Spinal fusion device

A spinal fusion device, comprising:

• a first endplate configured for fitting within a disc space and engaging with a first vertebra, wherein said first endplate has an anterior end and a posterior end;
• and
• a second endplate configured for fitting within said disc space and engaging with a second vertebra, wherein said second endplate has an anterior end and a posterior end,
• wherein said endplates are separated by a single spacer that maintains a pre-determined distance between said endplates, said spacer comprising:
• an anterior end;
• a posterior end;
• a first lateral side;
• a second lateral side, opposite to said first lateral side;
• a first surface that engages with said first endplate;
• a second surface that is opposite to said first surface and engages with said second endplate;
• and
• a locking device that releasably engages with said first and second endplates and allows in situ disassembly of said spacer from said fusion device after implantation, wherein said locking device comprises:
• a first set of edges on said first surface of the spacer, said first set of edges engage with one or more slots on said first end plate;
• a second set of edges on said second surface of said spacer, said second set of edges engage with one or more slots on said second end plate;
• and
• one or more protrusions on said spacer that lock into one or more protrusion slots on one or both endplates, or one or more protrusions on one or both endplates that lock into one or more protrusion slots on said spacer,
• wherein each protrusion comprises (1) a sloped front wall that allows said protrusion to be pushed into a protrusion slot by advancing the spacer between the first and the second end plates and towards the posterior ends of the endplates until said protrusion is resiliently biased into said protrusion slot and (2) a sloped back wall that allows said protrusion to be pulled out from said protrusion slot by retracting the spacer towards the anterior end of the end plates.

A method for implanting the spinal fusion device in a subject, comprising:

• preparing a disc space between two adjacent vertebrae;
• inserting a pair of endplates into said disc space, wherein each endplate comprises an anterior end, a posterior end, a locking hole, and protrusions on an outer surface;
• inserting a spacer between said pair of endplates, wherein said spacer comprises an anterior end, a posterior end, a first surface that engages with said first endplate, a second surface that engages with said second endplate, a first flexible locking tab on said first surface, and a second flexible locking tab on said second surface;
• advancing said spacer between said pair of endplates towards the posterior end of said endplates until said locking tabs self-locks with corresponding locking holes on said first and second endplates by resiliently biasing into said locking holes.