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Sponsored by: |
University Hospital Inselspital, Berne |
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Information provided by: | University Hospital Inselspital, Berne |
ClinicalTrials.gov Identifier: | NCT00892411 |
Background. Patients with chronic low back pain display hyperexcitability of the central nervous system (central hypersensitivity). Such hypersensitivity may occur in the acute phase and represent a risk factor for the development of chronic pain.
Objective. To determine the prognostic value of central hypersensitivity for the development of chronic low back pain.
Design. Prospective cohort study.
Setting. Primary care.
Patients. 140 individuals with acute low back pain and no history of chronic pain.
Outcomes. Primary prognostic variable will be the pain tolerance threshold at the second toe (the pressure intensity at which a further increase in pressure is deemed intolerable). Exploratory secondary prognostic variables are measures of mechanisms related to central hypersensitivity: stimulus-specific hypersensitivity (pressure, electrical, heat and cold stimulation); tissue-specific hypersensitivity (skin vs. muscle stimulation); localized vs. widespread hypersensitivity; spinal cord modulation (electrophysiological measures of hypersensitivity and changes in receptive fields); modulation at brain level (descending modulation of nociceptive input and cortical plasticity). Clinical primary outcome will be the occurrence of chronic low back pain at follow-up.
Main analysis. The investigators will use least square logistic regression models to determine the association of central hypersensitivity with prognosis.
Relevance. An understanding of the prognostic value of central hypersensitivity may allow an early stratification for treatment of individuals at risk of developing chronic low back pain. Subgroups of patients may be selected for clinical trials on novel pharmacological approaches for the prevention and treatment of central hypersensitivity.
Condition | Intervention |
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Pain Measurement Low Back Pain |
Other: Assessment of parameters of central hypersensitivity Other: Spinal cord hyperexcitability Other: Descending modulation and cortical reorganization |
Study Type: | Observational |
Study Design: | Cohort, Prospective |
Official Title: | Prognostic Value of Measures of Central Hypersensitivity in Patients With Low Back Pain |
Estimated Enrollment: | 140 |
Study Start Date: | February 2009 |
Estimated Study Completion Date: | December 2010 |
Estimated Primary Completion Date: | December 2010 (Final data collection date for primary outcome measure) |
Groups/Cohorts | Assigned Interventions |
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1
Evaluation of spinal cord hyperexcitability, temporal summation and spinal reorganization
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Other: Assessment of parameters of central hypersensitivity
Sensory tests, pain thresholds, nociceptive reflexes, EEG.
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2
Evaluation of descending modulation and cortical reorganization
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Other: Spinal cord hyperexcitability
Sensory tests and spinal reflexes
Other: Descending modulation and cortical reorganization
Sensory tests and EEG.
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Background
Prolonged afferent nociceptive input induces an increase in the excitability of central sensory neurons and plasticity changes that cause hyperexcitability of the central nervous system (central hypersensitivity. The hyperexcitable central nervous system amplifies the nociceptive signal, thereby producing an exaggerated pain response even in the presence of limited tissue damage.
Using quantitative sensory tests, central hypersensitivity has been detected in different chronic musculoskeletal pain syndromes. Patients with chronic low back pain display increased pain sensitivity and enlargement of the areas of referred pain after stimulation of tissues around and distant from the site of pain (i.e. the leg or the thumb), suggesting that widespread central hypersensitivity is associated with this condition. Functional reorganization of the cortex has been detected in different pain conditions, including low back pain. Using equal levels of sensory stimulation in patients and pain-free controls, patients with chronic low back pain showed more extensive patterns of neuronal activation in pain-related cortical areas. An investigation on patients after a whiplash injury found that those patients with persistent moderate or severe symptoms at 6 months had displayed, soon after injury, widespread hypersensitivity. Therefore, central hypersensitivity may be an indicator of poor prognosis. An acute peripheral lesion may induce plasticity changes leading to central hypersensitivity in a subset of individuals. Such a hypersensitivity would facilitate the transition from acute to chronic pain and disability. This hypothesis has been investigated using a limited number of tests only in a limited number of individuals with whiplash injury, but not in any other condition.
Objective
To determine the prognostic value of different measures of mechanisms of central hypersensitivity in patients with acute low back pain.
Methods
140 consecutive Patients with acute low back pain, referred by general practice, will be studied prospectively. Primary prognostic variable will be the pain tolerance threshold at the second toe (the pressure intensity at which a further increase in pressure is deemed intolerable). Exploratory secondary prognostic variables are measures of mechanisms related to central hypersensitivity: stimulus-specific hypersensitivity (pressure, electrical, heat and cold stimulation); tissue-specific hypersensitivity (skin vs. muscle stimulation); localized vs. widespread hypersensitivity; spinal cord modulation (electrophysiological measures of hypersensitivity and changes in receptive fields); modulation at brain level (descending modulation of nociceptive input and cortical plasticity). Clinical primary outcome will be the occurrence of chronic low back pain at follow-up. We will use least square logistic regression models to determine the association of central hypersensitivity with prognosis.
Ages Eligible for Study: | 18 Years to 80 Years |
Genders Eligible for Study: | Both |
Accepts Healthy Volunteers: | No |
Sampling Method: | Probability Sample |
Patients with acute low back pain referred from primary care.
Inclusion Criteria:
Exclusion Criteria
Contact: Alban Neziri | 0041-31-632 1245 | alban.neziri@insel.ch |
Switzerland | |
Dep. of Anesthesiology and Pain Therapy, Bern University Hospital | Recruiting |
Bern, Switzerland, 3010 | |
Contact: Curatolo 0041-31-632 0133 michele.curatolo@insel.ch | |
Principal Investigator: Neziri |
Study Director: | Michele Curatolo | Dep. of Anesthesiology and Pain Therapy, Bern University Hospital |
Principal Investigator: | Neziri | Dep. of Anesthesiology and Pain Therapy, Bern University Hospital |
Responsible Party: | Inslspital, Bern University Hospital, Bern, Switzerland ( Michele Curatolo / Principal Investigator ) |
Study ID Numbers: | KEK 103/08 |
Study First Received: | May 1, 2009 |
Last Updated: | May 1, 2009 |
ClinicalTrials.gov Identifier: | NCT00892411 History of Changes |
Health Authority: | Switzerland: Ethikkommission |
Neuroplasticity Prognosis |
Signs and Symptoms Hypersensitivity Neurologic Manifestations |
Low Back Pain Pain Back Pain |
Signs and Symptoms Hypersensitivity Immune System Diseases Nervous System Diseases |
Neurologic Manifestations Low Back Pain Pain Back Pain |