KR100445390B1 - Surgical Graft / Stent System - Google Patents

Abstract

The tubular graft / stent has a tubular sheath 10 with a plurality of ring rigid members 11 spaced along the length, the member 11 attached to the sheath around each circumference and having a shape memory. Since it is formed of a material, when the shape of the member changes, the sheath 10 takes a new cross section corresponding to the member along its entire length. The rigid member is a discontinuous state and takes a compressed shape on martensite and an enlarged shape on austenite. The transplanted tissue may also have side tubes 14 that can be reversed to be received within the sheath.

Description

Surgical Graft / Stent System

A graft / stent system for use in human or animal surgical operations.

One example of this type of graft is an artificial blood vessel in the form of a tubular sheath having a ring-shaped member disposed at each end, which is disclosed in EP 0326426A. Another example is an aortic graft with two branched tubular ends, disclosed in EP 0461791A.

1 is a perspective view showing a graft of a first form,

2 is a cross-sectional view showing the compressed form on martensite;

3 is a view showing an enlarged form of an austenite phase;

4 shows an embodiment with a branch tube in an inverted position, FIG.

5 shows a variant of FIG. 4 with an expanded branch tube, FIG.

6 is a view showing another embodiment of the present invention;

7 and 8 are enlarged exploded views of two modifications of the overlap region.

<Description of the symbols in the main part of the drawing>

10: tubular sheath 11: rigid member

14: Branch tube

According to one aspect of the invention, there is provided a tubular graft / stent according to claim 1.

According to another aspect of the present invention, there is provided a tubular graft / stent according to claim 9.

The present invention proposes a medical tubular graft / stent having a tubular sheath with a plurality of ring-shaped rigid members spaced apart along its length, the members being attached to the sheath around each circumference, Since it is made of a shape memory material, when the shape of the member changes, the sheath takes a new cross section corresponding to the member along the entire length.

Preferably, this provides a flexible tubular sheath composed of a series of open rings. The ring acts as a rigid member and can be compressed radially by the mechanical force on the martensite to reduce its diameter and then return to the large diameter austenite phase stored by thermal action.

In a further aspect of the invention, the invention is a tubular sheath having been reversed to be received within the sheath during the insertion operation in a human or animal body, the branch tube (branch tube) having a sufficient flexibility to be relocated as a branch to the surgery Provide a tubular graft having a. The sheath and / or branch tube can use an annular rigid member made of a shape memory material as described above. In all cases, the member is preferably in discrete form. An example is a ring with a brake to facilitate compression and re-expansion.

BRIEF DESCRIPTION OF THE DRAWINGS In order to clearly understand the present invention, several exemplary embodiments will now be described with reference to the accompanying drawings.

A typical conventional arrangement is shown in FIG. The flexible tubular sheath 10 can be made of any flexible material such as cloth, polymer, elastomer or gel. In the flexible tubular sheath a number of expandable or retractable opening rings 11 made of shape memory alloy material are fixed. The ring made of shape memory alloy serves as a structural support of the flexible tubular sheath and is oriented in the transverse direction with respect to the tube axis. The tube is circumferentially sealed by the overlap 20, but has a free edge. Alternatively, the free edges 21 and 22 may be adjacent to each other, but more certainly the tube wall is sealed.

The flexible tubular sheath 10 may be formed by a manufacturing method, or the "open" tube may be manufactured using a flat sheet whose shape is determined by a ring made of a shape memory alloy. The tubular form may also use sheets of different materials. The tube is made of continuous length and can be cut as needed.

The shape memory alloy ring can be retained by casting a suitable pliable material around the ring, or by forming a series of pockets in which the adhesive bonds, sews, or the ring can be received therein by welding, sewing, mechanical fastening or adhesive bonding. Can be. In the embodiment shown, the ring 11 consists of a single piece, but may consist of two or more arcuate parts.

2 and 3 show compressed (eg spiral or roll up) and enlarged forms of tubular sheaths . The tubular graft / stent is radially compressed with an outer diameter of 5.5 mm before the device is fitted to the human body by a delivery catheter. In an enlarged form, the outer diameter is 4 cm or less.

The devices described above are suitable for a number of minimally invasive surgeries or can actually reduce trauma associated with the introduction of implanted medical devices in vivo. As described above , a single tube of tubular sheath (known as a tubular graft ) with a swollen , expandable / shrinkable ring (known as a stent ) is inserted into a closed fluid-retaining vessel or a narrowing vessel. When moved to the proper position by the catheter, the potential geometry of the shape memory alloy will be reproduced due to heat from the human body (or introduced heating fluid). Under these circumstances, as shown in FIG. 3, the ring will expand to a predetermined position so that its outer dimension is slightly larger than the inner dimension of the fluid-bearing vessel. By the friction effect, the graft / stent will typically be held in place. However, the shape memory alloy may be arranged such that when the heat transfer point (memory reproduction) is reached, selected portions of the alloy protrude from the metal surface exhibiting substantial adhesion. One or more alloy rings may be formed to have these additional retention properties.

The device can be applied to surgical treatment or maintenance procedures of human or other animal species. Gastrointestinal connection, esophageal cancer, aneurysm, coronary bypass connection, and other vascular bypass or shunt procedures may utilize stent / graft devices.

The kinetic nature of the ring allows the graft / stent to expand in the body to open a compressed or closed vessel . The outer graft sheath may help prevent the occlusion material from entering the vasculature once more. The flexible sheath will also exclude tumor growth, keeping the aperture open.

The tubular graft having a ring of shape memory alloy made up of a simple tubular form as described above, or as shown in Figs. 4 and 5, the main tube 13 is composed of one or a number of branch tubes (14) It may be a manifold system provided . The fluid is passed into or out of the branch tube 14 by a single tube or manifold, or from or to the main tube structure. The branch tube extending from the body may have a uniform cross section or may have a tapering structure.

The tubular graft of the type described above may simply have a number of small or large tubes with similar structures attached to the main tube body or simply branched. Branches attached to the body of the device may have a similar shape memory alloy ring shape. Each branch tube 14 can be reversed upside down to fit into and fit into the main tube. Under this condition, the entire assembly can be compressed radially, where the manifold system looks like a single tube for initial insertion by the catheter. As shown in FIG. 5, the appropriate cord 15 is connected to an inverted branch, allowing retraction of the branch (s) by pulling the cord. Preferably, the ring closer to the main tube is largest and gradually smaller towards the end so that reversal can occur.

When warmed, the shape memory alloy ring will expand to a predetermined position. When used in surgical treatment, the force exerted by the ring of shape memory alloy is of sufficient magnitude so that the closed vasculature can be opened to allow the fluid to flow properly and continuously.

The flexible outer sheath may move the vasculature radially or axially. This may be the case when the stent / graft is placed in a radially esophagus. The peristalsis effect used to help transport food and body fluids in the human body will continue to be required in esophageal dysfunction problems. Covered or covered stent systems can rule out intratumoral growth and still cause peristalsis.

The flexible material may be 0.050 mm polyurethane, polyester or polytene. The shape memory material may be a metal alloy having such properties, or may be a specific moldable plastic material, such as a lactide or a homopolymer of glycolide, or a copolymer of lactide and glycolide.

The present invention also provides a graft with a branch tube that does not use a stent of shape memory material. Thus, in addition to the shape memory material, the ring-shaped rigid member 11 may be made of an elastic material such as stainless steel, or may be in a superelastic form made of nickel-titanium alloy. In this case, the graft is confined within the outer sheath and after removal of the outer sheath the graft will expand to take the final shape.

In the embodiment of FIG. 6, which is particularly desirable for stent meandering vessels, such as the male urethra, the flexible tubular sheath comprises a slit or opening 23 that is generally parallel to the ring-shaped member and that allows the graft to bend large without torsion of the sheath. can do. The arrangement of the slits or openings may vary depending on the application and may be located on one side of the tube 23, all on the alternating side 24, or helically arranged along the sheath 25. Other arrangements are possible.

The overlap 20 can be designed to have one of three characteristics.

1) The overlap can slide freely relative to itself so that the graft assembly can be contracted by the muscles in the vessel or the arterial blood pressure pulse due to heart rate to the arterial wall. The pressure pulse action is involved in maintaining the vasomotor state of the blood vessels.

Faces matching the overlap of the sheath can be covered with a material such as PTFE or diamond coating to reduce friction and wear.

2) As shown in FIG. 7, the overlap may have a ratchet-type mechanism in which the diameter of the ring-shaped rigid member is enlarged but does not shrink . This will keep the lumen of the vessel at the minimum diameter so that a ring that is secured to the interior of the vasculature wall will reliably prevent movement of the device.

3) As shown in Figure 8, the overlap would be to be able to include a ratchet-type mechanism, the diameter of the ring-shaped rigid member does not exceed a certain diameter. This is useful when the vessels are fragile and can be exposed to high pressure in the lumen.

The ratchet mechanism can be included in the wall of the sheath by molding, machining, or by attaching the ratchet component. In addition, the ratchet mechanism can be formed at the distal end of the ring-shaped member and can be permanently present or deployed by thermal memory action.

The graft incorporates a combination of all three overlapping mechanisms, such as by using a ratchet in which the distal end of the graft enlarges the ring, allowing the device to be held in place and the main body of the graft providing a sliding and diameter defining ring. Alternately, they can be assembled to deliver a limited pulse rate while limiting the maximum diameter of the graft .

Incorporation of the coating into its inner or outer surface can increase the benefits of the graft . Such coatings may be biomimetric such as phosphorylcholine and protein, organic biological affinity such as hydrophilic plastics and inorganic coatings such as diamond-like carbon. The coating can be used to have thrombosis resistance, anti-enveloping resistance or to enhance intracellular growth. In addition, the coating may be used to release locally acting medicaments and may be multilayer.

The inverted portion of the branch tube 14 may be disposed by attaching the short handle, tab or strip to the distal end of the side branch that can be engaged by a trap, tweezers or similar engagement means.

Claims (12)

In a tubular graft / stent having a tubular sheath 10 having a branch tube 14, the branch tube 14 is reversed to be received in the sheath upon insertion surgery in a human or animal body, and the branch thereafter. A tubular graft / stent system, characterized in that it is flexible enough to be relocated. 2. The tubular sheath 10 according to claim 1, wherein the tubular sheath 10 has a plurality of ring-shaped rigid members 11 along its length, wherein the rigid member is made of a shape memory material and the shape of the rigid member 11 changes. , Sheath (10) is a tubular graft / stent system, characterized in that it takes a new cross-section corresponding to the rigid member along the entire length. 3. A tubular graft / stent system according to claim 2, wherein the rigid member (11) is attached to the sheath around each circumference. 4. The tubular graft / stent system according to claim 2 or 3, wherein the rigid member (11) is discontinuous so as to take a compressed shape on martensite and a large circumferential enlarged shape on austenite. 4. A tubular graft / stent system according to claim 2 or 3, characterized in that the rigid member (11) takes a spiral shape as a compression shape and a generally circular shape as an enlarged shape. 4. A tubular graft / stent system according to claim 2 or 3, wherein the rigid member is fitted with a flexible material forming a sheath cast around it. 4. A tubular graft / stent system according to claim 2 or 3, wherein the rigid member (11) fits in a pocket formed in the sheath material. 4. The tubular graft / stent system according to claim 2 or 3, wherein the rigid member (11) is sandwiched between two layers of material forming the sheath together. 4. The rigid member (11) according to claim 2 or 3, wherein the rigid member (11) comprises a portion projecting from the outer surface of the graft in a new cross section, the projection forming an anchor for placing the graft in place in the body. Tubular graft / stent system. The tubular graft / stent system according to claim 1, wherein the branch tube (14) has an additional graft / stent. 11. The tubular graft / stent system of claim 10, wherein the rigid member of the additional graft / stent is sized progressively smaller in a direction progressively away from the tubular sheath (10). 12. The cord of claim 11, wherein the additional graft / stent has a cord 15 attached to its free end to pull the additional graft / stent out of the sheath with the cord 15 when reversed into the sheath 10. A tubular graft / stent system, which can be pulled.