| In order to promote solid fusion across a decompressed spinal segment, inter-body spacers/cages are used with and without posterior instrumentation to provide an initial "rigid" fixation of the segment. Inter-body spacers (cages) of various shapes (e.g., rectangular, cylindrical) and materials are currently available on the market. Important factors affecting the biomechanics of the fused segment are (i) cage shape and placement, (ii) cage material property, (iii) surgical approach used---posterior vs. antero lateral, (iv) cage with additional instrumentation. The objective of this study is to address change in the stability and stress patterns associated with the various factors described above.; A cadaveric study using established protocols and a finite element (FE) study were conducted. For the cadaveric study, nine fresh ligamentous lumbar spine specimens (L1-S2) were radiographed out of which six specimens were prepared for testing by fixing a base to the sacrum and a loading frame to the top-most vertebra. (Abstract shortened by UMI.)... |
