JP2021029277A - Endoscopic snare - Google Patents

Abstract

To provide an endoscopic snare comprising a snare wire having improved shearing force for ablation of a polyp and the like.SOLUTION: An endoscopic snare comprises a sheath, a cable slidably inserted in the sheath along the extending direction of the sheath, and a snare wire. One end and the other end in the extending direction of the snare wire are connected to one end in the extending direction of the cable to form a loop. The snare wire has a first side, a second side continuous with the first side, and a corner portion formed of the first side and the second side, in a cross-sectional view to be perpendicular to the extending direction of the snare wire. The corner portion is directed to the inside of the loop.SELECTED DRAWING: Figure 1

Description

The present invention relates to an endoscopic snare. More specifically, the present invention relates to an endoscopic snare that is inserted into the body through a forceps channel of an endoscope to capture and excise tissues such as polyps in the gastrointestinal tract.

In the excision of polyps and the like with an endoscopic snare inserted into the body through the forceps channel of the endoscope, the roots of the polyps and the like are squeezed by a snare wire formed in a loop shape, and a high-frequency current is passed through the snare wire. It is common to be done. However, this resection may require long-term observation after surgery because the burns at the resection site may extend to the submucosa, causing the blood vessels to rupture and lead to post-bleeding.

Therefore, for polyps and the like having a small size (for example, less than 10 mm), cold polypectomy may be selected in which the polyps and the like are excised only by strangulation of the roots of the polyps and the like without energization. .. Since cold polypectomy is a resection localized to the mucosa, although there is bleeding immediately after resection, the risk of post-bleeding is low, it is relatively safe, and it is recognized as a treatment method that cures quickly.

The snare wire in the endoscopic snare described in Patent Document 1 has a triangular shape or a quadrangular shape in a cross-sectional view, but the triangular shape or the side of the quadrangular shape is inside a loop formed by the snare wire. Suitable for. From another point of view, the cut surface of the snare wire in the endoscopic snare described in Patent Document 1 is formed of a flat surface.

Japanese Patent No. 4347584

In cold polypectomy, the polyp or the like is excised only by strangling the root of the polyp or the like with the snare wire, so that the snare wire is required to have a shearing force. However, since the cut surface of the snare wire in the endoscopic snare of Patent Document 1 is formed of a flat surface, there is room for improvement in the shearing force when cutting a polyp or the like.

The present invention has been made in view of the above-mentioned problems of the prior art. More specifically, the present invention provides an endoscopic snare having a snare wire having an improved shearing force when cutting a polyp or the like.

The endoscopic snare according to one aspect of the present invention includes a sheath, a cable slidably inserted into the sheath along the extending direction of the sheath, and a snare wire. One end and the other end of the snare wire in the extending direction are connected to one end in the extending direction of the cable so as to form a loop. The snare wire has a first side, a second side connected to the first side, and a corner formed by the first side and the second side in a cross-sectional view orthogonal to the extending direction of the snare wire. .. The corners face the inside of the loop.

In the above-mentioned endoscopic snare, the corners may be formed continuously along the extending direction of the snare wire over a part or all of the loop.

In the endoscopic snare described above, the loop may have a first portion and a second portion facing the first portion in the width direction of the loop. The corner portion may be formed in either the first portion or the second portion.

In the above-mentioned endoscopic snare, the angle formed by the first side and the second side may be 30 ° or more and 90 ° or less.

In the above-mentioned endoscopic snare, the snare wire may have a triangular shape in a cross-sectional view orthogonal to the extending direction of the snare wire. In the above-mentioned endoscopic snare, the length of one side of the triangular shape may be 0.1 mm or more and 0.4 mm or less.

In the endoscopic snare described above, the loop may have a protrusion located at the tip of the loop.

In the above-mentioned endoscopic snare, the shape of the loop may be any of a circular shape, an elliptical shape, a teardrop shape, a rhombus shape, and a hexagonal shape in the expanded state.

In the above-mentioned endoscopic snare, the corners may be chamfered. In the above-mentioned endoscopic snare, the snare wire may be a single wire. In the above-mentioned endoscopic snare, the snare wire may be a wire made of a superelastic alloy.

According to the endoscopic snare according to one aspect of the present invention, it is possible to improve the shearing force of the snare wire when excising a polyp or the like.

It is a top view of the snare 10 for an endoscope. It is sectional drawing of the snare wire 3 in the cross-sectional view orthogonal to the extending direction of the snare wire 3 in the snare 10 for an endoscope. It is a top view of the snare 10 for an endoscope in the state where the loop 31 is reduced in diameter. It is a top view of the snare wire 3 in the snare 10A for an endoscope. It is a top view of the snare wire 3 in the 1st modification of the snare 10A for an endoscope. It is a top view of the snare wire 3 in the 2nd modification of the snare 10A for an endoscope. It is a top view of the snare wire 3 in the 3rd modification of the snare 10A for an endoscope. It is sectional drawing of the snare wire 3 in the cross-sectional view orthogonal to the extending direction of the snare wire 3 in the snare 10B for an endoscope. It is sectional drawing of the snare wire 3 in the cross-sectional view orthogonal to the extending direction of the snare wire 3 in the 1st modification of the snare 10B for an endoscope. It is sectional drawing of the snare wire 3 in the cross-sectional view orthogonal to the extending direction of the snare wire 3 in the 2nd modification of the snare 10B for an endoscope. It is sectional drawing of the snare wire 3 in the cross-sectional view orthogonal to the extending direction of the snare wire 3 in the snare 10C for an endoscope. It is sectional drawing of the snare wire 3 in the cross-sectional view orthogonal to the extending direction of the snare wire 3 in the snare 10D for an endoscope.

The details of the embodiment will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate explanations will not be repeated.

(First Embodiment)
The endoscope snare (hereinafter referred to as “endoscopic snare 10”) according to the first embodiment will be described below.

<Structure of snare 10 for endoscope>
FIG. 1 is a plan view of the endoscope snare 10. As shown in FIG. 1, the endoscope snare 10 has a sheath 1, a cable 2, a snare wire 3, and a hand operation unit 4. The endoscopic snare 10 is used by being inserted into the body through a forceps channel (not shown) of the endoscope.

The sheath 1 is a tubular member. That is, the sheath 1 has a hollow inside. The sheath 1 has a first end 1a and a second end 1b. The first end 1a and the second end 1b are the ends of the sheath 1 in the extending direction of the sheath 1. The second end 1b is the opposite end of the first end 1a.

The sheath 1 is preferably made of a material having appropriate flexibility and rigidity, low surface friction resistance, and low stretchability. The sheath 1 is made of, for example, polypropylene, a fluororesin, or the like. The outer diameter and length of the sheath 1 are appropriately selected so that they can be inserted into the forceps channel.

The cable 2 is a wire-shaped member. The cable 2 has a first end 2a and a second end 2b (not shown). The first end 2a and the second end 2b are the ends of the cable 2 in the extending direction of the cable 2. The second end 2b is the opposite end of the first end 2a. The cable 2 is inserted into the sheath 1. The cable 2 is slidable in the sheath 1 along the extending direction of the sheath 1. The outer diameter of the cable 2 is smaller than the inner diameter of the sheath 1.

The cable 2 is preferably made of a material having appropriate flexibility and rigidity, low stretchability, and appropriate torque property. The cable 2 is formed of, for example, a metal stranded wire obtained by twisting a plurality of metal wires formed of stainless steel or the like.

The snare wire 3 is a wire-shaped member. The snare wire 3 has a first end 3a and a second end 3b. The first end 3a and the second end 3b are the ends of the snare wire 3 in the extending direction of the snare wire 3. The second end 3b is the opposite end of the first end 3a. The first end 3a and the second end 3b of the snare wire 3 are connected to the first end 2a of the cable 2. This connection is made, for example, by caulking through the pipe 21. The snare wire 3 is preferably electrically connected to the cable 2.

The snare wire 3 is preferably formed of a single wire. The snare wire 3 is preferably formed of a wire made of a superelastic alloy. The superelasticity refers to the property of returning to the original shape except for the external force even after applying an external force enough to cause plastic strain, and the superelastic alloy means an alloy having such a property. .. Examples of superelastic alloys include nickel (Ni) -titanium (Ti) alloys.

The snare wire 3 is connected to the cable 2 to form a loop 31. The loop 31 protrudes from the sheath 1 (first end 1a) in the expanded state. The loop 31 has a first portion 31a and a second portion 31b. The first portion 31a and the second portion 31b face each other in the first direction DR1 which is a direction along the width of the loop 31. The loop 31 further has a protrusion 31c. The protrusion 31c is located at the tip of the loop 31. The tip of the loop 31 is a portion of the loop 31 located at the position farthest from the first end 1a of the sheath 1 in the second direction DR2 orthogonal to the first direction DR1.

The loop 31 has, for example, a rhombus shape. Even if the corners of the loop 31 in the first direction DR1 are rounded, they are included in the "diamond shape" here. The snare wire 3 is stored in advance so that the loop 31 has a predetermined shape. Further, the loop 31 deviates from the rhombic shape at the portion where the protruding portion 31c is located. It is assumed that the loop 31 still has a "diamond shape" even if it has such a protruding portion 31c.

FIG. 2 is a cross-sectional view of the snare wire 3 in a cross-sectional view orthogonal to the extending direction of the snare wire 3 in the snare 10 for an endoscope. As shown in FIG. 2, in a cross-sectional view orthogonal to the extending direction of the snare wire 3, the snare wire 3 has a first side 32, a second side 33, and a corner portion 34. The second side 33 is continuous with the first side 32. The corner portion 34 is formed by connecting the second side 33 to the first side 32. Although not shown, the corners 34 are continuously formed over the entire loop 31 along the extending direction of the snare wire 3.

The corner portion 34 does not have to be continuously formed along the extending direction of the snare wire 3 over the entire loop 31. A plurality of portions of the snare wire 3 on which the corner portions 34 are formed may be arranged so as to be separated from each other along the extending direction of the snare wire 3.

In a cross-sectional view orthogonal to the extending direction of the snare wire 3, the snare wire 3 has, for example, a triangular shape. The length of one side of this triangular shape is preferably 0.1 mm or more and 0.4 mm or less.

The corners 34 face the inside of the loop 31. In addition, "the corner portion 34 faces the inside of the loop 31" means that the normal line of the plane defined by the loop 31 and the bisector of the angle formed by the first side 32 and the second side 33. It means that the angle formed by the bisector exceeds 45 °. The outer peripheral surface of the snare wire 3 facing the inside of the loop 31 becomes the cut surface when cutting a polyp or the like, but as a result of the corner portion 34 facing the inside of the loop 31, the corner portion 34 is a part of the cut surface. Will be configured. The angle formed by the first side 32 and the second side 33 is defined as the angle θ. The angle θ is preferably 30 ° or more and 90 ° or less. The angle θ is less than 180 °.

As shown in FIG. 1, the hand operation unit 4 has a sheath group 41 and a cable group 42. The sheath group 41 has a first end 41a and a second end 41b. The first end 41a and the second end 41b are the ends in the longitudinal direction of the sheath base 41. The second end 41b is the end opposite to the first end 41a.

The second end 1b of the sheath 1 is connected to the first end 41a of the sheath base 41. The sheath base 41 has a gripping ring 41c at the second end 41b. The grip ring 41c is a portion for the user of the endoscopic snare 10 to grip the sheath base 41. For example, the thumb of the user of the endoscopic snare 10 is inserted into the grip ring 41c.

The cable base 42 is connected to the second end 2b of the cable 2. The cable group 42 is configured to be slidable relative to the sheath group 41 along the longitudinal direction of the sheath group 41. The cable base 42 has a grip ring 42a and a grip ring 42b. The grip ring 42a and the grip ring 42b are portions for the user of the endoscopic snare 10 to grip the cable base 42. For example, the index finger and the middle finger (middle finger and ring finger) of the user of the endoscopic snare 10 are inserted into the grip ring 42a and the grip ring 42b, respectively.

The cable base 42 may have a terminal 42c. The terminal 42c is electrically connected to the cable 2. A high frequency current is supplied to the terminal 42c. This high frequency current is supplied to the snare wire 3 via the cable 2. That is, in the endoscopic snare 10, the polyp or the like may be squeezed by the snare wire 3 and the polyp or the like may be excised by supplying a high frequency current to the snare wire 3. From another point of view, the endoscopic snare 10 may be used in addition to the cold polypectomy.

<Operation of snare 10 for endoscope>
FIG. 3 is a plan view of the endoscope snare 10 in a state where the loop 31 is reduced in diameter. As shown in FIG. 3, the cable group 42 is slid relative to the sheath group 41 from the first end 41a side to the second end 41b side of the sheath group 41, so that the loop 31 is sheathed. It is pulled into 1 and the diameter is reduced. On the other hand, as the cable base 42 slides relative to the sheath base 41 from the second end 41b side toward the first end 41a side, the loop 31 protrudes from the sheath 1 and expands. It returns to the state shown in FIG.

The endoscope snare 10 is inserted in the vicinity of the target site by being passed through the forceps channel of the endoscope in a state where the loop 31 is reduced in diameter. After the endoscopic snare 10 is inserted in the vicinity of the target site, the loop 31 protrudes from the sheath 1 and is expanded by sliding the cable base 42 with respect to the sheath base 41. With the root of the polyp or the like positioned in the expanded loop 31, the cable base 42 is slid with respect to the sheath base 41 and the loop 31 is pulled into the sheath 1 to reduce the diameter of the polyp or the like. Captured and excised.

<Effect of snare 10 for endoscope>
The outer peripheral surface of the snare wire 3 facing the inside of the loop 31 is the cut surface when cutting a polyp or the like, but the snare wire 3 has a corner portion facing the inside of the loop 31 in a cross-sectional view orthogonal to the extending direction of the snare wire 3. Since 34 is formed, the corner portion 34 constitutes a part of the cut surface. Therefore, in the endoscopic snare 10, the shearing force of the snare wire 3 is improved.

In an endoscopic snare, it is necessary to reduce the diameter of the snare wire in order to improve the shearing force of the snare wire. However, when the diameter of the snare wire is reduced, the rigidity of the snare wire becomes low (the stiffness of the snare wire is lost), and it becomes difficult for the snare loop to catch polyps and the like. In the endoscopic snare 10, it is not necessary to make the snare wire 3 thin enough to eliminate stiffness in order to increase the shearing force of the snare wire 3, so that polyps and the like can be easily captured.

Further, according to the endoscopic snare 10, the shearing force of the snare wire 3 is improved, and as a result, the binding force required for excising the polyp or the like is reduced, so that the load on the residual tissue of the excised site can be reduced. It becomes.

If the angle θ is too large, the cut surface of the snare wire 3 becomes close to a flat surface, so that the shearing force of the snare wire 3 decreases. On the other hand, if the angle θ is too small, the shearing force of the snare wire 3 is increased, but the corner portion 34 is liable to be damaged and processing becomes difficult. Therefore, by setting the angle θ to 30 ° or more and 90 ° or less, it is possible to suppress breakage of the snare wire 3 while maintaining the shearing force and workability of the snare wire 3.

As the snare wire 3 becomes thinner, the shearing force of the snare wire 3 increases, but the rigidity of the snare wire 3 also decreases. Therefore, by setting the length of one side of the triangular cross-sectional shape of the snare wire 3 to 0.1 mm or more and 0.4 mm or less, it is possible to maintain the rigidity (stiffness) of the snare wire 3 while maintaining the shearing force of the snare wire 3. It will be possible. When the snare wire 3 is formed of a single wire, the rigidity of the snare wire 3 can be increased.

(Second Embodiment)
The endoscope snare (hereinafter referred to as “endoscopic snare 10A”) according to the second embodiment will be described below. Here, the differences from the endoscopic snare 10 will be mainly described, and the duplicated explanation will not be repeated.

<Structure of snare 10A for endoscope>
The endoscope snare 10A has a sheath 1, a cable 2, a snare wire 3, and a hand operation unit 4. In this respect, the configuration of the endoscope snare 10A is common to the configuration of the endoscope snare 10.

FIG. 4 is a plan view of the snare wire 3 in the endoscope snare 10A. As shown in FIG. 4, in the endoscopic snare 10A, the loop 31 has a circular shape. In this respect, the configuration of the endoscopic snare 10A is different from the configuration of the endoscopic snare 10.

<Modification example>
FIG. 5 is a plan view of the snare wire 3 in the first modification of the endoscope snare 10A. As shown in FIG. 5, the loop 31 may have an elliptical shape. FIG. 6 is a plan view of the snare wire 3 in the second modification of the endoscope snare 10A. As shown in FIG. 6, the loop 31 may have a hexagonal shape. This hexagonal shape is a rhombic shape of the loop 31 shown in FIG. 1 in which the corners in the first direction DR1 are straight. FIG. 7 is a plan view of the snare wire 3 in the third modification of the endoscope snare 10A. As shown in FIG. 7, the loop 31 may be in the shape of a teardrop. The shape of the loop 31 is not limited to these.

(Third Embodiment)
The endoscope snare (hereinafter referred to as “endoscopic snare 10B”) according to the third embodiment will be described below. Here, the differences from the endoscopic snare 10 will be mainly described, and the duplicated explanation will not be repeated.

<Structure of snare 10B for endoscope>
The endoscope snare 10B has a sheath 1, a cable 2, a snare wire 3, and a hand operation unit 4. In this respect, the configuration of the endoscope snare 10B is common to the configuration of the endoscope snare 10.

FIG. 8 is a cross-sectional view of the snare wire 3 in a cross-sectional view orthogonal to the extending direction of the snare wire 3 in the snare 10B for an endoscope. As shown in FIG. 8, in the endoscopic snare 10B, the snare wire 3 has a quadrangular shape in a cross-sectional view orthogonal to the extending direction of the snare wire 3. In this respect, the configuration of the endoscopic snare 10B is different from the configuration of the endoscopic snare 10.

<Modification example>
FIG. 9 is a cross-sectional view of the snare wire 3 in a cross-sectional view orthogonal to the extending direction of the snare wire 3 in the first modification of the endoscope snare 10B. As shown in FIG. 9, the snare wire 3 may have a pentagonal shape in a cross-sectional view orthogonal to the extending direction of the snare wire 3. This pentagonal shape is a shape in which a corner portion 34 projects from one side of the quadrangular shape toward the inside of the loop 31.

FIG. 10 is a cross-sectional view of the snare wire 3 in a cross-sectional view orthogonal to the extending direction of the snare wire 3 in the second modification of the endoscope snare 10B. As shown in FIG. 10, the snare wire 3 may have a fan shape in a cross-sectional view orthogonal to the extending direction of the snare wire 3. The cross-sectional shape of the snare wire 3 is not limited to these.

(Fourth Embodiment)
The endoscope snare (hereinafter referred to as “endoscopic snare 10C”) according to the fourth embodiment will be described below. Here, the differences from the endoscopic snare 10 will be mainly described, and the duplicated explanation will not be repeated.

The endoscope snare 10C has a sheath 1, a cable 2, a snare wire 3, and a hand operation unit 4. In this respect, the configuration of the endoscope snare 10C is common to the configuration of the endoscope snare 10.

FIG. 11 is a cross-sectional view of the snare wire 3 in a cross-sectional view orthogonal to the extending direction of the snare wire 3 in the snare 10C for an endoscope. As shown in FIG. 11, in the endoscopic snare 10C, the corner portion 34 may be chamfered. In this respect, the configuration of the endoscopic snare 10C is different from the configuration of the endoscopic snare 10.

(Fifth Embodiment)
The endoscope snare (hereinafter referred to as “endoscopic snare 10D”) according to the fifth embodiment will be described below. Here, the differences from the endoscopic snare 10 will be mainly described, and the duplicated explanation will not be repeated.

The endoscope snare 10D has a sheath 1, a cable 2, a snare wire 3, and a hand operation unit 4. In this respect, the configuration of the endoscope snare 10D is common to the configuration of the endoscope snare 10.

FIG. 12 is a cross-sectional view of the snare wire 3 in a cross-sectional view orthogonal to the extending direction of the snare wire 3 in the snare 10D for an endoscope. Note that FIG. 12A shows the cross-sectional shape of the snare wire 3 in the first portion 31a, and FIG. 12B shows the cross-sectional shape of the snare wire 3 in the second portion 31b.

As shown in FIG. 12, the cross-sectional shape of the snare wire 3 orthogonal to the extending direction has a corner portion 34 in the first portion 31a, while having a corner portion 34 in the second portion 31b. Not (eg, has a circular shape). That is, the corner portion 34 is continuously formed over a part of the loop 31 along the extending direction of the snare wire 3. In this respect, the configuration of the endoscopic snare 10D is different from the configuration of the endoscopic snare 10.

Although the embodiment of the present invention has been described above, it is possible to modify the above-described embodiment in various ways. Moreover, the scope of the present invention is not limited to the above-described embodiment. The scope of the present invention is indicated by the scope of claims and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

This embodiment is particularly advantageously applied to endoscopic snares used in cold polypectomy.

1 sheath, 1a 1st end, 1b 2nd end, 2 cables, 2a 1st end, 2b 2nd end, 21 pipes, 3 snare wires, 3a 1st end, 3b 2nd end, 31 loops, 31a 1st part, 31b 2nd part, 31c protruding part, 32 1st side, 33 2nd side, 34 corner part, 4 hand operation part, 41 sheath group, 41a 1st end, 41b 2nd end, 41c grip ring, 42 cable group, 42a, 42b grip ring, 42c terminal, DR1 first direction, DR2 second direction, 10,10A, 10B, 10C, 10D endoscope snare.

Claims (11)

With the sheath
A cable inserted into the sheath so as to be slidable along the extending direction of the sheath,
Equipped with a snare wire,
One end and the other end of the snare wire in the extending direction are connected to one end of the cable in the extending direction so as to form a loop.
The snare wire includes a first side, a second side connected to the first side, and a corner formed by the first side and the second side in a cross-sectional view orthogonal to the extending direction of the snare wire. Have and
An endoscopic snare whose corners face the inside of the loop. The endoscopic snare according to claim 1, wherein the corner portion is continuously formed along a extending direction of the snare wire over a part or all of the loop. The loop has a first portion and a second portion facing the first portion in the width direction of the loop.
The endoscope snare according to claim 1 or 2, wherein the corner portion is formed in either the first portion or the second portion. The endoscope snare according to any one of claims 1 to 3, wherein the angle formed by the first side and the second side is 30 ° or more and 90 ° or less. The endoscope snare according to any one of claims 1 to 4, wherein the snare wire has a triangular shape in a cross-sectional view orthogonal to the extending direction of the snare wire. The endoscope snare according to claim 5, wherein the length of one side of the triangular shape is 0.1 mm or more and 0.4 mm or less. The endoscope snare according to any one of claims 1 to 6, wherein the loop has a protrusion located at the tip of the loop. The endoscope shape according to any one of claims 1 to 7, wherein the shape of the loop is any of a circular shape, an elliptical shape, a teardrop shape, a rhombus shape, and a hexagonal shape in the expanded state. Snare. The endoscope snare according to any one of claims 1 to 8, wherein the corner portion is chamfered. The endoscope snare according to any one of claims 1 to 9, wherein the snare wire is a single wire. The endoscope snare according to any one of claims 1 to 10, wherein the snare wire is a wire made of a superelastic alloy.

Images