A quantitative biomechanical analysis of mechanism of pain alteration in 4 cases of low back pain.
To investigate the contributions of a number of biomechanical factors associated with pain alteration.
Some clinicians use mechanically based manual interventions in attempt to reduce low back pain. However, the mechanism of pain alteration remains unknown.
A 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.
Using 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.
Immediate 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.
Reducing a patient's pain immediately is possible with changes in muscle-activation/stiffness and altering movement patterns. However, these changes must be “tuned” to the individual.
From the Spine Biomechanics Laboratory, Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada.
Address correspondence and reprint requests to Stuart M. McGill, PhD, Faculty of Applied Health Sciences, Department of Kinesiology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada; E-mail: email@example.com
Acknowledgment date: April 5, 2012. Revision date: June 4, 2012. Acceptance date: July 28, 2012.
The manuscript submitted does not contain information about medical device(s)/drug(s).
Natural Sciences and Engineering Research Council of Canada grant funds were received to support this work.
No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.