A method for retaining an intra-discal material within an annulus fibrosis having a posterior annulus, an inside surface, and an opening is described. The opening has a lateral and a vertical dimension. A retention device that includes a shape memory alloy is inserted through the opening in the annulus fibrosis. The length dimension of the device is longer than the lateral dimension of the opening and the width dimension of the device is longer than the vertical dimension of the opening in the annulus fibrosis. The retention device is positioned against the posterior annulus to rest against annulus fibrosis tissues adjacent the opening on the inside surface of the annulus fibrosis such that both a portion of the length dimension and a portion of the width dimension rests against annulus fibrosis tissues adjacent the opening. The retention device prevents the escape of intra-discal material through the opening.
