Patent Publication Number: US-2012035606-A1

Title: Body Tissue Incision Apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a divisional application of U.S. Ser. No. 12/136,388, entitled “Body Tissue Incision Apparatus”, filed Jun. 10, 2008. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable. 
     BACKGROUND OF INVENTION 
     The present invention relates to an endoscopic instrument used to harvest body tissue such as a saphenous vein or other blood vessels for use in surgery to graft a harvested vessel into another site within a body, such as in a coronary bypass. 
     An instrument used to harvest blood vessels is known from Japanese Unexamined Patent Application Publication 2006-000485 (which is priority for U.S. patent application publication 2006/0206112A1). This conventional body tissue harvesting instrument is used in order to dissect veins from surrounding tissue and then to sever and remove the veins from inside the human body. 
     For example, in coronary bypass operations on blood vessels surrounding the heart, after the diseased (i.e., occluded) part of the blood vessels is identified, a portion of vein harvested from the patient&#39;s leg is used to create an alternate pathway for blood to perfuse the artery distally of the diseased vessel, thus making a bypass. When harvesting veins from a leg of the human body, it is frequently the case that a portion of the saphenous vein extending along the leg between the groin and the ankle is harvested. 
     The work of harvesting this portion of vein is conducted as follows. First, with the patient under general anesthesia, a skin incision followed by blunt dissection at the incision site is performed in the knee area of the leg. Next, a trocar is set in this opening and an elongated dissector (which is a blood-vessel dissecting instrument for separating the vessel from surrounding tissue) is inserted into the leg via the trocar. The insertion part of an endoscope is removably attached to the dissector, which is also provided with a channel for a fluid such as, for example, carbon dioxide gas. Under observation by this endoscope inserted near the knee, and sequentially working along the saphenous vein in two opposite directions (i.e., from the knee to the groin and then from the knee to the ankle), the aforementioned desired portion of the vein is separated and isolated from its surrounding tissue together with multiple small venous branches from the aforementioned desired vein portion. During this time, the aforementioned CO 2  fluid is emitted from the tip of the dissector, creating a cavity around the tip of the dissector inside the leg, thereby facilitating observation of the tip of the dissector by the endoscope. 
     Next, the dissector is removed from the leg interior, and in its place the surgeon or medical technician inserts an insertion member of a blood-vessel harvesting apparatus into the leg via the trocar. The insertion part of an endoscope is removably attached to the insertion member of the harvester, which is also provided with a channel for a fluid such as, for example, carbon dioxide gas. A blood-vessel holder is retractably provided at the tip of this insertion member, which is also provided with a retractable blood-vessel cutter. Operations including forward and backward movement of the blood-vessel holder at the aforementioned tip are made feasible by a blood-vessel holder manipulation member on a handle provided at the proximal end of the insertion member and which is exposed to outside space from the trocar. Operations including forward and backward movement of the blood-vessel cutter at the aforementioned tip are made feasible by a blood-vessel cutter manipulation member on the handle provided at the proximal end of the insertion member and which is exposed to outside space from the trocar. 
     While observing the aforementioned desired portion of vein via the endoscope, the blood-vessel holder manipulation member and/or the insertion member is manipulated by the surgeon or technician, and the aforementioned desired portion of vein is held by the blood-vessel holder. Furthermore, by manipulating at least one of blood-vessel holder manipulation member, insertion member, and blood-vessel cutter manipulation member, the aforementioned multiple small venous branches protruding from the desired portion of vein are sequentially cut by sequential use of the blood-vessel cutter, working from the knee to the groin and then from the knee to the ankle. The blood-vessel cutter is configured so as to simultaneously cut and cauterize blood vessels by means of application of a high-frequency current to generate extreme heat in a very localized area. During this time, the aforementioned fluid is emitted from the tip of the insertion member, creating a cavity around the tip of the insertion member inside the leg, and thereby facilitating observation of the tip of the insertion member by the endoscope. 
     When cutting of all of the aforementioned multiple small venous branches from the aforementioned desired portion of vein is completed, incisions are made at the surface of the leg in the respective regions of the groin and the ankle corresponding to the two ends of the aforementioned desired portion of vein in order to expose the two ends of the aforementioned desired portion of vein. Next, the two exposed ends of the aforementioned desired portion of vein are ligated, after which the two ends of the aforementioned desired portion of vein are cut on the inner side of the ligature position. The incisions in the groin and the ankle are then closed with, for example, adhesive plaster or the like. The aforementioned desired portion of vein whose two ends have been cut is extracted from the central opening in the knee, and this opening is finally closed with, for example, suturing adhesive plaster or the like. 
     The desired portion of vein harvested in this manner undergoes a check for the existence of perforations or lesions in the vascular wall, after which the portions free of perforations and lesions in the vascular wall are used in the aforementioned bypass operation. 
     The blood-vessel cutter of the conventional elongate body tissue harvesting instrument disclosed by Japanese Unexamined Patent Application Publication 2006-000485 contains a cutter which possesses a slit whose tip opens in a V-shape, with two electrodes disposed along the two side edges of the slit at the base end of the slit and the outer surface of the cutter. Here, the blood vessels captured in the tip of the slit which is opened in a V-shape are flattened by the slit while being moved to the base end of the slit, and in this state are burnt through by the high-frequency current which flows between the aforementioned two electrodes, whereby the cut portion is clotted (i.e., cauterized). 
     With respect to body tissue harvesting instruments for use in narrow places inside the body, there is constant demand for the ability to conduct more precise harvesting of body tissue in a shorter time, and with simpler operations. 
     SUMMARY OF INVENTION 
     The body tissue harvesting instrument according to one aspect of the present invention is provided with an insertion member which has a tip and a proximal end part wherein the tip is inserted first into the body and a cutter which is provided at the tip of the insertion member and which severs tissue inside the body. Furthermore, the cutter includes a cutter body having a proximal end part held at the tip of the insertion member, a projection which projects from the tip of the insertion member, and a slit which extends from the projection toward the proximal end part. A first high-frequency electrode is disposed along the two side edges of the slit on the outer surface of the cutter body. A second high-frequency electrode is disposed at the base end of the slit in the cutter body. A feeding mechanism is arranged on both sides of the distal end of the slit in the projection of the cutter body which is rotated as a result of being pressed by the aforementioned tissue and feeds the aforementioned tissue toward the interior of the slit. 
     The body tissue harvesting instrument according to another aspect of the present invention is provided with an insertion member which has a distal end and a proximal end part wherein the distal end is inserted first into the body and a cutter which is provided at the distal end of the insertion member and which severs tissue inside the body. Furthermore, the cutter includes a cutter body having a proximal end part held at the distal end of the insertion member, a projection which projects from the distal end of the insertion member, and a slit which extends from the projection toward the proximal end part. A first high-frequency electrode is disposed along the two side edges of the slit on the outer surface of the cutter body. A second high-frequency electrode is disposed at the base end of the slit in the cutter body. The parts located on both sides of the distal end of the slit in the projection of the cutter body mutually separate in the thickness direction of the slit which crosses both the extension direction and width direction of the slit. 
     The body tissue harvesting instrument according to yet another aspect of the present invention is provided with an insertion member which has a distal end and a proximal end wherein the distal end is inserted first into the body and a cutter which is provided at the distal end of the insertion member and which severs tissue inside the body. Furthermore, the cutter includes a cutter body which includes a proximal end part held at the distal end of the insertion member, a projection which projects from the distal end of the insertion member, and a slit which extends from the projection toward the proximal end part. A first high-frequency electrode is disposed along the two side edges of the slit on the outer surface of the cutter body. A second high-frequency electrode is capable of moving between the base end and distal end of the slit in the cutter body. Furthermore, the width of the distal end of the slit is set wider than the width of the base end of the slit. 
     The elongate body tissue harvesting instrument according to yet another aspect of the present invention is provided with an insertion member which has a distal end and a proximal end part wherein the distal end is inserted first into the body. A tissue holder is provided at the distal end of the insertion member which holds tissue inside the body so that it is capable of freely moving along the aforementioned tissue. A cutter is provided at the distal end of the insertion member which severs the aforementioned tissue held by the tissue holder. The tissue holder and cutter at the distal end of the insertion member mutually separate in a first crosswise direction which crosses a longitudinal center line connecting the distal end and the proximal end of the insertion member. Furthermore, the tissue holder includes a tissue holding frame which has a distal end part which projects from the distal end of the insertion member and which is far from the distal end of the insertion member. A proximal end part is closer to the distal end of the insertion member than the distal end part; and two arms extend in a second crosswise direction that crosses both the aforementioned longitudinal center line and the aforementioned first crosswise direction at both the distal end part and proximal end part, and which face each other in the direction along the aforementioned longitudinal center line. The two arms of the tissue holding frame mutually diverge in the first crosswise direction. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute 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 an oblique view which schematically shows the external appearance of the entirety of the body tissue harvesting instrument according to an embodiment of the present invention. 
         FIG. 2A ,  FIG. 2B , and  FIG. 2C  are schematic plan views which sequentially show the procedure whereby a first embodiment of the cutter used in the body tissue harvesting instrument shown in  FIG. 1  presses against in vivo body tissue (in this case, a vein in the leg of a human body), and severs the aforementioned body tissue. 
         FIG. 3A ,  FIG. 3B , and  FIG. 3C  are schematic plan views which sequentially show the procedure whereby a second embodiment of the cutter used in the body tissue harvesting instrument shown in  FIG. 1  presses against in vivo body tissue (in this case, a vein in the leg of a human body), and severs the aforementioned body tissue. 
         FIG. 4A  is a schematic plan view of a third embodiment of the cutter used in the body tissue harvesting instrument illustrated in  FIG. 1 . 
         FIG. 4B  is a schematic frontal view of the third embodiment of the cutter illustrated in  FIG. 4A . 
         FIG. 4C  is a schematic side view of the third embodiment of the cutter illustrated in  FIG. 4A . 
         FIG. 5A  is a schematic oblique view of one embodiment of the tissue holder used in the body tissue harvesting instrument shown in  FIG. 1 . 
         FIG. 5B  is a schematic side view of the tissue holder illustrated in  FIG. 5A . 
         FIG. 6A  is a schematic plan view of a first state of use of a fourth embodiment of the cutter used in the body tissue harvesting instrument illustrated in  FIG. 1 . 
         FIG. 6B  is a schematic plan view of a second state of use of the fourth embodiment of the cutter illustrated in  FIG. 6A . 
         FIG. 7A  is a schematic plan view of a first state of use of a fifth embodiment of the cutter used in the body tissue harvesting instrument illustrated in  FIG. 1 . 
         FIG. 7B  is a schematic plan view of a second state of use of the fifth embodiment of the cutter illustrated in  FIG. 7A . 
         FIG. 8A  is a schematic plan view of a first state of use of a sixth embodiment of the cutter used in the body tissue harvesting instrument illustrated in  FIG. 1 . 
         FIG. 8B  is a schematic plan view of a second state of use of the sixth embodiment of the cutter illustrated in  FIG. 8A . 
         FIG. 9A  and  FIG. 9B  are schematic plan views which sequentially show the procedure whereby a seventh embodiment of the cutter used in the body tissue harvesting instrument shown in  FIG. 1  presses against in vivo body tissue (in this case, a vein in the leg of a human body), and severs the aforementioned body tissue. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     First, the overall configuration of a body tissue harvesting instrument  10  according to one embodiment of the present invention is described with reference to  FIG. 1 . The elongate body tissue harvesting instrument  10  is provided with an insertion member  12  which has a distal end  12   a  and proximal end part  12   b  where the distal end  12   a  is inserted first into the body. The insertion member  12  has a central aperture  12   c  which extends from the proximal end part  12   b  to the distal end  12   a . An endoscope holder  12   d  which communicates with the central aperture  12   c  is set in the proximal end part  12   b . In the central aperture  12   c , an endoscope insertion part is provided which allows insertion of an endoscope  14  from the endoscope holder  12   d  to the distal end  12   a . The endoscope  14  inserted into the endoscope insertion part of the central aperture  12   c  is removably held by the endoscope holder  12   d . The tip of the endoscope  14  is disposed at the distal end  12   a  in the central aperture  12   c  of the insertion member  12 . A monitor television which is not illustrated in the drawing is connected to the proximal end of the endoscope  14 . Accordingly, the images captured via the observation window arranged at the foremost part of the tip of the endoscope  14  (that is, images of the tissue inside the body facing the distal end  12   a  of the insertion member  12 ) can be projected and observed on the screen of the aforementioned monitor television. 
     At the distal end  12   a  of the insertion member  12 , a tissue holder  16  is provided which holds the tissue inside the body (as mentioned above, a vein inside the leg of a human body) and which is capable of freely moving along the aforementioned tissue. The distal end  12   a  of the insertion member  12  is further provided with a cutter  18  which severs the collateral venous branches which are part of the aforementioned tissue held by the tissue holder  16 . The tissue holder  16  and cutter  18  at the distal end  12   a  of the insertion member  12  mutually separate in a first crosswise direction (e.g., the diametric direction of the insertion member  12 ) which crosses a longitudinal center line connecting the distal end  12   a  and proximal end part  12   b  of the insertion member  12 . The cutter  18  is attached to the tip of a cutter manipulation member  20  which extends inside the insertion member  12  from the proximal end part  12   b  to the distal end  12   a  so as to be capable of freely moving forward or backward in the aforementioned longitudinal direction. The proximal end part of the cutter manipulation member  20  is fixed to a cutter manipulation slider  20   a  which is exposed on the outer surface of the proximal end part  12   b  of the insertion member  12  so as to be capable of freely moving forward or backward in the aforementioned longitudinal direction. 
     As described in detail below, the cutter  18  has two high-frequency electrodes, which are not illustrated in  FIG. 1 . Two conductive wires for the two high-frequency electrodes extend inside the insertion member  12  from the distal end  12   a  to the proximal end part  12   b  along the cutter manipulation member  20 . The aforementioned two conductive wires  22   a  and  22   b  extend from the proximal end part  12   b  to the outside, where they connect to a conventional high-frequency power source, which is not illustrated in  FIG. 1 . 
     The configuration of the tissue holder  16  is described in detail below, but the aforementioned configuration for the most part extends from the distal end  12   a  of the insertion member  12 , and is fixed to the distal end  12   a , while a portion of the aforementioned configuration projects from the distal end  12   a  of the insertion member  12 , and attaches to the tip of a tissue holder switching manipulation member  24 . The tissue holder switching manipulation member  24  extends inside the insertion member  12  from the distal end  12   a  to the proximal end part  12   b  so as to be capable of freely moving forward or backward in the aforementioned longitudinal direction, and the proximal end part of the tissue holder switching manipulation member  24  is fixed to a tissue holder switching slider  24   a  which is exposed on the outer surface of the proximal end part  12   b  of the insertion member  12  so as to be capable of freely moving forward or backward in the aforementioned longitudinal direction. 
     At least one or the other of the tissue holder  16  and cutter  18  is capable of moving forward or backward along the longitudinal center line of the insertion member  12  relative to the distal end  12   a  of the insertion member  12  between a facing position where the tissue holder  16  and cutter  18  face each other, and a facing separation position where the cutter  18  is brought closer to the distal end  12   a  of the insertion member  12  than the tissue holder  16 . In this embodiment, as stated above, the cutter  18  is capable of moving forward or backward between the facing position and the facing separation position by moving forward or backward along the longitudinal center line of the insertion member  12  relative to the distal end  12   a  of the insertion member  12 . In  FIG. 1 , the cutter  18  is arranged at the facing separation position relative to the tissue holder  16 . 
     By manipulating the cutter manipulation slider  20   a , and by distancing the cutter  18  at the facing separation position of  FIG. 1  from the distal end  12   a  of the insertion member  12 , it is possible to dispose the cutter  18  in the facing position relative to the tissue holder  16 . Next, a description of the configuration and operation of a first embodiment of the cutter  18  used in the body tissue harvesting instrument  10  illustrated in  FIG. 1  is given, with reference to  FIG. 2A  through  FIG. 2C . 
     The first embodiment of configuration of the cutter  18  is provided with a cutter body  30  of non-conductive material which includes a proximal end part  30   a  held in the distal end  12   a  of the insertion member  12  by attachment to the tip of the cutter manipulation member  20  located at the distal end  12   a  of the insertion member  12 , and a projection  30   b  which projects from the distal end  12   a  of the insertion member  12 . The cutter body  30  further includes a slit  30   c  which opens in the projection  30   b  and which extends from the projection  30   b  toward the proximal end part  30   a.    
     A first high-frequency electrode  32   a  is disposed along the two side edges of the slit  30   c  on the outer surface of the cutter body  30 , and a second high-frequency electrode  32   b  is disposed at the inner end of the slit  30   c  in the cutter body  30 . As stated above with reference to  FIG. 1 , the first high-frequency electrode  32   a  and second high-frequency electrode  32   b  are connected to the aforementioned conventional high-frequency power source (not illustrated in  FIG. 1 ) by the two conductive wires  22   a  and  22   b  which extend inside the insertion member  12  from the distal end  12   a  to the proximal end part  12   b  along the cutter manipulation member  20 . 
     At the distal end of the slit  30   c  in the projection  30   b  of the cutter body  30 , a feeding mechanism  34  is provided which rotates as a result of being pressed by a portion of the desired tissue inside the body (e.g., a venous collateral branch which is part of a desired vein inside the leg of a human body), and which feeds elongate tissue toward the interior of the slit  30   c.    
     In further detail, with respect to this first embodiment of the cutter  18 , the feeding mechanism  34  includes two rotary members  34   a  which rotate so that the parts which are arranged opposite each other on the two sides of the distal end of the slit  30   c  in the projection  30   b  of the cutter body  30  move in a direction from the distal end toward the base end of the slit  30   c . On the respective circumferential faces of the two rotary members  34   a , a conventional slippage stopper is arranged so as to minimize as much as possible slippage of the desired portion of tissue inside the body (e.g., venous collateral branch which is part of a desired vein inside the leg of a human body) which makes contact with these circumferential faces. As stated above with reference to  FIG. 1 , the distal end  12   a  of the insertion member  12  associated with the cutter body  30  of the first embodiment of the cutter  18  is oriented toward the desired tissue site inside the body (e.g., the desired vein inside the leg of a human body) under observation by the endoscope  14 . Subsequently, the tissue holder switching slider  24   a  at the proximal end part  12   b  of the insertion member  12  is manipulated, and the aforementioned desired tissue site inside the body is removably held by the tissue holder  16  (see  FIG. 1 ). 
     Next, the proximal end part  12   b  of the insertion member  12  is manipulated so that the tissue holder  16  is moved along the aforementioned desired tissue site inside the body (e.g., the desired vein inside the leg of a human body). As a result, as shown in  FIG. 2A , the distal end of the slit  30   c  of the projection  30   b  of the cutter body  30  of the first embodiment of the cutter  18  is made to approach a portion of the desired tissue site BV inside the body (e.g., a collateral branch of the aforementioned desired vein inside a leg). 
     Next, as shown in  FIG. 2B , the cutter manipulation slider  20   a  of the cutter manipulation member  20  is advanced, and at least one of the circumferential faces of the two rotary members  34   a  of the feeding mechanism  34  of the projection  30   b  of the cutter body  30  presses against a portion of the aforementioned desired tissue site BV (e.g., the collateral branch of the aforementioned desired vein inside a leg). As a result, at least one of the two rotary members  34   a  rotates so that the portion of the aforementioned desired tissue site BV moves in the direction from the distal end toward the base end of the slit  30   c.    
     When the cutter manipulation slider  20   a  of the cutter manipulation member  20  is further pressed, the portion of the aforementioned desired tissue site BV contacts the portion of the feeding mechanism  34  where the two circumferential faces of the two rotary members  34   a  face each other at the distal end of the slit  30   c . As a result, as shown in  FIG. 2C , the portion of the aforementioned desired tissue site BV is pressed and flattened by the two circumferential faces of the two rotary members  34   a , and is pressed against the second high-frequency electrode  32   b  at the base end of the slit  30   c.    
     High-frequency current flows from the aforementioned high-frequency power source which is not illustrated in the drawings to the first high-frequency electrode  32   a  disposed along the two side edges of the slit  30   c  on the outer surface of the cutter body  30  and the second high-frequency electrode  32   b  disposed at the base end of the slit  30   c  via the two conductive wires  22   a  and  22   b  illustrated in  FIG. 1 , and during this time the cutter manipulation slider  20   a  of the cutter manipulation member  20  is further pressed. As a result, a portion of the aforementioned desired tissue site BV flattened in the slit  30   c  is severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
     Next, a description of the configuration and operation of a second embodiment of the cutter  18  used in the body tissue harvesting instrument  10  illustrated in  FIG. 1  is given, with reference to  FIG. 3A  through  FIG. 3C . Most of the configuration of the second embodiment of the cutter  18  is identical to most of the configuration of the first embodiment of the cutter  18 , which was described above with reference to  FIG. 2A  through  FIG. 2C . Components of the second embodiment of the cutter  18  which are identical to the configuration of the first embodiment of the cutter  18  are given reference codes identical to the reference codes assigned to the corresponding components in the first embodiment of the cutter  18 , and detailed description of these components is omitted. 
     The second embodiment of the cutter  18  differs from the first embodiment of the cutter  18  with respect to the configuration of the feeding mechanism  34 . Specifically, the feeding mechanism  34  includes two rotary members  36   a  which rotate so that the parts which are disposed opposite each other on both sides of the distal end of the slit  30   c  in the projection  30   b  of the cutter body  30  move in the direction from the distal end toward the base end of the slit  30   c . The feeding mechanism  34  further includes two subsidiary rotary members  36   b  which rotate so that the parts which are disposed opposite each other on both sides of the base end of the slit  30   c  at the base end part  30   a  of the cutter body  30  move in the direction from the distal end toward the base end of the slit  30   c . Two gear members or belts  36   c  engage with each of the aforementioned two rotary members  36   a  and each of the aforementioned two subsidiary rotary members  36   b , respectively, and they move the parts which extend opposite each other along the two side edges of the slit  30   c  in the direction from the distal end toward the base end of the slit  30   c  in conjunction with the rotation of each of the two rotary members  36   a  and each of the two subsidiary rotary members  36   b . On the respective circumferential faces of the two rotary members  36   a  and the two subsidiary rotary members  36   b , a conventional slippage stopper is arranged so as to minimize as much as possible slippage relative to the gear members  36   c  which engage with these. Each of the two gear members  36   c  are flexible, and a conventional slippage stopper is arranged so as to minimize slippage as much as possible relative to the portion of desired tissue inside the body (e.g., the venous branches which are part of a desired vein inside a leg of the human body) which contacts these. 
     As stated above with reference to  FIG. 1 , the distal end  12   a  of the insertion member  12  associated with the cutter body  30  of the second embodiment of the cutter  18  is oriented toward the desired tissue site inside the body (e.g., the desired vein inside a leg of the human body) under the observation of the endo scope  14 . Subsequently, the tissue holder switching slider  24   a  of the proximal end part  12   b  of the insertion member  12  is manipulated, and the aforementioned desired tissue site inside the body is removably held by the tissue holder  16  (see  FIG. 1 ). 
     Next, the proximal end part  12   b  of the insertion member  12  inside the body (e.g., inside a leg of the human body) is manipulated so that the tissue holder  16  is moved along the desired site of the aforementioned elongate tissue inside the body (e.g., the desired vein inside a leg of the human body). As a result, as shown in  FIG. 3A , the distal end of the slit  30   c  of the projection  30   b  of the cutter body  30  of the second embodiment of the cutter  18  is made to approach the desired tissue site inside the body BV. 
     Next, when the cutter manipulation slider  20   a  of the cutter manipulation member  20  is advanced, and when the outer surface of the gear member  36   c  on at least one of the circumferential faces of the two rotary members  36   a  of the feeding mechanism  34  of the projection  30   b  of the cutter body  30  presses against a portion of the aforementioned desired tissue site BV, at least one of the aforementioned gear members  36   c  moves so that the aforementioned portion of the desired tissue site BV is fed in the direction from the distal end toward the base end of the slit  30   c , while at least one of the aforementioned rotary members  36   a  and at least one of the subsidiary rotary members  36   b  corresponding thereto rotate in the direction from the distal end toward the base end of the slit  30   c . When the cutter manipulation slider  20   a  of the cutter manipulation member  20  is further pressed, as shown in  FIG. 3B , the aforementioned portion of the desired tissue site BV (e.g., venous branch of the aforementioned desired vein inside a leg) is squeezed by the outer surfaces of the two gear members  36   c  on the two circumferential faces of the two rotary members  36   a  of the feeding mechanism  34  at the distal end of the slit  30   c . Subsequently, the two gear members  36   c  move so that the aforementioned portion of the desired tissue site BV is fed toward the interior of the slit  30   c  by the parts which extend opposite each other along the two side edges of the slit  30   c.    
     As a result, as shown in  FIG. 3C , the aforementioned portion of the desired tissue site BV which has been pressed and flattened by the parts which extend opposite each other along the two side edges of the slit  30   c  in the two gear members  36   c  are pressed against the second high-frequency electrode  32   b  at the base end of the slit  30   c . High-frequency current flows from the aforementioned high-frequency power source (not shown) to the first high-frequency electrode  32   a  disposed along the two side edges of the slit  30   c  on the outer surface of the cutter body  30  and the second high-frequency electrode  32   b  at the base end of the slit  30   c  via the two conductive wires  22   a  and  22   b  illustrated in  FIG. 1 , and during this time the cutter manipulation slider  20   a  of the cutter manipulation member  20  is further pressed. As a result, the aforementioned portion of the desired tissue site BV which has been flattened in the slit  30   c  is severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
     Next, a description of the configuration and operation of a third embodiment of the cutter  18  used in the body tissue harvesting instrument  10  illustrated in  FIG. 1  is given, with reference to  FIG. 4A  through  FIG. 4C . 
     Most of the configuration of the third embodiment of the cutter  18  is identical to most of the configuration of the first embodiment of the cutter  18  which was described above with reference to  FIG. 2A  through  FIG. 2C . Components of the third embodiment of the cutter  18  which are identical to the configuration of the first embodiment of the cutter  18  are given reference codes identical to the reference codes assigned to the corresponding components in the first embodiment of the cutter  18 , and detailed description of these components is omitted. 
     The third embodiment of the cutter  18  differs from the first embodiment of the cutter  18  in that it is not provided with the feeding mechanism  34 , and instead, parts PP 1  and PP 2  located on both sides of the distal end of the slit  30   c  in the projection  30   b  of the cutter body  30  mutually separate in the thickness direction DD of the slit which crosses both the extension direction ED and width direction WD of the slit  30   c.    
     In further detail, in the third embodiment of this cutter  18 , the distance L with which parts PP 1  and PP 2 —which are located on both sides of the distal end of the slit  30   c  in the projection  30   b  of the cutter body  30 —mutually separate in the thickness direction DD of the slit which crosses both the extension direction ED and width direction WD of the slit  30   c  is larger than the width W at the base end of the slit  30   c.    
     As shown by the double-dot-and-dash line in  FIG. 4B , if constituted in this way, and if there is a portion of the aforementioned desired tissue site BV with a diameter smaller than the aforementioned distance L, it can be easily introduced into the distal end of the slit  30   c  by the parts PP 1  and PP 2  which are located on both sides of the distal end of the slit  30   c  in the projection  30   b  of the cutter body  30 . Subsequently, when the cutter manipulation slider  20   a  of the cutter manipulation member  20  is further pressed, the portion of the aforementioned desired tissue site BV which has been introduced is flattened and pressed by the movement toward the interior of the slit  30   c  and by the two side faces of the slit  30   c  so that it approaches the aforementioned width W. 
     The aforementioned portion of the desired tissue site BV which has been flattened is then pressed against the second high-frequency electrode  32   b  at the base end of the slit  30   c . High-frequency current flows under manual control of the surgeon or technician to the first high-frequency electrode  32   a  located along the two sides of the slit  30   c  on the outer surface of the cutter body  30  and to the second high-frequency electrode  32   b  at the base end of the slit  30   c  via the two conductive wires  22   a  and  22   b  illustrated in  FIG. 1  from the aforementioned high-frequency power source (not shown), and during this time the cutter manipulation slider  20   a  of the cutter manipulation member  20  is further pressed. As a result, the aforementioned portion of the desired tissue site BV which is flattened in the slit  30   c  is severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
     Next, a description of the configuration and operation of a first embodiment of the tissue holder  16  used in the body tissue harvesting instrument  10  illustrated in  FIG. 1  is given, with reference to  FIG. 5A  and  FIG. 5B . 
     The tissue holder  16  includes a tissue holding frame  40  which projects from the distal end  12   a  of the insertion member  12  and which is fixed to the distal end  12   a . The tissue holding frame  40  includes a distal end part  40   a  which is far from the distal end  12   a  of the insertion member  12 ; a proximal end part  40   b  which is closer to the distal end  12   a  of the insertion member  12  than the distal end part  40   a ; and two arms  40   c  and  40   d  which extend in a second crosswise direction (e.g., the width direction WD of the slit  30   c  of the cutter body  30  of the cutter  18 ) that crosses—at both the distal end part  40   a  and proximal end part  40   b —both a longitudinal center line LDC of the insertion member  12  and a first crosswise direction (e.g., the diametric direction RD of the insertion member  12 ) that crosses this longitudinal center line LDC, and which face each other in the direction along the aforementioned longitudinal center line LDC. The two arms  40   c  and  40   d  of the tissue holding frame  40  mutually diverge in the first crosswise direction. 
     The tissue holder  16  further includes a frame switching member  40   e  which projects from the distal end  12   a  of the insertion member  12 , and which is able to move forward and backward along the aforementioned longitudinal center line LDC between a closed position where the gap between the mutually extended ends of the two arms  40   c  and  40   d  of the tissue holding frame  40  is closed and an open position where the aforementioned gap is open. 
     In further detail, in this embodiment, the tip of the tissue holder switching manipulation member  24  is held by the aforementioned arm  40   d  of the proximal end part in the tissue holding frame  40  so as to be capable of moving forward or backward along the aforementioned longitudinal center line LDC. At this tip of the tissue holder switching manipulation member  24 , the part which projects into the gap between the arm  40   c  of the distal end part and the arm  40   d  of the proximal end part of the tissue holding frame  40  constitutes the frame switching member  40   e . The frame switching member  40   e  projects from the distal end  12   a  of the insertion member  12  by being integrally formed with (attached to) the tip of the tissue holder switching manipulation member  24 . 
     In  FIG. 5A  and  FIG. 5B , the closed position of the frame switching member  40   e  is illustrated by a double-dotted-and-dashed line, and the open position is illustrated by a solid line. With respect to the cutter  18  at the distal end  12   a  of the insertion member  12  in  FIG. 5A , the facing position which faces the tissue holding frame  40  of the tissue holder  16  is illustrated by a double-dotted-and-dashed line, while the facing separation position which is closer to the distal end  12   a  of the insertion member  12  than the tissue holding frame  40  is illustrated by a solid line. 
     In order to have the tissue holder  16  hold the aforementioned desired tissue site inside the body (e.g., a desired vein inside a leg of the human body), the distal end  12   a  of the insertion member  12  associated with the cutter body  30  of the cutter  18  is oriented toward the desired tissue site inside the body (e.g., a desired vein inside a leg of the human body) under observation by the endoscope  14 , as was previously described with reference to  FIG. 1 . Subsequently, the tissue holder switching slider  24   a  (see  FIG. 1 ) at the proximal end part  12   b  of the insertion member  12  is manipulated, the frame switching member  40   e  of the tissue holder  16  is moved to the open position, the proximal end part  12   b  of the insertion member  12  is further manipulated, and the aforementioned desired tissue site inside the body (e.g., a desired vein inside a leg of the human body) V is made to enter between the two arms  40   c  and  40   d  of the frame switching member  40   e  as shown in  FIG. 5B  via the gap between the extended ends of the two arms  40   c  and  40   d  of the frame switching member  40   e . Finally, the tissue holder switching slider  24   a  at the proximal end part  12   b  of the insertion member  12  is again manipulated, and the frame switching member  40   e  of the tissue holder  16  is moved to the closed position, with the result that the aforementioned desired tissue site inside the body V is removably held by the tissue holder  16 . 
     As shown in  FIG. 5B , the tissue holding frame  40  of the tissue holder  16  is in this state capable of relative movement along the aforementioned desired tissue site inside the body (e.g., a desired vein inside a leg of the human body). Moreover, as the two arms  40   c  and  40   d  of the tissue holding frame  40  mutually diverge in the first crosswise direction (e.g., the diametric direction RD of the insertion member  12 ) which crosses the longitudinal center line (LDC) of the insertion member  12 , during the operation where the aforementioned desired tissue site inside the body (e.g., a desired vein inside a leg of the human body) V is made to enter between the two arms  40   c  and  40   d  of the frame switching member  40   e  as shown in  FIG. 5B  via the gap between the extended ends of the two arms  40   c  and  40   d  of the frame switching member  40   e , it is possible to reduce the angle α established by the longitudinal center line LDC of the insertion member  12  relative to the longitudinal direction VD of the aforementioned desired tissue site inside the body (e.g., a desired vein inside a leg of the human body) V. That is, it is possible to have the aforementioned operation conducted in a state where the longitudinal center line LDC of the insertion member  12  has been brought closer to the longitudinal direction VD of the aforementioned desired tissue site inside the body (e.g., a desired vein inside a leg of the human body) V, and this facilitates the conduct of the aforementioned operation inside the body (e.g., inside a leg of the human body). 
     Next, the proximal end part  12   b  of the insertion member  12  inside the body (e.g., inside a leg of the human body) is manipulated so that the tissue holder  16  moves along the aforementioned desired tissue site inside the body (e.g., a desired vein inside a leg of the human body) V, and the distal end of the slit  30   c  of the projection  30   b  of the cutter body  30  of the cutter  18  is brought closer to a portion of the aforementioned desired tissue site V (e.g., venous collateral of the aforementioned desired vein inside a leg) where a collateral branch BV is located. 
     Next, the cutter manipulation slider  20   a  of the cutter manipulation member  20  (see  FIG. 1 ) is advanced, and a portion of the aforementioned desired tissue site BV is introduced into the interior of the slit  30   c  of the projection  30   b  of the cutter body  30 . During this time, the aforementioned portion of the desired tissue site BV is pressed and flattened by the two side edges of the slit  30   c , and the aforementioned portion of the desired tissue site BV is pressed against the second high-frequency electrode  32   b  at the base end of the slit  30   c . Furthermore, when high-frequency current flows from the aforementioned high-frequency power source to the first high-frequency electrode  32   a  disposed along the two side edges of the slit  30   c  on the outer surface of the cutter body  30  and the second high-frequency electrode  32   b  at the inner end of the slit  30   c  via the two conductive wires  22   a  and  22   b  illustrated in  FIG. 1 , the aforementioned portion of the desired tissue site BV which has been flattened is severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
     Next, a description of the configuration and operation of a fourth embodiment of the cutter  18  used in the body tissue harvesting instrument  10  illustrated in  FIG. 1  is given, with reference to  FIG. 6A  and  FIG. 6B . Most of the configuration of the fourth embodiment of the cutter  18  is identical to most of the configuration of the first embodiment of the cutter  18  which was described above with reference to  FIG. 2A  through  FIG. 2C . Components of the fourth embodiment of the cutter  18  which are identical to the configuration of the first embodiment of the cutter  18  are given reference codes identical to the reference codes assigned to the corresponding components in the first embodiment of the cutter  18 , and detailed description of these components is omitted. 
     The fourth embodiment of the cutter  18  differs from the first embodiment of the cutter  18  in that it is not provided with the feeding mechanism  34 , instead of which the width of the distal end of the slit  30   c  of the cutter body  30  is set larger than the width of the base end of the slit  30   c , and the second high-frequency electrode  32   b  in the slit  30   c  moves freely between the base end and a position near the distal end of the slit  30   c . In further detail, in this embodiment, the slit  30   c  has a triangular shape where the base end constitutes one apex, or it forms a V-shape where the width widens as one moves from the base end toward the distal end. 
     The movement of the second high-frequency electrode  32   b  in the aforementioned manner is conducted by manipulating the base end part of the second high-frequency electrode manipulation member (not shown) and which extends from the base end part  30   b  of the cutter body  30  in the insertion member  12  (see  FIG. 1 ) to the proximal end part  12   b  of the insertion member  12  along the cutter manipulation member  20 . 
     In this fourth embodiment of the cutter  18 , if there is a portion of a desired tissue site inside the body of an organism BV which is capable of being introduced into the distal end of the triangular or V-shaped slit  30   c , it is possible to press the second high-frequency electrode  32   b  against the outer circumferential face of the aforementioned portion of the desired tissue site BV which has been introduced into the distal end of the triangular or V-shaped slit  30   c.    
       FIG. 6A  shows a first condition where a portion of the aforementioned desired tissue site BV which has a diameter slightly larger than the width of the base end of the slit  30   c  has been introduced into the triangular or V-shaped slit  30   c , and is pressed against the second high-frequency electrode  32   b  at the aforementioned base end. In this condition, while high-frequency current is flowing in the above-described manner to the first and second high-frequency electrodes  32   a  and  32   b , if the cutter body  30  is pressed along with the second high-frequency electrode  32   b  toward the aforementioned portion of the desired tissue site of small diameter BV, the aforementioned portion of the desired tissue site of small diameter BV which has been flattened and pressed against the second high-frequency electrode  32   b  is severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
       FIG. 6B  shows a second condition where a portion of the aforementioned desired tissue site BV which has a diameter slightly smaller than the width of the distal end of the slit  30   c  has been introduced into the triangular or V-shaped slit  30   c , and is held by the distal ends of the two side faces of the slit  30   c , and where—if it is not possible to move any further toward the base end of the slit  30   c —the base end of the aforementioned second high-frequency electrode manipulation member (not shown) is manipulated, the second high-frequency electrode  32   b  is moved from the base end toward the distal end of the slit  30   c , and the second high-frequency electrode  32   b  is pressed against the outer circumferential face of the aforementioned portion of the desired tissue site of large diameter BV which is held. 
     In this condition, while high-frequency current is flowing in the above-described manner to the first and second high-frequency electrodes  32   a  and  32   b , if the cutter body  30  is pressed along with the second high-frequency electrode  32   b  toward the aforementioned portion of the desired tissue site of large diameter BV, the aforementioned portion of the desired tissue site of large diameter BV which has been flattened and pressed against the second high-frequency electrode  32   b  is severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
     Next, a description of the configuration and operation of a fifth embodiment of the cutter  18  used in the body tissue harvesting instrument  10  illustrated in  FIG. 1  is given, with reference to  FIG. 7A  and  FIG. 7B . Most of the configuration of the fifth embodiment of the cutter  18  is identical to most of the configuration of the first embodiment of the cutter  18  which was described above with reference to  FIG. 2A  through  FIG. 2C . Components of the fifth embodiment of the cutter  18  which are identical to the configuration of the first embodiment of the cutter  18  are given reference codes identical to the reference codes assigned to the corresponding components in the first embodiment of the cutter  18 , and detailed description of these components is omitted. 
     The fifth embodiment of the cutter  18  differs from the first embodiment of the cutter  18  in that it is not provided with the feeding mechanism  34 , instead of which the width of the distal end of the slit  30   c  of the cutter body  30  is set larger than the width of the base end of the slit  30   c , and the second high-frequency electrode  32   b  in the slit  30   c  moves freely between the base end and a position near the distal end of the slit  30   c . In further detail, in this embodiment, the slit  30   c  has a shape where the width sequentially widens in a stepwise manner from the base end toward the distal end of the slit  30   c , and the two side edges of the slit  30   c  have a wide part of fixed width which is arranged on the distal end side, and a narrow part of a fixed width narrower than the wide part which is arranged on the base end side. 
     The movement of the second high-frequency electrode  32   b  in the aforementioned manner is conducted by manipulating the base end part of the second high-frequency electrode manipulation member (not shown) and which extends from the base end part  30   b  of the cutter body  30  in the insertion member  12  (see  FIG. 1 ) to the proximal end part  12   b  of the insertion member  12  along the cutter manipulation member  20 . It is then possible to press the second high-frequency electrode  32   b  against the outer circumferential face of a portion of the desired tissue site of large diameter inside the body BV which is capable of being introduced into the wide part of large width on the distal end side of the slit  30   c , and against the outer circumferential face of a portion of the desired tissue site of small diameter inside the body BV which is capable of being introduced into the narrow part of small width on the base end side of the slit  30   c.    
       FIG. 7A  shows a first condition where the aforementioned portion of the desired tissue site BV which has a diameter slightly larger than the aforementioned narrow part is introduced into and flattened by the narrow part on the base end side of the slit  30   c , and is pressed against the second high-frequency electrode  32   b  in the narrow part on the base end side of the slit  30   c . In this condition, while high-frequency current is flowing in the above-described manner to the first and second high-frequency electrodes  32   a  and  32   b , if the cutter body  30  is pressed along with the second high-frequency electrode  32   b  toward the aforementioned portion of the desired tissue site of small diameter BV, the aforementioned portion of the desired tissue site of small diameter BV which has been flattened and pressed against the second high-frequency electrode  32   b  is severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
       FIG. 7B  shows a second condition where a portion of the aforementioned desired tissue site BV which has a diameter slightly larger than the aforementioned wide part has been introduced into and flattened by the wide part on the distal end side of the slit  30   c , and where—if it is not possible to introduce it into the mouth of the narrow part on the base end side of the slit  30   c —the base end of the aforementioned second high-frequency electrode manipulation member (not shown) is manipulated, and the second high-frequency electrode  32   b  is moved from the base end toward the distal end of the slit  30   c , with the result that the second high-frequency electrode is held in the narrow part of the slit  30   c  where it presses against the outer circumferential face of the aforementioned portion of the desired tissue site of large diameter BV which is stopped at the mouth of the narrow part of the slit  30   c . In this condition, while high-frequency current is flowing in the above-described manner to the first and second high-frequency electrodes  32   a  and  32   b , if the cutter body  30  is pressed along with the second high-frequency electrode  32   b  toward the aforementioned portion of the desired tissue site of large diameter BV, the aforementioned portion of the desired tissue site of large diameter BV which has been pressed against the second high-frequency electrode  32   b  is severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
     Next, a description of the configuration and operation of a sixth embodiment of the cutter  18  used in the body tissue harvesting instrument  10  illustrated in  FIG. 1  is given, with reference to  FIG. 8A  and  FIG. 8B . Most of the configuration of the sixth embodiment of the cutter  18  is identical to most of the configuration of the first embodiment of the cutter  18  which was described above with reference to  FIG. 2A  through  FIG. 2C . Components of the sixth embodiment of the cutter  18  which are identical to the configuration of the first embodiment of the cutter  18  are given reference codes identical to the reference codes assigned to the corresponding components in the first embodiment of the cutter  18 , and detailed description of these components is omitted. 
     The sixth embodiment of the cutter  18  differs from the first embodiment of the cutter  18  in that it is not provided with the feeding mechanism  34 , instead of which the width of the distal end of the slit  30   c  of the cutter body  30  is set larger than the width of the base end of the slit  30   c , and the second high-frequency electrode  32   b  in the slit  30   c  moves freely between the base end and a position near the distal end of the slit  30   c . In further detail, in this embodiment, the slit  30   c  has a triangular shape where the base end constitutes one apex, or it forms a V-shape where the width widens as one moves from the base end toward the distal end. Furthermore, by means of a conventional energizing member  42  which is interposed between the cutter body  30  and the second high-frequency electrode  32   b , the second high-frequency electrode  32   b  is impelled toward a position near the distal end of the slit  30   c . The conventional energizing member  42  includes, for example, an elastic member typified by a spring or rubber. 
     In this sixth embodiment of the cutter  18 , if there is a portion of a desired tissue site inside the body of an organism (e.g., a collateral venous branch of the aforementioned desired vein inside a leg) BV which is capable of being introduced into the distal end of the triangular or V-shaped slit  30   c , it is possible to have the outer circumferential face of the aforementioned portion of the desired tissue site BV which has been introduced into the distal end of the triangular or V-shaped slit  30   c  exert pressure on the second high-frequency electrode  32   b , and to press the second high-frequency electrode  32   b  against the outer circumferential face of the aforementioned portion of the desired tissue site BV by means of the energizing force of the conventional energizing member  42 , which resists this pressure. 
       FIG. 8A  shows a first condition where a portion of the aforementioned desired tissue site BV which has a diameter slightly larger than the width of the distal end of the slit  30   c  has been introduced into the triangular or V-shaped slit  30   c , is held at the distal ends of the two side faces of the slit  30   c , and is unable to move any further toward the base end of the slit  30   c . Even in this first condition, as the outer circumferential face of the aforementioned portion of the desired tissue site of large diameter BV which is held at the distal ends of the two side faces of the slit  30   c  exerts pressure on the second high-frequency electrode  32   b , the second high-frequency electrode  32   b  presses against the outer circumferential face of the aforementioned portion of the desired tissue site of large diameter BV by means of the energizing force of the conventional energizing member  42 , which resists this pressure. 
     In this condition, while high-frequency current is flowing in the above-described manner to the first and second high-frequency electrodes  32   a  and  32   b , if the cutter body  30  is pressed toward the aforementioned portion of the desired tissue site of large diameter BV, the aforementioned portion of the desired tissue site of large diameter BV which is pressed against the second high-frequency electrode  32   b  is severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
       FIG. 8B  shows a second condition where a portion of the aforementioned desired tissue site BV which has a diameter slightly larger than the width of the base end of the slit  30   c  has been introduced into the triangular or V-shaped slit  30   c , and is held at a position near the base end of the two side faces of the slit  30   c.    
     Even in this second condition, as the outer circumferential face of the aforementioned portion of the desired tissue site of small diameter BV which is held at a position near the base end of the two side faces of the slit  30   c  exerts pressure on the second high-frequency electrode  32   b , the second high-frequency electrode  32   b  presses against the outer circumferential face of the aforementioned portion of the desired tissue site of small diameter BV by means of the energizing force of the conventional energizing member  42 , which resists this pressure. In this condition, while high-frequency current is flowing in the above-described manner to the first and second high-frequency electrodes  32   a  and  32   b , if the cutter body  30  is pressed toward the aforementioned portion of the desired tissue site of small diameter BV, the aforementioned portion of the desired tissue site of small diameter BV which is pressed against the second high-frequency electrode  32   b  is severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
     The conventional energizing member  42  used in the sixth embodiment of the cutter  18  described above with reference to  FIG. 8A  and  FIG. 8B  would be able to function in a manner identical to the above-described case of the sixth embodiment of the cutter  18  were it to be interposed between the cutter body  30  and the second high-frequency electrode  32   b  in the fifth embodiment of the cutter  18  described above with reference to  FIG. 7A  and  FIG. 7B . 
     Next, a description of the configuration and operation of a seventh embodiment of the cutter  18  used in the body tissue harvesting instrument  10  illustrated in  FIG. 1  is given, with reference to  FIG. 9A  and  FIG. 9B . Most of the configuration of the seventh embodiment of the cutter  18  is identical to most of the configuration of the first embodiment of the cutter  18  which was described above with reference to  FIG. 2A  through  FIG. 2C . Components of the seventh embodiment of the cutter  18  which are identical to the configuration of the first embodiment of the cutter  18  are given reference codes identical to the reference codes assigned to the corresponding components in the first embodiment of the cutter  18 , and detailed description of these components is omitted. 
     The seventh embodiment of the cutter  18  differs from the first embodiment of the cutter  18  in that it is not provided with the feeding mechanism  34 , instead of which multiple slits  30   c  whose respective widths differ are formed in the cutter body  30  so as to be mutually independent. The multiple slits  30   c  extend in a mutually parallel manner from the projecting end part  30   b  toward the base end part  30   a  of the cutter body  30 . In this seventh embodiment of the cutter  18 , illustrated in  FIG. 9A  and  FIG. 9B , two slits  30   c  are formed in the cutter body  30 , but the number of multiple slits  30   c  formed in the cutter body  30  may be more than two so long as the concept of this invention is followed. 
     In the seventh embodiment of the cutter  18  which is configured in the aforementioned manner, when a portion of a desired tissue site of large diameter inside the body of an organism BV which has a diameter slightly larger than the slit  30   c  of large width illustrated in  FIG. 9A , and when a portion of a desired tissue site of small diameter inside the body of an organism BV which has a diameter slightly larger than the slit  30   c  of small width are respectively introduced into and flattened by the slit  30   c  of large width and the slit  30   c  of small width, they press against the second high-frequency electrode  32   b  at the base ends of the respective slits  30   c  as shown in  FIG. 9B . 
     In this condition, while high-frequency current is flowing in the above-described manner to the first and second high-frequency electrodes  32   a  and  32   b , if the cutter body  30  is pressed along with the second high-frequency electrode  32   b  toward the aforementioned portion of the desired tissue site of small diameter BV and toward the aforementioned portion of the desired tissue site of large diameter BV, the aforementioned portion of the desired tissue site of small diameter BV and the aforementioned portion of the desired tissue site of large diameter BV which have been pressed and flattened against the second high-frequency electrode  32   b  are severed by the high-frequency current which flows between the first high-frequency electrode  32   a  and second high-frequency electrode  32   b , and the severed portion is clotted. 
     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.