Medical devices incorporating sim alloy elements

• US 4,665,906 A
• Filed: 05/21/1986
• Issued: 05/19/1987
• Est. Priority Date: 10/14/1983
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Raychem Limited (TE Connectivity Limited)
• Inventors: Jervis, James E.
• Primary Examiner(s): Rosenbaum, C. Fred
• Assistant Examiner(s): Shedd, C. W.
• Application Number:
  US06/865,703
• Time in Patent Office: 363 Days
• Field of Search: 128/92 R, 128/92 YN, 128/92 YF, 128/92 YZ, 128/92 YP, 128/92 YG
• US Class Current: 606/78
• CPC Class Codes: A61B 17/0642 for bones, e.g. for osteosynthesis or connecting tendon to bone
• CPC Class Codes: A61B 17/08 Wound clamps or clips, i.e. not or only partly penetrating the tissue suture bridges A61B17/0466; Devices for bringing together the edges of a wound
• CPC Class Codes: A61B 17/72 Intramedullary pins, nails or other devices A61B17/744 takes precedence
• CPC Class Codes: A61C 2201/007 using shape memory effect
• CPC Class Codes: A61C 7/12 Brackets; Arch wires; Combinations thereof; Accessories therefor
• CPC Class Codes: A61F 2/0004 Closure means for urethra or rectum, i.e. anti-incontinence devices or support slings against pelvic prolapse
• CPC Class Codes: A61F 2/01 Filters implantable into blood vessels
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/2409 Support rings therefor, e.g. for connecting valves to tissue annuloplasty rings A61F2/2442
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• 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 6/14 intra-uterine type
• CPC Class Codes: A61L 2400/16 Materials with shape-memory or superelastic properties
• CPC Class Codes: A61L 27/04 Metals or alloys
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials

Abstract

Medical devices which are currently proposed to use elements made from shape memory alloys may be improved by the use of stress-induced martensite alloy elments instead. The use of stress-induced martensite decreases the temperature sensitivity of the devices, thereby making them easier to install and/or remove.

Claims

1. A method of installing a pseudoelastic shape-memory alloy medical device within a mammalian body, or in such proximity to a mammalian body that the device is substantially at body temperature wherein the pseudoelastic shape-memory alloy medical device displays reversible stress-induced martensite at body temperature, the method comprising:

deforming the medical device into a deformed shape different from a final shape, said deforming occurring by the formation of stress-induced martensite;

restraining the deformed shape of the medical device by the application of a restraining means;

positioning the medical device and restraining means within, or in proximity to, the body;

removing the restraining means;

isothermally transforming the device from the deformed shape into the final shape.

2. A method of installing a medical device within a mammalian body, or in such proximity to a mammalian body that the device is substantially at body temperature, the method comprising:

manufacturing the medical device at least partly from a pseudoelastic shape-memory alloy wherein the pseudoelastic shape-memory alloy medical device displays reversible stress-induced martensite at body temperature;

deforming the medical device into a deformed shape different from a final shape, said deforming occurring by the formation of stress-induced martensite;

restraining the deformed shape of the medical device by the application of a restraining means;

positioning the medical device and restraining means within, or in proximity to the body;

removing the restraining means;

isothermally transforming the device from the deformed shape into the final shape.

3. A medical device assembly for use within a mammalian body or in such proximity to a mammalian body that the medical device is substantially at body temperature, comprising:

a medical device and a restraining means;

said medical device at least partly being made of a pseudoelastic shape-memory alloy displaying reversible, stress-induced martensite at body temperature;

said medical device being deformed by the formation of stress-induced martensite into a shape different from a final shape and then restrained in the deformed shape by said restraining means;

said medical device and said restraining means being positioned in the body whereupon the restraining means is removed and the medical device isothermally transforms from the deformed shape into the final shape.

4. The medical device assembly of claim 3 wherein said medical device comprises a heart valve having a valve body, a sewing cuff and a pseudoelastic shape-memory alloy ring employed to hold the sewing cuff onto the valve body.

5. The medical device assembly of claim 3 wherein said medical device comprises a catheter.

6. The medical device assembly of claim 5 wherein said catheter is a tracheal catheter.

7. The medical device assembly of claim 3 wherein said medical device comprises an intrauterine contraceptive device.

8. The medical device assembly of claim 3 wherein said medical device is a bone plate.

9. The medical device assembly of claim 3 wherein said medical device is a marrow nail.

10. The medical device assembly of claim 3 wherein said medical device is a dental arch wire.

11. The medical device assembly of claim 3 wherein said medical device is a bone staple.

12. The medical device assembly of claim 3 wherein said medical device is a clip.