A Patient's Guide to Discograms of the Spine
What it is: A discogram is an X-ray examination of the intervertebral
discs. The test is performed by injecting dye into the center of the injured
disc(s). The dye makes the disc clearly visible on X-ray film and a fluoroscope
What the test shows: This test is used to determine which disc(s) are
damaged and if those discs are causing pain. This test will show if a disc has
begun to rupture and will show if the disc has tears in the tough outer ring
called the "annulus". By injecting fluid to increase the pressure in the disc,
the doctor can tell if the disc is painful. This is sometimes helpful in determining
exactly which disc is causing the pain.
What the test does not show: The discogram is not a test that is done
frequently. Usually the test is done after an MRI if the MRI fails to show a
herniated disc. The discogram is normally done when surgery is being seriously
considered, because the pain has not responded to treatment, and there is no
evidence that the disc is actually herniated. The discogram does not really
show the bones or the nerves that well - only the inside of the intervertebral
How the test is done: A discogram is done by inserting a long needle
into the center of the intervertebral disc itself - into the nucleus pulposus.
The needle is inserted from the back. During a discogram, you will first be
given medication to help you relax, and then a local anesthetic in the skin
around the area of the back where the needle will be inserted. The doctor watches
on a fluoroscope as he inserts the needle to make sure it goes into the correct
disc space. The fluoroscope is a special X-ray TV that allows the doctor to
see your spine and the needle as it moves. Once the doctor is sure the needle
is in the disc space, he will inject a small amount of fluid to cause pressure
in the disc space. If this causes pain, it is a good indication that the disc
is abnormal. Dye is then inserted into the disc that will show up on X-rays.
The X-rays are taken, and generally, a CAT scan is done as well, to see the
disc in cross section. The procedure usually lasts about 40 minutes.
What risks the test has: A discogram requires a needle to be inserted
into the disc. This test has more risks associated with it than most other tests.
This is one of the reasons that doctors prefer to use the "non-invasive" tests,
such as the MRI and CAT scan, first. The risks associated with a discogram include
infection of the disc space, as well as an allergic reaction to the dye. Discograms
are done using X-rays. X-rays use radiation, which in large doses can increase
the risks of cancer. The vast majority of patients who get X-rays will never
get enough radiation to worry about cancer. Only patients who must have multiple
X-rays (hundreds) over many years need worry about this risk.
What the test costs: A discogram of the spine usually has two costs
associated with the test. The first cost is the fee for actually doing the test.
This is called the "technical fee". The second cost is the fee of having a specialist,
such as a radiologist or a spine surgeon, read and interpret the test. This
is called the "professional fee". You may get two bills for this test: one from
the hospital or clinic where you had the discogram done, and one from the specialist
who read the test.
Copyright © 2003 DePuy Acromed.
« Back to Patient Guides