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Discogram / Discography
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I. Introduction
The discogram is a test in which water-soluble contrast (dye) containing antibiotic solution is directly injected into the central portion of a disc(s) in the spine (usually lumbar). The idea behind the test is that it helps pinpoint, or target, the disc responsible for a patient’s pain. The test has two main components. The first and most important is to assess the response to the patient’s pain when the contrast is injected into the disc. This part is done with fluoroscopy. The second is to determine the shape and condition of the disc, which is done with a CT scan following the fluoroscopic procedure above.
II. Patient Selection
As with other types of back pain, determining the exact cause can be quite challenging. Oftentimes more than one disc is degenerated. In addition, there are other factors which may be contribute to a patient’s back pain, including facet disease, referred pain, as well as psychological factors. This can make the exact site and level responsible for the disc pain more challenging to localize and diagnose.
Imaging studies (X-rays, MRI and CT scans) are helpful in help in identifying and characterizing the extent of disc degeneration. However, the extent of degeneration doesn’t necessarily correlate with the amount of pain. In other words, some patients may show severely degenerated discs on imaging studies, but be relatively asymptomatic. Conversely, some patients experiencing severe pain from disc disease (discogenic pain) may show relatively mild degenerative findings on imaging studies.
III. Discogenic Pain
Back and/or neck pain
Can only stand or sit for short periods of time without pain
Nonradicular (nonradiating) extremity, thoracic or abdominal pain
Facetogenic, neoplastic, inflammatory and traumatic sources of pain have been excluded
IV. General Information
Discograms are generally performed as an outpatient procedure. We require the patient have a driver with them for after the procedure. It is most helpful for patients to stop taking their medication for back pain (if they are taking any) the day of the procedure, as it allows increased diagnostic accuracy. We may use intravenous sedation for this procedure, and hence we may start an intravenous line in the patient prior to the procedure.
The discogram is a diagnostic, not a therapeutic procedure. In other words, the critical question to answer is whether the pain produced by the discogram at a given disc level matches the patient’s typical pain (concordant) or is different from the patient’s pain (discordant). Reproducing the patient’s pain increases the diagnostic accuracy of the examination.Following the discogram procedure, the patient then undergoes a CT scan in order to evaluate the appearance of the disc, and look for signs of degeneration, tears, etc. |
 Example of Normal Disc Anatomy
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V. Procedure
The procedure is explained to the patient, questions are answered and informed consent is obtained.
The patient is placed prone (stomach down) on the fluoroscopic table, and the lower back is sterilely cleansed with povidone-iodine (Betadine) and alcohol.
The exact level is located with the fluoroscope, and the skin overlying this area is anesthetized (numbed) with lidocaine.
A needle is sterilely advanced into the central portion of the disc. Usually at least two disc levels are injected. One needle is in the suspected abnormal disc(s), and the other is in a more normal appearing disc. This allows for a ‘control’, where we can assess the pain response to the ‘normal’ disc, and how it differs from the ‘abnormal disc’.
Once the two (or more) needles are in position, they are slowly injected one at a time without the patient knowing which disc is being injected. The patient is asked what he or she is feeling (pain or pressure, where the pain is located, the intensity and whether or not it’s typical or atypical of the usual pain) during the injection phase.
The material injected is a small amount of contrast (X-ray dye), mixed with a small amount of antibiotic.
The needles are slowly withdrawn.
The patient then undergoes a CT scan of the injected disc levels of the spine.
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Radiology Medical Group, Inc. (619) 849-XRAY (9729)| © COPYRIGHT 2004 All rights reserved.
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