CN219126899U

CN219126899U - Stent for treatment of luminal stenosis

Info

Publication number: CN219126899U
Application number: CN202223002783.6U
Authority: CN
Inventors: 王伟; 樊超强; 邢孟秋; 杨仕明
Original assignee: Second Affiliated Hospital Army Medical University
Current assignee: Second Affiliated Hospital Army Medical University
Priority date: 2022-11-09
Filing date: 2022-11-09
Publication date: 2023-06-06
Anticipated expiration: 2032-11-09

Abstract

The utility model discloses a bracket for treating lumen stenosis, which comprises a supporting part made of shape memory materials, wherein the supporting part is integrally tubular, and can be expanded to a supporting state under the condition stimulation after being implanted into a lumen of a human or animal body, so as to provide circumferential support for the lumen, and the supporting part is formed by extending and shaping strips of high polymer materials along a spiral line; the width w and the thickness t of the strip satisfy the relation w>2t; the axis of the strip on the supporting partDimension in line direction d ₁ A helical pitch of d ₂ ，d ₁ And d ₂ Satisfy the relation of 0.3d ₂ ≤d ₁ ≤d ₂ . The beneficial effects of the utility model are as follows: can meet the requirements of mechanical properties, particularly radial supporting performance and deformation recovery of the stent, has good compliance and reduces the ingrowth of the tissue on the inner wall of the lumen.

Description

Stent for treatment of luminal stenosis

Technical Field

The utility model relates to the technical field of medical instruments, in particular to an implantation instrument, and particularly relates to a bracket for treating lumen stenosis.

Background

With the development of imaging, interventional medicine and material science, stent implantation is becoming an effective means for treating various lumen stenosis or obstruction in the human body. After the stent is placed in the lesion pipeline, the pipe wall is circumferentially spread so as to ensure that the pipe cavity is smooth. The most commonly used stents in clinic are vascular stents, biliary stents, esophageal stents and respiratory stents. Conventional stents rely on balloon-like devices as delivery and expansion devices that support the lumen wall by expanding the stent with pressure after delivery to the target site, and implantation is relatively complex. In recent years, stents made of shape memory materials have been used, which have the characteristic of being capable of automatically deforming under stimulation after being delivered into a lumen due to environmental responsiveness, thereby expanding the canal, which greatly simplifies the implantation procedure. Most shape memory stents are woven by wire-like metallic ribs with high strength in a net shape, the contact area between the ribs and the lumen wall is small, local damage is easy to cause, and lumen wall tissues can grow in from holes in the stent wall to cause secondary stenosis. Thus, there is a need for improved structural designs for stents that compromise both shape memory and support properties.

Disclosure of Invention

In view of this, the present utility model provides a stent for treating luminal stenosis.

In order to achieve the above purpose, the technical scheme of the utility model is as follows:

the support for treating lumen stenosis includes one support part of shape memory material, which is tubular and can expand to support after being implanted into the lumen of human or animal body to provide circumferential support for the lumen, and features that the support part is formed with polymer material strips extending along spiral line and setting;

the relation w >2t is satisfied between the width w and the thickness t of the strip.

Preferably, the dimension of the strip in the axial direction of the support portion is d ₁ A helical pitch of d ₂ ，d ₁ And d ₂ Satisfy the relation of 0.3d ₂ ≤d ₁ ≤d ₂ 。

Preferably, the support portion has a spiral pitch d ₂ 1 to 1.5 times the width w of the strip, i.e. d ₂ ＝w*(1～1.5)。

Preferably, the thickness of the strip is 0.2-0.5 mm, and the width is 3-6 mm; the diameter of the supporting part is 2.6-3.2 mm, and the length is 4-10 cm.

Preferably, the outer wall of the support portion is provided with a diversion trench.

Preferably, the guide groove extends in a spiral shape along a winding direction of the strip.

Preferably, two edges of the strip corresponding to one surface of the outer side of the supporting part are respectively provided with an upward strip-shaped bulge, the bulge extends along the edge of the strip, and after the strip is wound into the supporting part, two bulges and the outer side of the strip enclose the diversion trench;

the height of the bulge is 0.1-0.5 mm.

Preferably, at least one end of the supporting portion is further connected with an annular positioning portion, an inner hole of the positioning portion is communicated with the inner cavity of the supporting portion, and an anti-displacement structure is arranged on the positioning portion.

Preferably, the above-mentioned anti-displacement structure is a barb, the tail end of the barb is fixedly connected with the positioning portion, and the front end of the barb extends radially outwards and towards the direction of the supporting portion.

Preferably, the positioning portion and the supporting portion are made of the same biodegradable polymer material;

the positioning portion is loaded with an X-ray developing substance, or the positioning portion and the supporting portion are both loaded with an X-ray developing substance.

The beneficial effects of the utility model are as follows:

(1) Meets the requirements of mechanical properties, particularly radial supporting properties, of the bracket;

(2) The spiral design is convenient for shaping the whole supporting part, and the part of the supporting part is restored to deform towards the original shape direction of the strip under the condition stimulation so as to be self-expanding, so that the supporting part also has certain axial bending deformation capacity and keeps good compliance;

(3) The ratio of the void area of the outer wall of the supporting part is smaller than that of a traditional metal spring-shaped bracket, and the contact area between the outer wall of the supporting part and the lumen wall is larger in the same length, so that the ingrowth of tissue on the inner wall of the lumen is prevented, and the secondary stenosis of the lumen is reduced.

Drawings

FIG. 1 is a schematic diagram of the structure of the present utility model;

fig. 2 is a schematic structural view of a screw unit of the support part;

fig. 3 is a schematic cross-sectional view of a strip for molding a support.

Detailed Description

The utility model is further described below with reference to examples and figures.

As shown in fig. 1 to 3, a stent for treating lumen stenosis comprises a support portion 1 made of a shape memory material, the support portion 1 being generally tubular in shape, the support portion 1 being capable of expanding to a supported state upon conditional stimulation after implantation into a lumen of a human or animal body, thereby providing circumferential support for the lumen to distract the stenosed lumen. The supporting portion 1 of the present embodiment is formed by extending and shaping a strip of a polymer material along a spiral line, and thus the supporting portion 1 has a tendency to recover to the original strip shape after being subjected to a conditional stimulus, thereby self-expanding in a manner of unwinding the spiral line and increasing in diameter. The shape memory material is preferably a material that is deformed and recovered under the action of temperature, light or a solvent, for example, a material that is deformed and recovered under the action of body fluid. The conventional spiral bracket is made of a metal material with higher strength, so that the ribs of the conventional spiral bracket are smaller in size, and different in the embodiment. Since the strength of the polymer material is generally lower than that of the metal material, but the requirements of deformation recovery and pipe wall support must be met, the size design is that: the relation w >2t, more preferably w >4t, is satisfied between the width w and the thickness t of the strip.

To further increase the supporting force, the dimension of the strip in the axial direction of the supporting portion 1 is d ₁ A helical pitch of d ₂ ，d ₁ And d ₂ Satisfy the relation of 0.3d ₂ ≤d ₁ ≤d ₂ 。

By adopting the design, the requirements of the mechanical property of the bracket, particularly the radial supporting property, are met; meanwhile, the spiral design is convenient for the whole support part to be shaped and deformed to recover, so that the support part has certain axial bending deformation capacity and keeps good compliance; in addition, the ratio of the void area of the outer wall of the supporting part 1 is smaller than that of a common spring type bracket, the contact area between the outer wall of the supporting part 1 and the lumen wall is larger in the same length, the stress concentration degree is smaller, and meanwhile, the ingrowth of the tissue of the lumen inner wall is prevented.

In one embodiment, the helical pitch d of the support 1 ₂ 1 to 1.5 times the width w of the strip, i.e. d ₂ =w (1 to 1.5). The pitch of the spiral is referred to herein as the distance traveled in the axial direction after one point on the spiral has been wound around. The relatively dense spiral arrangement mode can provide a large supporting force for the lumen, which is close to that of the complete tubular stent; meanwhile, due to the fact that the single strip is adopted for winding and forming, each spiral section of the supporting portion 1 is easy to deform synchronously when being stressed, and the supporting portion has better performance particularly in the processes of shaping and stimulated expansion.

In one embodiment, the stent is used as a biliary stent, so that the diameter of the supporting part 1 is 2.6-3.2 mm, the length is 4-10 cm, and the diameter can reach 5-6 mm after implantation into biliary tract and self-expansion. The thickness of the strip is 0.2-0.5 mm, and the width is 3-6 mm.

In one embodiment, the outer wall of the supporting part 1 is provided with a diversion trench 1a, and the liquid flowing into the space between the outer wall of the supporting part 1 and the inner wall of the lumen can flow along the diversion trench 1a, so that the liquid in the lumen is prevented from being deposited and solid components are prevented from being deposited and accumulated. In particular, when used as a biliary stent, this design can avoid bile from collecting between the outer wall of the stent and the lumen wall. Further, the existence of the diversion trench 1a makes the outer wall of the supporting portion 1 not a smooth surface but have a concave-convex shape. This topography helps to increase the friction between the stent and the lumen wall after implantation, helping to position the stent.

In one design, the channel 1a extends along a spiral of the support 1.

The strip can be molded in a mold by pouring a polymer solution, and the strip is uniformly wound on a steel rod under a plastic condition such as a preliminary molding state of the strip, and the support part 1 is obtained after molding.

When the ribbon is used for other parts such as intestinal tracts and blood vessels, the size of the ribbon and the wound spiral size can be adjusted according to the needs so as to obtain the most suitable effect.

As shown in fig. 3, two edges of the strip corresponding to one surface of the outer side of the supporting portion 1 are respectively provided with an upward strip-shaped protrusion 1b, the protrusion 1b extends along the edge of the strip, and after the strip is wound into the supporting portion 1, two protrusions 1b and the outer side surface of the strip enclose the diversion trench 1a. In this embodiment, the height of the protrusion 1b is 0.1 to 0.5mm. The bulge 1b can increase the friction force between the surface of the stent and the wall of the lumen, and can also enhance the rigidity of the stent and improve the radial compressive resistance.

As shown in fig. 1, in order to further improve the positioning effect of the bracket in the pipeline, at least one end of the supporting portion 1 is further connected with an annular positioning portion 2, an inner hole of the positioning portion 2 is communicated with an inner cavity of the supporting portion 1, and an anti-displacement structure is arranged on the positioning portion 2.

In one embodiment, the anti-displacement structure is a barb 2a, the tail end of the barb 2a is fixedly connected with the positioning portion 2, and the front end of the barb extends radially outwards and towards the supporting portion 1. The barbs 2a may be partially cut by the positioning portions 2 and bent outwardly. The anti-displacement structure may also utilize other structures common in existing stents, such as barbs.

In order to facilitate the molding and maintain the degradation rate substantially uniform, the positioning portion 2 and the supporting portion 1 are made of the same polymer material. The outer diameter of the positioning part 2 is not larger than the outer diameter of the supporting part 1 in a natural state. After the positioning part 2 and the supporting part 1 can be respectively molded, the joint is bonded and fused by using a high polymer solution as an adhesive, and the bracket with the positioning part 2 is obtained after drying and curing. In addition, the strips with the positioning parts 2 at the two ends respectively can be integrally formed in a die casting forming mode, and then the middle strip is wound to form the supporting part 1.

For the convenience of implantation observation and post-operation detection, the positioning part 2 is loaded with an X-ray developing substance, or the positioning part 2 and the supporting part 1 are both loaded with an X-ray developing substance. The X-ray developing substance can be dispersed in the macromolecule solution in advance, and the bracket is loaded on the bracket after the bracket is molded.

Preferably, the support 1 is made of a biodegradable polymer, preferably poly (3-hydroxybutyrate-co-4-hydroxybutyrate), i.e., P (3 HB-co-4 HB). The mole fraction of the monomer 4-hydroxybutyrate in the copolymer is 1-50%. P (3 HB-co-4 HB) has a weight average molecular weight of 10 ten thousand to 100 ten thousand, is produced by copper species of the order of magnitude of crochet hook under the conditions of sufficient carbon source and lack of nitrogen source, and has a shape memory function in PBS, bile and acetone. After the stent made of the material is implanted into biliary tract, the stent has a tendency of shape recovery under the action of bile, so that the stent is self-expanding.

When used in the lumen of the alimentary canal, the stent can be placed and released through an endoscope and slowly and gradually degraded, providing sufficient support time for the lumen to be shaped and eliminating the need for secondary surgical removal.

Finally, it should be noted that the above description is only a preferred embodiment of the present utility model, and that many similar changes can be made by those skilled in the art without departing from the spirit and scope of the utility model as defined in the appended claims.

Claims

1. A stent for the treatment of luminal stenosis, comprising a support portion (1) made of a shape memory material, the support portion (1) being generally tubular, the support portion (1) being capable of expanding to a supporting state upon conditional stimulation after implantation in a lumen of a human or animal body, thereby providing circumferential support for the lumen, characterized in that: the supporting part (1) is formed by extending and shaping strips of high polymer materials along a spiral line;

2. The stent for treating luminal stenosis of claim 1, wherein: the dimension of the strip in the axial direction of the support part (1) is d ₁ A helical pitch of d ₂ ，d ₁ And d ₂ Satisfy the relation of 0.3d ₂ ≤d ₁ ≤d ₂ 。

3. The stent for treating luminal stenosis of claim 1, wherein: the helical pitch d of the support part (1) ₂ 1 to 1.5 times the width w of the strip, i.e. d ₂ ＝w*(1～1.5)。

4. The stent for treating luminal stenosis of claim 2, wherein: the thickness of the strip is 0.2-0.5 mm, and the width is 3-6 mm; the diameter of the supporting part (1) is 2.6-3.2 mm, and the length is 4-10 cm.

5. A stent for treating luminal stenosis as in any of claims 1-4 wherein: the outer wall of the supporting part (1) is provided with a diversion trench (1 a).

6. The stent for treating luminal stenosis of claim 5, wherein: the diversion trench (1 a) extends spirally along the winding direction of the strip.

7. The stent for treating luminal stenosis of claim 5, wherein: two edges of one surface of the strip, which corresponds to the outer side of the supporting part (1), are respectively provided with an upward strip-shaped bulge (1 b), the bulge (1 b) extends along the edge of the strip, and after the strip is wound into the supporting part (1), the two bulges (1 b) and the outer side of the strip form the diversion trench (1 a);

the height of the bulge (1 b) is 0.1-0.5 mm.

8. A stent for treating luminal stenosis as in any of claims 1-4 wherein: at least one end of the supporting part (1) is also connected with an annular positioning part (2), an inner hole of the positioning part (2) is communicated with an inner cavity of the supporting part (1), and an anti-displacement structure is arranged on the positioning part (2).

9. The stent for treating luminal stenosis of claim 8, wherein: the anti-displacement structure is a barb (2 a), the tail end of the barb (2 a) is fixedly connected with the positioning part (2), and the front end of the barb extends outwards in the radial direction and extends towards the supporting part (1).

10. The stent for treating luminal stenosis of claim 8, wherein: the positioning part (2) and the supporting part (1) are made of the same biodegradable high polymer material;

the X-ray developing substance is loaded on the positioning part (2) or on both the positioning part (2) and the supporting part (1).