Method for manufacturing a stent

Abstract

To provide a production method of a stent easily adjusting an axial length in the middle of the production, having little restriction on positions of crossing wire rods each other and the number thereof, and improving a degree of freedom when producing the stent.SOLUTION: A production method of a stent 1 to be placed in a body lumen, the production method includes a skeleton-part forming step of braiding wire rods 11 and 12 to form a tubular skeleton part 10. In the skeleton-part forming step, the wire rods are folded back in an axial direction AX to extend in the circumferential direction, while forming bent portions 10a and 10b, and to form cells C from one end E1 to the other end E2 in the axial direction of the stent by crossing the wire rods each other and engaging bent portions facing in the axial direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a stent. [Background technology]

[0002] Conventionally, stents are known that are placed in narrowed or obstructed areas in biological lumens such as blood vessels, esophagus, bile duct, trachea, and ureter, and expand the diameter of the diseased area to maintain the patency of the biological lumen (see, for example, Patent Document 1). Patent Document 1 discloses a method for manufacturing a stent in which a wire is bent from one axial end of the stent to the other end to first form some elements of diamond-shaped cells, and then the wire is bent from the other axial end of the stent to the one end to form the entire diamond-shaped cell. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6420918 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the manufacturing method disclosed in Patent Document 1 and other publications, diamond-shaped cells are formed by folding back the wire at the other axial end of the stent, which results in fixed positions of one and the other ends of the stent in the axial direction, making it difficult to adjust the axial length of the stent during manufacturing. In addition, since the wires are arranged at their intersections in a regular (helical) pattern, it is not possible to manufacture stents in which the wires are arranged at their intersections in an irregular pattern.

[0005] An object of the present invention is to provide a method for manufacturing a stent in which the axial length can be easily adjusted during manufacturing and there are no restrictions on the positions or number of crossings of wires. [Means for solving the problem]

[0006] The method for producing a stent according to the present invention comprises the steps of: A method for manufacturing a stent to be placed in a biological lumen, comprising the steps of: A skeleton forming step of braiding wires to form a tubular skeleton, In the skeleton forming step, Using a jig to which pins can be detachably attached, a predetermined number of the pins are attached to predetermined positions on the outer circumferential surface of the jig, The wire is folded back in the axial direction to form a bent section. The bent portion is locked to the pin already attached to the outer peripheral surface of the jig. The wires are extended in a circumferential direction while being stretched, and cells are formed by the intersection of the wires and the engagement of the bent portions opposed to each other in the axial direction from one end portion of the stent to the other end portion in the axial direction. tree, The skeleton forming step includes: The method further includes a mounting step of mounting a predetermined number of the pins in a circumferential direction on the outer circumferential surface of the jig as the skeleton forming step progresses. . Effect of the Invention

[0007] According to the present invention, the axial length can be easily adjusted during production, and there are fewer restrictions on the positions and number of crossing wires, thereby improving the degree of freedom when producing a stent. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a stent according to an embodiment. [Diagram 2] FIG. 2 is an enlarged view of a portion of the skeleton. [Diagram 3] FIG. 3 is a diagram showing a jig used in manufacturing a stent. [Figure 4] 4A and 4B are diagrams showing an example of a method for manufacturing a stent. [Diagram 5] 5A and 5B are diagrams showing an example of a method for manufacturing a stent. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic diagram showing a stent 1. Fig. 2 is an enlarged view of a portion of the framework 10. In Fig. 1, each stage of the framework 10 is shown separately, and in Fig. 2, the wires 11 and 12 forming the framework 10 are shown separately. The stent 1 is placed at a lesion (e.g., a narrowed or blocked area) in a biological lumen such as the digestive tract, and is applied to expand the lesion radially outward. The stent 1 has a cylindrical shape that defines a tubular flow path through which fluids such as blood and digestive materials flow.

[0010] The stent 1 is a so-called bare stent, which is composed only of a framework 10 formed into a cylindrical shape by braiding wires 11 and 12. Here, the wires 11 and 12 may be composed of physically different wires, or may be composed of a single wire divided into two at approximately the center as a boundary, as shown in Fig. 3. Note that the length of the wires 11 and 12 can be easily extended by adding another wire to the other end side.

[0011] The skeleton 10 is a fence-type skeleton in which diamond-shaped cells C (mesh) are arranged vertically and horizontally. The skeleton 10 is formed, for example, by extending the wires 11 and 12 in the circumferential direction while folding back in a zigzag (Z-shape) at a predetermined pitch, and by weaving the wires 11 and 12 together so that the opposing peaks 10a and valleys 10b among the peaks 10a protruding toward one end E1 in the axial direction AX and the valleys 10b protruding toward the other end E2 are meshed with each other. Hereinafter, when there is no need to distinguish between the peaks 10a and the valleys 10b, they are referred to as "bent portions 10a, 10b."

[0012] The framework 10 has so-called self-expandability, in which the shape of the expanded state is memorized, and expands radially outward when released from a sheath (not shown) of a stent placement system (not shown). That is, the stent 1 is configured to be deformable from a contracted state in which it is folded radially inward to an expanded state in which it expands radially outward to define a tubular flow path.

[0013] Examples of materials for the wires 11 and 12 forming the skeleton 10 include known metals or metal alloys such as stainless steel, Ni-Ti alloy (nitinol), titanium alloy, etc. Also, an alloy material having X-ray contrast properties may be used. In this case, the position of the stent 1 can be confirmed from outside the body. The skeleton 10 may be formed of materials other than metal materials (e.g., ceramics, resin, etc.).

[0014] The material, wire diameter (cross-sectional area), number of folds in the circumferential direction and fold shape (number and shape of bent parts) of the wires 11 and 12 forming the skeleton 10, as well as the size of the cell C (amount of skeleton per unit length) are appropriately selected based on the expansion force and flexibility of the stent 1 required depending on the biological lumen in which it is to be placed.

[0015] In the following, the “N”th stage (N=1, 2, . . . ) of the skeleton portion 10 formed on the same circumference will be referred to as “unit skeleton B N As shown in FIG. 2, the unit skeleton B in the "N"th stage adjacent to the axial direction AX is called N and unit skeleton B at the "N+1" level N+1 Then, the Nth cell C N is formed. Intersections 10c are formed at the portions where the wires 11, 12 transition from the Nth stage to the (N+1)th stage. Note that, in each stage of the skeleton 10, the circumferential positions at which the intersections 10c are provided may be shifted regularly or irregularly, or may be aligned along the axial direction AX.

[0016] The skeleton 10 is formed by the skeleton forming process described below. In the skeleton forming process, as shown in Fig. 3, a jig 2 is used having a cylindrical outer circumferential surface 21 on which a large number of pin mounting holes H are regularly arranged. Pins P, which will engage with the bent portions 10a, 10b of the skeleton 10, are attached to the pin mounting holes H according to the design of the skeleton 10. By using the jig 2 to which the pins P can be detached, the arrangement of the pins P can be freely changed according to the design of the skeleton 10, and various forms of skeleton 10 can be formed.

[0017] In the following description, the side corresponding to one end E1 of the skeleton 10 is defined as the first row, and the pin mounting holes H in the “n”th row arranged on the same circumference of the jig 2 are defined as “pin mounting holes H n " Also, the "n"th row pin mounting hole H n When distinguishing between the m-th pin mounting hole H and the m-th pin mounting hole H, the m-th pin mounting hole H is defined in the first circumferential direction D1 as "H (n,m) Similarly, the pin P attached to the pin attachment hole H is called "pin P n " or "Pin P (n,m) " It is called.

[0018] In this embodiment, one of the wires 11 is connected to the pin P in the “n”th row adjacent in the axial direction AX. n and pin P in the "n+1" row n+1 The other wire 12 is extended in the first circumferential direction D1 while being alternately engaged with the pins P n and Pin P (n+1) The Nth stage unit skeleton B is extended in the second circumferential direction D2 while being alternately engaged with the N Form.

[0019] A specific example of the skeleton forming step will be described with reference to Figures 4A, 4B, 5A, and 5B. Figures 4A, 4B, 5A, and 5B show the pins P or pin mounting holes H in plan view when the jig 2 is cut in the axial direction AX and developed in the circumferential direction. Note that the pins P or pin mounting holes H from the 8th row onwards in the axial direction AX and the 11th row onwards in the circumferential direction are omitted.

[0020] In FIG. 4A, a first-stage unit skeleton B1 is formed by using the first and second rows of pins P1 and P2 attached to the first and second rows of pin attachment holes H1 and H2 of the jig 2. Specifically, the wires 11 and 12 are alternately engaged with the pins P1 and P2, and the eighth pin attachment hole H in the second row to which the pin P is not attached (2,8) At this portion, the wires 11 and 12 cross each other to form an intersection 10c. Here, by not attaching the pin P to the portion where the intersection 10c is formed, the worker can know the position where the wires 11, 12 should be moved to the next row without being particularly conscious of the position where the intersection 10c is formed.

[0021] Then, in order to form the second-stage unit skeleton B2, the third row of pins P3 are attached to the third row of pin attachment holes H3 of the jig 2. N Before forming the "N+1" stage unit skeleton B N+1 Pin P for forming N+1 (Installation process) The pins P for forming the unit skeletons B of the next and subsequent stages are added sequentially so as not to interfere with the work, but may be attached, for example, at the time of forming the unit skeleton B1 of the first stage.

[0022] Next, as shown in FIG. 4B and FIG. 5A, the pins P2 in the second row and the pins P3 in the third row are used to form the second-stage unit skeleton B2. Specifically, as shown in Fig. 4B, starting from the ninth pin P(3,9) in the third row, one wire 11 is extended in the first circumferential direction D1 while being alternately engaged with pins P2 and P3 (engaging step). In this engagement step, the wire 11 is passed from above or below through the valley portion 10b of the first-stage unit skeleton B1 engaged with the pin P2, thereby performing a weaving step such that the valley portion 10b of the first-stage unit skeleton B1 and the peak portion 10a of the second-stage unit skeleton B2 mesh with each other. As a result, a part of the second-stage unit frame B2 is formed. (3,3) At this position, the wire 11 is moved to the third stage.

[0023] Also, as shown in Figure 5A, the seventh pin in the third row, P (3,7)Starting from the pin P2, the other wire 12 is extended in the second circumferential direction D2 while being alternately engaged with the pins P2 and P3 (engaging step). In this engagement step, the wire 12 is passed from above or below the valley portion 10b of the first-stage unit skeleton B1 engaged with the pin P2, thereby performing a weaving step such that the valley portion 10b of the first-stage unit skeleton B1 and the peak portion 10a of the second-stage unit skeleton B2 mesh with each other. As a result, the entire second-stage unit frame B2 is formed. Then, the pin mounting holes H (3,3) At this position, the wire 12 is moved to the third stage to form an intersection 10c (intersection step).

[0024] As described above, the first line of cell C1 is formed by combining the unit skeleton B1 in the first row and the unit skeleton B2 in the second row, which are shifted by 1 / 2 period in the circumferential direction. Furthermore, by repeating these steps, the third-stage unit skeleton B3, the fourth-stage unit skeleton B4, and so on are successively formed as shown in FIG. 5B. Then, the second-stage unit skeleton B2 and the third-stage unit skeleton B3 are interlocked to form the second-line cell C2, and the third-stage unit skeleton B3 and the fourth-stage unit skeleton B4 are interlocked to form the third-line cell C3. That is, the "N"-stage unit skeleton B adjacent to each other in the axial direction AX is formed. N and unit skeleton B at the "N+1" level N+1 Then, the Nth cell C N is formed (see Figure 2).

[0025] In this manner, in the skeleton forming process, a predetermined number of lines of cells C are formed from one end E1 side toward the other end E2 side in the axial direction AX. Then, although not shown in the figure, after the skeleton 10 is formed up to the other end E2, the tip ends (free ends) of the wires 11, 12 are connected to each other using, for example, a crimping member.

[0026] In this manner, the manufacturing method of the stent 1 according to the embodiment includes a skeletal portion formation step of braiding the wires 11, 12 to form the tubular skeletal portion 10. In the skeletal portion formation step, the wires 11, 12 are folded back in the axial direction AX to form bent portions 10a, 10b while extending circumferentially, and cells C are formed from one axial end E1 of the stent 1 toward the other axial end E2 by the intersection of the wires and the interlocking of the bent portions 10a, 10b facing each other in the axial direction AX.

[0027] As a result, the position of the other axial end E2 is uncertain during the manufacture of the stent 1, and the length of the framework 10 can be freely extended by weaving the wire rods 11, 12. In addition, the position at which the wire rods 11, 12 cross each other can be freely set. Therefore, according to the manufacturing method of the stent 1 according to the present embodiment, the length of the axial direction AX can be easily adjusted during manufacture, and there are fewer restrictions on the positions and number of crossings of the wire rods 11, 12, improving the degree of freedom when manufacturing the stent 1.

[0028] In the skeleton forming process, a jig 2 is used to detachably attach pins P to which the bent portions 10a and 10b are engaged, and a predetermined number of pins P are attached to predetermined positions on the outer circumferential surface 21 of the jig 2 to form the cells C. That is, if all the pins P required to form the entire skeleton 10 are attached in advance, if the attachment positions of the pins P are incorrect at an early stage, it will take a lot of time and effort to reattach the pins P. Also, if more pins P than necessary are attached, they will get in the way when forming the skeleton 10. In contrast, by attaching the pins P in stages according to the formation of the cells C, the arrangement of the pins P can be freely changed in accordance with the design of the skeleton 10, and it is possible to flexibly respond to the formation of various forms of skeleton 10.

[0029] Specifically, the skeleton forming step includes a locking step of locking the bent portions 10a, 10b to the pins P already attached to the outer circumferential surface 21 of the jig 2, and an intersection step of intersecting the wires 11, 12. By weaving the wires 11, 12 using the attached pins P, the skeleton 10 having a predetermined shape and the intersection portion 10c can be easily formed.

[0030] The skeleton forming process further includes an attachment process of newly attaching a predetermined number of pins P in the circumferential direction to the outer peripheral surface 21 of the jig 2 as the skeleton forming process progresses. Therefore, the wires 11, 12 that intersected in the intersecting process can be locked to the newly attached pins P in the attachment process to form the bent portions 10a, 10b. By increasing the number of pins P as the skeleton forming process progresses, it is possible to prevent the locking process from being hindered by pins P that are attached more than necessary, and the locking process and the intersection process can be carried out smoothly.

[0031] The invention made by the inventor has been specifically described above based on an embodiment, but the present invention is not limited to the above embodiment and can be modified within the scope of the gist of the invention.

[0032] In the above embodiment, in the skeleton formation process, cells C are formed while a predetermined number of pins P are attached to predetermined positions on the outer peripheral surface 21 of the jig 2. However, this is merely an example and is not limited to this. For example, all pins P may be attached to predetermined positions on the outer peripheral surface 21 of the jig 2 in advance.

[0033] In the skeleton forming step, the cells C may be formed in the entire axial portion of the skeleton 10 from one end E1 to the other end E2 of the skeleton 10, or in a part of the axial portion of the skeleton 10. For example, the cells C may be formed in one direction in a middle portion excluding both ends (one end E1, the other end E2), in a portion from one end E1 to a midpoint in the axial direction, or in a portion from a midpoint in the axial direction to the other end E2.

[0034] Furthermore, in the above embodiment, the stent 1 is formed as a whole from one skeleton 10 formed in the skeleton forming step, but this is merely an example and is not intended to be limiting. For example, although not shown, the stent may be formed to have a predetermined shape (e.g., a "Y" shape) by combining multiple skeletons each formed in a skeleton forming step.

[0035] In the above embodiment, the unit skeleton B and the intersections 10c are formed one stage at a time, but the skeleton 10 of the same shape can be formed by other methods. For example, after a plurality of stages of unit skeletons B are partially formed by one wire rod 11, the other wire rod 12 may be extended in the second direction to sequentially form the remaining portions of the unit skeletons B and the intersections 10c.

[0036] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0037] 1 Stent 10 Skeleton 10a Mountain section (bend section) 10b Valley (bending part) 10c Intersection 11, 12 Wire rod AX Axial direction E1 One end in the axial direction E2 Other axial end C Cell

Claims

1. 1. A method for manufacturing a stent to be placed in a biological lumen, comprising: A skeleton forming step of braiding wires to form a tubular skeleton, In the framework formation step, a jig to which pins can be attached detachably is used, a predetermined number of the pins are attached to predetermined positions on the outer peripheral surface of the jig, and the wire is folded back in the axial direction to form bent portions while being extended in the circumferential direction while engaging the bent portions with the pins already attached to the outer peripheral surface of the jig. Cells are formed from one axial end of the stent toward the other axial end by the intersection of the wires and the engagement of the bent portions facing each other in the axial direction. The skeleton forming step includes: The method further includes a mounting step of mounting a predetermined number of the pins in a circumferential direction on the outer circumferential surface of the jig as the framework forming step progresses. A method for manufacturing a stent.

2. The skeleton forming step includes: a crossing step of crossing the wires; The method of claim 1 , comprising:

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