Comparison of In Vivo and In Vitro Adjacent Segment Motion After Lumbar Fusion

Abstract

Under "load" control, in vitro facet motion did not significantly change after immobilization, whereas under "displacement" control, the facet motion significantly increased from 2.2 +/- 0.4 mm to 4.1 +/- 0.6 mm. Post-instrumentation, in vivo L2-L3 facet motion increased significantly. This change in vivo related better to the changes seen in the in vitro "displacement" control test than to the in vitro "load" control test.