A discogram is a diagnostic test performed to determine whether a patient's back pain is the result of a spinal-disc abnormality, and, if so, to pinpoint the disc causing the problem. A discogram is performed by injecting a special dye into the patient's spinal disc(s), and using fluoroscopy to view the area in greater detail. The injection creates pressure on the disc and, if the disc is damaged, causes pain.
Due to its invasive nature and the pain it causes, a discogram is used only in instances when a patient has persistent back pain that does not respond to treatment, and to identify damaged discs that need to be removed during spinal-fusion surgery.
A discogram is usually performed as an outpatient procedure that lasts from about 45 minutes to 2 hours. During a discogram, the patient lies down sideways on a special table. After the patient is properly positioned, the injection site on the back is sterilized. In some cases, an additional anesthetic injection is administered to minimize pain during the procedure.
With the help of fluoroscopy, a needle is then inserted through the skin and into each disc to be examined. After a contrast dye is injected into each disc, the needle is removed. Each disc is then examined with an X-ray or CT scan to see if the dye has traveled; this is diagnostically significant because the contrast dye remains in the center of a healthy disc, but spreads outward in one that is damaged.
Immediately after the discogram, the patient is observed for about an hour. Although it is normal to have some pain at the injection site for a few hours, the physician should be contacted immediately if the pain becomes severe.
A radiologist reviews and interprets the discogram's results, and sends them to the physician. The physician then discusses the results with the patient, and determines an appropriate treatment plan.
Although a discogram is generally safe, it does carry a risk of complications, which include headache, nausea, allergic reaction to the contrast dye, infection of the area between discs, and injury to blood vessels in and surrounding the spine.