Physical examinations for back pain

For about four out of five people walking into their doctors' offices with low back pain, the cause is unknown. That is, four times out of five the cause of low back pain is deemed "nonspecific." The doctor isn't able to identify a cause of back pain based on:

• What the person tells him or her
• A physical examination

In most cases of back pain, if you have no history of prior cancer or systemic disease and no apparent nerve problems, your doctor may not recommend diagnostic tests. Instead he or she may suggest an initial conservative approach to treatment. That's because the reason for your back pain is likely some sort of nonspecific musculoskeletal cause that may respond well to conservative treatment.

To rule out other causes of back pain, or to confirm a possible cause, your doctor may recommend one or more diagnostic tests. They may include:

• X-rays. X-rays can reveal bone problems, tumors or degenerative changes (wear and tear, or aging) in your spine.
• Computerized tomography (CT). Using computers and X-rays, CT scanners produce a series of images that can define disk and bone problems.
• Myelography. This test involves the injection of a special dye into your spinal canal. After the injection, X-rays of your spine can reveal a herniated disk or other lesions.
• Magnetic resonance imaging (MRI). This test combines a strong magnetic force with radio waves. The result is computer-generated images of bones, muscles, cartilage, ligaments, tendons and blood vessels. MRI testing can identify herniated disks or other problems with your back.
• Electrical nerve conduction test (electromyography, or EMG). This diagnostic approach measures the electrical impulses produced by nerves as they connect from your spinal cord, through your spine and on down to your muscles. Studies of your nerve pathways can confirm nerve injury caused by herniated disks or spinal stenosis.
• Bone scan. During a bone scan, a radiologist injects a radioactive substance (tracer) into one of your veins. Doctors then use a special scanner to locate bone tumors or compression fractures caused by osteoporosis