JP3231667B2 - Wire loop type treatment instrument for endoscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention is for an endoscope wire loop procedures such as high-frequency snare again and again relates.

[0002]

2. Description of the Related Art As shown in FIG. 4, a wire loop type treatment instrument for an endoscope such as a high-frequency snare is generally bent back into a U-shape at a tip and bulged in a loop at a rear portion thereof. The elastic wire 10 composed of a stranded wire formed into a shape is narrowed by being drawn into the distal end of the sheath 20, and expands in a loop shape by its own elasticity when protruding from the distal end of the sheath 20. .

[0003] The elastic wire used therein is
A so-called 1 × 7 twisted wire obtained by twisting seven strands 11 made of a stainless steel wire having a diameter of about 0.1 mm to 0.15 mm and having a circular cross section is widely used. FIG. 5 shows the cross-sectional shape.

In addition to the 1 × 7 strand, 1 × 3 strand of three strands, 1 × 19 strand of 19 strands, and 1 × 37 strand of 37 strands Twist and the like are also used.

[0005]

FIG. 6 shows an elastic wire 10 composed of a 1 × 7 stranded wire. When the elastic wire 10 is bent back into a U-shape as shown by a two-dot chain line, FIG. As shown in FIG. 7, the individual wires 11 are loosened and deformed irregularly, resulting in an irregular arrangement.

As a result, the bent-back portion expands and cannot be pulled into the sheath 20, and when the polyp or the like is tightened during use, it tends to be cut due to stress concentration or Joule heat due to high-frequency current. In addition, the appearance is poor and the commercial value is reduced.

[0007] Therefore, the present invention provides a method of forming an elastic wire into a stranded wire smoothly without loosening the stranded wire at the end of the loop.
An object of the present invention is to provide a wire loop-type treatment instrument for an endoscope that can be bent back into a letter shape and a method for manufacturing the same.

[0008]

In order to achieve the above object, a wire loop treatment device for an endoscope according to the present invention is bent back into a U-shape and formed into a loop-shaped bulge at a rear portion thereof. An endoscope wire loop in which an elastic wire formed of a stranded wire is narrowed by being drawn into the distal end of the sheath, and expands into the loop shape by its own elasticity in a state where the elastic wire protrudes from the distal end of the sheath. In the type treatment instrument, each strand of the stranded wire forming the elastic wire is formed in a non-circular cross-sectional shape that is hard to bend in other directions as compared to a direction toward the center of the elastic wire. I do.

The cross section of the wire of the elastic wire is close to a trapezoid, and a portion corresponding to the bottom is located on the outer surface side, and adjacent wires are opposed to each other on the side surfaces of the trapezoid. Is also good.

Further, in the method of manufacturing a wire loop type treatment instrument for an endoscope according to the present invention, the device is retracted into the distal end of the sheath, and when it protrudes from the distal end of the sheath, forms a loop by its own elasticity. A method for manufacturing a wire loop-type treatment instrument for an endoscope having an elastic wire made of a stranded wire formed by bending a U-shaped end portion at its distal end so as to swell and bulging into a loop at the rear portion. In the elastic wire, a stranded wire formed by twisting a plurality of wires having a circular cross section is passed through a die having a diameter smaller than the diameter of the stranded wire, so that each of the wires has a non-circular cross-sectional shape. It is characterized by being formed by compression deformation.

The cross section of the wire of the elastic wire after passing through the die has a shape close to a trapezoid, a portion corresponding to the bottom is located on the outer surface side, and the adjacent wire is the trapezoid. May face each other.

The diameter of the die is 8 to 10.5% as compared with the diameter of the stranded wire before passing through the die.
The elastic wire may have a diameter of 0.1 m.
a 1 × 7 stranded wire having a diameter of 0.276 mm and a diameter of the elastic wire of 0.276 after being passed through the die.
It may be 0.552 mm.

[0013]

Embodiments of the present invention will be described with reference to the drawings. FIG. 4 shows a distal end portion of a high-frequency snare for an endoscope. Reference numeral 20 denotes a flexible sheath made of, for example, a tetrafluoroethylene resin tube, which is inserted into a treatment tool insertion channel of an endoscope (not shown). It is inserted and removed.

A conductive operation wire 30 is inserted in the sheath 20 so as to be able to advance and retreat in the axial direction.
Is operated by an operation unit (not shown) connected to the base end of the camera.

An elastic wire 10 formed to have a predetermined loop shape in a natural state is connected to a distal end of the operation wire 30 via a connecting pipe 40. The distal end of the elastic wire 10 and the proximal end of the sheath 20 are inserted into the connecting pipe 40 from the front and the rear, and are fixed by silver brazing or the like.

The elastic wire 10 is a single stranded wire made of stainless steel wire, is bent back into a U-shape at a bent back portion 10a at the tip, and is bent so as to form a loop at a rear portion thereof. I have.

As a result, when the elastic wire 10 protrudes from the distal end of the sheath 20, it expands in a loop shape due to its own elasticity. When the elastic wire 10 is pulled backward (hand side) by the operating wire 30, it is pulled into the distal end of the sheath 20. And contracted.

In this embodiment, the elastic wire 1
The two wires that have been bent back at zero are bent at the three bent portions 10b, 10c, and 10d, but the number of bends may be different, and the wires are bent in a curved shape without being bent. May be.

In this embodiment, as the elastic wire 10, 1 × 7 strands of seven strands 11 of stainless steel wire having a circular cross section with a diameter of about 0.1 to 0.2 mm are stranded. Twisted stranded wires are used. Strand 11
Have the same diameter, seven are arranged straight in the center, and the other six are spirally wound around them.

However, the elastic wire 10 of the present invention does not use such a stranded wire as it is, but a so-called swaging process in which each strand 11 is compressed and deformed through a stranded wire having a diameter smaller than the diameter of the stranded wire. It has been subjected.

As a result, as shown in FIG. 1, the elastic wire 10 is plastically deformed in a direction in which the gap between the individual wires 11 is eliminated, and one of the seven wires 11 is hexagonal. The six strands 11 twisted around have a cross-sectional shape close to a trapezoid, with the bottom portion located on the outer surface side, and the side surfaces (slope of the trapezoid) facing each other. become.

As a result of the experiment, the degree of change in the diameter during the swaging processing is as follows: when the diameter before processing is D 'and the diameter after processing is D, (D'-D) / D' = 0.
08 to 0.105, and when the diameter of the wire 11 is 0.1 to 0.2 mm, the elastic wire 10
Has a diameter in the range of 0.276 to 0.552 mm.

As shown in FIG. 2, even if the elastic wire 10 subjected to the swaging process is bent back into a U-shape with a small radius of curvature, the wire 11 is very smooth without being loosened. Keep state.

This is, as shown in FIG.
1 has a characteristic that it is hard to bend in the other direction as compared with the direction R toward the center of the stranded wire forming the elastic wire 10 because the bottom portion is formed in a shape close to a trapezoid located on the outer surface side. It is considered that each of the wires 11 does not move in a direction deviating from the twisted state when being bent into a U-shape.

The present invention is not limited to the above-described embodiment. For example, the elastic wire 10 may be a 1 × 3 twisted wire other than a 1 × 7 twist wire as shown in FIG. Various stranded wires may be used, and the swaging process results in a cross-sectional shape in which each strand 11 of the stranded wire is less likely to bend in other directions as compared to the direction R toward the center of the elastic wire 10.

Further, the elastic wire 10 of the present invention has a non-circular wire 11 whose original cross-sectional shape is less likely to bend in the other direction as compared with the direction toward the center of the elastic wire 10 without using swaging. May be formed by twisting. Further, the present invention can be applied to various types of endoscope wire loop-type treatment tools that require a stranded wire to be bent into a U-shape with a small radius of curvature.

[0027]

According to the present invention, a stranded wire formed by twisting strands having a non-circular cross-sectional shape that is less likely to bend in the other direction than the direction toward the center of the stranded wire forming the elastic wire. The elastic wire can be smoothly bent back into a U-shape with a small radius of curvature without unraveling the wire at the tip of the loop, making it difficult to pull in the sheath or to use the elastic wire. A wire loop type treatment instrument for an endoscope can be formed which does not suffer from insufficient strength at the time and has a texture in appearance and has excellent commercial value.

[0028] Such an elastic wire is compressed and deformed into a non-circular cross-sectional shape by passing the strand through a die having a diameter smaller than the diameter of a strand obtained by twisting a plurality of strands having a circular cross section. By doing so, it can be easily formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view in a direction perpendicular to an axis of an elastic wire according to a first embodiment of the present invention.

FIG. 2 is a side view of a U-shaped portion of the elastic wire according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view in a direction perpendicular to an axis of an elastic wire according to a second embodiment of the present invention.

FIG. 4 is a side cross-sectional view of a distal end portion of the endoscope wire loop treatment tool.

FIG. 5 is a cross-sectional view in a direction perpendicular to an axis of an elastic wire used in a conventional wire loop treatment device for an endoscope.

FIG. 6 is a side view of an elastic wire used in a conventional wire loop treatment device for an endoscope.

FIG. 7 is a side view of a U-shaped portion of a conventional elastic wire.

[Explanation of symbols]

 10 elastic wire 11 strand

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-320931 (JP, A) JP-A-6-108388 (JP, A) JP-A-1-225006 (JP, A) 508284 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) A61B 17/00-18/28

Claims (2)

(57) [Claims] An elastic wire made of a stranded wire bent back into a U-shape and formed into a loop-shaped bulge at a rear portion thereof is narrowed by being drawn into the distal end of the sheath, and the sheath is closed. In the wire loop treatment device for an endoscope, which protrudes in a loop shape by its own elasticity in a state where it protrudes from the distal end, the elastic wire has six elastic wires around one straight element wire. and the strands are formed by spirally wound, with the cross-sectional shape of the straight wire above SL one is substantially equilateral hexagon, cross-section of the wires six present wrapped the spirally The shape is substantially trapezoidal, and a portion corresponding to each upper bottom thereof is opposed to each side of the single straight element wire, and adjacent elements are opposed to each other on the side surfaces of the trapezoid. Endoscope wire loop processing Ingredients. 2. A method according to claim 1, wherein the elastic wire is formed by twisting seven strands having a circular cross section through a stranded wire having a diameter smaller than the diameter of the stranded wire. The wire loop treatment device for an endoscope according to claim 1, wherein the treatment device is formed by compressive deformation to a cross-sectional shape.