Persistent and recurring pain is a significant problem for a substantial proportion of the world’s population. Worldwide surveys (1–4) conducted in 1998 of over 197,000 adults established that 28% of the sample had experienced pain in the lower back, 16% severe headache, and 15% pain in the neck region in the prior 3 months (5). A third of the adults reported a limitation due to pain that affected their ability to walk, climb steps without resting, or engage in other activities of daily living.