Eighty to 90 percent of people in the United States will suffer
from back pain at some time during their lives. Back pain is the second most
common reason people visit their family doctors (just after upper respiratory
infections). On any given day, almost two percent of the entire United States
work force is disabled by back pain. In people under 40 years of age, back pain
is the most common reason for the inability to perform daily tasks. It also is
the direct cause of enormous health care expenses from $20 billion to $30
billion annually.
Pain that primarily affects the back should be distinguished
from a spinal condition that results in mostly leg pain, a condition commonly
called sciatica. Typically, sciatica is the result of a "pinched nerve" in the
spinal column. In most cases, the cause of the sciatica is clearly defined; for
example, a disc problem or arthritis. The cause of an episode of back pain, on
the other hand, often is more difficult to pinpoint, and may be related to the
discs, joints, or soft tissue supports (muscles, ligaments and tendons).
What is acute back pain?
Acute back pain refers to a brief episode of pain that comes on
suddenly. Most people recover from acute back pain within two weeks with minimal
treatment. Using over-the-counter pain relievers -- such as acetaminophen or
ibuprofen -- and getting back to normal activities as the pain permits are
simple and effective treatments for most people with acute back pain.
What is chronic, persistent back pain?
Most back pain is relieved within a few days to a couple of
weeks with simple treatment. When back pain persists beyond two to four weeks --
which is chronic, persistent back pain -- further medical evaluation is
required. This evaluation focuses on a careful assessment of the patient's
medical history and a thorough physical examination to identify, if possible, a
precise cause of the pain. In rare cases, cancer or an infection is found. More
commonly, the pain is related to the spinal joints, discs, or supporting muscles of the back.
What causes back pain?
Back strain is the leading cause (85 percent of cases) of back
pain in the United States. Other causes of back pain include:
- Disc herniation (2 percent of cases) -- A herniated disc is a
rupture or tear of the cartilage that surrounds the vertebral discs.
Pressure from the vertebrae above and below the affected disc squeezes the
cushioning substance (nucleus pulposus) out of the disc. The nucleus
pulposus can press against spinal nerve roots. This can cause severe leg
pain and may cause nerve damage if not treated properly.
- Osteoarthritis/spinal stenosis (1 percent to 2 percent of
cases) -- This is characterized by the constriction or narrowing of the
vertebral canal, the space that surrounds the spinal column.
- Ankylosing spondylitis (less than 1 percent of cases) --
Ankylosing spondylitis is a chronic inflammatory disease that first affects
the spine and adjacent structures. As the disease progresses, vertebrae will
fuse together. This disease has a strong hereditary tendency and primarily
affects men under 30 years of age.
- Spondylolisthesis (3 percent of cases) -- Spondylolisthesis is
the partial forward movement (dislocation) of one vertebra over the one
below it. Usually, the fifth lumbar vertebra is dislocated over the first
sacral vertebra.
- Infection (less than 1 percent of cases)
- Cancer (less than 1 percent of cases)
- Fracture (4 percent of cases)
- Trauma -- An injury due to an accident or fall may cause a
fracture or muscle strain.
- Non-spinal causes -- Non-spinal causes of low back pain include
abdominal aortic aneurysms, kidney stones, infection, or perforating stomach
ulcer.