JP3974232B2 - Endoscope snare - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an endoscopic snare used for performing polypectomy or the like in a body cavity via an endoscope.
[0002]
[Prior art]
FIG. 6 shows a conventional endoscope snare, in which an elastic wire 1 forming a loop is bent back in a U shape at the distal end and bound at the proximal end, and the loop is connected to the distal end of the sheath 2. It is constricted by being pulled in, and inflated by its own elasticity in a state of protruding from the distal end of the sheath 2.
[0003]
Such an endoscopic snare may use two material wires as the elastic wire 1 and fix and bind them at the tip. However, since the whole spring property is increased by adopting a configuration in which the tip is bent back into a U shape, the loop size is reduced after the loop is constricted and expanded (so-called “sag”). ) Is suppressed, and durability quality is improved.
[0004]
[Problems to be solved by the invention]
However, even in such an endoscopic snare, as shown in FIG. 7, when the elastic wire 1 is drawn into the distal end of the sheath 2 and the loop is constricted, the distal end bending return portion 1a In addition, a considerably large deformation occurs in the bent portion 1b or the like that moves from the tip to the loop portion.
[0005]
Therefore, during repeated use, the elastic wire 1 is plastically deformed at the portions 1a and 1b, and the loop size is gradually reduced as shown in FIG. 8, so that the function as an endoscope snare is reduced. Resulting in.
[0006]
Accordingly, an object of the present invention is to provide an endoscopic snare that is small in the degree of reduction in loop size even when used repeatedly and can maintain a good function for a long period of time.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the endoscopic snare according to the present invention is formed in a shape that is bent back at the distal end and bound at the proximal end to form a loop as a whole, and can be freely inserted and removed from the distal end of the sheath. In an endoscopic snare in which the wire is narrowed by being drawn into the distal end of the sheath and protrudes from the distal end of the sheath so as to swell in a loop shape by its own elasticity, the distal end of the elastic wire is bent The return portion is formed in a C shape.
[0008]
The elastic wire may be bent a plurality of times at a portion where the C-shaped tip bent-back portion transitions to the loop portion, and in that case, the elastic wire is inserted between the plurality of bent portions. The shape may be widened toward the loop portion side, the plurality of bent portions may be provided at two locations, and the elastic wires may be disposed in parallel between the two bent portions.
[0009]
The elastic wire may be formed in a shape in which arc-shaped curves are joined from a C-shaped tip bent back portion to a portion that transitions to the loop portion.
[0010]
[Form of the present invention]
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a distal end portion of an endoscopic snare to which the present invention is applied. In order to fasten a polyp or the like by a single elastic wire 10 bent back at the distal end portion and bound together at the proximal end. The loop is formed. As the elastic wire 10, for example, a stranded wire obtained by twisting thin stainless steel wires or a single wire of stainless steel wire is used.
[0011]
The tip bending return portion 11 is bent in an arc shape and is formed in a C shape. And in the part which transfers to a loop part from there, it is bent outward in order in two places, the 1st bending part 12 and the 2nd bending part 13 which were formed close. In a portion between the first bent portion 12 and the second bent portion 13, the elastic wire 10 has a shape that expands in a C shape toward the loop portion side.
[0012]
The loop is widest between the third bent portion 14 and the fourth bent portion 15 apart from the second bent portion 13, and is bent inward from the fourth bent portion 15. Thus, the proximal end bundling portion side is inserted into the distal end portion of the sheath 20.
[0013]
The proximal end portions of the pair of elastic wires 10 are inserted into the connecting pipe 30 in the sheath 20 and fixed and bound by silver brazing or the like. The tip 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.
[0014]
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 instrument insertion channel of an endoscope (not shown) in use.
[0015]
The operation wire 40 is inserted into the sheath 20 so as to be movable forward and backward in the axial direction together with the connection pipe 30, and is advanced and retracted by an operation portion (not shown) connected to the proximal end portion of the sheath 20, thereby being elastic. The wire 10 enters and exits the distal end of the sheath 20.
[0016]
As shown in FIG. 1, the elastic wire 10 swells in a loop shape due to its own elasticity in a state in which most of the elastic wire 10 is pushed out from the distal end of the sheath 20. As shown in FIG. 2, when pulled by the operation wire 40 and pulled into the sheath 20, each part of the elastic wire 10 is elastically deformed and becomes a narrowed shape.
[0017]
The use of the snare for an endoscope repeats the state in which the elastic wire 10 bulges and the state in which the snare is squeezed as described above. In such an operation, in the present embodiment, since the tip bending return portion 11 is formed in a C-shape, the arc-shaped portion is longer than the U-shape. (Torsion spring) is high and plastic deformation is difficult.
[0018]
In addition, since the two bent portions of the first bent portion 12 and the second bent portion 13 are provided and gradually spread in the portion that transitions from the tip bent-back portion 11 to the loop-shaped portion, there is one place. The change in the bending angle at the bent portion is halved compared to the case where there is only one bent portion, and this portion is also difficult to plastically deform.
[0019]
Therefore, the endoscope snare according to this embodiment is excellent in that the loop bend size is not reduced because the distal end bent-back portion 11 and the first and second bent portions 12 and 13 are hardly plastically deformed even when used repeatedly. Function can be maintained over a long period of time.
[0020]
FIG. 3 shows the distal end portion of the endoscope snare according to the second embodiment of the present invention, and the loop portion after the second bent portion 13 of the elastic wire 10 is formed into an arc-shaped smooth curve. The other parts are the same as those of the first embodiment. Illustration of the sheath 20 is omitted.
[0024]
Note that the endoscope snare of the present invention may be capable of passing a high-frequency current through the elastic wire 10 via the operation wire 40, or may simply mechanically tighten a polyp or the like with the elastic wire 10. Also good.
[0025]
【The invention's effect】
According to the present invention, since the bent end portion of the elastic wire forming the loop is formed in a C-shape, the spring property of the bent back portion is increased, and the plastic deformation is caused even if the insertion into and removal from the sheath is repeated. Therefore, the degree of reduction of the loop size is small, and a good function can be maintained over a long period.
[Brief description of the drawings]
FIG. 1 is a side cross-sectional view of a tip portion in a state where a loop is formed by an elastic wire according to a first embodiment of the present invention.
FIG. 2 is a side cross-sectional view of the distal end portion in a state where the elastic wire according to the first embodiment of the present invention is constricted.
FIG. 3 is a side view showing a state in which the elastic wire according to the second embodiment of the present invention forms a loop.
FIG. 4 is a side cross-sectional view of a distal end portion of a conventional endoscope snare with a loop formed by an elastic wire .
FIG. 5 is a side cross-sectional view of a distal end portion of a conventional endoscope snare in a state where an elastic wire is narrowed .
FIG. 6 is a side cross-sectional view of a distal end portion in a state where a loop is formed after repeated use of an elastic wire of a conventional endoscope snare.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Elastic wire 11 End bending return part 12 1st bending part 13 2nd bending part 16 Arc-shaped bending part

Claims (1)

An elastic wire which is bent back at the distal end and bound at the proximal end to form a loop as a whole and which can be freely inserted into and removed from the distal end of the sheath is narrowed by being drawn into the distal end of the sheath, and the sheath Endoscopic snare that bulges in the loop shape by its own elasticity in a state protruding from the tip of the
Two elastic wires bent back into an arc shape at the tip end are expanded without crossing or contacting each other from once in the direction of crossing to form the loop,
At the distal end position of the region where the two elastic wires are expanded without crossing or contacting each other once in the direction of crossing each other, the two elastic wires are respectively closed on the proximal side without closing the two elastic wires. A first bent portion is provided to bend into a shape that expands in a square shape toward the direction in which the loop is expanded, and is located at the rear end position of the portion that is formed in the shape that expands in a square shape. A snare for an endoscope characterized in that a second bent portion for bending each elastic wire in a direction in which the loop is further expanded is formed.

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