Assessment of LTP-like Pain Amplification in Chronic Low Back Pain Patients

Overview

The present study is aimed to assess the LTP-like pain amplification in chronic low back pain patients to explore the central and peripheral effect for pain LTP.

Full Title of Study: “Assessment of Long-term Potentiation (LTP)-Like Pain Amplification in Chronic Low Back Pain Patients”

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Cross-Sectional
  • Study Primary Completion Date: December 31, 2018

Detailed Description

This study is a cross-sectional study. Two groups, including low back pain group and healthy subjects group will be arranged in this study. 50 subjects will be recruited in each group, The healthy subjects were matched for sex and age in relation to the low back pain group. Conditioning electrical stimulation (100 Hz, repeated 5 times with 10 s intervals, 500 impulses) using circular pin electrodes will be used in both groups to induce LTP-like pain amplification. The pain intensity changes to pinprick and light touch stimuli will be compared between two groups.

Interventions

  • Other: Chronic low back pain patients
    • People must have experienced low back pain for at least 3 months and have reported a minimal pain level of 30 (pain threshold) on the 0-100 pain numerical rating scale (NRS) in the last 7 days.
  • Other: Subjects without chronic low back pain
    • These participants must not have presented episodes of low back pain for more than 7 days in the last 12 months.

Arms, Groups and Cohorts

  • Chronic low back pain patients
    • People must have experienced low back pain for at least 3 months and have reported a minimal pain level of 30 (pain threshold) on the 0-100 pain numerical rating scale (NRS) in the last 7 days.
  • Subjects without chronic low back pain
    • Participants must not have presented episodes of low back pain for more than 7 days in the last 12 months.

Clinical Trial Outcome Measures

Primary Measures

  • Change of pain intensity to pinprick stimuli
    • Time Frame: The pinprick sensation will be measured three times before and six times after the conditioning electrical stimulation with 10 minutes interval throughout the experiment (90 minutes).
    • Mechanical pinprick-evoked perception was assessed by three weighted pinprick stimulators which were randomly applied in the area adjacent to the conditioned site. The subjects indicated the perceived intensity on the same visual analogue scale(VAS).

Secondary Measures

  • Perception Features of conditioning electrical stimulation (CES)
    • Time Frame: All subjects will rate the pain ratings during the 50 seconds stimulation.
    • The subjects were asked to rate continuously the magnitude of pain induced by the 100 Hz CES using a hand-held visual analogue scale (VAS) device. These VAS ratings were sampled by a computer. The VAS ranges from “0″(no sensation”) to “100″ (most imaginable pain) where “30″ means pain threshold.
  • Change of pain intensity to light-stroking stimuli
    • Time Frame: The light-touch sensation will be measured three times before and six times after the conditioning electrical stimulation with 10 minutes interval throughout the experiment (90 minutes).
    • A cotton swab was used for light stroking stimuli (~100mN) for assessing the tactile perception around the conditioned site.
  • Change of pain intensity to single electrical stimulation (SES)
    • Time Frame: The pain ratings to SES will be measured three times before and six times after the conditioning electrical stimulation with 10 minutes interval throughout the experiment (90 minutes).
    • A single rectangular 1 ms constant-current electrical stimulation was applied as a homotopic electrical test stimulus using the same conditioning electrode placed at the conditioned site.

Participating in This Clinical Trial

1. Chronic low back pain patients

Inclusion Criteria

  • Age 21-80 years old.
  • People must have experienced low back pain for at least 3 months and have reported a minimal pain level of 30 (pain threshold) on the 0-100 pain numerical rating scale (NRS) in the last 7 days.

Exclusion Criteria

  • Age below 21 or over 80 years old.
  • Patients were excluded if they had taken pain medications on the day of the assessment or if they had serious spinal pathologies, such as fractures, tumors or inflammatory diseases, such as ankylosing spondylitis, nerve root compromise confirmed by clinical neurological tests or severe cardiorespiratory diseases. Those who were pregnant, patients with cancer and those with a cardiac pacemaker were also excluded.

2. Healthy volunteers.

Inclusion Criteria

  • Age 21-80 years old.
  • These participants must not have presented episodes of low back pain for more than 7 days in the last 12 months.

Exclusion Criteria

  • Age below 21 or over 80 years old.
  • These participants have presented episodes of low back pain for more than 7 days in the last 12 months.

Gender Eligibility: All

Minimum Age: 20 Years

Maximum Age: 60 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Peking University People’s Hospital
  • Provider of Information About this Clinical Study
    • Principal Investigator: Liu Chenjun, Department of Spine Surgery – Peking University People’s Hospital
  • Overall Official(s)
    • Chenjun Liu, Ph.D., Principal Investigator, Peking University People’s Hospital
  • Overall Contact(s)
    • Weiwei Xia, Ph.D., 008613260001978, 523526767@qq.com

References

Biurrun Manresa JA, Mørch CD, Andersen OK. Long-term facilitation of nociceptive withdrawal reflexes following low-frequency conditioning electrical stimulation: a new model for central sensitization in humans. Eur J Pain. 2010 Sep;14(8):822-31. doi: 10.1016/j.ejpain.2009.12.008. Epub 2010 Jan 27.

Mouraux A, Iannetti GD, Plaghki L. Low intensity intra-epidermal electrical stimulation can activate Aδ-nociceptors selectively. Pain. 2010 Jul;150(1):199-207. doi: 10.1016/j.pain.2010.04.026. Epub 2010 May 26. Erratum in: Pain. 2011 May;152(5):1212.

Mørch CD, Hennings K, Andersen OK. Estimating nerve excitation thresholds to cutaneous electrical stimulation by finite element modeling combined with a stochastic branching nerve fiber model. Med Biol Eng Comput. 2011 Apr;49(4):385-95. doi: 10.1007/s11517-010-0725-8. Epub 2011 Jan 5.

Melzack R. The short-form McGill Pain Questionnaire. Pain. 1987 Aug;30(2):191-7.

Xia W, Mørch CD, Andersen OK. Test-Retest Reliability of 10 Hz Conditioning Electrical Stimulation Inducing Long-Term Potentiation (LTP)-Like Pain Amplification in Humans. PLoS One. 2016 Aug 16;11(8):e0161117. doi: 10.1371/journal.pone.0161117. eCollection 2016.

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