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 surrounding nucleus pulposus of an intervertebral disc, the intervertebral disc located between an upper and a lower vertebra, the method comprising the steps of:
advancing a flexible device into the space between the upper vertebra and the lower vertebra so as to close off the defect in the annulus fibrosis, the flexible device having a first portion, a second portion and a middle portion connecting the first portion to the second portion, wherein the flexible device is advanced so that the first portion is disposed distally of the middle portion and the second portion, with the first portion contacting one of the upper vertebra and the lower vertebra, the middle portion extending from the first portion proximally through the space between the upper vertebra and the lower vertebra to the second portion, and the second portion contacting the other of the upper vertebra and the lower vertebra; and
attaching the second portion to the one of the upper vertebra and the lower vertebra contacted by the second portion,
wherein the flexible device blocks extrusion of nucleus pulposus through the defect in the annulus fibrosis.
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 second portion is attached to the upper vertebra.
4. The method of claim 3 , wherein the first portion contacts the vertebral endplate of the lower vertebra.
5. The method of claim 4 , wherein said first portion of said flexible device slidingly engages the endplate of the lower vertebra.
6. The method of claim 3 , wherein said second portion of said flexible device is attached to the endplate of the upper vertebra.
7. The method of claim 6 , wherein said second portion 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 the second portion is attached to the lower vertebra.
9. The method of claim 8 , wherein said second portion of said flexible device is attached to the endplate of the lower vertebra.
10. The method of claim 9 , wherein said second portion 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 said first portion of said flexible device engages the endplate of the upper vertebra.
12. The method of claim 11 , wherein said first portion of said flexible device slidingly engages the endplate of the upper vertebra.
13. The method of claim 1 , wherein the flexible device allows movement between the upper and lower vertebrae.
14. The method of claim 1 , wherein the flexible device flexes under compression of the disc.
15. The method of claim 1 , wherein the flexible device returns to an elongated shape under distraction of the disc.
16. The method of claim 1 , wherein the first portion maintains contact with the vertebral endplate of the one of the upper or lower vertebra contacted by the first portion under compression of the disc.
17. The method of claim 1 , wherein the first portion maintains contact with the vertebral endplate of the one of the upper or lower vertebra contacted by the first portion under distraction of the disc.
18. The method of claim 1 , wherein said first portion of said flexible device moves relative to a vertebral endplate of the one of the upper vertebra or lower vertebra contacted by the first portion under compression of the intervertebral disc.
19. The method of claim 1 , wherein said first portion of said flexible device moves relative to a vertebral endplate of the one of the upper vertebra or lower vertebra contacted by the first portion under distraction of the intervertebral disc.