Expandable intervertebral implant

An expandable intervertebral implant, the implant comprising:

• a superior plate having a proximal end, an opposing distal end, and a threaded first hole;
• an inferior plate having a proximal end, an opposing distal end, and a first bore, the inferior plate at least partially bounding an elongated channel that communicates with the first bore;
• a first lift screw comprising a gear wheel rotatably received within the first bore of the inferior plate and a threaded stem projecting from the gear wheel and being threaded into the first hole of the superior plate, the first lift screw having an interior surface that bounds a passage that passes entirely through the first lift screw so as to pass through the gear wheel and the threaded stem;
• a drive screw rotatably disposed within the channel of the inferior plate, the drive screw comprising a worm that engages with the gear wheel such that rotation of the drive screw facilitates rotation of the first lift screw which in turn facilitates movement of the superior plate relative to the inferior plate;
• the superior plate or the inferior plate having a pair of spaced apart arms disposed at the distal end thereof with a gap being formed between the spaced apart arms;
• and
• the other of the superior plate or the inferior plate having a tongue disposed at the distal end thereof, the tongue being disposed within the gap between the pair of spaced apart arms;
• and
• a guide pin outwardly projecting from the tongue and into a slot formed on one of the arms, the guide pin sliding along a length of the slot when the drive screw is rotated.

An expandable intervertebral implant, the implant comprising:

• a superior plate having a proximal end, an opposing distal end, and a threaded first hole, a pair of spaced apart arms are disposed at the distal end with a gap slot formed between the spaced apart arms, each of the spaced apart arms having a top face and an opposing bottom face with an inside face extending therebetween, a slot being recessed into the top face and intersecting with the inside face;
• an inferior plate having a proximal end, an opposing distal end, and a first bore, the inferior plate at least partially bounding an elongated channel that communicates with the first bore, the inferior plate further including a tongue disposed at the distal end and being received within the gap between the pair of spaced apart arms of the superior plate;
• a first lift screw comprising a gear wheel rotatably received within the first bore of the inferior plate and a threaded stem projecting from the gear wheel and being threaded into the first hole of the superior plate;
• a drive screw rotatably disposed within the channel of the inferior plate, the drive screw comprising a worm that engages with the gear wheel such that rotation of the drive screw facilitates rotation of the first lift screw which in turn facilitates movement of the superior plate relative to the inferior plate;
• and
• a pin passing through the tongue of the inferior plate so that opposing ends of the pin outwardly project from opposing ends of the tongue, each opposing end of the pin being received within the slot of a corresponding one of the spaced apart arms of the superior plate.