Tests for back pain
Description
Most people with new back pain completely recover within 6 weeks. Because of this, x-rays and other tests are rarely needed in the first 4 to 8 weeks after back pain starts.
In the early stages, having tests to diagnose the cause of your pain will rarely change the treatment your health care provider will suggest. These tests also will not help your back pain go away sooner.
Sometimes you or your provider might suspect a more serious problem is causing your back pain. If this is true, imaging or other tests may be done right away.
Even when pain last longer than 8 weeks, tests are often delayed unless a possible serious problem is suspected. If your provider advises you to have steroid injections or another treatment, tests will be performed to see whether you can benefit from these injections.
Imaging tests
Spine x-ray may be done in your doctor's office. Many people with acute low back pain believe that x-rays of their spine will show the cause of their pain. But this is not true. Also, it is not possible to diagnose a slipped or herniated disk by a spine x-ray alone.
MRI and CT scans are imaging tests that create detailed pictures of the spine.
Bone scan (also called bone scintigraphy) involves injecting a small amount of radioactive material into a vein. This material circulates through the body and is absorbed by the bones. It may help detect subtle spinal fractures, cancer that has spread to the bone, or certain kinds of arthritis.
Myelogram is an x-ray of the spine that requires injecting a special dye into the area around the spinal cord and spinal nerves. It is a helpful test only for some people who had previous surgery or hardware around the spine. CT and MRI scans are usually done now instead of myelograms.
Bone density scan use low dose x-rays of your spine to diagnose low bone density, or osteoporosis. Low bone density may lead to a compression fracture, where the body of the vertebral bone tissue collapses. If you are at risk for osteoporosis, the results of the bone density scan will allow your physician to manage your condition.
Electromyography (EMG) and nerve conduction velocity test
Electromyography (EMG) is a test that checks the health of the muscles and the nerves that control the muscles.
- EMG is most often used when people have weakness and impaired muscle strength.
- It can help tell the difference between muscle weakness that is caused by injury of a nerve that is attached to a muscle and weakness that is caused by a nerve disorder.
Nerve conduction velocity test is a test that may also be done to diagnose nerve damage or destruction.
Nerve injuries that these tests could show may not appear for 2 to 4 weeks after the injury or start of symptoms. These tests are not used often to assess and manage treatment in people with acute low back pain.
Diskography
In many people who have MRIs, results show disk degeneration. In this condition, the disks, which act as cushions between the spinal bones, become drier and start to shrink. Often, it is hard to tell if this finding on an MRI scan is the cause of the back pain.
Diskography is a test that may help determine whether an abnormal disk seen on MRI is the origin of someone's pain. It is generally done only in people who have had pain for at least 4 to 6 months and have not gotten pain relief from other treatments, including surgery. The procedure uses a special x-ray and makes it possible to see the spinal bones while a needle is inserted near the spinal disk.
For the procedure:
- You will be asked to lie on your side and lean slightly forward on the table.
- The first needle is inserted through your skin and muscle until it reaches the outer layer of the disk. A second needle is passed through the first one. It is inserted all the way into the center of the disk.
- Contrast liquid, or dye, is injected into the middle of the disk. This liquid shows up on the x-ray.
- The doctor who is doing your exam will ask you how severe the pain is and if it is the same type of pain you have been having.
Doctors who treat back pain do not all agree that diskography is a helpful procedure for making decisions about care, especially surgery. This is a less common procedure now as it can be painful and can cause more problems, however, it can allow your physician to determine which disk is generating the most pain.
Reviewed By: C. Benjamin Ma, MD, Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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