KR19990065081A - Lumen extension stent - Google Patents

Abstract

The present invention relates to a stent disposed inside the lumen of the body. According to an embodiment of the present invention, the stent is cylindrical having a single length of filament, and is located between a zigzag portion in which the filaments are zigzag wound at both ends, and the zigzag portion, and the filament is spirally wound. Included spiral part. The zigzag portion has a straight portion, a peak portion and a valley portion, and forms a band disposed in the circumferential direction of the stent, and a lower band adjacent to the valley portion of the zigzag portion forming a band located at the end of the stent. Zig-zag-shaped peak portions forming the zigzag shape are connected in a twisted manner. The helical portion is connected in a twisted manner with the valley of the lowermost band of the zigzag portion of the upper end of the stent and the valley of the zigzag portion forming the uppermost band of the lower end of the stent.

Description

Lumen extension stent

The present invention relates to a stent for luminal dilatation.

In some cases, it may be desirable to provide a means for expanding the constriction lumen or a means for holding the opening through the lumen.

For example, this may be due to esophageal narrowing caused by esophageal carcinoma or metastasis, or by stenosis caused by cancers of the biliary, urinary and bronchial systems. have.

In this case, ballon dilatation is widely known as a method for expanding and maintaining the esophagus passageway, but the method has to be repeatedly performed because of the temporary effect, and it is not effective for patients with severe stenosis.

As another example, in the case of esophageal stenosis, various artificial esophagus are inserted into the patient's esophagus to maintain the opening, but since it is not contractile and loose, the rate of esophageal rupture in the process of inserting it into the stenosis caused by cancer Is high (30-40%) and mortality from rupture of the esophagus is high. In addition, the patient has a narrow internal diameter (10 to 12 mm) of the artificial esophagus, and has a great difficulty when swallowing food or the like due to the narrowing of the artificial esophagus when the food is ingested.

As a means to overcome the above problems, US Pat. No. 4,214,587 discloses an apparatus for maintaining an expanded passageway using a stent. However, the device of this patent has a temporary effect in passage expansion, but there is still a problem that the lumen narrows after a long time.

In order to solve this disadvantage, US Pat. No. 4,580,568 discloses a stent in which a continuous straight portion in which a wire is formed in a closed zigzag shape is connected by a band. Conventional stents of this type can be elastically compressed to small diameters so that the straight portions are arranged side by side and adjacent to each other for insertion into the lumen. In addition, the stent is elastically self-expandable to a larger second diameter where the straight portion presses against the wall of the passageway and keeps it open. While conventional zigzag stents have proven to be very useful in many cases, their performance tends to decrease as the length of the stent increases.

Self-expanding stents have four performance characteristics: the expansion force the stent imposes on the lumen wall, the minimum diameter the stent can compress during the insertion process, the stent's adaptability to the curved passages inside the patient's body, and the stent's It is common to be assessed for stability that does not migrate from the initial implantation point.

Conventional zigzag stents are relatively short because they are difficult to easily adapt to the lumen of a serpentine patient due to the straight wire portion. One solution to this drawback is to connect multiple short stents end-to-end to create one long zig-zag stent assembly that ameliorates conventional zig-zag stents. While these improved zigzag stents have been improved over conventional zigzag stents for some applications, there is still a need for elongated self-expandable stents having improved performance characteristics by having the advantages of both conventional zigzag stents and improved zigzag stents. do.

In order to solve this problem, a number of stents have been developed, and representative ones of them include a wall type stent and a cook type stent.

PCT publication pamphlet WO93 / 13825 discloses an example of a cook type stent. The self-expanding stent of the patent includes a wire bent in an elongated zigzag pattern having a plurality of substantially straight wire portions separated into a plurality of band portions, and a filament intersecting adjacent the band portion. The zigzag pattern is spirally wound around a central axis of the stent, and a plurality of band portions are spirally arranged. Since the stent has a plurality of filaments connected to each other in a zigzag form, the stent has an excellent restoring force, but has a disadvantage in that structural stabilities are poor.

US Patent No. 4,655,771 discloses an example of a wall type stent. The stent disclosed in the patent includes a flexible tubular body having a diameter that is variable by axial movement of the ends of the body relative to each other and composed of a plurality of rigid but flexible thread elements, wherein Each of the seal elements extends in a spiral shape with the center line of the main body as a common axis. The body consists of a first number of elements having the same winding direction but displaced in mutual axial directions, and a second number of elements intersecting the first number of elements in mutually axially displaced but opposite winding directions. . The first and second elements intersect while being formed at substantially obtuse angles. The stent has a uniform structure as a whole, but the restoring force is slightly reduced. In addition, conventional zigzag stents typically reduce the length of the stent upon expansion.

In view of the foregoing, it is a main object of the present invention to provide a stent having excellent stability as well as structural stability along the length of the stent.

Another object of the present invention is to provide a lumen expanding stent that expands the constricted lumen site for a long time without moving inside the lumen and maintains an open passage through the lumen site.

It is still another object of the present invention to provide a stent having substantially uniform performance along its length so as to be well adapted to the bent portion inside the pulse system into which the stent is implanted.

It is yet another object of the present invention to provide a stent with improved stability in maintaining its position within the lumen of a patient.

1 is a perspective view of the lumen expanding stent according to the first embodiment of the present invention.

2 is a partially enlarged view of FIG. 1;

Figure 3 is a perspective view of the lumen expanding stent according to the second embodiment of the present invention.

Figure 4 is a perspective view of the lumen expanding stent according to the third embodiment of the present invention.

5 is a perspective view of the lumen expanding stent according to the fourth embodiment of the present invention.

6 is a perspective view of the lumen expanding stent according to the fifth embodiment of the present invention, and is substantially the same as the fourth embodiment shown in FIG. 5 except for both ends having a uniform diameter.

Figure 7 is a perspective view of the lumen expanding stent according to the sixth embodiment of the present invention.

FIG. 8 is a perspective view of the lumen expanding stent according to the seventh embodiment of the present invention, and is substantially the same as the sixth embodiment shown in FIG. 7 except for both ends having a uniform diameter.

<Explanation of symbols for main parts of drawing>

100: straight part

102, 102 ', 102: peak portion

104, 104 ', 104: Valley

Ⅰ, Ⅰ ', Ⅰ, Ⅲ, Ⅲ', Ⅲ: Zigzag-shaped part

II, II ', II: spiral part

According to one aspect of the present invention for solving the above object, in the cylindrical lumen expansion stent consisting of a single length of the filament, the zigzag portion and the zig-zag winding the filament is zigzag on both ends of the stent, A stent is provided between the portions, wherein the stent comprises a spiral portion in which the filaments are spiral wound.

The zigzag portion has a straight portion, a peak portion and a valley portion, and forms a band disposed in the circumferential direction of the stent, and a lower band adjacent to the valley portion of the zigzag portion forming a band located at the end of the stent. Zig-zag-shaped peak portions forming the zigzag shape are connected in a twisted manner.

The helical portion is connected in a twisted manner with the valley of the lowermost band of the zigzag portion of the upper end of the stent and the valley of the zigzag portion forming the uppermost band of the lower end of the stent.

If desired, a zigzag portion may be further formed between the spiral portions of the stent.

The upper and lower zigzag portions preferably have a flare shape that extends in diameter toward the distal end or a diameter larger than the diameter of the helical portion to prevent sliding of the stent.

In the above-described lumen expanding stent, the filament is preferably made of a nickel-titanium alloy.

According to the above-described configuration, the lumen expansion stent according to the present invention has a zigzag-shaped portion at both ends, and a spiral portion at the center, thereby having a helical portion having the advantages and excellent flexibility of the zigzag-shaped portion having excellent restoring force Has all the advantages.

Hereinafter, with reference to the drawings will be described in detail the lumen expansion stent according to a preferred embodiment of the present invention.

Figure 1 schematically shows a cylindrical stent according to the first embodiment of the present invention, the stent is composed of a filament of a single length. The stent consists of zigzag portions (I, III) at both ends and a central spiral portion (II). However, one of ordinary skill in the art appreciates that a zigzag portion may additionally be formed in the middle of the helical portion located between both ends of the stent.

Figure 2 shows in detail a portion of the lumen expanding stent according to the first embodiment of the present invention shown in FIG. The zigzag portion I located at the top of the stent includes a plurality of straight portions 100, and a peak portion 102 connecting the straight portions 100 (the term peak used herein is referred to as the length of the stent). Means a portion projecting outward) and the valley portion 104 (the term valley portion used herein means a portion projecting in the longitudinal direction of the stent), such a straight portion 100, Peak portion 102 and valley portion 104 form one band (A, B or C). In the illustrated embodiment, the zigzag portions I and III located at the upper and lower ends of the stent each consist of three bands, but are not limited thereto.

Consecutive bands (A, B, C) are connected by a twisted coupling between the valleys of the band located at the top and the peaks of the band located at the bottom. Thus, the valley has a substantially straight shape to facilitate this connection and to prevent shape deformation during expansion and contraction of the stent.

Referring to FIG. 2, in the valley portion 104 of the lowermost band C of the zigzag portion I located at the top of the stent, the filaments 114 constituting the spiral portion II located at the center are twisted, respectively. Is connected. The helical portion (II) is a zigzag portion (III) in which the filament 112 extending from the last peak portion 102L of the lowermost band C of the zigzag-shaped portion (I) located at the upper end of the stent is located at the lower end. The other valleys of the lowermost band (C) of the zigzag-shaped part (I), which are twisted in the valley of the uppermost band of the term (the term used herein, means upward in FIG. The pattern connected in a twisted manner to 104 is repeatedly formed. The filaments 114 forming the helical portion II cross each other in an unbonded state.

According to one feature of the present application, because a single length of filament is used, the lumen expanding stent has only two ends 108 connected to a band of zigzag portions located at the upper and lower ends. Therefore, even if a load is applied to the stent in the circumferential direction, the shape thereof is not easily disturbed, and the tissue of the lumen is not damaged when or after being placed inside the lumen.

The filaments forming the first band A form a plurality of peaks 102 and valleys 104 along the circumferential direction of the first band. The filament 106 forming the last peak portion 102L of the first band A extends downward to form the valley portion 104 'of the second band B, so that the circumference of the second band B is A plurality of peaks 102 'and valleys 104' are formed along the direction. At this time, as described above, the peak portion 102 ′ of the second band B is connected to the valley portion 104 of the first band A in a twisted manner.

The filament 126 forming the last peak portion 102 ′ L of the second band B extends downward to form the valley portion 104 of the third band C, so that the third band C A plurality of peaks 102 and valleys 104 are formed along the circumferential direction.

In addition, the filament 112 forming the last peak portion 102L of the third band C is connected in a twisted manner to the uppermost valley portion of the zigzag portion III located at the bottom of the stent. Of course, according to the manufacturing method of the stent of the present invention, the upper zigzag portion is manufactured, and after the central spiral portion is manufactured, the lower zigzag portion is manufactured.

In the filament forming the helical portion II, the filament 114 facing the bottom of the stent and the filament 115 facing the top extend in opposite directions. When the filaments 114 and 115 are wound spirally along the circumferential direction of the stent, a plurality of meshes are formed by intersection points between the filaments.

Of these spirally wound filaments, the final filament 116 extends toward the bottom via the adjacent valley 104 after being twisted in the valley 104 of the band C. The downwardly extending filament 118 is used to form the lower zigzag portion III.

The starting end 108 of the filament forming the first band A is twistedly connected to the fixed filament at a predetermined point. In the illustrated embodiment, the starting end 108 is twisted and finished with the filament extensions of the first and second bands, but is not limited thereto.

Although the upper end of the lumen expanding stent has been described in detail with reference to FIG. 2, the zigzag part III located at the bottom of the stent also has the same shape and structure as the zigzag part I described above. Therefore, the additional description thereof will be omitted.

The material of the filament used in the above-described lumen expanding stent is well known in the art.

Although several materials have been proposed, including 49-58% (atomic) Ni-Ti alloys, Ni-Ti, which transitions between austenite and martensite at 10 ° C or below, is complete. Alloys are preferred. In the non-stress state at room temperature, these superelastic alloys are present as austenite crystal phases, and show stress-induced austenite-martensite crystal transitions which, under stress, cause nonlinear elasticity.

Also known are stents made of shape memory alloys, such as nickel-titanium alloys known as nitinol. This stent restores its original shape when warmed by body temperature.

Although not shown separately in the drawings, it may be wrapped with a polymer or other material to prevent the cells from proliferating through the mesh structure of the stent. Such materials should not adversely affect the stent's flexibility and resilience.

In an embodiment of the present invention, both ends of the stent have a zig-zag-shaped portion composed of a plurality of bands coupled in a twisted manner, so the flexibility is weak but the resilience is very excellent. In addition, since the helical portion disposed at the center is arranged so that the filaments are not bonded to each other, the restoring force is weak, but the flexibility is excellent.

Hereinafter, the lumen expanding stent according to the second embodiment of the present invention will be described with reference to FIG. 3.

The lumen expanding stent shown in FIG. 3 is except that the zigzag-shaped portions I 'and III' formed at both ends have a flare shape in which diameters are expanded toward the ends to prevent the stent from moving. It is substantially similar to the embodiment shown in FIG. 1 and FIG. 2.

When the flare-shaped zigzag portions I 'and III' are positioned left and right about the lesion site, the stent is prevented from sliding left and right by the flare portion. In addition, even if disposed in the bent lumen, the helical portion formed in the central portion of the stent can not only be sufficiently bent, but also has the advantage that the restoring force is maintained by the zigzag portions I 'and III' provided at both ends. In addition, since both ends are expanded in the form of flares, the tendency of the stent to escape from the curved lumen is prevented.

In addition, Figure 4 shows a lumen expanding stent according to a third embodiment of the present invention. In the lumen expanding stent of this embodiment, zigzag portions I and III having uniform diameters are formed at both ends in order to more reliably prevent slipping in the lumen than in the embodiment shown in FIG.

Referring to FIG. 5, there is shown a lumen expanding stent in accordance with a fourth embodiment of the present invention formed entirely in a zigzag portion. Both ends of this embodiment have flare-shaped diameter enlarged portions whose diameters are enlarged toward the ends to prevent sliding.

FIG. 6 also shows a fifth embodiment according to the invention which is substantially the same as the embodiment shown in FIG. 5 except for both ends having a uniform diameter enlargement.

Since the zigzag portion of the stent shown in FIGS. 5 and 6 is substantially the same as the zigzag portion shown in FIG. 2, the description thereof will be omitted.

Referring to FIG. 7, there is shown a lumen expanding stent in accordance with a sixth embodiment of the present invention formed entirely in a helical portion.

The filament is wound in a first spiral direction from the first point of the upper end of the stent to the first point of the lower end, and is bent at the first point of the lower end to the second point of the upper end of the stent in a direction opposite to the first spiral direction. It is wound in a spiral direction. It is preferable that the primary spiral direction and the secondary spiral direction substantially form a supplementary angle. This is because the filaments must extend in both directions in a complementary relationship at the same bending point so that the helical portion of the stent can be formed uniformly. When this spiral winding is repeated several times along the circumferential direction, the filaments wound in the primary spiral direction and the secondary spiral direction cross each other to form a plurality of meshes.

In order to prevent the stent from sliding in the lumen, both ends of the stent have a flare shape in which a diameter thereof is enlarged toward the end.

8 shows a seventh embodiment according to the invention which is substantially the same as the embodiment shown in FIG. 7 except that both ends of the stent have a diameter enlargement.

As described above, according to the first to third embodiments of the present invention, the lumen expanding stent has a zig-zag portion at both ends and a spiral portion at the center thereof, so that the advantages of the zig-zag portion with excellent restoring force are provided. And all of the advantages of the helical part having excellent flexibility. Therefore, the stent according to the present invention can be maintained in the center of the center because the restoring force is maintained by the zigzag portion formed at both ends, even if the stent is disposed in the lumen by means such as a catheter. In addition, because the lumen expanding stent is composed of a single length of filament, it is disposed inside the lumen, and its shape is not disturbed after expansion.

In addition, the above-described lumen expanding stent has an enlarged diameter of the end portions of the zigzag-shaped portion or the helical portion, so that it is prevented from being separated from a predetermined portion in the lumen.

Claims (10)

A cylindrical lumen expanding stent consisting of a single length of filament, Zigzag-shaped portion in which the filaments are wound in a zigzag form at both ends of the stent, Located between the zigzag portions, wherein the filaments comprise a spiral portion in which the filaments are spiral wound; The zigzag portion has a straight portion, a peak portion and a valley portion, and forms a band disposed in the circumferential direction of the stent, and a lower band adjacent to the valley portion of the zigzag portion forming a band located at the end of the stent. The zigzag-shaped peak parts forming the zigzag are connected in a twisted manner, And the helical portion is twistedly connected with the valley of the lowermost band of the zigzag portion of the upper end of the stent and the valley of the zigzag portion forming the uppermost band of the lower end of the stent. 2. The lumen expansion stent of claim 1, wherein an additional zig-zag portion is disposed between the spiral portions. The stent for expanding lumen according to claim 1, wherein the upper and lower zigzag portions have a flare shape in which diameter is enlarged toward the distal end to prevent sliding of the stent. The stent for expanding lumen of claim 1 wherein the top and bottom zigzag portions have a diameter greater than the diameter of the helical portion. The stent for lumen expansion according to any one of claims 1 to 4, wherein the filament is made of a nickel-titanium alloy. 5. The lumen expanding stent of claim 1, wherein the stent is wrapped with a suitable material that does not adversely affect flexibility and resilience. 6. A cylindrical lumen expanding stent consisting of a single length of filament, The stent includes a plurality of bands consisting of a portion in which the filament is wound in a zigzag shape, The zigzag portion has a peak portion and a valley portion, the peak is connected in a twisted manner with the valley portion of the adjacent upper zigzag portion, the valley portion is connected in a twisted manner with the peak portion of the adjacent zigzag portion , In order to prevent the stent from sliding in the lumen, both end portions of a predetermined length is formed in the flare shape is expanded in the flare shape toward the end. A cylindrical lumen expanding stent consisting of a single length of filament, The stent includes a plurality of bands consisting of a portion in which the filament is wound in a zigzag shape, The zigzag portion has a peak portion and a valley portion, the peak is connected in a twisted manner with the valley portion of the adjacent upper zigzag portion, the valley portion is connected in a twisted manner with the peak portion of the adjacent zigzag portion , In order to prevent the stent from sliding in the lumen, both ends of the predetermined length has a larger diameter than the central portion of the lumen expanding stent. A cylindrical lumen expanding stent consisting of a single length of filament, The filament is wound in a first spiral direction from the first point of the upper end of the stent to the first point of the lower end, and is bent from the first point of the lower end to the second point of the upper end of the stent in a direction opposite to the first spiral direction. Winding in the direction, This spiral winding is repeated in the circumferential direction to the last point of the upper and lower ends, and the filaments wound in the primary and secondary spiral directions cross each other to form a plurality of meshes, In order to prevent the stent from sliding in the lumen, the end portion of the predetermined length is characterized in that the luminal expansion stent is formed in a flare shape that is enlarged toward the distal end. A cylindrical lumen expanding stent consisting of a single length of filament, The filament is wound in a first spiral direction from the first point of the upper end of the stent to the first point of the lower end, and is bent from the first point of the lower end to the second point of the upper end of the stent in a direction opposite to the first spiral direction. Winding in the direction, This spiral winding is repeated in the circumferential direction to the last point of the upper part and the last point of the lower part, and the filaments wound in the primary spiral direction and the secondary spiral direction cross each other to form a plurality of meshes, In order to prevent the stent from sliding in the lumen, the end portion of the predetermined length has a larger diameter than the central portion of the lumen expanding stent.