The accuracy of surface measurement for motion analysis of osteoporotic thoracolumbar spine.

The surface method of measuring the movements of lower thoracic and lumbar spine with osteoporosis using Fastrak® was examined for validity. There is an increasing awareness of the health risks of exposure to radiation associated with repeated radiographic assessment of spinal curvature and spinal movements. As a skin-surface measurement device, Fastrak® was employed to study the effect of low bone mineral density on spine motion. However, the reliability and validity of data recorded has not been established. The purpose of this study was to develop a methodology to determine the accuracy of the surface measurement device when it is applied to the motion analysis of osteoporotic spine. The results obtained indicated that the rotation angle of lumbar and lower thoracic spine could be predicted with acceptable accuracy from the data collected from skin-mounted sensors, while the prediction error of translational movements were not acceptable.