Stereotactic analysis of spinal motion segments

The 3D image space defined from the 3-space of CT image data is capable of accurately identifying the anatomy of vertebral bodies. With the recent advances made by highly accurate stereotactic systems, a means of consistently identifying six markers on a vertebral body was implemented and subsequent 3D measurements were ascertained. Three points were used to form two vectors on each body. In turn, the cross product from these two vectors resulted in a third vector orthogonal to the two. This was done for both bodies in the spinal motion segment. The spines were then implanted with two threaded intervertebral fusion cages and the measurements were repeated. The difference between the original lordosis and final lordosis is the reported restored lordosis. Six human cadaver lumbar spines were used to evaluate the restored lordosis through this technique. The final lordosis was found to be statistically larger than the original lordosis and the restored lordosis from these intervertebral cages were found to be 5.8°±3.6