Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Department of Rehabilitation Sciences | en_US |
| dc.contributor.advisor | Wong, Arnold (RS) | en_US |
| dc.contributor.advisor | Pang, Marco (RS) | en_US |
| dc.contributor.advisor | Ng, Joseph (RS) | en_US |
| dc.creator | Pinto, Sabina Margaret | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/13067 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | The relationship between back pain and the morphology and function of the lumbar multifidus muscle in individuals with and without low back pain | en_US |
| dcterms.abstract | Background: Lumbar multifidus muscle (LMM) is thought to be highly related to chronic low back pain (CLBP), as it serves as a spinal stabilizer. Many people with CLBP are characterized by LMM atrophy and/or intramuscular fatty infiltration on magnetic resonance images, decreased percent thickness change during contraction under ultrasound imaging, or compromised LMM proprioception, which may indicate suboptimal LMM function in these individuals. While many factors (e.g., demographics, psychological variables, insomnia, and spinal phenotypes) may also confound the association between LMM and clinical outcomes (pain intensity and disability) in people with CLBP, there was a paucity of research that considered these confounders in exploring the association between LMM characteristics and CLBP. Importantly, it remains unclear whether aberrant changes in LMM characteristics are the cause or consequence of CLBP. If LMM dysfunction is related to the development or maintenance of CLBP, the improvements of LMM morphometry or function following interventions (especially motor control exercise) would be associated with the corresponding changes in pain or disability in these people. | en_US |
| dcterms.abstract | Objectives: The aims of this work were to: (1) summarize the evidence regarding the effectiveness of motor control exercise (MCE) in modifying LMM morphometry and reducing pain and the temporal associations between post-MCE changes in LMM and the clinical outcomes in people with low back pain (LBP); (2) determine whether LMM proprioception differed between people with and without CLBP at different age ranges that had never been investigated in prior research; (3) quantify the associations between LMM morphometry and function with pain intensity and disability in people with CLBP after controlling for confounders such as demographics, psychological factors, sleep disturbances and spinal phenotypes at baseline; and (4) identify baseline factors that could predict pain intensity and LBP-related disability in individuals with and without non-specific CLBP at the 2-year follow up. | en_US |
| dcterms.abstract | Methods: To achieve objective #1, a systematic review was conducted to comprehensively summarize the relevant evidence. For objectives #2, 3, and 4, a 2-year prospective study was conducted. At baseline, participants with CLBP (n=70) were recruited from a tertiary referral centre for spinal pathologies and asymptomatic individuals (n=67) were recruited from a university campus. All participants completed a battery of questionnaires, performed some physical tests (including lumbar proprioception and reposition tests, ultrasonography to evaluate LMM thickness and stiffness) and underwent lumbar magnetic resonance imaging to evaluate spinal phenotypes, LMM total cross-sectional area or volume and LMM percent lean muscle volume. All participants also provided their pain intensity and LBP-related disability levels every 6 months through online questionnaires. At the 2-year follow-up, participants [CLBP (n=43), asymptomatic (n=41)] repeated questionnaires, physical tests and medical imaging. | en_US |
| dcterms.abstract | Results: The systematic review found that MCE can change LMM dimensions in people CLBP. However, these changes were unrelated to the corresponding improvements in clinical outcomes (pain intensity and LBP-related disability). The baseline data of the prospective study found that compared to young people with CLBP (18 to 44 years), young people with CLBP and middle-aged (45-65 years) people with or without CLBP demonstrated inferior lumbar proprioceptive reweighting capability, indicating that CLBP compromised young people’s lumbar proprioceptive reweighting capacity, but age-related deterioration in central and peripheral processing of lumbar proprioceptive signals become more dominant from middle-age onward. The B-mode ultrasonography found that people with CLBP had significantly smaller percent thickness changes of LMM at the L4/5 level than asymptomatic controls. However, the percent thickness change of LMM at the L4/5 level was unrelated to LBP intensity or LBP-related disability in individuals with CLBP after adjusting for other self-reported factors. In particular, fear-avoidance belief questionnaire work subscale scores and insomnia severity index scores together explained 24% of LBP intensity in people with CLBP, while fear-avoidance belief questionnaire total scores alone explained 34% of variance of LBP-related disability in people with CLBP. The lumbar magnetic resonance imaging found that although people with CLBP had significantly more fatty infiltration in LMM, their LMM morphometric parameters were unrelated to LBP intensity or LBP-related disability after considering demographics, psychological factors, insomnia, and spinal phenotypes. The baseline data did not predict the pain intensity or LBP-related disability at follow-up time points (6 months, 12 months). The follow-up study at 2 years revealed that baseline fear-avoidance beliefs –Work scores predicted pain intensity at 2 years in people with CLBP, while baseline pain-catastrophizing scale-helplessness and insomnia predicted LBP-related disability (Roland-Morris Disability score) at 2 years in people with CLBP. The temporal changes in LMM characteristics over the two year-period were unrelated to clinical outcomes at the 2-year follow-up. Because none of the asymptomatic participants developed CLBP at the 2-year follow-up, it was impossible to determine whether baseline LMM characteristics or other factors could predict the development of CLBP. | en_US |
| dcterms.abstract | Conclusion: Although it is believed that intramuscular fatty infiltration in LMM is higher in people with CLBP as compared to healthy people, which might be related to clinical outcomes, my systematic review has found that any post-MCE changes in LMM characteristics were unrelated to CLBP improvements. My empirical study is the first prospective study to comprehensively investigate the relative influences of LMM characteristics on LBP and LBP-related disability at different time points in people with and without CLBP after considering spinal phenotypes, demographic data, and psychosocial factors. The study revealed that aberrant changes in morphometry or function LMM at a given time point were unrelated to the clinical outcomes (LBP intensity and LBP-related disability) after considering spinal phenotypes, psychological factors, and insomnia. Further, baseline LMM characteristics in people with CLBP did not predict their clinical outcomes at the 2-year follow-up. Instead, baseline fear-avoidance belief scores predict recurrent pain intensity, while baseline pain catastrophizing and insomnia predict LBP-related disability in individuals with CLBP at the 2-year follow-up. Taken together, my findings suggest that the LMM morphometry or function, as well as spinal phenotypes appeared to be less relevant to LBP intensity or LBP-related disability after considering various psychosocial factors. Clinicians should use validated screening tools to identify people with CLBP with strong fear-avoidance beliefs, pain catastrophizing and sleep disorders so that appropriate treatments (e.g., cognitive behavioural therapy for sleep or pain) can be administered timely. Although the current findings do not support LMM to play a crucial role in clinical symptoms or disability in people with CLBP, it is possible that a subgroup of people with more severe deterioration in LMM morphometry or function may predict long-term clinical outcomes in individuals with and without CLBP. Future large-scale prospective studies with long-term follow-ups and subgroup analyses are warranted to clarify this association. | en_US |
| dcterms.extent | xxxii, 237 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2024 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.accessRights | open access | en_US |
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