Discography, also known as a discogram, is a diagnostic test to see if the source of a patient's back pain is the disc itself.
Before treating patients for a back condition, it is important to find out what is causing the patient's back pain. To find the cause of the patient's pain it is critical to find out where the patient's pain originates. The two questions to ask are:
- Does the pain come from the disc itself? We do know that the discs themselves have nerve endings in them. Due to arthritic changes in the discs, patients may feel pain as the outer disc ruptures (herniated disc) or if the material in its core becomes depleted (degenerative disc disease). The nerve endings in the disc may sense these arthritic changes and send pain signals to the brain.
- Does the patient feel pain indirectly due to disc disease? Indirect pain to disc disease may be experienced when the disc bulges or herniates, sending part of it our away from the disc and into the spinal nerves and ligaments. When this happens, the source of the pain is not from the disc itself but in the spinal nerves which are impacted as the disc is torn and shed of some of its contents.
A diagnostic physician may describe a spinal disc problem in one of two ways: pinched nerve and disc pain. A pinched nerve describes the second medical pattern listed above. Disc pain describes the second medical pattern as listed above.
How does the discography procedure work? What kind of diagnostic information do the results of the procedure produce? Positive findings from a discogram confirm that the source of the pain originates in the disc itself. A positive finding will include a situation where the patient feels an immediate increase in pain as fluid is injected into the disc itself, causing an increase in internal pressure inside the disc.
Here we will describe the discography procedure.
In the first part of the procedure, the patient lies face down on an examination table. Below the surface of the exam table is an X-ray Fluoroscope that is connected to a video screen. This video screen shows live images of the patient's internal structures to help the doctor guide a needle directly into the center of a patient's disc. The doctor will guide the needle into the disc that is thought to be the source of the patient's pain and fill the disc with a dye. This dye helps doctors to see the disc better under X-Ray.
The Dye will give doctors a better look at the disc to tell what kind of structural damage there is there, if any. The discogram will show doctors if tears are developing in the outer ring and if the disc is about to rupture (herniate).
The injection of this dye fluid will increase pressure in the disc. The doctor will inject the fluid to increase the pressure, and ask the patient if the experience an immediate increase in pain symptoms. Whether or not the patient reports an increase in pain may determine which type of spine surgery is done later, if at all.
Procedure: You may be given an oral medication to help you relax. A local anesthetic is applied around the level of the disc being injected to numb that area of the back. A long needle is inserted through the back and directly into the center of the disc (nucleus pulposus). The fluoroscope X-Ray guidance enables doctors to see the needle as it goes through the skin and all the way into the spine. Once the needle is in the nucleus of the disc, a small amount of fluid is injected to increase pressure. The doctor may do this same injection to the discs above and below it to see if other discs are involve in contributing to the patient's symptoms. If the pressure increase causes pain at that level of the spine or down one of your limbs, it confirms the disc as the cause of pain.