The 2007-2008 Tobias Grant Award for PhDs for CRPS research will engineer solutions for CRPS. At Massachusetts General Hospital, Associate Professor of Neurology Anne Louise Oaklander, MD, PhD, and the new Tobias-funded post-doctoral fellow, Max Klein, PhD, are taking an engineering approach to the diagnosis and treatment of CRPS.

Drs. Klein and Oaklander will investigate laser Doppler flowmetry for its diagnostic potential. This technique illuminates the skin surface with a laser to measure blood flow beneath the skin. Most CRPS patients have abnormal microcirculation in their CRPS-affected area. This microcirculation is controlled by the “small fiber” nerve cells that seem to be damaged in CRPS. Measurements of nerve-mediated blood flow can then be related to skin biopsy nerve cell counts. Dr. Klein will work to evaluate this correlation through an application of advanced laser Doppler flowmetry techniques to patients whose nerve injuries have been well-characterized through biopsies.

“I am excited to be applying my engineering background in a practical way to these issues in CRPS research. So much of what we use in medicine today is actually engineered from related fields,” explained Dr. Klein. “For instance, imaging techniques such as magnetic resonance imaging (MRI) are offshoots of chemical analysis techniques based on the physics of chemical compounds. For CRPS treatment, spinal cord stimulators merge electronic signal processing with materials science to generate and then deliver, through small wires, stimulation to the to the injured nervous system.”

The relief of chronic pain, like that caused by CRPS, has entered the electronic age with the development and application of spinal cord stimulators. While their exact mechanisms of their effectiveness are not well-understood, they are an effective means of pain relief for many chronic pain sufferers. Drs. Klein and Oaklander will try to adapt spinal cord stimulator leads for implantation near the sciatic nerve of the rats in which the CRPS animal model has been developed. The adaptation of electrodes for animal nerves is a substantial engineering challenge, but there is a potentially tremendous additional benefit of directly observing the effects of nerve stimulators on the sciatic nerve and spinal cord, shedding some light on the underlying mechanisms of their effectiveness.

In 2006, Dr. Oaklander’s group identified changes in the density of nerve fibers within skin biopsies from patients suffering from chronic pain. In 2007, they confirmed their observations in rats, by building a rat model of CRPS-I. Skin biopsies, however, are too complicated for routine diagnosis. A noninvasive technique would help to diagnose CRPS earlier, without invasive skin biopsies and the time-consuming processing of tissue samples.

RSDSA Review. Winter 2008.