JPH08196643A - Cavity organ treatment apparatus - Google Patents

Abstract

PURPOSE: To provide a device which effectively prevent stricture of a live cavity organ. CONSTITUTION: A cavity organ treatment tool comprises a flexible cylindrical cover member 1 and a stent member 2 which is arranged in the cylindrical cover member, is convertible from the first small-diameter shape to the second large-diameter shape, and is relatively hard. And the cylindrical cover member 1 and the stent member 2 are formed from an organic adsorption material and at least an outer surface of the cylindrical cover member 1 has porosity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow organ treatment instrument which is inserted into a hollow organ in a living body such as a blood vessel or a bile duct to prevent narrowing or rupture.

[0002]

2. Description of the Related Art Stents have come to be used to prevent restenosis after expanding a narrowed hollow organ with a balloon catheter or the like. The stent currently used is an assembly of metal wires, and it is first folded to have a small diameter, and when it reaches the target site of the hollow organ, it is expanded and brought into close contact with the inner wall of the hollow organ. It prevents squeezing.

Although such a metal stent has some effect in preventing stenosis, it tends to give stress to a hollow organ, so that it causes inflammation or excessive thickening which causes restenosis. I know that there is. Also,
There is also a problem that metal permanently remains as a foreign substance in the living body. Therefore, recently, a stent made of a synthetic resin has been studied, and in particular, various stents using a bioabsorbable synthetic resin have been proposed. As such examples, there are JP-A-3-205059, JP-A-5-103830, and JP-A-5-509008.

On the other hand, Japanese Patent Publication No. 6-93920 discloses that
In order to solve the problems of the metallic stent, it has been proposed to mount a flexible sleeve on the outer side of the metallic stent.

[0005]

Although the above-mentioned improvements for solving the drawbacks of the metal stent have some effects, they are still insufficient in terms of preventing restenosis. An object of the present invention is to provide a device capable of effectively preventing restenosis of a hollow organ.

[0006]

SUMMARY OF THE INVENTION The device of the present invention comprises a flexible tubular cover member, and a tubular tubular cover member disposed within the tubular tubular cover member.
It is composed of a relatively hard stent member that is capable of transitioning from a small-diameter first shape to a large-diameter second shape. And
Both the tubular cover member and the stent member are made of a bioabsorbable material, and at least the outer surface of the tubular cover member is porous. In particular, it is important that at least the outer surface of the tubular cover member is made porous so that restenosis can be effectively prevented.

[0007]

According to the device of the present invention, the tubular cover member and the stent member are inserted into the hollow organ in a state where the diameter thereof is small, and the stent member is changed to the second shape having the large diameter at a target site to form the tubular cover. The hollow organ is held from the inside so that the member adheres to the inner wall of the hollow organ to prevent squeezing.

In the present invention, since the stent member is made of a relatively hard material, it is possible to sufficiently secure the restoring force to the second shape having the large diameter. Since the hard member does not come into direct contact with the living body by covering it with the flexible tubular cover member, stress on the living body is small.
In addition, since at least the outer surface of the cylindrical cover member is made porous, the living tissue invades the pores and is integrated with the tissue, so that squeezing can be effectively prevented. Furthermore, since the whole body is made of the bioabsorbable material, it is eventually absorbed by the living body and disappears, and does not remain as a foreign substance permanently like metal.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described more specifically below with reference to the drawings. FIG. 1 shows one embodiment of the hollow organ treatment device of the present invention. In the figure, 1 is a tubular cover member, and 2 is a stent member. In this example,
The stent member is made of a shape-memory material, and is initially stretched to have a small diameter, and after being inserted into the hollow organ, it is heated at body temperature and restored to the large diameter shape on the right side.

FIG. 3 shows another embodiment of the stent member.
In this example, the shape is initially a folded cylinder, which restores the original cylindrical shape. FIG. 4 shows still another embodiment, in which the rolled shape of the sheet is restored to the cylindrical shape.

Further, the stent member may be one in which the second shape is elastically compressed to have a small diameter. Particularly, as disclosed in Japanese Patent Publication No. 4-32662, a linear member formed in a closed loop having a zigzag structure and elastically compressed can be preferably used.

The outer surface of the cylindrical cover member needs to be porous, but the entire cover member may be porous, or the outer surface is porous and the inner surface is non-porous. It may be a structure. The pore size is preferably a size suitable for invasion of biological tissue, about 10 to 200 μm is suitable, and 20 to 100 μm is particularly preferable. As a method for producing a porous material, after mixing solid particles of a predetermined particle size with a polymer raw material and molding, the particles are dissolved, but the polymer is immersed in a solvent that does not dissolve,
A method of removing solid particles is suitable. As the solid particles, sodium chloride or calcium carbonate is preferable. In the case of sodium chloride, water or an aqueous solution is preferable, and in the case of calcium carbonate, an acid aqueous solution such as hydrochloric acid or nitric acid is preferable. A woven fabric or a knitted fabric can also be used as the porous material, but the porous body obtained by the above-described method is preferable in that a porous body having a desired pore size can be constantly manufactured.

In the present invention, as shown in FIG. 1, the stent member may be housed inside the tubular cover member, or may be embedded in the tubular cover member to form an integrated structure. .

Both the stent member and the tubular cover member are made of a bioabsorbable material. Examples of such a material include polyglycolic acid, polylactic acid, lactic acid-glycolic acid copolymer,
Examples thereof include lactic acid-ε caprolactone copolymer, lactic acid-glycolic acid-ε caprolactone copolymer, hydroxybutyric acid-hydroxyvaleric acid copolymer, polydioxanone, polyglyconate and chitin.

Among these, as the stent member,
Polyglycolic acid, polylactic acid, and a lactic acid-glycolic acid copolymer are preferable in that shape memory can be imparted. That is, when a molded article made of these polymers is deformed at a predetermined temperature or lower (usually 30 to 40 ° C. or lower, preferably room temperature or lower), JP-A-1-
As disclosed in Japanese Patent No. 192367, it has a shape memory property. Therefore, if a molded product having a second shape as shown in FIGS. 2 to 4 is prepared and deformed into the first shape, it can be suitably used as the stent member in the present invention. Among the above-mentioned polymers, a lactic acid-glycolic acid copolymer having a lactic acid copolymerization ratio of 70 to 90% by weight is particularly preferable because it can be restored at a temperature of about body temperature.

The tubular cover member is preferably made of a material that is more flexible than the stent member. Specific examples of suitable materials include lactic acid-glycolic acid copolymers, lactic acid-ε caprolactone copolymers, lactic acid-glycolic acid-ε caprolactone copolymers, polydioxanone and polyglyconates.

The device for treating hollow organs of the present invention can be used for preventing stenosis of blood vessels, bile ducts, ureters and the like. A catheter is generally used to bring the device of the present invention to a predetermined portion of a hollow organ that requires squeezing prevention. That is, the device of the present invention is housed in the distal end portion of the catheter, inserted into the hollow organ, and released from the catheter at a predetermined position to expand the diameter.

The device of the present invention can also be used for treatment to prevent rupture of an aneurysm. That is, if the device of the present invention is inserted into a place where an aneurysm is present and the tubular cover member is brought into close contact with the inner wall of the blood vessel, the blood vessel wall is reinforced by the tubular cover member, and the intravascular pressure is directly applied to the aneurysm. Since it does not work, the risk of rupture is reduced.

[0019]

In the device for treating hollow organs of the present invention, since the stent member is covered with the flexible tubular cover member, stress on the hollow organ is small, and inflammation and excessive thickening hardly occur. Further, since the stent member is formed of a hard material, the diameter expansion to the second shape is performed with a sufficient force. Since at least the outer surface of the cylindrical cover member is porous, biological tissue such as endothelial cells and fibroblasts invades and is integrated with the cover member, effectively squeezing the hollow organ for a predetermined period. Can be prevented. Although it is not clear why the porous material has an excellent anti-squeezing effect, it is presumed that the biocompatibility is enhanced by the invasion of the biological tissue. Furthermore, since the entire device is made of bioabsorbable material,
The problem of being decomposed and absorbed by the living body and remaining in the living body as a foreign substance does not occur. Then, finally, the biological tissue that has penetrated into the hole is replaced with the tubular cover member to become only the biological tissue, and the biological repair is completed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a hollow organ treatment instrument of the present invention.

FIG. 2 is a perspective view showing an embodiment of a stent member used in the present invention.

FIG. 3 is a perspective view showing another embodiment of the stent member used in the present invention.

FIG. 4 is a perspective view showing still another embodiment of the stent member used in the present invention.

[Explanation of symbols]

 1 Cylindrical cover member 2 Stent member

Claims (7)

[Claims] 1. A flexible tubular cover member and a first shape having a small diameter to a second diameter having a large diameter, which is disposed in the tubular cover member.
A device for treating a hollow organ comprising a relatively hard stent member that can be transformed into the shape of FIG. 1, wherein both the tubular cover member and the stent member are made of a bioabsorbable material, and the tubular cover A hollow organ treatment device characterized in that at least the outer surface of the member is porous. 2. The hollow organ treatment instrument according to claim 1, wherein the stent member is housed inside a tubular cover member. 3. The hollow organ treatment instrument according to claim 1, wherein the stent member is embedded in a tubular cover member. 4. The hollow organ treatment device according to claim 1, wherein the stent member is made of a homopolymer of lactic acid or glycolic acid or a copolymer thereof. 5. The hollow organ treatment instrument according to claim 1, wherein the stent member has a shape memory property. 6. The hollow organ treatment instrument according to claim 1, wherein the entire tubular cover member is porous. 7. The hollow organ treatment device according to claim 1, wherein the tubular cover member is formed of a copolymer of lactic acid and glycolic acid or a copolymer of lactic acid and ε-caprolactone. .