Expandable push-in orthopedic implant

1. A push-in orthopedic implant for linear insertion at least in part between two adjacent bone masses, said implant comprising:

an upper member having an upper surface adapted for placement toward and into contact with one of the adjacent bone masses, said upper surface being non-arcuate along a substantial portion of the length of said implant, said upper surface having at least one opening adapted to communicate with one of the adjacent bone masses, said upper member having a proximal end and a distal end, and said upper member including a first track portion positioned adjacent one of said proximal and distal ends of said upper member;

a lower member having a lower surface adapted for placement toward and into contact with the other of the adjacent bone masses, said lower surface being non-arcuate along a substantial portion of the length of said implant, said lower surface having at least one opening adapted to communicate with the other of the adjacent bone masses, said openings of said upper and lower surfaces being in communication with one another and adapted for permitting for the growth of bone from adjacent bone mass to adjacent bone mass through said implant, said lower member having a proximal end and a distal end corresponding to said proximal end and said distal end of said upper member, respectively, and said lower member including a second track portion positioned adjacent one of said proximal and distal ends of said lower member, the position of said second track portion corresponding to the position of said first track portion, said upper and lower members contacting and articulating therebetween adjacent one of said proximal ends and said distal ends of said upper and lower members and allowing for expansion of the height of said implant, said upper and lower members having a first position relative to one another allowing for a collapsed implant height and a second position relative to one another allowing for an increased height, and said upper and lower members adapted to interlock with one another to stop said upper and lower members from being moved apart from one another more than a predetermined distance;

at least one blocker provided in said first and second track portions and positioned adjacent said one of said proximal and distal ends of said upper and lower members, said blocker adapted to cooperatively engage and hold at least a portion of said upper and lower members apart so as to maintain the increased height of said implant and resist the collapse of said implant to the collapsed implant height when said implant is in a final deployed position, said blocker being configured to rotate partially within said first and second track portions about an axis generally parallel to a longitudinal axis of said implant and to remain in a plane generally perpendicular to the longitudinal axis while transitioning said upper and lower members from said first position to said second position, said first and second track portions adapted to restrain movement of said blocker along the length of said implant; and

a hollow defined between said upper and lower members from adjacent said proximal end to adjacent said distal end in communication with said openings in each of said upper and lower surfaces, said hollow being adapted to receive fusion-promoting substances, and said hollow being unobstructed by said blocker.

2. The push-in implant of claim 1 , wherein said implant has a constant width in both the first position and the second position.

3. The push-in implant of claim 1 , wherein said implant has side walls and said blocker does not contact said side walls when said implant is in the final deployed position.

4. The push-in implant of claim 1 , wherein said blocker moves said upper and lower surfaces of said upper and lower members from one of a parallel orientation and an angled orientation relative to one another in the first position to an angled orientation relative to one another in the second position.

5. The push-in implant of claim 1 , wherein said blocker has an upper surface, a lower surface, and side surfaces as defined when said blocker is positioned to increase the height of said implant, said side surfaces intersecting said upper and said lower surfaces at two pairs of diametrically opposed junctions.

6. The push-in implant of claim 5 , wherein said two pairs of diametrically opposed junctions are a pair of diametrically opposed corners and a pair of diametrically opposed arcs.

7. The push-in implant of claim 6 , wherein said two diametrically opposed arcs are each of the same radius.

8. The push-in implant of claim 7 , wherein the distance across said two diametrically opposed arcs generally approximates the distance between said upper and lower surfaces of said blocker.

9. The push-in implant of claim 1 , wherein said upper and lower members have a rotational articulation therebetween adjacent one of said proximal end and said distal end of said upper and lower members.

10. The push-in implant of claim 1 , wherein said implant has an interior, at least one of said upper and lower surfaces has a screw hole passing therethrough adapted to receive a screw passing from said interior of said implant into one of the adjacent bone masses.

11. The push-in implant of claim 1 , further comprising at least a portion of a bone-engaging projection adapted for linear insertion formed on the exterior of each of said upper and lower surfaces for penetrably engaging the adjacent bone masses.

12. The push-in implant of claim 11 , wherein said bone-engaging projection is selected from one of a ratchet, a surface roughening, and a knurling.

13. The push-in implant of claim 1 , in combination with a bone growth promoting material.

14. The push-in implant of claim 13 , wherein said bone growth promoting material is selected from one of bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

15. The push-in implant of claim 1 , wherein said distal ends of said upper and lower members are symmetrical from side to side.

16. The push-in implant of claim 1 , wherein said distal ends of said upper and lower members are asymmetrical from side to side.

17. A push-in orthopedic implant for linear insertion at least in part between two adjacent bone masses, said implant comprising:

an upper member having an upper surface adapted for placement toward and into contact with one of the adjacent bone masses, said upper surface being non-arcuate along a substantial portion of the length of said implant, said upper surface having at least one opening adapted to communicate with one of the adjacent bone masses, said upper member having a proximal end and a distal end, and said upper member including a first track portion positioned adjacent one of said proximal and distal ends of said upper member;

a lower member having a lower surface adapted for placement toward and into contact with the other of the adjacent bone masses, said lower surface being non-arcuate along a substantial portion of the length of said implant, said lower surface having at least one opening adapted to communicate with the other of the adjacent bone masses, said openings of said upper and lower surfaces being in communication with one another and adapted for permitting for the growth of bone from adjacent bone mass to adjacent bone mass through said implant, said lower member having a proximal end and a distal end corresponding to said proximal end and said distal end of said upper member, respectively, and said lower member including a second track portion positioned adjacent one of said proximal and distal ends of said lower member, the position of said second track portion corresponding to the position of said first track portion, said upper and lower members articulating therebetween adjacent one of said proximal ends and said distal ends of said upper and lower members and allowing for expansion of the height of said implant, said upper and lower members having a first position relative to one another allowing for a collapsed implant height and a second position relative to one another allowing for an increased height, and said upper and lower members adapted to interlock with one another to stop said upper and lower members from being moved apart from one another more than a predetermined distance;

at least one expander positioned in said first and second track portions, said first and second track portions adapted to restrain movement of said expander along the length of said implant, said expander adapted to expand said upper and lower members from the first position to the second position when moved from an expander insertion position to a final deployed expander position, said expander being adapted to cooperatively engage and hold at least a portion of said upper and lower members apart so as to maintain the increased height of said implant and resist the collapse of said implant to the collapsed implant height when said implant is in a final deployed position, said expander having a depth, a first height corresponding to the height of said expander when said implant is initially inserted between the adjacent bone masses, and a second height corresponding to the height of said expander when said expander is rotated into a final deployed position to increase the height of said implant, said second height of said expander being greater than said first height of said expander, said first height and said second height having an approximately perpendicular relationship, said first height and said second height each being greater than said depth; and

a hollow defined between said upper and lower members from adjacent said proximal end to adjacent said distal end in communication with said openings in each of said upper and lower surfaces, said hollow being adapted to receive fusion-promoting substances, and said hollow being unobstructed by said blocker.

18. The push-in implant of claim 17 , wherein said implant has a constant width in both the first position and the second position.

19. The push-in implant of claim 17 , wherein said implant has side walls and said expander does not contact said side walls when said implant is in the final deployed position.

20. The push-in implant of claim 17 , wherein said expander moves said upper and lower surfaces of said upper and lower members from one of a parallel orientation and an angled orientation relative to one another in the first position to an angled orientation relative to one another in the second position.

21. The push-in implant of claim 17 , wherein said expander has an upper surface, a lower surface, and side surfaces as defined when said expander is positioned to increase the height of said implant, said side surfaces intersecting said upper and said lower surfaces at two pairs of diametrically opposed junctions.

22. The push-in implant of claim 21 , wherein said two pairs of diametrically opposed junctions are a pair of diametrically opposed corners and a pair of diametrically opposed arcs.

23. The push-in implant of claim 22 , wherein said two diametrically opposed arcs are each of the same radius.

24. The push-in implant of claim 23 , wherein the distance across said two diametrically opposed arcs generally approximates the distance between said upper and lower surfaces of said expander.

25. The push-in implant of claim 17 , wherein said upper and lower members have a rotational articulation therebetween adjacent one of said proximal end and said distal end of said upper and lower members.

26. The push-in implant of claim 17 , wherein said implant has an interior, at least one of said upper and lower surfaces has a screw hole passing therethrough adapted to receive a screw passing from said interior of said implant into one of the adjacent bone masses.

27. The push-in implant of claim 17 , further comprising at least a portion of a bone-engaging projection adapted for linear insertion formed on the exterior of each of said upper and lower surfaces for penetrably engaging the adjacent bone masses.

28. The push-in implant of claim 27 , wherein said bone-engaging projection is selected from one of a ratchet, a surface roughening, and a knurling.

29. The push-in implant of claim 17 , in combination with a bone growth promoting material.

30. The push-in implant of claim 29 , wherein said bone growth promoting material is selected from one of bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

31. The push-in implant of claim 17 , wherein said distal ends of said upper and lower members are symmetrical from side to side.

32. The push-in implant of claim 17 , wherein said distal ends of said upper and lower members are asymmetrical from side to side.