Interbody cages are cylindrical or crescent-shaped, hollow, and porous metallic devices that are placed between two adjacent vertebrae in a spinal segment after removing the damaged disc. The cage may occupy the entire disc space or just the front (anterior) part of it. A spinal surgery that warrants removal of the disc, such as interbody fusion, usually uses interbody cages. The top and bottom of a spinal interbody cage are in contact with the vertebral endplates—the transition region where a vertebral body and intervertebral disc interface with each other. The cage is filled with bone graft material (harvested from the patient’s body or obtained from another source) that grows over time and fills within the interbody space, permanently fusing the two adjacent vertebrae of the treated segment.