JP7728653B2 - Endoscopic treatment tools - Google Patents

Description

The present invention relates to a basket-type endoscopic treatment tool that is inserted into a body cavity through an endoscope channel and is used to grasp and remove foreign bodies such as stones from within the body cavity.

A basket-type endoscopic treatment tool has a basket section consisting of multiple elastic wires, each of which has a rear tip and a distal tip, connected to the distal end of a control wire inserted into a flexible sheath. When the control wire is advanced, the multiple elastic wires protruding from the flexible sheath bend outward, widening the spacing between them. When the control wire is retracted, the multiple elastic wires in this state close together and are housed within the distal end of the flexible sheath.

A basket-type endoscopic treatment instrument is inserted into an endoscope channel, and the endoscope is inserted into a body cavity such as a bile duct under fluoroscopic guidance. When the opening at the tip of the endoscope faces the body cavity containing a foreign object, such as a stone, to be removed, the guidewire inside the endoscope is manipulated to advance through the opening at the tip into the body cavity where the foreign object is located. The flexible sheath then engages and guides with the guidewire, entering the body cavity where the foreign object is located. Once the guidewire has passed the location of the foreign object, the basket portion, which advances distally from the flexible sheath when the operating wire is advanced, spreads the multiple elastic wires. The operating wire is then retracted to capture the foreign object, and, if necessary, to crush it using constriction pressure.

A basket-type endoscopic treatment instrument comprises a flexible sheath, a control wire inserted into the flexible sheath so as to be freely movable back and forth, and a basket section attached to the tip of the control wire, which bundles the proximal and distal ends of multiple elastic wires. When the basket section protrudes beyond the tip of the flexible sheath, the elastic wires elastically expand to form an intake space.

The basket portion expands within the body cavity and captures the stone by moving it within the cavity while maintaining its expanded state. Retracting the control wire narrows the capture space, capturing the stone.

Conventionally, basket sections have been proposed that are shaped so that the elastic wires cross the direction of movement when moved within the body cavity, preventing stones from slipping past the elastic wires, allowing foreign objects to come into contact with the elastic wires and capture the stones within the space (see, for example, Patent Documents 1 and 2).

Japanese Patent Application Publication No. 11-285500 Japanese Patent Application Laid-Open No. 2004-188011

The basket portion of the basket-type grasping forceps disclosed in Patent Document 1 has a diamond-shaped tip portion of each of multiple elastic wires to make it easier to capture stones. However, forming diamond-shaped portions is extremely difficult from a manufacturing perspective.

The basket portion of the basket-type grasping forceps disclosed in Patent Document 2 has a bent distal end portion of each of the four wires to form a capture space, which allows foreign objects to encounter the elastic wires and capture the foreign objects into the capture space. However, this basket portion has large wire spacing at the distal end, which allows stones to slip past the elastic wires when the capture space is narrowed. Specifically, the basket portion shown in Figures 1 and 5 of Patent Document 4 has a large gap between the bent portions of the two line segments W1 and W2 of one elastic wire and the line segment W1 adjacent to the one elastic wire. This gap does not narrow as the bent portion of P2 approaches the distal end of the flexible sheath as the basket portion narrows, so even if a foreign object is captured in the capture space, it will escape through this gap. Similarly, in the basket sections shown in Figures 3 and 4 of Patent Document 4, there is a large gap between the bent portions of the two line segments W1, W2, and W3 of one elastic wire and the line segment W1 adjacent to that elastic wire; this gap does not narrow as the basket section narrows because the bent portion of P2 approaches the tip of the flexible sheath, so even if a foreign object is taken into the space, it will escape through this gap.

In addition, stones, which are foreign bodies, come in a variety of sizes, and it is difficult to adjust the size of the capture space to match the size of the stone using the basket-type grasping forceps described above.

The present invention was devised to solve the above-mentioned problems, and aims to provide a basket-type endoscopic treatment instrument that is inserted into a body cavity via an endoscope and used to grasp and remove foreign bodies such as stones from within the body cavity, has an easily processable wire shape, makes it easy to capture and seize foreign bodies in the capture space, and can gradually narrow the capture space.

In order to solve the above-mentioned problems, the basket-type endoscopic treatment instrument of the present invention comprises a flexible sheath, a control wire inserted into the flexible sheath so as to be able to move back and forth freely, and a basket portion consisting of 3-8 elastic wires attached to the tip of the control wire, and a base-end binding tip and a tip-end binding tip that bind the base end and tip of the elastic wires together.

The basket portion is formed so that when the base end binding tip is positioned at the tip of the flexible sheath, the 3-8 elastic wires elastically expand to surround an oval or spherical intake space at equal intervals .

In particular, the basket-type endoscopic treatment instrument according to the present invention is
Each of the 3 to 8 elastic wires circumscribes the intake space and is divided into first to fourth line segments by a first bent portion, a second bent portion, and a third bent portion in this order from the base end side,
The first line segment of each of the elastic wires is
the first bent portions are arranged at positions that are approximately equally spaced around a sheath extension line that connects the proximal binding tip and the distal binding tip and on an ellipsoidal surface that corresponds to the middle of the sheath extension line,
a center of curvature radius from the base end binding tip to the middle of the line segment is on the outside, and a center of curvature radius from the middle of the line segment to the first bent portion is on the inside, and the shape circumscribes the intake space;
The fourth line segment of each of the elastic wires is
The center of the radius of curvature from the distal binding tip to the third bent portion is on the outside and has a shape that circumscribes the intake space,
The second line segment to the fourth line segment of each of the elastic wires are
The nozzle is characterized in that it is disposed in correspondence with the tip half of the oval or spherical intake space.

The present invention provides a basket-type endoscopic treatment instrument that can be inserted into a body cavity via an endoscope and used to grasp and remove foreign bodies such as stones from within the body cavity. The wire shape is easy to process, making it easy to capture and trap foreign bodies in the capture space, and the capture space can be gradually narrowed to match the size of the stone.

1 is a schematic view illustrating the principle of a basket-type endoscopic treatment tool according to a first embodiment of the present invention. 1A is a perspective view of a basket portion of a basket-type endoscopic treatment tool according to a first embodiment of the present invention, as viewed from the outside of the distal end, and FIG. 1B is a perspective view from the side. 1A is a front view of a basket portion of a basket-type endoscopic treatment tool according to a first embodiment of the present invention, FIG. 1B is a view taken along the arrows IIIB-IIIB in FIG. 1A, and FIG. 1C is a view taken along the arrows IIIC-IIIC in FIG. 1A. 1A is a front view of one elastic wire constituting a basket portion of a basket-type endoscopic treatment tool according to a first embodiment of the present invention, and FIG. 1B is a view taken along the arrows IVB-IVB in FIG. 1A. 1 is a side view of one elastic wire that constitutes a basket portion of a basket-type endoscopic treatment tool according to a first embodiment of the present invention. FIG. 1A-1C are diagrams showing the change in shape of a single elastic wire constituting the basket portion of a basket-type endoscopic treatment instrument according to embodiment 1 of the present invention, as the operating wire of the basket portion is advanced and retreated, and the change in the narrowing of the intake space. 1A and 1B show diagrams illustrating the change in capturing a small foreign body with the basket portion of the basket-type endoscopic treatment instrument according to the first embodiment of the present invention, in which (A) shows the foreign body being taken into the basket portion, (B) shows the foreign body being taken into the basket portion which has been narrowed by about one stage by moving the operating wire back and forth, and (C) shows the foreign body being taken into the basket portion which has been narrowed by about two stages by moving the operating wire back and forth. 1A and 1B show diagrams illustrating the change in capturing a large foreign body with the basket portion of the basket-type endoscopic treatment instrument according to the first embodiment of the present invention, in which (A) shows the foreign body being taken into the basket portion, (B) shows the foreign body being taken into the basket portion which has been narrowed by about one stage by moving the operating wire back and forth, and (C) shows the foreign body being taken into the basket portion which has been narrowed by about two stages by moving the operating wire back and forth. 10A and 10B are views of the basket portion of a basket-type endoscopic treatment instrument according to another embodiment of the present invention, viewed from the outside of the distal end, in which (A) shows a basket portion made of three elastic wires, (B) shows a basket portion made of four elastic wires, (C) shows a basket portion made of five elastic wires, (D) shows a basket portion made of six elastic wires, (E) shows a basket portion made of seven elastic wires, and (F) shows a basket portion made of eight elastic wires.

The following describes a basket-type endoscopic treatment tool according to an embodiment of the present invention, with reference to the drawings.

[Embodiment 1]
[Basic configuration]
The basket-type endoscopic treatment tool 100 shown in FIG. 1 comprises a flexible sheath 1, a control wire 2 inserted into the flexible sheath 1 so as to be able to move back and forth freely, a control section 3 connected to the base end of the flexible sheath 1 and holding the base end of the control wire 2 to control the control wire 2 to move back and forth, and a basket section 10 extended from the tip of the control wire 2 and capable of changing between a state housed within the tip end of the flexible sheath 1 and a state in which it protrudes forward of the flexible sheath 1 and expands into the three-dimensional shape shown in FIG. 2.

The flexible sheath 1 is formed from a coil, resin, or other material and has a long, flexible cylindrical shape that allows it to be inserted into the endoscope channel.

The operating wire 2 is inserted into the flexible sheath so that it can move back and forth freely. The operating wire 2 is made of a twisted wire separate from the elastic wire that makes up the basket section 10. The tip of the operating wire 2 is inserted into the proximal binding tip 14 and connected by soldering, brazing, laser welding, etc.

The operating unit 3 includes an operating unit main body 4, which is a molded body made of, for example, polycarbonate, and a grip portion 5 having an operating pipe 5a.

The operating unit main body 4 has a drug solution delivery path 6 to which a flexible sheath 1 is connected, and a drug inlet 7 to which a syringe or the like can be connected is provided at the rear end of the drug solution delivery path 6.

The gripping portion 5 has an operating pipe 5a that passes through the base end of the operating unit main body 4 and extends into the drug solution delivery path 6, housing and securing the base end of the operating wire 2.

The basket section 10 consists of five twisted elastic wires 11a-11e, a base-end binding tip 14 that binds the base ends of the elastic wires 11a-11e, and a tip-end binding tip 15 that binds the tip ends of the elastic wires 11a-11e. The base ends of the elastic wires 11a-11e are inserted into the base-end binding tip 14 and connected by soldering, brazing, laser welding, etc. The tips of the elastic wires 11a-11e are inserted into the tip-end binding tip 15 and connected by soldering, brazing, laser welding, etc.

By moving the gripper 5 back and forth, the operating wire 2 can be moved longitudinally within the flexible sheath 1. Furthermore, a syringe or similar device (not shown) can be attached to the drug inlet 7 to deliver drug solution into the flexible sheath 1.

[Characteristic Configuration]
The characteristic configuration of the basket-type endoscopic treatment tool 100 is the three-dimensional shape of the elastic wires 11a-11e in the basket section 10, which is made up of five elastic wires 11a-11e whose proximal and distal ends are bound together by a proximal binding tip 14 and a distal binding tip 15, as shown in Figures 2 and 3.

As shown in Figure 3, when the five elastic wires 11a-11e are protruded from the flexible sheath 1 from its interior, they elastically expand and circumscribe the intake space K at equal intervals. The intake space K is preferably ellipsoidal in shape.

For the basket section 10, it is desirable that the distance H1 from the proximal intersection of the intake space K and the sheath extension line Y to the proximal binding tip 14, and the distance H2 from the distal intersection of the intake space K and the sheath extension line Y to the distal binding tip 15, each be an appropriate value within the range of 2-6 mm. There is no particular problem if either distance H1 or distance H2 is longer.

Each first line segment 12a flares out from the proximal binding tip 14, and each fourth line segment 12d flares out from the distal binding tip 15.

Each of the five elastic wires 11a-11e is formed in a bifurcated serpentine shape, divided into first through fourth line segments 12a-12d by bent portions 13a-13c, starting from the base end.

The first line segment 12a flares out from the proximal binding tip 14, and the bent portion 13a (the tip of the first line segment 12a) with the second line segment 12b is arranged at approximately equal intervals around the sheath extension line Y connecting the proximal binding tip 14 and the distal binding tip 15, on an ellipsoidal surface corresponding to the middle of the sheath extension line Y.

As shown in Figure 4(B), the first through fourth line segments 12b-12d of each of the five elastic wires 11a-11e are formed into a two-peaked serpentine shape that bends in the same direction around the sheath extension line Y when the intake space K is viewed from the distal end binding tip 15 side (bent in the circumferential direction).

The peak formed by the first line segment 12a and the second line segment 12b of each elastic wire 11a-11e may be higher than the peak formed by the third line segment 12c and the fourth line segment 12d, or may be formed at approximately the same height. The valley angle of the peak formed by the first line segment and the second line segment, the valley angle of the valley formed by the second line segment and the third line segment, and the valley angle of the peak formed by the third line segment and the fourth line segment may each be set to an appropriate angle, but it is preferable that the valley angles are 90 degrees plus or minus 30 degrees.

Figure 5 is a side view of a single elastic wire that constitutes the basket portion of a basket-type endoscopic treatment tool according to embodiment 1 of the present invention, and is a diagram illustrating the degree of bending of the first line segment extending from the proximal bundling tip and the fifth line segment extending from the distal bundling tip.

The first line segment 12a flares out from the base-end binding tip 14, and the fourth line segment 12d flares out from the tip-end binding tip 15. The first line segment 12a has a shape in which the center of curvature of the radius of curvature is on the outside from the base-end binding tip 14 to halfway along the line segment (curved convexly toward the intake space K), and a center of curvature of the radius of curvature is on the inside from halfway along the line segment to the first bend 13a (curved convexly toward the outside of the intake space K), tangentially circumscribing the intake space K at the first bend 13a. Similarly, the fourth line segment 12d flares out from the tip-end binding tip 15 over its entire length or at least halfway along the line segment so that the center of curvature of the radius of curvature R3 is on the outside , and is positioned so as to tangentially circumscribing the intake space K when it reaches the third bend 13c.

The flared shape of the first line segment 12a, the flared shape of the fourth line segment 12d, and the two-ridge shape formed by the first, second, and fourth line segments 12a-12d work in concert to reverse the shape of the ridges and valleys as the basket section 10 narrows when the proximal binding tip 14 moves proximally within the flexible sheath 1. This prevents the capture space K from suddenly disappearing into a flat shape, and allows the capture space K to narrow through large, medium, and small stages, allowing for smooth capture of foreign objects.

In other words, as shown in FIG. 5, the first line segment 12a and the fourth line segment 12d flare out on the same side of the line connecting the base end binding tip 14 and the tip end binding tip 15, and the first line segment 12a and the fourth line segment 12d are not connected by a smooth arc segment, but by the second line segment 12b and the third line segment 12d. Therefore, when the basket section 10 narrows, the intake space K does not suddenly disappear into a flat shape. Instead, the basket section 10 has the function of narrowing through large, medium, and small stages of a large-sized intake space made up of the first line segment 12a to the fourth line segment 12d (FIG. 6(A)), a medium-sized intake space made up of the second line segment 12b to the fourth line segment 12d (FIG. 6(B)), and a small-sized intake space made up of the third line segment 12c to the fourth line segment 12d (FIG. 6(C)). Therefore, the size of the intake space can be selected according to the size of the stone. Furthermore, because the second to fourth line segments 12b-12d are arranged to correspond to the leading edge half of the intake space K, a gap is secured between adjacent first line segments 12a that makes it easy for foreign matter to be drawn into the intake space K, and the gap between adjacent second to fourth line segments 12b-12d has the function of capturing foreign matter that has entered the intake space K.

Figures 6(A)-(C) show the change in shape of one of the five elastic wires 11a that make up the basket section when the operating wire 2 moves proximally within the flexible sheath 1, causing the five elastic wires to be pulled into the flexible sheath 1. They also show the size of the capture spaces K1-K3, which narrow in stages from large to small, as the operating wire 2 moves proximally within the flexible sheath 1. They also show the state in which a small foreign body S is captured within the capture space S.

In this way, by making the first and fifth line segments shown in Figure 3 curved as shown in Figure 5, when the five elastic wires 11a-11e are pulled into the flexible sheath 1, the elastic wires of the five elastic wires 11a-11e that are positioned opposite each other on either side of the capture space K reverse their curved state and overlap. As a result, the capture space K does not disappear all the way around, preventing it from being able to capture the foreign body S. Instead, the capture space S can be steadily narrowed in size in stages as shown in Figures 6(A)-(C).

Figures 7(A)-(C) are diagrams showing the change in shape of the five elastic wires that make up the prototype basket section 10 as they are retracted into the flexible sheath 1, and also the state in which a small foreign body S is captured within the capture space. Figure 7(A) shows the capture of a foreign body S into the basket section 10, (B) shows the capture of a foreign body S into the basket section 10 that has narrowed by approximately one stage as the operating wires are advanced and retracted, and (C) shows the capture of a foreign body into the basket section that has narrowed by approximately two stages as the operating wires are advanced and retracted.

Figures 8(A)-(C) are diagrams showing the change in shape of the five elastic wires that make up the prototype basket section 10 as they are retracted into the flexible sheath 1, and also showing the state in which the largest possible foreign object S is captured into the capture space. Figure 8(A) shows the foreign object being captured into the basket section, (B) shows the foreign object being captured into the basket section that has narrowed by about one stage as the operating wire is advanced and retracted, and (C) shows the foreign object being captured into the basket section that has narrowed by about two stages as the operating wire is advanced and retracted.

An example of a specific size of the basket section 10 will be described.
3A, 4A, and 4B, the elastic wires 11a-11e are bent to form first to third bent portions 13a-13c and first to fourth line segments 12a-12d. Assuming the total length of the elastic wire is 72 mm, the lengths of the portions bound by the proximal binding tip 14 and distal binding tip 15 are approximately 6 mm, the fourth line segment 12d is 15 mm, the second and third line segments 12b and 12c are each 10 mm, and the remaining length (approximately 25 mm) is the first line segment 12a. The bent portions 13a between the first line segment 12a and the second line segment 12b of each of the five elastic wires 11a-11e are equally spaced circumferentially around the intake space K with a spacing of approximately 3.5 mm. The bent portions may be formed using shape memory.

Next, we will explain how to retrieve a foreign body S (e.g., a bile duct stone) using the basket-type endoscopic treatment tool 100 configured as described above.

First, with the basket portion 10 of the basket-type endoscopic treatment tool 100 shown in Figure 1 housed within the flexible sheath 1, the basket portion 10 is introduced into a body cavity, for example, through a channel (not shown) of an endoscope equipped with a side-viewing forceps elevator. Then, the distal end of the flexible sheath 1 is protruded from the distal end of the endoscope and inserted into the bile duct via the duodenal papilla.

Next, the gripping portion 5 at the base end of the flexible sheath 1 is operated to advance the operating wire 2, causing the basket portion 10 to protrude from the tip of the flexible sheath 1. As a result, the basket portion 10 expands as shown in Figures 2(A) and 2(B) due to the elastic restoring forces of the five elastic wires 11a-11e.

Next, as shown in Figures 7(A) and 8(A), the stone S is captured within the expanded basket unit 10. Next, the operating means at the proximal end of the flexible sheath 1 is operated to retract the operating wire 2, and as shown in Figures 7(B) and 8(B), the basket unit 10 is contracted while being housed within the flexible sheath 1. At this time, the five elastic wires 11a-11e of the basket unit 10 are expanded three-dimensionally, significantly increasing the opportunity for them to come into contact with the stone. Therefore, even when the basket unit 10 is contracted, there is almost no risk of the stone escaping through the gaps between the deformed wires. Instead, the stone within the basket unit 10 is securely in contact with the wires, ensuring that the stone is securely held within the basket unit 10. The basket unit is then removed from the body cavity together with the endoscope, allowing the stone S to be retrieved.

In this way, the basket portion 10 is made of five twisted elastic wires 11a-11e, and the first line segment 12a of the five elastic wires 11a-11e is curved outward near the base end binding tip 14, and the fourth line segment 12d is curved outward near the tip end binding tip 15. As a result, the basket portion 10 made of the five elastic wires 11a-11e forms an oval spherical capture space K. When the basket portion 10 is pulled into the flexible sheath 1 to capture a stone, the force tends to escape to the side, causing the basket portion 10 to rotate, and the capture space K is not likely to collapse all at once, and the shape is maintained stably, making it easy to capture stones. Furthermore, when the basket section 10 is pulled into the flexible sheath 1, the rotation of the basket section 10 occurs in a right-left-right rotation pattern due to the two-ridge serpentine shape of each of the five elastic wires 11a-11e, narrowing the capture space K and eliminating the risk of stones captured within the basket section 10 falling out of the basket section 10.

[Other embodiments]
[Number of elastic wires in the basket]
The basket section is not limited to one made up of five elastic wires, and may be one made up of three to eight elastic wires, as shown in Figure 9. Figures 9(A) to 9(F) are views of the basket section viewed from the outside of the tip, with (A) showing a basket section made up of three elastic wires, (B) showing a basket section made up of four elastic wires, (C) showing a basket section made up of five elastic wires, (D) showing a basket section made up of six elastic wires, (E) showing a basket section made up of seven elastic wires, and (F) showing a basket section made up of eight elastic wires.

As shown in Figures 9(A)-(F), the fewer the number of elastic wires, the greater the height of the two peaks in the basket section and the deeper the valleys, which will provide a better capture function. However, since the resistance increases when pulling the wire into the flexible sheath, it is advisable to increase the power factor radius of the bending section.

[About the space in the basket that captures foreign objects]
The space for capturing foreign objects surrounded by the multiple elastic wires of the basket section is not limited to the ellipsoidal shape shown in the first embodiment, but may also be spherical. The space for capturing foreign objects is an invisible virtual space. If the first line segments of the multiple elastic wires flare out and the second line segments through the fourth line segments are evenly arranged radially in the circumferential direction so as to occupy half of the ellipsoidal or spherical surface, it can be said that the multiple elastic wires substantially surround the ellipsoidal or spherical space for capturing foreign objects.

According to the embodiment described above, the wire shape is easy to process, and when it protrudes from the distal end of the flexible sheath and elastically expands, it forms an ingesting space. The operating wire spacing is larger in the proximal half of this ingesting space and smaller in the distal half, making it easier to ingest and capture foreign bodies in the proximal half and the distal half. As the basket portion is retracted into the flexible sheath, the ingesting space can be gradually narrowed, resulting in fewer foreign bodies being missed, from small to large. This provides an excellent basket-type endoscopic treatment instrument that can be inserted endoscopically into a body cavity to grasp and remove foreign bodies such as stones from within the body cavity.

DESCRIPTION OF SYMBOLS 1... Flexible sheath 2... Operation wire 3... Operation section 4... Operation section main body 5... Grip section 5a... Operation pipe 6... Drug solution delivery path 7... Medication inlet 10... Basket section 11a-11d... Elastic wire 12a-12d... First to fourth line segments 13a-13c... Bending section 14... Proximal binding tip 15... Distal binding tip K, K1-K4... Capture space Y... Sheath extension line S... Foreign matter

Claims (1)

A basket-type endoscopic treatment instrument comprising: a flexible sheath; an operating wire inserted into the flexible sheath so as to be freely movable back and forth; and a basket portion consisting of 3-8 elastic wires provided at the distal end of the operating wire, and a proximal end bundling tip and a distal end bundling tip bundling the proximal end and distal end of the elastic wires, wherein the basket portion is formed such that when the proximal end bundling tip is located at the distal end of the flexible sheath, the 3-8 elastic wires elastically expand to surround an oval or spherical intake space at equal intervals,
Each of the 3 to 8 elastic wires circumscribes the intake space and is divided into first to fourth line segments by a first bent portion, a second bent portion, and a third bent portion in this order from the base end side,
The first line segment of each of the elastic wires is
the first bent portions are arranged at positions that are approximately equally spaced around a sheath extension line that connects the proximal binding tip and the distal binding tip and on an ellipsoidal surface that corresponds to the middle of the sheath extension line,
a center of curvature radius from the base end binding tip to the middle of the line segment is on the outside, and a center of curvature radius from the middle of the line segment to the first bent portion is on the inside, and the shape circumscribes the intake space;
The fourth line segment of each of the elastic wires is
The center of the radius of curvature from the distal binding tip to the third bent portion is on the outside and has a shape that circumscribes the intake space,
The second line segment to the fourth line segment of each of the elastic wires are
A basket-type endoscopic treatment instrument characterized in that it is disposed in correspondence with the distal half of the oval-spherical or spherical intake space.