Trial intervertebral distraction spacers

1. An orthopedic spacer device for positioning between adjacent vertebral bones, the device comprising:

a cylindrical spacer body having a longitudinal axis and a bore having a longitudinal axis extending coaxially with the spacer body longitudinal axis through upper and lower surfaces thereof, the upper and lower surfaces each having a circumference;

at least two relative angle designation marks disposed on said at least one of said upper and lower surfaces, said angle designation marks being remote from one another at a predetermined spatial distance about the circumference of at least one of said upper and lower surfaces such that once said spacer body is inserted between adjacent vertebral bones and the spacer body is rotated, a rotational angle of the spacer body relative to a known reference is determinable by comparing the rotation of said angle designation marks about said longitudinal axis of the spacer body; and

an annular groove situated between the tapered upper and lower surfaces of said spacer body into which a manipulation tool is seatable, said groove being of a constant width such that said spacer body may rotate freely with respect to said manipulation tool.

2. The orthopedic spacer device as set forth in claim 1 , wherein the spacer body includes beveled edges that facilitate an application of a desired spreading force to adjacent vertebral bones.

3. The orthopedic spacer device as set forth in claim 1 , wherein the spacer body includes beveled upper and lower edges that facilitate an application of a desired spreading force to adjacent vertebral bones.

4. The orthopedic spacer device as set forth in claim 1 , wherein each of the upper and lower surfaces includes a substantially flat central portion.

5. The orthopedic spacer device as set forth in claim 1 , wherein each of the upper and lower surfaces are tapered.

6. The orthopedic spacer device as set forth in claim 1 , wherein each of the upper and lower surfaces are non-parallel.

7. An intervertebral spacer set, each spacer in the set adapted for positioning between adjacent vertebral bones, the spacer set comprising:

a plurality of intervertebral spacers, each having a unique axial thickness and a cylindrical external surface;

at least two relative angle designation marks disposed circumferentially on said external surface, said angle designation marks being remote from one another at a predetermined spatial distance such that once each of said plurality of the intervertebral spacers is inserted between adjacent vertebral bones and rotated, a rotational angle of the spacer relative to a known reference is determinable by comparing the rotation of said angle designation marks; and

a groove formed in each spacer in the set, said groove defined by a trunk and a cylindrical flange at each end of the trunk, into which a manipulation tool is seatable, said groove being of a constant width such that each spacer may rotate freely with respect to said manipulation tool,

wherein each spacer in the set has a bore having a longitudinal axis through non-parallel upper and lower surfaces thereof, and the unique axial thickness of each spacer in the set increases sequentially from one spacer to another.

8. The intervertebral spacer set as set forth in claim 7 , wherein each of the upper and lower surfaces includes a substantially flat central portion.

9. The intervertebral spacer set as set forth in claim 7 , wherein each of the upper and lower surfaces are tapered.

10. An intervertebral spacer set, comprising:

a plurality of intervertebral spacers for positioning between adjacent vertebral bones, each intervertebral spacer including non-parallel upper and lower surfaces that provide a taper to each spacer and a bore having a longitudinal axis through the upper and lower surfaces,

wherein each spacer includes a circumferential radial edge having disposed thereon at least two relative angle designation marks, said angle designation marks being remote from one another at a predetermined spatial distance about said circumferential radial edge such that once one of said intervertebral spacers is inserted between adjacent vertebral bones and rotated, a rotational angle of the spacer relative to a known reference is determinable by comparing the rotation of said angle designation marks,

wherein each intervertebral spacer includes an engagement locus that couples with a manipulation tool,

wherein the engagement locus comprises an annular groove having a circumference around which the manipulation tool is seatable,

wherein the groove comprises a constant width, such that each intervertebral spacer may rotate freely within the manipulation tool, and

wherein each intervertebral spacer has a different taper angle from each other spacer.