Chronic pain is a debilitating disorder affecting approximately 100 million people, or almost 30% of the adult population of the United States.1 Among patients with chronic pain, about half report its occurrence to be daily and severe. Chronic pain costs about $630 billion annually and is the leading primary complaint by patients to healthcare providers and the chief reason for lost productivity. The annual cost of pain is greater than that of coronary heart disease ($309 billion), cancer ($243 billion), and diabetes ($188 billion).