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.
