ABSTRACT
To optimise the use of spinal manipulation for maximum effectiveness and safety, it is necessary to investigate the kinematics and dynamics of current procedures. The objective of our investigations is to model the responses to the slow application of manipulative force to the bony prominences in the midline of a prone subject. A finite element (FE) model was developed to allow the prediction of forces and deformations in the various anatomical elements of the spine, ribcage and pelvis. The validity of the modelling procedure was examined by comparing the model’s predictions of behaviour with the responses demonstrated by living subjects. Studies of the average responses to low lumbar forces showed that the model was a good predictor of the observed behaviour of living subjects. To more broadly examine the model validity, an investigation was carried out to evaluate the degree to which the model could predict variations in mechanical behaviour between 20 healthy individuals. Because of the clinical relevance, the prediction of responses to low lumbar forces (at L4) was the main focus of this experiment although the behaviour in response to forces at 4 other spinal locations (LI, T10, T7, T4) was also studied. In the case of the low lumbar (L4) forces, good correlation between model and living subjects was found (r=0.67), but at other locations the model showed substantially lower correlations with living subject data.
