Medical stents for body lumens exhibiting peristaltic motion

• US 6,305,436 B1
• Filed: 03/01/1999
• Issued: 10/23/2001
• Est. Priority Date: 10/09/1991
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Urhoj, Susanne, Andersen, Erik, Strecker, Ernst Peter, Hess, Kathleen L.
• Primary Examiner(s): Larson, Lowell A.
• Application Number:
  US09/260,432
• Time in Patent Office: 967 Days
• Field of Search: 140/107, 140/89, 140/71.R, 140/71.C, 148/580, 148/597, 148/598, 623/1, 623/12, 723/700.6
• US Class Current: 140/107
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/04 Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts A61F2/18, A61F2/20 take precedence; devices, other than stent-grafts, providing patency to, or preventing collapsing of, tubular structures of the body other than stent-grafts, e.g. stents A61F2/82; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2/9522 Means for mounting a stent or stent-graft onto or into a placement instrument
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2002/072 Encapsulated stents, e.g. wire or whole stent embedded in lining
• CPC Class Codes: A61F 2002/075 the stent being loosely attached to the graft material, e.g. by stitching
• CPC Class Codes: A61F 2002/9511 the retaining means being filaments or wires
• CPC Class Codes: A61F 2210/0019 operated at only one temperature whilst inside or touching the human body, e.g. constrained in a non-operative shape during surgery, another temperature only occurring before the operation
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0078 hyperboloidal
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 31/005 Ingredients of undetermined constitution or reaction products thereof
• CPC Class Codes: A61L 31/04 Macromolecular materials
• CPC Class Codes: D04B 1/225 Elongated tubular articles of small diameter, e.g. coverings or reinforcements for cables or hoses
• CPC Class Codes: D04B 15/14 Needle cylinders
• CPC Class Codes: D10B 2509/06 Vascular grafts; stents

Abstract

Methods for forming, shaping and heat treating stents for reinforcement of the lumen of peristaltic organs. The stent is formed by knitting preferably a nitinol wire into a pattern of overlapping loops selected such that from a relaxed state each row of loops may shift axially relative to and independently of the rows on either side. This local lengthening and shortening accommodates peristalsis of the organ without migrating within the organ.

Claims

1. A method of manufacturing a wire medical device, the method comprising:

providing an elastic metal wire;

forming said wire so it defines, generally, a tube that has a first geometry,

said tube being formed by bending said wire in a substantially regular pattern that forms the walls of said tube over its length, and thereafter

shaping the tube to form a device having a second geometry, said second geometry differing from said first geometry and being effected by applying a mechanical deforming force to said tube in said first geometry so it conforms to said second geometry and, while maintaining said deforming force, heating and then cooling said tube such that said tube retains said second geometry when said mechanical deforming force is removed.

2. The method of claim 1 comprising:

mechanically deforming said tube by confining at least a portion of it within a cavity of a die having a smaller geometry than said tube.

3. The method of claim 1 comprising:

mechanically deforming said tube by confining only a portion of it within a cavity of a die having a smaller geometry than said tube.

4. The method of claim 1 comprising:

mechanically deforming said tube by stretching at least a portion of it over a mandrel having a larger diameter than said tube.

5. The method of claim 1 comprising:

mechanically deforming said tube by stretching only a portion of it over a mandrel having a larger diameter than said tube.

6. The method of claim 1 comprising:

mechanically deforming portions of said tube by confining said portions within the cavity of a die and mechanically deforming other portions of said tube by stretching said other portions over a mandrel.

7. The method of claim 1 comprising:

shaping said tube to form a stent having an end portion in the form of a flare of larger diameter than other portions of said stent.

8. The method of claim 1 comprising:

shaping said tube to form a stent that has an end portion in the form of a flare of enlarged diameter at each end of the stent and a reduced diameter portion therebetween.

9. The method of claim 8 comprising:

shaping by mechanically deforming each end portion of said tube by stretching each end portion over a mandrel having a larger diameter than said tube.

10. The method of claim 1 comprising:

forming a valve device by shaping said tube so it includes a portion of substantially reduced diameter, and

providing to said reduced diameter portion a wall material that is substantially impermeable to body fluid,

said valve device being capable of impeding the flow of body fluid through said reduced diameter portion until the pressure of said body fluid is sufficient to elastically widen said portion and allow flow therethrough, said portion of said device relaxing to said reduced diameter when the pressure of said bodily fluid decreases thereafter.

11. A method of manufacturing a wire medical device, the method comprising:

providing an elastic metal wire;

forming said wire so that it defines, generally, a self-expandable tube having a uniform diameter;

said self-expandable tube being formed by bending said wire in a substantially regular pattern that forms the walls of said self-expandable tube over its length, and thereafter

shaping the self-expandable tube to form a device having a non-uniform diameter by applying a first mechanical deforming force to only a portion of said self-expandable tube and, while maintaining said first mechanical deforming force, heating and then cooling said self-expandable tube such that said portion of said self-expandable tube retains its deformation when said first mechanical deforming force is removed.

12. The method of claim 11 wherein said first mechanical deforming force is applied by confining said portion of said self-expandable tube within a cavity of a die having a smaller geometry than said self-expandable tube.

13. The method of claim 11 wherein said first mechanical deforming force is applied by stretching said portion of said self-expandable tube over a mandrel having a larger diameter than said self-expandable tube.