Low Back Pain
Cause
Most low back pain is triggered by some combination of overuse, muscle strain, and injury to the muscles, ligaments, and discs that support the spine. Many experts believe that over time muscle strain can lead to an overall imbalance in the spinal structure. This leads to a constant tension on the muscles, ligaments, bones, and discs, making the back more prone to injury or reinjury.
The causes of pain in the low back, or lumbosacral region, tend to add on to one another. For example, after straining muscles, you are likely to walk or move in different ways to avoid pain or to use muscles that aren't sore. That can cause you to strain other muscles that don't usually move that way.
The most common causes of low back pain are:
- Injury or overuse of muscles, ligaments, facet joints, and the sacroiliac joints.
- Pressure on nerve roots in the spinal canal. Nerve root compression can be caused by:
- A herniated disc, often brought on by repeated vibration or motion (as during machine use or sport activity, or when lifting improperly), or by a sudden heavy strain or increased pressure to the lower back.
- Osteoarthritis (joint degeneration), which typically develops with age. When osteoarthritis affects the small facet joints in the spine, it can lead to back pain. Osteoarthritis in other joints, such as the hips, can cause you to limp or to change the way you walk. This can also lead to back pain.
- Spondylolysis and spondylolisthesis, vertebra defects that can allow a vertebra to slide over another when aggravated by certain activities.
- Spinal stenosis, or narrowing of the spinal canal, which typically develops with age.
- Fractures of the vertebrae caused by significant force, such as from an auto or bicycle accident, a direct blow to the spine, or compressing the spine by falling onto the buttocks or head.
- Spinal deformities, including curvature problems such as severe scoliosis or kyphosis.
- Compression fractures. Compression fractures are more common among postmenopausal women with osteoporosis, or in men or women after long-term corticosteroid use. In a person with osteoporosis, even a small amount of force put on the spine, as from a sneeze, may cause a compression fracture.
Less common spinal conditions that can cause low back pain include:
- Ankylosing spondylitis, which is a form of joint inflammation (arthritis) that most often affects the spine.
- Bacterial infection. Bacteria are usually carried to the spine through the bloodstream from an infection somewhere else in the body or from IV drug use. But bacteria can enter the spine directly during surgery or injection treatments, or as the result of injury. Back pain may be the result of an infection in the bone (osteomyelitis), in the spinal discs, or in the spinal cord.
- Spinal tumors, or growths that develop on the bones and ligaments of the spine, on the spinal cord, or on nerve roots.
- Paget's disease, which causes abnormal bone growth most often affecting the pelvis, spine, skull, chest, and legs.
- Scheuermann's disease, in which one or more of the bones of the spine (vertebrae) develop wedge-shaped deformities. This causes curvature of the spine (rounding of the back, or kyphosis), most commonly in the chest region.
Other medical conditions that can cause pain that may be similar to low back pain include:
- Pelvic inflammatory disease.
- Aortic aneurysm.
- Peptic ulcers.
- Gallbladder disease.
- Pancreatitis.
- Urinary disorders such as kidney stones or urinary tract infections.
- Prostate disease.
Your state of mind also has an effect on your level of pain and whether it becomes long-lasting (chronic). People who are depressed, under stress, unhappy in their work, or seeking money for an injury are more likely to have chronic back pain.
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| Author: | Shannon Erstad, MBA/MPH | Last Updated: February 6, 2008 |
| Medical Review: | William M. Green, MD - Emergency Medicine Robert B. Keller, MD - Orthopedics | |
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