JP4394401B2 - Endoscope snare - Google Patents

Description

  The present invention relates to an endoscopic snare used to cut a polyp through a treatment instrument insertion channel of an endoscope.

  In general, a snare for an endoscope has an operation wire inserted through a flexible sheath so as to be movable back and forth in the axial direction, and a snare loop made of a stranded wire is connected to the tip of the operation wire. The snare loop moves in and out of the distal end of the flexible sheath by moving forward and backward, and the snare loop swells by its own elasticity outside the flexible sheath and elastically deforms by being pulled into the flexible sheath. It is getting squeezed.

In such an endoscopic snare, the snare loop is formed by bending one strand wire back at the tip to form a loop, or two strand wires arranged in parallel at both front and rear ends. In other words, the middle portion is bent in a loop shape (Patent Document 1).
JP 2000-83963, FIG. 4 and FIG.

  However, if a single wire is bent back at the tip to form a snare loop, the twisted wire is likely to be loosened at the bent back portion of the tip, and as a result, the shape collapses after one use and is durable. It can be very short.

  In addition, when two strand wires are arranged in parallel at the front and rear ends and joined to each other and the middle portion is bent into a loop shape, the two strand wires are arranged in parallel. Due to the shape, when the snare loop is drawn into the flexible sheath and narrowed, for example, the snare loop does not spread as it is and the performance tends to deteriorate.

  Therefore, an object of the present invention is to provide an endoscope snare that is excellent in durability and has a snare loop that spreads stably in a large loop shape.

  In order to achieve the above object, an endoscope snare according to the present invention has a snare composed of a stranded wire at the tip of the operation wire, in which an operation wire is inserted and disposed in a flexible sheath so as to be movable back and forth in the axial direction. The loop is connected, and the snare loop moves in and out of the distal end of the flexible sheath by operating the operation wire forward and backward in the axial direction, and the snare loop expands by its own elasticity outside the flexible sheath, and the flexible sheath In an endoscopic snare that is elastically deformed and narrowed by being pulled in, a snare loop is formed by two stranded wires joined to each other at both front and rear ends, and a joint portion on the tip side thereof In which two stranded wires are joined at an acute angle, and the crossing angle of the two stranded wires at the joint on the tip side of the snare loop is 10 °. If above it is possible to obtain a sufficient effect.

  In addition, it is excellent in strength and the expansion / contraction shape of the snare loop when the strands constituting each stranded wire are engaged with each other at the joint portion on the distal end side of the two stranded wires. In order to construct, after the strand wires are once loosened and the strands constituting the strand wires are engaged with each other at the joint portion on the tip side of the two strand wires, the strands are twisted. It may be returned and joined.

  In addition, when at least one of the two stranded wires has a core wire at the axial position, if the core wire is cut off at a portion ahead of the vicinity of the joint portion on the distal end side, the relationship between the two stranded wire wires can be reduced. Easy to join.

  According to the present invention, a snare loop is formed by two stranded wires joined to each other at both front and rear ends, and the two stranded wires are joined at an acute angle at the joint portion on the tip side. As a result, it is possible to obtain excellent durability by shortening the joint length without fraying the strands of the stranded wire, and even if the snare loop is once constricted, it becomes stable again in a large loop shape. Can be spread.

  A snare loop is formed by two stranded wires joined to each other at the front and rear ends, and the strands constituting each stranded wire are engaged with each other at the joint portion on the tip side of the two stranded wires. Then, the two stranded wires are joined so as to intersect at an acute angle.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a distal end portion of an endoscope snare, for example, a stainless steel stranded wire in a flexible sheath 1 made of an electrically insulating flexible tube such as a tetrafluoroethylene resin tube. A highly conductive flexible operation wire 2 such as the above is inserted and arranged so as to freely advance and retract in the axial direction.

  Two stranded wires 4 and 5 forming a snare loop 10 are connected to the distal end of the operation wire 2 via a metal connection pipe 3 and connected to the proximal end of the flexible sheath 1. When the operation wire 2 is moved back and forth in an operating portion (not shown), the snare loop 10 enters and exits from the distal end of the flexible sheath 1, and the snare loop 10 is self-elastic outside the flexible sheath 1. And is elastically deformed and squeezed by being drawn into the flexible sheath 1. The snare loop 10 can be energized with a high-frequency current from the operation unit side via the operation wire 2.

  The two stranded wires 4 and 5 constituting the snare loop 10 are each formed by twisting, for example, three stainless steel wires, and the rear end portions of the two stranded wires 4 and 5 Are arranged in parallel in the connection pipe 3, but the tip portions are arranged in a state of intersecting at an acute angle, and are joined to each other by, for example, silver brazing, gold brazing, laser spot welding or the like.

  Reference numeral 6 denotes the cross-joint portion, and the two stranded wires 4 and 5 can be joined with a short joint length without fraying the strands at the cross-joint portion 6, thereby obtaining excellent durability. be able to.

  Moreover, since the state where the two stranded wires 4 and 5 intersect at an acute angle at the tip is the natural shape of the snare loop 10, the snare loop 10 can be obtained even after the stranded wires 4 and 5 are elastically deformed and constricted. When in a free state in which no external force is applied, the shape returns to a sufficiently large shape.

  And if the crossing angle (theta) of the two strand wires 4 and 5 in the cross-junction part 6 is 10 degrees or more, such an effect is fully acquired, and an effect becomes so large that the crossing angle (theta) is large. However, if the crossing angle θ is 90 ° or more, defects such as being easily damaged at the time of constriction increase, so θ is an acute angle, and it is considered that the constriction method when the snare loop 10 is constricted is not insufficient. Then, the angle of θ may be selected. Practically, θ is preferably set in a range of about 30 ° to 60 °.

  Such a cross-junction 6 may be obtained by simply crossing and joining the two stranded wires 4 and 5, but as shown in FIG. The strand wires 4 and 5 are loosened once, and the strands constituting the strand wires 4 and 5 are engaged with each other, and then the strand wires 4 and 5 are returned to the original state as shown in FIG. After twisting back, the two stranded wires 4 and 5 may be joined at the cross-joining portion 6.

  In this way, when the strands constituting the stranded wires 4 and 5 are engaged with each other at the cross-joint portion 6, the coupling strength of the two stranded wires 4 and 5 is significantly improved. At the same time, for example, as shown in FIG. 4 illustrating the IV-IV cross section in FIG. 3, the two stranded wires 4, 5 are combined at the cross-joining portion 6 to form an equal cross-sectional shape, and the snare loop 10 This has a positive effect on the stability of the expansion / contraction shape.

  In addition, this invention is not limited to the said Example, For example, when at least one of the strand wire 4 and 5 has a core wire in an axial position like 7 strands, a core wire is ahead of the cross junction part 6. FIG. If it cuts off in the part of the side, engagement of the two strand wires 4 and 5 will be easy.

It is front sectional drawing of the front-end | tip part of the snare for endoscopes of the Example of this invention. It is a front view which shows the state of the engagement process in the cross-joining part of the two strand wire of the snare loop of the snare for endoscopes of the Example of the present invention. It is a front view of the cross joint part of the two strand wire of the snare loop of the snare for endoscopes of the example of the present invention. It is IV-IV sectional drawing in FIG. 3 of the snare for endoscopes of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible sheath 2 Operation wire 4,5 Stranded wire 6 Cross junction 10 Snare loop

Claims (3)

An operation wire is inserted and arranged in the flexible sheath so as to be movable back and forth in the axial direction, a snare loop made of a stranded wire is connected to the tip of the operation wire, and the operation wire is advanced and retracted in the axial direction. The snare loop enters and exits into the distal end of the flexible sheath, and the snare loop swells by its own elasticity outside the flexible sheath and is elastically deformed and constricted by being drawn into the flexible sheath. the endoscopic snare which is adapted,
What the snare loop, formed by two strands wires connected together at both front and rear ends, at the junction of the distal end side of the two twisted wire wire is bonded in a state of intersecting at an acute angle In
At the joint portion on the tip side of the two stranded wires, the stranded wires are once loosened and the strands constituting each stranded wire are brought into a state of being engaged with each other, and then twisted back and joined. Endoscopic snare characterized by being made .   The endoscope snare according to claim 1, wherein an angle of intersection of the two stranded wires at a joint portion on a distal end side of the snare loop is 10 ° or more. When at least one of the twisted wires of the two has a core in the axial position, of the front end side of the joint portion of the base front-side portions claim 1 or 2, wherein is excised from the end of the core wire Endoscope snare.

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