CHARACTERIZATION OF LUMBAR-LEVEL SPINAL FUSION ON THE WHOLE HUMAN SPINE UNDER VIBRATIONS

In the United States alone, 12-15% of the population will visit their physician for back pain problems each year, creating a direct annual cost of nearly $40 billion. Pain in the spine may be associated with spinal instability and intervertebral disc (IVD) degeneration. The causes of disc degeneration are not completely understood, but have been thought to be linked to excessive loading conditions and whole body vibrations. Patients not responding to non-operative treatment may be considered for surgical fusion. Vibrations of the spine near its resonant frequency are more likely to lead to spinal injury and subsequent pain. These vibrations may result from prolonged exposure to mechanical vibrations, for example from riding in vehicles. Little is understood about the effect of spine pathologies or treatment techniques on this frequency. While fusion procedure may aid in stabilizing the spine, it may also lead to changes in spine biomechanics. A high fidelity anatomically accurate whole spine finite element model was developed and utilized to examine vibration in the spine using modal analysis. Vibration modes and resonant frequencies were obtained in the healthy spine along with cases of lumbar spine disc degeneration and fusion at several levels, including L4-L5, L3-L5, L5-S, L4-S, and L3-S.