Patent Description:
In the related art, an endoscopic clip device is inserted into a body by using an endoscope device to ligate a treatment target area as a treatment instrument for closing a wound occurred in a living body tissue and performing hemostasis treatment. For example, in Patent Document <NUM>, it is disclosed that a ligation device has a clip unit with a plurality of arms that are coupled to an operation wire and the clip unit is displaced by retracting the clip unit into a tube member fixed to a distal end of a coil sheath such that distal ends of each arm approaches each other to close a defective area of a mucous membrane as the treatment target area. According to the ligation device disclosed in Patent Document <NUM>, after the distal ends of the arms are closed, coupling of the operation wire and the arms, and connection of the tube member and the coil sheath are released. As a result, the clip unit is spaced from the ligation device and is placed on the tissue (mucous membrane).

As a further example, Patent Document <NUM> discloses a ligation apparatus for ligaturing a living tissue in a body cavity by a clip, the apparatus including a clip main body, formed by pressing a pressing member, a pair of arm portions for grasping the living tissue, and an operation wire for operating a clip. A pair of bridge portions are bridged at a distal end portion of the pressing member in a diametrical direction so as to cross a distal end opening formed at the distal end portion of the pressing member. Accordingly, the distal end opening is divided into two openings, through which a respective one of the arm portions is slidably inserted. The bridge portions may be formed by inwardly bending elongated plate-shaped pieces projecting in a direction parallel to the central axis of the pressing member.

When a tissue such as a mucous membrane is ligated by using the clip of the ligation device in the related art, it is necessary to close the arms of the clip while maintaining a state where the arms are open and in contact with the mucous membrane in the vicinity of the treatment target area. Therefore, an operator presses the distal end of the clip against the tissue in a state where the arms are open, and uses a pressing force so as to fix a state where the arms are in contact with the treatment target area to cause the clip to grasp the tissue. In a case where the tissue is ligated by using the ligation device disclosed in Patent Document <NUM>, the arms are pulled into the tube member in order to pinch the tissue. Accordingly, the arms move in a retraction direction relatively to the tissue. In order to grasp the mucous membrane in a desired state, it is necessary to maintain a state where the tissue is pressed by the arms even during a process where the arms is retracted relatively to the tissue as described above. Accordingly, in order to grasp the mucous membrane in the desired state, it is necessary to continuously perform an operation to press the clip against the tissue while the clip is retracted relatively to the tissue.

In a case where the tissue is ligated by using the ligation device disclosed in Patent Document <NUM>, if the plurality of arms can be pressed against the mucous membrane in a direction in which an axis of the tube member is orthogonal to a plane formed by the mucous membrane to be ligated, the tissue can be evenly pressed by the distal end of the plurality of arms, the tissue ligation can be relatively smoothly performed. However, the axis of the tube member and the plane formed by the mucous membrane are not always orthogonal to each other. For example, in a case where the mucous membrane is ligated inside a gastrointestinal tract such as a large intestine and the like, an endoscope insertion portion is inserted along a lumen such that it is difficult to press the plurality of arms against the mucous membrane in the direction orthogonal to the mucous membrane to be ligated. In a case where the plurality of arms are pressed against the mucous membrane in a direction oblique to the mucous membrane, difference is generated between the pressing forces applied to the mucous membrane by the respective arms. As a result, the arm pressed by a relatively stronger pressing force slips on the mucous membrane, and thus, a position of the arm cannot be fixed. Since there is an arm pressed by the relatively weaker pressing force, it is not possible to obtain a sufficient pressing force to draw the mucous membrane by pinching the mucous membrane between the plurality of arms such that the treatment target area cannot be caught therebetween in some cases.

In view of the above-described circumstances, the present invention aims to provide an endoscopic treatment instrument which can properly perform tissue ligation through an endoscope.

According to a first aspect of the present invention, an endoscopic treatment instrument includes a pressing tube that has an insertion lumen; a clip main body that has a first arm, the first arm being inserted into the insertion lumen such that the first arm protrudes from a distal end of the pressing tube; a second arm that is fixed to the pressing tube to protrude to a distal end side of the pressing tube; and an operation wire that is connected to the clip main body and configured to advance and retract the clip main body with respect to the pressing tube. The first arm approaches the second arm while being moved to a proximal end side of the pressing tube by being pulled by the operation wire. In an initial state before the clip main body is pulled by the operation wire, a position of a distal end of the first arm in a longitudinal axis direction of the pressing tube is more distal than a position of a distal end of the second arm. The distal end of the first arm is configured to approach the distal end portion of the second arm when the clip main body is pulled to the proximal end side of the pressing tube. The second arm extends more distally than the distal end side oft he pressing tube.

According to a second aspect of the present invention, in the endoscopic treatment instrument according to the above-described first aspect, the first arm may be disposed so as to incline with respect to a longitudinal axis of the pressing tube when the first arm protrudes from the distal end portion of the pressing tube, and the second arm may be fixed to the pressing tube at an angle which is substantially parallel to the longitudinal axis.

According to a third aspect of the present invention, in the endoscopic treatment instrument according to the above-described first aspect or second aspect, the first arm may be configured to be elastically deformable and have a shape inclined in a direction in which the distal end portion of the first arm is spaced from the longitudinal axis of the pressing tube, in a state where the first arm protrudes from the distal end portion of the pressing tube, and the first arm may be pressed by the pressing tube to be elastically deformed when the clip main body is pulled to the proximal end side of the pressing tube.

According to a fourth aspect of the present invention, in the endoscopic treatment instrument according to the above-described second aspect, the clip main body may have a connection portion to be connected to the operation wire on the proximal end side of the clip main body, and a connection between the operation wire and the clip main body may be released as the connection portion protrudes from the proximal end of the pressing tube, while the clip main body is pulled toward the proximal end side of the pressing tube.

According to the above-described respective aspects, it is possible to provide an endoscopic treatment instrument which can properly perform tissue ligation on a gastrointestinal tract through an endoscope.

An endoscopic treatment instrument (hereinafter, simply referred to as a "treatment instrument") according to a first embodiment of the present invention will be described. <FIG> is an overall view showing a treatment instrument <NUM> according to the present embodiment. <FIG> is a sectional view showing a distal end portion of the treatment instrument <NUM>. <FIG> is a view when the distal end portion of the treatment instrument <NUM> is viewed in a direction indicated by an arrow A in <FIG>. <FIG> is a view when the distal end portion of the treatment instrument is viewed in a direction indicated by an arrow B in <FIG>. In <FIG> and <FIG>, a sheath <NUM> is shown using a cross section on a plane passing through a central axis of a pressing tube <NUM>.

As shown in <FIG> and <FIG>, the treatment instrument <NUM> according to the present embodiment has a clip unit <NUM>, an operation wire <NUM>, and the sheath <NUM>. The clip unit <NUM> includes a clip main body <NUM>, the pressing tube <NUM>, and a second arm <NUM>, and is mounted at a distal end of the sheath <NUM> into which the operation wire <NUM> is inserted. The clip main body <NUM>, the second arm <NUM>, the operation wire <NUM>, and the sheath <NUM> are disposed along a central axis (longitudinal axis) L in a longitudinal direction of the pressing tube <NUM>.

As shown in <FIG>, for example, the clip main body <NUM> is formed by performing a bending process on a thin and long metal plate. For example, a material of the clip main body <NUM> includes stainless steel, a cobalt chromium alloy, or a titanium alloy. The clip main body <NUM> has a bending portion <NUM> disposed on a proximal end side, and a first arm <NUM> disposed so as to extend to a distal end side from the bending portion <NUM>.

The bending portion <NUM> is formed in an arc shape by bending the clip main body <NUM> in a plate thickness direction. Both end portions of the bending portion <NUM> extend to the distal end side so as to be substantially parallel to each other, thereby forming a first extension portion <NUM> and a second extension portion <NUM>. The first arm <NUM> extending in a distal end direction is disposed on the distal end side of the first extension portion <NUM>. The distal end of the second extension portion <NUM> is disposed in a second tubular portion <NUM> that is described later. According to the present embodiment, in the clip main body <NUM>, a single stainless steel plate is subjected to the bending process to form the bending portion <NUM>, the first extension portion <NUM>, the second extension portion <NUM>, and the first arm <NUM>.

The first arm <NUM> is disposed so as to extend from the distal end of the first extension portion <NUM> to the distal end portion of the clip main body <NUM>. The distal end of the first arm <NUM> protrudes more distally than the distal end of the second extension portion <NUM>. That is, a portion close to one end portion in the longitudinal direction of the thin and long stainless steel plate is subjected to the bending process to form the bending portion <NUM>. Hereinafter, a surface located on an inner side of the bending portion <NUM> in the clip main body <NUM> is referred to as an inner surface, and a surface located on an outer side of the bending portion <NUM> is referred to as an outer surface.

The first arm <NUM> has a first portion <NUM>, a second portion <NUM>, and a third portion <NUM>. The first portion <NUM> is formed so as to extend to the distal end along an extending direction of the first extension portion <NUM>. The second portion <NUM> is subjected to the bending process so as to be bent to the outer surface side from the first portion <NUM>. As shown in <FIG> and <FIG>, the third portion <NUM> is subjected to the bending process so as to be bent to the inner surface side in the distal end portion of the second portion <NUM> and the third portion <NUM> is disposed to have a wider plate width than that of the second portion <NUM>.

A serrated projection <NUM> which projects in such a way that both sides of the clip main body <NUM> are widened in a plate width direction is formed between the first extension portion <NUM> and the first portion <NUM>. The plate width in the projection <NUM> is set to a width substantially the same as or slightly wider than an opening width of a third insertion lumen <NUM>. As shown in <FIG>, in the serrated shape of the projection <NUM>, the distal end side extends in a direction orthogonal to a center line C in the plate width direction of the clip main body <NUM>, and has a shape whose proximal end side inclines. The serrated projection <NUM> may also be similarly disposed in the second extension portion <NUM>.

As shown in <FIG>, the second portion <NUM> is bent to the outer surface side, and the second portion <NUM> is bent like a bow in a separating direction in which the second portion inclines with respect to a longitudinal axis L of the pressing tube <NUM> in a state where the second portion <NUM> protrudes from the pressing tube <NUM>.

The first arm <NUM> further has a fourth portion (distal end portion) <NUM> which is folded to the inner surface side in the distal end portion of the third portion <NUM>. The fourth portion <NUM> is bent in the distal end of the third portion <NUM>, and inclines with respect to the inner surface side. As shown in <FIG>, in the fourth portion <NUM>, the plate width is gradually narrowed from the proximal end side toward the distal end side, and the distal end portion is formed in a serrated shape.

The plate width of the clip main body <NUM> is equal in the bending portion <NUM>, the first extension portion <NUM>, the second extension portion <NUM>, and the first portion <NUM>. The third portion <NUM> is further widened on the proximal end side compared to the second portion <NUM>, and has a wider plate width than an opening width of a first insertion lumen <NUM> of a first tubular portion <NUM> of the pressing tube <NUM> that is described later. The third portion <NUM> is formed so that the plate width is gradually narrowed toward the distal end side. According to the present embodiment, the second portion <NUM> has the wider plate width than that of the first portion <NUM>, and the second portion <NUM> may have substantially the same plate width than that of the first portion <NUM>.

The first arm <NUM> is formed to the above- described shape by being bent in advance, and the first arm <NUM> is formed to be capable of elastically deforming if an external force is applied and capable of restoring to the above-described bent shape in a state where the external force is not applied thereto The clip main body <NUM> is inserted into the first insertion lumen <NUM> so that the first arm <NUM> protrudes from the distal end of the pressing tube <NUM>. The bending portion <NUM> of the clip main body <NUM> is engaged to a coupling member that is described later.

The pressing tube <NUM> has the first tubular portion <NUM> disposed on the distal end side, and the second tubular portion <NUM> disposed on the proximal end side. Insertion lumens <NUM> and <NUM> are formed therein. <FIG> is a perspective view of the first tubular portion <NUM>. The first tubular portion <NUM> is a substantially tubular member having a smaller diameter than an opening diameter of the lumen of the sheath <NUM>.

In the second tubular portion <NUM>, the second insertion lumen <NUM> is formed on the distal end side, and the third insertion lumen <NUM> is formed on the proximal end side. Both of these communicate with each other from the distal end to the proximal end. The second insertion lumen <NUM> and the third insertion lumen <NUM> have a dimension which enables a distal end portion of a coupling member <NUM> to move forward or rearward.

The second tubular portion <NUM> has a main body 32a and protruding portions 32c. The main body 32a has a slightly smaller outer diameter than the opening diameter of the lumen of the sheath <NUM>. The protruding portions 32c are disposed in an outer peripheral surface 32b of the main body 32a. As shown in <FIG> and <FIG>, the protruding portions 32c are disposed at two locations on the outer peripheral surface 32b of the second tubular portion <NUM> so that a triangular flat plate protrudes outward in a radial direction. The two protruding portions 32c are separately disposed at an interval of <NUM> degrees in a circumferential direction of the second tubular portion <NUM>. The protruding portions 32c are disposed so as to be elastically deformable inward of the second tubular portion <NUM> if a pressing force is applied thereto from the outside in the radial direction of the second tubular portion <NUM>.

In the pressing tube <NUM>, the proximal end portion of the first tubular portion <NUM> is fitted and fixed to the distal end portion of the second tubular portion <NUM>. The first insertion lumen <NUM> formed in the first tubular portion <NUM> and the second insertion lumen <NUM> formed inside the second tubular portion <NUM> have substantially the same opening diameter, and communicate with each other. The clip main body <NUM> is advanceably and retractably inserted into the first insertion lumen <NUM> and the second insertion lumen <NUM>. For example, the pressing tube <NUM> is manufactured by using a metal material such as stainless steel, a titanium alloy (Ti-6AL-4V), and a cobalt chromium alloy, or a rigid resin material having moderate elasticity such as polyphthalamide (PPA) and polyamide (PA).

The pressing tube <NUM> is disposed to be advanceable and retractable with respect to the sheath <NUM>, and attachable to or detachable from the sheath <NUM>. An outer peripheral diameter of the proximal end portion of the second tubular portion <NUM> is formed to be slightly smaller than the opening diameter of the lumen of the sheath <NUM>. As shown in <FIG>, the pressing tube <NUM> can be accommodated inside the sheath <NUM> in such a way that the protruding portion 32c is pressed inward of the second tubular portion <NUM>. As shown in <FIG>, when the pressing tube <NUM> protrudes from the distal end of the sheath <NUM>, the pressing tube <NUM> is inserted into the sheath <NUM> in a state where the outer peripheral surface of the proximal end portion of the second tubular portion <NUM> moves close to an inner wall of the lumen of the sheath <NUM>, and the pressing tube <NUM> is connected to the sheath <NUM> in a state where each proximal end surface of the two protruding portions 32c is in contact with the distal end portion of the sheath <NUM>,. In a state where the pressing tube <NUM> is connected to the sheath <NUM>, the proximal end surface of the protruding portion is in contact with the distal end portion of the sheath <NUM> such that the pressing tube <NUM> is connected to the sheath <NUM> so as to be immovable relative to the proximal end side.

As shown in <FIG>, the second arm <NUM> protrudes from and fixed to the distal end portion of the pressing tube <NUM> such that the second arm <NUM> extends more distally than the distal end side of the pressing tube <NUM>. The second arm <NUM> protrudes from one portion of an opening edge <NUM> of the distal end of the first tubular portion <NUM>, and extends along a direction of the longitudinal axis L of the first tubular portion <NUM>. The second arm <NUM> according to the present embodiment is formed integrally with the first tubular portion <NUM>.

In a state where the first arm <NUM> protrudes to the distal end side of the first tubular portion <NUM> (initial state), as shown in <FIG>, a position P1 of the fourth portion <NUM> in the direction of the longitudinal axis L of the pressing tube <NUM> is located more distal than a position P2 of a distal end portion <NUM> of the second arm <NUM>. That is, a protruding length of the first arm <NUM> from the opening edge <NUM> (distal end portion of thee pressing tube) of the first tubular portion <NUM> is longer than a protruding length of the second arm <NUM> from the opening edge <NUM> of the first tubular portion <NUM>. On the other hand, a configuration is adopted in which the first arm <NUM> is elastically deformed after coming into contact with the pressing tube <NUM> such that the first arm <NUM> faces the second arm <NUM>, when the clip main body <NUM> is pulled to the proximal end side of the pressing tube <NUM>. As shown in <FIG>, a width W2 of the second arm <NUM> has substantially the same dimension as a plate width W1 of grasping portion of the clip main body <NUM>. The inner surfaces of the second arm <NUM> and the first arm <NUM> are disposed at mutually facing positions.

The clip main body <NUM> and the operation wire <NUM> are detachably connected to each other via the coupling member <NUM>. The coupling member <NUM> is formed of a metal or resin material. The coupling member <NUM> is disposed at the distal end of the operation wire <NUM> inserted into the sheath <NUM>, and connects the operation wire <NUM> and the clip main body <NUM> to each other. The coupling member <NUM> has a coupler <NUM>, an engaging portion <NUM>, and a small diameter portion <NUM>, sequentially from the proximal end side. The coupling member <NUM> is connected to the operation wire <NUM> by the coupler <NUM>, and is connected to the clip main body <NUM> by the engaging portion <NUM>. The coupling member <NUM> has a pair of grasping clips 91a on the proximal end side of the coupler <NUM>. As shown in <FIG>, the engaging portion <NUM> has a substantially L-shaped base 92b disposed on the distal end side of the small diameter portion <NUM>, and a engaging projection portion 92a disposed so as to protrude from the base 92b in a direction orthogonal to the longitudinal axis L. The engaging projection portion 92a has a shape extending along a shape on the inner surface side of the bending portion <NUM> of the clip main body <NUM>.

The sheath <NUM> is a coil sheath whose wire is densely wound in the direction of the longitudinal axis L. The sheath <NUM> is configured to be flexible and have a sturdy structure resistant to a compressive force in the direction of the longitudinal axis L. As shown in <FIG>, an operation unit <NUM> is connected to the proximal end portion of the sheath <NUM>. The operation wire <NUM> is inserted into the sheath <NUM>, and the proximal end portion of the operation wire <NUM> is connected to a slider <NUM> of the operation unit <NUM>. An operator operates the slider <NUM> of the operation unit <NUM> to slide such that the operation wire <NUM> advances or retracts with respect to the sheath <NUM>.

Next, a connection structure among the clip main body <NUM>, the pressing tube <NUM>, the coupling member <NUM>, and the operation wire <NUM> will be described. The operation wire <NUM> inserted into the sheath <NUM> has an arrowhead hook 60a in the distal end of the operation wire <NUM>. The arrowhead hook 60a and a grasping clip 91a engage with each other, thereby connecting the coupling member <NUM> to the operation wire <NUM>.

The clip main body <NUM> is engaged by the engaging portion <NUM> of the coupling member <NUM> inside the insertion lumen of the pressing tube <NUM>. Specifically, the engaging portion <NUM> and the clip main body <NUM> engage with each other by inserting the bending portion <NUM> through the insertion lumens <NUM>, <NUM>, and <NUM> that are disposed between the engaging projection portion 92a and the base 92b. According to the above-described configuration, the clip main body <NUM> is engaged by the coupling member <NUM> in a state where the clip main body <NUM> is inserted into the pressing tube <NUM>, and the clip main body <NUM> is disposed to be advanceable and retractable with respect to the first insertion lumen <NUM> and the second insertion lumen <NUM> of the pressing tube <NUM> together with the advancement and retraction of the operation wire <NUM> with respect to the sheath <NUM>.

The treatment instrument <NUM> is assembled in the following procedure.

The clip unit <NUM> is installed inside a cartridge (not shown). Once the cartridge is inserted and pressed into the lumen of the sheath <NUM>, the grasping clip 91a and the arrowhead hook 60a engage with each other in the proximal end portion of the cartridge. In this state, if the cartridge is detached therefrom, the clip unit <NUM> is brought into a state where the clip unit <NUM> is accommodated in the distal end portion of the sheath <NUM>, as shown in <FIG>. At this time, the first arm <NUM> accommodated inside the sheath <NUM> is elastically deformed in a direction close to the longitudinal axis L. As shown in <FIG>, a position of the fourth portion <NUM> (distal end of the first arm) in the direction of the longitudinal axis L of the pressing tube <NUM> is located on the distal end side from a position of the distal end portion <NUM> of the second arm <NUM>. The protruding portion 32c is pressed against the inner wall of the lumen of the sheath <NUM>, and is elastically deformed to the inner side (second insertion lumen <NUM> side) of the second tubular portion <NUM>.

In this state, the treatment instrument <NUM> is in an initial state where the treatment instrument <NUM> can be used for surgical treatment. The sheath <NUM> into which the treatment instrument <NUM> is inserted is inserted into an endoscope insertion portion of an endoscope device that is not shown, and the treatment instrument <NUM> is used for ligation treatment.

In the initial state, when the operation wire <NUM> is pulled to the proximal end side, the bending portion <NUM> of the clip main body <NUM> moves to a position more proximal than the third insertion lumen <NUM>. As shown in <FIG>, when the first extension portion <NUM> and the second extension portion <NUM> are disposed in the third insertion lumen <NUM>, the outer surface of the first arm <NUM> is pressed such that the fourth portion <NUM> of the first arm <NUM> is pulled to the proximal end side while being elastically deformed so as to approach the distal end portion <NUM> of the second arm <NUM>.

Next, with regard to an operation of the treatment instrument <NUM> when the ligation treatment is performed, an example of ligating a mucous membrane T inside a gastrointestinal tract will be described with reference to <FIG>.

First, the endoscope insertion portion is inserted into the vicinity of a treatment target area inside the gastrointestinal tract. Subsequently, an operator presses the treatment instrument <NUM> in a state shown in <FIG> so as to protrude the treatment instrument <NUM> from the distal end of the endoscope insertion portion. Furthermore, as shown in <FIG>, when the clip unit <NUM> is pressed so as to protrude from the distal end of the sheath <NUM>, the protruding portion 32c engages with the distal end of the sheath <NUM> such that a movement of the pressing tube <NUM> with respect to the sheath <NUM> in the proximal end direction of the longitudinal axis L is restricted.

Next, when the slider <NUM> of the operation unit <NUM> is operated to slide to the distal end side, the operation wire <NUM> moves relative to the distal end side with respect to the sheath <NUM>, and the coupling member <NUM> is pressed to the distal end side. When the coupling member <NUM> is pressed to the distal end side, the clip main body <NUM> moves to the distal end side inside the pressing tube <NUM>. The second portion <NUM> of the first arm <NUM> protrudes from the distal end of the first tubular portion <NUM>, the pressing force applied to the first arm <NUM> by the first tubular portion <NUM> is released such that the bent shape of the first arm <NUM> is restored, and the distal end portion of the first arm <NUM> moves in a direction spaced from the longitudinal axis L. At this time, the distal end of the first arm <NUM> is spaced from the distal end portion <NUM> of the second arm <NUM> in the direction inclining with respect to the longitudinal axis L.

After a state where the first arm <NUM> and the second arm <NUM> are spaced from each other, the operator advances the sheath <NUM> with respect to the endoscope to cause the distal end portion <NUM> of the second arm <NUM> to press against the mucous membrane T in the vicinity of the ligation area. At this time, the endoscope insertion portion is present inside the gastrointestinal tract, and the ligation area is the mucous membrane T of the gastrointestinal tract. Accordingly, the treatment instrument <NUM> approaches the mucous membrane T in the direction inclining with respect to the mucous membrane T. The first arm <NUM> is located at a spaced position more distal than the distal end portion <NUM> of the second arm <NUM> such that when the distal end portion <NUM> of the second arm <NUM> is pressed against the mucous membrane T in the inclining direction, the distal end portion of the first arm <NUM> also comes into contact with the mucous membrane T, as shown in <FIG>.

Subsequently, as shown in <FIG>, the operator presses the treatment instrument <NUM> into the distal end side and pulls the slider <NUM> of the operation unit <NUM> to the proximal end side to pull the clip main body <NUM> to the proximal end side, in a state where the first arm <NUM> and the distal end portion <NUM> of the second arm <NUM> are pressed against the mucous membrane T. The slider <NUM> is pulled, and the bending portion <NUM> of the clip main body <NUM> is moved by the operation wire <NUM> to a position more proximal than the third insertion lumen <NUM>. Furthermore, when the first extension portion <NUM> and the second extension portion <NUM> are disposed inside the third insertion lumen <NUM>, the fourth portion <NUM> (distal end portion of the first arm) moves in a trajectory in the direction inclining with respect to the proximal end side so as to approach the distal end portion <NUM> of the second arm <NUM>, and the fourth portion <NUM> approaches the distal end portion <NUM> of the second arm <NUM> to enter a closed state. The mucous membrane T to be ligated is grasped between the distal end portion of the first arm <NUM> and the distal end portion <NUM> of the second arm <NUM>, and the first arm <NUM> and the second arm <NUM> function as a grasping portion <NUM> of the mucous membrane T.

The plate width of the third portion <NUM> is wider than the plate width of the second portion <NUM>, and is larger than the opening width of the first tubular portion <NUM>. Accordingly, when the second portion <NUM> is accommodated at a predetermined position inside the first insertion lumen <NUM>, the proximal end portion 27a of the third portion <NUM> comes into contact with the distal end portion of the first tubular portion <NUM>, thereby restricting the clip main body <NUM> from furtherly moving to the proximal end side. The operator recognizes that the clip main body <NUM> is accommodated at the predetermined position inside the pressing tube <NUM>.

When the clip main body <NUM> is pulled to the proximal end side inside the third insertion lumen <NUM> through the first insertion lumen <NUM> and the second insertion lumen <NUM>, the clip main body <NUM> is pulled to the proximal end side while being elastically deformed such that that the fourth portion <NUM> of the first arm <NUM> approaches the distal end portion <NUM> of the second arm <NUM> since the outer surface of the first arm <NUM> is pressed. When the bending portion <NUM>, the first extension portion <NUM>, and the second extension portion <NUM> come into contact with the third insertion lumen <NUM>, the clip is brought into pressurizing contact with the pressing tube <NUM>, and a state where the clip main body <NUM> is connected to the operation wire <NUM> via the coupling member <NUM> is maintained. Accordingly, a position of the pressing tube <NUM> is held in a state where the proximal end portion of the pressing tube <NUM> is inserted into the lumen of the sheath <NUM> and the protruding portion is in contact with the distal end surface of the sheath <NUM>.

In a case where the mucous membrane T cannot be sufficiently grasped, the operation wire <NUM> is pressed outward to the distal side to restore the bent shape of the first arm <NUM>, and the distal end portion of the first arm <NUM> moves in the direction spaced from the longitudinal axis L. In this manner, in a state where the first arm <NUM> and the second arm <NUM> are spaced from each other again, the mucous membrane T can be grasped again.

When the bending portion (connection portion) <NUM> is pulled to a position protruding from the proximal end of the pressing tube <NUM> such that the first arm <NUM> approaches the second arm to close the arm, the projection <NUM> is pressed into the third insertion lumen <NUM>. The projection <NUM> has the above-described serrated shape, and thus, is brought into pressurizing contact with the inner wall of the third insertion lumen <NUM>. The clip main body <NUM> is movable in the direction in which the clip main body <NUM> is pressed into the proximal end side (arm closing direction of the first arm <NUM>), however, a movement of the clip main body <NUM> in a direction in which the clip main body <NUM> is pressed to the distal end side (direction in which the clip main body <NUM> protrudes from the pressing tube <NUM> so as to open the arm of the first arm <NUM>) is restricted, as the projection <NUM> bites in the inner wall of the third insertion lumen <NUM>.

When the operation wire <NUM> is further pulled in a state where the first arm <NUM> and the second arm <NUM> grasp the mucous membrane T, the clip main body <NUM> does not move since the movement to the proximal end side is restricted by the engagement between the third portion <NUM> and the first tubular portion <NUM>. Therefore, a heavy load is applied to the small diameter portion <NUM>, thereby breaking the small diameter portion <NUM>. In this manner, a connection between the operation wire <NUM> and the clip main body <NUM> is released. When the connection between the operation wire <NUM> and the clip main body <NUM> is released, a connection between the second tubular portion <NUM> and the distal end of the sheath <NUM> is also released, and as shown in <FIG>, the pressing tube <NUM> is detached from the sheath <NUM>, thereby placing the clip unit <NUM> after ligating the mucous membrane T. Thereafter, the sheath <NUM>, the operation wire <NUM>, and the proximal end side of the coupling member <NUM> are retracted from the endoscope insertion portion, thereby removing the treatment instrument <NUM> therefrom.

According to the treatment instrument <NUM> of the present embodiment, the grasping portion is configured to include the second arm <NUM> fixed to the pressing tube <NUM> and the first arm <NUM> of the clip main body <NUM> disposed to be advanceable and retractable with respect to the pressing tube <NUM>. Therefore, the second arm <NUM> does not move even when the first arm <NUM> is pulled to the proximal end side of the pressing tube <NUM> in order to grasp a tissue. As a result, the second arm <NUM> can be stably pressed against the tissue without receiving the influence of the pulling operation performed by the operation wire <NUM> on the clip main body <NUM>.

According to the treatment instrument <NUM> of the present embodiment, in the initial state, the position of the fourth portion in the direction of the longitudinal axis L of the pressing tube <NUM> is located on the distal end side from the position of the distal end portion <NUM> of the second arm <NUM>. Accordingly, in a case where the treatment instrument <NUM> performs ligation by moving the clip unit <NUM> close to the ligation area in the oblique direction, both the distal end portions of the first arm <NUM> and the second arm <NUM> can be brought into a state where both of these are in contact with the tissue. In a case where the treatment instrument <NUM> transendoscopically ligates the mucous membrane T of the gastrointestinal tract, it is possible to smoothly perform the ligation process by pinching the mucous membrane T between the first arm <NUM> and the second arm <NUM>.

A relative position of the second arm <NUM> with respect to the tissue can be fixed, and the second arm may not follow an operation in which the clip main body <NUM> is pulled in order to close the first arm <NUM>. Accordingly, compared to the clip unit <NUM> in the related art, it is easy to perform the operation for pulling the clip unit <NUM> to the proximal end side while the clip unit <NUM> is pressed against the tissue.

The aspect according to the present embodiment is not limited to the above-described configurations. As a configuration of each unit, it is conceivable to adopt the following modification examples. Even if the modification examples are appropriately combined with each other, the tissue can be smoothly ligated similarly to the above-described embodiment. In the following description, the same reference numerals will be given to configurations common to the above-described configurations, and description thereof will be omitted.

In a case where the protruding portion 32C is not provided in the pressing tube <NUM>, as shown in <FIG>, a configuration may be adopted in which the movement of the pressing tube <NUM> is restricted by the proximal end of the pressing tube <NUM> coming into contact with the distal end of the sheath <NUM>. In this case, the clip unit <NUM> in an accommodated state in an outer sheath <NUM> is inserted into the endoscope, and is caused to protrude from the distal end of the endoscope insertion portion. Thereafter, as shown in <FIG>, the clip unit <NUM> is caused to protrude from the outer sheath <NUM> and used.

In the present embodiment, a configuration has been described in which the first extension portion <NUM> and the second extension portion <NUM> extend from both ends of the bending portion <NUM> so as to be substantially parallel to each other. However, as shown in <FIG>, a first extension portion 23A and a second extension portion 24A which extend from both end portions of the bending portion <NUM> may be formed in an α-shape in which both of these intersect each other. Alternatively, the first extension portion and the second extension portion may be formed in a tapered shape in which the spaced distance therebetween gradually becomes farther from both ends of the bending portion.

In the clip main body <NUM> according to the present embodiment, an example has been described in which the projection <NUM> is disposed so that the projection <NUM> functions as a wedge inside the third insertion lumen <NUM> and the clip main body <NUM> is fixed to the pressing tube <NUM>, however, the projection <NUM> is not an essential configuration. For example, a configuration may be adopted in which the clip main body is fixed to the pressing tube by adjusting the dimension of the bending portion and the third insertion lumen so as to bring the bending portion and the third insertion lumen into pressurizing contact with each other.

In the present embodiment, an example has been described in which the second arm <NUM> is integrally molded with the second tubular portion <NUM>, however, the second arm may be fixed in a state where the second arm protrudes from the distal end of the pressing tube <NUM>. For example, as shown in <FIG>, a configuration may be adopted in which a second arm 40A is fixed to an outer peripheral surface of a first tubular portion 31A (pressing tube) by means of welding or by using an adhesive.

In the present embodiment, an example has been described in which the distal end portion <NUM> of the second arm <NUM> linearly extends from the first tubular portion <NUM>, however, a configuration may be adopted in which the second arm faces the first arm so as to be capable of grasping the tissue. For example, as shown in <FIG>, a claw portion may be employed in which the distal end portion <NUM> of a second arm 40B is folded in a direction close to the longitudinal axis L of the first tubular portion <NUM>. In this case, as shown in <FIG>, in a closed state of the clip main body <NUM>, the fourth portion <NUM> (distal end of the first arm) of the first arm <NUM> and a claw portion <NUM> (distal end portion of the second arm) face each other, thereby enabling the tissue to be more firmly grasped. Furthermore, if the fourth portion <NUM> (distal end of the first arm) of the first arm <NUM> and the claw portion <NUM> (distal end portion of the second arm) are configured to face each other on the longitudinal axis L, the tissue can be much more firmly grasped.

A second arm 40C may be formed of a material or in a shape which has a rigidness such that an extent that the proximal end portion <NUM> can be bent by an external force. That is, in a state where the external force is not applied to the second arm 40C, as in the second modification example shown in <FIG>, the proximal end portion of the second arm 40B linearly extends on an extension line of the first tubular portion <NUM>. On the other hand, if the external force is applied thereto when the tissue is pressed, as shown in <FIG> and <FIG>, the second arm 40C is rigid to such an extent that the proximal end portion is bent in the direction spaced from the longitudinal axis L of the first tubular portion <NUM>. In this way, the proximal end portion of the second arm 40C is bent, and thus, it is possible to stably hold a position where the distal end of the second arm 40C comes into contact with the tissue. As a result, even if an angle at which the pressing force is applied to the tissue by the treatment instrument <NUM> is changed during the operation, it is possible to stably hold a state where the second arm 40C presses the tissue in the pressing direction. When the second arm 40C presses the tissue, it is possible to prevent the second arm 40C from sliding on and slipping off from the tissue.

An example has been described in which the first tubular portion <NUM> and the second tubular portion <NUM> are joined to each other in the pressing tube <NUM>, however, without being limited thereto, a configuration may be adopted in which the first tubular portion <NUM> and the second tubular portion <NUM> are integrally molded.

For example, an opening shape of the insertion lumens (the first insertion lumen, the second insertion lumen, and the third insertion lumen) of the pressing tube may be a circular shape, an elliptical shape, an oval shape, or a rectangular shape, as long as the shape enables the clip main body and the coupling member to move forward or rearward.

The coupling member <NUM> may be configured so that the coupling member <NUM> is coupled to the distal end of the operation wire <NUM>, and so that the clip main body <NUM> and the operation wire <NUM> are coupled so as to be detachable from each other. For example, the coupling member 90A according to the first modification example shown in <FIG> has a coupler 91A formed from a flat plate which is long in the axial direction of the operation wire <NUM>. The coupler 91A has a through-hole formed to penetrate the proximal end portion of the coupling member 90A in the thickness direction, and has an opening area into which the operation wire <NUM> can be inserted. The distal end of the operation wire <NUM> is inserted into the opening of the coupler 91A of the coupling member 90A. Thereafter, the distal end returns to the proximal end side so as to form a loop, and is fixed to the operation wire <NUM>, thereby coupling the coupling member 90A and the operation wire <NUM> to each other. The distal end side of the coupling member 90A has a hook-shaped engaging portion 92A. The bending portion <NUM> of the clip main body <NUM> is disposed in the hook-shaped portion of the engaging portion 92A, thereby adopting a configuration in which the clip main body <NUM> can be engaged.

The coupling member 90A is configured to be advanceable and retractable in the second insertion lumen <NUM>, in the third insertion lumen <NUM> of the pressing tube <NUM> fixed to the distal end of the sheath <NUM>, and in the lumen of the distal end portion of the sheath <NUM> due to a relative movement of the operation wire <NUM> with respect to the sheath <NUM> by the operation of the operation unit <NUM>.

Alternatively, for example, as another connection structure between the coupling member and the operation wire <NUM>, a structure may be employed in which the coupling member is fixed to the distal end of the operation wire <NUM> by means of welding.

A second modification example of the coupling member is shown in <FIG>. In a coupling member 90B according to the second modification example, an engaging portion 92B is formed in a hook shape which is cut out inward in a rectangular shape from a portion of the outer peripheral edge extending in the direction of the longitudinal axis L. The distal end of the operation wire <NUM> is fixed to a proximal end member <NUM> of the coupling member 90B. A loop wire <NUM> disposed on the distal end side of the proximal end member <NUM> is inserted into a coupler 91B formed from a through-hole.

According to the coupling member 90B of the present modification example, as shown in <FIG>, in a state where the clip main body <NUM> is pulled such that the bending portion <NUM> is disposed more proximal than the second tubular portion <NUM> and the clip main body <NUM> is fixed to the pressing tube <NUM> by the third insertion lumen <NUM> and the projection <NUM>, the coupling member 90B cannot pivotally move inside the sheath <NUM> in the outer circumferential direction of the sheath. Accordingly, the engagement between the engaging portion 92B and the clip main body <NUM> cannot be released in this state. On the other hand, as shown in <FIG>, when the operator moves the operation wire <NUM> toward the distal end side of the sheath <NUM>, the coupling member 90B can pivotally move in the outer circumferential direction of the sheath <NUM> such that the engagement between the engaging portion 92B and the clip main body <NUM> can be released.

<FIG> shows a third modification example of the coupling member. A coupling member 90C according to the third modification example has a small diameter portion 96C between a connection portion side of the operation wire <NUM> and the coupling member 90C and an engaging portion 92C side. The small diameter portion 96C is set to have weaker tensile strength than that of other portions of the coupling member 90C, and is configured so that strong tension is applied to the coupling member 90C and the small diameter portion 96C is broken. According to the coupling member 90C of the present modification example, in a state where the clip main body <NUM> is pulled such that the bending portion <NUM> is disposed more proximal than the second tubular portion <NUM> and the clip main body <NUM> is fixed to the pressing tube <NUM> by the third insertion lumen <NUM> and the projection <NUM>, when the operator further pulls the operation wire <NUM>, the small diameter portion 96C is broken and the connection of the clip main body <NUM> and the operation wire <NUM> is released as the clip main body <NUM> does not move.

In the present modification example, an example has been described in which the small diameter portion 96C is broken so as to release the connection between the clip unit <NUM> and the operation wire <NUM>, however, a configuration may be adopted in which a hooked shape of the engaging portion 92C is broken or plastically deformed so as to release the connection between the clip main body <NUM> and the operation wire <NUM>.

Alternatively, an example has been described in which the treatment instrument <NUM> grasps the tissue by using the first arm <NUM> and the second arm <NUM>, however, a configuration may be adopted in which the treatment instrument <NUM> has an arm fixed to the pressing tube and an arm disposed so as to be advanceable or retractable with respect to the pressing tube so as to grasp the tissue by using these arms. For example, a configuration may be adopted in which two second arms are disposed for the pressing tube so that the first arm grasps the tissue by facing each of the two second arms, or a configuration may be adopted in which a plurality of first arms and second arms are caused to face each other so as to grasp the tissue.

Hitherto, the embodiments according to the present invention have been described with reference to the drawings. However, a specific configuration is not limited to the embodiments, and includes design modifications within the scope not departing from the gist of the present invention.

In addition, a configuration can be adopted by appropriately combining the configuration elements described in the respective embodiments and the respective modification examples with each other. The present invention is not limited by the above description, and is limited by only appended claims.

Claim 1:
An endoscopic treatment instrument (<NUM>), comprising:
a pressing tube (<NUM>) that has an insertion lumen;
a clip main body (<NUM>) that has a first arm (<NUM>), the first arm (<NUM>) being inserted into the insertion lumen such that the first arm (<NUM>) protrudes from a distal end of the pressing tube (<NUM>);
a second arm (<NUM>) that is fixed to the pressing tube (<NUM>) to protrude to a distal end side of the pressing tube (<NUM>); and
an operation wire (<NUM>) that is connected to the clip main body (<NUM>) and configured to retract the clip main body (<NUM>) with respect to the pressing tube (<NUM>),
wherein the first arm (<NUM>) approaches the second arm (<NUM>) while being moved to a proximal end side of the pressing tube (<NUM>) by being pulled by the operation wire (<NUM>),
wherein in an initial state before the clip main body (<NUM>) is pulled by the operation wire (<NUM>), a position of a distal end of the first arm (<NUM>) in a longitudinal axis direction of the pressing tube (<NUM>) is more distal than a position of a distal end of the second arm (<NUM>), and
wherein the distal end of the first arm (<NUM>) is configured to approach the distal end portion of the second arm (<NUM>) when the clip main body (<NUM>) is pulled to the proximal end side of the pressing tube (<NUM>);
characterized in that
the second arm (<NUM>) extends more distally than the distal end side of the pressing tube (<NUM>).