Neuroimaging of Spinal Instability

The human spine is a complex biomechanical system composed of multiple articular structures controlled by muscles. Spine diseases are frequently related to a loss of stability. Dedicated imaging protocols have been developed to evaluate spinal instability. Dynamic radiography with lumbar flexion-extension is used most often; however, in traumatic instability, computerized tomography provides better diagnostic accuracy for fracture detection. Novel technology improvements allow acquisition of dynamic MRI with axial load or upright standing techniques to simulate a more pathologic condition compared with conventional supine scans. This article reviews the basic concepts of spinal instability and describes the role of different imaging techniques in its assessment.