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.

The methods disclosed herein of generating three-dimensional lattice structures and reducing stress shielding have applications including use in medical implants. One method of generating a three-dimensional lattice structure can be used to generate a structure lattice and/or a lattice scaffold to support bone or tissue growth. One method of reducing stress shielding includes generating a structural lattice to provide sole mechanical spacing across an area for desired bone or tissue growth. Some examples can use a repeating modified rhombic dodecahedron or radial dodeca-rhombus unit cell. Some methods are also capable of providing a lattice structure with anisotropic properties to better suit the lattice for its intended purpose.

An intervertebral fusion device 10 is disclosed. The intervertebral fusion device 10 comprises at least one endplate 40, 70 and a core component 20. The at least one endplate 40, 70 is configured to be received in an intervertebral space between first and second vertebrae. Each at least one endplate 40, 70 comprises first and second endplate parts which are coupled to each other to allow the first and second endplate parts to move apart to thereby increase a perimeter of the endplate. The core component 20 is configured to inter-engage with each at least one endplate 40, 70. The core component 20 is unitary. As the core component 20 is progressively brought into inter-engagement with the at least one endplate 40, 70, the core component bears against the first and second endplate parts to push the first and second endplate parts progressively apart.

In various aspects, an expandable implant for use in a surgical procedure includes a distal cage, a proximal cage mechanically connectable with the distal cage, a top expandable assembly, and a bottom expandable assembly. Each of the top and bottom expandable assemblies have a distal portion in communication with a surface of the distal cage and a proximal portion in communication with a surface of the proximal cage. The expandable implant is expandable firstly in a medial-lateral direction, secondly in a lordotic (e.g., angular) direction, and thirdly a cranial-caudal direction. Additionally, the expandable implant may be diagonally symmetrical about a longitudinal axis of the expandable implant.

In accordance with one aspect, a spinal implant for fusing vertebral bones is provided that includes a monolithic body for being inserted between bones. The body has a through opening of the body for receiving bone growth material and a wall of the body extending about the through opening. The wall includes nubs extending into the through opening that increase the surface area of the wall available for bone on-growth.