A flexible expandable stent

The invention relates to medicine. It describes a flexible tubular extender implantable into a living organism.

Various extenders are known. An expander is a device made of a compatible tissue with living tissue that is used to expand blood vessels or other body openings and to maintain the size of the resulting opening. In most cases, the expander with the inflatable balloon in it is inserted into the desired position in the body, then the balloon is inflated, the expander expands and thus expands the opening. Other mechanical devices extending the extender are also used.

Wire extenders are described in U.S. Pat. No. 5,019,090, no. 5,161,547, no. No. 4,950,227, no. No. 5,314,472, no. No. 4,886,062, no. No. 4,969,458; 4,856,516 patents. Expanders made of metal are described in U.S. Pat. No. 733,665, no. No. 4,762,128, no. No. 5,102,417, no. No. 5,195,984 and International Application Ser. WO 91 FR 013820.

The expanders described in U.S. Patent No. 5,102,417 have expandable tubular members interconnected by flexible couplings. Many longitudinal cutouts are made in the tubular elements. Flexible couplings are screw couplers. Because the tubular members are rigid, flexible connectors are needed to allow the expander to be bent by pushing it through a curved blood vessel. When the extenders described in U.S. Pat. 5 102 417, expandable, tubular members expand in transverse direction and shrink in longitudinal direction. At the same time, the screw couplers rotate. This rotation causes damage to blood vessels.

U.S. Pat. No. 5,195,984 discloses a similar extender having only one straight coupling between tubular members parallel to their longitudinal axis. This straight connector prevents twisting but is not rigid.

It is an object of the present invention to provide a flexible extender that minimizes longitudinal contraction during expansion.

The extender of the present invention consists of a tube having first and second pivoting elements with axes directed in two different directions. The second winding elements overlap with the first. The first and second directions can be orthogonal.

In one embodiment of the present invention, the first winding elements are porous and non-porous elements. The porous and non-porous first winding elements are rotated 180 ° relative to each other, the non-porous element being between the two porous elements. The second winding elements may also be porous and non-porous.

In addition, the second hinged elements have two loops to which the first and the same hinged first hinged elements are connected.

The second winding elements may also be porous and non-porous. In this case, the porous and unpaired first winding elements have loops, and the porous and unpaired second winding elements are connected to the porous and unpaired first winding elements so that one loop remains between each pair of the porous and unpaired second winding elements.

The first and second winding elements described in the present invention may be made of sheet metal or wire. Their surface can be coated with any compatible fabric that is live.

The invention will now be further described with reference to the drawings in which:

Fig. 1 is a view of an extender constructed and operated in accordance with a first embodiment of the present invention;

Fig. -2 shows the extender pattern;

Fig. 3 shows a folded extender;

Figure 4 shows an expanded expander;

Figures 5A and 5B show constructional changes of the expander as it expands;

Fig.6 is a schematic representation of a second extender;

Fig. 7 is a schematic view of a third extender; and

Figure 8 shows an expanded third extender.

Figures 1-4 illustrate a first embodiment of an extender constructed and operated in accordance with the principles of the present invention. Figure 1 shows an unexpanded expander, Figure 2 shows an expander pattern, Figure 3 shows a slightly bent expander, and Figure 4 shows an expanded expander.

The extender of the present invention is a tube having a wall of a plurality of two types of orthogonal pivoting elements which overlap one another. The term "bending element" means a periodically repeating element with respect to the centerline, and the term "orthogonal bending elements" denotes elements whose centerlines are stamen to one another.

In Figs. 1-4, two curved elements are denoted by 1 and 2. They are most clearly seen in Fig. 2. The winding element 1 is a vertical sinusoid having a vertical centerline 3. The winding element 1 has two loops 4 and 5 repeated periodically, loops 4 opening to the right and loops 5 opening to the left. The loops 4 and 5 have common elements 6 and 7, the element 6 connects the loop 4 to the next loop 5, and the element 7 connects the loop 5 to the next loop 4.

The pivoting element 2 is a horizontal element having a horizontal center line 8. The periodically repeating pivoting element 2 also has loops 9 and 10 between which is a straight portion 11. The loops 9 open downward and the loops 10 open upwards. The vertical pivoting elements 1 are arranged in pairs and unpaired, i.e., they are rotated 180 ° relative to each other. Thus, each loop 5 of the hinged element 1 opening to the left is directed to the loop 4 of the other hinged element 1 opening to the right, and the loop 4 of the hinging element 1 opening to the right is directed to the loop of the hinging element 1. 5, opening to the left.

The horizontal wavy elements 2 are also arranged in an even or even order. The straight elements 11 of the horizontal pivoting element 2a intersect with every third common element 7 of the vertical pivoting element la, and the straight elements 11 of the element 2b intersect with every third common element 6. This results in a complete loop 4 between the pivoting elements 2a and 2b between elements 2b and 2a.

The pattern of the expander is shown in Fig. 2. The expander is made of a easily deformable material such as metal. By twisting it, the tubular extender 12 shown in FIG. It consists of two winding elements and has a catheter balloon expander that is flexible and can move easily through curved blood vessels.

Figure 3 shows a curved extender. It begins to tend to the point A in the direction of arrow 13. When the extender is curved, part I is inside the curve and part II is outside. The inner part I of the curve shortens with respect to the outer part II of the curve. As the extender is flexed, the loops 4-10 to the right of point A change shape, compensating for the difference in length between the inner and outer curves. For example, loops 9a and 10a on the inner side I of the curve are compressed, and loops 9b and 10b on the outer side II of the curve are stretched. Similarly, loops 4a and 5a on the inner side of the curve I are compressed and loops 4b and 5b on the outer side of the curve II are stretched.

As can be seen, both curved elements 1 and 2 are deformed by bending the extender. The expander shown in Figs. 1-4 can be bent at several places in any direction.

Figure 4 shows an expanded expander. Both curved elements 1 and 2 are expanded simultaneously (ie all loops 4-10 open). As can be seen in Fig. 4, the expanded expander has two enclosed spaces: a large space 14 between the curved elements 2b and 2a and a small space 15 between the elements 2a and 2b. Each large space 14 has two loops 4 on the left side and two loops 5 on the right. The large spaces 14a between the vertical winding elements la and lb have loops 9 at the top and the bottom and the large spaces 14b between the vertical winding elements lb and la have loops at the top and bottom 10. Similarly, the small spaces 15a and 15b are constructed.

It should be emphasized that the orthogonal curved elements 1 and 2 have very slight shrinkage during expansion. This is illustrated in Figures 5A and 5B. Fig. 5A shows the change in movement of one vertical curved member 1 during expansion of the extender, and Fig. 5B shows an analogous change in the motion of the horizontal curved member 2. The starting position of the elements is represented by a solid line and the expanded elements are represented by a dashed line.

The vertical pivoting element 1 shown in Fig. 5A expands as the loops 4 and 5 expand, and then the vertical pivoting element 1 shifts in the vertical direction by size 2hi and shrinks in the horizontal direction by size 2di. Similarly, the horizontal hinging elements 2 shown in FIG. 5B expand as the loops 9 and 10 expand, and then the horizontal hinging elements 2 move horizontally by size 2d.₂ and shrinks in the vertical direction by size h₂. Thus, the vertical displacement of the vertical pivot element 1 compensates for the vertical contraction of the horizontal pivot element 2, and vice versa. It should be noted that the displacement of the ends of any extender is only partially compensated and therefore slightly shrinks.

Obviously, the two orthogonal pivoting elements 1 and 2 and their mutual offset displacement provide flexibility for the unexpanded expander shown in FIG. However, as the dilator expands, the loops 4 and 5, due to changes, become rigid and retain the resulting internal diameter of the dilated vessel.

The extender of the invention may be made of a flat material having the configuration shown in FIG. The resulting template is then twisted to form a tube 12. A similar template can also be made of wire by welding or twisting.

It will be appreciated that the extender described herein may be made of metal and / or wire and may further be coated with a protective, medically acceptable, material and / or coated with a material that can fill between 42 and 44.

Obviously, the present invention combines all extensions of two orthogonal or otherwise curved elements. Fig. 6 schematically illustrates an alternative configuration of an extender comprising orthogonal curved elements, and Fig. 7 shows a similar extender with rounded corners of the curved elements. An enlarged view of the extended extender pattern is shown in Fig. 8. The pattern of the expander shown in Figs. 6 and 7 is similar to the pattern in Fig. 2, except that it has more horizontal curved elements 2 and is homogeneous rather than porous and non-porous as shown in Fig. 2.

Figs. 6 and 7 show two types of vertical pivoting elements la and lb rotated 180 degrees relative to each other. The horizontal curved members 2 are connected to each line of the vertical curved member la.

Figure 8 shows an expanded expander. Since it does not have porous and unpaired horizontal curved elements, it has no large or small spaces. They are all the same.

It will be clear to those skilled in the art that the present invention is not limited to what has been described and described, unless it is within the scope of its claims.

DEFINITION OF INVENTION