Orthopedic implants, methods of use and methods of fabrication

• US 20040220672A1
• Filed: 05/03/2004
• Published: 11/04/2004
• Est. Priority Date: 05/03/2003
• Status: Abandoned Application

• Current Assignee: Dfine Incorporated (Merit Medical Systems, Inc.)
• Original Assignee: Dfine Incorporated (Merit Medical Systems, Inc.)
• Inventors: Shadduck, John H.
• Application Number:
  US10/837,858
• Publication Number:
  US 20040220672A1
• Time in Patent Office: Days
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/00234 for minimally invasive surgery A61B17/0218, A61B17/0469, A61B17/12013, A61B17/1285, A61B17/29, A61B17/320016 take precedence
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/2825 Femur
• CPC Class Codes: A61F 2002/2892 Tibia
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30069 elastomeric
• CPC Class Codes: A61F 2002/30075 swellable, e.g. when wetted
• CPC Class Codes: A61F 2002/3008 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30583 filled with hardenable fluid, e.g. curable in-situ
• CPC Class Codes: A61F 2002/30586 : having two or more inflatable pockets or chambers
• CPC Class Codes: A61F 2002/30604 : modular
• CPC Class Codes: A61F 2002/30677 : Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/3092 : having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30962 : using stereolithography
• CPC Class Codes: A61F 2002/30975 : made of two halves
• CPC Class Codes: A61F 2002/443 : having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2002/444 : for replacing the nucleus pulposus
• CPC Class Codes: A61F 2002/4627 : with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2002/4631 : the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2002/4635 : using minimally invasive surgery
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2210/0014 : 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 2210/0033 : electrically, e.g. heated by resistor
• CPC Class Codes: A61F 2210/0038 : electromagnetically
• CPC Class Codes: A61F 2210/0047 : heated by light
• CPC Class Codes: A61F 2210/0061 : swellable
• CPC Class Codes: A61F 2210/0085 : hardenable in situ, e.g. epoxy resins
• CPC Class Codes: A61F 2220/005 : using adhesives
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0018 : differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0023 : differing in porosity
• CPC Class Codes: A61F 2250/0098 : radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2310/00353 : Bone cement, e.g. polymethylmethacrylate or PMMA
• CPC Class Codes: A61L 2400/16 : Materials with shape-memory or superelastic properties
• CPC Class Codes: A61L 2430/38 : for reconstruction of the spine, vertebrae or intervertebral discs
• CPC Class Codes: A61L 27/48 : with macromolecular fillers
• CPC Class Codes: A61L 27/56 : Porous materials, e.g. foams or sponges

Abstract

An orthopedic implant device that is adapted for providing a support structure in spine treatments and other bone treatments. In several embodiments, an exemplary implant body is capable of a first compacted shape and a second expanded shape. The implant is microfabricated of an open cell elastomeric shape memory polymer (SMP) composition. The implant has a first shape for deployment with the SMP in its temporary compacted shape. When deployed in an orthopedic space, the polymer monolith transforms to its memory shape to occupy the space. In several embodiments, the open cell implant body is then infused with an in-situ polymerizable composition to create a composite resilient, fiber-reinforced implant. In another embodiment, the implant body is in-filled with a bone-cement such as PMMA to fill a cavity in a bone, wherein the elastomeric open cell monolith deforms to provide a substantially fluid-impermeable surface around the bone cement.

Claims

1. A spine implant comprising a body for dimensioned for engaging spine structure including an open cell shape memory polymer.

2. A spine implant as in claim 1 wherein the open cell shape memory polymer has a gradient in open cell volume.

3. A spine implant as in claim 1 wherein the open cell shape memory polymer is a soft lithography microfabricated structure.

4. A spine implant as in claim 1 wherein the open cell shape memory polymer is a foam.

5. A spine implant as in claim 1 wherein the body has a first unstressed state and is releasably maintainable in a second stressed state having a compacted shape.

6. A spine implant as in claim 5 wherein the body is transformable to the first unstressed state from the second stressed state in response to a controllable stimulus.

7. A spine implant as in claim 6 wherein the stimulus is temperature.

8. A spine implant as in claim 7 wherein the stimulus is temperature between about 35°

C. and 120°

C.

9. A spine implant as in claim 5 wherein the shape memory polymer is the first unstressed state has a modulus of ranging between 10 KPa and 5 MPa.

10. A spine implant as in claim 1 wherein the body further includes reinforcing fibers.

11. A spine implant as in claim 5 wherein the body is dimensioned in its unstressed state for occupying a space selected from the class consisting of a disc nucleus space, a space about the interior of a disc annulus, and a space in a bone.

12. A spine implant as in claim 1 further comprising an in-situ polymerizable composition for introducing into an interior of the body for creating a composite implant.

13. A spine implant as in claim 1 further comprising a radiovisible element within the body.

14. A method of treating an orthopedic abnormality comprising:

(a) providing an implant body of an open cell shape memory polymer that is releasably maintained in a compacted, stressed state;

(b) introducing the implant body into a space within orthopedic structure; and

(c) causing the implant body to transform in shape to an expanded, unstressed state.

15. A method of treating an orthopedic abnormality as in claim 14 wherein the implant body expands to position reinforcing fibers about the interior of a disc annulus.

16. A method of treating an orthopedic abnormality as in claim 14 wherein the implant body expands to occupy a disc nucleus space, and further comprises the step of infilling open cell body with an in-situ polymerizable composition.

17. A method of treating an orthopedic abnormality as in claim 14 wherein the implant body expands to occupy a space in a bone, and further comprises the step of introducing a bone cement into an interior of the implant body.

18. A method of treating an orthopedic abnormality as in claim 17 wherein the implant body forms a substantially fluid impermeable layer around the bone cement.

19. A method of making an orthopedic implant device comprising microfabricating a polymeric body having a substantially open interior volume by microfabrication means selected from the class consisting of soft lithography means, electrospinning means and foaming means.

20. A method of making an orthopedic implant device as in claim 19 wherein the body includes a shape memory polymer.