JP7494443B2 - Anchor Stent - Google Patents

Description

The present invention relates to an anchor stent that connects biological organs.

In general, when the bile duct or pancreatic duct is blocked due to gallstones, tumors, inflammation, etc., bile duct drainage or pancreatic duct drainage is performed to drain bile or pancreatic juice from the body. Furthermore, when access to the papilla of Vater using an endoscope with a catheter is difficult due to stenosis caused by a tumor, anchor stents are sometimes used to connect multiple vital organs (between organs) to form a bypass through which bile and pancreatic juice can pass.

For example, Patent Document 1 discloses an anchor stent (referred to in the document as a bypass stent) that can connect organs while suppressing their migration.
Specifically, the anchor stent disclosed in Patent Document 1 comprises a long and slender tubular body (referred to as a main body in the document) and hooking parts provided at both ends of the tubular body and formed of elastic linear members. The distal ends of the hooking parts come into contact with the inner wall of the tubular organ, thereby suppressing the movement of the anchor stent.

JP 2015-66221 A

In conventional stents, the tubular body is formed in a straight tube shape, so if, for example, the radial size of the insertion hole formed in an organ varies in the longitudinal direction, the load applied from the body tissue cannot be distributed to the tubular body, and the load tends to be concentrated on the hooking portion.
In this regard, there has been a demand for a device that can reduce the load imbalance, suppress the reaction force applied from the hooking portion to the body tissue, and maintain the placement of the stent in an optimal manner.
The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an anchor stent that can favorably maintain the placement of a stent.

The anchor stent of the present invention is an anchor stent comprising a long tubular body, two flanges spaced apart in the longitudinal direction of the tubular body, and at least a resin film constituting the tubular body, and is characterized in that the tubular body is passed through insertion holes provided in adjacent biological organs, and the two flanges engage with each other to connect the biological organs, and that each of the two flanges has an opening formed therein that connects the internal space of the tubular body to the outside of the respective flanges, the diameter of the tubular body differs in the longitudinal direction, and the maximum diameter of the tubular body is smaller than the diameter of either of the two flanges.

The anchor stent of the present invention having the above configuration can provide an anchor stent that can maintain the placement of the stent in an optimal manner.

FIG. 2 is a schematic side view showing the anchor stent according to the first embodiment. FIG. 2 is an explanatory diagram showing a biological organ to which an anchor stent is connected. FIG. 6 is a schematic side view showing an anchor stent according to a second embodiment. FIG. 13 is a schematic side view showing an anchor stent according to a third embodiment. FIG. 13 is a schematic side view showing an anchor stent according to a fourth embodiment. FIG. 13 is a schematic side view showing an anchor stent according to a fifth embodiment.

Hereinafter, an anchor stent according to an embodiment of the present invention will be described with reference to the drawings.
The embodiment described below is merely an example for facilitating understanding of the present invention, and is not intended to limit the present invention. In other words, the shapes, dimensions, arrangements, and other aspects of the components described below may be modified or improved without departing from the spirit of the present invention, and the present invention naturally includes equivalents thereof.
In addition, in all drawings, similar components are given similar symbols and duplicated explanations are omitted as appropriate.

First Embodiment
＜Overview＞
First, an overview of the anchor stent of the present invention will be described with reference to Fig. 1 and Fig. 2, taking the anchor stent 21 according to the first embodiment as an example. Fig. 1 is a schematic side view showing the anchor stent 21 according to the first embodiment, and Fig. 2 is an explanatory diagram showing a biological organ (organ) to which the anchor stent 21 is connected. Note that Fig. 2 shows an example of a biological organ that can be connected by the anchor stent 21, and does not explain that a plurality of anchor stents 21 are used simultaneously. Also, in Fig. 2, the flange portions 21b and 21ba of the anchor stent 21 are omitted, and the cylindrical body 21a is shown simplified as a straight cylinder.

The anchor stent 21 according to this embodiment includes a long cylindrical body 21a, two flanges 21b, 21ba spaced apart from each other in the longitudinal direction of the cylindrical body 21a, and at least a resin film 21c constituting the cylindrical body 21a. The cylindrical body 21a is passed through insertion holes 5a, 7a provided in adjacent biological organs (e.g., the gallbladder 5 and the duodenum 7), respectively. With the cylindrical body 21a passed through the insertion holes 5a, 7a, the anchor stent 21 connects biological organs (e.g., the gallbladder 5 and the duodenum 7) by engaging the two flanges 21b, 21ba with the biological organs (e.g., the inner wall of the gallbladder 5 and the inner wall of the duodenum 7).
The two flange portions 21b, 21ba are each formed with an opening 21f, 21fa that communicates the internal space of the cylindrical body 21a with the outside of the flange portion 21b, 21ba.
The diameters (diameters d1, d2) of the cylindrical body 21a are different in the longitudinal direction, and the maximum diameter of the cylindrical body 21a is smaller than the diameters (diameter D) of both of the two flange portions 21b, 21ba.

The above configuration allows the flanges 21b and 21ba to be engaged with the edge surface of the insertion hole of the biological organ, while also allowing the tubular body 21a to be easily engaged with the inner wall surface of the insertion hole, which has a different diameter in the longitudinal direction corresponding to the shape of the tubular body 21a. This further enhances the anchor function of the anchor stent 21, and makes it possible to maintain the position of the anchor stent 21 in an optimal manner.

The above "two flange portions" refers to the two flange portions that are spaced the largest apart in the longitudinal direction of the tubular body, and the anchor stent may be provided with other flange portions in addition to these flange portions.
The "opening" formed in the flange portion is not limited to being formed by the extension of the inner cavity of the cylindrical body.
In other words, the "hole" may be connected to the inner cavity of the cylindrical body so as to allow the flow of fluids. Specifically, even if the flange portion is provided to block the inner cavity of the cylindrical body, the blocking portion may be made of a mesh-like wire, and the openings of the wire that allow the flow of fluids are also included in the "hole".
Furthermore, the above-mentioned "insertion hole" may be a through hole or a bottomed hole. When the insertion hole is a bottomed hole, the end of the anchor stent is inserted into a bottomed hole provided in the tissue of a biological organ, and functions, for example, to pass tissue fluid exuding from the tissue to an adjacent biological organ.
In addition, the "diameter" of a cylindrical body or a flange portion means the long diameter of an ellipse and the diagonal length of a rounded corner shape, and refers to the length of the longest line segment perpendicular to the central axis that connects the central axis with a part of the outer surface.

As shown in FIG. 2 , the anchor stent 21 is intended to connect multiple biological organs (between organs) to form a bypass through which bile and pancreatic juice can pass when access to the Vater's papilla (not shown) via an endoscope is difficult due to a tumor T or the like.
Specifically, the anchor stent 21 has a tubular body 21a that is passed through insertion holes 2a, 3a, 4a, 5a, 6a, and 7a provided in adjacent biological organs, namely, the stomach 2 and liver 3, the stomach 2 and pancreatic duct 6, the bile duct 4 and duodenum 7, or the gallbladder 5 and duodenum 7, thereby connecting these biological organs.

<Configuration>
Next, the configuration of the anchor stent 21 will be described in detail with reference to Fig. 1. The anchor stent 21 has a tubular body 21a and two flange portions 21b, 21ba at both ends of the tubular body 21a.
For example, the anchor stent 21 is formed by joining together a tubular body 21a, which is a mesh formed into a frustum shape by laser cutting, and a cylindrical mesh before the flanges 21b and 21ba are formed in the initial stage. After that, the cylindrical mesh is deformed to form the flanges 21b and 21ba, and the anchor stent 21 is formed by applying a heat treatment to maintain the shape.

Alternatively, the anchor stent 21 may be formed by weaving together metal wires having shape memory properties, such as Nitinol, and subjecting them to a heat treatment to retain their shape.
By weaving such metal wires, it is possible to form the tubular body 21a and the flange portions 21b, 21ba integrally and continuously, making it possible to form an anchor stent 21 with better shape retention.

The cylindrical body 21a and the two flanges 21b, 21ba of the anchor stent 21 according to this embodiment are configured to include, as an example, a silicone resin film 21c. The inner diameter of the internal space 21e on the flange 21b side and the inner diameter of the opening 21f, and the inner diameter of the internal space 21e on the flange 21ba side and the inner diameter of the opening 21fa are formed to be the same (including approximately the same) inner diameter.

For example, when the mesh (wire) is immersed in molten resin to form the resin film 21c, the thickness of the cylindrical body 21a and the thickness of the flanges 21b, 21ba may not be uniform between the part covering the mesh (wire) and the part not covering it. In such a case, the above-mentioned "the inner diameter of the internal space 21e on the flange 21b side and the inner diameter of the opening 21f, and the inner diameter of the internal space 21e on the flange 21ba side and the inner diameter of the opening 21fa are the same" means that the parts covering the mesh (wire) and the parts not covering it are the same.
In other words, in any cross section including the axis of the anchor stent 21, between the tubular body 21a and the flange portions 21b, 21ba, virtual lines connecting the axial sides of multiple parts covering the mesh (wire) or virtual lines connecting parts not covering the mesh (wire) are formed continuously.
This configuration allows bile, pancreatic juice, etc. to flow smoothly through the internal space 21e and the openings 21f, 21fa.

In particular, the cylindrical body 21a according to this embodiment has a first portion 21aa connected to the flange portion 21b on one side, and a second portion 21ab connected to the flange portion 21ba on the other side.
In the cylindrical body 21a, the first portion 21aa and the second portion 21ab are formed to have different diameters. Specifically, the diameter d1 of the first portion 21aa is different from and larger than the diameter d2 of the second portion 21ab.

According to the above configuration, when the insertion holes (insertion holes 5a, 7a, etc.) are formed in different sizes due to differences in the size of organs that are biological organs, an anchor stent 21 having a shape suitable for the shape of the insertion hole can be selected.
Therefore, when the tubular body 21a is passed through the insertion hole, the tubular body 21a can be adhered closely to the wall surface of the insertion hole, making the anchor stent 21 less likely to shake and less likely to come off the insertion hole of the biological organ.

In addition, although the flange portions 21b, 21ba in this embodiment are shown diagrammatically as having an angular shape, it goes without saying that a rounded, chamfered shape without corners is preferable for placement within the living body, and the same is true for the other embodiments.
In addition, the diameter of the cylindrical body is not limited to the above-mentioned configuration in which the diameter of the first portion 21aa connected to the flange portion 21b and the diameter of the second portion 21ab connected to the flange portion 21ba are different, as long as they are different in the longitudinal direction. This will be described in detail in a later embodiment.

Second Embodiment
Next, details of the configuration of the anchor stent 22 according to the second embodiment will be described with reference to Fig. 3. Fig. 3 is a schematic side view showing the anchor stent 22 according to the second embodiment.
The tubular body 22a, which is a characteristic configuration of the anchor stent 22, has a curved portion 22g that is provided between two flange portions 22b, 22ba and extends in the longitudinal direction while being curved in the radial direction.
The above-mentioned "curved in the radial direction" means that the thickness is contracted in the direction approaching the central axis, or the thickness is expanded in the direction away from the central axis.
The above-mentioned "extending in the longitudinal direction" means extending including a longitudinal component.
Furthermore, the above-mentioned "curved portion" is not limited to a portion that is smoothly bent to form a complete curved surface, but also includes a bent portion (for example, a portion that is formed in a stepped shape).

According to the above configuration, the cylindrical body 22a has the curved portion 22g, so that it is possible to apply resistance in many directions to the biological organ that abuts against the curved portion 22g. This makes it possible to prevent a load from being applied to the flange portions 22b, 22ba from the edge of the insertion hole in the direction in which the flange portions 22b, 22ba are removed.

In particular, the two flange portions 22b, 22ba according to this embodiment are formed to have different diameters (D1, D2).
According to the above configuration, by selecting flange portions 22b, 22ba of different diameters to match the tubular body 22a having a different diameter in the longitudinal direction, or the edge of the insertion hole of the biological organ to be engaged, the anchor stent 22 can be suitably engaged with the biological organ.

In particular, the flange portion 22b on one side according to this embodiment is formed to have a diameter D1 larger than the diameter D2 of the flange portion 22ba on the other side.
In addition, in the cylindrical body 22a, the first portion 22aa connected to the flange portion 22b on one side is formed with a diameter d1 that is larger than the diameter d2 of the second portion 22ab connected to the flange portion 22ba on the other side. In other words, the cylindrical body 22a is formed so that the diameter gradually increases from the flange portion 22ba side toward the flange portion 22b side.
According to the above configuration, the flange portion 22ba on the other side (smaller diameter side) can ensure an engagement depth with the adjacent biological organ that is approximately the same as that of the flange portion 22b on one side (larger diameter side).

Furthermore, it is preferable that the difference between the diameter D2 of the flange portion 22ba and the diameter d2 of the second portion 22ab of the tubular body 22a is greater than the difference between the diameter D1 of the flange portion 22b and the diameter d1 of the first portion 22aa of the tubular body 22a.
As described above, the diameter of the flange portion 22ba gradually increases from the flange portion 22b, so that the load applied from the cylindrical body 22a to the wall surface of the insertion hole of the biological organ makes it easier for the biological organ to move toward the flange portion 22ba. Therefore, a larger load is more likely to be applied from the edge of the insertion hole of the biological organ to the flange portion 22ba side than to the flange portion 22b. According to the above configuration, even if the biological organ moves relative to the anchor stent 22 due to the load, the engagement by the flange portion 22ba is easily maintained, and it is possible to preferably prevent the biological organ from coming off the anchor stent 22.

Also, for example, it is preferable that the flange portion 22ba on the other side has a higher bending rigidity than the flange portion 22b on the one side.
The above-mentioned "bending rigidity" more specifically refers to the bending rigidity per unit length in the circumferential direction.
According to the above configuration, since the diameter is small, the contact area with the edge of the insertion hole is relatively small, which prevents the flange portion 22ba on the other side, which is easily subjected to pressure in the removal direction, from deforming, and prevents the flange portion 22ba from coming out of the insertion hole of the biological organ.
Other than the above description, the anchor stent 21 and the anchor stent 22 are the same, and therefore the description thereof will be omitted. The same applies to the following embodiments.

Third Embodiment
Next, details of the configuration of the anchor stent 23 according to the third embodiment will be described with reference to Fig. 4. Fig. 4 is a schematic side view showing the anchor stent 23 according to the third embodiment.
The curved portion provided on the cylindrical body 23a of the anchor stent 23 according to this embodiment is a constricted portion 23g that is constricted radially inward. The cylindrical body 23a is configured to have a curved outer surface such that the diameter of the cylindrical body 23a is gradually reduced toward the center in the longitudinal direction by the constricted portion 23g.

According to the above configuration, a load having a component directed from the constricted portion 23g toward the center of the tubular body 23a is applied to the adjacent biological organ held by the anchor stent 23. This allows the load to be guided toward the small diameter side (the center side in the longitudinal direction) of the constricted portion 23g. This prevents the load from being applied from the biological organ to the flange portions 23b, 23ba at both ends in the longitudinal direction, and prevents the anchor stent 23 from coming out of the insertion hole of the biological organ.

Fourth Embodiment
Next, details of the configuration of the anchor stent 24 according to the fourth embodiment will be described with reference to Fig. 5. Fig. 5 is a schematic side view showing the anchor stent 24 according to the fourth embodiment.
The tubular body 24a of the anchor stent 24 in this embodiment is formed roughly tapered and has a first portion 24aa connected to the flange portion 24b on one side, and a second portion 24ab connected to the flange portion 24ba on the other side.
In the cylindrical body 24a, the first portion 24aa is formed to have a larger diameter than the second portion 24ab.

The cylindrical body 24a has curved portions 24g on its outer surface. The curved portions 24g are provided in succession in the longitudinal direction of the cylindrical body 24a, and the overall surface shape is wavy.
As described above, since the entire surface shape of the plurality of curved portions 24g is wavy, it is easy to increase the contact area with the inner wall surface of the insertion hole of the biological organ, and therefore the holding ability can be improved.
Furthermore, by providing the plurality of curved portions 24g, even if the biological organs are located far away from the flange portions 24b and 24ba, a frictional force from the curved portions 24g at those positions can be applied to the inner wall surface of the insertion hole of the biological organ. This frictional force can limit the movement of the anchor stent 24.
In the above embodiment, the curved portion 24g is described as being provided in a continuous manner, but the curved portion according to the present invention is not limited to this configuration. The curved portion 24g may be provided intermittently in the longitudinal direction of the cylindrical body 24a, as will be described in detail later.

Fifth Embodiment
Next, details of the configuration of the anchor stent 25 according to the fifth embodiment will be described with reference to Fig. 6. Fig. 6 is a schematic side view showing the anchor stent 25 according to the fifth embodiment.
The tubular body 25a of the anchor stent 25 according to this embodiment is formed in a generally straight tubular shape. The tubular body 25a has curved portions 25g on its outer surface, and the curved portions 25g are provided in a plurality of continuous portions in the longitudinal direction of the tubular body 25a, so that the overall surface shape is wavy.

As described above, the overall surface shape of the multiple curved portions 25g is wavy, which makes it easier to increase the contact area with the inner wall surface of the insertion hole of the biological organ, thereby improving the retention. Furthermore, by providing multiple curved portions 25g, even if biological organs that are far apart are located away from the flange portions 25b and 25ba, it is possible to apply a frictional force from the curved portions 25g at that position to the inner wall surface of the insertion hole of the biological organ. This frictional force can limit the movement of the anchor stent 25.

The present invention is not limited to the above-described embodiments.
5 and 6, the curved portions 24g, 25g are formed continuously in a plurality of positions by connecting the ends of adjacent curved portions 24g, 25g in the longitudinal direction of the cylindrical bodies 24a, 25a. However, the present invention is not limited to such a configuration, and the curved portions 24g, 25g may be formed discontinuously by providing flat portions (flat surface portions or inclined surface portions) between the curved portions 24g, 25g.
For example, they may be provided only in the vicinity of the flange portions 24b, 24ba, 25b, and 25ba, and may not be provided on the central side.
According to this configuration, the curved portions 24g, 25g in the vicinity of the flanges 24b, 24ba, 25b, 25ba can ensure engagement with the wall surface of the insertion hole of the biological organ, and further, since no curved portion is formed in the central portion of the tubular bodies 24a, 25a, the outer and inner surfaces can be easily made flat, allowing fluids to pass smoothly through the anchor stent.

In addition, a flat portion with a width close to the thickness of the biological organ may be formed between the curved portion 24g and the flange portions 24b, 24ba, or between the curved portion 25g and the flange portions 25b, 25ba. With this configuration, it is possible to sandwich the wall of the biological organ between the curved portion 24g and the flange portions 24b, 24ba, or between the curved portion 25g and the flange portions 25b, 25ba. This makes it possible to suppress relative movement (vibration) of the biological organ, and to appropriately place the anchor stents 24, 25.

In addition, although the inner surfaces of the cylindrical bodies 24a and 25a shown in Figures 5 and 6 are shown to have projections and recesses, the thickness of the resin film may be changed locally to fill the recesses. In this way, it is possible to prevent some of the fluid from accumulating in the recesses.

The above embodiment encompasses the following technical ideas.
(1) a long cylindrical body;
Two flange portions provided at an interval in the longitudinal direction of the cylindrical body;
A resin film that constitutes at least the cylindrical body,
The tubular body is inserted into insertion holes provided in adjacent biological organs, and the two flange portions are engaged with each other to connect the biological organs,
Each of the two flanges has an opening formed therein that communicates an internal space of the cylindrical body with an outside of the corresponding flange,
The diameter of the cylindrical body varies in the longitudinal direction,
An anchor stent, wherein the maximum diameter of the tubular body is smaller than the diameters of either of the two flange portions.
(2) The anchor stent according to (1), wherein the tubular body has a curved portion provided between the two flange portions and extending in the longitudinal direction while being curved in the radial direction.
(3) The anchor stent according to (2), wherein the curved portions are provided in a plurality in the longitudinal direction of the tubular body, and the overall surface shape is wavy.
(4) An anchor stent according to (2) or (3), wherein the curved portion is a constricted portion that is constricted radially inward.
(5) The cylindrical body has a first portion connected to the flange portion on one side and a second portion connected to the flange portion on the other side,
The anchor stent according to any one of (1) to (4), wherein the first portion and the second portion of the tubular body are formed with different diameters.
(6) An anchor stent described in any one of (1) to (5), wherein the two flange portions are formed with different diameters.
(7) The flange portion on one side is formed to have a larger diameter than the flange portion on the other side,
The anchor stent according to (6) which cites (5) above, wherein the first portion is formed with a larger diameter than the second portion.
(8) The anchor stent according to (7), wherein the flange portion on the other side has a bending rigidity higher than that of the flange portion on the one side.

2. Stomach (vital organ)
2a Insertion hole 3 Liver (living organ)
3a Insertion hole 4 Bile duct (biological organ)
4a Insertion hole 5 Gallbladder (living organ)
5a Insertion hole 6 Pancreatic duct (biological organ)
6a Insertion hole 7 Duodenum (living organ)
7a Insertion hole 21 Anchor stent 21a Cylindrical body 21aaa First portion 21ab Second portion 21b, 21ba Flange portion 21c Resin film 21e Internal space 21f, 21fa Opening 22 Anchor stent 22a Cylindrical body 22aaa First portion 22ab Second portion 22b, 22ba Flange portion 22g Curved portion 23 Anchor stent 23a Cylindrical body 23b, 23ba Flange portion 23g Neck portion (curved portion)
24 Anchor stent 24a Cylindrical body 24aa First portion 24ab Second portion 24b, 24ba Flange portion 24g Curved portion 25 Anchor stent 25a Cylindrical body 25g Curved portion T Tumor

Claims (6)

A long cylindrical body,
Two flange portions provided at an interval in the longitudinal direction of the cylindrical body;
A resin film that constitutes at least the cylindrical body,
The tubular body is inserted into insertion holes provided in adjacent biological organs, and the two flange portions are engaged with each other to connect the biological organs,
Each of the two flanges has an opening formed therein that communicates an internal space of the cylindrical body with an outside of the corresponding flange,
The diameter of the cylindrical body varies in the longitudinal direction,
The maximum diameter of the cylindrical body is smaller than the diameters of both of the two flange portions,
the cylindrical body has a first section connected to the flange portion on one side and a second section connected to the flange portion on the other side, and expands in diameter from the second section toward the first section, the flange portion on the one side is disposed outside the first section in the longitudinal direction, and is formed to have a larger diameter than the first section ,
The anchor stent is characterized in that the two flange portions are respectively terminated at both ends in the longitudinal direction of the tubular body . The anchor stent according to claim 1, wherein the tubular body has a curved portion disposed between the two flange portions and extending in the longitudinal direction while being curved in the radial direction. The anchor stent according to claim 2, wherein the curved portions are provided in a plurality in the longitudinal direction of the tubular body, and the overall surface shape is wavy. The anchor stent according to any one of claims 1 to 3, wherein the two flange portions are formed with different diameters. The flange portion on one side is formed to have a larger diameter than the flange portion on the other side,
The anchor stent according to claim 4 , wherein the first portion is formed with a larger diameter than the second portion. The anchor stent according to claim 5, wherein the flange portion on the other side has a higher bending stiffness than the flange portion on the one side.

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