WO2012115376A2

WO2012115376A2 - Expandable stent

Info

Publication number: WO2012115376A2
Application number: PCT/KR2012/000988
Authority: WO
Inventors: 김헌영; 현창백; 유혁상; 이승열; 한숙희; 손영주; 노형진; 김영완; 이광호; 박현식; 윤수진; 김영희
Original assignee: 강원대학교산학협력단
Priority date: 2011-02-25
Filing date: 2012-02-10
Publication date: 2012-08-30
Also published as: WO2012115376A3; KR101064215B1

Abstract

The present invention relates to an expandable stent which does not contract in an axial direction during expansion. The expandable stent has an axial direction, a circumferential direction, and a radial direction. Also, the expandable stent has a cylindrical shape before and after the expandable stent is expanded in the radial direction. The expandable stent includes a plurality of rings, a plurality of first flexible links, and a plurality of second flexible links. The rings are arranged in the axial and circumferential directions. The first flexible links may connect together two rings that are adjacent along the circumferential direction in the links, and may be expandable in the circumferential direction. The second flexible links may connect together two rings that are adjacent along the axial direction in the links, and may be expandable in the axial direction. According to the present invention, since the contraction of the expandable stent in the axial direction during the expansion is minimized by the rings, the stent may be accurately disposed at a position such as in a lumen.

Description

Expandable stent

The present invention relates to an expandable stent, and more particularly to an expandable stent that does not contract in the axial direction upon expansion.

Expandable stent is a medical device for restoring the flow by inserting into the lumen when the passage of lumen such as blood vessels, gastrointestinal tract, biliary tract is abnormally narrowed by the disease or the flow of blood, body fluids, etc. is blocked. In vascular diseases, stents are installed when blood flow is not smooth due to narrowing of the inner diameter of arteries due to the deposition of blood clots and lipids in the arteries. The stent has a cylindrical shape that can be expanded from a small diameter to a large diameter.

The expandable stent can be inserted into the artery through a catheter and move inwards through the patient's arterial path until the unexpanded stent is positioned where desired. Once the stent is in the desired position, the balloon is inflated outwards using a balloon or other mechanism to engage the artery. This expandable stent must retain sufficient rigidity even after it is inflated, and the rigidity must be maintained even after the catheter is removed.

Expandable stents are composed of various shapes and structures to provide adequate performance for various environments. Expandable stents are easily found in many patent documents, including US Pat. Nos. 6,261,318, 5,868,782, and 5,514,154. The stent of these patent documents is configured to be inserted into the lumen and to expand and contract. It is very important that the stent be positioned exactly at the desired location of the lumen. If the length of the stent varies before and after expansion, it is very difficult to position the stent exactly at the desired location. This problem of incorrect positioning is difficult to reverse due to the fact that the stent not only expands easily, but also does not shrink once expanded.

However, the expanded stent of the patent documents as described above has a problem in that the length in the axial direction is reduced when expanded in the radial direction. The stent disclosed in US Pat. No. 5,514,154 has a structure for limiting the contraction in the axial direction, but there is a problem in that the contraction in the axial direction occurs at an end and it is difficult to position the stent at a desired place after expansion.

The present invention is to solve various problems of the prior art as described above. It is an object of the present invention to provide a new expandable stent which does not contract in the axial direction even if it expands in the radial direction and retains strong bearing capacity after the procedure.

It is another object of the present invention to provide an expandable stent that can increase the amount of bending by minimizing interference between the first and second flexibles during bending deformation.

According to one aspect of the invention, an expandable stent is provided. The expandable stent according to the present invention has an axial direction, a circumferential direction and a radial direction, and includes a plurality of rings arranged along the axial direction and the circumferential direction in an expandable stent having a cylindrical shape before and after expansion in the radial direction. ; A plurality of first flexible links connecting two adjacent rings in a circumferential direction of the plurality of rings, the first flexible links being expandable in the circumferential direction; One of the plurality of rings connects two adjacent rings along the axial direction and includes a plurality of second flexible links that can expand along the axial direction.

The expandable stent according to the present invention has an excellent effect of positioning the stent at an accurate position such as the lumen, since the contraction in the axial direction is minimized by the rings during expansion. In addition, the change in the longitudinal direction is minimized, and the reaction force is small when the longitudinal compressive force is applied, thereby minimizing the interference between the first and second flexible links during bending deformation. It works.

1 is a perspective view showing a configuration in which the expandable stent is contracted according to the present invention.

Figure 2 is a perspective view showing a configuration in which the expandable stent is expanded in accordance with the present invention.

Figure 3 is a front view showing a developed configuration in which the expandable stent is contracted according to the present invention.

Figure 4 is a front view showing a developed configuration in which the expandable stent is expanded in accordance with the present invention.

5 and 6 are views for explaining the operation of the first flexible link in the expandable stent according to the present invention.

7 and 8 are views for explaining the operation of the second flexible link in the expandable stent in accordance with the present invention.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments associated with the accompanying drawings.

Hereinafter, preferred embodiments of the expandable stent according to the present invention will be described in detail with reference to the accompanying drawings.

First, referring to FIGS. 1 to 4, the expandable stent 10 according to the present invention has a front open end 20 and a rear open end 22 on both sides, and is closed to insert into the lumen. It consists of a cylindrical cylinder that can move between and an open configuration. The cylindrical stent 10 has an axial direction i, a radial direction j and a circumferential direction k, the diameter of which extends or contracts along the radial direction j.

3 to 6, the expandable stent 10 includes a plurality of rings 30 arranged at intervals along the axial direction i and the circumferential direction k. The rings 30 are aligned along the axial direction i and the circumferential direction k and are formed in a rectangle. The rings 30 are connected to both ends of the first and

second struts

32a and 32b and the first and

second struts

32a and 32b which are arranged in parallel along the circumferential direction k. It consists of a 1st and 2nd loop (Loop: 34a, 34b). The length of the first and

second struts

32a and 32b is longer than the gap between the first and

second struts

32a and 32b. The first and

second loops

34a and 34b are bent outwardly of the first and

second struts

32a and 32b. In this embodiment, the rings 30 may be configured as elliptical as necessary.

Two rings 30 adjacent to each other along the circumferential direction k of the rings 30 are connected by a plurality of first flexible links 40 that can expand along the circumferential direction k. have. 5 and 6, the first flexible link 40 is shown as a hatched portion.

The first flexible links 40 are composed of a plurality of third struts 42a through 42c and a plurality of

third loops

44a and 44b connecting both ends of the third struts 42a through 42c. The third struts 42a to 42c before the expansion of the first flexible links 40 are arranged in parallel along the circumferential direction k. Three to third struts 42a to 42c are shown in FIGS. 3 to 6, and two

third loops

44a and 44b are shown, but this is illustrative and the third struts 42a to 42c are illustrated. The number of

third loops

44a and 44b may be appropriately increased or decreased as necessary.

The first flexible links 40 may include a first finger 46a and a first finger extending from the first strut 42a and the last strut 44c disposed on both sides of the third struts 42a to 42c. 2 fingers 46b are provided. The first finger 46a is connected to the upper one of the two adjacent rings 30 along the circumferential direction k, and the second finger 46b is the two adjacent ones along the circumferential direction k. It is connected to the lower one of the rings 30. The first finger 46a is connected to the first loop 34a and the second finger 46b is connected to the second loop 34b. The first and second ends of the first and

second fingers

46a and 46b are close to the portions where the first and

second struts

32a and 32b and the first and

second loops

34a and 34b are respectively connected. The

loops

34a and 34b are alternately connected.

As shown in FIGS. 3 and 5, the axial length L ₁ of the rings 30 is formed longer than the axial length L ₂ of the first flexible links 40. Although the first flexible links 40 are shown in which the third struts 42a to 42c are arranged in parallel, this is exemplary and the first flexible links 40 are formed in a sinusoidal or "S" shape. S-link, "J" shaped J-link, "N" shaped N-link, "M" shaped M-link, "W" shaped W-link, etc. Can be. In addition, these shaped first flexible links 40 may be arranged inverted.

1 to 4, 7 and 8, two rings 30 adjacent to one of the rings 30 along the longitudinal direction i may be expanded in a plurality of directions along the longitudinal direction i. It is connected by the second flexible links 50. 7 and 8, the second flexible link 50 is shown as a hatched portion.

The second flexible links 50 are composed of a plurality of fourth struts 52a through 52c and a plurality of

fourth loops

54a and 54b connecting both ends of the fourth struts 52a through 52c. 3, 4, 7, and 8, four fourth struts 52a to 52c are shown, and four

fourth loops

54a and 54b are shown, but this is illustrative and the fifth strut ( The number of 52a to 52c and the number of

fourth loops

54a and 54b may be appropriately increased or decreased as necessary.

The second flexible links 50 have a third finger 56a and a fourth finger extending from the first strut 52a and the last strut 52c disposed on both sides of the fourth struts 52a to 52c. 56b is provided. The first finger 56a connects the first fourth strut 52a to the left of the two adjacent rings 30 along the axial direction i, and the fourth finger 56b is the last The fourth strut 52c is connected to the ring on the right side of two adjacent rings 30 along the axial direction i.

The third finger 56a is connected to the second loop 34b, and the fourth finger 56b is connected to the first loop 34a. The first and second ends of the third and

fourth fingers

56a and 56b are close to the portions where the first and

second struts

32a and 32b and the first and

second loops

34a and 34b are respectively connected. The

loops

34a and 34b are alternately connected. The second flexible links 50 may be formed in various shapes like the first flexible links 40. Meanwhile, two rings 30 adjacent along the longitudinal direction i and adjacent along the axial direction i by the arrangement of the rings 30, the first and second

flexible links

40, 50. A plurality of cells is closed between the two second flexible links 50. Although the second flexible links 50 are formed of S-links that are formed in a sinusoidal or "S" shape, it is illustrated that the first flexible links 50 are first flexible links ( Like 40), it may be formed in various shapes.

Expandable stent 10 according to the present invention having such a configuration can be easily and accurately approach the passage of the lumen during the expansion of the stent by the elastic deformation of the first and second flexible links (50). The radial j expansion of the expandable stent 10, ie the expansion of the diameter, is smoothly achieved by the elastic deformation of the first flexible links 40. 5 shows the pre-expansion length L ₃ of the first flexible links 40 and the post-expansion length L ₄ of the first flexible links 40 in FIG. 6.

In addition, the longitudinal j expansion of the expandable stent 10 is smoothly achieved by elastic deformation of the second flexible links 50. In FIG. 7 the pre-expansion length L ₅ of the second flexible links 50 is shown by way of example. An exemplary length L ₆ after expansion of the second flexible links 50 is shown in FIG. 8.

On the other hand, the closed ring 30 has a small expansion rate even if it is not expanded or expanded by the structural shape. That is, the substantial deformation of the rings 30 is made by plastic deformation. Due to the nature of these rings 30, for example, the resistance against pressure and radiological support of the expandable stent 10 against the constriction of blood vessels is improved. Therefore, the contraction of the expandable stent 10 after the procedure can be prevented to minimize the restenosis of blood vessels.

In addition, the change in the longitudinal direction (i) of the stent 10 is minimized by the rings 30 of the closed structure, and the reaction force is generated small when the stent 10 receives the compressive force in the longitudinal direction (i). Therefore, when bending deformation of the stent 10, the interference between the first and second flexible (40, 50) can be minimized to increase the amount of bending, in addition, the longitudinal change is minimized, and the longitudinal compression force Since the reaction force is small and the interference between the first and second flexible links is minimized during bending deformation, it can be easily and accurately installed in the lumen and the like.

The embodiments described above are merely illustrative of the preferred embodiments of the present invention, the scope of the present invention is not limited to the described embodiments, those skilled in the art within the spirit and claims of the present invention It will be understood that various changes, modifications, or substitutions may be made thereto, and such embodiments are to be understood as being within the scope of the present invention.

Claims

In the expandable stent having an axial direction, a circumferential direction and a radial direction, and having a cylindrical shape before and after expansion in the radial direction,

A plurality of rings arranged along the axial direction and the circumferential direction;

A plurality of first flexible links connecting two adjacent rings in the circumferential direction of the plurality of rings and expanding in the circumferential direction;

And a plurality of second flexible links extending along the axial direction and connecting two adjacent rings along the axial direction among the plurality of rings.
The method of claim 1,

And the plurality of rings are aligned along the axial direction and the circumferential direction.
The method according to claim 1 or 2,

And the plurality of rings are formed in a rectangular shape along the axial direction.
The method of claim 3,

The plurality of rings are expanded stents including first and second stuts arranged in parallel in the circumferential direction, and first and second loops formed to connect both ends of the first and second struts, respectively. .
The method of claim 3,

The plurality of first flexible links,

A plurality of third struts arranged along the circumferential direction;

A plurality of third loops formed to connect both ends of the plurality of third struts, respectively;

A first finger connecting the first third strut of the plurality of third struts to an upper ring of two adjacent rings along the circumferential direction;

And a second finger connecting the last third strut of the plurality of third struts to a lower ring of two adjacent rings along the circumferential direction.
The method of claim 5,

And the first and second fingers are connected to the first and second loops, respectively.
The method of claim 6,

And the first and second fingers are connected to the joint portions of the first and second struts and the first and second loops, respectively.
The method of claim 7, wherein

And the first and second fingers are connected symmetrically along the circumferential direction to the joint portions of the first and second struts and the first and second loops, respectively.
The method of claim 3,

The plurality of second flexible links,

A plurality of fourth struts arranged obliquely along the circumferential direction;

A plurality of fourth loops formed to connect both ends of the plurality of fourth struts, respectively;

A third finger connecting the first fourth strut of the plurality of fourth struts to a ring on the left of two adjacent rings along the axial direction;

And an fourth finger connecting the last fourth strut of the plurality of fourth struts to a ring on the right of two adjacent rings along the axial direction.
The method of claim 9,

And the third and fourth fingers are respectively connected to the first and second loops.
The method of claim 9,

And the first and second fingers are connected to the joint portions of the first and second struts and the first and second loops, respectively.
The method of claim 11,

And the first and second fingers are connected symmetrically along the axial direction to the joint portions of the first and second struts and the first and second loops, respectively.