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The mechanism underlying differential biomechanical and clinical responses in patients with low back pain following spinal manipulative therapy Open Access


Other title
spinal stiffness
spinal manipulative therapy
experimental pain
low back pain
disc diffusion
lumbar multifidus
Type of item
Degree grantor

Author or creator
Supervisor and department
Examining committee member and department
Dhillon, Sukhvinder (Radiology and Diagnostic Imaging)
Parent, Eric (Physical Therapy)
Adeeb, Samer (Civil and Environmental Engineering)
Prasad, Narasimha (Mathematical and Statistical Sciences)
Hartvigsen, Jan (Sports Science and Clinical Biomechanics, University of Southern Denmark)
Rehabilitation Science
Date accepted
Graduation date
Doctor of Philosophy
Degree level
Background: Spinal manipulative therapy (SMT) is a common intervention for nonspecific low back pain (LBP). Various studies have shown independently that LBP patients who respond favorably to SMT differ from those non-responders in terms of baseline or post-SMT changes in physical characteristics. These physical characteristics include spinal stiffness, lumbar multifidus function, and/or disc diffusion. Unfortunately, prior to this dissertation, no research has used a unified methodology to investigate various physical characteristics in a single cohort of LBP individuals or to compare these physical characteristics with the data from untreated LBP or asymptomatic controls. Objective: To quantify whether physical characteristics of SMT responders and non-responders as defined by three different dichotomization strategies differ from those of untreated LBP and asymptomatic controls. Methods: Two systematic reviews and three clinical studies (a reliability experiment, a pain induction study, and a non-randomized clinical trial) were conducted. In the clinical studies, the LBP participants who received SMT were dichotomized into responders and non-responders based on: 1) a clinical prediction rule, 2) self-reported pain scores or 3) self-reported disability on Day 7. Results: The two systematic reviews found conflicting evidence regarding the relation between baseline or temporal changes in morphometry/function of lumbar multifidus and LBP outcomes following various conservative treatments. The reviews also revealed conflicting evidence regarding the baseline function of transversus abdominis in predicting LBP outcomes. There was strong evidence against a temporal relation between changes in the morphometry/function of transversus abdominis during conservative treatments and changes in LBP symptoms. Transversus abdominis was included in the reviews because multifidus was proposed to work closely with transversus abdominis to maintain spinal stability, which might be related to LBP. Excellent intra-rater/intra-observer reliability was found for all the measurements adopted in clinical studies. These measurements included spinal degeneration grading and intervertebral disc diffusion measurements on lumbar magnetic resonance images, spinal stiffness measurements, and lumbar multifidus thickness assessments. Of the clinical studies, the pain induction study revealed that experimental pain caused temporary increases in spinal stiffness and concurrent trunk muscle activity during the stiffness test, but temporary decreases in lumbar multifidus thickness ratios (a proxy of mulitifdus function during volitional contraction). Of the clinical studies, the imaging trial highlighted that SMT non-responders as defined by self-reported pain or disability scores on Day 7 tended to have higher prevalence of severe facet joint degeneration and poorer caudal lumbar disc diffusion at baseline as compared to the responders and untreated LBP controls. Conversely, the responders defined by self-reported pain or disability demonstrated positive post-SMT changes in water diffusion across all the lumbar discs as compared to the non-responders or untreated LBP controls. In the clinical studies, all the SMT responders regardless of dichotomization strategies consistently displayed immediate and/or sustained decreases in spinal stiffness and increases in lumbar multifidus function during volitional contraction. No such change was observed in the non-responders or asymptomatic controls. Conclusion:. Consistent physical changes within SMT responders imply that SMT imparts a multidimensional effect which includes alterations in biomechanics (stiffness, disc diffusion), neurophysiology (muscle function) and pain, but only in subjects who are receptive to SMT (less degenerative change). As such, this work provides a foundation to investigate the origin of the heterogeneous nature of LBP, the diversity of therapeutic mechanisms and how aligning these characteristics may optimize clinical and societal outcomes.
This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for the purpose of private, scholarly or scientific research. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
Citation for previous publication
Wong AY, Parent EC, Funabashi M, Stanton TR, Kawchuk GN. Do various baseline characteristics of transversus abdominis and lumbar multifidus predict clinical outcomes in nonspecific low back pain? A systematic review. Pain 2013 154(12):2589-2602.Wong AY, Parent EC, Funabashi M, Kawchuk GN. Do changes in transversus abdominis and lumbar multifidus during conservative treatment explain changes in clinical outcomes related to nonspecific low back pain? A systematic review. J Pain 2014;15:377:e1-35.Wong AY, Kawchuk G, Parent E, Prasad N. Within- and between-day reliability of spinal stiffness measurements obtained using a computer controlled mechanical indenter in individuals with and without low back pain. Man Ther 2013;18:395-402.Wong AY, Parent EC, Kawchuk GN. Reliability of 2 ultrasonic imaging analysis methods in quantifying lumbar multifidus thickness. J Orthop Sports Phys Ther 2013;43(4):251-262.

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