Resilient prosthesis for widening a channel, particularly a blood vessel, and method for making same

• US 5,749,919 A
• Filed: 09/07/1995
• Issued: 05/12/1998
• Est. Priority Date: 01/10/1994
• Status: Expired due to Term

• Current Assignee: Microfil Industries SA (UBS Ag)
• Original Assignee: Microfil Industries SA (UBS Ag)
• Inventors: Blanc, Louis
• Primary Examiner(s): Isabella, David
• Assistant Examiner(s): Black, John M.
• Application Number:
  US08/513,909
• Time in Patent Office: 978 Days
• Field of Search: 623/1, 623/11, 623/12, 600/36, 606/190, 606/191, 606/192, 606/193, 606/194, 606/195, 606/196, 606/197, 606/198, 606/199, 606/200, 140/92.1
• US Class Current: 623/1.22
• CPC Class Codes: A61F 2/88 the wire-like elements formed as helical or spiral coils forming a net-like or mesh-like structure A61F2/90
• CPC Class Codes: A61F 2250/0018 differing in elasticity, stiffness or compressibility

Abstract

A resilient prosthesis such as a stent for widening a channel in a living body, particularly a stenotic portion of a blood vessel, is disclosed. The prosthesis (5) consists of a number of lengths of resilient thread (1, 2, 3, 4) helically wound in the same direction, which threads are axially inserted between one another in a substantially cylindrical arrangement without intersecting one another. The threads may be separate or joined together at the ends of the prosthesis. The turns of the threads have a shorter pitch P₁ in the mid-portion (6) of the prosthesis than in the other portions thereof (7, 8), so that one separate thread cannot be "screwed" between the others. The ends (10, 11) of the threads all lie in the same plane or are axially offset. The prosthesis may be manufactured at low cost and is useful for performing angioplastic, urological or gynaecological treatments, and generally for widening or supporting any channel in the human or animal body.

Claims

1. An elastic prosthesis, having a median section bound by regions of extremity, for widening a conduit in a living being, in particular a blood vessel, said elastic prosthesis being of a substantially elongated and cylindrical shape, wherein said elastic prothesis (5, 20) comprises a plurality of elastic wire filaments (1, 2, 3, 4, 22) having a helical spiral configuration in which the helical spirals have a direction which is the same for each wire filament except in the regions of extremity of the prosthesis, the wire filaments (1, 2, 3, 4, 22) being intercalated with one another without crossing so as to form the said substantially cylindrical shape.

2. The elastic prosthesis according to claim 1, wherein the helical spiral of each wire filament has a shorter helical pitch (P₁) in the median section (6) than in the regions of extremity.

3. The elastic prosthesis according to claim 2, wherein the regions of extremity have a helical pitch (P2) which is at least 1.5 times the helical pitch (P₁) in the median section (6).

4. The elastic prosthesis according to claim 1, wherein all the wire filaments (1, 2, 3, 4, 22) are identical in size, length, shape, and helical pitch.

5. The elastic prosthesis according to claim 1, wherein the wire filaments (1, 2, 3, 4, 22) each have two free extremities (10, 11), said two free extremities are not connected to one another.

6. The elastic prosthesis according to claim 5, wherein at each extremity of the prosthesis (5), the free extremities (10, 11) of the wire filaments are substantially in a same transversal plane.

7. The elastic prosthesis according to claim 5, wherein at an extremity of the prosthesis (5), the free extremities (11) of the wire filaments are staggered axially in relation to one another.

8. The elastic prosthesis according to claim 1, wherein the elastic prosthesis comprises a number of wire filaments (1, 2, 3, 4, 22), where the number of wire filaments is between 4 and 18 inclusive.

9. The elastic prosthesis according to claim 1, wherein at the extremity of the prosthesis (20), adjacent wire filaments (22) are connected.

10. The elastic prosthesis according to claim 9, wherein at least some of the wire filaments (22) are connected by welding.

11. The elastic prosthesis according to claim 9, wherein at least some of the wire filaments (22) are formed from a single continuous wire which is folded or bent through 180°

at each extremity of the prosthesis in order to connect in each case two of the said wire filaments.

12. An elastic prosthesis, having a median section bound by regions of extremity, for widening a conduit in a living being, in particular a blood vessel, said elastic prosthesis being of a substantially elongated and cylindrical shape, wherein said elastic prosthesis (5, 20) comprises a plurality of elastic wire filaments (1, 2, 3, 4, 22) having a helical spiral configuration in which the helical spirals have a direction which is the same for each wire filament except in the regions of extremity of the prosthesis, the wire filaments (1, 2, 3, 4, 22) being intercalated with one another without crossing so as to form the said substantially cylindrical shape;

the wire filaments (1, 2, 3, 4,

     22) each having two free extremities (10,

     11), said two free extremities not being connected to one another; and

wherein

at an extremity of the elastic prosthesis (5'"'"'), the free extremities (11) of the wire filaments are staggered axially in relation to one another.

13. A method of manufacturing an elastic prosthesis from a continuous metal wire, the prosthesis (5, 20) having a median section bound by more than one region of extremity, for widening a conduit in a living being, in particular a blood vessel, said elastic prosthesis being of a substantially elongated and cylindrical shape and comprising a plurality of elastic wire filaments (1, 2, 3, 4, 22) having a helical spiral configuration in which the helical spirals have a direction which is the same for each wire filament except in the regions of extremity of the prosthesis, the wire filaments (1, 2, 3, 4, 22) being intercalated with one another without crossing so as to form the said substantially cylindrical shape;

adjacent wire filaments (22) in the regions of extremity are connected;

at least some of the wire filaments (22) are formed from a single continuous wire which is folded or bent through 180°

at each extremity of the prosthesis in order to connect in each case two of the said filaments;

comprising the following steps;

providing a means of support comprising a first and a second support (24,

     25) with a circular periphery and axially aligning one facing the other and each having a series of protruding elements (28,

     30) distributed along the periphery of the support, and a central mandrel (29) arranged axially between the two series of protruding elements;

placing the wire on the means of support in a zigzag fashion using an axial zigzag movement between the two series of protruding elements (28,

     30) in order to form an assembly of axial wire filaments (22) which are parallel and distributed around the mandrel, the wire being folded successively around at least one protruding element of the initial support and then of the second support, then around at least one other protruding element of the initial support and so on;

cutting the wire to form two adjacent extremities, said extremities being fixed one to the other;

twisting said assembly of wire filaments (22) around the mandrel (29) to confer upon each wire filament a permanent helical spiral configuration and removing said assembly which forms the prosthesis (20) from the means of support.

14. A method of manufacturing an elastic prosthesis from a continuous metal wire, the prosthesis having a median section bound by more than one region of extremity, for widening a conduit in a living being, in particular a blood vessel, said elastic prosthesis being of a substantially elongated and cylindrical shape and comprising a plurality of elastic wire filaments (1, 2, 3, 4, 22) having a helical spiral configuration in which the helical spirals have a direction which is the same for each wire filament except in the regions of extremity of the prosthesis, the wire filaments (1, 2, 3, 4, 22) being intercalated with one another without crossing so as to form the said substantially cylindrical shape;

adjacent wire filaments (22) in the regions of extremity are connected;

at least some of the wire filaments (22) are formed from a single continuous wire which is folded or bent through 180°

at each extremity of the prosthesis in order to connect in each case two of the said filaments;

comprising the following steps;

providing a supports means comprising a first and a second support (2,

     25) with a circular periphery and axially aligning one facing the other and each having a series of protruding elements (28,

     30) distributed around the periphery of the support, and a central mandrel (29) arranged axially between the two series of protruding elements;

placing the wire on the means of support in a zigzag fashion using a helical zigzag movement between the two series of protruding elements (28,

     30), or by an axial zigzag movement combined with an alternating movement of rotation of the means of support in order to form a parallel assembly of wire filaments wound round in helical spirals around the mandrel, the wire being folded successively round at least one protruding element of the initial support, then of the second support, then round at least one protruding element of the initial support and so on;

cutting the wire to form two adjacent extremities, said extremities being fixed one to the other; and

removing said assembly which forms the prosthesis (20) from the means of support.