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

Study Design: Structural properties of vertebrae with simulated defects were measured from computed tomography data. Relations between structural properties and postfracture stability were tested using linear regressions.
Objectives: To determine whether the postfracture stability of lumbar and thoracic vertebrae can be predicted from noninvasive, prefracture measurements of structural properties.
Summary of Background Data: Sensitive and specific guidelines are needed that can predict fracture risk and spinal stability after pathologic fractures. Such guidelines may help determine whether treatment is needed to prevent neurologic complications. Simple measurements made from computed tomography data can predict the load-bearing capacity of intact vertebrae and vertebrae 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 postfracture stability were measured.
Results: Postfracture stability was linearly correlated with both failure load (r2 = 0.3-0.6) and axial rigidity (r2 = 0.3-0.6).
Conclusions: The postfracture stability of three-vertebrae segments with simulated defects was modestly related to noninvasively measured, prefracture structural properties.