Biomechanical design of load simulation in multiple spinal segments]

Multisegmental biomechanical studies on the lumbar spine are steadily increasing in importance. Only in this way can we acquire knowledge about the physiological behaviour of the entire lumbar spine. Furthermore, these studies allow us to analyse in vitro the biomechanics of manipulated lumbar spines after various surgical operations on the spine. A load simulator was developed to investigate multisegmental lumbar spine mobility, and its function was investigated in an initial study on 19 fresh--frozen specimens of human lumbar spine. After x-ray examination and determination of the bone mineral density, the specimens were loaded up to 10 Nm in the automatic electromechanical loading system under flexion/extension, lateral bending and axial rotation. An ultrasound-based motion analysis system was used to measure the displacements of the vertebrae involved.