JP6985526B2 - Stents and medical devices - Google Patents

Description

The present invention relates to stents applied to tubular organs in the body, such as gastrointestinal tracts and blood vessels, and medical devices such as covered stents or stent grafts equipped with such stents.

A stent applied (indwelling) to the gastrointestinal tract (gastrointestinal stent) is used to push open the lumen of the gastrointestinal tract narrowed by a tumor. In addition to the gastrointestinal tract, stents are also used for other tubular organs in the body such as blood vessels. Stents applied to such tubular organs in the body generally have a network structure using one or more wires (see, for example, Patent Document 1).

Special Table 2009-501049 Gazette

By the way, in such a stent, it is generally required to suppress the misalignment at the time of treatment (when the stent is placed in the above-mentioned tubular organ in the body). It is desirable to provide stents capable of suppressing misalignment during treatment and medical devices equipped with such stents.

The stent according to the embodiment of the present invention is formed by using the same wire rod, and includes a mesh-like structure having a tubular structure extending along the axial direction of the stent. In this mesh-like structure, a plurality of unit structures configured by using the same wire rod are arranged side by side in each of both end regions and non-end regions along the axial direction. Further, the unit structure in at least one end region of both end regions is compared with the length in the first axial direction, which is the length of the unit structure in the non-end region along the axial direction. The length in the second axial direction, which is the length along the axial direction, is relatively short. Further, the braided pattern of the wire rod in the mesh-like structure is different from each other in the non-end region and at least one end region, and the braid pattern is added in the non-end region. As a result, the arrangement density of the wire rod in the braided pattern of the non-end region is higher than the arrangement density of the wire rod in the braided pattern of at least one end region.

The medical device according to the embodiment of the present invention includes a tubular member and at least one stent according to the embodiment of the present invention disposed on at least a part of the tubular member. Is.

In the stent and medical device according to the embodiment of the present invention, the second axis in at least one end region of both end regions is compared with the first axial length in the non-end region. The directional length is relatively short (the first axial length> the second axial length). Thereby, for example, the stent is inserted into a predetermined delivery sheath in a reduced diameter state, the delivery sheath is carried to the vicinity of the affected part (the site to be treated) in the tubular organ, and then the stent is delivered to the delivery sheath. When it is deployed from the inside and the diameter is expanded, it becomes as follows. That is, since the length in the second axial direction is relatively short in at least one end region, the unit structure for one row along the axial direction protrudes from the inside of the delivery sheath to the outside. The time is relatively short. As a result, for example, in the at least one end region, as in the non-end region, the end region of the stent becomes earlier (as compared with the case where the unit structure has the first axial length). It is easy to expand the diameter (with a short protrusion length). Further, the braided pattern of the wire rod in the mesh-like structure is different between the non-end region and the at least one end region, so that the result is as follows. That is, for example, by making the braided pattern in the at least one end region a pattern that is relatively easy to expand in diameter as compared with the braided pattern in the non-end region, the stent can be obtained from within the delivery sheath. When deployed, the diameter can be expanded earlier. As a result, the displacement of the stent during treatment is further suppressed.

In the stent and medical device according to the embodiment of the present invention, in the at least one end region, the number of rows arranged side by side along the axial direction of the unit structure having the second axial length is determined. There may be more than one. In this case, since there are a plurality of rows of unit structures having the second axial length in at least one end region, when this stent is deployed from within the delivery sheath, the following Will be. That is, since the diameter of at least one end region as a whole tends to gradually (continuously) expand, the end region of this stent tends to expand in diameter at an earlier stage, and as a result, during treatment. The displacement of the stent is further suppressed.

Further, in the stent and the medical device according to the embodiment of the present invention, the first circumferential length, which is the length along the circumferential direction orthogonal to the axial direction, in the unit structure of the non-end region, and the above. In the unit structure of at least one end region, the length in the second circumferential direction, which is the length along the circumferential direction, may be substantially the same as each other.

Further, in the stent and the medical device according to the embodiment of the present invention, the second axial length is relatively shorter than the first axial length in both end regions, and the second axial length is relatively shorter. At least one of the number of columns arranged side by side along the axial direction of the unit structure having the second axial length and the magnitude of the second axial length is the end region of both of the above. One of the end regions and the other end region may be different from each other (may be asymmetrical to each other). In this case, the characteristics of the stent (deployment profile, etc.) can be made different between the one end region and the other end region. Therefore, for example, depending on the use and usage of the stent. , The characteristics can be selectively set. As a result, the convenience of using the stent is improved.

According to the stent and the medical device according to the embodiment of the present invention, the length in the second axial direction is relatively shorter than the length in the first axial direction. .. That is, for example, when the stent is expanded from the reduced diameter state in a predetermined delivery sheath and expanded in diameter, the end region of the stent is likely to expand in diameter at an early stage. Therefore, when the stent is placed in the affected area (site to be treated), the stent is quickly fixed to the affected area, and as a result, it is possible to suppress the displacement of the stent during treatment. ..

It is a schematic perspective view which shows the schematic structural example of the stent which concerns on one Embodiment of this invention. It is a schematic development view which shows the detailed structure example of the main part in the stent shown in FIG. It is a schematic development figure which shows the structural example of the main part in the stent which concerns on a comparative example. It is a schematic development view which shows the structural example of the main part in the stent which concerns on the modification 1. It is a schematic development view which shows the structural example of the main part in the stent which concerns on the modification 2. It is a schematic development view which shows the structural example of the main part in the stent which concerns on the modification 3. It is a schematic development view which shows the structural example of the main part in the stent which concerns on the modification 4. It is a schematic perspective view which shows the schematic structure example of the medical device which concerns on application example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The explanation will be given in the following order.
1. 1. Embodiment (Example when (L2 <L1) is satisfied in a plurality of rows of both end regions)
2. 2. Modification example Modification 1 (example when (L2 <L1) is satisfied in one row of both end regions)
Modification 2 (Example in which the number of columns and the size of L2 are asymmetric between both end regions)
Deformation example 3 (Example when the braided pattern of the wire rod differs between the non-end region and the end region)
Modification 4 (Example in which (L2 <L1) is satisfied only in one end region)
3. 3. Application example (example when the stent of the embodiment and each modification is applied to a medical device)
4. Other variants

<1. Embodiment>
[Rough configuration]
FIG. 1 is a schematic perspective view showing a schematic configuration example of a stent (stent 11) according to an embodiment of the present invention. The stent 11 is, for example, an instrument applied to the gastrointestinal tract as a tubular organ in the body, and is used to push open the lumen of the gastrointestinal tract narrowed by a tumor, as will be described later. Specifically, the stent 11 is placed in a site to be treated (for example, in the digestive tract such as the large intestine). The stent 11 corresponds to a specific example of the "stent" in the present invention.

As shown in FIG. 1, the stent 11 has a tubular (cylindrical) structure extending along the axial direction Z (Z-axis direction). Further, the stent 11 has both end regions (end regions Aea and Aeb) and non-end regions Am (intermediate regions located between both end regions) along the axial direction Z. Has (see Figure 1). The length of the entire stent 11 along the axial direction Z is, for example, about 3 to 20 cm, and the lengths of the end regions Aea and Aeb are, for example, about 3 to 40 mm, respectively. On the other hand, the outer diameter of the stent 11 when expanded is, for example, about 10 to 50 mm.

In the example shown in FIG. 1, the stent 11 is configured by using one kind of wire rod W1 (wire), and has a tubular structure as described above. Specifically, in the present embodiment, this tubular structure is configured by a mesh-like structure, and such a tubular mesh-like structure forms a wire rod W1 in a predetermined pattern (a mesh pattern described later). Each is formed by knitting. The details of the mesh structure (braided pattern of the wire rod W1) and the like in the stent 11 will be described later (FIG. 2).

Here, as the material of such a wire rod W1, a metal wire rod is preferable, and a shape memory alloy, which is imparted with a shape memory effect and superelasticity by heat treatment, is particularly preferably adopted. However, depending on the application, stainless steel, tantalum (Ta), titanium (Ti), platinum (Pt), gold (Au), tungsten (W) or the like may be used as the material of the wire rod W1. Examples of the shape memory alloy described above include nickel (Ni) -Ti alloy, copper (Cu) -zinc (Zn) -X (X = aluminum (Al), iron (Fe), etc.) alloy, and Ni-Ti-X. (X = Fe, Cu, vanadium (V), cobalt (Co), etc.) Alloys and the like are preferably used. As such a wire rod W1, for example, a synthetic resin or the like may be used. Further, a metal wire whose surface is coated with Au, Pt, etc. by means such as plating, or a composite wire, which is a core material made of a radiation-impermeable material such as Au, Pt, covered with an alloy, is used. It may be used as W1.

[Detailed configuration]
Subsequently, with reference to FIG. 2, a detailed configuration example of the stent 11 shown in FIG. 1 (configuration example of the above-mentioned network structure and the like) will be described. FIG. 2 is a schematic development view of a detailed configuration example of a main part (near the above-mentioned end regions Aea and Aeb) in the stent 11, and is shown in FIG. 1 in the axial direction Z and the circumferential direction R. It is shown along each direction of.

First, as shown in FIG. 2, the stent 11 is configured by using one kind of network structure 111. That is, the stent 11 is composed of a mesh-like structure 111 formed by using the above-mentioned wire rod W1. The mesh-like structure 111 constitutes the above-mentioned tubular structure and extends along the axial direction Z of the stent 11 (over the entire length). As the wire diameter of such a wire rod W1, for example, about 0.18 mm can be mentioned.

As shown in FIG. 2, the mesh-like structure 111 is formed by intersecting a wire rod W1 having a corrugated shape (zigzag shape) including a straight line portion s1 and a bent portion b1 at the straight line portion s1. .. Therefore, in this mesh-like structure 111, an intersection (wire intersection) is formed, which is a portion where the straight portions s1 of the wire W1 intersect with each other.

Further, in the mesh-like structure 111, as shown in FIG. 2, a connecting portion C11 (engagement portion) is formed in which the wire rods W1 are connected (engaged) with each other at the bent portion b1. That is, in the mesh-like structure 111, a mesh pattern formed by advancing a wire rod W1 having a corrugated shape including a straight portion s1 and a bent portion b1 along the circumferential direction R is connected along the axial direction Z. It is composed of.

Specifically, the mesh pattern of each row (one row) is formed by orbiting the wire rod W1 twice along the circumferential direction R while forming the above-mentioned corrugated shape. Specifically, in the loop of the first lap and the loop of the second lap, the phase of the waveform shape is deviated from each other by half pitch (1/2 pitch) along the circumferential direction R in the mesh pattern of each row. It is in a state of being. As a result, in the mesh pattern of each row, the above-mentioned intersections are arranged side by side along the circumferential direction R. At such an intersection, the loop on the first lap and the loop on the second lap are arranged so as to alternately move up and down.

Further, although omitted in FIG. 2, the wire rod W1 is orbited twice along the circumferential direction R to form a mesh pattern (an integer of N: 1 or more) for one row (Nth row). After that, the end of the loop on the second lap is as follows. That is, it proceeds along the axial direction Z to the formation position of the mesh pattern in the next column ((N + 1) th column), and the mesh pattern is formed in the same manner as described above. The bent portion of the (N + 1) row is knitted so as to be connected to the bent portion of the Nth row.

In this way, the mesh-like structure 111 in which the mesh pattern is provided along the axial direction Z is formed, and the stent 11 is formed.

As shown in FIG. 2, such a network structure 111 is formed by a plurality of unit structures (unit structures U1 and U2) arranged two-dimensionally side by side along each of the axial direction Z and the circumferential direction R. It is configured. Specifically, in the network structure 111, a plurality of unit structures U1 are two-dimensionally arranged in the above-mentioned non-end region Am (intermediate region), and in the above-mentioned end regions Aea and Aeb, respectively. , A plurality of unit structures U2 are arranged two-dimensionally (see FIG. 2). In other words, each row of the mesh pattern constituting the end regions Aea and Aeb is formed by arranging a plurality of unit structures U2 side by side along the circumferential direction R. On the other hand, each row of the mesh pattern constituting the non-end region Am is formed by arranging a plurality of unit structures U1 side by side along the circumferential direction R.

In the example shown in FIG. 2, each unit structure U1 has an axial direction Z as a major axis direction and a circumferential direction R as a minor axis direction, and has two bent portions b1 and two wire rod intersections (the above-mentioned wire rods W1 and each other). It has a substantially rhombic shape with the apex of the intersection). Therefore, in this example, the length (axial length L1) along the axial direction Z in each unit structure U1 is the wave height of each wire rod W1 in the non-end region Am (the length of the axial direction Z in the above-mentioned waveform shape). (See Fig. 2).

In the example shown in FIG. 2, each unit structure U2 has a substantially rhombic shape with the axial direction Z and the circumferential direction R as the axial directions and the two bent portions b1 and the two wire rod intersections as the vertices. There is. Therefore, in this example, the length (axial length L2) along the axial direction Z in each unit structure U2 coincides with the wave height of each wire rod W1 in the end regions Aea and Aeb (see FIG. 2).

Further, particularly in the present embodiment, as shown in FIG. 2, in both end regions Aea and Aeb, unit structures U2 having such an axial length L2 are arranged in a plurality of rows along the axial direction Z. They are arranged side by side. That is, each of these end regions Aea and Aeb has a plurality of columns (two columns each in this example) along the axial direction Z in the unit structure U2 (see FIG. 2).

The above-mentioned axial length L1 corresponds to a specific example of the "first axial length" in the present invention, and the axial length L2 corresponds to a specific example of the "second axial length" in the present invention. is doing.

Here, in the network structure 111 in the stent 11 of the present embodiment, the axial length L1 of each unit structure U1 in such a non-end region Am and each unit structure U2 in the end regions Aea and Aeb The magnitude relationship with the axial length L2 is as follows. That is, as shown in FIG. 2, the axial length L2 in the end regions Aea and Aeb is relatively shorter than the axial length L1 in the non-end region Am. That is, the magnitude relationship (axial length L2 <axial length L1) is satisfied.

In other words, in this stent 11, the crest value is formed so as to be different between the mesh pattern constituting the end region Aea and Aeb and the mesh pattern constituting the non-end region Am (see FIG. 2). As shown in FIG. 2, the crest value in the mesh pattern constituting the non-end region Am is larger than the crest value in the mesh pattern constituting the end regions Aea and Aeb.

The axial length L1 is, for example, about 8 to 24 mm, and the axial length L2 is, for example, about 1 to 18 mm. The numerical range of the ratio of the axial length L2 to the axial length L1 ((L2 / L1) × 100) is preferably, for example, 12.5 to 75%, more preferably 30 to 60%. be.

[Action / Effect]
(A. Basic operation)
When treating a tumor near the gastrointestinal tract in a patient, the stent 11 is placed in the site to be treated (for example, in the gastrointestinal tract such as the large intestine) to push the lumen of the gastrointestinal tract narrowed by the tumor. It will be possible to open it.

At this time, specifically, first, the stent 11 is inserted into a predetermined delivery sheath in a reduced diameter state, and the delivery sheath is inserted into the gastrointestinal tract to carry the stent 11 to the vicinity of the affected area. Then, the stent 11 is expanded from the inside of the delivery sheath and expanded in diameter, so that the stent 11 is placed in the affected area (the site to be treated).

(B. Action / effect on stent 11)
Next, the action and effect of the stent 11 will be described in detail with reference to FIGS. 3 in addition to FIGS. 1 and 2 in comparison with a comparative example.

(B-1. Comparative example)
FIG. 3 is a schematic development view of a configuration example of a main part (near the end regions Aea and Aeb) in the stent (stent 100) according to the comparative example, in the axial direction Z and the circumferential direction R. Represented along each direction.

As shown in FIG. 3, the stent 100 of this comparative example is composed of a network-like structure 101 formed by using the wire rod W1. In the mesh-like structure 101 of this comparative example, both end regions Aea and Aeb are also formed by a mesh pattern (see FIG. 2) constituting the non-end region Am in the mesh-like structure 111 of the present embodiment. In that respect, it is different from the mesh-like structure 111 of the present embodiment. That is, in the entire network structure 101, only one type of unit structure U1 is two-dimensionally arranged. Therefore, in the network structure 101, the axial length of the unit structure (unit structure U1) in these end regions Aea and Aeb and the axial length of the unit structure (unit structure U1) in the non-end region Am are different. , Both are L1 (see FIG. 3).

In the stent 100 of the comparative example having such a configuration, for example, as described above, the stent 100 is inserted into a predetermined delivery sheath in a reduced diameter state, and the delivery sheath is carried to the vicinity of the affected part in the digestive tract before delivery. When it is deployed from inside the sheath and the diameter is expanded, it becomes as follows.

That is, in this stent 100 (mesh structure 101), since the axial length L1 of each unit structure U1 in the end regions Aea and Aeb (and the non-end region Am) is long, the end region (end region). The protrusion length until the diameter of Aea or the end region Aeb) is expanded (returns to the original diameter) becomes long. Therefore, it takes time for the unit structure U1 for one row along the axial direction Z to project from the inside of the delivery sheath to the outside.

Here, in the stent 100 of this comparative example, as described above, the factors that require time for the unit structure U1 for one row along the axial direction Z to protrude outward (from inside the delivery sheath) are as follows. The problems (A) and (B) will be illustrated and specifically described. Here, for convenience of explanation, the first column and the second column will be described as an example, but the same can be said when the first column and the second column are generalized as the Nth column and the (N + 1) column.

(A) When the first row begins to protrude When the first row (endmost row) in the end region (end region Aea or end region Aeb) expands from the delivery sheath and expands in diameter. Even if the first row starts to protrude, a part of each unit structure U1 in the end region is housed in the delivery sheath. In such a state, the diameter of the first row in the end region cannot be sufficiently expanded.
(B) When the entire area of the first row protrudes and the second row is still stored The entire area of the first row in the end region protrudes from the inside of the delivery sheath to the outside, and the second row is still delivered. When stored in the sheath, it will be as follows. That is, in this case, the distal end in the first row expands in diameter and returns to the original diameter, while the proximal end in the first row has the same diameter as the distal end in the second row. (At the stage where the entire area of the first row protrudes, the diameter of the proximal end in the first row is the same as the inner diameter of the delivery sheath). This is because the proximal bending portion b1 in the first row and the distal bending portion b1 in the second row are connected (engaged) as described above. Then, in this case, the proximal end in the first row does not expand sufficiently, and the diameter of the first row expands diagonally (tapered state).

In this way, in the stent 100 of the comparative example, it takes time for the end region to sufficiently expand in diameter. Therefore, when the stent 100 is placed in the affected area (during treatment), the affected area is treated. It takes time for the stent 100 to be sufficiently fixed. As a result, in this comparative example, there is a possibility that the indwelling position of the stent 100 is displaced (positionally displaced).

In such a comparative example, it can be said that, for example, the following problem (C) may occur even after the stent 100 is placed.

(C) After placement of the stent 100 Generally, when a stent is placed in a stenosis to be treated, the stent is placed so as to straddle the stenosis. Specifically, for example, stents having a predetermined length (for example, 2 cm or more) are placed on both sides of the stenosis. Here, for example, when the placement position of the stent 100 is displaced due to sluggishness during placement, or when the position shift (migration) occurs after the stent 100 is placed, the following occurs. That is, if the delivery sheath is simply changed to the narrowed portion and a part of the first row is pushed by the tumor to reduce the diameter, the situation similar to the above problem (A) occurs, for example. If a part of the second row is pushed by the tumor and the diameter is reduced, the situation similar to the above problem (B) will occur.

Contrary to such a comparative example, when both the end regions Aea and Aeb and the non-end regions Am are configured using the unit structure U2 (when the axial length of the unit structure is both L2). May cause the following problems, for example. That is, in this case, as compared with the stent 11 of the present embodiment, the number of bending portions b1 and the number of connecting portions between the bending portions b1 are increased, so that the diameter reduction property of the stent is lowered and the delivery sheath is reduced. It can be said that the resistance when pulling out the stent from the stent may increase.

(B-2. Embodiment of this present)
On the other hand, in the stent 11 of the present embodiment, as shown in FIG. 2, as compared with the axial length L1 of each unit structure U1 in the non-end region Am, each unit structure U2 in the end regions Aea and Aeb Axial length L2 is relatively short (axial length L2 <axial length L1). As a result, for example, as described above, the stent 11 is inserted into a predetermined delivery sheath in a reduced diameter state, the delivery sheath is carried to the vicinity of the affected area in the digestive tract, and then the stent 11 is removed from the delivery sheath. When expanded and expanded in diameter, it becomes as follows.

That is, since the axial length L2 is relatively short in the end regions Aea and Aeb, the time until the unit structure U2 for one row along the axial direction Z projects from the inside of the delivery sheath to the outside. (The length of the stent 11 in the protruding portion) is relatively shorter than in the case of the above comparative example (when the end regions Aea and Aeb are configured by using the unit structure U1). As a result, in the present embodiment, for example, as in the above comparative example, in the end regions Aea and Aeb, the unit structure (unit structure U1) has an axial length L1 (> axial direction) as in the non-end region Am. Compared with the case of having a length L2) (see FIG. 3), the result is as follows. That is, in the present embodiment, the end region (end region Aea or end region Aeb) of the stent 11 tends to expand in diameter at an early stage (with a short protrusion length) as compared with the above comparative example.

In this way, in the present embodiment, for example, when the stent 11 is expanded from the reduced diameter state in the delivery sheath and expanded in diameter, the end region of the stent 11 is likely to expand in diameter at an early stage (. (It becomes easier to return to the original diameter at an early stage) As a result, it becomes as follows. That is, since the end region of the stent 11 tends to expand in diameter at an early stage, when the stent 11 is placed in the affected area, the stent 11 is quickly fixed to the affected area. Specifically, since the axial length L2 of the first row (endmost row) in the end region is relatively short, for example, the possibility that the above-mentioned problem (A) may occur is avoided. As a result, as described above, the stent 11 is rapidly fixed to the affected area. Therefore, in the present embodiment, it is possible to suppress the displacement of the stent 11 during treatment as compared with the above comparative example.

Further, in the present embodiment, as described above, the end region of the stent 11 tends to expand in diameter at an early stage (it becomes easy to return to the original diameter at an early stage), so that the following effects can be obtained, for example. ..

That is, first, the narrowed portion to be treated can be hooked and indwelled in the enlarged diameter portion in the end region, and it becomes possible to facilitate more accurate indwelling.

Further, if the diameter cannot be increased with a short protrusion length, for example, the following risks occur, but in the present embodiment, such a risk can be avoided. That is, if the diameter cannot be expanded with a short protrusion length, for example, if the diameter is displaced from the stenotic part (such as when an indwelling error or migration occurs), or if a doctor makes a mistake in selecting the stent size, the protrusion length becomes short. In some cases, such as, the end region of the stent may not expand in diameter.

Further, in the present embodiment, as described above, since the axial length L2 is relatively short in the end regions Aea and Aeb, the above-mentioned problem (C) arises unlike the comparative example. It is possible to avoid fear and avoid it. In particular, in the stent 11 of the present embodiment, the axial length L2 is relatively shorter than the axial length L1 in both end regions Aea and Aeb, so that this problem (C) is solved. It can be said that being able to avoid the possibility of occurrence has a great advantage.

Further, in the present embodiment, in the end regions Aea and Aeb, the number of rows along the axial direction Z of the unit structure U2 having the axial length L2 is a plurality (two rows each). (See Fig. 2), as follows. That is, since there are a plurality of rows of unit structures U2 having an axial length L2 in the end regions Aea and Aeb, when the stent 11 is deployed from within the delivery sheath, the end region (end region Aea or Aea or The end region Aeb) as a whole tends to gradually (continuously) increase in diameter.

Specifically, for example, when the entire area of the first row (endmost row) in the end region protrudes from the inside of the delivery sheath to the outside, and the second row is housed in the delivery sheath. , It becomes as follows. That is, in this case, the distal end in the first row expands in diameter and returns to the original diameter, while the proximal end in the first row has the same diameter as the distal end in the second row, as described above. Therefore, it does not return to the original diameter. Then, as the second row protrudes, the proximal end in the first row also expands in diameter, and when the entire region of the second row protrudes, the distal end in the second row returns to its original diameter. At the same time, the proximal end in the first row also returns to the original diameter.

As described above, in addition to the axial length L2 of the first row (endmost row) in the end region, the axial length L2 of the second row is also relatively short. Therefore, for example, the above-mentioned problem. It is also possible to avoid the possibility that the point (B) will occur. That is, as described above, it is possible to avoid a state in which the proximal end in the first row does not expand sufficiently and the diameter of the first row expands diagonally (tapered state). The diameter on the proximal end side also increases rapidly.

Although the first and second columns have been described as examples here for convenience of explanation, the same applies to the case where the first and second columns are generalized as the Nth column and the (N + 1) column as in the above case. Can be said.

In this way, by forming the plurality of rows (at least two rows) in the end regions Aea and Aeb into the unit structure U2 having the axial length L2 (relatively small peak value), the end region of the stent 11 can be formed. , It becomes easier to expand the diameter earlier. As a result, in the present embodiment, it is possible to further suppress the misalignment of the stent 11 during the above-mentioned treatment.

<2. Modification example>
Subsequently, a modification (modification examples 1 to 4) of the above embodiment will be described. In these modifications 1 to 4, the same components as those in the embodiments and the like are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

[Modification 1]
FIG. 4 is a schematic development view of a configuration example of a main part (near the end regions Aea and Aeb) in the stent (stent 11A) according to the modified example 1, in which the axial direction Z and the circumferential direction R are shown. It is shown along each direction of. The stent 11A of this modification 1 also corresponds to a specific example of the "stent" in the present invention.

As shown in FIG. 4, the stent 11A is composed of a network structure 111A formed by using the wire rod W1. This mesh-like structure 111A corresponds to the mesh-like structure 111 (see FIG. 2) of the embodiment in which the number of columns of the unit structure U2 in each end region Aea, Aeb is changed, and the like. The composition of is basically the same.

Specifically, as shown in FIG. 4, in the end regions Aea and Aeb in the network structure 111A, the number of columns along the axial direction Z of the unit structure U2 having the axial length L2 is one (1). (By row). In other words, in the end regions Aea and Aeb in the network structure 111A, a network pattern formed by arranging a plurality of unit structures U2 side by side along the circumferential direction R is formed in a row.

Even in the stent 11A of the present modification having such a configuration, basically, the same effect can be obtained by the same action as that of the stent 11 of the embodiment.

[Modification 2]
FIG. 5 is a schematic development view of a configuration example of a main part (near the end regions Aea and Aeb) in the stent (stent 11B) according to the modified example 2, in which the axial direction Z and the circumferential direction R are shown. It is shown along each direction of. The stent 11B of this modification 2 also corresponds to a specific example of the "stent" in the present invention.

As shown in FIG. 5, the stent 11B is composed of a network structure 111B formed by using the wire rod W1. This mesh-like structure 111B corresponds to the mesh-like structure 111 (see FIG. 2) of the embodiment in which the number of columns of the unit structure U2 in the end region Aeb is changed, and the other configurations are different. It is basically the same.

Specifically, as shown in FIG. 5, in the end region Aeb in the network structure 111B, the number of rows along the axial direction Z of the unit structure U2 having the axial length L2 is one (one row). It has become. On the other hand, in the end region Aea, the number of rows along the axial direction Z of the unit structure U2 having the axial length L2 is two (two rows), as in the case of the mesh-like structure 111 (2 rows). See FIG. 5). That is, in this mesh-like structure 111B, the number of columns along the axial direction Z of the unit structure U2 having the axial length L2 is different between the one end region Aea and the other end region Aeb. (Asymmetric with each other). In other words, in the network structure 111B, a network pattern formed by arranging a plurality of unit structures U2 side by side along the circumferential direction R is formed in two rows in the end region Aea, and in the end region Aeb. Is formed in a row.

Even in the stent 11B of the present modification having such a configuration, basically, the same effect can be obtained by the same action as that of the stent 11 of the embodiment.

Further, particularly in the stent 11B of this modification, the number of rows of the unit structure U2 having the axial length L2 along the axial direction Z differs between the one end region Aea and the other end region Aeb. Since I made it so, it will be as follows. That is, since the characteristics (deployment profile, etc.) of the stent 11B can be made different between one end region Aea and the other end region Aeb, for example, depending on the use and usage status of the stent 11B, etc. The characteristics can be selectively set. As a result, it becomes possible to improve the convenience when using the stent 11B.

In this modification, the number of columns of the unit structure U2 having the axial length L2 is different (asymmetrical from each other) in one end region Aea and the other end region Aeb. Has been described as an example, but for example, it may be as follows. That is, for example, the size (length) of the axial length L2 may be different from each other in one end region Aea and the other end region Aeb. Further, for example, in one end region Aea and the other end region Aeb, both the number of columns of the unit structure U2 having the axial length L2 and the size of the axial length L2 are different from each other. You may do so.

[Modification 3]
FIG. 6 is a schematic development view of a configuration example of a main part (near the end regions Aea and Aeb) in the stent (stent 11C) according to the modified example 3, in which the axial direction Z and the circumferential direction R are shown. It is shown along each direction of. The stent 11C of this modification 3 also corresponds to a specific example of the "stent" in the present invention.

As shown in FIG. 6, the stent 11C is composed of a network structure 111C formed by using the wire rod W1. This mesh-like structure 111C corresponds to the mesh-like structure 111 (see FIG. 2) of the embodiment in which the braided pattern of the wire rod W1 in the non-end region Am is changed, and other configurations are It is basically the same.

On the other hand, the braided pattern of the wire rod W1 in each of the end regions Aea and Aeb is the same as the braided pattern described above in the mesh-like structure 111 (see FIG. 6). That is, in this mesh-like structure 111C, the braided pattern of the wire rod W1 is different between the non-end region Am and the end regions Aea and Aeb.

(Example of composition of braided pattern in non-end region Am)
Here, with reference to FIG. 6, a configuration example of a braided pattern in the non-end region Am in the mesh-like structure 111C of this modified example will be described in detail.

As shown in FIG. 6, the braided pattern in the non-end region Am in the mesh-like structure 111C is formed by a wire rod W1 having a corrugated shape including a straight portion s1 and a bent portion b1. Specifically, the braided pattern in the non-end region Am will be described below by exemplifying the braided pattern in the first to third rows on the end region Aea side. That is, as shown in FIG. 6, the braided patterns in the first to third rows on the end region Aea side are the intersection of the wire rods W11a and W11b, the intersection of the wire rods W12a and W12b, and the wire rod W13a. , W13b intersect with each other.

More specifically, as shown in FIG. 6, the wire rod W11a and the wire rod W11b are arranged so as to intersect each other (form a wire rod intersection) in their straight line portion s1. The wire rod W13a and the wire rod W13b are arranged so as to intersect each other in their straight line portions s1. The wire rod W12a and the wire rod W12b are arranged so as to intersect each other in their straight line portions s1.

Further, as shown in FIG. 6, the connecting portion C12 is formed by connecting the intersection (wire intersection) between the wires W11a and W11b and the bent portion b1 of the wires W12a or the wire W12b to each other. ing. The connecting portion C14 is formed by connecting the intersection (wire intersection) between the wires W13a and W13b and the bent portion b1 of the wires W12a or the wire W12b to each other. The connecting portion C13 is formed by connecting the intersection (wire intersection) between the wires W12a and W12b and the bent portion b1 of the wires W11a and W13a or the bent portion b1 of the wires W11b and W13b to each other. ing.

As described above, the braided pattern in the non-end region Am includes the straight portion s1 and the bent portion b1 to form a corrugated wire rod W1 (the above-mentioned wire rods W11a, W11b, W12a, W12b, W13a, W13b, etc.). Is formed by advancing along the circumferential direction R, and is configured by connecting the mesh patterns along the axial direction Z. The bent portion b1 in the wire rod W11a and the bent portion b1 in the wire rod W13a are arranged so as to be adjacent to each other. Similarly, the bent portion b1 in the wire rod W11b and the bent portion b1 in the wire rod W13b are arranged so as to be adjacent to each other.

Further, as shown in FIG. 6, each unit structure U1 in such a non-end region Am is formed by a region surrounded by six wire rods W1 (wire rods W11a, W11b, W12a, W12b, W13a, W13b, etc.). It is configured. Specifically, each unit structure U1 has a substantially rhombic shape in which the axial direction Z is the major axis direction and the circumferential direction R is the minor axis direction, and the two bent portions b1 and the two wire rod intersections are the vertices. It has become. Therefore, also in this modification, the axial length L1 in each unit structure U1 coincides with the wave height of each wire rod W11a, W11b, W12a, W12b, W13a, W13b in the non-end region Am (see FIG. 6). ..

Here, also in the network structure 111C in the stent 11C of the present modification, the axial length L1 of each unit structure U1 in such a non-end region Am and each unit structure U2 in the end regions Aea and Aeb The magnitude relationship with the axial length L2 is as follows. That is, as shown in FIG. 6, the axial length L2 in the end regions Aea and Aeb is relatively shorter than the axial length L1 in the non-end region Am. That is, the magnitude relationship (axial length L2 <axial length L1) is satisfied.

(Action / effect)
Even in the stent 11C of the present modification having such a configuration, basically, the same effect can be obtained by the same action as that of the stent 11 of the embodiment.

Further, particularly in the stent 11C of this modified example, the braided pattern of the wire rod W1 in the network structure 111C is set to be different between the non-end region Am and the end regions Aea and Aeb. become that way.

That is, first, in the braided pattern in the non-end region Am in the mesh-like structure 111C, the stent (stent 11C) is compared with the braided pattern in the non-end region Am in the mesh-like structures 111, 111A, 111B. ) Can improve the diameter expansion force. Therefore, in the stent 11C of this modification, the diameter expansion force in the non-end region Am is improved, and in the end regions Aea and Aeb, as described above, the diameter is expanded early when deployed. It has an easy structure. In this way, in this modification, the stent 11C is made by making the braided pattern in the end regions Aea and Aeb a pattern that is relatively easy to expand in diameter as compared with the braided pattern in the non-end region Am. When deployed from within the delivery sheath, the diameter can be expanded earlier. As a result, in the stent 11C of this modified example, it is possible to further suppress the misalignment during the above-mentioned treatment.

[Modification 4]
FIG. 7 is a schematic development view of a configuration example of a main part (near the end regions Aea and Aeb) in the stent (stent 11D) according to the modified example 4, in which the axial direction Z and the circumferential direction R are shown. It is shown along each direction of. The stent 11D of this modification 4 also corresponds to a specific example of the "stent" in the present invention.

As shown in FIG. 7, the stent 11D is composed of a network structure 111D formed by using the wire rod W1. This mesh-like structure 111D corresponds to the mesh-like structure 111 (see FIG. 2) of the embodiment in which the unit structure U2 in the end region Aeb is changed to the unit structure U1 and has another configuration. Is basically the same.

Specifically, as shown in FIG. 7, the end region Aeb in the network structure 111D is formed by arranging a plurality of unit structures U1 having an axial length L1 side by side along the circumferential direction R. It is composed of a mesh pattern. In other words, in the network structure 111D of the stent 11D, the network pattern constituting Aeb is the same as the network pattern constituting the non-end region Am. On the other hand, in the end region Aea, the number of rows along the axial direction Z of the unit structure U2 having the axial length L2 is two (two rows), as in the case of the mesh-like structure 111 (2 rows). See FIG. 7). That is, in this mesh-like structure 111D, a mesh pattern formed by arranging a plurality of unit structures U2 having an axial length L2 side by side along the circumferential direction R is formed only in one end region Aea. ing.

As described above, the stent 11D of the present modification is as follows, unlike the stents 11, 11A to 11C described so far. That is, the axial length L2 is relatively shorter than the axial length L1 only in one end region of both end regions Aea and Aeb in the stent 11D ((L2 <L1)). Meet).

Even in the stent 11D of the present modification having such a configuration, basically, the same effect can be obtained by the same action as that of the stent 11 of the embodiment.

<3. Application example>
Subsequently, an example of application of the stents (stents 11, 11A to 11D) according to the above-described embodiment and modifications 1 to 4 to medical devices will be described.

FIG. 8 is a schematic perspective view showing a schematic configuration example of a medical device (medical device 1) according to this application example. The medical device 1 includes any of the stents 11, 11A, 11B, 11C, and 11D described above, and the tubular member 12 described below. The medical device 1 is a device applied to a tubular organ in the body such as a digestive tract or a blood vessel. Specifically, the medical device 1 is a medical device such as a covered stent or a stent graft applied to a blood vessel for treatment of aortic dissection.

(Cylindrical member 12)
The tubular member 12 has a cylindrical (cylindrical) shape as shown in FIG. 8, and is arranged so as to cover (cover) at least a part of the stent 11 (11A to 11D). Specifically, in this example, the tubular member 12 is arranged so as to cover the outer peripheral side of the stent 11 (11A to 11D).

Further, the tubular member 12 is connected to the stent 11 (11A to 11D) by means such as sewing, adhesion, and welding, and covers the stent 11 (11A to 11D). The connecting portion between the tubular member 12 and the stent 11 (11A to 11D) may be, for example, an end region Aea, Aeb or a non-end region Am (intermediate region) in the stent 11 (11A to 11D). Is provided as appropriate.

Here, in the example of FIG. 8, the stent 11 (11A to 11D) is arranged in all the regions (end regions Aea, Aeb and non-end regions Am) along the axial direction Z of the tubular member 12. ing. However, the present invention is not limited to this example, and the stent 11 (11A to 11D) may be arranged only in a part of the region along the axial direction Z of the tubular member 12. That is, the region where the stent 11 (11A to 11D) is arranged (stent arrangement region) and the region where the stent 11 (11A to 11D) is not arranged (stent non-arrangement) along the axial direction Z of the medical device 1 Area) and may be possessed.

Examples of such a tubular member 12 include a resin formed into a tubular shape by a molding method such as extrusion molding or blow molding, a knitted fabric made of a resin fiber formed into a tubular shape, a knitted fabric made of an ultrafine metal wire, and a tubular body. It is possible to use a non-woven fabric made of resin or ultrafine metal formed in a shape, a resin sheet or porous sheet formed in a tubular shape, a structure formed in a thin tubular shape using a resin dissolved in a solvent, and the like. can.

Here, as the above-mentioned knitted fabric, known knitted fabrics and woven fabrics such as plain weave and twill weave can be used. It is also possible to use pleated ones such as crimped ones.

Examples of the above-mentioned resin include polyolefins such as polyethylene, polypropylene and ethylene-α-olefin copolymers, and polyesters such as polyamide, polyurethane, polyethylene terephthalate, polybutylene terephthalate, polycyclohexane terephthalate and polyethylene-2,6-naphthalate. , Vinyl chloride resin such as polyvinyl chloride, vinyl acetate, ethylene-vinyl acetate copolymer, fluororesin such as polyethylene fluoride and propylene polyfluoride, polyamide, polyamide elastomer, polyurethane, silicone resin, natural rubber, etc. A resin or the like having little tissue reaction can be used. Of these, polyesters such as polyethylene terephthalate, fluororesins such as polyfluoroethylene and polyfluorinated propylene, and silicone resins, which are chemically stable, have high durability, and have little tissue reaction, can be preferably used. ..

Also in the medical device 1 of this application example, basically, the same effect can be obtained by the same operation as that of the embodiments and the modified examples 1 to 4.

Further, in particular, in the case of a stent graft applied to a blood vessel for the treatment of aortic aneurysm or aortic dissection, for example, the following effects can be obtained. That is, in some cases, the stent graft applied to such a blood vessel cannot be operated accurately at the time of indwelling, and may be displaced from the target site. In addition, there are cases where the stent graft moves from the indwelling site due to migration. Then, blood may flow into the aneurysm and rupture, or blood may flow into the pseudocavity and tear to the adventitia of the blood vessel, resulting in bleeding. From these facts, it can be said that suppressing the displacement during treatment as in the medical device 1 of this application example has a great clinical effect.

<4. Other variants>
Although the present invention has been described above with reference to embodiments, modifications and applications, the present invention is not limited to these embodiments and can be modified in various ways.

For example, the shape, arrangement position, size, number, material, and the like of each member described in the above-described embodiment are not limited, and other shapes, arrangement positions, sizes, numbers, materials, and the like may be used. Specifically, for example, in the above-described embodiment, the number of rows along the axial direction Z of the unit structure U2 having the axial length L2 is one (one row) or two in the end regions Aea and Aeb. The case of two (two columns) has been described as an example, but the present invention is not limited to this example. That is, the number of such rows may be about 1 to 10 rows depending on the length of the entire stent and the length of the axial length L2. Further, the tubular member may cover the inner peripheral side of the stent or both the inner peripheral side and the outer peripheral side of the stent.

Further, the arrangement shape (braided pattern) of each wire rod in the stent is not limited to the one described in the above embodiment, and may be another arrangement shape.

Further, in the above application example, the case where only one stent is arranged in the medical device has been described as an example, but the present invention is not limited to this, and two or more stents are individually placed in the medical device (for example,). , They may be arranged so as to be separated from each other along the axial direction Z).

In addition, in the above-described embodiment and the like, the case where the stent is constructed by using one kind of wire rod (strand wire) has been described, but the case is not limited to this case. That is, for example, a stent may be configured by using a plurality of types (two or more types) of wire rods (wires) having different wire diameters from each other.

Further, in the above-described embodiment and the like, the stent and the medical device applied to the treatment of the gastrointestinal tract such as the large intestine have been mainly described as examples, but the present invention is not limited to this. That is, each of the stent and the medical device of the present invention can be applied to the treatment of a gastrointestinal tract other than the large intestine and a tubular organ in the body other than the gastrointestinal tract such as a blood vessel such as an aorta.

Claims (5)

A stent applied to a tubular organ in the body
It comprises a mesh structure formed of the same wire and having a tubular structure extending along the axial direction of the stent.
In the mesh-like structure, a plurality of unit structures configured by using the same wire rod are arranged side by side in each of both end regions and non-end regions along the axial direction.
The unit structure in the at least one end region of both end regions as compared to the first axial length, which is the axial length of the unit structure in the non-end region. The length in the second axial direction, which is the length along the axial direction, is relatively short .
The braided pattern of the wire rod in the mesh structure is different from each other in the non-end region and the at least one end region, and also
Due to the addition of the braided pattern in the non-end region, the placement density of the wire rod in the braided pattern in the non-end region is such that the arrangement density of the wire rod in the braided pattern in the at least one end region is the same. A stent that is higher than the placement density of the wire. In the at least one end region
The stent according to claim 1, wherein the unit structure having the second axial length has a plurality of rows arranged side by side along the axial direction. The first circumferential length, which is the length along the circumferential direction orthogonal to the axial direction, in the unit structure of the non-end region.
The second circumferential length, which is the length along the circumferential direction in the unit structure of the at least one end region, is
They are almost the same as each other
The stent according to claim 1 or 2. In both end regions, the length in the second axial direction is relatively shorter than the length in the first axial direction, and the length in the second axial direction is relatively short.
At least one of the number of columns arranged side by side along the axial direction of the unit structure having the second axial length and the magnitude of the second axial length is
The stent according to any one of claims 1 to 3, wherein one end region and the other end region of both end regions are different from each other. Cylindrical member and
With at least one stent located on at least a portion of the tubular member.
The stent is
It has a network structure formed by using the same wire rod and having a tubular structure extending along the axial direction of the stent.
In the mesh-like structure, a plurality of unit structures configured by using the same wire rod are arranged side by side in each of both end regions and non-end regions along the axial direction.
The unit structure in the at least one end region of both end regions as compared to the first axial length, which is the axial length of the unit structure in the non-end region. The length in the second axial direction, which is the length along the axial direction, is relatively short .
The braided pattern of the wire rod in the mesh structure is different from each other in the non-end region and the at least one end region, and also
Due to the addition of the braided pattern in the non-end region, the placement density of the wire rod in the braided pattern in the non-end region is such that the arrangement density of the wire rod in the braided pattern in the at least one end region is the same. Medical equipment that is higher than the placement density of wire rods.

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