatment section  242  includes a cylindrical body  252 , a frame  254 , and an energization pipe  256 . The cylindrical body  252  and the frame  254  have electrical insulation properties. The cylindrical body  252  is coupled with the distal end of the shaft  224 . The frame  254  is arranged while being fixed to the cylindrical body  252 . 
     The frame  254  has opening in a central axis thereof. The energization pipe  256  is arranged in the opened central axis C of this frame  254  so that it can move within a predetermined range along the central axis C of the frame  254 . As shown in  FIG. 14A  and  FIG. 14B , when the holding section opening/closing knob  232  is rotated, this energization pipe  256  can move within the predetermined range by a function of, e.g., a ball screw (not shown). A protrusion  256   a  that projects inward along a radial direction is formed on this energization pipe  256  so that a later-described connecting portion  282   a  of the energization shaft  282  in the separation side treatment section  244  can be engaged or disengaged. 
     As shown in  FIG. 14A  to  FIG. 14C , a cutter guide groove (a space)  266  is formed between the cylindrical body  252  and the frame  254 . A cylindrical cutter  262  is arranged in the cutter guide groove  266 . A proximal end portion of this cutter  262  is connected to a distal end portion of a cutter pusher  264  arranged on the inner side of the shaft  224 . The cutter  262  is fixed on an outer peripheral surface of the cutter pusher  264 . Although not shown, a proximal end portion of the cutter pusher  264  is connected to the cutter driving lever  264  of the handle  222 . Therefore, when the cutter driving lever  234  of the handle  222  is operated, the cutter  262  moves through the cutter pusher  264 . 
     A first fluid ventilation path (a fluid path)  268   a  is formed between the cutter pusher  264  and the frame  254 . Further, a fluid discharge opening (not shown) from which the fluid flowing through the first fluid ventilation path  268   a  is discharged to the outside is formed in the shaft  224  or the handle  222 . 
     As shown in  FIG. 14A  and  FIG. 14B , as output members or energy discharge sections, the first high-frequency electrode  272  and heating members  274  are arranged at a distal end of the cylindrical body  252 . 
     The first high-frequency electrode  272  is arranged on an outer side of the cutter guide groove  266  having the cutter  262  arranged therein. The first high-frequency electrode  272  is formed into a circular shape like the cutter guide groove  266 . A distal end of a first energization line  272   a  is fixed to the first high-frequency electrode  272 . The first energization line  272   a  is connected to a cable  18   a  through the main body side treatment section  242 , the shaft  224 , and the handle  222 . 
     As shown in  FIG. 14A  to  FIG. 14C , the heating members  274  are fixed on a back surface of the first high-frequency electrode  272  at appropriate intervals. A tip of a heater energization line  274   a  is fixed to each heating member  274 . The heater energization line  274   a  is connected to the cable  18   a  through the main body side treatment section  242 , the shaft  224 , and the handle  222 . 
     It is to be noted that using one or more tabular heaters as the heating members  274  is also preferable. 
     A fluid discharge groove  276  is annularly formed on the outer side of the first high-frequency electrode  272 . The fluid discharge groove  276  is formed to communicate with the first fluid ventilation path  268   a . The inclined surface (a tissue contact surface)  242   b  of the outer edge portion  242   a  is formed on the outer side of the fluid discharge groove  276  at a position protruding from the surface of the first high-frequency electrode  272 . That is, the inclined surface  242   b  of the outer edge portion  242   a  of the main body side treatment section  242  is closer to a later-described head section  284  of the separation side treatment section  244  than the surface of the first high-frequency electrode  272 . Therefore, the end portion (the uppermost end)  243   a  on the inner side of the outer edge portion  242   a  (the side close to the first high-frequency electrode  272 ) functions as a barrier section (a dam) that prevents a fluid such as vapor from escaping to the outer side of the fluid discharge groove  276 . 
     On the other hand, the separation side treatment section  244  includes an energization shaft  282  having the connecting portion  282   a  and the head section  284 . The energization shaft  282  has a circular cross section, one end formed into a tapered shape, and the other end fixed to the head section  284 . The connecting portion  282   a  is formed into a concave groove shape that can be engaged with the protrusion  256   a  of the energization pipe  256 . An outer surface of the energization shaft  282  except for the connecting portion  282   a  is insulated by a coating or the like. 
     The second high-frequency electrode  286  is arranged in the head section  284  to face the first high-frequency electrode  272  of the main body side treatment section  242 . One end of a second energization line  286   a  is fixed to the second high-frequency electrode  286 . The other end of the second energization line  286   a  is electrically connected to the energization shaft  282 . 
     The high-frequency electrodes  272  and  286  face each other and are used as holding surfaces (a first holding section)  273  and  286  for the biological tissue L as the treatment target. Therefore, when high-frequency energy is given to the electrodes  272  and  286  in a state that the biological tissue L is held between the holding surfaces  273  and  287  of the electrodes  272  and  286 , the biological tissue L can be denatured by thermal energy that has heated the biological tissue. Further, the electrode  272  is made of a material having excellent thermal conductivity. Therefore, when the heating member  274  is heated, the heat (thermal energy) is transferred to the electrode  272 , and the heat (the thermal energy) can be further transferred to the biological tissue L that is in contact with the holding surface  273  of the electrode  272 . Therefore, the holding surfaces  273  and  287  also function as treatment surfaces for the biological tissue L. It is to be noted that the heating members are not arranged on the back surface of the electrode  286  in this embodiment, but the electrode  286  may be made of a material having excellent thermal conductivity, the heating members may be arranged on the back surface of the electrode  286 , and the heat generated by the heating members may be transferred to the electrode  286 . 
     A cutter receiving portion  288  is annularly formed on the inner side of the second high-frequency electrode  286  arranged in the head section  284  so that a blade at a tip of the cutter  262  can be received. On the other hand, a fluid discharge groove  290  is annularly formed on the outer side of the second high-frequency electrode  286 . On the outer side of the fluid discharge groove  290 , an inclined surface (a tissue contact surface)  244   b  of the outer edge portion  244   a  is formed at a position protruding from the surface of the second high-frequency electrode  286 . That is, the outer edge portion  244   a  of the separation side treatment section  244  is arranged to be closer to the main body side treatment section  242  than the surface of the second high-frequency electrode  286 . Therefore, the end portion  245   a  on the inner side (the side close to the second high-frequency electrode  286 ) of the outer edge portion  244   a  functions as a barrier section (a dam) that prevents a fluid such as vapor from escaping to the outside from the fluid discharge groove  290 . 
     Furthermore, the fluid discharge groove  290  is configured to communicate with a fluid discharge path  290   a  of the head section  284  and the energization shaft  282 . The fluid discharge path  290   a  communicates with a second fluid ventilation path (a fluid path)  268   b  of the energization pipe  256 . A fluid discharge opening (not shown) from which the fluid flowing through the second fluid ventilation path  268   b  is discharged to the outside is formed in the shaft  204  or the handle  202 . 
     It is to be noted that the energization pipe  256  is connected to the cable  18   a  through the shaft  224  and the handle  222 . Therefore, when the connecting portion  282   a  of the energization shaft  282  in the separation side treatment section  244  is engaged with the protrusion  256   a  of the energization pipe  256 , the second high-frequency electrode  286  is electrically connected to the energization pipe  256 . 
     A function of the therapeutic treatment system  10  according to this embodiment will now be described. 
     An operator operates the display section  28  (see  FIG. 2  and  FIG. 13 ) of the energy source  14  in advance to set output conditions of the therapeutic treatment system  10 . Specifically, set power Pset [W] of a high-frequency energy output, a set temperature Tset [° C.] of a thermal energy output, threshold values Z1 and Z2 of impedance Z of the biological tissue L, and so on are set in advance. 
     As shown in  FIG. 14B , in a state that the main body side treatment section  242  is closed with respect to the separation side treatment section  244 , the treatment section  226  and the shaft  224  of the surgical treatment device  212  are inserted into, e.g., an abdominal cavity through an abdominal wall. The main body side treatment section  242  and the separation side treatment section  244  of the surgical treatment device  212  are arranged to face a biological tissue as a treatment target. 
     To grip the biological tissue as the treatment target with the use of the main body side treatment section  242  and the separation side treatment section  244 , the grip section opening/closing knob  232  of the handle  222  is operated. At this time, the knob  232  is turned in, e.g., the clockwise direction with respect to the handle  222 . Then, as shown in  FIG. 14A , the energization pipe  256  is moved to the distal end portion side with respect to the frame  254  of the shaft  224 . Therefore, a space is formed between the main body side treatment section  242  and the separation side treatment section  244 , and the separation side treatment section  244  can be separated from the main body side treatment section  242 . 
     Additionally, the biological tissue L to be subjected to a treatment is arranged between the first high-frequency electrode  272  of the main body side treatment section  242  and the second high-frequency electrode  286  of the separation side treatment section  244 . The energization shaft  282  of the separation side treatment section  244  is inserted into the energization pipe  256  of the main body side treatment section  242 . In this state, the grip section opening/closing knob  232  of the handle  222  is turned in, e.g., the counterclockwise direction. Therefore, the separation side treatment section  244  is closed with respect to the main body side treatment section  242 . In this manner, the biological tissue L as the treatment target is held between the main body side treatment section  242  and the separation side treatment section  244 . 
     When the biological tissue is held between the holding surfaces  273  and  287  of the electrodes  272  and  286  and between the inclined surfaces  242   b  and  244   b  of the outer edge portions  242   b  and  244   a , a virtual plane formed by collecting midpoints between the holding surfaces  273  and  287  of the electrodes  272  and  286  crosses a virtual plane formed by collecting midpoints between the inclined surfaces  242   b  and  244   b  of the outer edge portions  242   a  and  244   a . Therefore, the biological tissue between the outer edge portions  242   a  and  244   a  (a surrounding tissue of the biological tissue as the treatment target) can be held while being bent with respect to the biological tissue between the holding surfaces  273  and  287  of the electrodes  272  and  286  (the biological tissue as the treatment target). 
     As compared with a case where an angle of each of the outer edge portions  242   a  and  244   a  is orthogonal to the central axis C, a width of each of the inclined surfaces  242   b  and  244   b  of the outer edge portions  242   a  and  244   a  according to this embodiment is increased in accordance with the angle. Therefore, when the inclined surfaces  242   b  and  244   b  are formed on the outer edge portions  242   a  and  244   a , a contact area of the biological tissue as the treatment target with respect to the surrounding tissue can be increased as compared with a case where an angle of each of the inclined surfaces  242   b  and  244   b  of the outer edge portions  242   a  and  244   a  is orthogonal to the central axis C. 
     In this state, a pedal  216   a  of a foot switch  216  is operated, and energy is supplied to the first high-frequency electrode  272  and the second high-frequency electrode  286  from the energy source  14  through the cable  18   a , respectively. Therefore, the biological tissue L between the first high-frequency electrode  272  of the main body side treatment section  242  and the second high-frequency electrode  286  of the separation side treatment section  244  is heated by Joule heat. 
     As the biological tissue is heated, a fluid (a liquid (blood) and/or a gas (water vapor)) is discharged from the biological tissue. At this time, the fluid discharged from the biological tissue L is allowed to flow into the cutter guide groove  266  and the fluid discharge groove  276  of the main body side treatment section  242 , and also into the fluid discharge groove  290  of the separation side treatment section  244 . Further, for example, the fluid that has flowed into the cutter guide groove  266  and the fluid discharge groove  276  of the main body side treatment section  242  is sucked into the shaft  224  from the cutter guide groove  266  through the first fluid ventilation path  268   a . Furthermore, for example, the fluid that has flowed into the fluid discharge groove  290  of the separation side treatment section  244  is sucked into the shaft  224  from the fluid discharge path  290   a  of the head section  284  and the energization shaft  282  through the second fluid ventilation path  268   b  of the energization pipe  256 . 
     Moreover, the inflow of the fluid is continued while the fluid is being discharged from the biological tissue L. Therefore, the fluid discharged from the biological tissue L in a state that a temperature is raised can be prevented from spreading heat and also prevented from affecting a part that is not a treatment target. 
     Additionally, since the surrounding tissue is bent with respect to the biological tissue as the treatment target, a strong flow path resistance can be exercised, and the force of the fluid discharged from the biological tissue L can be weakened. Further, as regards areas of the inclined surfaces  242   b  and  244   b  of the outer edge portions  242   a  and  244   a , since the inclined surfaces  242   b  and  244   b  are formed to be inclined with respect to the plane orthogonal to the central axis C, contact areas relative to the surrounding tissue can be increased as compared with a case where the inclined surfaces  242   b  and  244   b  are formed as planes orthogonal to the central axis C. Furthermore, when a shear force that does not lead to cutting is enabled to act on the surrounding tissue S, the surrounding tissue can be further assuredly held. Therefore, the spreading of heat relative to the surrounding tissue of the biological tissue as the treatment target can be effectively suppressed. 
     When the impedance Z has been determined to be higher than the threshold value Z1, a signal is transmitted from the control section  22  to a heating element drive circuit  26 . Moreover, the heating element drive circuit  26  supplies electric power to the heating members  274  in such a manner that a temperature of the heating members  274  becomes the preset temperature Tset [° C.], e.g., 100[° C.] to 300[° C.]. Therefore, as to the biological tissue gripped between the electrodes  272  and  286  of the main body side treatment section  242  and the separation side treatment section  244 , heat is transferred to the first high-frequency electrode  272  by heat conduction from the heating members  274 , and the biological tissue is coagulated by this heat from the surface side toward the inside of the biological tissue appressed against the first high-frequency electrode  272 . 
     Then, the control section  22  determines whether the impedance Z of the biological tissue monitored by the high-frequency energy output circuit  24  has become greater than or equal to the preset threshold value Z2. When the impedance Z has been determined to be smaller than the threshold value Z2, supply of the energy to the heating members  274  is continued. On the other hand, when the impedance Z has been determined to be greater than or equal to the threshold value Z2, the control section  22  generates a buzzer from a speaker  30  and stops output of the high-frequency energy and the thermal energy. Therefore, the treatment for the biological tissue using the therapeutic treatment system  10  is terminated. 
     As described above, the biological tissue is continuously denatured (in a substantially annular state) by the first and second high-frequency electrodes  272  and  286  and the heating member  274 . 
     Moreover, when the cutter driving lever  234  of the handle  222  is operated, the cutter  262  projects from the cutter guide groove  266  of the main body side treatment section  242  and moves toward the cutter receiving portion  288  in the separation side treatment section  244 . Since the blade of the cutter  262  is at the tip thereof, the biological tissue subjected to the treatment is cut into an arc shape, a circular shape, or the like. 
     At this time, since the surrounding tissue is firmly held by the inclined surfaces  242   b  and  244   b , it is hard for the surrounding tissue between the inclined surfaces  242   b  and  244   b  to slip with respect to the inclined surfaces  242   b  and  244   b , and the biological tissue can be easily cut by the cutter  262 . 
     As described above, according to this embodiment, the following effect can be provided. 
     The first high-frequency electrode  272  and the heating members  274  can be annularly arranged in the main body side treatment section  242  and the second high-frequency electrode  286  can be annularly arranged in the separation side treatment section  244  to give a treatment. Therefore, the biological tissue L between the main body side treatment section  242  and the separation side treatment section  244  can be substantially annularly treated. 
     When the biological tissue is held between the holding surfaces  273  and  287  of the electrodes  272  and  286  and between the inclined surfaces  242   b  and  244   b  of the outer edge portions  242   a  and  244   a , the virtual plane formed by collecting midpoints between the holding surfaces  273  and  287  of the electrodes  272  and  286  crosses the virtual plane formed by collecting midpoints between the inclined surfaces  242   b  and  244   b  of the outer edge portions  242   a  and  244   a . Therefore, the biological tissue between the inclined surfaces  242   b  and  244   b  of the outer edge portions  242   a  and  244   a  (the surrounding tissue of the biological tissue as the treatment target) can be held in a bent state with respect to the biological tissue between the holding surfaces  273  and  287  of the electrodes  272  and  286  (the biological tissue as the treatment target). As described above, when the biological tissue is held in such a manner that its surrounding tissue is bent with respect to the biological tissue as the treatment target, a strong flow path resistance can be exercised near a boundary between the biological tissue as the treatment target and the surrounding tissue with respect to the fluid discharged from the biological tissue, and the force of the fluid discharged from the biological tissue L can be weakened. 
     The width of the outer edge portion  242   a  according to this embodiment is increased in accordance with the angle of the inclined surface  242   b  of the outer edge portion  242   a  as compared with the case where the angle is orthogonal to the central axis C. Therefore, if the inclined surface  242   b  is formed on the outer edge portion  242   a , the contact area of the biological tissue as the treatment target with respect to the surrounding tissue can be increased as compared with a case where the angle of the inclined surface  244   b  of the outer edge portion  242   a  is orthogonal to the central axis C. Therefore, the spreading of heat of the biological tissue as the treatment target relative to the surrounding tissue can be effectively suppressed. 
     Further, in the second embodiment, although the description has been given as to the case where the high-frequency energy is provided by the electrodes  272  and  286  and the thermal energy is provided by the heating members  274 , the high-frequency energy provided by the electrodes  272  and  286  or the thermal energy provided by the heating members  274  alone may be used as the energy. 
     [First Modification of Second Embodiment] 
     A first modification of the second embodiment will now be described with reference to  FIG. 15B . It is to be noted that like reference numerals denote the same members or members having the same functions as the members described in the second embodiment as much as possible to omit a detailed description thereof. 
     As shown in  FIG. 15B , this modification is an example in which inclining directions of the inclined surfaces  242   b  and  244   b  of the outer edge portions  242   a  and  244   a  are changed with respect to the second embodiment (see  FIG. 15A ). 
     In this modification, the outer edge portion  242   a  itself has the end portion (the lowermost end)  243   a  on the inner side thereof (the side close to the first high-frequency electrode  272 ) provided below the end portion  243   b  on the outer side thereof (the side apart from the first high-frequency electrode  272 ), and the end portion  243   a  on the inner side is smoothly continuous with the end portion  243   b  on the outer side. Therefore, the inclined surface  242   b  is formed on the outer edge portion  242   a.    
     In this modification, the outer edge portion  244   a  itself has the end portion (the lowermost end)  245   a  on the inner side thereof (the side close to the second high-frequency electrode  286 ) provided below the end portion  245   b  on the outer side thereof (the side apart from the second high-frequency electrode  286 ), and the end portion  245   a  on the inner side is smoothly continuous with the end portion  245   b  on the outer side. Therefore, the inclined surface  244   b  is formed on the outer edge portion  244   a.    
     As described in the second embodiment, when the biological tissue is held between the holding surfaces  273  and  287  of the electrodes  272  and  286  and between the inclined surfaces  242   b  and  244   b  of the outer edge portions  242   a  and  244   a , the biological tissue between the inclined surfaces  272   b  and  244   b  of the outer edge portions  242   a  and  244   a  (the surrounding tissue of the biological tissue as the treatment target) can be held in a bent state with respect to the biological tissue between the holding surfaces  273  and  287  of the electrodes  272  and  286  (the biological tissue as the treatment target). Furthermore, the contact area of the surrounding tissue can be increased as compared with the case of forming flat surfaces orthogonal to the central axis C. 
     [Second Modification of Second Embodiment] 
     A second modification of the second embodiment will now be described with reference to  FIG. 15C . 
     As shown in  FIG. 15C , this modification is an example where the virtual plane formed by collecting midpoints between the holding surfaces  273  and  287  of the electrodes  272  and  286  is parallel to the virtual plane formed by collecting midpoints between the flat surfaces  242   c  and  244   c  of the outer edge portions  242   a  and  244   a , but these planes are arranged at different positions. 
     Although flat surfaces  242   c  and  244   c  parallel to the direction orthogonal to the central axis C (see  FIG. 14A  and  FIG. 14B ) of the main body side treatment section  242  and the separation side treatment section  244  are formed on the outer edge portions  242   a  and  244   a . Positions of the midpoints between the flat surfaces  242   c  and  244   c  of the outer edge portions  242   a  and  244   a  are positions closer to the lower end of the fluid discharge groove  276  than the midpoints between the holding surfaces  273  and  287  of the electrodes  272  and  286 . 
     Therefore, when the biological tissue is held between the holding surfaces  273  and  287  of the electrodes  272  and  286  and between the flat surfaces  242   c  and  244   c  of the outer edge portions  242   a  and  244   a , the biological tissue between the flat surfaces  242   c  and  244   c  of the outer edge portions  242   a  and  244   a  can be held in a bent state with respect to the biological tissue between the holding surfaces  273  and  287  of the electrodes  272  and  286 . Furthermore, since a length from the virtual plane formed by collecting the midpoints between the holding surfaces  273  and  287  of the electrodes  272  and  286  to the virtual plane formed by collecting the midpoints between the flat surfaces  242   c  and  244   c  of the outer edge portions  242   a  and  244   a  can be increased, the force of the fluid discharged from the biological tissue L can be weakened, and occurrence of the spreading of heat relative to the surrounding tissue can be suppressed. 
     [Third Modification of Second Embodiment] 
     A third modification of the second embodiment will now be described with reference to  FIG. 15D . 
     As shown in  FIG. 15D , this modification is an example in which positions of the outer edge portions  242   a  and  244   a  are changed with respect to the second modification (see  FIG. 15C ). 
     The outer edge portions  242   a  and  244   a  are formed parallel to the direction orthogonal to the central, axis C (see  FIG. 14A  and  FIG. 14B ) of the main body side treatment section  242  and the separation side treatment section  244 . Moreover, positions of the midpoints between the flat surfaces  242   c  and  244   c  of the outer edge portions  242   a  and  244   a  are positions closer to the upper end of the fluid discharge groove  290  than the midpoints between the holding surfaces  273  and  287  of the electrodes  272  and  286 . 
     Therefore, when the biological tissue is held between the holding surfaces  273  and  287  of the electrodes  272  and  286  and between the flat surfaces  242   c  and  244   c  of the outer edge portions  242   a  and  244   a , the biological tissue between the flat surfaces  242   c  and  244   c  can be held in a bent state with respect to the biological tissue between the holding surfaces  273  and  287  of the electrodes  272  and  286 . 
     [Fourth Modification of Second Embodiment] 
     A fourth modification of the second embodiment will now be described with reference to  FIG. 15E . 
     As shown in  FIG. 15E , this modification is an example where the first outer edge portion  242   a  is arranged on the inner side of the second outer edge portion  244   a  and the biological tissue is bent between the outer edge portions  242   a  and  244   a.    
     The outer edge portion  242   a  of the main body side treatment section  242  has an inner holding surface  246   a , an outer holding surface  246   b , and a coupling surface  246   c . The coupling surface  246   c  is formed to couple the inner holding surface  246   a  with the outer holding surface  246   b . The inner holding surface  246   a  and the outer holding surface  246   b  are formed to be substantially parallel to each other. The outer edge portion  244   a  of the separation side treatment section  244  has an inner holding surface  247   a , an outer holding surface  247   b , and a coupling surface  247   c . The coupling surface  247   c  is formed to couple the inner holding surface  247   a  with the outer holding surface  247   b . The inner holding surface  247   a  and the outer holding surface  247   b  are formed to be substantially parallel to each other. Further, the coupling surfaces  246   c  and  247   c  are formed as, e.g., surfaces substantially parallel to the central axis C. 
     Therefore, when the biological tissue is held between the holding surfaces  273  and  287  of the electrodes  272  and  286  and between the outer edge portions  242   a  and  244   a , the biological tissue between the outer edge portions  242   a  and  244   a  can be held in a bent state with respect to the biological tissue between the holding surfaces  273  and  287  of the electrodes  272  and  286 . At this time, since a shear force that does not lead to cutting can act on the surrounding tissue S, the surrounding tissue can be further firmly held. 
     It is to be noted that one of the holding surfaces  273  and  287  may be used as an energy discharge section and the other of the same may be configured not to discharge energy, like the first modification of the first embodiment (see  FIG. 7 ). 
     In this embodiment, likewise, bending the surrounding tissue with respect to the biological tissue as the treatment target enables increasing a length from the biological tissue as the treatment target to the outer edge of each of the treatment sections  242  and  244 . Therefore, a direction of the surrounding tissue can be changed, and a contact area of each of the outer edge portions  242   a  and  244   a  can be increased. Therefore, occurrence of the spreading of heat relative to the surrounding tissue can be effectively suppressed. 
     It is to be noted that, in this embodiment, changing the length of each of the treatment sections  242  and  244  to the central axis C like the fifth modification of the first embodiment (see  FIG. 11 ), i.e., forming the outer edge portions  242   a  and  244   a  with different outer diameters enables bending the surrounding tissue. Either the outer edge portion  242   a  or  244   a  may be formed with an increased outer diameter. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.