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Near-infrared Spectroscopic Measurement in Complex Regional Pain Syndrome

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01586377
Recruitment Status : Completed
First Posted : April 26, 2012
Last Update Posted : July 3, 2013
Information provided by (Responsible Party):
Geoff Bellingham, Lawson Health Research Institute

Brief Summary:
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.

Condition or disease
Reflex Sympathetic Dystrophy

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).

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Study Type : Observational
Actual Enrollment : 20 participants
Observational Model: Case Control
Time Perspective: Prospective
Official Title: Near-infrared Spectroscopic Measurement of Tissue Oxygen Saturation and the Vascular Occlusion Test in Complex Regional Pain Syndrome
Study Start Date : August 2011
Actual Primary Completion Date : July 2013
Actual Study Completion Date : July 2013

Resource links provided by the National Library of Medicine

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

Primary Outcome Measures :
  1. Baseline tissue oxygen saturation [ Time Frame: Day 1 ]

Secondary Outcome Measures :
  1. Occlusion slope during vascular occlusion test [ Time Frame: Day 1 ]
  2. Reperfusion slope during vascular occlusion test [ Time Frame: Day 1 ]
  3. Delta StO2 [ Time Frame: Day 1 ]
    Defined as the difference between the maximal tissue oxygenation value after reperfusion and the baseline measurement

  4. Post-obstructive hyperemic response [ Time Frame: Day 1 ]
  5. Thenar muscle oxygen consumption [ Time Frame: Day 1 ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
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

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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01586377

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Canada, Ontario
Pain Clinic, St. Joseph's Health Care London Hospitals
London, Ontario, Canada, N6A 4V2
Sponsors and Collaborators
Lawson Health Research Institute
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Principal Investigator: Geoff A Bellingham, MD FRCPC University of Western Ontario, Canada


Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Geoff Bellingham, Principal Investigator, Lawson Health Research Institute Identifier: NCT01586377     History of Changes
Other Study ID Numbers: R-11-382
18119 ( Other Identifier: Research Ethics Board number )
First Posted: April 26, 2012    Key Record Dates
Last Update Posted: July 3, 2013
Last Verified: July 2013

Keywords provided by Geoff Bellingham, Lawson Health Research Institute:
Complex regional pain syndrome
Near Infrared Spectroscopy
Vascular Occlusion Test

Additional relevant MeSH terms:
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Complex Regional Pain Syndromes
Reflex Sympathetic Dystrophy
Autonomic Nervous System Diseases
Nervous System Diseases
Peripheral Nervous System Diseases
Neuromuscular Diseases