DE10323475A1 - Medical stent implant has numerous adjacent cells laterally transposed rows - Google Patents

Abstract

A stent (26) medical implant has numerous adjacent cells (26, 28) in rows (32). At least two cells in each row (32) are transposed laterally to the cells in the adjacent rows. Alternatively, individual V-shaped shanks (36) within the cells are curved.

Description

The The invention relates to a stent and its use for implantation in a living body, with a large number of adjacent cells arranged in rows are arranged. Furthermore The invention relates to a stent for implantation in a living Body, with a multitude of adjoining cells, the walls of which each Wall sections are formed, two of which are essentially V-shaped Wall sections opposite each other are arranged and on. their thigh ends through curved bridge sections are interconnected. In particular, the invention relates the use of an intraluminal stent for implantation in lumens with different properties. Such different characteristics of lumens can different curvatures, Side branches, variable diameters or different compliant lumen walls his.

stents These types are used to channel different living bodies, such as e.g. Blood vessels, esophagus, urethra, kidney ducts, through Expand a tubular stent structure to protect against collapse or sealing inside the channel and / or as a carrier of drugs in body channels a to enable at least local therapy. The stent must be radial be expandable in the channel to support the channel wall. Furthermore must the Stent in the expanded state be flexible or tubular, around the support function to enable also in curved duct or core areas. Furthermore, the Stent can also be flexible in the compressed state to be bent through or curvy channels and blood vessels enter to be able to.

Around Various known functional stents achieve this in known stents Geometric elements combined as wall sections to form a large number of cells, that adjoin each other. The individual wall sections are more specific Way, for example curved or straight, designed to give the stent the desired deformation properties to lend. To enable the stent to expand radially, so-called Zig-Zag structures are formed, which are connected by bridges are. The bridges can deform or flatten when the zig-zag structures are stretched and enable such a tangent-like bend line of the stent.

In 1 and 2 is a well-known stent 10 illustrated, which is formed from a plurality of cells, of which a first cell with 12 and a second cell with 12 ' is designated. Every single cell 12 . 12 ' is with four straight wall sections 14 designed, being between two straight wall sections 14 a concave wall section 16 is in the form of a folded edge. Between the straight wall sections opposite in this way 14 there are two curved wall sections 18 ,

A single section of wall 18 forms in the first cell 12 a convex wall section between two adjacent concave wall sections 20 lies. At the same time forms the wall section 18 in the second cell 12 'a concave wall section between two convex wall sections 22 is arranged. The straight wall sections 14 form two opposite V-shaped legs, each at their leg ends by a curved bridge section 18 are connected. The single cell 12 is axisymmetric to the circumferential direction of the stent, ie in relation to 1 in the vertical direction.

In other words, with the wall sections 16 . 20 and 22 one connection node each 24 formed on the two straight and a curved wall section 14 respectively. 18 connect.

The single cell 12 of a known stent 10 is successively in the circumferential direction from a first straight wall section 14 , a first concave wall section 16 , a second straight wall section 14 , a first concave wall section 20 , a first convex wall section 18 , a second concave wall section 20 , a third straight wall section 14 , a second concave wall section 16 , a fourth straight wall section 14 , a first convex wall section 22 , a second concave wall section 18 and a second convex wall section 22 formed, which eventually to the first straight wall section 14 borders.

Stents designed in this way 10 have a so-called radial and a so-called axial component during deformation. This means that they expand or contract in the radial and axial direction of the channel or lumen into which they are inserted. The stent is expanded in the radial direction while at the same time contracting in the axial direction. The radial component is created by spreading the straight wall sections 14 on the concave wall section 16 generated. The wall sections 18 serve as bridges or connectors between the straight wall sections 14 , They have the task of being in the expanded and unexpanded state of the stent 10 ensure its flexibility.

In known stents, the walls of the cells are partially covered with medication, which is possible should be distributed as evenly as possible on the vessel wall. It is therefore desirable that the walls of the cells are supported as evenly as possible on the vessel wall. Known stents, however, lead to a relatively uneven covering of a channel or vessel wall with the walls of the cells.

Furthermore known stents often have insufficient flexibility in compressed and even in the expanded state. The above axial component leads a known stent during of expansion to an axial shortening of the stent and one unequal contact pressure to the vessel wall sections, which is undesirable is.

task the invention is to overcome the disadvantages mentioned above and in particular to provide a stent that is inexpensive to manufacture is and at the same time has a high variability in the expansion.

The Invention is solved with a stent mentioned at the beginning which is related to at least two cells in a row on the circumferential direction or the azimuthal direction of the stent laterally offset relative to each other, i.e. in the axial direction are, as well as with a stent, in which the individual legs of the essentially V-shaped Wall sections are curved are.

The stent according to the invention, in which at least two cells in a row in succession are laterally offset relative to one another in the axial direction of the stent, has a considerably better set-up behavior than conventional stents. In particular, the stent expands more evenly in the radial direction. In the freely expanded state, such a stent has along its axis, ie with reference to 1 in a horizontal direction, to a substantially equal extent. Crimping on balloon catheters is also advantageously possible.

at the stent according to the invention with two essentially V-shaped ones Wall sections arranged opposite each other and on their thigh ends by curved Connection or bridge sections are interconnected, increase the curved Thigh the flexibility of the Set up stents and leave local deformations if necessary on the stent.

The Invention can be particularly useful in balloon-expanded stents preferably made of stainless steel or cobalt-chrome-tantalum alloy be used.

at The cells are an advantageous further development of the invention a row arranged at least in sections helically.

By Develop a regular structure in the stent, with rows in which the cells are arranged helically about that In addition, an overall homogeneous stent can be created.

The individual cells of the stent according to the invention are advantageous at least in sections essentially point symmetrical and the centers of symmetry of cells in a row essentially offset from each other on a helix or azimuthal arranged.

alternative can the individual cells, at least in sections, essentially axisymmetric be formed and the axes of symmetry in a row successive Cells essentially form a helix or azimuthal to each other are offset.

Around the lateral or azimuthal offset of at least two in one Row of successive cells related to the axial direction to produce the stent relative to one another are advantageous individual cells from two opposite essentially V-shaped Wall sections formed, the leg ends by curved bridge sections are interconnected, the individual legs of the in essential V-shaped Wall sections are of different lengths.

A uniform expansion of the stent according to the invention is also advantageous to achieve in that one of the legs essentially concave and the opposite in relation to the adjacent bridge section Leg is essentially convex.

alternative is advantageously one of the legs substantially concave and the related to the adjacent bridge section opposite legs also essentially concave.

The Expansion behavior can be further improved by the bridge sections in the lateral surface of the stent considered drop-shaped are.

Furthermore it is advantageous if the bridge sections in the lateral surface considered the stent are essentially Ω-shaped.

The following are exemplary embodiments of a stent according to the invention with reference to the accompanying schematic drawings. Show it:

1 a stent according to the prior art in the compressed state,

2 a stent according to 1 in the expanded state,

3 a first embodiment of a stent according to the invention and

4 a second embodiment of a stent according to the invention.

In 3 is a stent according to the invention 26 with a first cell 28 and a second cell 30 illustrated. The cells 28 respectively. 30 are in rows 32 along the circumferential direction of the stent 26 arranged, one of which is in 3 also as a dashed line 34 is illustrated. In other words, the cells essentially form a plurality of rows along an axial direction of the stent, the rows being arranged circumferentially or offset or adjacent to one another in the azimuth direction.

The individual cells 28 and 30 are each formed with two opposite V-shaped wall sections in the axial direction of the stent, the legs of which in 3 with the reference symbol 36 are labeled. The thigh 36 of a single V-shaped wall section are concavely or convexly curved, such that the opposite, essentially V-shaped wall sections refer to the center of the individual cells 28 respectively. 30 are essentially point symmetrical.

The ends of the thighs 36 are each over connecting or bridge sections 38 connected, according to the embodiment 3 are drop-shaped, preferring a tapered neck area 38A and an enlarged distal head area in this regard 38B exhibit. The bridge area 38 starts at one opposite the respective cell 28 . 30 inner region of a connecting section 39 between the thighs 36 of two substantially V-shaped wall sections adjacent in the axial direction.

The bridge section preferably extends 38 to about the middle or a central area of the respective cell 28 . 30 ,

In 4 is an embodiment of a stent according to the invention 26 which is essentially like the stent 26 according to 3 is constructed. The thigh 36 of the stent 26 according to 4 are of different lengths, however, so that the cells 28 and 30 formed rows to the circumferential direction 34 (see solid line in 4 ) at an angle in a range from approximately 5 ° to approximately 45 °, preferably approximately 10 ° to approximately 30 °, most preferably approximately 20 ° (see 4 ) are inclined. In other words, two cells are adjacent along the axial direction 28 . 30 of the same series 32 offset from one another, ie displaced with respect to one another in the azimuth direction.

The thigh 36 of a single, essentially V-shaped wall section are also designed to be concave and convex in such a way that two mutually opposite, essentially V-shaped wall sections are arranged essentially axially symmetrically.

According to the embodiment, between the ends of the legs 4 essentially Ω-shaped bridge sections 38 ' educated. These differ from the teardrop-shaped bridge sections 38 the 3 due to a larger ratio between the azimuthal extension of the head area 38'b to that of the neck area 38'a , The Ω-shaped bridge section also extends 38 ' shorter in the axial direction than the teardrop-shaped bridge section 38 the 3 , so that the Ω-shaped bridge section 38 ' essentially not in the inner area of each cell 28 . 30 extends, which is defined by the two substantially V-shaped wall sections. The Ω-shaped bridge section 38 'sets on an outer area of the connection area 39 the legs to be connected 36 of the opposite substantially V-shaped wall sections and thus extends along the axial direction essentially in a region A of a connecting region of two adjacent legs 36 of two axially adjacent (arranged in the same direction) substantially V-shaped wall sections of two adjacent cells 28 . 30 equivalent. In contrast, the bridge area 38 the 3 a longer extension in the axial direction, so that the bridge area 38 itself in the inner area of each cell 28 . 30 extends into it.

The wall cross sections of the bridge sections 38 ' are compared to the cross sections of the legs 36 weaker trained. The bridge sections 38 ' are therefore particularly easy to deform.

The stents described above 26 according to 4 where the two are in a row 32 successive cells 28 and 30 in the axial direction of the stent 26 relative to each other laterally or in the azimuthal direction 34 are staggered, has a significantly better expansion or installation behavior than conventional stents. The stent 26 especially expands more evenly in the radial direction. In the freely expanded state, such a stent 26 along its axis, ie related to 4 in a horizontal direction, to a substantially equal extent. Crimping on balloon catheters is also advantageously possible.

With the stent 26 according to 3 with two substantially V-shaped wall sections, which are arranged opposite one another and at their leg ends by curved bridge sections 38 are connected to each other, increase the curved legs 36 the flexibility of the stent 26 when setting up and if necessary leave local deformations on the stent 26 to.

The stents 26 are particularly advantageously made of stainless steel or cobalt-chrome-tantalum alloy. Thus the stents 26 preferably expanded in the body by an expansion device such as a balloon catheter. The invention or a preferred embodiment thereof is preferably used for balloon-expanded stents made of stainless steel, tantalum, niobium and cobalt alloys. Stents made of other materials such as polymers, self-degradable materials (e.g. lactic acid materials or derivatives), as well as stents made of nitinol (nickel-titanium alloys) and / or other self-expandable materials or (preferably temperature-dependent) shape memory materials are also conceivable become.

10

stent according to the status of the technique

12

first cell

12 '

second cell

14

straight wall section

16

concave wall section

18

wall section or bridge

20

concave wall section

22

convex wall section

24

junction

26

stent according to the invention

28

first cell

30

second cell

32

string

34

circumferentially

36

leg

38 38 '

bridge section

38A, 38'a

 neck

38B, 38'b

head area

39

connecting area

A

Extension area in the axial direction of the bridge area 38 '

Claims (14)

Stent ( 26 ) for implantation in a living body, in particular intraluminal stent, with a large number of adjoining cells ( 28 and 30 ) in rows ( 32 ) are arranged, characterized in that at least two in a row ( 32 ) successive cells ( 28 and 30 ) related to the axial direction of the stent ( 26 ) are laterally offset relative to each other. Stent according to claim 1, characterized in that the cells ( 28 and 30 ) a row ( 32 ) are arranged helically at least in sections. Stent according to claim 1 or 2, characterized in that the cells ( 28 and 30 ) of the rows ( 32 ) are arranged helically. Stent according to one of claims 1 to 3, characterized in that the individual cells ( 28 and 30 ) are at least partially essentially point-symmetrical ( 3 ) and the centers of symmetry of cells in a row 28 and 30 ) are arranged essentially on a helix. Stent according to one of claims 1 to 4, characterized in that the individual cells ( 28 and 30 ) are at least partially essentially axially symmetrical ( 4 ) and the axes of symmetry of cells in a row ( 28 and 30 ) essentially form a helix. Stent according to one of claims 1 to 5, characterized in that the individual cells ( 28 and 30 ) are formed from two opposite V-shaped wall sections, the leg ends of which are formed by curved bridge sections ( 38 ) are connected to each other, the individual legs ( 36 ) of the V-shaped wall sections are of different lengths in order to offset the lateral displacement of at least two cells in a row ( 28 and 30 ) related to the axial direction of the stent ( 26 ) relative to each other ( 4 ). Stent, in particular according to one of the preceding claims, for implantation in a living body, in particular intraluminal stent, with a large number of adjoining cells ( 28 and 30 ), the walls of which are each formed from wall sections, of which two V-shaped wall sections are arranged opposite one another and at their leg ends by curved bridge sections ( 38 ) are connected to each other, characterized in that the individual legs ( 36 ) the V-shaped wall sections are curved. Stent according to claim 7, characterized in that one of the legs ( 36 ) concave and related to the adjacent bridge section ( 38 ) opposite legs ( 36 ) is convex. Stent according to claim 7, characterized in that one of the legs ( 36 ) concave and related to the adjacent bridge section ( 38 ) opposite legs ( 36 ) is also concave. Stent according to one of claims 6 to 9, characterized in that the bridge sections ( 38 ) in the outer surface of the stent ( 26 ) considered drop-shaped ( 3 ) are trained. Stent according to one of claims 6 to 10, characterized in that the bridge sections ( 38 ) in the outer surface of the stent ( 26 ) is essentially Ω-shaped ( 4 ). Stent according to one of claims 1 to 11, characterized in that that it is made of stainless steel. Stent according to one of claims 1 to 12, characterized in that that it’s made from cobalt chrome tantalum. Using a stent ( 26 ) according to one of claims 1 to 13 as a balloon-expanded stent.