Doctoral Thesis
The role of lumbar multifidus muscle morphology in relation to clinical outcomes in patients with low back pain or low back-related leg pain: A prospective cohort study
Doctor of Philosophy (PhD), Murdoch University
2022
Abstract
Globally, low back pain (LBP) causes more disability than any other condition. The roles of degenerative changes in the spine and related musculature in LBP are unclear. This thesis investigated the relationships between lumbar multifidus muscle (LMM) morphology, spinal pathology, and the clinical outcomes experienced by people with LBP in linked studies comprising a systematic review, MRI measurement evaluation, and cross-sectional and longitudinal observational studies.
Using systematic review methods, I synthesized the evidence of relations between lumbar neurocompressive disorders and multifidus morphology and found that disc herniations and facet arthrosis were related to altered morphology in patients with chronic radiculopathy. However, the limitations of methods used to assess muscle morphology made between-study comparisons challenging.
In a subsequent methodological study, I evaluated the concurrent validity of T1- and T2- weighted MRI sequences, finding these sequences can be used interchangeably for measuring LMM morphology. I also developed and evaluated the reliability of a new method of measuring multifidus composition, showing excellent intra-rater reliability.
In two observational studies, I explored the cross-sectional associations between individual and aggregate degenerative lumbar findings and multifidus quality, and between multifidus quality and LBP-related clinical outcomes in cohorts of patients presenting to secondary care. Disc degeneration, facet arthrosis, Modic type 2 changes, and an increased number of pathologies were associated with lower multifidus quality. Patients with higher multifidus quality reported lower levels of disability and leg pain.
Finally, in a longitudinal study of patients receiving conservative treatment for LBP, I examined the effect of degenerative spinal pathology and LMM quality on 12-month clinical outcomes. Patients with lower multifidus quality and a greater number of spinal pathologies reported higher levels of leg pain intensity. Effect decomposition revealed that the effect of spinal pathology on leg pain was not mediated by multifidus quality. The relations between spinal degeneration, multifidus degeneration, and LBP-related outcomes appear complex and may include independent pathways. The findings of this thesis will help inform future studies aimed at understanding the degenerative changes experienced by people with LBP.
Details
- Title
- The role of lumbar multifidus muscle morphology in relation to clinical outcomes in patients with low back pain or low back-related leg pain: A prospective cohort study
- Authors/Creators
- Jeffrey R Cooley
- Contributors
- Belinda Brown (Supervisor) - Murdoch University, Centre for Healthy AgeingJean Theroux (Supervisor)Jeffrey Hebert (Supervisor)
- Awarding Institution
- Murdoch University; Doctor of Philosophy (PhD)
- Identifiers
- 991005548667707891
- Murdoch Affiliation
- College of Science, Health, Engineering and Education
- Resource Type
- Doctoral Thesis
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