A rotating, locking, spring-loaded disk implant for stabilizing adjacent vertebrae. The implant is substantially rectangular in cross-sectional shape with minimal height and maximal width. The implant is inserted into the space between two adjacent vertebrae from which a portion of the intervertebral disk has been removed and, when positioned in the disk space, rotated to bring the sides of the rectangularly-shaped implant defining the width of the implant, with its larger dimension, into engagement with the bodies of the adjacent vertebrae. A portion of the implant is biased away from the implant and into contact with the adjacent vertebrae to provide a cushioning effect between the implant and the vertebra. A lock is then secured to the implant to resist further rotation of the implant in the disk space.
