Lumbar discography is an injection technique used to evaluate patients with back pain who have not responded to extensive conservative (nonsurgical) care regimens. The most common use of discography is for surgical planning prior to a lumbar fusion.
While different discographers may vary the procedure slightly, the following provides an overview of modern technique for a lumbar discogram diagnosing back pain.
Initial Preparation for the Discogram Procedure
An intravenous line is started just in case intra-procedural medications become necessary. Usually, sedation is avoided so as not to interfere with any reactions or sensations you may experience.
Next, you are placed on a specialized table around which a fluoroscopic (x-ray) unit is positioned. Your back is then marked with an ink pen over the disc spaces that will ultimately be examined. Then your back is thoroughly cleansed and sterile drapes are applied. The fluoroscope will also be sterilely draped and the discographer will be in a sterile surgical gown.
Administration of Local Anesthesia
The goal is to anesthetize a core of tissue that extends from your skin to the disc surface. When these tissues are numbed a guide needle is directed towards the disc and will just touch the outer surface of the annulus (the outer margin of the disc).
Through this guide needle a much smaller disc needle is advanced towards and eventually into the center of the disc. This process should not be painful, but sometimes may be.
The discogram procedure usually takes less than an hour to perform. You’ll have soreness from the needle punctures that lasts several days. You may use acetaminophen, ibuprofen or apply an ice pack for a few minutes to ease the soreness. Some physicians prescribe short term narcotic pain medications for use after the procedure.
Pressurizing the Discs - Diagnostic Procedure
After all of the needles are placed, the discs are "pressurized" one at a time. Pressurization consists of injecting small amounts of a sterile liquid (usually contrast material (x-ray dye)) into the center of the disc.
This is the most important part of the study and you must concentrate on what you are feeling. There are essentially three choices:
- You feel nothing
- You feel pressure
- You feel pain
If you feel pain from the injection, the pain is either:
- Familiar pain, which translates into "ouch, that’s my pain!"
- Unfamiliar pain, which belongs to someone else or translates into "ouch, I’ve never felt that pain before."
After each level is pressurized, pictures are taken with the fluoroscopic unit and the needles are removed. Usually, a post-discogram CT is obtained to document the internal architecture of the disc. And that’s it!
The procedure usually takes less than an hour to perform. You’ll have soreness from the needle punctures that lasts several days. You may use acetaminophen, ibuprofen or apply an ice pack for a few minutes to ease the soreness.
Possible Risks and Complications
As with any other invasive test, there are associated risks and possible complications.
- The most feared complication is a disc space infection, which can be very difficult to treat. Fortunately, by using very strict sterile techniques this is a very uncommon complication.
- There are extremely remote possibilities of nerve root injury
- Spinal headache is also a remote risk
With a skilled and experienced discographer who uses modern discography techniques, all of these risks are very rare.
In summary, a discogram is a preoperative study designed to determine if an intervertebral disc is a pain generator. The initial needle placement need not be painful. If pressurization of a disc causes a familiar pain, then surgical obliteration (fusion) of the pain generator(s) may afford significant back pain relief.