Prognostic Value of Measures of the Central Hypersensitivity in Patients With Acute Low Back Pain

July 16, 2015 updated by: University Hospital Inselspital, Berne

Prognostic Value of Measures of Central Hypersensitivity in Patients With Low Back Pain

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.

Study Overview

Status

Completed

Detailed Description

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. The investigators will use least square logistic regression models to determine the association of central hypersensitivity with prognosis.

Study Type

Observational

Enrollment (Actual)

154

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Bern, Switzerland, 3010
        • Dep. of Anesthesiology and Pain Therapy, Bern University Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

Patients with acute low back pain referred from primary care.

Description

Inclusion Criteria:

  • Acute low back pain < 6 weeks
  • Age 18-80

Exclusion Criteria

  • History of chronic low back pain
  • Radicular pain
  • Pregnancy
  • Breast feeding

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
All study participants
Patients With Acute Low Back Pain

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Presence or absence of chronic low back pain
Time Frame: 6 months after the acute episode
6 months after the acute episode

Secondary Outcome Measures

Outcome Measure
Time Frame
Mechanisms of central hypersensitivity
Time Frame: During the acute episode of low back pain
During the acute episode of low back pain

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Study Director: Michele Curatolo, MD, PhD, Dep. of Anesthesiology and Pain Therapy, Bern University Hospital
  • Principal Investigator: Monika Müller, MD, PhD, Dep. of Anesthesiology and Pain Therapy, Bern University Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

February 1, 2009

Primary Completion (Actual)

December 1, 2014

Study Completion (Actual)

December 1, 2014

Study Registration Dates

First Submitted

May 1, 2009

First Submitted That Met QC Criteria

May 1, 2009

First Posted (Estimate)

May 4, 2009

Study Record Updates

Last Update Posted (Estimate)

July 17, 2015

Last Update Submitted That Met QC Criteria

July 16, 2015

Last Verified

July 1, 2015

More Information

Terms related to this study

Other Study ID Numbers

  • KEK 103/08

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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