JP6705025B2 - Stent - Google Patents

Description

The present invention relates to, for example, a tubular organ such as a bile duct, a ureter, a trachea, and a blood vessel, and a stent left in a body such as a body cavity.

For a long time, a stent was placed in a stenosis or occlusion that has occurred in the body such as tubular organs such as the bile duct, ureter, trachea, blood vessel, or esophagus, or body cavity, and the stenosis or occlusion was expanded, and bile Treatments using a stent have been performed, such as facilitating the flow of blood, blood, etc., or indwelling a stent at a site where an aneurysm has occurred to prevent its rupture.

For example, Patent Document 1 described below describes a stent having a plurality of components having a substantially rhombic shape, a substantially circular shape, a substantially rectangular shape, and a connecting portion that connects these constituent elements in an axial direction. There is. The connecting portion has a substantially S-shaped bent shape having a mountain-shaped bent portion on one axial side of the stent and a valley-shaped bent portion on the other axial side of the stent. There is.

Further, when a stent is placed in a tubular organ such as a bile duct, the lumen of the stent may become blocked with the passage of time due to bodily fluid such as bile or proliferation of cancer cells. Sometimes it was necessary to collect In this case, for example, one end of the stent placed in the tubular organ is grasped with forceps or a snare, and then pulled to pull the stent off the inner wall of the tubular organ, and then to further pull the stent. The stent is pulled out from the tubular organ.

As a stent that can be recovered from the body as described above, for example, Patent Document 2 below has a plurality of strut portions that are bent in a zigzag shape and have an annular shape, and a bridge portion that connects each strut portion in the axial direction. When each bent portion of each strut portion protruding toward the one end side of the stent is formed as a mountain portion, all mountain portions of each strut portion are connected to the bridge portion, and a plurality of them are bundled by the bridge portion. , A stent is described. Further, the bridge portion is formed by bundling a plurality of linear frames, and each frame is connected to all of the mountain portions of the strut portion.

JP 2001-104488 A International publication WO2016/129551

In the stent of Patent Document 2, since the bridge portion is composed of a linear frame, when the stent is placed in a bent tubular organ or the like, the linear frames may be bent and the bridge portion may be easily kink. There was a nature.

On the other hand, in the stent of Patent Document 1, since the connecting portion that connects the plurality of constituent elements has a substantially S-shaped bent shape, the connecting portion is relatively long and has some flexibility. Therefore, it is difficult to kink. However, when the stent is pulled from one end side in order to pull out the stent from the inside of the body, the bent portion of the connecting portion may be easily caught on the inner wall of the body.

Therefore, an object of the present invention is to provide a stent in which a stent placed in the body can be smoothly extracted from the body and the bridge portion is less likely to be kinked.

In order to achieve the above-mentioned object, the present invention is bent in a zigzag shape and is formed in a ring shape by connecting both ends thereof, or a plurality of frame-shaped bodies bent in a predetermined shape are arranged in the circumferential direction. A strut having a plurality of strut parts formed in an annular shape by connecting with each other, and a bridge part connecting a plurality of these strut parts in the axial direction, wherein each strut part has one end side of the stent. When the projecting portion projecting on the other side is a mountain portion and the projecting portion projecting on the other end side is a valley portion, all the mountain portions of each strut portion except the strut portion located at the head on the one end side are the bridge portions. , And are bundled by a plurality of by the bridge portion, the strut portion adjacent to the one end side, is connected to the valley portion or the mountain portion, the valley portion of each strut portion, The bridge part has a part that is not connected to the bridge part, and the bridge part has a binding part that is bundled into one on the way to the one end side, and the binding part is the one end side. Is connected to the valley portion or the mountain portion of the strut portion adjacent to, and the binding portion has at least two bending portions that bend in one circumferential direction and the other circumferential direction of the stent. In addition, all the tops of the respective bent portions are configured to face the other end side.

According to the present invention, in a body such as a tubular organ, in a state where the stent is inserted from the other end side and left in place, one end side of the stent is grasped and pulled by forceps or a snare in order to recover the stent, All the crests of each strut except the top strut are pulled through the bridge, and the crests tend to converge and reduce in diameter, making it difficult for them to get caught on the inner wall of the body and strut parts. The binding portion of the bridge portion that connects the two has at least two bent portions that bend in one circumferential direction and the other circumferential direction of the stent, and all the tops of each bent portion are on the other end side of the stent. Since it is configured to face, it is possible to prevent the top of the bent portion from getting caught on the inner wall of the body when the stent is collected, and the stent can be smoothly extracted from the body. Since the binding portion has at least two bending portions that bend in one circumferential direction and the other circumferential direction of the stent, the binding portion can be secured for a long time, resulting in increased flexibility. Therefore, it is possible to make it difficult to kink the bridge portion.

1A shows a first embodiment of a stent according to the present invention, FIG. 1A is a perspective view of a stent main body constituting the stent, and FIG. 1B is a perspective view of the stent main body covered with a cover. It is a development view of the main stent body which constitutes the same stent. It is an A section enlarged view of FIG. It is sectional drawing of the same stent. It is an expansion explanatory view showing the state at the time of pulling out the same stent from the body. It is explanatory drawing which shows the state which left the same stent in the body. It is explanatory drawing which shows the state at the time of pulling out the same stent from a body. Fig. 2 shows a second embodiment of the stent according to the present invention, and is an enlarged development view of a main part of a stent body constituting the stent. It is explanatory drawing of the state which reduced the diameter of the same stent. FIG. 7 shows a third embodiment of the stent according to the present invention, and is an enlarged development view of a main part of a stent body constituting the stent. It is explanatory drawing of the state which reduced the diameter of the same stent. It is a 4th embodiment of the stent concerning the present invention, and is a principal part expansion deployment view of a main part of a stent which constitutes the same stent.

Hereinafter, a first embodiment of the stent according to the present invention will be described with reference to FIGS.

As shown in FIG. 1( a ), the stent 10 of this embodiment has a stent body 20 having a substantially cylindrical shape with both ends open, and further, as shown in FIG. 1( b ), a stent An inner cover 60 is coated on the inner side of the main body 20, and an outer cover 65 is coated on the outer side of the main stent body 20, which is a so-called covered stent. Of course, a stent that does not cover the inner cover 60 or the outer cover 65 or a stent that covers only one cover may be used.

Referring also to the development view of FIG. 2, the stent main body 20 is formed by bending the linear frame 31 in a zigzag shape so as to form peaks 35 and valleys 37, and connecting both ends thereof. It has a plurality of strut portions 30 that are annular. Then, a plurality of these strut portions 30 are connected in the axial direction of the stent 10 via the bridge portion 40, so that the stent main body 20 is configured.

As the strut portion, not only the structure formed into an annular shape by bending both ends in a zigzag shape and connecting both ends, but a plurality of frame-like members bent in a predetermined shape are connected in a line in the circumferential direction of the stent. The structure may be formed in a ring shape.

Further, the V-shaped projecting portion 32 (the portion surrounded by the chain double-dashed line in FIG. 3) formed by bending the adjacent frames 31 and 31 into a V-shape of the strut portion 30 is a circumferential direction of each strut portion 30. It is preferable to provide 8 to 24 pieces, and more preferably 12 to 16 pieces.

In the following description, a protruding portion of the strut portion 30 that is bent and protruded toward one end side in the axial direction of the stent 10 (meaning the left side in the drawings in FIGS. 2 and 3, hereinafter, also simply referred to as “one end side”). Is the mountain portion 35. Further, a trough portion is a trough portion that is a protrusion portion that is bent and protruded to the other axial end side of the stent 10 (which means the right side in the drawings in FIGS. 2 and 3, hereinafter, simply referred to as “the other end side”). 37. In the following description, "one end" and "the other end" in the frame 41, the binding portion 50, the first bent portion 51, the second bent portion 53, and the like of the binding portion 50, which will be described later, respectively refer to the stent. It means an end portion on one end side in the axial direction and an end portion on the other end side in the axial direction.

As shown in FIG. 2, the mountain portion 35 of the strut portion 30, which is located at the head on one end side of the stent 10, is provided with a predetermined number (every two here) of ring-shaped pull-out portions 39. Has been. A loop-shaped pull-out wire 25 (see FIG. 1) is inserted through the plurality of pull-out portions 39, and as shown in FIG. 5, the pull-out wire 25 is grasped and pulled by the forceps 5 or the like. Thus, the stent 10 can be pulled out from the body. In addition, in FIG. 5, only the main stent body 20 is shown for convenience. Further, the pull-out portion 39 may be provided on all of the mountain portions 35 of the strut portion 30 located at the head on the one end side of the stent 10.

The stent 10 is accommodated in a medical tube (not shown) such as a catheter or a sheath in a reduced diameter state, and is pushed out from the distal end side of the medical tube into the body. In this case, the stent 10 is accommodated with the other end side provided with the troughs 37 facing the extrusion direction, and inserted into the body from the other end side. When recovering the stent 10 from the inside of the body, the stent 10 is pulled out from the one end side facing the mountain portion 35 and recovered.

That is, the "other end side of the stent" in the present invention is an end portion on the insertion direction side when the stent is inserted into the body, and the "one end side of the stent" is the extraction direction side when the stent is recovered from the body. It will be the end.

In addition, as shown in FIGS. 2 and 3, a plurality of mountain portions 35 of each strut portion 30 except for the strut portion 30 having the pull-out portion 39 located at the head on one end side of the stent 10 are formed by the bridge portion 40. They are bundled one by one (here, four) and connected to the troughs 37 of the strut portions 30 adjacent to one end of the stent. Further, except for the strut portion 30 having the pull-out portion 39 located at the head on one end side of the stent 10, all the peak portions 35 of each strut portion 30 are connected to the bridge portion 40, and the trough portion 37 of each strut portion 30 is , Which are not connected to the bridge portion 40.

The bridge portion 40 has a binding portion 50 that is bundled into one on the way toward the one end side of the stent 10, and the binding portion 50 is of the strut portion 30 adjacent to one end side of the stent 10. It is connected to the valley portion 37.

As shown in FIGS. 2 and 3, the bridge portion 40 of this embodiment has four frames 41, and the other end of each frame 41 is in the circumferential direction of the stent 10 of each strut portion 30. It is connected to each of the four adjacent mountain portions 35. In addition, in this embodiment, four mountain portions 35 of the strut portion 30 are bundled by the bridge portion 40, but the number of mountain portions 35 of the strut portion 30 bundled by the bridge portion 40 is not particularly limited. .. Further, the bridge portions 40 are preferably provided in the circumferential direction of each strut portion 30 in an amount of 3 to 6, and more preferably in an amount of 3 to 4.

Then, these four frames 41 are bundled into one to form a binding portion 50 by connecting one end of each frame 41 to each other on the way to the one end side of the stent 10, One end of the binding portion 50 is connected to the valley portion 37 of the strut portion 30 adjacent to the one end side of the stent 10. It should be noted that one end of the binding portion 50 may be connected to the mountain portion 35 of the strut portion 30 adjacent to the one end side of the stent 10. In addition, a portion in which the plurality of frames 41 are bundled so as to be one is referred to as a binding portion 45 in the following description.

The binding portion 50 in this embodiment has a first bent portion 51 that is bent in one circumferential direction R1 side of the stent 10 and a second bent portion 53 that is bent in the other circumferential direction R2 of the stent 10. All the apex portions 52 and 54 of the bent portions 51 and 53 are configured to face the other end side of the stent 10.

The binding portion 50 is bundled in the binding portion 45, and one frame 41 extending from the binding portion 45 toward the one end side of the stent is formed so as to form the first bent portion 51 and the second bent portion 53. It is configured by being bent appropriately. In general, the binding portion 50 of this embodiment has a shape in which both apexes of the two bent portions that are bent so as to form a substantially S shape are bent toward the other end side of the stent 10. Has become. Hereinafter, the shape of the binding portion 50 will be described in detail.

In the present invention, the "top" of each bent portion is a folded portion of the bent portion, and means the most protruding portion in the circumferential direction of the stent when viewed as the entire bent portion (Fig. 3, 8 and 10), and when there are a plurality of folded-back portions for each bent portion, it means the portion of each folded-back portion that projects most in the circumferential direction of the stent (see FIG. 12). Further, in the present invention, the fact that the top of the bent portion faces the other end means that both side portions of the bent portion facing the top of the bent portion are inclined toward the other end of the stent as a whole.

As shown in FIGS. 2 and 3, in the first bent portion 51 in this embodiment, both side portions 51a and 51b toward the top portion 52 are inclined toward the other end side with respect to the circumferential direction, and the first bent portion 51 is viewed as the entire bent portion. The direction of the top portion 52 when facing is toward the other end side. Note that one end 51c of the first bent portion 51 is connected to the binding portion 45.

On the other hand, in the second bent portion 53, both side portions 53a and 53b toward the top portion 54 are inclined toward the other end side with respect to the circumferential direction, and the direction of the top portion 54 when viewed as the entire bent portion is toward the other end side. It is facing. In addition, one end 53 c of the second bent portion 53 is connected to the valley portion 37 of the strut portion 30 adjacent to one end of the stent 10.

Further, an end of the one side portion 51a of the first bent portion 51 and an end of the other side portion 53b of the second bent portion 53 are bent in a mountain shape toward one end side of the stent 10 in a mountain-shaped bent portion. Although connected to each other via 56, the angle of the mountain-shaped bent portion 56 (both sides of the mountain-shaped bent portion 56, that is, the one side portion 51 a of the first bent portion 51 and the second bent portion 53). The angle formed by the other side portion 53b) is an obtuse angle. Further, in this embodiment, both ends in the axial direction of the binding portion 50, here, the other end 51c of the first bent portion 51 and the one end 53c of the second bent portion 53 are as shown in FIGS. 2 and 3. The positions are substantially aligned with each other in the circumferential direction of the stent 10.

The bundling portion is not limited to the above shape, and may have a shape as shown in FIGS. 8, 10, and 12 (these will be described later). That is, the binding portion may have at least two bending portions that bend in one circumferential direction and the other circumferential direction of the stent, and may have three or more bending portions. Further, the binding portion may be substantially Z-shaped or the like, and the tops of both of the two bent portions may be bent toward the other end of the stent. However, also in this case, it is necessary that all the apexes of each bent portion are configured to face the other end side of the stent.

Further, as described above, by connecting the plurality of strut portions 30 via the bridge portion 40, the strut portions 30 and 30 adjacent to each other in the stent axial direction and the bridge portions 40 and 40 adjacent to each other in the stent circumferential direction. A plurality of spaces S surrounded by (see FIGS. 2 and 3) are formed in the main stent body 20. Then, the first bent portion 51 and the second bent portion 53 of the binding portion 50 are arranged so as to enter the space S (see FIGS. 2 and 3).

The stent body 20 in this embodiment is formed by processing a metal cylinder by laser processing, etching, or the like to form a plurality of strut portions and bridge portions. However, for example, a metal plate may be processed to provide a plurality of struts and bridges each having a zigzag shape or a frame-like body, and the metal plate may be bent into a cylindrical shape to form the main stent body.

Further, the stent body 20 is a self-expanding type in which the diameter of the stent body 20 is normally expanded, but the balloon is expanded by expanding the balloon placed inside the stent by attaching it to a balloon catheter or the like. A diameter expansion type may be used.

The material of the stent body 20 is not particularly limited, but for example, stainless steel, Ta, Ti, Pt, Au, W, etc., Ni—Ti alloy, Co—Cr alloy, Co—Cr—Ni alloy, Cu. Shape memory alloys such as -Zn-X (X=Al, Fe, etc.) alloys, Ni-Ti-X (X=Fe, Cu, V, Co, etc.) alloys are preferable. In addition, at a predetermined position of the main stent body 20, for example, Pt, Ti, Pd, Rh, Au, W, Ag, Bi, Ta and alloys thereof, synthetic resin containing powder such as BaSO ₄ , Bi, W, An X-ray opaque X-ray marker made of stainless steel or the like may be provided.

Further, as described above, the inner cover 60 is coated on the inner side of the stent body 20 and the outer cover 65 is coated on the outer side thereof. The plurality of frames 31, the plurality of frames 41 of the bridge portion 40, and the frame 41 of the bundling portion 50 are closed. The inner cover 60 and the outer cover 65 are made of, for example, polyurethane, silicone, natural rubber, nylon elastomer, polyether block amide, polyethylene, polyvinyl chloride, vinyl acetate, and also polytetrafluoroethylene (PTFE), par. Fluoroalkoxy resin (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE) and other fluorine-based resins, polybutadiene and other olefin-based rubbers, styrene-based resins It is preferably formed of an elastomer or the like.

In addition, in the said embodiment, "each strut part except the strut part located at the head of the said one end side" in this invention refers to all strut parts 30 other than the strut part 30 which has the pull-out part 39. In addition, the "each strut portion" in the present invention refers to all strut portions 30 including the strut portion 30 having the pull-out portion 39, and the "struts adjacent to the one end side" in the present invention. “Part” refers to a predetermined strut portion 30 adjacent to a predetermined strut portion 30 (for example, in FIG. 2, the strut portion 30 at the right end (the other end in the axial direction) of the paper surface). On the other hand, the second strut portion 30 located next to it from the right end of the paper surface). This also applies to the embodiments described later.

Next, an example of a method of using the stent 10 of the present invention having the above structure will be described. Note that this usage method is an example, and is not particularly limited.

As shown in FIG. 6, a papilla 2 is provided below the duodenum 1, and a bile duct 3 and a pancreatic duct 4 branch from the papilla 2 and extend. Further, bile generated by the liver (not shown) flows in the bile duct 3, passes through the papilla 2, and is supplied to the duodenum 1. Here, a procedure for placing the stent 10 in the bile duct 3 through the papilla 2 will be described.

In addition to the bile duct 3, the stent 10 of the present invention can be placed in the pancreatic duct 4, tubular organs such as the esophagus, trachea, large intestine, and blood vessels, and the body such as a body cavity, and the application site is not particularly limited.

First, the diameter of the stent 10 is reduced and accommodated in a medical tube (not shown) such as a catheter or a sheath. At this time, one side of the stent having the strut portion 30 having the pull-out portion 39 is directed toward the proximal side, and the other side of the stent is directed toward the distal end side of the tube in a state where the diameter of the stent 10 is reduced in the medical tube. Accommodate.

In this state, a guide wire is inserted into the bile duct 3 through a lumen of an endoscope (not shown) by a well-known method, and then a medical tube is inserted through the guide wire. Inserted into the bile duct 3. When the tip of the medical tube reaches the predetermined position of the bile duct 3, the insertion of the medical tube is completed. Thereafter, by releasing the stent 10 from the tube tip via a pusher or the like, the diameter of the stent 10 is expanded, and the other end side of the stent is placed in the bile duct 3 as shown in FIG. The stent 10 is placed so that it is slightly projected from the teat 2.

The stent 10 thus placed in the bile duct 3 maintains the expanded diameter of the bile duct 3, but the lumen of the stent 10 is occluded due to bodily fluid such as bile or proliferation of cancer cells, or When the treatment is completed, it may be desired to retrieve the stent 10 from the body.

In this case, as shown in FIG. 7, for example, the forceps 5 is inserted into the duodenum 1 through a lumen of an endoscope (not shown), and the forceps 5 pulls out a loop-shaped pull-out wire 25 provided on one end side of the stent. Is grasped and the forceps 5 is pulled toward the operator's hand side as shown in FIG. The loop-shaped snare may be hooked on one end side of the stent and the stent may be pulled through the snare, and the means for pulling the stent is not particularly limited.

At this time, a plurality of mountain portions 35 of each strut portion 30 except the strut portion 30 having the pull-out portion 39 located at the head on one end side of the stent 10 are bundled by a plurality of bridge portions 40 and adjacent to one end side of the stent. All the mountain portions 35 of each strut portion 30 are connected to the bridge portion 40, except for the strut portion 30 that is connected to the trough portion 37 of the strut portion 30 and that has the pull-out portion 39 located at the beginning on one end side of the stent 10. As described above, the strut having the pull-out portion 39 located at the leading end on the one end side of the stent 10 through the strut portion 30 located at the leading end on the one end side of the stent when pulled from the one end side of the stent as described above. All the peak portions 35 of each strut portion 30 except the portion 30 are pulled via the bridge portion 40 that bundles them in plural.

As a result, as shown in FIG. 5, the ridges 35 of each strut portion 30 are converged, the diameter of the stent 10 is likely to be reduced, and a strut having a withdrawal portion 39 located at the leading end on one end side of the stent 10 is provided. Since all the mountain portions 35 of each strut portion 30 except the portion 30 are connected to the bridge portion 40, the protrusion portion protruding to the one end side of the stent 10 does not exist independently, and each strut portion It is possible to prevent the plurality of mountain portions 35 of 30 from being caught on the inner wall of the body such as the bile duct 3 or the like.

At the same time, the binding portion 50 of the bridge portion 40 that connects the adjacent strut portions 30, 30 includes the first bent portion 51 that bends in one circumferential direction R1 of the stent 10 and the other circumferential direction R2 of the stent 10. Since each of the bent portions 51, 53 has a second bent portion 53 that bends to the top and the top portions 52, 54 of the bent portions 51, 53 are configured to face the other end side of the stent 10, The tops 52 and 54 can be made less likely to be caught on the inner wall of the body such as the bile duct 3.

As described above, in the stent 10, the plurality of peaks 35 of each strut portion 30 and the tops 52 and 54 of the respective bent portions 51 and 53 of the bundling portion 50 are less likely to be caught on the inner wall of the body. Therefore, the stent 10 can be smoothly extracted from the body. In the case of this embodiment, the stent 10 extracted from the bile duct 3 can be recovered from the body through the lumen of an endoscope (not shown).

The binding portion 50 of the stent 10 has two bent portions 51 and 53 that bend in one circumferential direction R1 and the other circumferential direction R2 of the stent 10, so that the binding portion 50 is secured long. As a result, it is possible to enhance the flexibility of the binding portion 50 and make it difficult to kink the bridge portion 40. Therefore, even when the tubular organ or the like is bent, the stent 10 can be appropriately bent in accordance with the bent tubular organ, and the stent 10 can be placed while holding its lumen. Even after the stent 10 is compressed and bent due to proliferation of cancer cells or the like after the placement, the bridge portion 40 is less likely to be kinked and the narrowing of the stent lumen can be prevented.

8 and 9 show a second embodiment of a stent according to the present invention. It should be noted that substantially the same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the stent 10A of the second embodiment, the shape of the binding portion 50A of the bridge portion 40 is different from that of the above embodiment.

As shown in FIG. 8, the binding portion 50A of the stent 10A includes a first bent portion 51A that is bent in one circumferential direction R1 side of the stent 10A and a second bent portion that is bent in another circumferential direction R2 side of the stent 10A. The bent portion 51A and the bent portion 51A are both bent in a bow shape. The bent portions 51A and 53A are arranged at substantially aligned positions in the axial direction of the stent 10A. In addition, all the apex portions of the bent portion, that is, the apex portion 52 of the first bent portion 51A and the apex portion 54 of the second bent portion 53A are the same as the plurality of frames 41 in the binding portion 50A in the axial direction of the stent 10A. It is arranged closer to the other end of the stent 10A than the binding portion 45 that is bundled into a book.

As shown in FIG. 9, when the diameter of the stent 10A is reduced, the first bent portion 51A of the predetermined binding portion 50A and the first binding portion 50A of the other binding portion 50A adjacent to the binding portion 50A in the circumferential direction of the stent. The two bent portions 53A come close to each other.

And in this 2nd Embodiment, since each top part 52,54 of each bending part 51A, 53A is located in the other end side of the stent 10A rather than the said binding part 45, the length of the binding part 50A is long. The length can be secured longer, and the bridge portion 40 can be made more difficult to kink. In addition, a space in which the long first bent portion 51A and the second bent portion 53A of the binding portion 50A are surrounded by the strut portions 30 and 30 adjacent in the stent axial direction and the bridge portions 40 and 40 adjacent in the stent circumferential direction. Since it can be arranged so as to enter the S, the contact area of the bridge portion 40 with the inner wall of the body can be increased, a uniform expansion force can be transmitted to the inner wall, and the stent When an external force acts on 10A (for example, when it is placed in a tubular organ having a small inner diameter, the pressing force from its inner wall is large, or when the stent 10A is reduced in diameter to be housed in a medical tube). It is possible to suppress the depression of the covers 60 and 65 coated on the inside or outside of the stent body 20.

10 and 11 show a third embodiment of the stent according to the present invention. It should be noted that substantially the same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the stent 10B of the third embodiment, the shape of the binding portion 50B of the bridge portion 40 is different from that of the above embodiment.

As shown in FIG. 10, the binding portion 50B in the stent 10B includes a first bent portion 51B bent in one circumferential direction R1 side of the stent 10B and a second bent bent in another circumferential direction R2 side of the stent 10B. The bent portion 51A and the bent portion 51A are both bent in a bow shape. Further, the top portion 52 of the first bent portion 51B and the top portion 54 of the second bent portion 53B are displaced from each other in the axial direction of the stent 10B. Here, the first bent portion 51B is displaced from the second bent portion 53B so as to be on the other end side of the stent 10B. Then, among the tops 52, 54 of the respective bent portions 51B, 53B, the top portion 52 of the first bent portion 51B that is displaced to the other end side of the stent 10B from the top portion 54 of the second bent portion 53B is the stent 10B. In the axial direction of the above, it is arranged on the other end side of the stent 10B with respect to the binding portion 50B with respect to the binding portion 45 in which the plurality of frames 41 are bundled into one.

Then, in the third embodiment, when the diameter of the stent 10B is reduced, as shown in FIG. 11, in the space S surrounded by the strut portion 30 and the bridge portion 40, the first binding portion 50B of the predetermined binding portion 50B is formed. As the bent portion 51B enters, the second bent portion 53B of another binding portion 50B adjacent to the binding portion 50B in the stent circumferential direction also enters. At this time, since the top portion 52 of the first bent portion 51B is displaced from the top portion 54 of the second bent portion 53B toward the other end side of the stent 10B, the first bent portion 51B of the predetermined binding portion 50B is The second bent portion 53B of the other binding portion 50B adjacent to the circumferential direction is less likely to interfere with the second binding portion 53B, and the diameter of the stent 10B can be easily reduced. Further, the binding portion 50B can be secured long to make the bridge portion 40 less likely to kink, and the contact area of the bridge portion 40 with the inner wall of the body can be increased to provide a uniform expansion force on the inner wall. In addition to being able to transmit the above, when the external force acts on the stent 10B, it is possible to suppress the depression of the covers 60 and 65 coated inside or outside the stent body 20.

FIG. 12 shows a fourth embodiment of the stent according to the present invention. It should be noted that substantially the same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the stent 10C of the fourth embodiment, the shape of the binding portion 50C of the bridge portion 40 is different from that of the above embodiment.

As shown in FIG. 12, the binding portion 50C of the stent 10C includes a first bent portion 51C that is bent in one circumferential direction R1 side of the stent 10C and a second bent portion that is bent in another circumferential direction R2 side of the stent 10B. The first bent portion 51C is provided with two tops 52, 52, and the second bent portion 53C is also provided with two tops 54, 54. There is.

That is, the first bent portion 51C has a shape in which the two top portions 52, 52 are provided in parallel with each other through the recessed bent portion 57 and is bent in a substantially heart shape, and this is oblique with respect to the stent axis. It is located in. Similarly, the second bent portion 53C also has a shape in which the two top portions 54, 54 are provided in parallel with each other via the recessed bent portion 57, and is bent in a substantially heart shape. It is arranged diagonally. The number of tops provided on each bent portion may be three or more, and is not particularly limited.

Further, in the fourth embodiment, since the plurality of top portions 52 and the plurality of top portions 54 are provided in each of the bent portions 51C and 53C, the binding portion 50C is secured longer and the bridge portion 40 is less likely to kink. In addition, the contact area of the bridge portion 40 with the inner wall of the body can be increased to transmit a uniform expansion force to the inner wall, and further, when an external force acts on the stent 10C, the stent body 20 It is possible to suppress the depression of the covers 60 and 65 coated on the inner side or the outer side.

The present invention is not limited to the above-described embodiment, and various modified embodiments are possible within the scope of the gist of the present invention, and such an embodiment is also included in the scope of the present invention. ..

10, 10A, 10B, 10C Stent 20 Stent body 30 Strut portion 35 Crest 37 Valley 40 Bridge portion 45 Bundling portions 50, 50A, 50B, 50C Bundling portions 51, 51A, 51B, 51C First bent portion 52 Top portion 53, 53A, 53B, 53C Second bent portion 54 Top 60 Inner cover 65 Outer cover

Claims (4)

It is bent in a zigzag shape and its both ends are connected to form an annular shape, or a frame-like body that is bent into a predetermined shape is formed in an annular shape by connecting a plurality of them side by side in the circumferential direction. A strut portion and a bridge portion connecting a plurality of these strut portions in the axial direction,
In each strut portion, when the protruding portion protruding to one end side of the stent is a mountain portion, and the protruding portion protruding to the other end side is a valley portion,
The crests of each strut part except the strut part located at the head of the one end side are all connected to the bridge part, and a plurality of the strut parts are bundled by the bridge part and are adjacent to the one end side. Part, which is connected to the valley part or the mountain part, and the valley part of each strut part has one that is not connected to the bridge part,
The bridge part has a binding part that is bundled into one on the way to the one end side, and the binding part is the trough part or the mountain part of the strut part adjacent to the one end side. Is connected to
The binding portion has at least two bending portions that bend in one circumferential direction and the other circumferential direction of the stent, and all the tops of the respective bending portions are configured to face the other end side. A stent which is characterized by being. The stent according to claim 1, wherein all the apex portions of the bent portion are arranged on the other end side of a portion of the binding portion that is bundled into one in the axial direction of the stent. The top of the bent portion that bends in one circumferential direction of the stent, and the top of the bent portion that bends in the other circumferential direction of the stent are displaced from each other in the axial direction of the stent. The top part which is displaced to the other end side among the top parts is arranged on the other end side in the axial direction of the stent rather than the part of the binding part which is bundled into one. Stent. The apex of the bent portion that bends in one circumferential direction of the stent, and the apex of the bent portion that bends in the other circumferential direction of the stent are provided in plurality. The stent according to one.

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