JP2002263112A - Snare for endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a snare which enables a snare loop to maintain an initial spread without the occurrence of a 'permanent set by fatigue' of an elastic wire in the distal end portion of the snare loop even if the expansion and contraction of the snare loop are repeated. SOLUTION: The elastic wire 11 is wound like a coil in a range of 1.5 to 2 turns in the distal end portion 12 of the snare loop 10 and is bent therefrom in the direction where the snare loop 10 is formed.

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 which is used for cutting a polyp through a treatment tool insertion channel of the endoscope.

[0002]

2. Description of the Related Art As shown in FIG. 4, a snare for an endoscope generally has a snare loop 10 formed by bending an elastic wire 11 and is inserted through a flexible sheath 1 so as to be able to advance and retreat in the axial direction. The snare loop 10 is moved in and out of the distal end of the flexible sheath 1 by moving the operating wire 2 forward and backward in the axial direction. In this case, the elastic wire 11 expands due to the elasticity of the elastic wire 11, and when it is drawn into the flexible sheath 1, it is elastically deformed and narrows.

In such a snare for an endoscope, when the snare loop 10 expands and contracts, the elastic wire 11 is greatly deformed at the tip of the snare loop 10, so that plastic deformation occurs in that portion and the so-called crumpled state occurs. As a result, the spread of the snare loop 10 tends to be reduced as indicated by the two-dot chain line.

Therefore, in the snare for an endoscope shown in, for example, Japanese Utility Model Application Laid-Open No. 3-31412, the deformation range of the distal end portion 12 when the snare loop 10 expands and contracts is increased.
The elastic wire 11 is rotated once at the tip of the snare loop 10 and then extends in the direction in which the snare loop 10 is formed.

[0005]

However, even if the elastic wire 11 is rotated once at the tip of the snare loop 10 as described above, the expansion and contraction of the snare loop 10 using the snare for an endoscope is not considered. Repeatedly, the tip portion 12
Cannot prevent the elastic wire 11 from sagging,
The spread of the snare loop 10 is reduced.

Accordingly, the present invention provides a method of the present invention that does not cause the elastic wire to "set" at the distal end portion of the snare loop even if the snare loop is repeatedly expanded and contracted, and that the snare loop can maintain its original spread. An object of the present invention is to provide a snare for an endoscope.

[0007]

In order to achieve the above object, a snare for an endoscope according to the present invention has a snare loop formed by bending an elastic wire, which is inserted through a sheath so as to be able to advance and retreat in the axial direction. The snare loop moves into and out of the distal end of the sheath by moving the operating wire back and forth in the axial direction, and the snare loop expands outside the sheath due to the elasticity of the elastic wire and retracts into the sheath. In an endoscope snare which is elastically deformed and narrowed when it is wound, an elastic wire is wound in a coil shape in a range of 1.5 to 2 turns at a tip portion of the snare loop,
From there, it is bent in a direction to form a snare loop.

It is most preferable that the number of windings of the elastic wire at the tip of the snare loop is in the range of 1.7 to 1.8 turns.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an endoscope snare according to an embodiment of the present invention. Reference numeral 1 denotes a flexible sheath made of, for example, an electrically insulating tube made of tetrafluoroethylene resin. It is inserted into and removed from the treatment instrument insertion channel of the endoscope.

An operation wire 2 made of a flexible conductive metal is inserted through the entire length of the flexible sheath 1 so as to be able to advance and retreat in the axial direction. Arbitrary operation is performed.

A snare loop 10 formed by bending a single conductive elastic wire 11 into a loop is connected to a distal end portion of the operation wire 2 via a connection pipe 3.
A high-frequency current can be supplied to the snare loop 10 via the operation wire 2.

Elastic wire 1 forming snare loop 10
As 1, for example, a single wire or a stranded wire of a stainless steel wire is used. Further, the operation wire 2 may be formed by extending the elastic wire 11.

When no external force is applied outside the flexible sheath 1, the snare loop 10
As shown in FIG. 1, a loop extending several centimeters is formed by the elasticity of 1 and can be engaged with a polyp or the like in this state.

When the operation wire 2 is pulled toward the user, the snare loop 10 is pulled into the flexible sheath 1 as shown in FIG.
Is elastically deformed and the snare loop 10 narrows, and in this state, the snare loop 10 can be inserted into and removed from the treatment instrument insertion channel of the endoscope.

When the polyp is excised, the operation wire 2 is pulled toward the user's hand while the polyp is surrounded by the snare loop 10 which is widened as shown in FIG.
Tighten the polyp with snare loop 10 and elastic wire 1
When a high-frequency current is applied to 1, the polyp is cauterized and cut. However, it may be mechanically cut.

At the distal end portion 12 of the snare loop 10 of this embodiment, as shown in an enlarged view in FIG. 3, an elastic wire 11 is wound in a coil shape in a range of 1.7 to 1.8 turns. It is bent and extended in the direction in which the snare loop 10 is formed.

Therefore, when the snare loop 10 expands / contracts, the elastic wire 11 is elastically deformed in the coiled range of 1.7 to 1.8 turns at the tip portion 12 of the snare loop 10, so that the snare loop is formed. Even if the expansion and contraction of the loop 10 is repeated, the elastic wire 11 does not sag, and the snare loop 10 can maintain the initial expansion.

However, the tip portion 12 of the snare loop 10
It is sufficient that the number of turns of the elastic wire 11 is in the range of 1.5 to 2 turns, and if it is 2 turns or more, the thickness of the portion becomes large, so that it is difficult to be pulled into the flexible sheath 1 and 1.5 turns In the following, there is a possibility that the expanding shape in the direction of the snare loop 10 becomes unnatural and the expanding / contracting operation is not smooth.

When the polyp is tightened by the snare loop 10 configured as described above, the rear outer surface of the tip portion 12 formed in a coil shape comes into contact with the polyp, and the polyp is cut off at that portion, so that the polyp is torn. It can be cut in a good condition without any.

Further, by forming the distal end portion 12 of the snare loop 10 into a coil shape, the length of the distal end portion 12 is extremely short, so that when the polyp is subjected to high-frequency ablation, the distal end portion 12 of the snare loop 10 is formed. Less risk of burns by touching surrounding mucous membranes.

[0021]

According to the present invention, the elastic wire is wound in a coil shape in the range of 1.5 to 2 turns at the tip portion of the snare loop, and is bent therefrom in a direction to form the snare loop. Thereby, even if the expansion and contraction of the snare loop are repeated, "sag" does not occur in the elastic wire at the tip of the snare loop, and the initial spread of the snare loop can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is a partial plan sectional view of an endoscope snare according to an embodiment of the present invention, in which a snare loop is expanded.

FIG. 2 is a plan partial cross-sectional view of the endoscope snare of the embodiment of the present invention, in which a snare loop is narrowed.

FIG. 3 is a partial perspective view of a tip portion of a snare loop of the endoscope snare according to the embodiment of the present invention.

FIG. 4 is a partial plan sectional view of a conventional endoscope snare with a snare loop expanded.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible sheath 2 Operation wire 10 Snare loop 11 Elastic wire 12 Tip part

Claims (2)

[Claims] A snare loop formed by bending an elastic wire is connected to a distal end of an operation wire inserted and disposed in a sheath so as to be able to advance and retreat in an axial direction, and by operating the operation wire in an axial direction. The endoscope in which the snare loop enters and exits the distal end of the sheath, and the snare loop expands outside the sheath due to the elasticity of the elastic wire, and is elastically deformed and contracted when retracted into the sheath. In the snare, the elastic wire is wound in a coil shape at a tip portion of the snare loop in a range of 1.5 to 2 turns, and is bent therefrom in a direction to form the snare loop. Snare for endoscope. 2. A snare for an endoscope according to claim 1, wherein said elastic wire is wound in a coil shape in a range of 1.7 to 1.8 turns at a tip portion of said snare loop.