High-frequency treatment instrument

Abstract

A high-frequency treatment tool (1) has: a barrel; a metal wire rod (20), which has a distal end and a proximal end, and in which a portion thereof is exposed outside the barrel and on the distal side of the barrel, the remaining portion thereof being positioned in a first lumen; and a fixture (25) that is fixed to the distal-end part of the wire rod (20), comes in contact with the inner wall of the first lumen, and has a distal end (25A) and a proximal end (25B). The fixture 25 has a first section (30) at least including a portion that decreases in outside diameter toward the distal end (25A) and not including a portion that increases in outside diameter toward the distal end (25A). When the first section (30) is divided into three equal portions, including a distal-end part (31), a central part (32), and a proximal-end part (33), the radial cross-sectional shape of the fixture (25) differs between the proximal end (31B) of the distal-end part (31) and the proximal end (33B) of the proximal-end part (33) of the first section (30).

Description

Technical Field

[0001] The present invention relates to a high-frequency treatment instrument introduced into a living body via an endoscope.

Background Art

[0002] In endoscopic surgeries such as endoscopic sphincterotomy (EST), a treatment instrument for performing a treatment within a body cavity is used via a treatment instrument insertion channel of an endoscope extending from the proximal end side to the distal end side. As such a treatment instrument, a papillotome can be mentioned.

[0003] For example, in treatment instruments disclosed in Patent Documents 1 and 2, a conductive wire (wire) is inserted into a cylinder called a sheath or tube extending from the distal end to the proximal end side, and a part of the wire is exposed outside on the distal end side of the treatment instrument. By passing a high-frequency current through the wire, the tissue such as a lesion can be incised at the exposed part of the wire. A fixing member or a fixture called a knife tip is fixed to the tip of the wire, and the tip of the wire is fixed to the cylinder by arranging the fixture in the inner cavity of the cylinder.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the cylindrical body may be made of a material having high slipperiness such as fluororesin, the fixture may not be closely attached and fixed to the cylindrical body. For this reason, when the wire is advanced and retracted with the operation handle on the operator side, the fixture may slide relative to the cylindrical body, and the wire may rotate idly or come out of the cylindrical body. In addition, since the fixture is arranged in a very thin inner cavity of the cylindrical body, it is difficult to use a method of adhesion with an adhesive or welding a part of the cylindrical body. Therefore, an object of the present invention is to provide a high-frequency treatment instrument capable of closely attaching and fixing a fixture to a cylindrical body so that the wire does not come out of the cylindrical body and does not rotate idly when the wire is advanced and retracted with the operation handle on the operator side.

Means for Solving the Problems

[0006] One embodiment of the high-frequency treatment instrument of the present invention that has solved the above problems has a distal end and a proximal end, a cylindrical body having at least a first inner cavity and a second inner cavity inside, a tip end and a base end, a part of which is exposed outside the cylindrical body on the distal side of the cylindrical body, and the other part is arranged in the first inner cavity, a metal wire, a fixture fixed to the tip end portion of the wire, in contact with the inner wall of the first inner cavity, and having a tip end and a base end. The fixture has at least a first section in which the outer diameter becomes smaller toward the tip end side and does not include a section in which the outer diameter becomes larger toward the tip end side. When the first section is divided into three equal parts: a tip end side portion, a central portion, and a base end side portion, the radial cross-sectional shape of the fixture has a gist in that it is different between the base end of the tip end side portion of the first section and the base end of the base end side portion of the first section. By setting the radial cross-sectional shape of the first section of the fixture in this way, an appropriate frictional resistance is generated when the fixture contacts the inner wall of the first inner cavity of the cylindrical body. Therefore, the fixture can be firmly fixed to the cylindrical body so that the fixture does not slide in the first inner cavity of the cylindrical body. For this reason, even if the wire is advanced and retracted on the operator side, it is possible to prevent the wire from rotating idly and coming out of the cylindrical body.

[0007] In the above high-frequency treatment instrument, it is preferable that the contour of the radial cross-sectional shape of the fixture at the base end of the base end side portion of the first section includes a straight portion.

[0008] In the above high-frequency treatment instrument, it is preferable that the contour of the radial cross-sectional shape of the fixture at the base end of the base end side portion of the first section includes two straight portions intersecting each other.

[0009] In the above high-frequency treatment instrument, a first flat portion and a second flat portion intersecting each other are formed on the outer surface of the base end side portion of the first section of the fixture, and it is preferable that the normal direction of the first flat portion and the normal direction of the second flat portion are different from the direction from the tip end to the base end of the fixture, respectively.

[0010] In the above high-frequency treatment instrument, it is preferable that the contour of the radial cross-sectional shape of the fixture at the base end of the tip end side portion of the first section is composed only of a curved portion.

[0011] In the above high-frequency treatment instrument, it is preferable that the outer diameter of the radial cross-sectional shape of the fixture at the tip of the base end side portion of the first section is larger than the maximum diameter of the first inner cavity.

[0012] In the above high-frequency treatment instrument, the radial cross-sectional shape of the fixture at the base end of the tip end side portion of the first section is circular or oval, and it is preferable that the radial cross-sectional shape of the fixture at the base end of the base end side portion of the first section is polygonal.

[0013] In the above high-frequency treatment instrument, it is preferable that the first section is composed of a portion with a constant outer diameter located on the base end side and a portion with an outer diameter decreasing toward the tip end located on the tip end side.

[0014] In the above high-frequency treatment instrument, the fixture further has a second section located on the base end side of the fixture rather than the first section, including at least a portion where the outer diameter decreases toward the tip end and not including a portion where the outer diameter increases toward the tip end, and it is preferable that the outer diameter of the tip end of the second section of the fixture is smaller than the outer diameter of the base end of the first section.

[0015] In the above high-frequency treatment instrument, when the second section is trisected into a distal end side portion, a central portion, and a proximal end side portion, it is preferable that the outer diameter of the cross-sectional shape in the radial direction of the fixture at the tip of the proximal end side portion of the second section is larger than the maximum diameter of the first inner cavity.

[0016] In the above high-frequency treatment instrument, when the second section is trisected into a distal end side portion, a central portion, and a proximal end side portion, it is preferable that the cross-sectional shape in the radial direction of the fixture is different between the proximal end of the distal end side portion of the second section and the proximal end of the proximal end side portion of the second section.

[0017] In the above high-frequency treatment instrument, it is preferable that the radius of the circumscribed circle of the cross-sectional shape in the radial direction of the fixture at the proximal end of the proximal end side portion of the second section is greater than or equal to the radius of the circumscribed circle of the cross-sectional shape in the radial direction of the fixture at the proximal end of the proximal end side portion of the first section.

[0018] In the above high-frequency treatment instrument, it is preferable that the cross-sectional shape in the radial direction of the fixture at the proximal end of the proximal end side portion of the second section is the same as the cross-sectional shape in the radial direction of the fixture at the proximal end of the proximal end side portion of the first section.

[0019] In the above high-frequency treatment instrument, in the direction from the tip to the proximal end of the fixture, it is preferable that the length of the first section is different from that of the second section.

[0020] In the above high-frequency treatment instrument, in the second section, it is preferable that the fixture is formed in a frustum shape.

[0021] In the above high-frequency treatment instrument, it is preferable that the surface roughness of the proximal end side portion of the second section is greater than the surface roughness of the distal end side portion of the second section. The surface roughness is the arithmetic mean roughness Ra between the reference lengths of the roughness curve in the circumferential direction of the surface of the fixture, and the reference length is one-fourth of the circumferential length of the fixture at each measurement position.

Advantages of the Invention

[0022] According to the above high-frequency treatment instrument, since an appropriate frictional resistance is generated when the fixture abuts against the inner wall of the first inner cavity of the cylindrical body, the fixture can be firmly fixed to the cylindrical body so that the fixture does not slip in the first inner cavity of the cylindrical body. Therefore, even if the wire is advanced and retracted on the hand side, it is possible to prevent the wire from idling or coming out of the cylindrical body.

Brief Description of the Drawings

[0023]

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Embodiments for Carrying Out the Invention

[0024] Hereinafter, the present invention will be described more specifically based on the following embodiments. However, the present invention is not limited by the following embodiments, and it is of course possible to appropriately modify and implement it within the scope that can conform to the gist of the foregoing and following descriptions, and all of them are included in the technical scope of the present invention. In each drawing, for convenience, hatching, reference numerals of members, etc. may be omitted, but in such cases, reference shall be made to the specification and other drawings. Also, the dimensions of various members in the drawings may differ from the actual dimensions because priority is given to facilitating the understanding of the features of the present invention.

[0025] With reference to FIGS. 1 to 12, the configuration of the high-frequency treatment instrument will be described. FIG. 1 shows a side view of the high-frequency treatment instrument according to an embodiment of the present invention, and FIGS. 2 and 3 show an enlarged perspective view and a cross-sectional view (partial side view) of the distal end portion of the high-frequency treatment instrument shown in FIG. 1, respectively. FIGS. 4 and 5 show cross-sectional views taken along line IV-IV and line V-V of the high-frequency treatment instrument shown in FIG. 3, respectively. FIG. 6 shows a perspective view of the fixture shown in FIG. 1 as viewed from the tip side, and FIG. 7 shows a perspective view of the fixture shown in FIG. 1 as viewed from the proximal side. FIG. 8 shows a side view showing the connection state of the fixture and the wire shown in FIG. 3. FIGS. 9 to 11 show cross-sectional views at the proximal end, the distal end of the proximal side portion, and the proximal end of the distal side portion of the first section of the fixture shown in FIG. 8, respectively. FIG. 12 shows a cross-sectional view (partial side view) showing the insertion state of the fixture into the cylindrical body. In FIG. 4, the wire 20 is omitted. The high-frequency treatment instrument 1 has a cylindrical body 10, a wire 20, and a fixture 25.

[0026] The high-frequency treatment instrument 1 is introduced into the body cavity via the treatment instrument insertion channel of the endoscope and is used in surgical procedures such as EST. Hereinafter, the high-frequency treatment instrument may be simply referred to as a treatment instrument. The treatment instrument 1 has an insertion portion 5 that is inserted into the treatment instrument insertion channel of the endoscope and an operation handle 65 connected to the proximal side of the insertion portion 5. A curved portion 8 that is bent according to the shape of the body cavity is preferably formed at the distal end portion of the insertion portion 5, whereby the workability in the body cavity can be improved.

[0027] In the present invention, the distal side of the cylindrical body 10 refers to the tip side in the longitudinal direction of the cylindrical body 10 (in other words, the longitudinal axis direction of the cylindrical body 10) and points to the treatment target side. The proximal side of the cylindrical body 10 refers to the proximal side in the longitudinal direction of the cylindrical body 10 and points to the side near the user (surgeon)'s hand. The tip of the wire 20 refers to the side that is away from the user's hand among one end in the longitudinal axis direction of the wire 20. The proximal end of the wire 20 is the other end in the longitudinal axis direction of the wire 20, that is, the end opposite to the tip, and points to the side close to the user's hand. Unless otherwise specified in the present invention, the inside and outside of the cylindrical body 10, the wire 20, or the fixture 25 refer to the inside and outside in the radial direction of the cylindrical body 10, and the inside in the radial direction of the cylindrical body 10, the wire 20, or the fixture 25 refers to the side closer to the longitudinal axis center of the cylindrical body 10.

[0028] The cylinder 10 has a distal end and a proximal end, and has at least a first inner cavity 11 and a second inner cavity 12 inside. A wire 20 is disposed in the first inner cavity 11, and a fixture 25 described later abuts against the inner wall 11A of the first inner cavity 11. The second inner cavity 12 can be a guide wire insertion passage or a flow path for a liquid injected into the body cavity. Examples of the liquid include physiological saline, hyaluronic acid solution, contrast agent, and other liquids containing drugs or cells.

[0029] As shown in FIGS. 4 to 5, the cylinder 10 may further have a third inner cavity 13. In that case, the second inner cavity 12 can be used as a guide wire insertion passage, and the third inner cavity 13 can be used as a liquid flow path. The first inner cavity 11 may extend from the distal end to the proximal end of the cylinder 10, and the distal end of the first inner cavity 11 may be disposed closer to the proximal side than the distal end of the cylinder 10. The second inner cavity 12 and the third inner cavity 13 preferably extend from the distal end to the proximal end of the cylinder 10. This makes it easier to insert the guide wire and inject the liquid.

[0030] The inner diameters of the first inner cavity 11, the second inner cavity 12, and the third inner cavity 13 may be the same as each other, or may be different from each other. For example, the inner diameter may increase in the order of the first inner cavity 11 in which the wire 20 is disposed, the third inner cavity 13 through which the liquid flows, and the second inner cavity 12 through which the guide wire is inserted. Thereby, the outer diameter of the treatment instrument 1 can be made as small as possible to improve the passability in the body.

[0031] In FIGS. 1 to 3, a first opening 14 and a second opening 15 are provided on the outer peripheral surface of the distal portion (preferably the distal end portion, more preferably the curved portion 8 provided adjacent to the distal end) of the cylinder 10. The first opening 14 is located more distally than the second opening 15. The first inner cavity 11 communicates with the outside of the cylinder 10 through the first opening 14 and the second opening 15.

[0032] As shown in FIG. 3, a third opening 16 may be provided at the distal end of the cylindrical body 10, on the distal side of the first opening 14 and the second opening 15 (preferably, the portion including the distal end of the cylindrical body 10). In that case, the first inner cavity 11 may communicate with the outside of the cylindrical body 10 through the third opening 16. The third opening 16 is preferably located on the distal side of the fixture 25. Although not shown, the portion of the first inner cavity 11 on the distal side of the first opening 14 and the second opening 15 (preferably, the portion including the distal end of the first inner cavity 11) may be sealed.

[0033] A tapered portion 19 with a decreasing outer diameter toward the distal end may be provided at the distal end of the cylindrical body 10 (preferably, the portion including the distal end of the cylindrical body 10). Thereby, the passability of the treatment instrument 1 in the body can be enhanced. In FIG. 2, the first opening 14 and the second opening 15 are located proximal to the tapered portion 19, and the third opening 16 is located at the tapered portion 19. The fixture 25 is located proximal to the tapered portion 19.

[0034] The cylindrical body 10 can be provided with additional openings for protruding a guide wire inserted into the inner cavity of the cylindrical body 10 or for discharging liquid into the body cavity. For example, in FIGS. 2 to 3, a fourth opening 17 is provided at the distal end of the cylindrical body 10, and the second inner cavity 12 communicates with the outside of the cylindrical body 10 through the fourth opening 17. Thereby, the guide wire can be protruded from the fourth opening 17. A fifth opening 18 is preferably provided on the outer peripheral surface of the distal end portion of the cylindrical body 10 (preferably, the portion including the distal end of the cylindrical body 10), and the third inner cavity 13 communicates with the outside of the cylindrical body 10 through the fifth opening 18. Thereby, liquid can be discharged into the body cavity through the fifth opening 18. Note that the fifth opening 18 may be located at the tapered portion 19.

[0035] The cylinder body 10 preferably has flexibility. Thereby, the cylinder body 10 can be deformed along the body cavity shape. For shape retention, the cylinder body 10 preferably has elasticity. The material constituting the cylinder body 10 can be a resin or a metal. Examples of the resin constituting the cylinder body 10 include polyamide-based resins, polyester-based resins, polyurethane-based resins, polyolefin-based resins, fluorine-based resins, vinyl chloride-based resins, silicone-based resins, natural rubber, etc. These may be used alone or in combination of two or more. Examples of the metal constituting the cylinder body 10 include stainless steels such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, Ni-Ti alloys, Co-Cr alloys, or combinations thereof. The cylinder body 10 includes those in which a resin is coated on the surface of a long body made of metal. Among them, the cylinder body 10 is preferably a resin tube, and more preferably a fluorine-based resin tube. The cylinder body 10 can have a laminated structure of different materials or the same material, or a structure in which a plurality of tubes are joined together.

[0036] In a cross-section perpendicular to the longitudinal axis direction of the cylinder body 10, the outer shape of the cylinder body 10 is not particularly limited, and can be, for example, circular, oval, polygonal, or a combination of these. Oval shapes include elliptical, egg-shaped, and rounded rectangular shapes. The same applies to the following description.

[0037] The portion of the inner wall 11A of the first inner cavity 11 that abuts against the fixture 25 may have irregularities. Thereby, the frictional resistance between the cylinder body 10 and the fixture 25 can be increased. On the other hand, the inner walls of the second inner cavity 12 and the third inner cavity 13 are preferably more slippery than the portion of the inner wall 11A of the first inner cavity 11 where irregularities are provided. Thereby, the slidability of the guide wire inserted into the second inner cavity 12 can be increased, or the pressure loss of the liquid flowing through the third inner cavity 13 can be suppressed.

[0038] The wire 20 includes a portion that functions as the knife part of a so-called high-frequency knife. The wire 20 is made of metal and has electrical conductivity. The wire 20 has a distal end and a proximal end, with a part of it being exposed outside the distal side of the cylindrical body 10 and the other part being disposed in the first inner cavity 11. In FIG. 3, a part of the distal portion of the wire 20 is exposed outside the cylindrical body 10 through the first opening 14 and the second opening 15 of the cylindrical body 10. At a position proximal to the second opening 15 and distal to the first opening 14, the wire 20 is arranged in the first inner cavity 11. Since the wire 20 has electrical conductivity, the wire 20 can be used as the knife part of a high-frequency knife by passing a high-frequency current through the wire 20. Preferably, an insulating layer is provided on the surface of the portion of the wire 20 disposed within the cylindrical body 10, and no insulating layer is provided on the portion exposed from the cylindrical body 10. Thereby, only the portion of the wire 20 without the insulating layer can be used as the knife part. Note that the portion of the wire 20 exposed from the cylindrical body 10 is shorter than the portion disposed in the first inner cavity 11 of the cylindrical body 10.

[0039] As a whole, the wire 20 extends from the distal side to the proximal side of the cylindrical body 10. In FIG. 3, a fixture 25 is fixed to the tip of the wire 20, and the fixture 25 is in contact with the inner wall 11A of the first inner cavity 11 of the cylindrical body 10. Although not shown, the wire 20 may have a portion in contact with the inner wall 11A of the first inner cavity 11 of the cylindrical body 10.

[0040] The proximal end of the wire 20 is connected to an operation handle 65 described later. The proximal end of the wire 20 is connected to a high-frequency power source so as to ensure electrical conductivity. By performing the forward and backward operation of the wire 20 with the operation handle 65, the length and the degree of deflection of the portion of the wire 20 exposed from the cylindrical body 10 can be changed. Therefore, the shape of the knife can be changed according to the procedure. The degree of bending of the distal portion of the cylindrical body 10 and the bending portion 8 can also be changed with the operation handle 65.

[0041] The wire 20 is preferably made of an elastically deformable material. The wire 20 only needs to have elasticity to such an extent that its shape changes along the cylindrical body 10. The wire 20 can be made of, for example, a superelastic alloy such as a Ni-Ti based alloy, or stainless steel such as SUS303, SUS304, SUS316, etc. The wire 20 may be formed from a single member, or may be formed by joining a plurality of members in the middle of the longitudinal axis direction. As a joining method of the wire 20, for example, in addition to a method of caulking the ends of a plurality of wires 20 together with a metal tube, welding and adhesion can be used. The wire 20 may be a single wire, or may be a stranded wire formed by twisting single wires. If it is a single wire, the manufacturing is easy. If it is a stranded wire, the strength of the wire 20 can be increased, so that the operation on the hand side is easily transmitted to the distal end portion of the treatment instrument 1.

[0042] The fixture 25 is provided for fixing the wire 20 to the cylindrical body 10. As shown in FIG. 3, the fixture 25 is fixed to the tip of the wire 20 and is in contact with the inner wall 11A of the first inner cavity 11. As shown in FIGS. 6 to 8, the fixture 25 has a tip 25A and a base end 25B. Frictional resistance is generated when the fixture 25 contacts the inner wall 11A of the first inner cavity 11, and the fixture 25 is fixed to the cylindrical body 10. As shown in FIGS. 3 and 8, the tip 25A of the fixture 25 is located on the tip side of the wire 20, and the direction x from the tip 25A to the base end 25B of the fixture 25 coincides with the direction from the tip to the base end of the wire 20.

[0043] As shown in FIG. 3, the fixture 25 can be disposed in the first inner cavity 11 such that the tip 25A of the fixture 25 faces the distal end side of the cylindrical body 10. Thereby, since the longitudinal axis direction of the wire 20 generally extends from the distal side to the proximal side of the cylindrical body 10, kinking of the wire 20 can be prevented. Such a treatment instrument 1 is obtained by disposing the fixture 25 on the distal side of the first opening 14.

[0044] Although not shown, the fixture 25 may be disposed in the first inner cavity 11 such that the tip 25A of the fixture 25 faces the proximal end side of the cylindrical body 10. In that case, a part of the wire 20 in the longitudinal axis direction is arranged to be folded back. Thereby, the portion of the wire 20 exposed from the cylindrical body 10 can be extended so as to project outward in the radial direction of the cylindrical body 10. Such a treatment tool 1 is obtained by disposing the fixture 25 between the first opening 14 and the second opening 15.

[0045] As shown in FIGS. 6 to 12, the fixture 25 has a first section 30 that includes at least a portion where the outer diameter decreases toward the tip 25A side and does not include a portion where the outer diameter increases toward the tip 25A side. When the first section 30 is equally divided into a tip side portion 31, a central portion 32, and a base end side portion 33, the radial cross-sectional shape of the fixture 25 is different between the base end 31B of the tip side portion 31 of the first section 30 and the base end 33B of the base end side portion 33 of the first section 30. By setting the radial cross-sectional shape of the first section 30 of the fixture 25 in this way, an appropriate frictional resistance is generated when the fixture 25 abuts against the inner wall 11A of the first inner cavity 11 of the cylindrical body 10. Therefore, the fixture 25 can be firmly fixed to the cylindrical body 10 so that the fixture 25 does not slide in the first inner cavity 11 of the cylindrical body 10. For this reason, even if the wire 20 is advanced and retracted on the hand side, it is possible to prevent the wire 20 from idling or coming out of the cylindrical body 10 of the wire 20. Further, by using such a fixture 25, the fixture 25 can be disposed in a very thin inner cavity of the cylindrical body 10. As a result, even if it is difficult to adhere by an adhesive or weld a part of the cylindrical body 10, or the cylindrical body 10 is made of a material such as a fluororesin that is difficult to fix by adhesion, the fixture 25 can be fixed so as not to slide in the first inner cavity 11 of the cylindrical body 10.

[0046] The first section 30 is configured to be composed of (a) only a portion where the outer diameter decreases toward the tip 25A side or (b) a portion where the outer diameter is constant and does not change and a portion where the outer diameter decreases toward the tip 25A side. That is, in the first section 30, there is no portion where the outer diameter of the fixture 25 increases toward the tip 25A side.

[0047] As shown in FIG. 8, the first section 30 preferably includes a portion located on the proximal end 25B side with a constant outer diameter and a portion located on the distal end 25A side with an outer diameter that decreases toward the distal end 25A. Specifically, in FIG. 8, the outer diameter of the fixture 25 does not change constantly at the proximal end side of the proximal end side portion 33, and the outer diameter of the fixture 25 decreases toward the distal end side 25A in the portion distal from the approximate center position of the proximal end side portion 33. Since the first section 30 has a portion with a constant outer diameter on the proximal end 25B side, the fixture 25 is firmly fixed within the first inner cavity 11 of the cylindrical body 10.

[0048] Examples of the shape of the portion where the outer diameter does not change constantly in the first section 30 of the fixture 25 include a prismatic shape, a cylindrical shape, and an oval cylindrical shape. Examples of the shape of the portion where the outer diameter decreases toward the distal end side in the first section 30 of the fixture 25 include frustum shapes such as a frustum of a pyramid shape, a frustum of a cone shape, a frustum of an oval cone shape, and a rounded frustum of a cone shape.

[0049] In the first section 30, the radial cross-sectional shape (outer shape) of the fixture 25 can be circular, oval, polygonal, or a combination of these.

[0050] It is sufficient that the first section 30 is arranged in a part of the fixture 25. Among them, the first section 30 is preferably located at the foremost end of the fixture 25. Thereby, the first section 30 can be arranged at a position away from the insertion port (the first opening 14 in FIG. 3) of the fixture 25 of the cylindrical body 10, and the fixture 25 can be made difficult to come off from the cylindrical body 10.

[0051] Although not shown, the fixture 25 may be composed only of the first section 30. That is, the distal end of the first section 30 may coincide with the distal end 25A of the fixture 25, and the proximal end of the first section 30 may coincide with the proximal end 25B of the fixture 25.

[0052] As shown in FIG. 12, it is preferable that the base end 33B of the proximal end side portion 33 of the first section 30 of the fixture 25 abuts against the inner wall 11A of the first inner cavity 11 of the cylindrical body 10. More preferably, the entire proximal end side portion 33 of the first section 30 of the fixture 25 abuts against the inner wall 11A of the first inner cavity 11 of the cylindrical body 10. Thereby, the fixture 25 can be firmly fixed to the cylindrical body 10.

[0053] As shown in FIG. 12, it is preferable that the outer diameter of the radial cross-sectional shape of the fixture 25 at the base end 33B of the proximal end side portion 33 of the first section 30 is larger than the maximum diameter of the first inner cavity 11. By setting the outer diameter of the fixture 25 in this way, the fixture 25 is more likely to bite into the inner wall 11A of the cylindrical body 10. As a result, the fixture 25 can be firmly fixed to the cylindrical body 10 so that the fixture 25 does not slide in the first inner cavity 11 of the cylindrical body 10.

[0054] As shown in FIG. 9, the contour 34 of the radial cross-sectional shape of the fixture 25 at the base end 33B of the proximal end side portion 33 of the first section 30 preferably includes a straight portion 34A. Thereby, in the radial cross-section of the fixture 25, the fixture 25 is more likely to abut against the cylindrical body 10 such that the straight portion 34A bites into the inner wall 11A of the first inner cavity 11 of the cylindrical body 10.

[0055] As shown in FIG. 9, the contour 34 of the radial cross-sectional shape of the fixture 25 at the base end 33B of the proximal end side portion 33 of the first section 30 preferably includes two straight portions 34A that intersect each other. In that case, it is preferable that a corner portion 35 is formed by the two straight portions 34A that intersect each other. By providing such a corner portion 35, the fixture 25 is more likely to abut against the inner wall 11A of the cylindrical body 10 so as to bite in deeper. In FIG. 9, in the radial cross-section of the fixture 25 at the base end 33B of the proximal end side portion 33 of the first section 30, four corner portions 35 formed by the two straight portions 34A that intersect each other are formed. In the radial cross-section of the fixture 25 at the base end 33B of the proximal end side portion 33 of the first section 30, the corner portions 35 are preferably arranged in the circumferential direction of the fixture 25, and more preferably arranged at equal intervals in the circumferential direction.

[0056] It is preferable that the radial cross-sectional shape of the fixture 25 at the base end 33B of the proximal end side portion 33 of the first section 30 is polygonal. In FIG. 9, the radial cross-sectional shape of the fixture 25 at the base end 33B of the proximal end side portion 33 of the first section 30 is square.

[0057] Although not shown, the contour 34 of the radial cross-sectional shape of the fixture 25 at the base end 33B of the proximal end side portion 33 of the first section 30 may include a curved portion.

[0058] In a predetermined range in the direction x from the tip 25A to the base end 25B of the fixture 25, it is preferable that the fixture 25 abuts against the inner wall 11A of the cylindrical body 10, and it is more preferable that it bites into the inner wall 11A. As such an aspect, for example, as shown in FIGS. 6 to 8, a first flat portion 36A and a second flat portion 36B that intersect each other are formed on the outer surface of the proximal end side portion 33 of the first section 30 of the fixture 25, and the normal direction 37A of the first flat portion 36A and the normal direction 37B of the second flat portion 36B are preferably different from the direction x from the tip 25A to the base end 25B of the fixture 25, respectively. A sharp edge portion 38 extending in the direction x can be formed by the two flat portions. By the edge portion 38 biting into the inner wall 11A of the cylindrical body 10, the fixture 25 can be firmly fixed to the cylindrical body 10.

[0059] In FIGS. 6 to 8, the first flat portion 36A is parallel to the direction from the tip 25A to the base end 25B of the fixture 25. Similarly, the second flat portion 36B is also parallel to the direction from the tip 25A to the base end 25B of the fixture 25. By setting the angle of the flat portion with respect to the direction from the tip 25A to the base end 25B of the fixture 25 in this way, the edge portion 38 can be provided over a wide range of the proximal end side portion 33 of the first section 30.

[0060] Although not shown, the first flat portion 36A may be inclined with respect to the longitudinal axis direction of the wire 20. For example, the first flat portion 36A may be inclined by 5 degrees or more, 10 degrees or more, or 15 degrees or more with respect to the longitudinal axis direction of the wire 20, and may be inclined by 45 degrees or less, 40 degrees or less, or 35 degrees or less. The same applies to the inclination angle of the second flat portion 36B with respect to the longitudinal axis direction of the wire 20. The inclination angles of the first flat portion 36A and the second flat portion 36B with respect to the longitudinal axis direction of the wire 20 may be the same as each other, or may be different from each other.

[0061] The angle formed between the first flat portion 36A and the second flat portion 36B is preferably 150 degrees or less, more preferably 130 degrees or less, and even more preferably 110 degrees or less. Thereby, the edge portion 38 is likely to bite into the inner wall 11A of the cylindrical body 10. The lower limit of the angle formed between the first flat portion 36A and the second flat portion 36B is not particularly limited, but for example, it is also acceptable to be 20 degrees or more, 40 degrees or more, or 60 degrees or more.

[0062] As shown in FIG. 10, the contour 34 of the radial cross-sectional shape of the fixture 25 at the tip 33A of the proximal end side portion 33 of the first section 30 preferably includes a straight portion 34A. Thereby, even at the tip 33A of the proximal end side portion 33 of the first section 30 of the fixture 25, the fixture 25 is likely to abut so as to bite into the inner wall 11A of the cylindrical body 10.

[0063] Although not shown, similar to the case of the proximal end 33B of the proximal end side portion 33 of the first section 30, the contour 34 of the radial cross-sectional shape of the fixture 25 at the tip 33A of the proximal end side portion 33 may include two intersecting straight portions. In that case, it is preferable that a corner portion is formed by the two intersecting straight portions 34A. By providing such a corner portion, the fixture 25 is likely to abut so as to bite deeper into the inner wall 11A of the cylindrical body 10 even at the tip 33A of the proximal end side portion 33.

[0064] As shown in Fig. 10, the contour 34 of the radial cross-sectional shape of the fixture 25 at the tip 33A of the proximal end side portion 33 of the first section 30 may include a straight portion 34A and a curved portion 34B. Thereby, while firmly fixing the fixture 25 to the cylindrical body 10 so that the fixture 25 does not slide in the first inner cavity 11 of the cylindrical body 10, it becomes easier to insert the fixture 25 into the first inner cavity 11. As shown in Fig. 10, the straight portion 34A and the curved portion 34B of the contour 34 of the radial cross-sectional shape of the fixture 25 at the tip 33A of the proximal end side portion 33 of the first section 30 may be alternately arranged. As a result, the radial cross-sectional shape of the fixture 25 at the tip 33A of the proximal end side portion 33 of the first section 30 may be a rounded square.

[0065] In Figs. 9 to 10, the radial cross-sectional shape of the fixture 25 is different between the tip 33A of the proximal end side portion 33 of the first section 30 and the base end 33B of the proximal end side portion 33 of the first section 30, but it may be the same.

[0066] As shown in Fig. 12, it is preferable that the tip 33A of the proximal end side portion 33 of the first section 30 is in contact with the inner wall 11A of the cylindrical body 10. Thereby, it becomes easier to firmly fix the fixture 25 to the cylindrical body 10. It is more preferable that the outer diameter of the contour 34 of the radial cross-sectional shape of the fixture 25 at the tip 33A of the proximal end side portion 33 of the first section 30 is larger than the maximum diameter of the first inner cavity 11. Thereby, it becomes easier for the fixture 25 to bite into the cylindrical body 10 even at the tip 33A of the proximal end side portion 33 of the first section 30.

[0067] As shown in Fig. 11, it is preferable that the contour 34 of the radial cross-sectional shape of the fixture 25 at the base end 31B of the distal end side portion 31 of the first section 30 is composed only of the curved portion 34B. Thereby, the frictional resistance generated between the base end 31B of the distal end side portion 31 of the first section 30 of the fixture 25 and the cylindrical body 10 can be suppressed, and it becomes easier to insert the fixture 25 into the first inner cavity 11. For the same reason, it is preferable that the contour of the radial cross-sectional shape of the fixture 25 at the tip 31A of the distal end side portion 31 of the first section 30 is also composed only of a curved portion.

[0068] Although not shown, the contour 34 of the radial cross-sectional shape of the fixture 25 at the proximal end 31B of the distal end side portion 31 of the first section 30 may include a straight portion. In that case, the total length of the straight portions included in the contour 34 of the radial cross-sectional shape of the fixture 25 at the proximal end 31B of the distal end side portion 31 of the first section 30 is preferably shorter than the total length of the straight portions included in the contour 34 of the radial cross-sectional shape of the fixture 25 at the proximal end 33B of the proximal end side portion 33 of the first section 30. By shortening the straight portion in this way, the frictional resistance generated between the proximal end 31B of the distal end side portion 31 of the first section 30 and the cylindrical body 10 is suppressed, and it becomes easier to insert the fixture 25 into the first lumen 11.

[0069] The radial cross-sectional shape of the fixture 25 at the proximal end 31B of the distal end side portion 31 of the first section 30 is preferably circular or oval. In FIG. 11, the radial cross-sectional shape of the fixture 25 at the proximal end 31B of the distal end side portion 31 of the first section 30 is circular. This makes it easier to insert the fixture 25 into the first lumen 11. For the same reason, the radial cross-sectional shape of the fixture 25 at the distal end 31A of the distal end side portion 31 of the first section 30 is preferably circular or oval.

[0070] In FIGS. 10 and 11, the radial cross-sectional shape of the fixture 25 is different between the proximal end 31B of the distal end side portion 31 of the first section 30 and the distal end 33A of the proximal end side portion 33 of the first section 30, but they may be the same.

[0071] As shown in FIG. 11, the radial cross-sectional shape of the fixture 25 at the proximal end 31B of the distal end side portion 31 of the first section 30 is circular or oval, and as shown in FIG. 9, the radial cross-sectional shape of the fixture 25 at the proximal end 33B of the proximal end side portion 33 of the first section 30 is preferably polygonal. Thereby, on the proximal end side portion 33 side of the first section 30 of the fixture 25, the fixture 25 can be firmly fixed to the cylindrical body 10. Also, on the distal end side portion 31 side of the first section 30 of the fixture 25, it becomes easier to insert the fixture 25 into the first lumen 11.

[0072] As shown in FIG. 12, the tip side portion 31 of the first section 30 of the fixture 25 may be in contact with the inner wall 11A of the cylindrical body 10. Thereby, since the contact area between the fixture 25 and the cylindrical body 10 becomes large, the fixture 25 can be firmly fixed to the cylindrical body 10. Although not shown, the entire tip side portion 31 of the first section 30 of the fixture 25 may be in contact with the inner wall 11A of the cylindrical body 10. The outer diameter of the radial cross-sectional shape of the fixture 25 at the tip 31A of the tip side portion 31 of the first section 30 may be larger than the maximum diameter of the first inner cavity 11.

[0073] In order to ensure the ease of inserting the fixture 25 into the first inner cavity 11, at least a part of the tip side portion 31 of the first section 30 of the fixture 25 may not be in contact with the inner wall 11A of the cylindrical body 10. For example, the tip 31A of the tip side portion 31 of the first section 30 of the fixture 25 may not be in contact with the inner wall 11A of the cylindrical body 10.

[0074] The surface roughness of the base end side portion 33 of the first section 30 is preferably larger than the surface roughness of the tip side portion 31 of the first section 30. Thereby, when the base end side portion 33 of the first section 30 of the fixture 25 comes into contact with the inner wall 11A of the first inner cavity 11 of the cylindrical body 10, an appropriate frictional resistance can be generated. Also, it becomes easier to insert the tip side portion 31 of the first section 30 into the first inner cavity 11. The surface roughness is the arithmetic mean roughness Ra between the reference lengths of the roughness curve in the circumferential direction of the surface of the fixture 25, and the reference length is one-fourth of the circumferential length of the fixture 25 at each measurement position.

[0075] The arithmetic mean roughness Ra corresponds to the arithmetic mean roughness Ra defined in JIS B 0601 (2001) and is measured in accordance with JIS B 0633 (2001). For the measurement, a measuring instrument defined in JIS B 0651 (2001) (for example, an ultra-precision non-contact three-dimensional measuring device manufactured by Mitaka Kohki Co., Ltd., model: NH-3SP) is used.

[0076] The fixture 25 may include a plurality of first sections 30. The plurality of first sections 30 can be arranged to be aligned in the direction x from the tip 25A to the base end 25B of the fixture 25. By providing a plurality of first sections 30, the contact area between the fixture 25 and the cylindrical body 10 can be increased, so that the fixture 25 is more firmly fixed to the cylindrical body 10. It is preferable that the tip of the first section 30 arranged on the most tip side is arranged in a portion including the tip 25A of the fixture 25.

[0077] Furthermore, the fixture 25 has a second section 40 located on the base end 25B side of the fixture 25 rather than the first section 30, and includes at least a portion where the outer diameter becomes smaller toward the tip 25A side and does not include a portion where the outer diameter becomes larger toward the tip 25A side. It is preferable that the outer diameter of the tip of the second section 40 of the fixture 25 is smaller than the outer diameter of the base end of the first section 30. By providing the second section 40 in this way, the contact area between the fixture 25 and the cylindrical body 10 can be increased, so that the fixture 25 is more firmly fixed to the cylindrical body 10.

[0078] The second section 40 is configured to be composed of (a) only a portion where the outer diameter becomes smaller toward the tip 25A side or (b) a portion where the outer diameter is constant and does not change and a portion where the outer diameter becomes smaller toward the tip 25A side. That is, in the second section 40, similar to the first section 30, there is no portion where the outer diameter of the fixture 25 becomes larger toward the tip 25A side.

[0079] Similar to the first section 30, examples of the shape of the portion where the outer diameter of the second section 40 of the fixture 25 is constant and does not change include a prismatic shape, a cylindrical shape, and an oval cylindrical shape. Examples of the shape of the portion where the outer diameter of the second section 40 of the fixture 25 becomes smaller toward the tip side include a frustum shape such as a frustum of a pyramid shape, a frustum of a cone shape, a frustum of an elliptical cone shape, and a rounded frustum of a cone shape. Note that the shape of the second section 40 of the fixture 25 may be the same as or different from the shape of the first section 30.

[0080] In the second section 40, the radial cross-sectional shape (outer shape) of the fixture 25 can be circular, oval, polygonal, or a combination thereof.

[0081] In FIGS. 6 to 8, a first section 30 is provided on the tip 25A side of the fixture 25, and a second section 40 is provided on the base end 25B side of the fixture 25 rather than the first section 30. The second section 40 is divided into three equal parts: a tip side portion 41, a central portion 42, and a base end side portion 43. FIGS. 13 to 15 show radial cross-sectional views at the base end 43B of the base end side portion 43, the tip 43A of the base end side portion 43, and the base end 41B of the tip side portion 41 of the second section 40 of the fixture 25 shown in FIG. 8, respectively. In the embodiments shown in FIGS. 13 and 15, the radial cross-sectional shape of the fixture 25 is different between the base end 41B of the tip side portion 41 of the second section 40 and the base end 43B of the base end side portion 43 of the second section 40, as in the case of the first section 30. In this embodiment, the second section 40 can also be regarded as the first section 30. That is, in the treatment tool 1 shown in FIGS. 6 to 8, it can also be said that two first sections 30 are provided.

[0082] As shown in FIGS. 6 to 8, the second section 40 is preferably adjacent to the first section 30. Thereby, it is possible to limit the portion where the rigidity of the cylindrical body 10 is increased by inserting the fixture 25. Although not shown, the second section 40 may be arranged away from the first section 30.

[0083] In order to fix the fixture 25 more firmly to the cylindrical body 10, for the same reason as the first section 30, the second section 40 preferably also has the following configuration.

[0084] As shown in FIG. 12, it is preferable that the base end 43B of the proximal end side portion 43 of the second section 40 of the fixture 25 abuts against the inner wall 11A of the first inner cavity 11 of the cylindrical body 10. More preferably, the entire proximal end side portion 43 of the second section 40 of the fixture 25 abuts against the inner wall 11A of the first inner cavity 11 of the cylindrical body 10. Further, it is preferable that the outer diameter of the radial cross-sectional shape of the fixture 25 at the base end 43B of the proximal end side portion 43 of the second section 40 is larger than the maximum diameter of the first inner cavity 11.

[0085] As shown in FIG. 13, it is preferable that the contour 44 of the radial cross-sectional shape of the fixture 25 at the base end 43B of the proximal end side portion 43 of the second section 40 includes a straight portion 44A.

[0086] As shown in FIG. 13, it is preferable that the contour 44 of the radial cross-sectional shape of the fixture 25 at the base end 43B of the proximal end side portion 43 of the second section 40 includes two straight portions 44A that intersect each other. In that case, in the radial cross-section of the fixture 25, it is preferable that a corner portion 45 is formed by the two straight portions 44A that intersect each other. In the radial cross-section of the fixture 25 at the base end 43B of the proximal end side portion 43 of the second section 40, the corner portions 45 are preferably arranged in the circumferential direction of the fixture 25, and more preferably arranged at equal intervals in the circumferential direction.

[0087] It is preferable that the radial cross-sectional shape of the fixture 25 at the base end 43B of the proximal end side portion 43 of the second section 40 is polygonal. In FIG. 13, the radial cross-sectional shape of the fixture 25 at the base end 43B of the proximal end side portion 43 of the second section 40 is square.

[0088] Although not shown, it is preferable that the tip of the corner portion 35 of the proximal end side portion 33 of the first section 30 and the tip of the corner portion 45 of the proximal end side portion 43 of the second section 40 are arranged at different positions in the circumferential direction of the fixture 25. By shifting the corner portions 35 and 45 in this way, the fixture 25 is more firmly fixed to the cylindrical body 10.

[0089] Although not shown, the radial cross-sectional shape of the fixture 25 at the base 43B of the proximal side portion 43 of the second section 40 may be rotationally symmetric with the radial cross-sectional shape of the fixture 25 at the base 33B of the proximal side portion 33 of the first section 30.

[0090] Although not shown, the contour 44 of the radial cross-sectional shape of the fixture 25 at the base 43B of the proximal side portion 43 of the second section 40 may include a curved portion.

[0091] In a predetermined range in the direction x from the tip 25A to the base 25B of the fixture 25, it is preferable that the second section 40 of the fixture 25 abuts against the inner wall 11A of the cylindrical body 10, and it is more preferable that it bites into the inner wall 11A. As such an aspect, as shown in FIGS. 6 to 8, a first flat portion 46A and a second flat portion 46B that intersect each other are formed on the outer surface of the proximal side portion 43 of the second section 40 of the fixture 25. In this case, it is preferable that the normal direction 47A of the first flat portion 46A and the normal direction 47B of the second flat portion 46B are each different from the direction x from the tip 25A to the base 25B of the fixture 25. Thereby, an edge portion 48 can be formed in the same manner as the first section 30. Similar to the corner portion, it is preferable that the edge portion 38 of the proximal side portion 33 of the first section 30 and the edge portion 48 of the proximal side portion 43 of the second section 40 are arranged at different positions in the circumferential direction of the fixture 25.

[0092] The angles of the first flat portion 46A and the second flat portion 46B of the second section 40 with respect to the longitudinal axis direction of the wire 20 can be set in the same manner as the first section 30. Also, the angle formed by the first flat portion 46A and the second flat portion 46B can be set in the same manner as the angle formed by the first flat portion 36A and the second flat portion 36B.

[0093] As shown in FIG. 14, it is preferable that the contour 44 of the radial cross-sectional shape of the fixture 25 at the tip 43A of the proximal end side portion 43 of the second section 40 includes a straight portion 44A. Although not shown, the contour 44 of the radial cross-sectional shape of the fixture 25 at the tip 43A of the proximal end side portion 43 of the second section 40 may include two straight portions intersecting each other. Further, the contour 44 of the radial cross-sectional shape of the fixture 25 at the tip 43A of the proximal end side portion 43 of the second section 40 may include a straight portion 44A and a curved portion 44B. In FIGS. 13 to 14, although the radial cross-sectional shape of the fixture 25 is different between the tip 43A of the proximal end side portion 43 of the second section 40 and the base end 43B of the proximal end side portion 43 of the second section 40, they may be the same.

[0094] As shown in FIG. 12, it is preferable that the tip 43A of the proximal end side portion 43 of the second section 40 is in contact with the inner wall 11A of the cylindrical body 10. Further, it is preferable that the outer diameter of the radial cross-sectional shape of the fixture 25 at the tip 43A of the proximal end side portion 43 of the second section 40 is larger than the maximum diameter of the first inner cavity 11. Thereby, it becomes easier for the fixture 25 to bite into the cylindrical body 10 even at the tip 43A of the proximal end side portion 43 of the second section 40.

[0095] The radial cross-sectional shape of the fixture 25 at the base end 41B of the distal end side portion 41 of the second section 40 may be the same as or different from the radial cross-sectional shape of the fixture 25 at the base end 31B of the distal end side portion 31 of the first section 30.

[0096] The contour 44 of the radial cross-sectional shape of the fixture 25 at the base end 41B of the distal end side portion 41 of the second section 40 may include a straight portion, may include a curved portion, or may include both a straight portion and a curved portion.

[0097] As shown in FIGS. 14 to 15, the radial cross-sectional shape of the fixture 25 may be different between the tip 43A of the proximal end side portion 43 of the second section 40 and the base end 43B of the proximal end side portion 43 of the second section 40.

[0098] As shown in FIGS. 13 and 15, the radial cross-sectional shape of the fixture 25 may be different between the proximal end 41B of the distal end side portion 41 of the second section 40 and the proximal end 43B of the proximal end side portion 43 of the second section 40. It is sufficient that at least the proximal end 43B of the proximal end side portion 43 of the second section 40 has a shape that easily contacts the inner wall 11A of the cylindrical body 10.

[0099] As shown in FIGS. 13 and 15, the radial cross-sectional shape of the fixture 25 may be different between the proximal end 41B of the distal end side portion 41 of the second section 40 and the distal end 43A of the proximal end side portion 43 of the second section 40.

[0100] As shown in FIGS. 9 and 13, it is preferable that the radius of the circumscribed circle 49 of the radial cross-sectional shape of the fixture 25 at the proximal end 43B of the proximal end side portion 43 of the second section 40 is greater than or equal to the radius of the circumscribed circle 39 of the radial cross-sectional shape of the fixture 25 at the proximal end 33B of the proximal end side portion 33 of the first section 30. Thereby, since the second section 40 is more likely to contact the inner wall 11A of the cylindrical body 10 than the first section 30, the fixture 25 is more likely to be firmly fixed to the cylindrical body 10.

[0101] As shown in FIGS. 9 and 13, it is preferable that the radial cross-sectional shape of the fixture 25 at the proximal end 43B of the proximal end side portion 43 of the second section 40 is the same as the radial cross-sectional shape of the fixture 25 at the proximal end 33B of the proximal end side portion 33 of the first section 30. By setting the shape of the fixture 25 in the first section 30 and the second section 40 in this way, the manufacture of the fixture 25 becomes easier.

[0102] On the tip side of the first section 30 of the fixture 25, a function for ensuring easy insertion of the fixture 25 into the cylindrical body 10 is preferably imparted, and on the base end side of the first section 30, a function for firmly fixing the fixture 25 to the cylindrical body 10 is preferably imparted. Also, the second section 40 is imparted with a function for firmly fixing the fixture 25 to the cylindrical body 10. In order to enjoy both the effect of easy insertion of the fixture 25 into the cylindrical body 10 and the effect of firmly fixing the fixture 25 to the cylindrical body 10, in the direction x from the tip 25A to the base end 25B of the fixture 25, the lengths of the first section 30 and the second section 40 can be made different.

[0103] Figures 16 to 17 show side views representing modified examples of the fixture shown in Figure 8. As shown in Figure 16, in the direction x from the tip 25A to the base end 25B of the fixture 25, the first section 30 is preferably longer than the second section 40. Thereby, easy insertion of the fixture 25 into the cylindrical body 10 can be ensured.

[0104] As shown in Figure 17, in the direction x from the tip 25A to the base end 25B of the fixture 25, the first section 30 is preferably shorter than the second section 40. Thereby, the fixture 25 is more likely to be firmly fixed to the cylindrical body 10.

[0105] The surface roughness of the base end side portion 43 of the second section 40 is preferably greater than the surface roughness of the tip side portion 41 of the second section 40. Thereby, when the base end side portion 43 of the second section 40 of the fixture 25 abuts against the inner wall 11A of the first inner cavity 11 of the cylindrical body 10, an appropriate frictional resistance can be generated. Note that the surface roughness of the second section 40 can be measured in the same manner as the first section 30.

[0106] Figures 18 and 19 respectively show a perspective view and a side view representing a modified example of the fixture 25 shown in Figure 6. Figures 20 to 22 respectively show cross-sectional views in the radial direction at the base end 43B of the base end side portion 43 of the second section 40 of the fixture 25 shown in Figure 19, the tip 43A of the base end side portion 43, and the base end 41B of the tip side portion 41.

[0107] As shown in FIGS. 20 to 21, it is preferable that the contour 44 of the radial cross-sectional shape of the fixture 25 at the base end 43B of the base end side portion 43 of the second section 40 and the contour 44 of the radial cross-sectional shape of the fixture 25 at the tip end 43A of the base end side portion 43 both include a corner portion 45. Thereby, in the second section 40, the fixture 25 is likely to come into contact so as to be deeply bitten by the inner wall 11A of the cylindrical body 10. Although not shown, it is preferable that the contour 44 of the radial cross-sectional shape of the fixture 25 includes a corner portion 45 throughout the base end side portion 43 of the second section 40.

[0108] As shown in FIGS. 20 to 21, the radial cross-sectional shape of the fixture 25 may be the same between the base end 43B of the base end side portion 43 of the second section 40 and the tip end 43A of the base end side portion 43. Here, the fact that the cross-sectional shapes are the same means that the types of the cross-sectional shapes are the same, and those in which these shapes are similar to each other are also included.

[0109] Although not shown, the radial cross-sectional shape of the fixture 25 may be rotationally symmetric between the base end 43B of the base end side portion 43 of the second section 40 and the tip end 43A of the base end side portion 43. In that case, it is preferable that the tip of the corner portion 45 at the base end 43B of the base end side portion 43 of the second section 40 and the tip of the corner portion 45 at the tip end 43A of the base end side portion 43 are arranged at different positions in the circumferential direction of the fixture 25. By positioning the corner portion 45 in this way, the fixture 25 is more firmly fixed to the cylindrical body 10.

[0110] As shown in FIG. 22, the radial cross-sectional shape of the fixture 25 at the base end 41B of the tip end side portion 41 of the second section 40 is a quadrangular shape. For this reason, in the aspect shown in FIG. 22, the base end 41B of the tip end side portion 41 of the second section 40 also has a function of fixing the fixture 25 to the cylindrical body 10.

[0111] As shown in FIGS. 20 and 22, the radial cross-sectional shape of the fixture 25 may be the same at the base end 41B of the distal end side portion 41 of the second section 40 and the base end 43B of the proximal end side portion 43 of the second section 40. Further, the radial cross-sectional shape of the fixture 25 may be the same at the base end 41B of the distal end side portion 41 of the second section 40 and the tip 43A of the proximal end side portion 43 of the second section 40. In this way, the radial cross-sectional shape of the fixture 25 may be the same at any location in the second section 40. By making the cross-sectional shape the same in this way, it becomes easier to form the second section 40 of the fixture 20.

[0112] Furthermore, it is preferable that the fixture 25 has a third section 50 on the proximal end 25B side of the first section 30. The maximum outer diameter of the third section 50 is preferably smaller than the outer diameter of the proximal end of the first section 30. By providing the third section 50 on the proximal end 25B side of the fixture 25, stress concentration at the joint between the fixture 25 and the wire 20 can be prevented, so that kinking of the wire 20 can be suppressed.

[0113] The third section 50 is preferably arranged adjacent to the first section 30 or the second section 40. When the third section 50 is adjacent to the second section 40, the position where the outer diameter of the fixture 25 changes stepwise can be set as the boundary between the second section 40 and the third section 50. Also, when the third section 50 is adjacent to the first section 30, the position where the outer diameter of the fixture 25 changes stepwise can be set as the boundary between the first section 30 and the third section 50.

[0114] As long as kinking of the wire 20 can be suppressed, the maximum outer diameter of the fixture 25 in the third section 50 may be smaller than the inner diameter of the inner cavity of the cylindrical body 10. On the other hand, at least a part of the third section 50 may be in contact with the inner wall 11A of the first inner cavity 11. The maximum outer diameter of the fixture 25 in the third section 50 may be larger than the maximum diameter of the first inner cavity 11 of the cylindrical body 10. Thereby, a function for fixing the third section 50 of the fixture 25 to the cylindrical body 10 is also imparted.

[0115] In the third section 50, it is preferable that the radial cross-sectional area of the fixture 25 is substantially the same in the direction x from the distal end 25A to the proximal end 25B, or decreases toward the proximal end 25B side. Thereby, kinking of the wire 20 on the proximal end 25B side of the fixture 25 can be suppressed.

[0116] In the direction x from the distal end 25A to the proximal end 25B of the fixture 25, the lengths of the first section 30, the second section 40, and the third section 50 are not particularly limited and may be the same or different. Since mainly the first section 30 and the second section 40 contribute to the fixation to the cylindrical body 10, at least one of the first section 30 and the second section 40 may be longer than the third section 50.

[0117] The fixture 25 can be made of the same resin as the cylindrical body 10 or the same metal as the wire 20. It is preferable that the Rockwell hardness of the material constituting the wire 20 and the Rockwell hardness of the material constituting the fixture 25 are different from each other. More preferably, the Rockwell hardness of the material constituting the wire 20 is greater than the Rockwell hardness of the material constituting the fixture 25. By setting the hardness of the wire 20 and the fixture 25 in this way, while ensuring the elasticity of the wire 20, the surface processing of the fixture 25 can be facilitated. For example, the wire 20 can be made of SUS304 which is easy to obtain elasticity, and the fixture 25 can be made of SUS303 which has excellent machinability. Further, the fixture 25 can contain an X-ray non-permeable material. Thereby, it becomes easier to grasp the position of the treatment instrument 1 under X-ray fluoroscopy.

[0118] The method for fixing the fixture 25 to the wire 20 is not particularly limited, and methods such as caulking, welding, and adhesion can be used. For example, when the fixture 25 has a lumen 26 that penetrates from its tip 25A to its base 25B, the wire 20 can be inserted into the lumen 26, and the fixture 25 can be fixed to the tip of the wire 20 by using the above fixing method. In Fig. 8, a tip chip 21 having an outer diameter larger than the maximum diameter of the lumen 26 of the fixture 25 is provided at the tip of the wire 20. The tip of the wire 20 is inserted from the base of the lumen 26 of the fixture 25, and the fixture 25 is attached to the wire 20 by hooking the tip chip 21 on the tip 25A of the fixture 25. In order to fix the wire 20 and the fixture 25 more firmly, the tip chip 21 may be further heated and welded. When the materials of the fixture 25 and the wire 20 are metals, the fixing method of the fixture 25 and the wire 20 is preferably laser welding. Although not shown, without providing the tip chip 21 at the tip of the wire 20, the tip of the wire 20 is exposed from the tip 25A side of the fixture 25, and the tip of the wire 20 and the tip 25A of the fixture 25 are welded to each other to fix the wire 20 and the fixture 25. The tip chip 21 can be made of the same material as the fixture 25.

[0119] The configuration on the operator side for moving the treatment instrument 1 will be described. The operation handle 65 may have a first handle 66 connected to the proximal end portion of the wire 20 and a second handle 68 connected to the proximal side of the cylinder 10. In FIG. 1, the first handle 66 is provided outside the second handle 68. The first handle 66 is configured to be movable in the longitudinal direction with respect to the second handle 68. By moving the first handle 66 distally or proximally, the length and the degree of deflection of the portion of the wire 20 exposed from the cylinder 10 can be changed. The cylinder 10 and the second handle 68 are connected via a separate connection tube 60, and the tube 60 is provided with a first inlet 61 for inserting a guide wire. The second handle 68 is provided with a second inlet 67 for introducing a liquid into the second inner cavity 12 or the third inner cavity 13 of the cylinder 10. Further, the first handle 66 is provided with a connection portion 69 to a high-frequency power source. The cylinder 10 and the second handle 68, or the wire 20 and the first handle 66 may be directly connected to each other, or may be connected via another member such as the tube 60. These can be connected by methods such as thermocompression bonding and adhesion with an adhesive.

[0120] This application claims the benefit of priority based on Japanese Patent Application No. 2020-38076 filed on March 5, 2020. The entire contents of the specification of Japanese Patent Application No. 2020-38076 filed on March 5, 2020 are incorporated herein by reference.

Description of Reference Numerals

[0121] 1: High-frequency treatment instrument 5: Insertion portion 8: Curved portion 10: Cylinder, 11: First inner cavity, 11A: Inner wall of the first inner cavity, 12: Second inner cavity, 13: Third inner cavity, 14: First opening, 15: Second opening, 16: Third opening, 17: Fourth opening, 18: Fifth opening 20: Wire 21: Tip 25: Fixture, 25A: Tip of the fixture, 25B: Base end of the fixture, 26: Inner cavity of the fixture 30: First section, 31: Tip side part, 31A: Tip of the tip side part, 31B: Base end of the tip side part, 32: Central part, 33: Base end side part, 33A: Tip of the base end side part, 33B: Base end of the base end side part 34: Contour, 34A: Straight line part, 34B: Curve part, 35: Corner part, 36A: First flat surface part, 36B: Second flat surface part, 37A: Normal direction, 37B: Normal direction, 38: Edge part, 39: Circumscribed circle 40: Second section, 41: Tip side part, 41A: Tip of the tip side part, 41B: Base end of the tip side part, 42: Central part, 43: Base end side part, 43A: Tip of the base end side part, 43B: Base end of the base end side part 44: Contour, 44A: Straight line part, 44B: Curve part, 45: Corner part, 46A: First flat surface part, 46B: Second flat surface part, 47A: Normal direction, 47B: Normal direction, 48: Edge part, 49: Circumscribed circle, 50: Third section 60: Connecting tube, 61: First inlet, 65: Operation handle, 66: First handle, 67: Second inlet, 68: Second handle, 69: Connection part

Claims

1. a cylinder having a distal end and a proximal end, and having at least a first lumen and a second lumen inside; a wire made of metal having a tip end and a base end, partially exposed outside the cylinder on the distal side of the cylinder, and the other part disposed in the first lumen; a fixture fixed to the tip end of the wire, in contact with the inner wall of the first lumen, and having a tip end and a base end; the fixture has at least a first section that does not include a portion where the outer diameter increases toward the tip end side and includes a portion where the outer diameter decreases toward the tip end side; the fixture has a frustum-shaped portion in the portion where the outer diameter decreases toward the tip end side; when the first section is equally divided into a tip end side portion, a central portion, and a base end side portion, the radial cross-sectional shape of the fixture is different between the base end of the tip end side portion of the first section and the base end of the base end side portion of the first section; a high-frequency treatment instrument, wherein the contour of the radial cross-sectional shape of the fixture at the base end of the base end side portion of the first section includes a straight line portion. Here, the tip end of the wire and the tip end of the fixture refer to the side away from the user's hand among one end in the longitudinal axis direction of the wire, and the base end of the wire and the base end of the fixture are the ends on the side opposite to the tip end in the longitudinal axis direction of the wire.

2. The high-frequency treatment instrument according to claim 1, wherein the contour of the radial cross-sectional shape of the fixture at the base end of the base end side portion of the first section includes two straight line portions intersecting each other.

3. On the outer surface of the base end side portion of the first section of the fixture, a first flat portion and a second flat portion intersecting each other are formed, and the normal direction of the first flat portion and the normal direction of the second flat portion are different from the direction from the tip end to the base end of the fixture, respectively. The high-frequency treatment instrument according to claim 1 or 2.

4. The high-frequency treatment instrument according to any one of claims 1 to 3, wherein the contour of the radial cross-sectional shape of the fixture at the base end of the tip end side portion of the first section is composed only of a curved portion.

5. The high-frequency treatment instrument according to any one of claims 1 to 4, wherein the outer diameter of the radial cross-sectional shape of the fixture at the tip end of the base end side portion of the first section is larger than the maximum diameter of the first lumen.

6. The radial cross-sectional shape of the fixture at the proximal end of the distal end side portion of the first section is circular or oval, and the radial cross-sectional shape of the fixture at the proximal end of the proximal end side portion of the first section is polygonal. The high-frequency treatment instrument according to any one of claims 1 to 5.

7. The first section includes a portion with a constant outer diameter located on the proximal end side and a portion with an outer diameter that decreases toward the distal end side located on the distal end side. The high-frequency treatment instrument according to any one of claims 1 to 6.

8. Furthermore, the fixture has a second section located on the proximal end side of the fixture relative to the first section, including at least a portion with an outer diameter that decreases toward the distal end side and not including a portion with an outer diameter that increases toward the distal end side. The outer diameter of the distal end of the second section of the fixture is smaller than the outer diameter of the proximal end of the first section. The high-frequency treatment instrument according to any one of claims 1 to 7.

9. When the second section is divided into three equal parts: a distal end side portion, a central portion, and a proximal end side portion, the outer diameter of the radial cross-sectional shape of the fixture at the distal end of the proximal end side portion of the second section is larger than the maximum diameter of the first inner cavity. The high-frequency treatment instrument according to claim 8.

10. When the second section is divided into three equal parts: a distal end side portion, a central portion, and a proximal end side portion, the radial cross-sectional shape of the fixture is different at the proximal end of the distal end side portion of the second section and the proximal end of the proximal end side portion of the second section. The high-frequency treatment instrument according to claim 8 or 9.

11. The radius of the circumscribed circle of the radial cross-sectional shape of the fixture at the proximal end of the proximal end side portion of the second section is greater than or equal to the radius of the circumscribed circle of the radial cross-sectional shape of the fixture at the proximal end of the proximal end side portion of the first section. The high-frequency treatment instrument according to claim 10.

12. The radial cross-sectional shape of the fixture at the proximal end of the proximal end side portion of the second section is the same as the radial cross-sectional shape of the fixture at the proximal end of the proximal end side portion of the first section. The internal high-frequency treatment instrument according to claim 10 or 11.

13. In the direction from the distal end to the proximal end of the fixture, the length of the first section is different from that of the second section. The high-frequency treatment instrument according to any one of claims 8 to 12.

14. In the second section, the fixture is formed in a frustum shape. The high-frequency treatment instrument according to any one of claims 8 to 13.

15. The high-frequency treatment instrument according to any one of claims 8 to 14, wherein the surface roughness of the proximal end side portion of the second section is greater than the surface roughness of the distal end side portion of the second section. Note that the surface roughness is the arithmetic mean roughness Ra between the reference lengths of the roughness curve in the circumferential direction of the surface of the fixture, and the reference length is one-fourth of the circumferential length of the fixture at each measurement position.

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