Direct current stimulation of spinal interbody fixation device

• US 6,292,699 B1
• Filed: 01/29/1999
• Issued: 09/18/2001
• Est. Priority Date: 01/29/1999
• Status: Expired due to Term

• Current Assignee: EBI LLC (Zimvie Incorporated)
• Original Assignee: Electro-Biology Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Simon, Bruce J., Schwardt, Jeffrey D.
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US09/240,111
• Time in Patent Office: 963 Days
• Field of Search: 607/51, 607/75, 607/2, 607/52, 607/50, 623/17, 623/16, 623/17.11, 623/16.11
• US Class Current: 607/51
• CPC Class Codes: A61N 1/205 for promoting a biological process

Abstract

A spinal fusion stimulator comprising an interbody fusion cage or other interbody fixation device adapted to be implanted in the intervertebral disc space of a patient'"'"'s spine, the interbody fusion cage in the preferred embodiment having a hollow body with internal and external conductive surfaces. The stimulator includes a constant current generator connected to the interbody fusion cage and set to provide a DC current effective to produce a surface current density of at least 1 μA/cm² in the interbody fusion cage when implanted.

Claims

1. A method of stimulating spinal fusion, comprising:

implanting an interbody fixation device in the intervertebral disc space of a patient'"'"'s spine; and

supplying a constant DC current to said interbody fixation device at a level based on the exposed electrically conductive surface area of said interbody fixation device and a predetermined desired surface current density.

2. The method of claim 1, wherein said constant DC current is supplied at a current level effective to produce a surface current density in the range of approximately 1-150 μ

A/cm².

3. The method of claim 2, wherein said interbody fixation device has a total exposed conductive surface area of at least 20 cm².

4. The method of claim 3, wherein said constant DC current is supplied at a current level effective to produce a surface current density in the range of approximately 1-40 μ

A/cm².

5. The method of claim 4, wherein said constant DC current is supplied for a treatment period in the range of 1-12 months.

6. The method of claim 1, wherein said constant DC current is greater than 20 μ

A.

7. The method of claim 6, wherein said constant DC current is approximately 100 μ

A and wherein said surface current density is approximately 5 μ

A/cm².

8. The method of claim 1, wherein said surface current density is approximately 5 μ

A/cm².

9. The method of claim 1, wherein said constant DC current is supplied at a current level effective to produce a surface current density in the range of approximately 1-40 μ

A/cm².

10. The method of claim 9, wherein said constant DC current is supplied for a treatment period in the range of 1-12 months.

11. A method of stimulating spinal fusion, comprising:

implanting an interbody fixation device in the intervertebral disc space of a patient'"'"'s spine; and

supplying a constant DC current to said interbody fixation device at a level set for a predetermined range of sizes of said interbody fixation device to produce a surface current density in a range between 1 and 40 μ

A/cm².

12. The method of claim 11, wherein said range is approximately 2-20 μ

A/cm².

13. The method of claim 12, wherein said range is approximately 2-5 μ

A/cm².