Conditioned Pain Modulation in Localized vs Widespread Chronic Low Back Pain

Study Overview
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Brief Summary
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This study aims to compare function of the body's endogenous pain modulation system between people with localized low back pain versus widespread body pain. Endogenous pain modulation refers to the body's natural ability to inhibit one pain stimulus by applying a second pain stimulus. This study will assess pain inhibition by measuring pressure pain thresholds at the low back before and during cold water hand immersion. The researchers hypothesize that those with widespread body pain will have worse functioning of pain inhibition compared to those with localized low back pain only. The results may provide insights into personalized chronic pain management approaches.

Detailed Description
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Chronic low back pain (CLBP) is highly prevalent worldwide. Impairments in conditioned pain modulation (CPM) have been documented in CLBP populations. CPM refers to endogenous pain inhibition, where one noxious stimulus inhibits pain from a second noxious stimulus. This relies on descending inhibitory pathways. However, it is unknown whether CPM alterations differ between individuals with localized versus widespread mechanical pain hypersensitivity. The aim of this cross-sectional quantitative sensory testing study is to compare CPM function between localized and widespread CLBP subgroups. A sample of 75 adults with CLBP of at least 3 months duration will be recruited from a chronic pain clinic. Based on pressure pain threshold mapping at the low back and distal sites, participants will be classified as having localized or widespread mechanical hyperalgesia.

Official Title
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Determining if Conditioned Pain Modulation Differs Between Individuals With Localized Versus Widespread Mechanical Pain Hypersensitivity in Chronic Low Back Pain

Conditions
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Chronic Low-back Pain

Intervention / Treatment
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* Other: Localized vs Widespread Mechanical Pain Hypersensitivity


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ages 18-60 years Chronic LBP >3 months Average LBP intensity ≥4/10 Exclusion Criteria: Known LBP pathologies Previous lumbar surgery Neuropathic LBP Comorbid generalized pain conditions

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Localized CLBP<br>Chronic low back pain >3 months with localized pressure pain hyperalgesia | Other: Localized vs Widespread Mechanical Pain Hypersensitivity<br>* Based on pressure pain threshold mapping, participants will be classified as having either localized mechanical pain hyperalgesia (hyperalgesia limited to the lumbosacral region) or widespread mechanical pain hyperalgesia (hyperalgesia extending beyond the lumbosacral region).<br>|
| Widespread CLBP<br>Chronic low back pain >3 months with widespread pressure pain hyperalgesia | Other: Localized vs Widespread Mechanical Pain Hypersensitivity<br>* Based on pressure pain threshold mapping, participants will be classified as having either localized mechanical pain hyperalgesia (hyperalgesia limited to the lumbosacral region) or widespread mechanical pain hyperalgesia (hyperalgesia extending beyond the lumbosacral region).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Conditioned Pain Modulation | Percent change in pressure pain threshold at the lumbar region during cold water hand immersion conditioning stimulus compared to baseline pressure pain threshold at the lumbar region without the conditioning stimulus. | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pressure Pain Thresholds | Pressure pain thresholds measured in kg/cm2 using a pressure algometer at the lumbar spine and distal sites including the upper trapezius and thumbnail. | baseline |