Back pain in the lower back or low back pain is a common concern, affecting a large number of people at some point in their lifetime. Up to 50% will have more than one episode. Low back pain is not a specific disease. Rather, it is a symptom that may occur from a variety of different processes. In up to 85% of people with low back pain, despite a thorough medical examination, no specific cause of the pain can be identified.

• Low back pain is second only to the common cold as a cause of lost days at work. It is also one of the most common reasons to visit a doctor's office or a hospital's emergency department.

• For 90% of people, even those with nerve root irritation, their symptoms will improve within 2 months, no matter what treatment is used—even if no treatment is given.

• Doctors usually refer to back pain as acute if it has been present for less than a month and chronic if it lasts for a longer period of time.