Introduction Chronic pain is the leading cause of disability worldwide and is associated with the highest economic cost among all psychiatric and neurologic disorders (1). The impact of pain has many negative consequences in previously healthy adults including loss of work productivity, lost wages, fewer work hours, and increased associated cost of care in the elderly. In the U.S., the economic cost of pain to society, which comprises health care costs and lost productivity value, was estimated to be at least 560 billion dollars in 2010 (2)