JP2002253682A - Stent and stent member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent which achieves a higher dilation rate and a higher retaining accuracy along with a production at a less cost. SOLUTION: Stent members 12 and 13 in dilation each present a circular arc in the shape of the cross section thereof and all of the stent members 12 and 13 are combined to make a roughly cylindrical stent 10. A number of engaging protrusions 12a are formed on both end rims of the stent member 12 and a number of mesh-like mating holes 13a as engaged parts are formed on both end rims of the stent member 13. The engaging protrusions 12a of the stent member 12 are fitted into the mating holes 13a of the stent member 13 adjacent thereto and thus, the stent members 12 and 13 are engaged with each other to make a stent 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of inserting a blood vessel or esophagus of a body into a tubular tissue and placing it in a stenosis to secure the inner diameter of the stenosis, or placing it in an aneurysm to reinforce the blood vessel And a stent for achieving the above.

[0002]

2. Description of the Related Art Conventionally, as a stent of this type, a wire is used to form a pantograph, a coil, a bent wire, a mesh or a lattice. , Etc. are known. In any case, this wire is formed into the above shape, the wires are connected to each other at appropriate locations to form a surface, and as a whole, a tubular body having a closed cross-sectional shape is formed, and the inside of the blood vessel is formed. In this way, it is possible to maintain an enlarged state of a predetermined diameter.

[0003] Before being placed in a blood vessel or the like, the stent is configured to be reduced in diameter so that it can be housed in a catheter.
It is inserted to the target site, and is pushed out of the catheter at the target site, where it is expanded in diameter and fixed at that site.

[0004]

By the way, while the width of a blood vessel being inserted through a blood vessel with this catheter is about 5 mm, the width of a target portion to be fixed, for example, an aneurysm, is 40 to 40 mm. The stent may be as large as about 60 mm, and a high expansion rate is required for the stent. However, it is extremely difficult for a conventional self-expanding type stent to have an expansion rate of 8 to 12 times.

Further, while the width of the target portion varies depending on the patient or the affected area, the expansion rate of the stent or the diameter in the expanded state is constant, so that it is difficult to adapt the stent to each patient or each affected area. There is also a problem. For example, if a stent that is too large is placed in the target site, it may cause damage to the tubular tissue, and if a stent that is too small is placed in the target site, it cannot be fixed securely. There is a risk.
For this reason, various types of stents must be prepared according to the size of the target site, which causes an increase in cost.

Further, in the conventional stent, in order to increase the expansion rate in the radial direction, the lateral strain when accommodated in the catheter in a reduced diameter state increases, and the stent tends to greatly expand in the axial direction in the catheter. . That is, since the change in the axial expansion of the stent between the inside of the catheter and when the stent is pushed out of the catheter is large, it is difficult to predict the axial position when pushing out the catheter, and it is difficult to accurately place the stent at the target site. There is also the problem of difficulty.

[0007] The present invention has been made in view of such problems, and its object is to provide a large expansion rate,
Another object of the present invention is to provide a stent that can be manufactured at low cost or can have high placement accuracy.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention relates to a stent comprising a plurality of easily deformable stent members which can be separated from each other. Has an unclosed shape, and each stent member is engaged with an adjacent stent member to form a closed cross-sectional shape as a whole.

In this stent, since the stent members can be separated, each stent member is separated, deformed, housed in a catheter, and inserted into a target site by the catheter. Then, when reaching the target site, the stent member is
By pushing out the catheter one by one and engaging with each other, a stent having a closed cross-sectional shape is assembled and placed at a target site.

[0010] Since the stent is composed of a plurality of stent members which can be engaged with each other, even if the expansion rate of each stent member is not so large, a large stent can be formed for the stent member. As a result, the degree of expansion of the stent with respect to the stent member can be increased. Also, each stent member can be kept small within the catheter because its cross-sectional shape is not closed.

Alternatively, by changing the number of the stent members constituting the stent, the size of the stent after the engagement of the stent members can be appropriately adjusted, and the stent adapted to the size of the target portion can be formed. Can be.

Furthermore, the degree of expansion of each stent member does not need to be so large, and since the cross-sectional shape thereof is not closed, it can be stored in the catheter small. The extension in the axial direction can be reduced, and the change in the extension in the axial direction between the housed state and the pushed state can be reduced. Therefore, the stent member can be accurately placed at the target site.

[0013] The engagement of the stent member may be of any configuration, but the invention according to claim 2 is the invention according to claim 1, wherein the both ends of each stent member are provided with an engagement portion or a cover. An engaging portion is formed, and the engaging portion or the engaged portion engages with an engaged portion or an engaging portion formed on an edge of an adjacent stent member. According to a third aspect of the present invention, there is provided an easily deformable sheet-shaped stent member, which has an engaging portion or an engaged portion for engaging with another stent member at both end edges thereof, It is characterized in that a cylindrical stent can be formed by engaging with another stent member.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. The following embodiments do not limit the present invention.

FIGS. 1 to 3 show a first embodiment of the present invention.
Is composed of a plurality of stent members 12 and 13. Each of the stent members 12 and 13 has a wire formed in a pantograph shape, a coil shape, a bent shape, a mesh shape, a lattice shape, or any other shape. It is made up of structured. Alternatively, in addition to the wire member shown in the drawing, it is also possible to use a single sheet material having easy deformability.

The material of the wire or sheet material is as follows:
Stainless steel, tantalum, platinum, shape memory alloy (N
i-Ti system, Cu-Al-Ni system, Cu-Zn-Al
System, Pd-Ti system, Be-Cu system, amorphous, etc.),
Either plastic or plastic monofilament (polyester, polyurethane, polyolefin, polytetrafluoroethylene, porosiloxane, shape memory resin, etc.) or the like can be selected.

Each of the stent members 12, 13 has an arcuate cross-sectional shape in an expanded state, that is, is not closed, and is substantially in a state in which all the stent members 12, 13 are combined. The stent 10 has a closed cylindrical cross section. For this purpose, a large number of engaging projections 12a serving as engaging portions are formed on both end edges of the stent member 12, and mesh-like engaging portions serving as engaging portions are provided on both end edges of the stent member 13. Many holes 13a are formed. Then, the engagement protrusion 12a of the stent member 12 is engaged with the engagement hole 13 of the adjacent stent member 13.
a, whereby the stent members 12, 13 are engaged with each other to form the stent 10, and when the engagement between the engagement protrusion 12a and the engaged hole 13a is released, Separate from each other. In this example, one stent 10 is constituted by two stent members 12 and two stent members 13, but the number of stent members 12, 13 is arbitrary, and the size of the target site for installing the stent 10 By adjusting the number to match
The diameter of the stent 10 can be adjusted.

In the stent 10 configured as described above, prior to placement, the stent members 12 and 13 are separated from each other as shown in FIG.
It is housed in series within 0. In the catheter 40,
Each of the sheet-shaped stent members 12 and 13 is deformed and accommodated. The method of deformation is not limited to the method in which both edges are rounded as shown in the figure, but may be any shape such as a completely wound shape or a folded shape. Since the cross-sectional shape of each stent member 12, 13 is not closed, it can be housed compactly. In addition, the stent members 12 and 13 correspond to positions when the stent 10 is configured, as shown in FIGS. 4B to 4E.
The orientations are rotated by 90 degrees (360 degrees ÷ the number of stent members).

After being inserted into the target portion while being housed in the catheter 40, the stent members 12, 13 are sequentially pushed out of the catheter 40 one by one at the target portion. At this time, it is arranged in the blood vessel according to the direction in each catheter 40. After extruding the first stent member 12, the subsequent stent members 13, 1
In the case of extruding 2, it is necessary to extrude while paying careful attention so as to be engaged with the already extruded stent member, but a large number of engaging projections 12 a and engaged holes 13 a are formed. At the same time, by increasing the area of the portion where the engaging protrusions 12a and the engaged holes 13a are formed to secure a wide overlapping portion between the adjacent stent members 12, 13, each engaging protrusion 12a is formed by a large number of covered portions. So as to fit into any of the engagement holes 13a,
The engagement can be reliably performed.

Further, in this embodiment, since the stent 10 is composed of the plurality of stent members 12 and 13, the expansion rate of each stent member 12 and 13 does not need to be so large. The change in elongation in the axial direction between the pushed state and the pushed state is small. Therefore, since it is possible to accurately align the target portion with the target portion, it is possible to accurately align the next stent member even when the next stent member is engaged with the already pushed-out stent member while being pressed. Can be reliably engaged. As a result, the assembled stent 10 can be accurately placed at the target site.

In this way, since the stent is constituted by the plurality of stent members, the size of the stent can be made large in accordance with the width of the target portion.

FIGS. 5 and 6 show a second embodiment of the present invention. In the figure, the same members as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The stent 20 of this embodiment is a covered stent (stent with an artificial blood vessel) in which covers 22 and 23 are provided outside the stent members 12 and 13 to prevent blood leakage. Suitable for placement in aneurysms. As a material of the covers 22 and 23, any of polyester, silicone resin, polytetrafluoroethylene, polyolefin, polyurethane, polyvinylpyrrolidone, polyhydroxymethyl methacrylate and the like can be selected, and a stent member is formed by dipping or casting. Coating outside 12 and 13.

The cover 23 on the outer side of the stent member 13 is formed so that no gap is formed between the cover 22 and the cover 23.
And the cover 22 on the outside of the stent member 12 has a large overlapping amount, and the cover 23 and the cover 22 surely overlap.

The cover 23 of the stent member 13 is coated only on the central portion excluding both end edges so as not to cover the engagement holes 13a at both end edges of the stent member 13. .

In the stent configured as described above, the same operation and effect as those of the first embodiment can be obtained, and
The covers 22 and 23 can prevent blood from leaking.

FIGS. 7 and 8 are views showing a third embodiment of the present invention. In the figure, the same members as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The stent 30 of this embodiment is composed of a plurality of stent members 14, and each stent member 14
Is the same as the stent members 12 and 13 except for both end edges, but differs from the stent members 12 and 13 in that an engagement protrusion 14a is formed at one end edge and an engagement hole 14b is formed at the other end edge. ing. The engagement hole 14b of each stent member 14 has an engagement protrusion 14 of the adjacent stent member 14.
a, the stent 30 is configured by the plurality of stent members 14 being engaged with each other, and the engagement protrusion 14a of the stent member 14 and the engaged hole 14b of the adjacent stent member 14 are formed. Are released from each other. In this example, one stent 30 is constituted by three stent members 14, but the number of stent members 14 is arbitrary, and the number is adjusted so as to be adapted to the size of the target portion where the stent 30 is installed. Thereby, the diameter of the stent 30 can be adjusted.

In this embodiment, the same operation and effect as those of the first embodiment can be obtained, and the manufacturing cost can be further reduced because only one kind of stent member 14 is required. In addition, the second outside of each stent member 14 is
It is also possible to provide a cover similar to the embodiment.

[0030]

As described above, according to the present invention, a large stent can be assembled because the stent is composed of a plurality of mutually engageable stent members. A large stent can be configured for the stent member, and as a result, the degree of expansion of the stent relative to the stent member can be increased.

Alternatively, according to the present invention, the size of the stent can be appropriately adjusted by adjusting the number of the stent members, so that it can be adapted to the target site. Since there is no need to prepare various types of stents in accordance with the size of the target site, it can be manufactured at low cost.

Further, the degree of expansion of each stent member does not need to be so large, and since the cross-sectional shape thereof is not closed, it can be accommodated in the catheter. The extension in the axial direction can be reduced, and the change in the extension in the axial direction between the housed state and the pushed state can be reduced. Therefore, the stent member can be accurately placed at the target site.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a stent according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the stent taken along line 2-2 of FIG.

FIG. 3 is an exploded perspective view of FIG. 1, showing only three stent members for explanation.

4A is a perspective view showing a state in which the stent member of FIG. 1 is housed in a catheter and a part of the stent member is pushed out, and FIG. 4B is a view along a line bb of FIG. (C) is a cross-sectional view taken along line cc of (a), (d) is a cross-sectional view taken along line dd of (a), (e) is a cross-sectional view taken along line ee in (a).

FIG. 5 is a perspective view showing a stent according to a second embodiment of the present invention.

6 is a cross-sectional view of the stent taken along line 6-6 of FIG.

FIG. 7 is a perspective view illustrating a stent according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view of the stent taken along line 8-8 of FIG. 7;

[Explanation of symbols]

 10, 20, 30 Stent 12, 13, 14 Stent member 12a Engagement projection 13a Engagement hole 14a Engagement projection 14b Engagement hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C167 AA02 AA43 AA44 AA47 AA50 AA54 BB11 BB15 BB16 BB20 BB40 CC09 CC10 DD08 FF05 GG02 GG36 GG42 HH18 HH30

Claims (3)

[Claims] 1. A stent comprising a plurality of easily deformable stent members separable from each other, wherein each stent member has an unclosed cross-sectional shape, and each stent member has an adjacent stent. A stent having a closed cross-sectional shape as a whole by engaging with a member. 2. An engaging portion or an engaged portion is formed at both ends of each stent member, and the engaging portion or the engaged portion is formed at an edge of an adjacent stent member. The stent according to claim 1, wherein the stent engages with the engaged portion or the engaging portion. 3. An easily deformable sheet-shaped stent member having an engaging portion or an engaged portion for engaging with another stent member at both end edges thereof. A stent member capable of forming a cylindrical stent by being engaged.