• Dianne M Ikeda and Stuart M McGill.
• Spine Biomechanics Laboratory, Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada.
• Spine. 2012 Nov 1;37(23):E1469-75.

Study DesignA quantitative biomechanical analysis of mechanism of pain alteration in 4 cases of low back pain.ObjectiveTo investigate the contributions of a number of biomechanical factors associated with pain alteration.Summary Of Background DataSome clinicians use mechanically based manual interventions in attempt to reduce low back pain. However, the mechanism of pain alteration remains unknown.MethodsA sample was formed with 4 patients with low back pain seeking consults for pain relief. All could produce "catches" of pain with movement. Manual interventions involving coached changes in motion and muscle activation attempted to reduce pain. Electromyographic and kinematic data were collected before and after intervention. These data were input to an anatomically detailed spine model that calculated muscle force, joint compression and shear, and spine stability.ResultsUsing a clinically significant criterion of pain reduction of 2 or more, 3 of 4 subjects reduced pain immediately upon the intervention. Using a change of 10% as a criterion for biological significance for kinematic and kinetic variables, each subject demonstrated a different reaction. For example, subject 1 demonstrated increased stability, subject 2 increased mediolateral shear, subject 3 increased mediolateral shear and decreased spine flexion, and subject 4 increased stability. The pain-reducing interventions required to obtain these results were also different for each individual.ConclusionImmediate pain reduction can be achieved by altering muscle-activation and movement patterns. However, the combination for optimal success seems to be different for every individual. Pain provocation tests help to "tune" the intervention. This also suggests that patient-classification schemes may need more refinement to address this heterogeneity.

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