Medical implants with limited resistance to migration

• US 8,292,946 B2
• Filed: 10/25/2005
• Issued: 10/23/2012
• Est. Priority Date: 10/25/2005
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: Thistle, Robert, Wolfson, Mark
• Primary Examiner(s): Jackson, Gary
• Assistant Examiner(s): Schubert, Christopher
• Application Number:
  US11/258,278
• Publication Number:
  US 20070093888A1
• Time in Patent Office: 2,555 Days
• Field of Search: 623/1.13, 623/1.14, 623/1.16, 623/1.18, 623/1.36, 623/1.49, 623/1.51, 623/1.53, 623/1.54
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2002/825 having longitudinal struts
• CPC Class Codes: A61F 2002/8486 provided on at least one of the ends
• CPC Class Codes: A61F 2220/0016 with sharp anchoring protrusions, e.g. barbs, pins, spikes
• CPC Class Codes: A61F 2230/0017 Angular shapes

Abstract

An implant adapted to be retained in a body lumen includes a barb for engaging the lumen wall. The barb includes a yieldable element adapted to yield in response to a force, above a predetermined limit, tending to cause migration of the implant. The barb may comprise a shape memory material adapted to change shape when the material undergoes a stress induced phase change and thereby to disengage from the lumen wall.

Claims

1. A barb-implant combination for retaining an implant in a body lumen, the barb-implant combination comprising at least a first barb element constructed from a first material and adapted to be attached to or comprise a part of the implant and a second barb element adapted to engage a lumen in which the implant is adapted to be deployed, said second barb element comprising a second material different from the first material, wherein the second material is a shape memory material which yields by undergoing a stress induced phase change, said second barb element being adapted to resist any force tending to displace the implant to which the first barb element is attached when that force is below a pre-determined force limit and also being adapted to yield to any force tending to displace the implant when that force exceeds the pre-determined force limit, wherein the first barb element is secured to the implant by a crimp tube in which a plurality of implant elements are also secured, said plurality of implant elements comprising a first wire having a first wire end extending into and terminating in a first end of the crimp tube and a second wire having a second wire end extending into and terminating in a second end of the crimp tube, wherein the first wire end and the second wire end are secured within the crimp tube such that the crimp tube wraps around the first wire end and the second wire end.

2. The barb-implant combination as recited in claim 1, wherein at least one part of the barb is comprised of Nitinol.

3. The barb-implant combination as recited in claim 1 wherein the first barb element is an integral part of the implant.

4. The barb-implant combination as recited in claim 1 wherein the first barb element is secured to the implant.

5. The barb-implant combination as recited in claim 1 wherein the first and second implant elements secured in said crimp tube are adjacent ends of the first implant segment and the second implant element which includes an open cell structure adapted to be deployed in an aorta adjacent a juncture with renal arteries.

6. A method of affixing an implant in a body lumen such that axial force on the implant is resisted below a pre-determined force limit and not resisted above that limit, the method comprising:

(a) providing the implant with at least a first barb element constructed from a first material and adapted to be attached to or comprise a part of the implant and a second barb element adapted to engage a lumen in which the implant is adapted to be deployed, said second barb element comprising a second material different from the first material, wherein the second material is a shape memory material which yields by undergoing a stress induced phase change, said second barb element being adapted to resist any force tending to displace the implant to which the first barb element is attached when that force is below the pre-determined force limit and also being adapted to yield to any force tending to displace the implant when that force exceeds the pre-determined force limit, wherein the first barb element is secured to the implant by a crimp tube in which a plurality of implant elements are also secured, said plurality of implant elements comprising a first wire having a first wire end extending into and terminating in a first end of the crimp tube and a second wire having a second wire end extending into and terminating in a second end of the crimp tube, wherein the first wire end and the second wire end are secured within the crimp tube such that the crimp tube wraps around the first wire end and the second wire end;

(b) locating said implant in the body lumen; and

(c) affixing said implant to the body lumen thereto by engagement of the second barb element such that when the implant is translated in a direction toward the second barb element, the second barb element bends toward the first barb element when the implant experiences a force exceeding the predetermined limit.

7. An implant adapted to be affixed to a body lumen such that an axial force on the implant is resisted below a pre-selected implant force limit and not resisted above that force limit, the implant comprising:

a first wire having a first wire end;

a second wire having a second wire end;

a barb element having a first barb segment and a second barb segment, the first barb segment element constructed from a first material, the second barb segment comprising a second material different from the first material, the second material being adapted to resist any force is tending to displace the implant to which the barb element is attached when that force is below a pre-determined force limit and also being adapted to yield to any force tending to displace the implant when that force exceeds the pre-determined force limit, wherein the second material is shape memory material which yields by undergoing a stress induced phase change; and

a crimp tube having a first crimp tube end into which the first wire end and the first barb segment are inserted and a second crimp tube end into which the second wire end is inserted, such that the first wire end, the first barb segment, and the second wire end are secure within the crimp tube such that the crimp tube wraps around the first wire end, the first barb segment, and the second wire end.

8. A barb-implant combination for retaining an implant in a body lumen, the barb-implant combination comprising a barb element having at least a first barb segment extending in a first direction and adapted to be attached to or comprise a part of the implant and to not engage the body lumen and a second barb segment extending in a second direction generally opposite the first direction and adapted to engage a lumen in which the implant is adapted to be deployed, said first barb segment constructed from a first material and said second barb segment comprising a second material different from the first material, wherein the second material is a shape memory material, the second barb segment being adapted to resist any force tending to displace the implant to which the first barb segment is attached when that force is below a pre-determined force limit and the second barb segment also being adapted to yield to any force tending to displace the implant when that force exceeds the pre-determined force limit by flipping back toward the first barb segment such that the second barb segment extends generally toward the first direction.

9. The barb-implant combination according to claim 8, further comprising a crimp tube coupled to the first barb segment and to the implant, the crimp tube retaining the barb to the implant.