The Role of Lumbar Multifidus Characteristics in the Development of Low Back Pain

Study Overview
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Brief Summary
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Low back pain (LBP) is a severe epidemic in the world. Despite its high prevalence, 90% of the cases have no identifiable cause. Approximately 44% of them experience recurrent LBP within one year and 10% of them develop chronic LBP that lasts for three months or more. Mechanically, the lumbar spine is unstable and requires spinal muscle to maintain spinal stability and to prevent injuries. Lumbar multifidus (LM) muscle is thought to be the major spinal stabilizer responsible for spinal stability and spinal proprioception. Prior studies have revealed that increased fat infiltration, atrophy or activation deficits of LM in patients with LBP as compared to asymptomatic individuals. Unfortunately, inconsistent findings have also been reported. Although prior research attempted to determine if abnormal LM characteristics can inform clinical decision-making, their results are limited because they only investigated a single LM characteristic at a time, which might not reflect the actual LM condition. Further, many studies adopted cross-sectional design that could not reveal the casual relations between abnormal LM characteristics and LBP. As such, the current study aims to identify specific LM characteristics that can predict new episode of LBP in asymptomatic individuals, and recurrent/chronic LBP in individuals with LBP at baseline.

Detailed Description
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Low back pain (LBP) is a severe epidemic in the world. Despite its high prevalence, 90% of the cases have no identifiable cause. While most people with LBP recover shortly after onset, approximately 44% of them experience recurrent LBP within one year and 10% of them develop chronic LBP that lasts for three months or more. Mechanically, the lumbar spine is unstable and requires spinal muscle to maintain spinal stability and to prevent injuries. Lumbar multifidus (LM) muscle is thought to be the major spinal stabilizer responsible for spinal stability and spinal proprioception. Different cross-sectional studies have revealed that increased fat infiltration, atrophy or activation deficits of LM in patients with LBP as compared to asymptomatic individuals. Research has shown that abnormal morphology or activation of LM is associated with LBP intensity/location, or LBP-related disability. Unfortunately, inconsistent findings have also been reported. Although prior research attempted to determine if abnormal LM characteristics can inform clinical decision-making, their results are limited because they only investigated a single LM characteristic at a time, which might not reflect the actual LM condition. Further, many studies adopted cross-sectional design that could not reveal the casual relations between abnormal LM characteristics and LBP. Given the above, the current study aims to identify specific LM characteristics that can predict new episode of LBP in asymptomatic individuals, and recurrent/chronic LBP in individuals with LBP at baseline.

Official Title
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The Role of Lumbar Multifidus Characteristics in the Development of Low Back Pain

Conditions
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Low Back Pain

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: aged 18 to 65 years Symptomatic participants should have LBP that requires medical consultation(s) in the last three months LBP intensity of at least 5 on the 11-point numeric pain rating scale at baseline (for symptomatic participants) Asymptomatic participants should be pain free at baseline, and should not have LBP in the last year nor LBP lasting more than a week in the last 3 years Exclusion Criteria: a history of neurological disease or vestibular impairment systemic inflammatory disease prior spinal surgery acute/chronic neuropathy or radiculopathy spinal infections/fractures/tumors, metabolic disorders, medical 'red flags'

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Low back pain group<br>Participants will be followed up over 2 years to monitor the course of low back pain | |
| Asymptomatic group<br>Participants will be followed up over 2 years to monitor the incidence and course of low back pain | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 11-point numeric pain rating scale (NPRS) for low back pain | The current pain intensity of each participant will be quantified by an 11-point NPRS, where 0 means no pain and 10 means the worst imaginable pain. | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Morphometry of lumbar multifidus | B-mode ultrasound imaging will be used to quantify morphometry of multifidus | 2 years | 
| Proprioception of lumbar multifidus | An established protocol to measure proprioception of lumbar multifidus | 2 years | 
| Stiffness of lumbar multifidus | Elastography will be used to measure lumbar multifidus stiffness | 2 years | 
| Fatty infiltration of lumbar multifidus | Magnetic resonance imaging will be used to quantify the fatty infiltration of multifidus | 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Low back pain, lumbar multifidus, Proprioception, Elastography, Magnetic resonance imaging