Patent Publication Number: US-2023133812-A1

Title: Endoscope treatment tool

Description:
RELATED APPLICATION DATA 
     This application is based on and claims priority under 35 U.S.C. § 119 to U.S. Provisional Application No. 63/273,167, filed Oct. 29, 2021, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to an endoscope treatment tool. 
     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, blood washing, and the like are performed, as disclosed in CN 108272503 A, a method of discharging a liquid from a distal end of an electrode for incision and dissection is known. 
     SUMMARY OF DISCLOSURE 
     In some embodiments, an endoscope treatment tool includes a sheath, a knife, a connecting unit and a body. The sheath includes a first channel opened at a distal end of the sheath. The knife is inserted into the first channel, the knife having a second channel extending from a distal end of the knife to a proximal end of the knife. The connecting unit is located inside the sheath, the connecting unit including a cavity internal to the connecting unit and defining a storage path. A cross-sectional area of the cavity is larger than a cross-sectional area of the second channel. The body is disposed in the cavity. The body is translatable in the cavity between a first position and a second position. The body forms a passage and, in the first position, the passage is in communication with the second channel. 
    
    
     
       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 an operation of an endoscope treatment tool. 
         FIG.  5    is a diagram for describing an operation of an endoscope treatment tool. 
         FIG.  6    is a diagram for describing an operation of an endoscope treatment tool. 
         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 a configuration of a treatment tool insertion portion according to a second embodiment. 
         FIG.  10    is a diagram for describing a configuration of a treatment tool insertion portion according to the second embodiment. 
         FIG.  11    is a diagram for describing a configuration of a treatment tool insertion portion according to the second embodiment. 
         FIG.  12    is a diagram for describing a configuration of a treatment tool insertion portion according to the second embodiment. 
         FIG.  13    is a diagram for describing a configuration of a treatment tool insertion portion according to a third embodiment. 
         FIG.  14    is a diagram for describing a configuration of a treatment tool insertion portion according to a fourth embodiment. 
         FIG.  15    is a diagram for describing a configuration of a treatment tool insertion portion according to the fourth embodiment. 
         FIG.  16    is a diagram for describing a configuration of a treatment tool insertion portion according to the fourth embodiment. 
         FIG.  17 A  is a diagram illustrating an example of a shape of a protrusion portion. 
         FIG.  17 B  is a diagram illustrating an example of a shape of a protrusion portion. 
         FIG.  17 C  is a diagram illustrating an example of a shape of a protrusion portion. 
     
    
    
     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  and  3    are diagrams for describing the configuration of the treatment tool insertion portion  7 . Specifically,  FIG.  2    is a cross-sectional view 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.  3    is a diagram illustrating the inside of the sheath  9  at the distal end portion of the treatment tool insertion portion  7 . It is noted that, in  FIG.  3   , only the sheath  9 , a knife  11 , and a connecting portion  15  in the distal end portion of the treatment tool insertion portion  7  are cut. The connecting portion  15  may correspond to a connecting unit. 
     As illustrated in  FIGS.  1  to  3   , the treatment tool insertion portion  7  includes a sheath  9 , a second advancing/retreating portion (second tube body)  10  ( FIGS.  2  and  3   ), a knife  11  ( FIGS.  2  and  3   ), a first advancing/retreating portion (first tube body)  12  ( FIGS.  2  and  3   ), and a passage forming portion  13  ( FIGS.  2  and  3   ). The second advancing/retreating portion  10  may correspond to a second member. The first advancing/retreating portion  12  may correspond to a first member. The passage forming portion  13  may correspond to a body. 
     The sheath  9  is a portion that constitutes the outer surface of the treatment tool insertion portion  7 . As illustrated in  FIGS.  1  to  3   , 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 inserted through the distal end portion of the sheath body  91  and closes the distal end portion thereof. As illustrated in  FIGS.  2  and  3   , 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  may correspond to a first channel. 
     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 dimension on the distal end side is referred to as a large diameter portion  9211  ( FIGS.  2  and  3   ), and a portion of the first hole  921  having a small inner diameter dimension on the proximal end side is referred to as a small diameter portion  9212  ( FIGS.  2  and  3   ). 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  and  3   ). 
     The second advancing/retreating portion  10  is a member that is inserted into the sheath body  91  and advances and retreats the knife  11  along the central axis of the sheath  9 . As illustrated in  FIGS.  2  and  3   , the second advancing/retreating portion  10  includes a second advancing/retreating portion body  14  and a connecting portion  15 . 
     The second advancing/retreating portion body  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 second advancing/retreating portion body  14  is fixed to the first slider  82 . That is, the second 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 second advancing/retreating portion body  14  is electrically connected to the plug  822 . 
     The connecting portion  15  is a member that connects the second 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 of the sheath  9 . 
     As illustrated in  FIG.  2    or  FIG.  3   , the connecting portion  15  is provided with first and second fitting holes  151  and  152 , a storage hole  153 , and a pair of guide holes  154  and  155 . 
     The first fitting hole  151  corresponds to a fitting hole. The fitting hole may correspond to a fitting channel. The first fitting hole  151  is a circular hole located on the central axis of the connecting portion  15  and extending linearly from the distal end of the connecting portion  15  toward the proximal end side along the central axis thereof. The proximal end of the knife  11  is fixed to the first fitting hole  151  in a state of being inserted therethrough. 
     The second fitting hole  152  is a circular hole located on the central axis of the connecting portion  15  and extending linearly from the proximal end of the connecting portion  15  toward the distal end side along the central axis thereof. The second advancing/retreating portion body  14  is fixed to the second fitting hole  152  in a state of being inserted therethrough. That is, the connecting portion  15  advances and retreats in the sheath body  91  together with the second advancing/retreating portion body  14  according to an operation on the first slider  82  by an operator such as an operating surgeon. 
     The connecting portion  15  described above may be formed as one component, or may be configured by joining two or more components by bonding, adhering, or the like. 
     The storage hole  153  corresponds to a storage path. And the storage path may correspond to a cavity. The storage hole  153  is a circular hole located on the central axis of the connecting portion  15  and extending linearly from the distal end side of the connecting portion  15  toward the proximal end side along the central axis thereof, and communicates with the first and second fitting holes  151  and  152 . As illustrated in  FIG.  2    or  FIG.  3   , the passage forming portion  13  is housed in the storage hole  153 . 
     It is noted that the inner diameter dimensions of the second fitting hole  152  and the storage hole  153  are set to be substantially equal to each other. In addition, the inner diameter dimension of the first fitting hole  151  is set to be smaller than the inner diameter dimensions of the second fitting hole  152  and the storage hole  153 . 
     The pair of guide holes  154  and  155  are elongated holes extending in the left-and-right direction in  FIG.  2    while penetrating from the upper and lower outer peripheral surfaces to the storage hole  153  in the connecting portion  15  in  FIG.  2   . As illustrated in  FIG.  2    or  FIG.  3   , a pair of guide protrusions  130  provided in the passage forming portion  13  are inserted into the pair of guide holes  154  and  155 , respectively. 
     It is noted that the outer peripheral surface of the second advancing/retreating portion  10  described above is made of a resin material or the like and is covered with a cylindrical inner tube (not illustrated) having insulating properties and flexibility. 
     The knife  11  is made of a conductive material such as a metal and is fixed in a state where the proximal end portion thereof is inserted into the first fitting hole  151  and protrudes into the storage hole  153 . That is, the knife  11  advances and retreats in the sheath body  91  together with the second 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 second advancing/retreating portion body  14 , and the connecting portion  15 , and incises the target site in the body cavity. As illustrated in  FIG.  2    or  FIG.  3   , 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 linearly along the central axis thereof. Here, as illustrated in  FIG.  2    or  FIG.  3   , 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 outer diameter 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 . 
     As illustrated in  FIG.  2    or  FIG.  3   , 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  may correspond to a second channel. The second hole  113  communicates with the storage hole  153  by connecting the knife  11  to the second advancing/retreating portion  10 . Here, the cross-sectional area of the second hole  113  orthogonal to the central axis is smaller than the cross-sectional area of the storage hole  153  orthogonal to the central axis. 
     The first advancing/retreating portion  12  is a member that is inserted into the second advancing/retreating portion body  14  and advances and retreats the passage forming portion  13  along the central axis of the sheath  9 . The first advancing/retreating portion  12  is a cylindrical flexible coil that is made of, for example, a conductive material such as a metal, is located on the central axis of the second advancing/retreating portion body  14 , and extends linearly along the central axis thereof. The proximal end portion of the first advancing/retreating portion  12  is fixed to the second slider  83 . That is, the first advancing/retreating portion  12  advances and retreats in the second advancing/retreating portion body  14  according to an operation on the second slider  83  by an operator such as an operating surgeon. In addition, the inside of the first advancing/retreating portion  12  communicates with the water supply port  812 . Then, the inside of the first advancing/retreating portion  12  functions as a main passage P 1  ( FIG.  2   ), through which the physiological saline solution supplied from the water supply source  200  flows via the tube TU and the water supply port  812 . 
     The passage forming portion  13  is a portion that is made of a metal material or a resin material and adjusts the cross-sectional area of the passage between the main passage P 1  and the second hole  113 , and is disposed to be able to advance or retreat in the storage hole  153 . As illustrated in  FIG.  2    or  FIG.  3   , the passage forming portion  13  includes a contact portion  131  and a proximal end portion  132 . 
     The contact portion  131  is located on the central axis of the connecting portion  15  and has a cylindrical shape extending linearly along the central axis thereof. Here, the outer diameter dimension of the contact portion  131  is set to be slightly smaller than the inner diameter dimension of the storage hole  153 . 
     The proximal end portion  132  is a portion that connects the first advancing/retreating portion  12  to the passage forming portion  13 . The proximal end portion  132  is provided at the proximal end of the contact portion  131  and has a cylindrical shape that is coaxial with the central axis of the contact portion  131 . Here, the outer diameter dimension of the proximal end portion  132  is set to be smaller than the outer diameter dimension of the contact portion  131  and slightly smaller than the inner diameter dimension of the second advancing/retreating portion body  14 . 
     As illustrated in  FIG.  2    or  FIG.  3   , the passage forming portion  13  described above is provided with a third hole (passage)  133  that is located on the central axis of the contact portion  131  and penetrates from the proximal end to the distal end of the passage forming portion  13  along the central axis thereof. The third hole  133  communicates with the main passage P 1  by connecting the passage forming portion  13  to the first advancing/retreating portion  12 . In other words, the passage forming portion  13  forms the third hole  133  therein. That is, the passage forming portion  13  includes third hole  133 . 
     Here, the cross-sectional area of the third hole  133  orthogonal to the central axis is smaller than the passage area of the main passage P 1  and smaller than the cross-sectional area of the second hole  113  orthogonal to the central axis. 
     Summarizing the above, the relationship of the cross-sectional areas is the third hole  133 &lt;main passage P 1 &lt;second hole  113 &lt;storage hole  153 . It is noted that the cross-sectional areas of the main passage P 1  and the second hole  113  may be equal to each other. 
     In addition, on the outer peripheral surface of the contact portion  131 , D-cut portions  134  are provided on the left and right portions in  FIG.  3   , respectively. The D-cut portion  134  is configured by a flat surface, and has a larger gap between the inner peripheral surface of the storage hole  153  and the D-cut portion  134  than a gap between the inner peripheral surface of the storage hole  153  and the outer peripheral surface of the contact portion  131  other than the D-cut portion  134 . In other words, the passage forming portion  13  forms the gap between the inner peripheral surface of the storage hole  153  and the D-cut portion  134 . 
     In addition, on the outer peripheral surface of the contact portion  131 , the guide protrusions  130  inserted into the pair of guide holes  154 ,  155  are provided on the left and right portions in  FIGS.  2  and  3   , respectively. 
     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.  4  to  8    are diagrams for describing the operation of the treatment tool  6  for an endoscope. Specifically,  FIG.  4    is a diagram for describing a marking step in ESD.  FIG.  5    is a diagram for describing a local injection step in ESD.  FIG.  6    is a cross-sectional view corresponding to  FIG.  2    and is a diagram illustrating the treatment tool insertion portion  7  set to a first state.  FIG.  7    is a cross-sectional view corresponding to  FIG.  2    and is a diagram illustrating the treatment tool insertion portion  7  set to a second state.  FIG.  8    is a cross-sectional view corresponding to  FIG.  2    and is a diagram illustrating the treatment tool insertion portion  7  set to a third state. 
     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.  4   ). 
     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 first state ( FIG.  6   ) 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 where the protrusion portion  112  protrudes from the first hole  921  and the knife body  111  is located in the first hole  921 . 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 , and energizes the knife  11  with a high frequency current from the power source  100 . As illustrated in (a) of  FIG.  4   , the operator such as the operating surgeon presses the protrusion portion  112  against a living tissue 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.  4    or (b) of  FIG.  4   , 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.  4   . 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 first advancing operation of pushing the first slider  82 . Due to this, the treatment tool insertion portion  7  is in a state (second state) 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 where the passage forming portion  13  moved to a first position and abuts on the proximal end of the knife  11 . That is, in the first embodiment, the distal end of the contact portion  131  comes into contact with the proximal end of the knife  11  at the first position. The passage forming portion  13  covers a portion of the opening on the proximal end side in the second hole  113  (a portion of the opening on the proximal end side in the first fitting hole  151 ) by a portion other than the third hole  133 . At this time, the center of the opening on the distal end side in the third hole  133  is located coaxially with the center of the opening on the proximal end side in the second hole  113 , but it is not necessarily located coaxially. 
     It is noted that the knife  11  may be attached to the connecting portion  15  so that the proximal end of the knife  11  is located inside the first fitting hole  151 . In that case, the passage forming portion  13  may adopt a configuration in which the passage forming portion  13  comes into contact with the peripheral edge portion of the first fitting hole  151  in the connecting portion  15 , without coming into contact with the proximal end of the knife  11 . That is, the passage forming portion  13  does not necessarily come into contact with the base end of the knife  11  at the first position of the passage forming portion  13 . When coming into contact with the peripheral edge portion of the first fitting hole  151  in the connecting portion  15 , the first fitting hole  151  of the connecting portion  15  may be located between the proximal end of the knife  11  and the passage forming portion  13 . In this state, the passage forming portion  13  covers a portion of the opening on the proximal end side in the first fitting hole  151  by a portion other than the third hole  133 . 
     As described above, the treatment tool insertion portion  7  is in the second state illustrated in  FIG.  7    by the first and second advancing operations on the first and second sliders  82  and  83 . 
     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, as indicated by the arrow in  FIG.  7   , 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 from the main passage P 1  through the third hole  133  and the second hole  113 . Here, the cross-sectional area of the third hole  133  orthogonal to the central axis is smaller than the passage area of the main passage P 1 . That is, the physiological saline solution flows into the second hole  113  after the passage is narrowed down at one end by passing through the inside of the third hole  133 . Therefore, the physiological saline solution SL discharged from the distal end of the knife  11  has a relatively high water pressure and is injected below the target site T 1  by the water pressure ( FIG.  5   ). The target site T 1  floats from other tissues such as the lower submucosal layer. 
     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 . 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 sheath  9  by the maximum protrusion length. 
     In addition, the operator such as the operating surgeon operates the operating portion (not illustrated) such as a foot switch while maintaining a state in which the knife  11  protrudes from the sheath  9  by the maximum protrusion length by the first advancing operation on the first slider  82 , 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 target site T 1  is removed by performing dissection or the like on the submucosal layer including the target site T 1 , the entire periphery of which is incised. 
     ESD is completed by the above steps. It is noted that, in each step of ESD described above, when cleaning the surgical site, the operator such as the operating surgeon performs the following operations. 
     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 where the passage forming portion  13  is located at a second position that is farther from the proximal end of the knife  11  than the first position. Specifically, at the second position, it becomes a state where the proximal end portion  132  enters the second advancing/retreating portion body  14  and the proximal end of the contact portion  131  comes into contact with the distal end of the second advancing/retreating portion body  14 . That is, the storage hole  153  is located between the second hole  113  and the third hole  133 , and the treatment tool insertion portion  7  is in the third state illustrated in  FIG.  8   . It is noted that, at the second position, a gap between the proximal end portion  132  and the second advancing/retreating portion body  14  is slightly opened and communicates with a gap between the first advancing/retreating portion  12  and the second advancing/retreating portion body  14 . 
     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 second retreating operation on the second slider  83 , and supplies the physiological saline solution from the water supply source  200 . Due to this, as indicated by the arrow in  FIG.  8   , 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 from the main passage P 1  through the third hole  133 , the storage hole  153 , and the second hole  113 . Here, the cross-sectional area of the storage hole  153  orthogonal to the central axis is larger than the passage area of the main passage P 1  and the cross-sectional area of the third hole  133  orthogonal to the central axis. That is, the physiological saline solution flows into the second hole  113  after the passage is expanded at one end by passing through the inside of the storage hole  153 . At this time, the physiological saline solution flows into the storage hole  153  from the gap between the first advancing/retreating portion  12  and the second advancing/retreating portion body  14 , and is stored in the storage hole  153 . Therefore, even when water is supplied from the third hole  133 , the water is not discharged from the distal end of the knife  11  through the second hole  113  with the same water pressure. Therefore, the water pressure of the physiological saline solution discharged from the distal end of the knife  11  becomes relatively low. That is, local injection is not performed by the physiological saline solution discharged from the distal end of the knife  11 , and the physiological saline solution is supplied to the surgical site to clean the surgical site. 
     As described above, the passage cross-sectional area ratio of the second hole  113  to the third hole  133  is smaller than the passage cross-sectional area ratio of the storage hole  153  to the third hole  133 . By utilizing the relationship of the passage cross-sectional area ratio, the water pressure of the physiological saline solution discharged from the distal end of the knife  11  is adjusted. 
     It is noted that, in  FIG.  6    that illustrates the first state of the treatment tool insertion portion  7  described above in the marking step, it is assumed that the operator such as the operating surgeon performs the second retreating operation on the second slider  83 , but the disclosure is not limited thereto. The first state may be a state where the second advancing operation has been performed on the second slider  83 . 
     In addition, in  FIG.  8    that illustrates the third state of the treatment tool insertion portion  7  described above in the surgical site cleaning process, it is assumed that the operator such as the operating surgeon performs the first advancing operation on the first slider  82 , but the disclosure is not limited thereto. The third state may be a state where the first retreating operation has been performed on the first slider  82 . 
     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 passage forming portion  13  described above. A portion of the opening on the proximal end side in the second hole  113  of the knife  11  is covered with a portion of the passage forming portion  13  other than the third hole  133  when the passage forming portion  13  is located at the first position. That is, by locating the passage forming portion  13  at the first position, the water pressure of the physiological saline solution discharged from the distal end of the knife  11  can be set to be high. On the other hand, by locating the passage forming portion  13  at the second position, the water pressure of the physiological saline solution discharged from the distal end of the knife  11  can be set to be low. 
     Therefore, in the treatment tool  6  for an endoscope according to the first embodiment, the water pressure of the physiological saline solution discharged from the distal end of the knife  11  can be adjusted with a simple configuration that allows the passage forming portion  13  to move between the first position and the second position. 
     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 first advancing/retreating portion  12  and the passage forming portion  13  are disposed in the second advancing/retreating portion  10 . Therefore, the first advancing/retreating portion  12 , the second advancing/retreating portion  10 , and the passage forming portion  13  can be compactly assembled and the diameter of the treatment tool insertion portion  7  can be reduced. It is noted that, since the first advancing/retreating portion  12  and the second advancing/retreating portion  10  can be independently operated to be able to advance and retreat, only the water pressure can be adjusted according to the purpose such as local injection or cleaning while the knife  11  is positioned. 
     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.  9  to  12    are diagrams for describing the configuration of the treatment tool insertion portion  7 A according to the second embodiment. Specifically,  FIG.  9    is a cross-sectional view corresponding to  FIG.  7    and is a diagram illustrating the treatment tool insertion portion  7 A set to a second state.  FIG.  10    is a diagram illustrating the inside of the sheath  9  at the distal end portion of the treatment tool insertion portion  7 A set to the second state. It is noted that, in  FIG.  10   , only the sheath body  91  and the connecting portion  15  in the distal end portion of the treatment tool insertion portion  7 A are cut. In addition, in  FIG.  10   , for convenience of explanation, the knife  11  is illustrated by an alternate long and short dash line.  FIG.  11    is a cross-sectional view corresponding to  FIG.  8    and is a diagram illustrating the treatment tool insertion portion  7 A set to a third state. Specifically  FIG.  12    is a diagram, when viewed from the distal end side, illustrating a cross-section obtained when the distal end portion of the treatment tool insertion portion  7 A is cut at the position passing through the knife  11  by a plane orthogonal to the central axis of the treatment tool insertion portion  7 A. It is noted that, in  FIG.  12   , for convenience of explanation, the illustration of the sheath  9  and the connecting portion  15  is omitted. 
     As illustrated in  FIGS.  9  to  11   , the treatment tool insertion portion  7 A differs from the treatment tool insertion portion  7  described above in the first embodiment in the shapes of the second advancing/retreating portion  10  and the passage forming portion  13 . Hereinafter, for convenience of explanation, a second advancing/retreating portion and a passage forming portion according to the second embodiment are referred to as a second advancing/retreating portion  10 A and a passage forming portion  13 A, respectively. 
     As illustrated in  FIGS.  9  to  11   , the second advancing/retreating portion  10 A differs from the second advancing/retreating portion  10  described above in the first embodiment in the shape of the second advancing/retreating portion body  14 . Hereinafter, for convenience of explanation, the second advancing/retreating portion body according to the second embodiment is referred to as a second advancing/retreating portion body  14 A. 
     In the second embodiment, the water supply port  812  communicates with not the first advancing/retreating portion  12  but the second advancing/retreating portion body  14 A. A space between the inner peripheral surface of the second advancing/retreating portion body  14 A and the outer peripheral surface of the first advancing/retreating portion  12  functions as a main passage P 1 A ( FIGS.  9  to  11   ), through which the physiological saline solution supplied from the water supply source  200  flows via the tube TU and the water supply port  812 . 
     In addition, as illustrated in  FIGS.  9  to  11   , a first notch portion  141  is provided at the distal end portion of the second advancing/retreating portion body  14 A. 
     The first notch portion  141  corresponds to a communication hole, which is notched from the distal end of the second advancing/retreating portion body  14 A toward the proximal end side and communicates the main passage P 1 A with the storage hole  153 . The communication hole may correspond to a communication channel. 
     It is noted that the outer peripheral surface of the second advancing/retreating portion  10 A described above is covered with an inner tube (not illustrated) as in the first embodiment described above. 
     In the passage forming portion  13 A, the third hole  133  is not provided in the passage forming portion  13 A described above in the first embodiment. In addition, as illustrated in  FIGS.  9  to  11   , a second notch portion  135  is provided in the passage forming portion  13 A, and a passage is formed by the second notch portion  135 . In other words, the passage forming portion  13  forms the second notch portion  135  therein. That is, the passage forming portion  13  includes the second notch portion  135 . 
     The outer peripheral surface of the passage forming portion  13 A includes a pair of D-cut portions  134  formed from the distal end to the proximal end, and a flat surface is formed. It is noted that the surface does not necessarily have to be a flat surface, and may be a concave surface extending in a concave shape along a longitudinal axis. In addition, the outer peripheral surface of the cross-section of the passage forming portion  13 A may be an ellipse or an oval. Even when the outer peripheral surface of the cross-section of the passage forming portion  13 A has a perfect circular shape, the outer diameter may be to the extent that a gap is formed between the passage forming portion  13 A and a connecting portion  15 A. With this structure, a passage is defined by a gap formed between the outer peripheral surface of the passage forming portion  13 A and the inner peripheral surface of the connecting portion  15 . 
     The second notch portion  135  is a groove formed from the pair of D-cut portions  134  to the distal end surface of the contact portion  131  along the surface of the contact portion  131 . 
     It is noted that the operation of the treatment tool  6  for an endoscope according to the second embodiment differs from the first embodiment described above only in the passage of the physiological saline solution in the treatment tool insertion portion  7 A (see the arrows illustrated in  FIGS.  9  and  11   ). 
     Specifically, in the local injection step, when the operator such as the operating surgeon performs the first and second advancing operations on the first and second sliders  82  and  83 , the treatment tool insertion portion  7 A is in a second state ( FIG.  9   ) where the passage forming portion  13 A is located at the first position. At the first position, as illustrated in  FIG.  12   , a portion of the second notch portion  135  is located in the second hole  113  when viewed along the central axis of the second hole  113 . That is, the passage forming portion  13 A covers a portion of the opening on the proximal end side in the second hole  113  by a portion other than the second notch portion  135 . As indicated by the arrows in  FIG.  9   , the physiological saline solution supplied from the water supply source  200  passes from the main passage PIA through the storage hole  153 , the D-cut portion  134 , and the second notch portion  135 , via the first notch portion  141 , follows the passage of the second hole  113  from the second notch portion  135 , and is then discharged from the distal end of the knife  11 . 
     Specifically, in the surgical site cleaning, when the operator such as the operating surgeon performs the second retreating operations on the second slider  83 , the treatment tool insertion portion  7 A is in a third state ( FIG.  11   ) where the passage forming portion  13 A is located at the second position. As indicated by the arrows in  FIG.  11   , the physiological saline solution supplied from the water supply source  200  passes from the main passage P 1 A through the D-cut portion  134 , the second notch portion  135 , and the storage hole  153  via the first notch portion  141 , follows the passage of the second hole  113  from the storage hole  153 , and is then discharged from the distal end of the knife  11 . 
     Here, the passage cross-sectional area ratio of the second hole  113  to the gap (passage) between the passage forming portion  13 A and the inner peripheral surface of the connecting portion  15  is smaller than the passage cross-sectional area ratio of the storage hole  153  to the gap (passage) between the passage forming portion  13 A and the inner peripheral surface of the connecting portion  15 . Therefore, the water pressure of the physiological saline solution discharged from the distal end of the knife  11  in the local injection step is higher than the water pressure of the physiological saline solution discharged from the distal end of the knife  11  in the surgical site cleaning. 
     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. 
     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. 
       FIG.  13    is a diagram for describing the configuration of the treatment tool insertion portion  7 B according to the third embodiment. Specifically,  FIG.  13    is a diagram corresponding to  FIG.  12   . 
     As illustrated in  FIG.  13   , the treatment tool insertion portion  7 B differs from the treatment tool insertion portion  7 A described above in the second embodiment in the shapes of the passage forming portion  13 . Hereinafter, for convenience of explanation, the passage forming portion according to the third embodiment is referred to as a passage forming portion  13 B. 
     In the passage forming portion  13 B, as illustrated in  FIG.  13   , the third hole  133  described above in the first embodiment is provided to the treatment tool insertion portion  7 A described above in the second embodiment. 
     In the third embodiment, the water supply port  812  communicates with both the inside of the first advancing/retreating portion  12  and the inside of the second advancing/retreating portion body  14 A. That is, the inside of the first advancing/retreating portion  12  and the space between the inner peripheral surface of the second advancing/retreating portion body  14 A and the outer peripheral surface of the first advancing/retreating portion  12  function as the main passage, through which the physiological saline solution supplied from the water supply source  200  flows via the tube TU and the water supply port  812 . The main passage is a combination of the main passage P 1  described above in the first embodiment and the main passage P 1 A described above in the second embodiment. 
     It is noted that the operation of the treatment tool  6  for an endoscope according to the third embodiment differs from the first and second embodiments described above only in the passage of the physiological saline solution in the treatment tool insertion portion  7 B. 
     Specifically, in the third embodiment, the passage of the physiological saline solution in the treatment tool insertion portion  7 B is a combination of the passage described above in the first embodiment and the passage described above in the second embodiment. 
     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 first and second embodiments described above can be obtained. 
     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.  14  to  16    are diagrams for describing the configuration of the treatment tool insertion portion  7 C according to the fourth embodiment. Specifically,  FIG.  14    is a cross-sectional view corresponding to  FIG.  2    and is a diagram illustrating the treatment tool insertion portion  7 C set to a fourth state.  FIG.  15    is a cross-sectional view corresponding to  FIG.  2    and is a diagram illustrating the treatment tool insertion portion  7 C set to a fifth state.  FIG.  16    is a cross-sectional view corresponding to  FIG.  2    and is a diagram illustrating the treatment tool insertion portion  7 C set to a sixth state. 
     In the treatment tool insertion portion  7 C, as illustrated in  FIGS.  14  to  16   , the first advancing/retreating portion  12  is omitted with respect to the treatment tool insertion portion  7  described above in the first embodiment. In the fourth embodiment, although the specific illustration is omitted, the second slider  83  is also omitted as the first advancing/retreating portion  12  is omitted. In addition, as the first advancing/retreating portion  12  is omitted, the main passage becomes the inside of the second advancing/retreating portion body  14 . 
     In addition, the treatment tool insertion portion  7 C differs from the treatment tool insertion portion  7  described above in the first embodiment in the second advancing/retreating portion  10 . Hereinafter, for convenience of explanation, the second advancing/retreating portion according to the fourth embodiment is referred to as a second advancing/retreating portion  10 C. 
     The second advancing/retreating portion  10 C differs from the second advancing/retreating portion  10  described above in the first embodiment in the relationship between the second advancing/retreating portion body  14  and the connecting portion  15 . 
     Specifically, in the fourth embodiment, the second advancing/retreating portion body  14  is configured to be able to advance and retreat in the second fitting hole  152  and the storage hole  153  along the central axis of the connecting portion  15 . In addition, the proximal end of the contact portion  131  comes into contact with the distal end of the second advancing/retreating portion body  14 , and the passage forming portion  13  is fixed in a state where the proximal end portion  132  is inserted into the second advancing/retreating portion body  14 . That is, the passage forming portion  13  advances and retreats in the storage hole  153  together with the second advancing/retreating portion body  14  according to the operation on the first slider  82  by the operator such as the operating surgeon. 
     It is noted that the outer peripheral surface of the second advancing/retreating portion  10 C described above is covered with an inner tube (not illustrated) as in the first embodiment described above. 
     Furthermore, in the treatment tool insertion portion  7 C, as illustrated in  FIGS.  14  to  16   , an urging member  16  is disposed in the storage hole  153 . 
     In the fourth embodiment, as illustrated in  FIGS.  14  to  16   , the urging member  16  is configured by a coil spring. One end of the urging member  16  is in contact with or fixed to the distal end of the contact portion  131 , and the other end of the urging member  16  is in contact with or fixed to the peripheral edge portion of the first fitting hole  151  in the connecting portion  15 . The urging member  16  urges the passage forming portion  13  toward the second position. 
     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 operation on the treatment tool operating portion  8  by the operator such as the operating surgeon. 
     Specifically, in the marking step, the operator such as the operating surgeon performs a first retreating operation on the first slider  82 . Due to this, the knife  11  is pulled toward the proximal end side by the second advancing/retreating portion body  14 , the passage forming portion  13 , and the connecting portion  15 . The treatment tool insertion portion  7 C is in a state where the protrusion portion  112  is located inside 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 . In addition, the passage forming portion  13  moves toward the proximal end side together with the second advancing/retreating portion body  14  in the storage hole  153 , and is located at a second position away from the proximal end of the knife  11 . 
     As described above, the treatment tool insertion portion  7 C is in the fourth state illustrated in  FIG.  14    by the first retreating operation on the first slider  82 . The operator such as the operating surgeon operates the operating portion (not illustrated) such as a foot switch while maintaining the fourth state of the treatment tool insertion portion  7 C by the first retreating operation on the first slider  82 , and energizes the knife  11  with a high frequency current from the power source  100 . After that, the operator such as the operating surgeon forms the marking sign T 2  in the same manner as in the first embodiment described above. 
     In addition, in the local injection step, the operator such as the operating surgeon performs a third protruding operation of pushing the first slider  82 . 
     When the first slider  82  is lightly pushed in the third protruding operation, the treatment tool insertion portion  7 C is in the fifth state illustrated in  FIG.  15   . The fifth state is a state 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. Here, the passage forming portion  13  maintains the state of being located at the second position by the urging force of the urging member  16 . 
     In addition, when the first slider  82  is strongly pushed in the third protruding operation, the treatment tool insertion portion  7 C changes from the fifth state illustrated in  FIG.  15    to the sixth state illustrated in  FIG.  16   . In the sixth state, the passage forming portion  13  moves toward the distal end side in the storage hole  153  against the urging force of the urging member  16  together with the second advancing/retreating portion body  14  and is in a state of being located at the first position close to the proximal end of the knife  11 . In the fourth embodiment, the distal end of the contact portion  131  comes into contact with the proximal end of the knife  11  at the first position. The passage forming portion  13  covers a portion of the opening on the proximal end side in the second hole  113  by a portion other than the third hole  133 . In the sixth state, the passage is in communication with the second hole  113  via the urging member  16  in the first position. In this embodiment, the passage may be formed by the gap. The gap is formed between the storage hole  153  and the passage forming portion  13 . 
     The operator such as the operating surgeon operates the operating portion (not illustrated) such as a foot switch while maintaining the sixth state of the treatment tool insertion portion  7 C by a third protruding operation on the first slider  82 , and supplies the physiological saline solution from the water supply source  200 . Due to this, the physiological saline solution is discharged from the distal end of the knife  11 , and the physiological saline solution is injected below the target site T 1  in the same manner as in the first embodiment described above. 
     Furthermore, in the incision step, the operator such as the operating surgeon operates the operating portion (not illustrated) such as a foot switch while maintaining the fifth state ( FIG.  15   ) or the sixth state ( FIG.  16   ) of the treatment tool insertion portion  7 C by the third protruding operation on the first slider  82 , and energizes the knife  11  with a high frequency current from the power source  100 . After that, the operator such as the operating surgeon makes an incision on the entire periphery of the target site T 1  while confirming the marking sign T 2 , as in the first embodiment described above. 
     In addition, in the surgical site cleaning, the operator such as the operating surgeon sets the treatment tool insertion portion  7 C to the fourth state ( FIG.  14   ) by the first retreating operation on the first slider  82 . Alternatively, the operator such as the operating surgeon sets the treatment tool insertion portion  7 C to the fifth state ( FIG.  15   ) by the third protruding operation on the first slider  82 . After that, the operator such as the operating surgeon operates the operating portion (not illustrated) such as a foot switch to supply the physiological saline solution from the water supply source  200 . Due to this, the physiological saline solution is discharged from the distal end of the knife  11 , and the surgical site is cleaned in the same manner as in the first embodiment described above. 
     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, since the first advancing/retreating portion  12  and the second slider  83  can be omitted, the configuration of the treatment tool  6  for an endoscope can be simplified. 
     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. 
       FIGS.  17 A to  17 C  are diagrams illustrating an example of the shape of the protrusion portion  112 . 
     Specifically, as illustrated in  FIGS.  17 A to  17 C , the protrusion portion  112  may have a flange shape such as a hemispherical shape ( FIG.  17 A ) or a triangular shape ( FIG.  17 B ), but the disclosure is not limited to the flange shape, and the protrusion portion  112  may have a hook shape ( FIG.  17 C ). 
     In the first to fourth embodiments described above, the knife  11  is configured to be able to advance and retreat, but the disclosure is not limited thereto, and the knife  11  may be unable to advance and retreat. That is, the configuration in which the knife  11  is always in any of the following states (1) and (2) may be adopted. 
     (1) The knife  11  is always in a state of protruding from the distal end of the sheath  9  by the maximum protrusion length (for example, the states of  FIGS.  7  and  8   ). 
     (2) The knife  11  is always in a state in which only the protrusion portion  112  protrudes from the first hole  921  to the outside of the distal end part  92  (for example, the state of  FIG.  6   ). 
     An endoscope treatment tool according to the disclosure can adjust a pressure of a discharged fluid with a simple configuration. 
     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.