The present invention relates to stent wires and a method of manufacturing such stent wires and stents, and more particularly, to stent wires which are manufactured by casting such that shapes are different according to portions, a method of manufacturing such stent wires by casting, and a method of manufacturing stents each of which is configured such that annular stent wires can be stacked on and connected to each other.
In general, a blood vessel may have angiostenosis due to a blood clot, arteriosclerosis or so on, or an aneurysm in which a part of the blood vessel expands like a balloon due to aging or other diseases.
In a location of the blood vessel where angiostenosis or an aneurysm has occurred, a surgical operation is generally conducted. Replacement with an artificial blood vessel or bypass grafting is thereby performed in the corresponding location. Such a surgical operation has problems in that it leaves a large scar since a large incision has to be made in the diseased area, and that the effectiveness of the surgical operation is not so great. In addition, the same problems as those occur with the stricture of the throat, biliary stricture, the stricture of the urethra, and the blockage or stricture of other internal organs, as well as transjugular intrahepatic portosystemic shunt (TIPS).
For this reason, a variety of techniques for simply treating the above-described diseased area, such as the stricture of a body part or an aneurysm in a blood vessel, instead of performing the surgical operation has been recently disclosed. One of these techniques is treatment using a stent made of a shape memory metal. Stents are divided into non-vascular stents which are used in the throat or the internal organs and vascular stents which are used in blood vessels. Non-vascular stents are manufactured by the process of netting wires into a hollow cylindrical shape, since they have a predetermined minimum size. Vascular stents are manufactured by the process of cutting a base material using a laser, since it is difficult to machine vascular stents into a precise shape via the wire netting because of the very small size of vascular stents.
However, the manufacture of stents by the netting has drawbacks in that a separate netting jig is required, and that the complicated netting process makes the manufacturing difficult. In addition, in the case of manufacturing stents using the laser cutting technique, devices for the laser cutting as well as a very precise machining technique are necessarily required. This accordingly leads to the problem of the increased manufacturing cost.
In addition, since a stent wire is typically manufactured by drawing such that it has the shape of a straight line, it is required that both ends of a linear stent be connected in order to make a ring-shaped stent. However, when the both ends of the linear stent wire are connected to each other, there is a risk of damage to the internal organ or the blood vessel since the joint is not smooth. In addition, the process of connecting the stent wire is also required. This consequently makes the manufacturing process complicated and thus increases the manufacturing cost, which is problematic. In addition, when the stent wire has the joint as mentioned above, there is a problem in that the strength of the joint is weaker than that of the other portions, thereby reducing lifespan. It may be necessary to manufacture individual portions of the stent having various shapes depending on the environment or conditions where the stent is used. When the stent wire is manufactured by the drawing as mentioned above, there is a drawback in that the stent wire cannot be manufactured such that individual portions thereof have various sizes or shapes. Accordingly, a separate machining process is required in order to change the size or shape of each portion of the stent wire, thereby making the stent wire manufacturing process complicated and increasing the manufacturing cost, which is problematic.
It is, of course, possible to freely change the size or shape of each portion of a stent when manufacturing the stent by the laser cutting technique. However, the laser cutting devices are necessarily required and a very precise machining technique is required, thereby leading to the drawback of the increased manufacturing cost.
The present invention has been made to solve the foregoing problems with the prior art, and therefore an object of the present invention is to provide a method of manufacturing stents, which can simplify a manufacturing process and increase the lifespan of stent wires by interconnecting a plurality of stent wires in a stacking fashion while enhancing the strength of joints between two adjacent stent wires.
An object of the present invention is to provide a stent wire which is manufactured by casting such that its shape differs according to the portion. Also provided is a method of manufacturing stent wires, in which an annular stent wire can be manufactured by a single process, such that the size and shape of each portion of the stent wire can be variously formed without a separate machining process.
According to an aspect of the invention for realizing the foregoing object, provided is a method of manufacturing stents. The method includes: a first step of preparing at least three or more stent wires, each of which has an annular shape in a plan view, and includes peaks and valleys which alternate with each other; a second step of interconnecting the first and second stent wires such that predetermined peaks of the second stent wire are caught by predetermined valleys of the first stent wire, wherein the first and second stent wires are interconnected in a repeated pattern in which two consecutive peaks of the second stent wire are caught by two consecutive valleys of the first stent wire and one subsequent peak of the second stent wire is uncaught by one subsequent valley of the first stent wire; and a third step of connecting the third stent wire to the second stent wire by moving down valleys of the third stent wire to pass between the valleys of the first stent wire and the peaks of the second stent wire so that predetermined peaks of the third stent are caught by predetermined valleys of the second stent wire.
The second step may include causing the predetermined peaks of the second stent wire to be caught by the predetermined valleys of the first stent wire in a process of positioning the second stent wire above the first stent wire and then moving at least one of the first and second stent wires in the top-bottom direction.
The third step may include causing the peaks of the third stent to be caught by the valleys of the second stent wire in a process of positioning the third stent wire above the second stent wire and then moving down the third stent wire.
According to another aspect of the invention for realizing the foregoing object, provided is a method of manufacturing stents. The method includes: a first step of preparing at least three or more stent wires, each of which has an annular shape in a plan view, and includes peaks and valleys which alternate with each other; a second step of interconnecting the first and second stent wires such that predetermined peaks of the second stent wire are caught by predetermined valleys of the first stent wire, wherein the first and second stent wires are interconnected in a repeated pattern in which two consecutive peaks of the second stent wire are caught by two consecutive valleys of the first stent wire and one subsequent peak of the second stent wire is uncaught by one subsequent valley of the first stent wire; and a third step of connecting the third stent wire to the first stent wire by moving up peaks of the third stent wire to pass between the valleys of the first stent wire and the peaks of the second stent wire so that predetermined valleys of the third stent are caught by predetermined peaks of the first stent wire.
The second step may include causing the predetermined peaks of the second stent wire to be caught by the predetermined valleys of the first stent wire in a process of positioning the second stent wire above the first stent wire and then moving at least one of the first and second stent wires in a top-bottom direction.
The third step may include causing the peaks of the third stent to be caught by the valleys of the second stent wire in a process of positioning the third stent wire above the second stent wire and then moving down the third stent wire.
Each number of the peaks and the valleys may be set to a multiple of 3.
The first step may include manufacturing the stent wires by casting.
In each of the stent wires, the thickness of the peaks and the valleys may be greater than the thickness of remaining portions.
The first step may include a process of manufacturing the stent wires, each of which has a shape of a planar looped curve, and includes alternating outward and inward protrusions, and a process of bending each of the stent wires so that the outward protrusions are positioned above the inward protrusions, whereby the bent outward protrusions form the peaks, and the bent inward protrusions form the valleys.
The method may further include a fourth step of connecting the valley and the peak which are disposed at corresponding positions and are uncaught by each other.
The fourth step may include binding the valley and the peak using a separate connecting wire.
A fastening portion having a through-hole may be provided on one of the valley and the peak, which are disposed at corresponding positions and are uncaught by each other, and an extension that is insertable into the through-hole may be provided on the other one of the valley and the peak, which are disposed at corresponding positions and are uncaught by each other. The fourth step may include connecting the valley and the peak to each other by inserting the extension into the through-hole.
The extension may be connected to the fastening portion such that the extension is bent after being inserted into the through-hole. A gap is formed in the top-bottom direction in a connecting portion between the extension and the fastening portion.
According to a further aspect of the invention for realizing the foregoing object, provided is a stent wire that has peaks and valleys which alternate with each other. Each cross-sectional area of the peaks and the valleys is greater than a cross-sectional area of remaining portions.
A fastening portion having on through-hole may be formed in one of each of the valleys and each of the peaks. An extension which is configured so as to be insertable into the through-hole may be formed on the other one of each of the valleys and each of the peaks.
The length of the through-hole in a top-bottom direction may be greater than the thickness of the extension.
The stent wire may be manufactured by casting such that the planar shape thereof forms a looped curve.
According to a further aspect of the invention for realizing the foregoing object, provided is a method of manufacturing stent wires. The method includes: a first step of manufacturing a stent wire which has the shape of a planar looped curve and includes alternating outward and inward protrusions; and a second step of bending the stent wire so that the outward protrusions are positioned above the inward protrusions, whereby the bent outward protrusions form the peaks, and the bent inward protrusions form the valleys.
The first step may include manufacturing the stent wire by casting.
The first step may include forming each cross-sectional area of the outward and inward protrusions to be greater than the cross-sectional area of remaining portions.
The first step may include forming a fastening portion having a through-hole on one of each of the outward protrusions and each of the inward protrusions and an extension on the other one of each of the outward protrusions and each of the inward protrusions, the extension being configured so as to be insertable into the through-hole.
The method of manufacturing stents according to the present invention has the following advantages. It is possible to simplify a manufacturing process and increase the lifespan of stent wires by interconnecting a plurality of stent wires in a stacking fashion while enhancing the strength of joints between two adjacent stent wires. In addition, the stent wire according to the present invention has advantages in that the strength of the peaks and the valleys is enhanced, that coupling between stent wires is facilitated, and that the stent wire does not cause damage to the blood vessel or internal organism since it does not have a joint. Furthermore, the method of manufacturing stent wires according to the present invention has an advantage of being capable of increasing the efficiency of production of stent wires, since a separate machining process for forming the peaks and valleys is not required.
Hereinafter a method of manufacturing stents according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
The method of manufacturing stents according to the present invention is a method of manufacturing a cylindrical stent by connecting a plurality of annular stent wires 100 to each other, and includes a first step of preparing three or more stent wires 100, each of which has an annular shape in a plan view, and includes peaks 110 and valleys 120 which alternate with each other; a second step of interconnecting the first and second stent wires 100a and 100b such that the peaks 110 of the second stent wire 100b are caught by the valleys 120 of the first stent wire 100a; and a third step of interconnecting the second and third stent wires such that the peaks 110 of the third stent wire 100c are caught by the valleys 120 of the second stent wire 100b.
The stent wires 100 are typically manufactured by drawing such that they have the shape of a straight line. Therefore, preferably, the first step of preparing the stent wires 100 having the peaks 110 and the valleys 120 includes a process of manufacturing a ring-shaped base material 1, as shown in
In addition, when interconnecting the first and second stent wires 100a and 100b such that the peaks 110b of the second stent wire 100b are caught by the valleys 120a of the first stent wire 100a as in the second step, as shown in
Here, when all of the corresponding portions of the first and second stent wires, i.e. the valleys 120a of the first stent wire 100a and the peaks 110b of the second stent wire 100b are caught by each other, a further annular stent wire 100, i.e. the third stent wire 100c can be connected to neither the first stent wire 100a nor the second stent wire 100b. The third stent wire 100c may, of course, be connected to the first or second stent wire 100a or 100b by cutting an intermediate portion of the third stent wire 100c and then binding the third stent wire 100c to the peaks 110a of the first stent wire 100a or the valleys 120b of the second stent wire 100b. In this case, however, there is a drawback in that the process of cutting and reconnecting the third stent wire 100c is required.
Therefore, the method of manufacturing stents according to the present invention is characterized in that the first and second stent wires 100a and 100b are not interconnected such that all of the peaks 110b of the second stent wire 100b are caught by the valleys 120a of the first stent wire 100a. Rather, predetermined peaks 110b of the second stent wire 100b are caught by the corresponding valleys 120a of the first stent wire 100a, but the other peaks 110b of the second stent wire 100b are uncaught by the other corresponding valleys 120a of the first stent wire 100a. As shown in
When the other peaks 110b of the second stent wire 100b are uncaught by the other valleys 120a of the first stent wire 100a, a worker can insert the valleys 120c of the third stent wire 100c between the valleys 120a of the first stent wire 100a and the peaks 110b of the second stent wire 100b (the third valley 120a of the first stent wire 100a and the third peak 110b of the second stent wire 100b in
Here, if the peaks 110b of the second stent wire 100b caught by the valleys 120a of the first stent wire 100a and the peaks 110b of the second stent wire 100b uncaught by the valleys 120a of the first stent wire 100a are repeated in a ratio of 2:1, when the third stent wire 100c is connected to the second stent wire 100b by inserting the valleys 120c of the third stent wire 100c between the valleys 120a of the first stent wire 100a and the peaks 110b of the second stent wire 100b and then moving down the third stent wire 100c as described above, all of the peaks 110c of the third stent wire 100c are not caught on the valleys 120b of the second stent wire 100b but only predetermined peaks 110c of the third stent wire 100c are caught on the corresponding valleys 120b of the second stent wire 100b. As shown in
It is, of course, possible to connect the third stent wire 100c to the second stent wire 100b and the fourth stent wire 100d to the third stent wire 100c when the ratio of repeating the peaks 110b of the second stent wire 100b caught by the valleys 120a of the first stent wire 100a and the peaks 110b of the second stent wire 100b uncaught by the valleys 120a of the first stent wire 100a is 3:1 or 2:2 instead of 2:1. In this case, however, there is a risk of damage to connected portions between the stent wires 100 when an external force is applied, since the number of the connected portions between the stents 100 is decreased. Therefore, it is preferable that the adjacent stent wires are interconnected in a repeated pattern in which first two consecutive peaks 110 of one stent wire are caught by first two consecutive valleys 120 of the adjacent stent wire and then one subsequent peak 110 of one stent wire is uncaught by one subsequent valley 120 of the adjacent stent wire, as illustrated in this embodiment. Here, it is preferred that the number of the peaks 110 and the number of the valleys 120 be set to multiples of 3, such that the peaks 110 caught by the valleys 120 and the peaks 110 uncaught by the valleys 120 are repeated in a ratio of 2:1.
In addition, although only the method of connecting two stent wires to each other by the operation of moving down one stent wire 100 that is to be connected has been illustrated in this embodiment, the two stent wires 100 can be connected to each other by the operation of moving up one stent wire 100 that is to be connected. For instance, it is possible to connect the second stent wire 100b to the first stent wire 100a by positioning the second stent wire 100b below the first stent wire 100a and then moving up the second stent wire 100b such that the valleys 120b of the second stent wire 100b are caught by the peaks 110a of the first stent wire 100a, and connect the third stent wire 100c to the second stent wire 100b by inserting the peaks 110c of the third stent wire 100c between the valleys 120a of the first stent wire 100a and the peaks 110b of the second stent wire 100b, which are uncaught by each other, and then moving up the third stent wire 100c such that the valleys 120c of the third stent wire 100c are caught by the peaks 110b of the second stent wire 100b. A detailed description of this method of interconnecting the stent wires 100 by moving up the additional stent wire 100 will be omitted, since the principle and structure thereof for interconnecting the two stent wires are identical to those of the above-described method of interconnecting the stent wires 100 by moving down the additional stent wire 100 except for the direction in which the stent wires are connected.
In the configuration in which some valleys 120 are uncaught by corresponding peaks 110 as shown in
In this case, welding, brazing or the like can be applied as a technique for interconnecting the valley 120a and the peak 110b which are uncaught by each other. However, since the stent wires 100 must be heated for the welding or brazing, the structure of the stent wire 100 may be deformed, thereby causing a problem of an unexpected decrease in the strength. Therefore, it is preferred that the fourth step be applied to interconnect the valley 120a and the peak 110b which are uncaught by each other by binding the valley 120a and the peak 110b together using a separate connecting wire 200, as shown in
When the stent wires 100 are interconnected such that the peaks 110 are selectively caught by the valleys 120 of another stent wire as described above, the peaks 110 and the valleys 120 may be damaged first. This is because, when tension is applied in the lengthwise direction of the stent, the tension is concentrated on the peaks 110 and the valleys 120. Therefore, it is preferable to increase the thickness of the valleys 120 and the peaks 110 in order to improve the endurance of a stent against tension. Since the stent wires 100 are generally manufactured by drawing, the problem is that it is very difficult to make only the valleys 120 and the peaks 110 thick. In addition, in the case of manufacturing the stent wires 100 by drawing, the problem is that it is impossible to manufacture an annular stent wire 100 without a joint.
Therefore, it is preferred that the stent wire 100 according to the present invention be manufactured by casting such that the peaks 110 and the valleys 120 are thicker than the other portions. Specifically, the method of manufacturing stents according to the present invention can manufacture the annular stent wire 100 without a joint using a cylindrical inner mold 10 and an outer mold 20, as shown in
In addition, as shown in
In addition, the manufacture of the stent wire 100 by casting is advantageous in that it is possible to easily produce the stent wire 100, in which the thickness t2 of the peaks 110 and the valleys 120 is greater than the thickness t1 of the other portions, by only the operation of forming the top curvature portions of the outer and inner grooves 12 and 22 that are supposed to form the peaks 110 and the bottom curvature portions of the outer and inner grooves 12 and 22 that are supposed to form the valleys 120 such that the inner diameter thereof is greater than that of the other portions. Although only the method of manufacturing the stent wire 100 having the thicker peaks and valleys 110 and 120 has been illustrated in this embodiment, it is of course possible to increase the cross-sectional area of the valleys 120 and the peaks 110 by forming the stent wire 100 by drawing and then adding a reinforcement material to the valleys 120 and the peaks 110.
In addition, when the stent wire 100 is manufactured by casting as described above, the separate machining process for forming the peaks 110 and the valleys 120 becomes unnecessary, thereby advantageously improving the productivity of the stent wire 100.
When interconnecting the valleys 120 and the peaks 110 which are disposed at corresponding positions but are uncaught by each other, the valleys 120 and the peaks 110 can be connected to each other using the separate connecting wire 200, as shown in
Specifically, as shown in
In addition, when the valleys 120a of the first stent wire 100a and the peaks 110b of the second stent wire 100b are coupled to each other, the distance between each valley 120a of the first stent wire 100a and the counterpart peak 110b of the second stent wire 100b is required to be variable so that the length of the stent can vary within a predetermined range when tension is applied to the stent. When the extension 112b is fixedly coupled to the fastening portion 122a, the distance between the valley 120a of the first stent wire 100a and the peak 110b of the second stent wire 100b is not changeable, which is problematic. Therefore, when the extension 112b inserted into the through-hole 124a is bent, it is preferred that a gap be formed in the top-bottom direction in the connecting portion between the extension 112b and the fastening portion 122a. That is, as shown in
In the meantime, the fastening portions 122a and 122b and the extensions 112a and 112b may be added to the stent wire 100 which is manufactured by drawing. In this case, however, the process of manufacturing the fastening portions 122a and 122b and the extensions 112a and 112b and the process of mounting the fastening portions 122a and 122b and the extensions 112a and 112b to the valleys 120 and the peaks 110 are additionally required. This makes the manufacturing process complicated and increases the manufacturing cost, which is disadvantageous. Therefore, when intending to manufacture the stent wires having the fastening portions 122a and 122b and the extensions 112a and 112b, the use of casting is preferable. In addition, the extensions 112a can also be formed on the peaks 110a of the first stent wire 100a and the fastening portions 122b can also be formed on the valleys 120b of the second stent wire 100b, such that the first stent wire 100a and the second stent wire 100b can be connected with a third stent wire 100. Although only the structure in which the fastening portions 122 protrude downward from the bottom of the valleys 120 has been illustrated in this embodiment, the direction in which the fastening portions 122 protrude can be changed into a variety of directions, such as the upward or downward direction.
The process of manufacturing the stent wire 100 which possesses the peaks 110 and the valleys 120 using the inner mold 10 and the outer mold 20, as shown in
Therefore, the method of manufacturing stent wires according to the present invention can be devised such that it forms the peaks 110 and the valleys 120 by a bending process after manufacturing the stent wire 100 having a two-dimensional shape, i.e. a planar shape. Specifically, the method of manufacturing stent wires according to the present invention includes a first step of preparing a stent wire having the shape of a planar looped curve, which includes alternating outward and inward protrusions 101 and 102, as shown in
Although the stent wire 100 having the planar looped curve shown in
In addition, as shown in
While the present invention has been described in detail with reference to the certain exemplary embodiments, the scope of the present invention is not limited to the certain embodiments but shall be construed by the appended claims. In addition, it will be understood by a person having ordinary skill in the art that various modifications and variations can be made without departing from the scope of the present invention.
Number | Date | Country | Kind |
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10-2010-0107248 | Oct 2010 | KR | national |
10-2010-0107249 | Oct 2010 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/KR11/08197 | 10/31/2011 | WO | 00 | 4/29/2013 |