Postfracture instability of vertebrae with simulated defects can be predicted from computed tomography data

Study Design. Structural properties of vertebrae with simulated defects wer e measured from computed tomography data. Relations between structural prop erties and postfracture stability were tested using linear regressions. Objectives. To determine whether the postfracture stability of lumbar and t horacic vertebrae can be predicted from noninvasive, prefracture measuremen ts of structural properties. Summary of Background Data. Sensitive and specific guidelines are needed th at can predict fracture risk and spinal stability after pathologic fracture s. Such guidelines may help determine whether treatment is needed to preven t neurologic complications. Simple measurements made from computed tomograp hy data can predict the load-bearing capacity of intact vertebrae and verte brae with simulated and actual metastatic defects. It is not known whether these same measurements can also predict postfracture stability. Method. Simulated metastatic defects were created in human three-vertebrae segments from the lumbar and thoracic spine. Axial rigidity was calculated from quantitative computed tomography data, and failure load and postfractu re stability were measured. Results. Postfracture stability was linearly correlated with both failure l oad (r(2) = 0.3-0.6) and axial rigidity (r(2) = 0.3-0.6). Conclusions. The postfracture stability of three-vertebrae segments with si mulated defects was modestly related to noninvasively measured, prefracture structural properties.