New method for the non-invasive three-dimensional measurement of human back movement.

A new method for the non-invasive three-dimensional measurement of human lumbar movement is described. The electro-magnetic 3space Isotrak system was found to be accurate and reliable, having a total r.m.s. error for rotations of less than o·2°. The system was able to produce consistent plots of subjects' movement patterns and it is proposed that this system should be evaluated in respect of its discriminatory and predictive potential in clinical studies of low back disorders. It may then become a useful tool in the routine clinical assessment of patients with spinal disorders, providing a complete quantification of back kinematics quickly and efficiently.