Near-infrared Spectroscopic Measurement in Complex Regional Pain Syndrome

July 2, 2013 updated by: Geoff Bellingham, Lawson Health Research Institute

Near-infrared Spectroscopic Measurement of Tissue Oxygen Saturation and the Vascular Occlusion Test in Complex Regional Pain Syndrome

Recent clinical investigations have suggested that the cause of abnormal pain in complex regional pain syndrome could be ischemia and inflammation, due to poor blood flow to deep tissues from microvascular pathology. This study aims to determine if a new technology called near infrared spectroscopy can measure this microvascular dysfunction. The study hypothesizes that significant differences can be measured in the microcirculation of patients with CRPS-I using near infrared spectroscopy and the vascular occlusion test.

Study Overview

Status

Completed

Conditions

Detailed Description

The pathophysiology of CRPS-1 is unknown yet a considerable number of studies suggest that the fundamental cause of abnormal pain is due to microvascular pathology of deep tissues.

Reduced blood flow to deep tissues such as muscle, nerve, and bone can lead to a combination of inflammatory and neuropathic pain processes (Coderre TJ et al. 2010). Evidence to support this model of microcirculatory dysfunction includes observations that skin capillary oxygenation is decreased and skin lactate is increased in affected limbs of patients (total of 11 patients in lactate study) (Birklein F et al. 2000, Manahan AP et al. 2007). It has also been reported that patients with CRPS-I have abnormal vasodilatory responses after sympathetically-mediated vasoconstriction (Dayan L et al. 2008) and decreased concentrations of nitric oxide in the affected limb (Groeneweg JG et al. 2006).

Near-infrared spectroscopy (NIRS) is a non-invasive method of measuring tissue oxygenation using the differential absorption properties of oxygenated and deoxygenated hemoglobin in biological tissue (Creteur J 2008). Near-infrared light is only transmitted through small vessels with diameter less than 1 mm (arterioles, venules and capillaries). Since NIRS is limited to monitoring only small vessels, it can be used to assess oxygen balance in the microcirculation of skeletal muscle (Creteur J 2008).

Premises Premise 1: Complex regional pain syndrome is associated with microcirculatory dysfunction

After an injury to a patient's limb, it is hypothesized that the pressure exerted by that swelling within a relatively confined anatomical space can occlude the capillaries of adjacent tissues and cause a compartment syndrome-like injury. Coderre et al. (2010) have theorized that the resulting microcirculatory dysfunction causes a persistent inflammatory state which is then responsible for pain generation.

In an animal model of ischemia-reperfusion injury used to study CRPS-1, microscopy of muscle and nerve tissue demonstrates microvascular evidence of a slow-flow/no-reflow phenomenon (Coderre TJ et al. 2010). Existence of a slow-flow/no-reflow state causes persistent inflammation in deep tissue. Animals subsequently develop hyperemia and edema, followed by mechano-hyperalgesia, allodynia, and cold-allodynia lasting for at least 1 month (Coderre et al. 2010). This clinical picture is similar to the clinical signs of those patients afflicted with CRPS-1.

Premise 2: Vascular occlusion testing measures microcirculatory dysfunction NIRS measurement of peripheral tissue oxygen saturation (StO2), combined with a reproducible ischemia-reperfusion challenge to induce reactive hyperemia (vascular occlusion testing - VOT), has been described as a valid and reliable method for assessing microcirculatory dysfunction (De Backer et al. 2010). This involves a short period of forearm ischemia by inflating a blood pressure cuff on the upper arm. The blood pressure cuff is then released after approximately 3 minutes and this followed by reperfusion of the forearm. This stimulates the release of endogenous nitric oxide (NO) from the microvascular endothelium (Harel et al 2008). Measurement of this hyperemic response using NIRS has been demonstrated to be a feasible non-invasive method of quantifying microcirculatory function. This technique shares strong correlation with the gold-standard method of strain gauge plethysmography (Harel et al. 2008).

Study Type

Observational

Enrollment (Actual)

20

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

  • Canada
    • Ontario
      • London, Ontario, Canada, N6A 4V2
        • Pain Clinic, St. Joseph's Health Care London Hospitals

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 75 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Patients with CRPS Type 1 will be selected from a tertiary care chronic pain clinic. Healthy volunteers will be selected from a community sample

Description

Inclusion Criteria:

  • Complex regional pain syndrome type 1 (CRPS-I) of one upper extremity.
  • Healthy volunteers.
  • Diagnosis of CRPS-I established for greater than 12 weeks.

Exclusion Criteria:

  • Pregnancy
  • Lack of informed consent
  • History of peripheral vascular disease requiring angioplasty or bypass surgery
  • History of systemic vasculitis
  • Current use of vasoactive medications
  • Diabetes Type I and II
  • Presently smoking

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
CRPS Type 1
Patients with CRPS 1 affecting a single upper limb
Healthy volunteers
Volunteers without the diagnosis of CRPS Type 1

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Baseline tissue oxygen saturation
Time Frame: Day 1
Day 1

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Occlusion slope during vascular occlusion test
Time Frame: Day 1
Day 1
Reperfusion slope during vascular occlusion test
Time Frame: Day 1
Day 1
Delta StO2
Time Frame: Day 1
Defined as the difference between the maximal tissue oxygenation value after reperfusion and the baseline measurement
Day 1
Post-obstructive hyperemic response
Time Frame: Day 1
Day 1
Thenar muscle oxygen consumption
Time Frame: Day 1
Day 1

Collaborators and Investigators

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

Sponsor

Lawson Health Research Institute

Investigators

  • Principal Investigator: Geoff A Bellingham, MD FRCPC, Western University, Canada

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.

General Publications

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

August 1, 2011

Primary Completion (ACTUAL)

July 1, 2013

Study Completion (ACTUAL)

July 1, 2013

Study Registration Dates

First Submitted

April 24, 2012

First Submitted That Met QC Criteria

April 24, 2012

First Posted (ESTIMATE)

April 26, 2012

Study Record Updates

Last Update Posted (ESTIMATE)

July 3, 2013

Last Update Submitted That Met QC Criteria

July 2, 2013

Last Verified

July 1, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • R-11-382
  • 18119 (Other Identifier: City of Hope Comprehensive Cancer Center)

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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