JPH1176251A - Snare for endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a snare for an endoscope in which the degree of contraction of a loop size is small even when it is repeatedly used and which can keep good function over a long period. SOLUTION: In a snare for an endoscope wherein an elastic wire 10 which is bent back at its apex and is bound at its base end and is formed into a loop shape as a whole and is arranged so as to be freely in and out from the apex of a sheath 20, is narrowed by being pulled into the apex of the sheath 20 and is expanded into a loop shape by its own elasticity under its projected condition from the apex of the sheath 20, the bent back part 11 at its apex of the elastic wire 10 is formed into a C-like shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a snare for an endoscope used for resecting polyps in a body cavity through an endoscope.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional snare for an endoscope.
It is bent back into a letter shape and bound at the proximal end, and its loop is narrowed by being drawn into the distal end of the sheath 2, and expands due to its own elasticity when it protrudes from the distal end of the sheath 2. I have.

In such a snare for an endoscope, two material wires may be used as the elastic wire 1 and fixed and bound at the distal end. However, by adopting a configuration in which the tip is bent back into a U-shape, the overall spring property is enhanced, so that the loop size is reduced after the loop has been repeatedly narrowed and expanded (so-called “slack”). ) Is suppressed, and the durability quality is improved.

[0004]

However, even with such a snare for an endoscope, as shown in FIG. 7, the elastic wire 1 is drawn into the distal end of the sheath 2 and the loop is narrowed. In this state, the front end bent back portion 1a and the bent portion 1b that transitions from the front end to the loop portion undergo considerable deformation.

Therefore, the elastic wire 1 is plastically deformed at the portions 1a and 1b during repeated use, and the loop size is gradually reduced as shown in FIG. Function is reduced.

Accordingly, an object of the present invention is to provide a snare for an endoscope in which the degree of reduction of the loop size is small even if it is repeatedly used, and which can maintain good functions for a long period of time.

[0007]

In order to achieve the above object, an endoscope snare according to the present invention is bent back at the distal end, bound at the proximal end, and formed into a loop shape as a whole. An endoscope in which an elastic wire arranged so as to be able to be taken in and out from the distal end is narrowed by being drawn into the distal end of the sheath, and expands in the loop shape by its own elasticity in a state of protruding from the distal end of the sheath. In the snare, the bent back portion of the elastic wire is formed in a C-shape.

[0008] The elastic wire may be bent a plurality of times at a portion transitioning from the C-shaped bent back portion to the loop portion. In this case, the elastic wire may be bent between the plurality of bent portions. The wire may have a shape spreading toward the loop portion side,
The plurality of bent portions may be provided at two positions, and the elastic wires may be arranged in parallel between the two bent portions.

Further, the elastic wire may be formed in a shape in which arc-shaped curves are connected from a C-shaped bent back portion to a portion where the loop portion transitions.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a distal end portion of an endoscope snare to which the present invention is applied, in which a single elastic wire 10 bent back at a distal end portion and bound together at a proximal end tightens a polyp or the like. Loop is formed. As the elastic wire 10, for example, a stranded wire obtained by twisting thin stainless steel wires or a single stainless steel wire is used.

The bent back portion 11 is bent in an arc shape and formed in a C-shape. Then, at a portion where the transition is made to the loop portion, the first bent portion 12 and the second bent portion 13 formed close to each other are sequentially bent outward. In a portion between the first bent portion 12 and the second bent portion 13, the elastic wire 1
0 has a shape spreading in a C shape toward the loop portion side.

The loop has the largest width between the third bent portion 14 and the fourth bent portion 15 distant from the second bent portion 13, and is inwardly extended from the fourth bent portion 15. The proximal binding portion is inserted into the distal end portion of the sheath 20.

The base ends of the pair of elastic wires 10 are inserted into a connecting pipe 30 in the sheath 20 and fixed and bound by silver brazing or the like. The distal end of the operation wire 40 is inserted from the opposite side of the connection pipe 30 and fixed by silver brazing or the like, and the elastic wire 10 and the operation wire 40 are connected via the connection pipe 30.

The sheath 20 is a flexible tube made of, for example, a tetrafluoroethylene resin tube or the like, and is inserted into and removed from a treatment tool insertion channel of an endoscope (not shown) at the time of use.

The operating wire 40 is inserted into the sheath 20 so as to be able to advance and retreat in the axial direction together with the connecting pipe 30.
An operation portion (not shown) connected to the proximal end of the sheath 20 is advanced and retracted, thereby the elastic wire 1
0 goes in and out of the distal end of the sheath 20.

When most of the elastic wire 10 is pushed out from the distal end of the sheath 20 as shown in FIG. 1, the elastic wire 10 has a shape bulging into a loop due to its own elasticity. Then, as shown in FIG. 2, when being pulled by the operation wire 40 and pulled into the sheath 20, each part of the elastic wire 10 is elastically deformed to have a narrowed shape.

In the endoscope snare, the state in which the elastic wire 10 swells and the state in which it contracts as described above are repeated. In the case of such an operation, in the present embodiment, since the tip bent-back portion 11 is formed in a C-shape, the arc-shaped portion is longer than the U-shape.
High spring property (torsional spring) against bending, making it difficult for plastic deformation.

Further, at the part which transitions from the front bent back part 11 to the loop part, two bent parts of a first bent part 12 and a second bent part 13 are provided and gradually expanded. The change in the bending angle at one bent portion is half that in the case where there is only one bent portion, and this portion is also less likely to be plastically deformed.

Therefore, in the snare for an endoscope of this embodiment, the loop size is reduced since the bent back end portion 11 and the first and second bent portions 12 and 13 are not easily plastically deformed even when used repeatedly. Without this, good functions can be maintained for a long period of time.

FIG. 3 shows a distal end portion of an endoscope snare according to a second embodiment of the present invention. The loop portion of the elastic wire 10 after the second bent portion 13 is formed into a smooth arc-shaped portion. It is formed into a curved line, and the other parts are the same as in the first embodiment. The illustration of the sheath 20 is omitted.

FIG. 4 shows a distal end portion of an endoscope snare according to a third embodiment of the present invention, in which a portion between a first bent portion 12 and a second bent portion 13 of an elastic wire 10 is shown. Is formed in parallel with the axis of the distal end portion of the sheath 20 in the same direction. Functionally, it is the same as the first embodiment.

FIG. 5 shows a distal end portion of an endoscope snare according to a fourth embodiment of the present invention. The first bent portion 12 and the second bent portion 13 in the first embodiment are shown.
Is replaced with one arc-shaped bent portion 16.

In this way, the elastic wire 10
Since there is no straight portion and the arc-shaped curve is joined from the character-shaped bent back portion 11 to the transition to the loop portion, the entire range acts as a torsion spring and the elastic limit is increased. , It is less likely to be plastically deformed.

The endoscope snare of the present invention may be one that can pass a high-frequency current through the elastic wire 10 through the operation wire 40, or one that simply mechanically tightens a polyp or the like with the elastic wire 10. It may be.

[0025]

According to the present invention, the bent back portion of the elastic wire forming the loop is formed in a C-shape, so that the spring portion of the bent back portion is enhanced, and the insertion and removal into and from the sheath are repeated. However, since plastic deformation is difficult, the degree of reduction in loop size is small, and good functions can be maintained for a long period of time.

[Brief description of the drawings]

FIG. 1 is a side cross-sectional view of a distal end portion of an elastic wire according to a first embodiment of the present invention in a state where a loop is formed.

FIG. 2 is a side sectional view of a distal end portion of the first embodiment of the present invention in a state where an elastic wire is narrowed.

FIG. 3 is a side view showing a state in which an elastic wire according to a second embodiment of the present invention forms a loop.

FIG. 4 is a partial side view of a bent back portion of an elastic wire according to a third embodiment of the present invention.

FIG. 5 is a partial side view of a bent back portion of an elastic wire according to a fourth embodiment of the present invention.

FIG. 6 is a side sectional view of a distal end portion of a conventional endoscope snare in a state where an elastic wire forms a loop.

FIG. 7 is a side sectional view of a distal end portion of a conventional endoscope snare in a state where an elastic wire is narrowed.

FIG. 8 is a side cross-sectional view of a distal end portion of a conventional endoscope snare in a state where a loop is formed after repeated use of an elastic wire.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 elastic wire 11 tip bent-back portion 12 first bent portion 13 second bent portion 16 arc-shaped bent portion

Claims (5)

[Claims] An elastic wire, which is bent back at the distal end, bound at the proximal end and formed into a loop as a whole, and is disposed so as to be freely inserted into and removed from the distal end of the sheath, is drawn into the distal end of the sheath. In the endoscope snare, which is swelled and swells in the form of a loop by its own elasticity in a state where it protrudes from the distal end of the sheath, a bent-back portion of the distal end of the elastic wire is formed in a C-shape. Endoscope snare. 2. A snare for an endoscope according to claim 1, wherein said elastic wire is bent a plurality of times at a portion transitioning from a C-shaped bent back portion to said loop portion. 3. The endoscope snare according to claim 2, wherein the elastic wire has a shape extending toward the loop portion between the plurality of bent portions. 4. A snare for an endoscope according to claim 2, wherein said plurality of bent portions are provided at two positions, and said elastic wire is disposed in parallel between said two bent portions. 5. A snare for an endoscope according to claim 1, wherein said elastic wire is formed by connecting arc-shaped curves from a C-shaped bent back portion to a portion transitioning to said loop portion. .