Patent Publication Number: US-2023137591-A1

Title: Endoscope treatment tool, and treatment method

Description:
RELATED APPLICATION DATA 
     This application is based on and claims priority under 35 U.S.C. § 119 to U.S. Provisional Application No. 63/273,172, filed Oct. 29, 2021, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     The disclosure relates to an endoscope treatment tool, and a treatment method. 
     BACKGROUND 
     In Endoscopic Submucosal Dissection (ESD), treatment tools for incision and dissection, such as high frequency knives, and treatment tools for local injection and hemostasis are used (see, for example, CN 111202485 A, JP 2012-523863 A, and CN 108272503 A). 
     CN 111202485 A and JP 2012-523863 A disclose treatment tools for an endoscope, which are capable of performing tissue incision treatment and local injection treatment. 
     In addition, in a case where local injection treatment is performed, as disclosed in CN 108272503 A, a method of locally injecting a liquid into a tissue by discharging the liquid from a distal end of an electrode for incision or dissection is known. 
     SUMMARY 
     In some embodiments, an endoscope treatment tool includes a sheath, an electrode and a needle. The sheath includes a first hole opened at a distal end of the sheath. The electrode is inserted into the first hole and includes a second hole opened at a distal end of the electrode. The needle is inserted into the second hole. The needle is movable to protrude from a distal end of the second hole of the electrode. A gap between the electrode and the needle is configured to pass a fluid. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram illustrating an endoscope system according to a first embodiment. 
         FIG.  2    is a diagram for describing a configuration of a treatment tool insertion portion. 
         FIG.  3    is a diagram for describing a configuration of a treatment tool insertion portion. 
         FIG.  4    is a diagram for describing a configuration of a treatment tool insertion portion. 
         FIG.  5 A  is a diagram illustrating an example of a shape of a protrusion portion. 
         FIG.  5 B  is a diagram illustrating an example of a shape of a protrusion portion. 
         FIG.  5 C  is a diagram illustrating an example of a shape of a protrusion portion. 
         FIG.  6 A  is a diagram illustrating an example of a shape of a flange portion. 
         FIG.  6 B  is a diagram illustrating an example of a shape of a flange portion. 
         FIG.  6 C  is a diagram illustrating an example of a shape of a flange portion. 
         FIG.  6 D  is a diagram illustrating an example of a shape of a flange portion. 
         FIG.  7    is a diagram for describing an operation of an endoscope treatment tool. 
         FIG.  8    is a diagram for describing an operation of an endoscope treatment tool. 
         FIG.  9    is a diagram for describing an operation of an endoscope treatment tool. 
         FIG.  10    is a diagram for describing an operation of an endoscope treatment tool. 
         FIG.  11    is a diagram illustrating an example of a configuration in a case where a tube is not provided. 
         FIG.  12    is a diagram illustrating a modification of the first embodiment. 
         FIG.  13    is a diagram illustrating a modification of the first embodiment. 
         FIG.  14    is a diagram for describing a configuration of a treatment tool insertion portion according to a second embodiment. 
         FIG.  15    is a diagram for describing a configuration of a treatment tool insertion portion according to the second embodiment. 
         FIG.  16    is a diagram for describing a configuration of a treatment tool insertion portion according to the second embodiment. 
         FIG.  17    is a diagram for describing a configuration of a treatment tool insertion portion according to a third embodiment. 
         FIG.  18    is a diagram for describing a configuration of a treatment tool insertion portion according to the third embodiment. 
         FIG.  19    is a diagram for describing a configuration of a treatment tool insertion portion according to the third embodiment. 
         FIG.  20    is a diagram for describing a configuration of a treatment tool insertion portion according to a fourth embodiment. 
         FIG.  21    is a diagram for describing a configuration of a treatment tool insertion portion according to the fourth embodiment. 
         FIG.  22    is a diagram for describing a configuration of a treatment tool insertion portion according to the fourth embodiment. 
         FIG.  23    is a diagram illustrating a first modification of the first to fourth embodiments. 
         FIG.  24    is a diagram illustrating a second modification of the first to fourth embodiments. 
         FIG.  25    is a diagram illustrating a third modification of the first to fourth embodiments. 
         FIG.  26    is a diagram illustrating a fourth modification of the first to fourth embodiments. 
         FIG.  27    is a diagram illustrating a fifth modification of the first to fourth embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, modes for carrying out the disclosure (hereinafter referred to as embodiments) will be described with reference to the drawings. It is noted that the disclosure is not limited to the embodiments described below. Furthermore, in the description of the drawings, the same reference numerals are assigned to the same parts. 
     First Embodiment 
     Configuration of Endoscope System 
       FIG.  1    is a diagram illustrating an endoscope system  1  according to a first embodiment. 
     The endoscope system  1  is a system that is used in the medical field and treats a site to be treated in a living tissue inside a body cavity (hereinafter referred to as a target site) by applying high frequency energy to the target site while observing the body cavity. It is noted that the treatment that can be performed by the endoscope system  1  according to the first embodiment is a treatment such as coagulation (sealing) of the target site or incision of the target site. As illustrated in  FIG.  1   , the endoscope system  1  includes an endoscope  2 , a display device  3 , a light source device  4 , a control device  5 , and a treatment tool  6  for an endoscope. 
     The endoscope  2  is partially inserted into the body cavity, captures a subject image reflected from the body cavity, and outputs an image signal generated by the image capture. As illustrated in  FIG.  1   , the endoscope  2  includes an endoscope insertion portion  21 , an endoscope operating portion  22 , a universal cord  23 , and a connector portion  24 . 
     The endoscope insertion portion  21  is a portion that is at least partially flexible and is inserted into the body cavity. As illustrated in  FIG.  1   , the endoscope insertion portion  21  includes a distal end unit  211 , a bendable portion  212 , and a flexible tube  213 . 
     The distal end unit  211  is provided at the distal end of the endoscope insertion portion  21 . Although the specific illustration is omitted, the distal end unit  211  is provided with an illumination optical system, an imaging optical system, and an imaging unit. 
     The illumination optical system faces one end of a light guide (not illustrated) routed in the endoscope insertion portion  21  and irradiates light transmitted by the light guide onto the inside of the body cavity from the distal end of the endoscope insertion portion  21 . 
     The imaging optical system irradiates light onto the inside of the body cavity from the illumination optical system, takes in the light (subject image) reflected from the inside of the body cavity, and forms an image on an imaging surface of an image sensor constituting the imaging unit. 
     The imaging unit is configured to include an image sensor, such as a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS). The imaging unit captures a subject image formed by the imaging optical system and outputs an image signal generated by the image capture. 
     The bendable portion  212  is connected to the proximal end side (endoscope operating portion  22  side) of the distal end unit  211 . Although the specific illustration is omitted, the bendable portion  212  has a configuration in which a plurality of curved pieces are connected to each other and the bendable portion  212  can be curved. 
     The flexible tube  213  is connected to the proximal end side (endoscope operating portion  22  side) of the bendable portion  212  and has an elongated shape and flexibility. 
     The endoscope operating portion  22  is connected to the proximal end portion of the endoscope insertion portion  21 . The endoscope operating portion  22  accepts various operations on the endoscope  2 . As illustrated in  FIG.  1   , the endoscope operating portion  22  is provided with a plurality of operation members  221 , a curved knob  222 , and an insertion port  223 . 
     The plurality of operation members  221  are configured by buttons or the like that accept various operations. 
     The curved knob  222  is configured to be rotatable according to a user operation. Therefore, the curved knob  222  rotates to operate a bending mechanism (not illustrated) of a metal or resin wire or the like disposed in the endoscope insertion portion  21 . Due to this, the bendable portion  212  is curved. 
     The insertion port  223  is an insertion port which communicates with a pipeline (not illustrated) extending from the distal end to the proximal end side (endoscope operating portion  22  side) of the endoscope insertion portion  21  and allows a treatment tool insertion portion  7  or the like in the treatment tool  6  for an endoscope to be inserted into the pipeline from the outside. 
     The universal cord  23  is a cord which extends from the endoscope operating portion  22  in a direction different from the extension direction of the endoscope insertion portion  21  and in which the above-described light guide, a signal line for transmitting the above-described image signal, and the like are disposed. 
     The connector portion  24  is provided at the end of the universal cord  23  and is detachably connected to the light source device  4  and the control device  5 . 
     The display device  3  is a Liquid Crystal Display (LCD), an Electro Luminescence (EL) display, or the like, and displays a predetermined image under the control of the control device  5 . 
     The light source device  4  emits illumination light. The illumination light, which is emitted from the light source device  4 , passes through the connector portion  24 , the universal cord  23 , the endoscope operating portion  22 , and the light guide and the illumination optical system routed in the endoscope insertion portion  21 , and is then irradiated from the distal end of the endoscope insertion portion  21  toward the inside of the body cavity. 
     The control device  5  is configured to include a Central Processing Unit (CPU), a Field-Programmable Gate Array (FPGA), and the like, and controls overall operations of the display device  3  and the light source device  4 . 
     For example, the control device  5  generates an endoscopic image by performing predetermined processing on the image signal input from the above-described imaging unit through the above-described signal line. The control device  5  controls the operation of the display device  3  and causes the display device  3  to display the endoscopic image or the like. 
     It is noted that, in the first embodiment, the light source device  4  and the control device  5  are configured separately, but may be integrally provided in one housing. 
     Configuration of treatment tool for endoscope The treatment tool  6  for an endoscope is, for example, a treatment tool used in Endoscopic Submucosal Dissection (ESD). As illustrated in  FIG.  1   , the treatment tool  6  for an endoscope includes the treatment tool insertion portion  7  and a treatment tool operating portion  8 . 
     As illustrated in  FIG.  1   , the treatment tool insertion portion  7  is a portion that passes through the pipeline in the endoscope insertion portion  21  from the insertion port  223 , protrudes from the distal end of the endoscope insertion portion  21 , and is inserted into the body cavity. The treatment tool insertion portion  7  corresponds to an insertion portion. 
     It is noted that the detailed configuration of the treatment tool insertion portion  7  will be described in “Configuration of treatment tool insertion portion” described below. In addition, the “distal end” shown below means one end of the treatment tool insertion portion  7  in the insertion direction, and the “proximal end” shown below means the other end of the treatment tool insertion portion  7  on the side opposite to the insertion direction. 
     The treatment tool operating portion  8  is connected to the proximal end portion of the treatment tool insertion portion  7 . The treatment tool operating portion  8  receives the operation on the treatment tool  6  for an endoscope. As illustrated in  FIG.  1   , the treatment tool operating portion  8  includes an operating portion body  81 , a first slider  82 , and a second slider  83 . 
     The operating portion body  81  has an elongated shape, and a proximal end portion of a sheath  9 , described below, constituting the treatment tool insertion portion  7  is fixed thereto. In addition, as illustrated in  FIG.  1   , a ring  811  for an operator such as an operating surgeon to hang his or her finger is provided at the proximal end portion of the operating portion body  81 . Furthermore, the operating portion body  81  is provided with a water supply port  812  to which a tube TU is connected. A physiological saline solution is supplied from a water supply source  200 , such as a pump, to the water supply port  812  via the tube TU. 
     Here, the physiological saline solution corresponds to a fluid. It is noted that the fluid is not limited to the physiological saline solution, and other liquids and gases such as air may be adopted. 
     The first slider  82  is attached to the operating portion body  81  so as to be movable along the longitudinal direction of the operating portion body  81  according to an operation by an operator such as an operating surgeon. As illustrated in  FIG.  1   , the first slider  82  is provided with a pair of rings  821  for an operator such as an operating surgeon to hang his or her finger. In addition, the first slider  82  is provided with a plug  822  to which a power cord CO is connected. The plug  822  is electrically connected to a power source  100  via the power cord CO. 
     The second slider  83  is attached to the operating portion body  81  so as to be movable along the longitudinal direction of the operating portion body  81  according to an operation by an operator such as an operating surgeon. It is noted that the second slider  83  is movable along the longitudinal direction of the operating portion body  81  in a state of being independent of the first slider  82 . 
     Configuration of Treatment Tool Insertion Portion 
       FIGS.  2  to  4    are diagrams for describing the configuration of the treatment tool insertion portion  7 . Specifically,  FIGS.  2  to  4    are cross-sectional views in which the distal end portion of the treatment tool insertion portion  7  is cut by a plane including the central axis of the treatment tool insertion portion  7 . In addition,  FIG.  2    is a diagram illustrating the treatment tool insertion portion  7  set to a first state.  FIG.  3    is a diagram illustrating the treatment tool insertion portion  7  set to a second state.  FIG.  4    is a diagram illustrating the treatment tool insertion portion  7  set to a third state. 
     As illustrated in  FIGS.  1  to  4   , the treatment tool insertion portion  7  includes a sheath  9 , a first advancing/retreating portion  10  ( FIGS.  2  to  4   ), a knife  11  ( FIGS.  2  to  4   ), a second advancing/retreating portion (wire)  12  ( FIGS.  2  to  4   ), and a needle portion  13  ( FIGS.  2  to  4   ). 
     The sheath  9  is a portion that constitutes the outer surface of the treatment tool insertion portion  7 . As illustrated in  FIGS.  1  to  4   , the sheath  9  includes a sheath body  91  and a distal end part  92 . 
     The sheath body  91  is a cylindrical member made of a resin material or the like and having insulating properties and flexibility. The proximal end portion of the sheath body  91  is fixed to the operating portion body  81 . 
     The distal end part  92  is configured by a substantially cylindrical member. The distal end part  92  may be made of a member having electrical insulating properties, including ceramic, a resin material, rubber, or the like, or may be made of a member on which insulating coating or the like is performed on a surface of a metal or the like. The distal end part  92  is fixed to the distal end portion of the sheath body  91 . More specifically, the distal end part  92  is inserted through the distal end portion of the sheath body  91  and closes the distal end portion thereof. As illustrated in  FIGS.  2  to  4   , the distal end part  92  is provided with a first hole  921  that communicates with the inside and outside of the sheath  9 . 
     The first hole  921  has a circular cross-sectional shape, is located on the central axis of the distal end part  92 , and extends linearly along the central axis thereof. In addition, the first hole  921  has a stepped shape in which the distal end portion has a larger inner diameter than the proximal end portion. In the following, for convenience of explanation, a portion of the first hole  921  having a large inner diameter on the distal end side is referred to as a large diameter portion  9211  ( FIGS.  2  to  4   ), and a portion of the first hole  921  having a small inner diameter on the proximal end side is referred to as a small diameter portion  9212  ( FIGS.  2  to  4   ). In addition, a stepped portion between the large diameter portion  9211  and the small diameter portion  9212  is referred to as a first stepped portion  9213  ( FIGS.  2  to  4   ). 
     The first advancing/retreating portion  10  is a member that has a distal end portion connected to the knife  11 , is capable of advancing and retreating in the sheath body  91 , and advances and retreats the knife  11  along the central axis of the sheath  9 . As illustrated in  FIGS.  2  to  4   , the first advancing/retreating portion  10  includes a tube  14 , a connecting portion  15 , and an inner tube  16 . That is, the first advancing/retreating portion  10  can be said as “a tube” as a whole. 
     The tube  14  is a cylindrical flexible coil that is made of, for example, a conductive material such as a metal, is located inside the sheath  9 , and extends along the central axis of the sheath  9 . The proximal end portion of the tube  14  is fixed to the first slider  82 . That is, the first advancing/retreating portion  10  advances and retreats in the sheath body  91  according to an operation on the first slider  82  by an operator such as an operating surgeon. In addition, the tube  14  is electrically connected to the plug  822 . Furthermore, the inside of the tube  14  communicates with the water supply port  812 . 
     It is noted that the metal tube  14  is not always essential if there is a means for electrically conducting the plug  822  and the knife  11  with a metal wire or the like. 
     The connecting portion  15  is a member that connects the first advancing/retreating portion  10  to the knife  11 . The connecting portion  15  is made of a conductive material such as a metal, is located inside the sheath  9 , and has a cylindrical shape extending linearly along the central axis thereof. As illustrated in  FIGS.  2  to  4   , the tube  14  is fixed to the proximal end side of the connecting portion  15  in a state of being inserted therethrough. Due to this, the inside of the tube  14  communicates with the inside of the connecting portion  15 . That is, the connecting portion  15  advances and retreats in the sheath body  91  together with the tube  14  according to an operation on the first slider  82  by an operator such as an operating surgeon. On the other hand, the knife  11  is fixed to the distal end side of the connecting portion  15  in a state of being inserted therethrough. That is, the connecting portion  15  is fixed on the outer peripheral surface of the proximal end portion of the knife  11 , the knife  11  becomes the whole body together with the tube  14  and the connecting portion  15  according to the operation of the first slider  82 , and the distal end of the connecting portion  15  is configured to abut on the distal end part  92  so that the amount of protrusion of the knife  11  from the distal end part  92  is restricted. 
     The inside of the tube  14  and the inside of the connecting portion  15  described above correspond to a communication hole  101  ( FIGS.  2  to  4   ). The communication hole  101  functions as a passage P 1  ( FIGS.  2  to  4   ), through which the physiological saline solution supplied from the water supply source  200  flows via the tube TU and the water supply port  812 . That is, the first advancing/retreating portion  10  includes an internal channel that forms a passage communicating with a gap between the knife  11  and the needle portion  13 . 
     The inner tube  16  is a cylindrical member made of a resin material or the like and having insulating properties and flexibility and is provided so as to cover the outer peripheral surface of the tube  14  and the outer peripheral surface of the connecting portion  15 . The inner tube  16  prevents the physiological saline solution from leaking out from the passage P 1 . That is, the inner tube  16  advances and retreats in the sheath body  91  together with the tube  14  and the connecting portion  15  according to an operation on the first slider  82  by an operator such as an operating surgeon. 
     The knife  11  may correspond to an electrode. The knife  11  injects the physiological saline solution into the target site via a cut made by the needle portion  13  with respect to the target site. The needle portion  13  may correspond to a needle. In addition, the knife  11  is made of a conductive material such as a metal, and the proximal end portion is fixed in a state of being inserted into the connecting portion  15 . That is, the knife  11  advances and retreats in the sheath body  91  together with the first advancing/retreating portion  10  according to an operation on the first slider  82  by an operator such as an operating surgeon. In addition, the knife  11  protrudes from the first hole  921  to the outside of the distal end part  92 . The knife  11  is energized with a high frequency current from the power source  100  via the power cord CO, the plug  822 , the tube  14 , and the connecting portion  15 , and incises the target site in the body cavity. As illustrated in  FIGS.  2  to  4   , the knife  11  includes a knife body  111  and a protrusion portion  112 . 
     The knife body  111  is located on the central axis of the distal end part  92  and is configured by a cylindrical member extending along the central axis thereof. Here, as illustrated in  FIGS.  2  to  4   , the outer diameter dimension of the knife body  111  is set to be slightly smaller than the inner diameter dimension of the first hole  921 . 
     The protrusion portion  112  is provided at the distal end of the knife body  111  and has a disk shape that is coaxial with the central axis of the knife body  111 . The maximum width dimension of the protrusion portion  112  is set to be larger than the outer diameter dimension of the knife body  111  and slightly smaller than the inner diameter dimension of the large diameter portion  9211 . It is noted that the protrusion portion  112  protrudes and extends radially from the outer peripheral surface of the knife body  111 . 
       FIGS.  5 A to  5 C  are diagrams illustrating an example of the shape of the protrusion portion  112 . 
     Here, the protrusion portion  112  does not necessarily have to have a disk shape. As illustrated in  FIGS.  5 A to  5 C , the protrusion portion  112  may have a flange shape such as a hemispherical shape ( FIG.  5 A ) or a triangular shape ( FIG.  5 B ). The protrusion portion  112  is not limited to the flange shape, and may have a hook shape ( FIG.  5 C ). 
     As illustrated in  FIGS.  2  to  4   , the knife  11  described above is provided with a second hole  113  that is located on the central axis of the knife body  111  and penetrates from the proximal end to the distal end of the knife  11  along the central axis thereof. The second hole  113  communicates with the passage P 1  by connecting the knife  11  to the first advancing/retreating portion  10 . 
     The second advancing/retreating portion  12  is, for example, a wire made of a metal material, and is a member that is connected to the proximal end portion of the knife  11 , can advance and retreat relative to the first advancing/retreating portion  10  in the communication hole  101 , and advances and retreats the needle portion  13  along the central axis of the sheath  9 . The second advancing/retreating portion  12  is fixed to the second slider  83 . That is, the second advancing/retreating portion  12  advances and retreats in the communication hole  101  according to an operation on the second slider  83  by an operator such as an operating surgeon. The second advancing/retreating portion  12  may correspond to a transmission member. 
     The needle portion  13  is a solid body, is used for making a cut in the target site (tissue), and is capable of advancing and retreating in the second hole  113 . As illustrated in  FIGS.  2  to  4   , the needle portion  13  includes a needle portion body  131  and a flange portion  132 . The needle portion body  131  may correspond to a needle body. The flange portion  132  may correspond to a flange. 
     The needle portion body  131  is located inside the second hole  113  and is configured by a cylindrical member extending linearly along the central axis of the second hole  113 . In addition, the distal end portion of the needle portion body  131  has an outer diameter dimension that becomes smaller toward the distal end, and constitutes a cutting edge. It is noted that the needle portion  13  is provided so as to be able to advance and retreat in a direction orthogonal to the extension direction of the protrusion portion  112 . 
       FIGS.  6 A to  6 D  are diagrams illustrating an example of the shape of the flange portion  132 . Specifically,  FIGS.  6 A to  6 D  are cross-sectional views in which the connecting portion  15  and the flange portion  132  are cut at a position of line A-A illustrated in  FIG.  4   . It is noted that, in  FIGS.  6 A to  6 D , the tube  14  is illustrated by a two-dot chain line for convenience of explanation. 
     The flange portion  132  is a portion that is provided at the proximal end of the needle portion body  131  and is fixed to the distal end portion of the second advancing/retreating portion  12 . The flange portion  132  is disposed inside the connecting portion  15  and limits a moving distance in the advancing/retreating movement of the needle portion  13 . Specifically, the flange portion  132  is configured to come into contact with the proximal end of the knife body  111  when the flange portion  132  moves to the distal end side in the connecting portion  15 , and is configured to come into contact with the distal end of the tube  14  when the flange portion  132  moves to the proximal end side. It is noted that the contacting portion when the flange portion  132  moves to the distal end side is not limited to the most proximal end of the knife body  111 . A configuration in which a step such as a protrusion is provided in the vicinity of the proximal end of the knife body  111  in the radial direction of the knife body  111  and the flange portion  132  comes into contact with the step when the flange portion  132  moves to the distal end side may be adopted. Similarly, the contacting portion when the flange portion  132  moves to the proximal end side is not limited to the most distal end of the tube  14 . A configuration in which a step such as a protrusion is provided in the vicinity of the distal end of the tube  14  in the radial direction of the tube  14  and the flange portion  132  comes into contact with the step when the flange portion  132  moves to the proximal end side may be adopted. In addition, by setting the flange portion  132  to, for example, the shapes illustrated in  FIGS.  6 A to  6 D , the communication state between the passage P 1  and the second hole  113  is maintained without blocking the passage P 1 . 
     For example, as illustrated in  FIG.  6 A , the flange portion  132  protrudes from the central axis of the needle portion body  131  in the vertical and horizontal directions in  FIG.  6 A , and each protruding end portion has a +shape that is slidable on the inner peripheral surface of the connecting portion  15 . 
     In addition, for example, as illustrated in  FIG.  6 B , the flange portion  132  protrudes from the central axis of the needle portion body  131  in the horizontal directions in  FIG.  6 A , and each protruding end portion has an I shape that is slidable on the inner peripheral surface of the connecting portion  15 . 
     Furthermore, for example, as illustrated in  FIG.  6 C , the flange portion  132  is formed in a semicircular shape whose center coincides with the central axis of the needle portion body  131 . An arc portion of the outer edge of the flange portion  132  is slidable on the inner peripheral surface of the connecting portion  15 . 
     In addition, for example, as illustrated in  FIG.  6 D , the flange portion  132  may be formed in a circular shape whose center coincides with the central axis of the needle portion body  131 , and has a plurality of through holes  1321  penetrating along the central axis thereof. An arc portion of the outer edge of the flange portion  132  is slidable on the inner peripheral surface of the connecting portion  15 . 
     It is noted that the flange portion  132  may be integrally formed with the needle portion body  131 , and the flange portion  132  and the needle portion body  131  may be formed separately and may be fixed to each other by bonding or the like. In addition, the flange portion  132  may be integrally formed with the wire  12 , and the flange portion  132  and the wire  12  may be formed separately and may be fixed to each other by bonding or the like. 
     The knife  11  and the needle portion  13  described above adopt the following structures in order to avoid conduction with each other. 
     For example, insulating coating is performed on at least one of the inner peripheral surface of the second hole  113  or the front surface of the needle portion  13 . 
     In addition, for example, the needle portion  13  is made of a material having electrical insulating properties. 
     Operation of Treatment Tool for Endoscope 
     Next, the operation of the treatment tool  6  for an endoscope described above will be described. Hereinafter, for convenience of explanation, the flow of ESD will be described as an example. 
       FIGS.  7  to  10    are diagrams for describing the operation of the treatment tool  6  for an endoscope. Specifically,  FIG.  7    is a diagram for describing a marking step in ESD.  FIGS.  8  to  10    are diagrams for describing a local injection step in ESD. 
     First, an operator such as an operating surgeon inserts the endoscope insertion portion  21  into the body cavity and moves the distal end of the endoscope insertion portion  21  to the vicinity of the target site T 1  ( FIG.  7   ). 
     Next, the operator such as the operating surgeon performs a first retreating operation of pulling the first slider  82  toward the front (ring  811  side). Due to this, the treatment tool insertion portion  7  is in a state where the protrusion portion  112  is located in the large diameter portion  9211 , the proximal end of the protrusion portion  112  comes into contact with the first stepped portion  9213 , and only the protrusion portion  112  protrudes from the first hole  921  to the outside of the distal end part  92 , that is, a state (corresponding to a second mode) where the protrusion portion  112  protrudes from the first hole  921  and the knife body  111  is located in the first hole  921 . Next, the operator such as the operating surgeon performs a second retreating operation of pulling the second slider  83  toward the front (ring  811  side). Due to this, the treatment tool insertion portion  7  is in a state (corresponding to a fourth mode) where the flange portion  132  comes into contact with the distal end of the tube  14  and the distal end of the needle portion  13  is located in the second hole  113 . 
       FIG.  11    is a diagram illustrating an example of a configuration in a case where the tube  14  is not provided. Specifically,  FIG.  11    is a cross-sectional view corresponding to  FIG.  2   . 
     It is noted that, as illustrated in  FIG.  11   , in a case where the tube  14  is not provided, instead of the tube  14 , the inner diameter of the proximal end portion of the connecting portion  15  is made smaller than the maximum width of the flange portion  132 , and thus, the flange portion  132  may abut on the proximal end portion of the connecting portion  15  when the second retreating operation is performed. 
     As described above, the treatment tool insertion portion  7  is in the first state illustrated in  FIG.  2    by the first and second retreating operations on the first and second sliders  82  and  83 . An operator such as an operating surgeon inserts the treatment tool insertion portion  7  in the first state from the insertion port  223  into the pipeline inside the endoscope insertion portion  21  and protrudes the treatment tool insertion portion  7  from the distal end of the endoscope insertion portion  21 . It is noted that, even when the knife  11  slightly protrudes from the distal end part  92 , there is no problem in inserting the treatment tool insertion portion  7  in the first state from the insertion port  223  into the pipeline inside the endoscope insertion portion  21 . 
     Next, the operator such as the operating surgeon performs a marking step as shown below. 
     That is, the operator such as the operating surgeon operates the operating portion (not illustrated) such as a foot switch while maintaining the first state of the treatment tool insertion portion  7  by the first and second retreating operations on the first and second sliders  82  and  83 , and energizes the knife  11  with a high frequency current from the power source  100 . As illustrated in (a) of  FIG.  7   , the operator such as the operating surgeon presses the protrusion portion  112  against a living tissue (mucosal surface) around the target site T 1 . Due to this, the living tissue coming into contact with the protrusion portion  112  is cauterized. That is, as illustrated in (a) of  FIG.  7    or (b) of  FIG.  7   , a marking sign T 2  is formed on the cauterized portion. 
     The operator such as the operating surgeon repeats the above-described operation a plurality of times to form a number of marking signs T 2  so that the outer edge of the target site T 1  can be grasped, as illustrated in (c) of  FIG.  7   . After that, the operator such as the operating surgeon ends the energization of the knife  11  with the high frequency current from the power source  100 . 
     Next, the operator such as the operating surgeon performs a local injection step as shown below. 
     That is, the operator such as the operating surgeon performs a first advancing operation of pushing the first slider  82 . Due to this, the treatment tool insertion portion  7  is in a state (corresponding to a first mode) where the distal end of the connecting portion  15  comes into contact with the proximal end of the distal end part  92  and the knife  11  protrudes from the distal end of the sheath  9  by the maximum protrusion length. Next, the operator such as the operating surgeon performs a second advancing operation of pushing the second slider  83 . Due to this, the treatment tool insertion portion  7  is in a state (corresponding to a third mode) where the flange portion  132  comes into contact with the proximal end of the knife body  111  and the needle portion  13  protrudes from the distal end of the knife  11  by the maximum protrusion length (for example, 1 mm). 
     As described above, the treatment tool insertion portion  7  is in the second state illustrated in  FIG.  3    by the first and second advancing operations on the first and second sliders  82  and  83 . In the second state, the operator such as the operating surgeon can make a cut in the living tissue from the mucosal surface to the submucosal layer by piercing the distal end of the needle portion  13  into the living tissue around the target site T 1 . 
     That is, the operator such as the operating surgeon operates the operating portion (not illustrated) such as a foot switch while maintaining the second state of the treatment tool insertion portion  7  by the first and second advancing operations on the first and second sliders  82  and  83 , and supplies the physiological saline solution from the water supply source  200 . Due to this, the physiological saline solution supplied from the water supply source  200  is discharged from the distal end of the knife  11  after following the passage P 1  to the passage of the second hole  113 . The discharged physiological saline solution SL is injected into the submucosal layer below the target site T 1  ( FIG.  8   ). The target site T 1  (mucosal surface) bulges (floats) from other tissues such as the submucosal layer therebelow. 
     It is noted that, when injecting the physiological saline solution SL below the target site T 1 , the following two methods can be considered. 
     As illustrated in  FIG.  9   , the first method is a method of injecting the physiological saline solution SL below the target site T 1  in a state where the distal end of the needle portion  13  is inserted into the living tissue. 
     As illustrated in  FIG.  10   , the second method is a method of injecting the physiological saline solution SL below the target site T 1  in a state where the protrusion portion  112  is inserted into the living tissue together with the distal end of the needle portion  13 . 
     Next, the operator such as the operating surgeon performs an incision step as shown below. 
     That is, the operator such as the operating surgeon performs a first advancing operation on the first slider  82  and performs a second retreating operation on the second slider  83 . When the first advancing operation is performed on the first slider  82 , as described above, the treatment tool insertion portion  7  is in a state where the knife  11  protrudes from the distal end of the sheath  9  by the maximum protrusion length. In addition, when the second retreating operation is performed on the second slider  83 , as described above, the treatment tool insertion portion  7  is in a state where the distal end of the needle portion  13  is located in the second hole  113 . 
     As described above, the treatment tool insertion portion  7  is in the third state illustrated in  FIG.  4    by the first advancing operation on the first slider  82  and the second retreating operation on the second slider  83 . 
     In addition, the operator such as the operating surgeon operates the operating portion (not illustrated) such as a foot switch while maintaining the third state of the treatment tool insertion portion  7  by the first advancing operation on the first slider  82  and the second retreating operation on the second slider  83 , and energizes the knife  11  with a high frequency current from the power source  100 . The operator such as the operating surgeon moves the protrusion portion  112  along the periphery of the target site T 1  in a state where the living tissue is pierced while confirming the marking sign T 2 , and incises the entire periphery of the target site T 1 . 
     After that, while maintaining the third state, the submucosal layer including the target site T 1 , the entire periphery of which is incised, is removed by performing dissection or the like on the submucosal layer. In the third state, since the distal end of the needle portion  13  is located in the second hole  113 , the incision or dissection performance of the knife  11  is not affected. 
     ESD is completed by the above steps. 
     As described above, the needle portion  13  according to the first embodiment can advance and retreat from the position where the distal end is housed inside the knife  11  to the position where the distal end protrudes from the second hole  113 . In other words, the distal end of the needle portion  13  is housed inside the knife  11  in a retracted state. The distal end of the needle portion  13  protrudes from the distal end of the knife  11  in an extended state. 
     Hereinafter, a modification of the first embodiment will be described with reference to  FIGS.  12  and  13    by taking a treatment tool insertion portion  7 C, which is a configuration of a fourth embodiment described below, as an example. It is noted that the detailed configuration of the treatment tool insertion portion  7 C (the passage P 1 C, a first advancing/retreating portion  10 C, and a connecting portion  15 C) will be described in a fourth embodiment described below. 
     In the first embodiment, an example in which the needle portion  13  is made of a material having electrical insulating properties is shown, but the disclosure is not limited thereto. For example, the needle portion  13  may be made of an energizable material such as a metal. When the needle portion  13  is made of an energizable material, since the outer edge (outer peripheral surface) of the flange portion  132  is always in contact with the connecting portion  15 C, the needle portion  13  can be energized via the connecting portion  15 C without depending on the amount of protrusion from the knife body  111 . In addition, the method of energizing the needle portion  13  is not limited thereto. By performing insulating coating on the outer edge (outer peripheral surface) of the flange portion  132  or the inner peripheral surface of a communication hole  152 , the proximal end portion of the knife body  111  and the flange portion  132  may come into contact with each other to energize the needle portion  13  when the needle portion  13  protrudes from the knife body  111  to the maximum extent. 
     When the tissue is incised with the needle portion  13 , the distal end portion of the needle portion  13  is moved to the position protruding from the distal end of the knife  11  while retreating the distal end (protrusion portion  112 ) of the knife  11  to the position that abuts on the distal end of the sheath  9 . As illustrated in  FIG.  12   , when the distal end portion of the needle portion  13  protrudes from the distal end of the knife  11 , the flange portion  132  may abut on a portion of the knife  11 . In this state, the tissue can be incised at the distal end portion of the needle portion  13 . In addition, the puncturing of the distal end of the needle portion  13  into the tissue for local injection and the incision of the tissue may be alternately repeated. Furthermore, the incision of the tissue by the needle portion  13  and the incision of the tissue by the knife  11  may be alternately repeated. For example, after the tissue is incised with the needle portion  13 , as illustrated in  FIG.  13   , the incision of the tissue may be performed with the knife  11  in a state where the needle portion  13  is housed inside the knife  11  and the distal end of the knife  11  is located on a distal side rather than the distal end of the sheath  9  and the needle portion  13 . Here, the order of the incision by the needle portion  13  and the incision by the knife  11  may be changed as appropriate. It is noted that the incision of the tissue includes not only the incision or excision of the mucosa but also the dissection of the submucosal layer. 
     According to the first embodiment described above, the following effects are obtained. 
     In the treatment tool  6  for an endoscope according to the first embodiment, the treatment tool insertion portion  7  includes the needle portion  13  that makes a cut in the living tissue inside the body cavity, and the knife  11  that injects the physiological saline solution into the living tissue through the cut. 
     Therefore, in the treatment tool  6  for an endoscope according to the first embodiment, local injection can be performed satisfactorily by passing through the cut. 
     In particular, in the treatment tool  6  for an endoscope according to the first embodiment, in ESD, the local injection step and other steps can be performed by the single treatment tool  6  for an endoscope, without changing the treatment tool between the local injection step and other steps. Therefore, convenience can be improved. 
     In addition, in the treatment tool  6  for an endoscope according to the first embodiment, the needle portion  13  is a solid body. Therefore, compared to the configuration in which the needle portion  13  is provided with a hole for local injection, the needle portion  13  does not buckle and the life of the treatment tool insertion portion  7  can be extended. 
     In addition, in the treatment tool  6  for an endoscope according to the first embodiment, the needle portion  13  and the second advancing/retreating portion  12  are disposed in the second hole  113  and the communication hole  101 . Therefore, the first advancing/retreating portion  10 , the knife  11 , the second advancing/retreating portion  12 , and the needle portion  13  can be compactly assembled and the diameter of the treatment tool insertion portion  7  can be reduced. 
     Second Embodiment 
     Next, the second embodiment will be described. 
     In the following description, the same reference numerals are assigned to the same components as those in the first embodiment described above and detailed description thereof will be omitted or simplified. 
     The treatment tool  6  for an endoscope according to the second embodiment differs from the treatment tool  6  for an endoscope described above in the first embodiment in the configuration of the distal end portion of the treatment tool insertion portion  7 . Hereinafter, for convenience of explanation, the treatment tool insertion portion according to the second embodiment is referred to as a treatment tool insertion portion  7 A. 
       FIGS.  14  to  16    are diagrams for describing the configuration of the treatment tool insertion portion  7 A according to the second embodiment. Specifically,  FIG.  14    is a cross-sectional view corresponding to  FIG.  2    and is a diagram illustrating the treatment tool insertion portion  7 A set to a first state.  FIG.  15    is a cross-sectional view corresponding to  FIG.  3    and is a diagram illustrating the treatment tool insertion portion  7 A set to a second state.  FIG.  16    is a cross-sectional view corresponding to  FIG.  4    and is a diagram illustrating the treatment tool insertion portion  7 A set to a third state. 
     As illustrated in  FIGS.  14  to  16   , the treatment tool insertion portion  7 A differs from the treatment tool insertion portion  7  described above in the first embodiment in that the total length of the connecting portion  15  in the longitudinal direction is lengthened. Hereinafter, for convenience of explanation, a first advancing/retreating portion and a connecting portion  15  according to the second embodiment are referred to as a first advancing/retreating portion  10 A and a connecting portion  15 A, respectively. 
     In the second embodiment, the treatment tool insertion portion  7 A is in the first state shown below by the first and second retreating operations on first and second sliders  82  and  83 . 
     Specifically, due to the first retreating operation on the first slider  82 , as illustrated in  FIG.  14   , similar to the first embodiment described above, the treatment tool insertion portion  7 A is in a state where a protrusion portion  112  is located inside a large diameter portion  9211 , a proximal end of the protrusion portion  112  comes into contact with a first stepped portion  9213 , and only the protrusion portion  112  protrudes from a first hole  921  to the outside of a distal end part  92 . In addition, due to the second retreating operation on the second slider  83 , the treatment tool insertion portion  7 A is in a state where a flange portion  132  comes into contact with a distal end of a tube  14  and an entire needle portion  13  is located inside the connecting portion  15 A. 
     In addition, in the second embodiment, the treatment tool insertion portion  7 A is in the second state shown below by the first and second advancing operations on the first and second sliders  82  and  83 . 
     Specifically, due to the first advancing operation on the first slider  82 , as illustrated in  FIG.  15   , similar to the first embodiment described above, the treatment tool insertion portion  7 A is in a state where the distal end of the connecting portion  15 A comes into contact with the proximal end of the distal end part  92  and a knife  11  protrudes from a distal end of a sheath  9  by the maximum protrusion length. In addition, due to the second advancing operation on the second slider  83 , similar to the first embodiment described above, the treatment tool insertion portion  7 A is in a state where the flange portion  132  comes into contact with a proximal end of a knife body  111  and the needle portion  13  protrudes from the distal end of the knife  11  by the maximum protrusion length. 
     Furthermore, in the second embodiment, due to the first advancing operation on the first slider  82  and the second retreating operation on the second slider  83 , the treatment tool insertion portion  7 A is in the third state shown below. 
     Specifically, due to the first advancing operation on the first slider  82 , as illustrated in  FIG.  16   , as described above, the treatment tool insertion portion  7 A is in a state where the distal end of the connecting portion  15 A comes into contact with the proximal end of the distal end part  92  and the knife  11  protrudes from the distal end of the sheath  9  by the maximum protrusion length. In addition, due to the second retreating operation on the second slider  83 , as described above, the treatment tool insertion portion  7 A is in a state where the flange portion  132  comes into contact with the distal end of the tube  14  and the entire needle portion  13  is located inside the connecting portion  15 A. 
     It is noted that, since the operation of the treatment tool  6  for an endoscope according to the second embodiment is the same as the operation of the first embodiment described above, the description thereof will be omitted. 
     As described above, the needle portion  13  according to the second embodiment can advance and retreat from the position where the distal end is housed inside the first advancing/retreating portion  10 A to the position where the distal end protrudes from the second hole  113 . 
     Even when the treatment tool insertion portion  7 A according to the second embodiment described above is adopted, the same effects as those of the first embodiment described above can be obtained. 
     In addition, in the treatment tool insertion portion  7 A according to the second embodiment, the second advancing/retreating portion  12  advances and retreats the needle portion  13  from the position where the entire needle portion  13  is located on the proximal end side of the second hole  113  to the position where the distal end side of the needle portion  13  protrudes from the second hole  113  toward the distal end side. 
     Therefore, when the physiological saline solution is supplied from the water supply source  200  while the entire needle portion  13  is located inside the connecting portion  15 A by the second retreating operation on the second slider  83 , surgical site cleaning can be performed during each step of ESD, as shown below. 
     That is, in a state where the entire needle portion  13  is located inside the connecting portion  15 A, the area of the passage of the physiological saline solution flowing through the second hole  113  is large, compared to a state where the needle portion body  131  is located inside the second hole  113 . Therefore, when the physiological saline solution is supplied from the water supply source  200  while the entire needle portion  13  is located inside the connecting portion  15 A by the second retreating operation on the second slider  83 , the water pressure of the physiological saline solution discharged from the distal end of the knife  11  is relatively low. That is, the surgical site can be cleaned by supplying the physiological saline solution to the surgical site. 
     Third Embodiment 
     Next, the third embodiment will be described. 
     In the following description, the same reference numerals are assigned to the same components as those in the second embodiment described above and detailed description thereof will be omitted or simplified. 
     The treatment tool  6  for an endoscope according to the third embodiment differs from the treatment tool  6  for an endoscope described above in the second embodiment in the configuration of the distal end portion of the treatment tool insertion portion  7 A. Hereinafter, for convenience of explanation, the treatment tool insertion portion according to the third embodiment is referred to as a treatment tool insertion portion  7 B. 
       FIGS.  17  to  19    are diagrams for describing the configuration of the treatment tool insertion portion  7 B according to the third embodiment. Specifically,  FIG.  17    is a cross-sectional view corresponding to  FIG.  14    and is a diagram illustrating the treatment tool insertion portion  7 B set to a first state.  FIG.  18    is a cross-sectional view corresponding to  FIG.  15    and is a diagram illustrating the treatment tool insertion portion  7 B set to a second state.  FIG.  19    is a cross-sectional view corresponding to  FIG.  16    and is a diagram illustrating the treatment tool insertion portion  7 B set to a third state. 
     As illustrated in  FIGS.  17  to  19   , the treatment tool insertion portion  7 B differs from the treatment tool insertion portion  7 A described above in the second embodiment in that the total length of the knife  11  and the needle portion  13  in the longitudinal direction is shortened. Hereinafter, for convenience of explanation, the knife and the needle portion according to the third embodiment are referred to as a knife  11 B and a needle portion  13 B respectively. 
     In addition, as illustrated in  FIGS.  17  to  19   , the treatment tool insertion portion  7 B differs from the treatment tool insertion portion  7 A described above in the second embodiment in the shape of the distal end part  92  of the sheath  9 . Hereinafter, for convenience of explanation, the sheath and the distal end part according to the third embodiment are referred to as a sheath  9 B and a distal end part  92 B, respectively. 
     As illustrated in  FIGS.  17  to  19   , the distal end part  92 B differs from the distal end part  92  described above in the second embodiment in the shape of the first hole  921 . Hereinafter, for convenience of explanation, the first hole according to the third embodiment is referred to as a first hole  921 B. 
     As illustrated in  FIGS.  17  to  19   , the first hole  921 B includes a storage hole  9214  in addition to a large diameter portion  9211  and a small diameter portion  9212  similar to the first hole  921  described above in the second embodiment. 
     The storage hole  9214  is located on the proximal end side of the small diameter portion  9212 . The inner diameter dimension of the storage hole  9214  is set to be larger than that of the small diameter portion  9212  and slightly larger than that of the connecting portion  15 A. In the following, for convenience of explanation, a stepped portion between the small diameter portion  9212  and the storage hole  9214  is referred to as a second stepped portion  9215 . It is noted that the total length of the knife  11 B and the needle portion  13 B in the longitudinal direction is shorter than the total length of the knife  11  and the needle portion  13  described above in the second embodiment by the total length of the storage hole  9214  in the longitudinal direction. 
     In the third embodiment, the treatment tool insertion portion  7 B is in the first state shown below by the first and second retreating operations on first and second sliders  82  and  83 . 
     Specifically, due to the first retreating operation on the first slider  82 , as illustrated in  FIG.  17   , similar to the second embodiment described above, the treatment tool insertion portion  7 B is in a state where a protrusion portion  112  is located inside a large diameter portion  9211 , a proximal end of the protrusion portion  112  comes into contact with a first stepped portion  9213 , and only the protrusion portion  112  protrudes from the first hole  921 B to the outside of the distal end part  92 B. At this time, the connecting portion  15 A is located on the proximal end side of the storage hole  9214 . In addition, due to the second retreating operation on the second slider  83 , the treatment tool insertion portion  7 B is in a state where a flange portion  132  comes into contact with a distal end of a tube  14  and the entire needle portion  13 B is located inside the connecting portion  15 A. 
     In addition, in the third embodiment, the treatment tool insertion portion  7 B is in the second state shown below by the first and second advancing operations on the first and second sliders  82  and  83 . 
     Specifically, due to the first advancing operation on the first slider  82 , as illustrated in  FIG.  18   , the treatment tool insertion portion  7 B is in a state where the distal end portion of the connecting portion  15 A is located inside the storage hole  9214 , the distal end of the connecting portion  15 A comes into contact with the second stepped portion  9215 , and the knife  11 B protrudes from the distal end of the sheath  9 B by the maximum protrusion length. In addition, due to the second advancing operation on the second slider  83 , similar to the second embodiment described above, the treatment tool insertion portion  7 B is in a state where the flange portion  132  comes into contact with a proximal end of a knife body  111  and the needle portion  13 B protrudes from the distal end of the knife  11 B by the maximum protrusion length (for example, 1 mm, etc.). 
     Furthermore, in the third embodiment, due to the first advancing operation on the first slider  82  and the second retreating operation on the second slider  83 , the treatment tool insertion portion  7 B is in the third state shown below. 
     Specifically, due to the first advancing operation on the first slider  82 , as illustrated in  FIG.  19   , as described above, the treatment tool insertion portion  7 B is in a state where the distal end portion of the connecting portion  15 A is located inside the storage hole  9214 , the distal end of the connecting portion  15 A comes into contact with the second stepped portion  9215 , and the knife  11 B protrudes from the distal end of the sheath  9 B by the maximum protrusion length. In addition, due to the second retreating operation on the second slider  83 , as described above, the treatment tool insertion portion  7 B is in a state where the flange portion  132  comes into contact with the proximal end of the knife body  111  and the needle portion  13 B protrudes from the distal end of the knife  11 B by the maximum protrusion length. 
     It is noted that, since the operation of the treatment tool  6  for an endoscope according to the third embodiment is the same as the operation of the second embodiment described above, the description thereof will be omitted. 
     Even when the treatment tool insertion portion  7 B according to the third embodiment described above is adopted, the same effects as those of the second embodiment described above can be obtained. 
     In addition, in the treatment tool insertion portion  7 B according to the third embodiment, the total length of the knife  11 B and the needle portion  13 B in the longitudinal direction is short, compared to the treatment tool insertion portion  7 A described above in the second embodiment. Therefore, when the treatment tool insertion portion  7 B is inserted from the insertion port  223  into the pipeline of the endoscope insertion portion  21 , the treatment tool insertion portion  7 B can be easily bent into a shape along the pipeline, and the insertability can be improved. 
     Fourth Embodiment 
     Next, the fourth embodiment will be described. In the following description, the same reference numerals are assigned to the same components as those in the first embodiment described above and detailed description thereof will be omitted or simplified. 
     The treatment tool  6  for an endoscope according to the fourth embodiment differs from the treatment tool  6  for an endoscope described above in the first embodiment in the configuration of the distal end portion of the treatment tool insertion portion  7 . Hereinafter, for convenience of explanation, the treatment tool insertion portion according to the fourth embodiment is referred to as a treatment tool insertion portion  7 C. 
       FIGS.  20  to  22    are diagrams for describing the configuration of the treatment tool insertion portion  7 C according to the fourth embodiment. Specifically,  FIG.  20    is a cross-sectional view corresponding to  FIG.  2    and is a diagram illustrating the treatment tool insertion portion  7 C set to a first state.  FIG.  21    is a cross-sectional view corresponding to  FIG.  3    and is a diagram illustrating the treatment tool insertion portion  7 C set to a second state.  FIG.  22    is a cross-sectional view corresponding to  FIG.  4    and is a diagram illustrating the treatment tool insertion portion  7 C set to a third state. 
     In addition, as illustrated in  FIGS.  20  to  22   , the treatment tool insertion portion  7 C differs from the treatment tool insertion portion  7  described above in the first embodiment in that the inner tube  16  is omitted and differs in the passage P 1  through which the physiological saline solution flows and the shape of the connecting portion  15 . Hereinafter, for convenience of explanation, a passage, a first advancing/retreating portion, and a connecting portion according to the fourth embodiment are referred to as a passage P 1 C, a first advancing/retreating portion  10 C, and a connecting portion  15 C, respectively. 
     An inside of a sheath body  91  according to the fourth embodiment communicates with a water supply port  812 . That is, a space between the inner peripheral surface of the sheath body  91 , the outer peripheral surface of the tube  14 , and the outer peripheral surface of the connecting portion  15 C functions as the passage P 1 C, through which the physiological saline solution supplied from a water supply source  200  flows via the tube TU and the water supply port  812 . 
     As illustrated in  FIGS.  20  to  22   , a communication hole  151  that penetrates the inside and outside of the connecting portion  15 C is provided on the outer peripheral surface of the connecting portion  15 C. 
     The inside of the connecting portion  15 C corresponds to a first communication hole  152  ( FIGS.  20  to  22   ), which communicates with a second hole  113 . In addition, the communication hole  151  corresponds to a second communication hole, which communicates with the passage P 1 C and the first communication hole  152 . 
     It is noted that the operation of the treatment tool  6  for an endoscope according to the fourth embodiment differs from the first embodiment described above only in the passage of the physiological saline solution in the treatment tool insertion portion  7 C (see the arrows illustrated in  FIGS.  20  and  21   ), and thus, the description thereof is omitted. 
     Even when the treatment tool insertion portion  7 C according to the fourth embodiment described above is adopted, the same effects as those of the first embodiment described above can be obtained. 
     In addition, in the treatment tool insertion portion  7 C according to the fourth embodiment, the inner tube  16  can be omitted. Therefore, the configuration of the treatment tool insertion portion  7 C can be simplified, and the diameter of the treatment tool insertion portion  7 C can be reduced. 
     Other Embodiments 
     Although the modes for carrying out the disclosure have been described above, the disclosure should not be limited only to the first to fourth embodiments described above. 
     In the first to fourth embodiments described above, the shape of the protrusion portion  112  is not limited to the shapes described above in the first to fourth embodiments, and other shapes may also be adopted. For example, the knives  11  and  11 B may be configured by a so-called hook knife. 
     In the first to fourth embodiments described above, the knives  11  and  11 B are configured to be able to advance and retreat, but the disclosure is not limited thereto, and the knives  11  and  11 B may be unable to advance and retreat. That is, the configuration in which the knives  11  and  11 B are always in any of the following states (1) and (2) may be adopted. 
     (1) The knives  11  and  11 B are always in a state of protruding from the distal ends of the sheaths  9  and  9 B by the maximum protrusion length (for example, the state of  FIG.  2   ). 
     (2) The knives  11  and  11 B are always in a state in which only the protrusion portion  112  protrudes from the first holes  921  and  921 B to the outside of the distal end parts  92  and  92 B (for example, the state of  FIG.  3   ). 
       FIG.  23    is a diagram illustrating a first modification of the first to fourth embodiments. 
     In the first modification, as illustrated in  FIG.  23   , the shape of the second hole  113  described above in the first to fourth embodiments is different. Hereinafter, for convenience of explanation, a knife and a second hole according to the first modification are referred to as a knife  11 D and a second hole  113 D, respectively. It is noted that  FIG.  23    is a cross-sectional view in which the knife  11 D according to the first modification is cut by a cutting plane along the central axis of the knife  11 D. 
     As illustrated in  FIG.  23   , the edge portion of the distal end of the second hole  113 D is chamfered linearly in a cross-section. Since the second hole  113 D is formed as described above, when needle portions  13  and  13 B protruding from the second hole  113 D toward the distal end side are pulled toward the proximal end side, the needle portions  13  and  13 B are not caught in the edge portion of the distal end of the second hole  113 D. Therefore, a second advancing operation and a second retreating operation can be performed smoothly. 
       FIG.  24    is a diagram illustrating a second modification of the first to fourth embodiments. 
     In the second modification, as illustrated in  FIG.  24   , the shape of the second hole  113  described above in the first to fourth embodiments is different. Hereinafter, for convenience of explanation, a knife and a second hole according to the second modification are referred to as a knife  11 E and a second hole  113 E, respectively. It is noted that  FIG.  24    is a cross-sectional view in which the knife  11 E according to the second modification is cut by a cutting plane along the central axis of the knife  11 E. 
     As illustrated in  FIG.  24   , the edge portion of the distal end of the second hole  113 E is chamfered linearly in a cross-section. Since the second hole  113 E is formed as described above, when needle portions  13  and  13 B protruding from the second hole  113 E toward the distal end side are pulled toward the proximal end side, the needle portions  13  and  13 B are not caught in the edge portion of the distal end of the second hole  113 E. Therefore, a second advancing operation and a second retreating operation can be performed smoothly. 
       FIG.  25    is a diagram illustrating a third modification of the first to fourth embodiments. 
     In the third modification, as illustrated in  FIG.  25   , the shape of the protrusion portion  112  described above in the first to fourth embodiments is different. Hereinafter, for convenience of explanation, a knife and a protrusion portion according to the third modification are referred to as a knife  11 F and a protrusion portion  112 F, respectively. It is noted that  FIG.  25    is a cross-sectional view in which the knife  11 F according to the third modification is cut by a cutting plane along the central axis of the knife  11 F. 
     As illustrated in  FIG.  25   , the edge portion of the outer peripheral edge of the distal end of the protrusion portion  112 F is chamfered linearly in a cross-section. Since the protrusion portion  112 F is formed as described above, when the protrusion portion  112 F is inserted into the living tissue as described with reference to  FIG.  10   , the insertion can be performed smoothly. 
       FIG.  26    is a diagram illustrating a fourth modification of the first to fourth embodiments. 
     In the fourth modification, as illustrated in  FIG.  26   , the shape of the protrusion portion  112  described above in the first to fourth embodiments is different. Hereinafter, for convenience of explanation, a knife and a protrusion portion according to the fourth modification are referred to as a knife  11 G and a protrusion portion  112 G, respectively. It is noted that  FIG.  26    is a cross-sectional view in which the knife  11 G according to the fourth modification is cut by a cutting plane along the central axis of the knife  11 G. 
     As illustrated in  FIG.  26   , the edge portion of the outer peripheral edge of the distal end of the protrusion portion  112 G is chamfered in a curved shape in a cross-section. Since the protrusion portion  112 G is formed as described above, when the protrusion portion  112 G is inserted into the living tissue as described with reference to  FIG.  10   , the insertion can be performed smoothly. 
       FIG.  27    is a diagram illustrating a fifth modification of the first to fourth embodiments. 
     In the fifth modification, as illustrated in  FIG.  27   , the shape of the needle portions  13  and  13 B described above in the first to fourth embodiments is different. Hereinafter, for convenience of explanation, the needle portion according to the fifth embodiment is referred to as a needle portion  13 H. It is noted that  FIG.  27    is a cross-sectional view in which the needle portion  13 H according to the fifth modification is cut by a cutting plane along the central axis of the needle portion  13 H. 
     The outer diameter dimension of the distal end portion of the needle portion  13 H increases toward the distal end and gradually decreases further toward the distal end. Since the needle portion  13 H is formed as described above, similar to the first to fourth embodiments described above, when the needle portion  13 H protruding from the second hole  113  toward the distal end side are pulled toward the proximal end side, the needle portion  13 H is not caught in the edge portion of the distal end of the second hole  113 . Therefore, a second advancing operation and a second retreating operation can be performed smoothly. 
     According to the disclosure, it is possible to provide an endoscope treatment tool, and a treatment method, which are capable of performing local injection satisfactorily while maintaining the performance of tissue incision and dissection. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the disclosure 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.