Disc augmentation using materials that expand in situ

• US 20050222684A1
• Filed: 05/31/2005
• Published: 10/06/2005
• Est. Priority Date: 04/10/2002
• Status: Active Application

• Current Assignee: Anova Corp.
• Original Assignee: Anova Corp.
• Inventors: Ferree, Bret A.
• Application Number:
  US11/140,751
• Publication Number:
  US 20050222684A1
• Time in Patent Office: Days
• US Class Current: 623/17.160
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/444 for replacing the nucleus pulposus
• CPC Class Codes: A61F 2210/0014 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61L 2430/38 for reconstruction of the spine, vertebrae or intervertebral discs
• CPC Class Codes: A61L 27/50 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials

Abstract

A method of augmenting a nucleus pulposus within an annulus fibrosis. A material having a relatively thin, elongated first state is inserted through the annulus, after which it expands or otherwise assumes a shape that is more rounded when implanted. In the preferred embodiment, for introduction the material is relatively rigid or hard and relatively thin, resembling a needle or a nail. The size, shape, and consistency of the material allow the device to be pushed through the fibers of the annulus fibrosis, preferably without an incision, and into the nucleus pulposus and/or disc space. The resultant shape assists the nucleus pulposis in acting as a “shock absorber,” and the expansion of the material also makes extrusion unlikely. Various materials qualify for this purpose according to the invention. Materials that change shape with temperature include memory-effect alloys such as Nitinol and substances such as stearle methacrylate. Materials that change in shape in the presence of moisture include hydrogels and other substances that imbibe water. Materials that expand due to chemical reaction include various foams, and the like, some of which may be applied in two-part form.

Claims

1. A method of augmenting a nucleus pulposus (NP) within an annulus fibrosis (AF), the method comprising the steps of:

providing a material having a relatively thin, elongated first state and a second state which is more rounded when implanted in, or adjacent to, an NP; and

inserting the material through the AF in the first state without creating a hole in the AF so that it may expand into the second state once inside the disc.

2. The method of claim 1, wherein the material expands due to a change in temperature.

3. The method of claim 1, wherein the material expands through exposure to moisture.

4. The method of claim 1, wherein the material expands through exposure to one or more chemical or biological constituents.

5. The method of claim 1, wherein the material is inserted through the annulus fibrosis without an intentional incision.

6. The method of claim 1, wherein the second state is generally spherical.

7. The method of claim 1, wherein the second state is a wire ball.