ABSTRACT
Low back pain is defined as the subjective perception of pain in the lower back, buttocks, or leg (numb-
ness and pain in the leg is known as sciatica). There is no objective measure of pain; it can only be
measured subjectively through self-report (pain drawings, pain analogs, pain scales, pain words, pain
diaries, etc.)
Low back pain is a very common problem; it affects about two thirds of the adult population.1 Low
back pain is also a very expensive problem. The estimated costs (direct medical and indirect costs) of
low back pain in the United States are in the range of 50 billion dollars per year, and could be as high
as 100 billion dollars per year.2 Low back pain costs are about three times higher than the total cost
of all forms of cancer diseases.3
