INTERVERTEBRAL DEVICES

Intervertebral fusion device comprising a superior component, an inferior component, and a core component. The superior component comprises first and second superior parts which are coupled to each other to allow the first and second superior parts to move apart to thereby increase a perimeter of the superior component top side. The inferior component comprises first and second inferior parts which are coupled to each other to allow the first and second inferior parts to move apart to thereby increase a perimeter of the inferior component bottom side. The core component is configured for insertion between the superior and inferior components whereby separation between the superior and inferior components is determined. The core component interengages with each of the superior and inferior components upon insertion. The superior and inferior components are unattached to each other before the core component is inserted between the superior and inferior components. As the core component is progressively inserted between the superior and inferior components, the core component: bears against the first and second superior parts to push the first and second superior parts progressively apart; and bears against the first and second inferior parts to push the first and second inferior parts progressively apart.