Clinical Trial: Near-infrared Spectroscopic Measurement in Complex Regional Pain Syndrome

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

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

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.

Detailed Summary:

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 theor
Sponsor: Lawson Health Research Institute

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

Original Primary Outcome: Same as current

Current Secondary Outcome:

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


Original Secondary Outcome: Same as current

Information By: Lawson Health Research Institute

Dates:
Date Received: April 24, 2012
Date Started: August 2011
Date Completion:
Last Updated: July 2, 2013
Last Verified: July 2013