WO2020195841A1

WO2020195841A1 - Convered stent

Info

Publication number: WO2020195841A1
Application number: PCT/JP2020/010566
Authority: WO
Inventors: 白濱　憲昭
Original assignee: 川澄化学工業株式会社
Priority date: 2019-03-25
Filing date: 2020-03-11
Publication date: 2020-10-01
Also published as: JPWO2020195841A1

Abstract

A covered stent (100) for implantation in the gastrointestinal tract, wherein said covered stent comprises a skeleton part (11) which is tube-shaped and can expand and contract in a radial direction approximately orthogonal to an axial direction, and a coating film part (12) which is attached along a circumferential surface of the skeleton part. A liquid permeation part (13), which is liquid permeable, is provided to at least a portion of the coating film part.

Description

Covered stent

The present invention relates to a covered stent.

Conventionally, it is placed in a stricture or obstruction formed in a living lumen such as the esophagus, stomach, duodenum, small intestine, large intestine, and digestive system lumen including the bile duct (hereinafter referred to as the digestive tract), and the lesion site is enlarged in diameter. There are known stents that maintain the patency of the living lumen (see, for example, Patent Document 1).

Japanese Patent No. 4651943

By the way, when a stent in which the peripheral surface of the stent skeleton is covered with a membrane (so-called covered stent) is used, the ingulose (the tissue at the lesion site passes through the gap of the stent skeleton and penetrates into the inside of the stent) into the stent. It is possible to suppress the occurrence of (a phenomenon that obstructs the living lumen). However, body fluids such as digestive juices that flow from the side cannot pass through the living lumen in which the stent is placed, and this may cause inflammation or the like in the living lumen.

An object of the present invention is to provide a covered stent that allows the passage of body fluid flowing from the side of the gastrointestinal tract while suppressing the generation of inglosose into the stent.

One aspect of the present invention is a covered stent indwelling in the gastrointestinal tract, which has a tubular shape and is attached to a skeletal portion that is substantially orthogonal to the axial direction and can be expanded and contracted in the radial direction along the peripheral surface of the skeletal portion. It is provided with a film portion to be formed. At least a part of the film portion is provided with a liquid-permeable portion having a liquid-permeable property.

According to the covered stent of one aspect of the present invention, the body fluid flowing from the side of the digestive tract can be passed into the stent while suppressing the generation of ingloth in the stent.

It is a perspective view which shows the schematic structure of the covered stent in one Embodiment. (A) is a sectional view taken along line II-II of FIG. 1, and (B) is a schematic view showing an enlarged portion surrounded by a broken line in FIG. 2 (A). It is a figure which shows an example of the use state in which the covered stent is indwelled in the gastrointestinal tract. (A) is a diagram schematically showing a covered stent in an expanded state, and (B) is a diagram schematically showing a state in which the covered stent is housed in a sheath.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In each figure described later, as one embodiment, a configuration example of a covered stent to be placed in the duodenum of the gastrointestinal tract is schematically shown. The shape, dimensions, etc. of the covered stent in the drawings are schematically shown, and do not show the actual shape, dimensions, etc.

FIG. 1 is a perspective view showing a schematic configuration of a covered stent in one embodiment. FIG. 2A is a cross-sectional view taken along line II-II of FIG. 1, and FIG. 2B is a schematic view showing an enlarged portion surrounded by a broken line in FIG. 2A. FIG. 3 is a diagram showing an example of a usage state in which a covered stent is placed in the gastrointestinal tract.

As shown in FIG. 3, the covered stent 100 of the present embodiment is placed at the lesion site of the duodenum 20, for example. Pancreatic juice from the pancreas 22 and bile from the bile 23 flow into the duodenum 20 via the papilla of Vater (duodenal papilla) 21 that opens into the inner wall of the duodenum 20. The covered stent 100 of the present embodiment has a function of passing digestive juice such as pancreatic juice and bile into the stent, as will be described later.

As shown in FIG. 1, the covered stent 100 includes a skeleton portion 11 and a coating portion 12 fixed to the skeleton portion 11, and has a tubular shape as a whole. Further, a bare portion 14 made of, for example, a metal skeleton is formed at one end of the covered stent 100 in the axial direction.
The bare portion 14 has a function of causing friction with the inner wall of the duodenum 20 when the covered stent 100 is placed and suppressing the displacement (migration) of the covered stent 100.

The covered stent 100 has a tubular flow path inside through which openings provided at both ends in the axial direction communicate with each other and through which an object flowing through the duodenum 20 passes.

The skeleton portion 11 is formed by, for example, spirally winding a thin metal wire (wire rod). For example, the skeleton portion 11 is formed by winding the thin metal wire spirally while bending so that peaks and valleys are alternately formed. The cross-sectional shape of the thin metal wire of the skeleton portion 11 is, for example, circular or elliptical.

The skeleton portion 11 is configured to be deformable so as to self-expand from a contracted state contracted inward in the radial direction to an expanded state expanded outward in the radial direction.
For example, as shown in FIGS. 4A and 4B described later, the skeleton portion 11 is deformed so as to extend in the axial direction when contracting inward in the radial direction, and axially when expanding outward in the radial direction. Transform to shorten. Then, as shown in FIG. 3, in the expanded state of the skeleton portion 11, the inner wall of the duodenum 20 is pressed by the outer surface of the covered stent 100.

Examples of the material constituting the fine metal wire of the skeleton portion 11 include known metals or metal alloys typified by Ni—Ti alloy (Nitinol), cobalt-chromium alloy, titanium alloy, stainless steel and the like. The skeleton portion 11 may be made of a material other than metal (for example, ceramic or resin).

Further, for example, the material of the skeleton portion 11 (Nitinol or the like), the cross-sectional area and cross-sectional shape of the thin metal wire of the skeleton portion 11 (circular wire rod such as a wire, or square wire rod by laser cutting), and the folding back of the skeleton portion 11 in the circumferential direction. The number of times and the folded shape (number of peaks and shape of peaks) and the spiral pitch of the skeleton 11 in the axial direction (the amount of skeleton per unit length of the covered stent 100) are the diameters of the digestive tract in which it is placed. Etc., it can be set to an appropriate value. Detailed description of these parameters will be omitted.

The film portion 12 is a tubular film body, and is attached to the skeleton portion 11 so as to close the gap portion of the skeleton portion 11. In this embodiment, as shown in FIG. 2A, the skeleton portion 11 is provided on the outer periphery of the coating portion 12. However, the film portion 12 may be attached to the outside of the skeleton portion 11, and the skeleton portion 11 may be sandwiched and covered from the inside and the outside by the two film portions 12.
Further, the skeleton portion 11 and the coating portion 12 may be fixed by any method such as adhesion, welding, sticking with tape, or sewing with a thread.

The film portion 12 includes at least a part of the liquid-permeable portion 13 made of a cloth having a liquid-permeable property. The liquid passing portion 13 is made of, for example, a woven fabric, knitted fabric or non-woven fabric made of a biocompatible fiber material, and has a plurality of fine mesh-shaped liquid passing holes 13a on the surface as shown in FIG. 2 (B). ing. The size of each liquid passage hole 13a is set to a size that allows digestive juice such as pancreatic juice and bile to pass through, but inhibits the invasion of cell tissue. Although FIG. 2B schematically shows an example in which the liquid passing portion 13 is made of a woven fabric, the liquid passing portion 13 may be a knitted fabric or a non-woven fabric as described above.

Examples of the fiber material forming the liquid passing portion 13 include a fluororesin such as PTFE (polytetrafluoroethylene) and a polyester resin such as polyethylene terephthalate.

The liquid passage portion 13 is provided at a position facing the papilla of Vater 21 (opening of the inner wall of the digestive tract) on the inner wall of the duodenum when the covered stent 100 is placed in the duodenum 20, for example. As a result, as shown in FIG. 2B, the digestive juice flowing into the duodenum 20 can be passed into the covered stent 100 through the liquid passage hole 13a of the liquid passage portion 13.
For example, when performing a procedure of inserting a tubular instrument (for example, an endoscope) into the bile duct or pancreatic duct from the inside of the covered stent 100 via the papilla of Vater 21, the gap of the liquid passage hole 13a is required. It is possible to respond by pushing out.

In the present embodiment, as shown in FIG. 1, the liquid passing portion 13 is partially formed in the middle of the covered stent 100 in the axial direction. Further, as shown in FIG. 2, the liquid passing portion 13 of the present embodiment is formed over the entire circumferential direction of the film portion 12. It is preferable to form the liquid passing portion 13 over the entire circumferential direction of the film portion 12 because the position of the papilla of Vater 21 and the liquid passing portion 13 in the circumferential direction becomes easy when the covered stent 100 is placed.
However, the position where the liquid passing portion 13 is formed is not limited to the above, and for example, the liquid passing portion 13 may be formed at the axial end of the covered stent 100. Alternatively, the entire film portion 12 may be used as the liquid passage portion 13. Further, the liquid passing portion 13 may be formed only in a part of the film portion 12 in the circumferential direction (for example, about half a circumference).

The film portion 12 having the liquid passing portion 13 is configured as follows. For example, the film portion 12 may be integrally formed of a biocompatible fiber material woven fabric, knitted fabric, or non-woven fabric, and the entire film portion 12 may be used as the liquid passage portion 13.
Further, the film portion 12 having the liquid permeability is subjected to a surface treatment (for example, press working, formation of a biocompatible film, etc.) to reduce the liquid permeability in a region other than the liquid passage portion 13. You may. As a result, the liquid passing portion 13 can be selectively formed on the portion of the film portion 12 that is not subjected to the surface treatment.
Further, the liquid-permeable portion 13 may be partially formed on the film-coated portion 12 by connecting fabrics having different liquid-permeable properties to produce the film-coated portion 12. In the above configuration, a sheet material other than the cloth may be used for the region other than the liquid passing portion 13. Alternatively, when the film portion 12 is formed of a cloth, the knitting method and the weaving method are set in the region of the liquid passing portion 13 and the region other than the liquid passing portion 13 (the portion having a lower liquid passing property than the liquid passing portion 13), respectively. The liquid passing portion 13 may be partially formed on the film portion 12 by changing the material or changing the material used for the liquid passing portion 13 and the material used for the portion other than the liquid passing portion 13.

Further, the film portion 12 is processed to regulate the axial extension of the skeleton portion 11. By performing this processing, the skeleton portion 11 is constrained by the film portion 12 whose axial extension is restricted, and it becomes difficult to extend in the axial direction. As a result, the degree of axial extension (shortening rate) of the covered stent 100 between the contracted state and the expanded state is also reduced.

An example of the above processing is press processing in which the film portion 12 is stretched in the axial direction using a heated roller. It is preferable that the above press working has a strength that can regulate the axial extension of the skeleton portion 11, but has a strength that does not impair the radial expansion / contraction property of the covered stent 100.
For example, the above press working may be applied to the entire circumferential direction of the film portion 12, or may be applied to a part of the film portion 12 in the circumferential direction (for example, at predetermined angles in the circumferential direction).

Further, from the viewpoint of restricting the axial extension of the skeleton portion 11, the above press working is preferably performed from one end to the other end in the axial direction along the axial direction of the covered stent 100.
Here, when the liquid passing portion 13 is formed in the entire circumferential direction of the film portion 12, if the press working is performed from one end to the other end in the axial direction of the covered stent 100, the liquid passing portion 13 is also passed. Press processing to reduce the liquid property will be performed. In such a case, the range of the liquid passing portion 13 may be press-processed with a strength that does not impair the required liquid passing property.

Next, the accommodation state of the covered stent 100 in the sheath 200 will be described with reference to FIGS. 4 (A) and 4 (B). FIG. 4A is a diagram schematically showing a covered stent 100 in an expanded state, and FIG. 4B is a diagram schematically showing a state in which the covered stent 100 is housed in the sheath 200.
The covered stent 100 is introduced into the duodenum 20 while being housed in the sheath 200 (see FIG. 4B). The covered stent 100 housed in the sheath 200 is in a contracted state in which the skeleton portion 11 is contracted. The covered stent 100 is, for example, carried to a narrowed portion of the duodenum 20 and then released from the sheath 200, and deforms into an expanded state in which the skeleton portion 11 is expanded. At this time, the covered stent 100 is placed so that the liquid passage portion 13 faces the papilla of Vater 21 (opening of the inner wall of the digestive tract) on the inner wall of the duodenum.

As shown in FIG. 4 (B), the covered stent 100 was contracted radially inward and extended axially in the contracted state housed in the sheath 200 as compared with the expanded state of FIG. 4 (A). Become in a state. That is, the covered stent 100 has an axial length L2 in the contracted state housed in the sheath 200 shown in FIG. 4 (B) as compared with the axial length L1 in the expanded state shown in FIG. 4 (A). become longer.
Here, in the covered stent 100 of the present embodiment, the axial extension of the skeleton portion 11 attached to the coating portion 12 is restricted by the press working applied to the coating portion 12. Therefore, the axial length L2 when housed in the sheath 200 is shorter than that in the case where the press working is not performed.

As described above, in the covered stent 100 of the present embodiment, since the skeleton portion 11 is covered with the coating portion 12, it is possible to suppress the generation of ingrown in the stent.
Further, a part of the film portion 12 is provided with a liquid-passing portion 13 made of a cloth having a liquid-permeable property. Therefore, the digestive juice flowing from the papilla of Vater 21 can be passed into the covered stent 100. Therefore, according to the present embodiment, the covered stent is a covered stent that allows the passage of digestive juice flowing from the side of the duodenum while suppressing the generation of ingloth in the stent.

Further, in the covered stent 100 of the present embodiment, the coating portion 12 is subjected to processing (for example, press processing) to regulate the axial extension of the skeleton portion 11. Therefore, the axial length L2 of the covered stent 100 in the contracted state is relatively shorter than in the case of using another film portion that has not been processed to regulate the axial extension. As a result, the contact area between the outer surface portion of the covered stent 100 and the inner surface portion of the sheath 200 can be made relatively small, and the resistance at the time of discharge from the sheath 200 can be reduced. Therefore, the covered stent 100 can be properly released from the sheath 200.

Further, the axial length L2 of the covered stent 100 in the contracted state can be made relatively small. As a result, the shortening rate of the covered stent 100 in the axial direction at the time of stent placement can be reduced, and the covered stent 100 can be suitably placed at a desired placement site of the duodenum.

When the covered stent is released from the sheath by pulling the sheath toward the hand, the covered stent further extends in the axial direction due to the frictional resistance between the inner surface of the sheath and the outer surface of the covered stent, and is released. It is conceivable that the resistance will increase. On the other hand, in the present embodiment, since the coating portion 12 is subjected to the above processing, it is possible to prevent the covered stent 100 from further extending in the axial direction. Therefore, it is possible to suppress an increase in resistance at the time of release.

Although the invention made by the present inventor has been specifically described above based on the embodiment, the present invention is not limited to the above embodiment and can be changed without departing from the gist thereof.

For example, the skeleton portion 11 may be formed by laser processing (laser cutting) one metal pipe (for example, a pipe made of Ni—Ti alloy).

Further, in the above embodiment, the film portion 12 is made of a woven fabric, a knitted fabric, a non-woven fabric, or the like having a liquid-permeable property, but the present invention is not limited to this, and is, for example, a non-liquid-permeable material. It may be composed of a membrane body. Specifically, although not shown, the skeleton portion 11 may be dipped into a predetermined solution (for example, a silicone solution) to form a film body. In this case, by forming fine liquid passage holes in the film body, the film portion 12 provided with the liquid passage portion 13 is formed.

Further, in the above embodiment, the covered stent 100 placed in the duodenum has been illustrated, but the present invention is not limited to this. For example, the stent may be placed in a gastrointestinal tract other than the duodenum, or may be placed in a living lumen other than the gastrointestinal tract. In this case as well, body fluids such as digestive juices flowing from the side of the living lumen can be passed into the stent while suppressing the generation of ingloth in the stent.
In the case of a stent placed in the digestive tract other than the duodenum, the substance flowing through the digestive tract may pass through, for example, food that has not been digested at all, food that has been partially decomposed, or food that has been partially decomposed. The state of the substance does not matter, including undigested substances (for example, stool).

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

100 Covered stent 11 Skeleton part 12 Coating part 13 Liquid passage part

Claims

A covered stent that is placed in the gastrointestinal tract
A skeleton that has a tubular shape and can be expanded or contracted in the radial direction that is approximately orthogonal to the axial direction.
A film portion attached along the peripheral surface of the skeleton portion is provided.
A covered stent in which a liquid-permeable portion having a liquid-permeable property is provided in at least a part of the film portion.
The covered stent according to claim 1, wherein the liquid passage portion is provided at a position facing the opening of the inner wall of the digestive tract when the covered stent is placed in the digestive tract.
The covered stent according to claim 1 or 2, wherein the film portion is processed to regulate the axial extension of the skeleton portion.
The covered stent according to claim 3, wherein the region of the liquid-permeable portion of the film portion is subjected to the processing for restricting the axial extension of the skeleton portion while maintaining the liquid-permeable property. ..
The film portion including the liquid passing portion is made of a cloth.
From claim 1, the liquid passing portion provided in a part of the film portion is partially formed by a different type of fabric or a different surface treatment from the portion of the film portion excluding the liquid passing portion. The covered stent according to any one of claims 4.