Expandable corpectomy spinal fusion cage
An intervertebral expandable spacer having a pair of co-axial annuluses locked together by an engagement member having i) a set screw and ii) a pressure plate having an outer face contacting the set screw and an inner face having teeth adapted to mate with the ratchet notches of the second member.
1. A spacer for insertion between two vertebrae, said spacer having a variable axial height and comprising a first member and a second member guided within the first member to be slidable relative thereto in an axial direction thereof for adjusting an overall height,
wherein the second member comprises an outer wall and ratchet notches provided at its outer wall facing the first member and extending in the axial direction,
wherein the first member comprises a wall having an engagement member, which cooperates with the ratchet notches for adjusting the overall height of the spacer, and
wherein the engagement member comprises i) a set screw and ii) a pressure plate having an outer face contacting the set screw and an inner face having teeth adapted to mate with the ratchet notches of the second member,
wherein the first member comprises a distal portion having an assembly pin, and the second member comprises a distal portion having a corresponding assembly groove, and the assembly groove mates with the assembly pin in order to maintain the second member in a slidable orientation within the first member.
2. The spacer of claim 1 wherein the set screw is a sole screw of the engagement member.
3. The spacer of claim 1 wherein the set screw has a cylindrical outer surface that is threaded.
4. The spacer of claim 1 wherein the set screw is tubular defining an axis with a plurality of internal axial recesses extending along the axis.
5. The spacer of claim 1 wherein the set screw comprises a distal end and a neck and head extension extending from the distal end so as to provide engagement with a corresponding neck and head recess of the pressure plate.
6. The spacer of claim 1 wherein the inner face of the pressure plate has at least two elongated teeth thereon forming at least one notch therebetween.
7. The spacer of claim 1 wherein the first member has a graft window therein for inserting graft material therethrough.
8. The spacer of claim 1 wherein the second member has a graft window therein for inserting graft material therethrough.
9. The spacer of claim 1 wherein the first and second members each have a graft window therein for inserting graft material therethrough.
10. The spacer of claim 9 wherein an anterior portion of the member annulus has a cutout upon its inner end that forms the second graft window.
11. The spacer of claim 1 wherein the teeth of the pressure plate extend perpendicular to the axial direction of the spacer.