Intervertebral spacer that dynamically promotes bone growth

A method for dynamically fusing adjacent vertebral bodies in a patient's spine, the method comprising:

• implanting a spacer into an intervertebral space between adjacent vertebral bodies, wherein the spacer comprises a monolithic spacer having an anterior portion, a posterior portion, a superior surface, an inferior surface angled with respect to the superior surface to restore lordosis, an open center portion configured to receive bone graft, a first flange extending upwards from the superior surface, a second flange extending downwards from the inferior surface, and a split along the anterior portion running vertically between the first flange and the second flange and extending through the superior surface and the inferior surface;
• filling the central opening of the monolithic spacer with a bone graft material;
• and
• affixing at least one of the superior surface or the inferior surface to one of the adjacent vertebral bodies, the first flange with an anterior surface of the superior vertebral body, and the second flange with an anterior surface of the inferior vertebral body to create a dynamic connection between the adjacent vertebral bodies,
• wherein the relative vertical movement of the adjacent vertebral bodies enables a gradual transition from motion of the adjacent vertebral bodies to fusion of the adjacent vertebral bodies.