Methods and apparatus for treating disc herniation and preventing the extrusion of interbody bone graft
Methods for treating an annulus fibrosis having a defect include inserting a flexible device into the defect. The flexible device is advanced distally beyond an outer layer of the annulus fibrosus. The flexible device is then expanded such that a width of the flexible device is larger than the defect, where the flexible device prevents escape of nucleus pulposus through the defect. The flexible device may have at least two appendages made from a shape-memory metal. Alternatively, the flexible device may have a U-shaped structure that includes a central portion and two legs. The flexible device may also be anchored to the annulus fibrosis and/or the vertebrae.
1. A method for treating a defect in an annulus fibrosis of an intervertebral disc, the intervertebral disc being located intermediate an upper vertebra and a lower vertebra, the method comprising the steps of:
providing a flexible device having a distal end, a proximal end, and a midsection extending between the distal end and the proximal end, the midsection having a first surface and a second surface;
inserting the flexible device into the defect in the annulus fibrosis so that the distal end is positioned within an intradiscal space, the midsection extends across and beyond the periphery of the area defining the defect in the annulus fibrosis and the first surface of the midsection faces the nucleus; and
attaching the proximal end of the flexible device to one of the upper vertebra or lower vertebra;
wherein the distal end of the flexible device resiliently engages and rests against an endplate of the other of the upper vertebra or lower vertebra,
wherein said flexible device prevents escape of nucleus pulposus through the defect in the annulus fibrosis; and
wherein the distal end of said flexible device maintains contact with the vertebral endplate of the other of the upper vertebra or lower vertebra under distraction of the intervertebral disc.
2. The method of claim 1 , wherein the flexible device is made from a shape memory material.
3. The method of claim 1 , wherein the proximal end of said flexible device is attached to the upper vertebra.
4. The method of claim 3 , wherein the distal end of said flexible device engages and rests against the endplate of the lower vertebra.
5. The method of claim 4 , wherein the distal end of said flexible device slidingly engages the endplate of the lower vertebra.
6. The method of claim 3 , wherein the proximal end of said flexible device is attached to the endplate of the upper vertebra.
7. The method of claim 6 , wherein the proximal end of said flexible device is attached to the endplate of the upper vertebra by at least one fastener which extends transverse to the endplate of the upper vertebra.
8. The method of claim 1 , wherein said proximal end of said flexible device is attached to the lower vertebra.
9. The method of claim 8 , wherein the proximal end of said flexible device is attached to the endplate of the lower vertebra.
10. The method of claim 9 , wherein the proximal end of said flexible device is attached to the endplate of the lower vertebra by at least one fastener which extends transverse to the endplate of the lower vertebra.
11. The method of claim 8 , wherein the distal end of said flexible device engages the endplate of the upper vertebra.
12. The method of claim 11 , wherein the distal end of said flexible device slidingly engages the endplate of the upper vertebra.
13. The method of claim 1 , wherein said flexible device allows movement between the upper vertebra and lower vertebra.
14. The method of claim 1 , wherein said flexible device flexes under compression of the intervertebral disc.
15. The method of claim 1 , wherein said flexible device returns to an elongated shape under distraction of the intervertebral disc.
16. The method of claim 1 , wherein the distal end of said flexible device maintains contact with the vertebral endplate of the other of the upper vertebra or lower vertebra under compression of the intervertebral disc.
17. The method of claim 1 , wherein the distal end of said flexible device moves relative to a vertebral endplate of the other of the upper vertebra or lower vertebra under compression of the intervertebral disc.
18. The method of claim 1 , wherein the distal end of said flexible device moves relative to a vertebral endplate of the other of the upper vertebra or lower vertebra under distraction of the intervertebral disc.