Back Test: Discography
Discography is a type of back test that is still used today, though it is used less often in favor of the MRI. Discography is one type of diagnostic tool that is used to identify the specific level causing the pain. The reason why this test may be valuable is due to the fact that patients often fail to find relief after back surgeries due to the fact that the level of the spine being operated on is not the main pain generator. The pain generator is the structure in or outside of the spine that is the source of the patient's pain symptoms.
If your spine surgeon recommends that you receive this test before a spine surgery, you should ask him or her a few questions. Ask how much useful information this test is expected to provide. You should also ask how likely this test will contribute to a successful surgery.
The discography involves the injection if a needle delivering two types of substances directly into the intervertebral disc thought to be involved with the patient's symptoms: an injection of radiographic dye and an anesthetic substance. These injections will be performed in the presence of a radiographic device capable of providing doctors with real time live X-Ray video or X-ray images. The radiographic device will help the doctors to get a very good look at the physical structure of the disc and its functioning after the dye has been added.
This procedure will begin with the insertion of the needle into the disc, followed by the injection of the dye first. Next, the anesthetic medication will be delivered.
This test may be simultaneously useful as a therapeutic tool to relieve pain and as a diagnostic tool to identify the patient's cause of pain. What diagnostic information might this test provide that an X-Ray or MRI wouldn't? Here are some of the questions doctors may have before the test, and some of the answers that may be found at its conclusion.
What is the condition of the disc being injected? The way that the dye fills the disc may tell doctors a lot about the disc's health. The amount of dye required to fill the space, the appearance of the dye in the disc, and the reproduction of your back pain are important pieces of information generated by the test. All aspects of the test are performed when the patient is awake and alert. If the patient reports a spike in pain as a result of the dye injection, the next step will be the injection of the anesthetic. Pain relief provided by the delivery of the anesthetic will be a characteristic of a positive test.
This test may be used when other tests have been inconclusive for diagnosing the cause of the patient's pain. X-Rays and MRIs may identify several different types of back problems and spinal conditions, but positive findings of spinal conditions don't necessarily mean that the problem found on the radiographic images or video are the cause of pain. Here is one example. There have been several studies done on patients with no history of back pain. Obviously, these patient should have excellent backs based on the fact that their backs feel fine, right? Well, the results actually point out the exact opposite. These patients had nearly the same rate of degenerative disc disease and herniated discs as patients with back pain. So with these studies we see have direct proof that herniated discs don't always lead to back pain. In reality, it is thought that many patients fail to get better following back surgeries as a result of the fact that the herniated disc being treated was not the cause of pain.
What do doctors do when the discography procedure results in a positive test? In many cases, the spine surgeons recommend moving forward with a bony fusion at the level of the disc causing the pain.
There are a couple of reasons why this test is performed less often than it used to be. The success rate for surgeries performed based on a positive discography is relatively low - 27%. Also, there is some evidence that the discography may cause injury to the disc itself, hastening the degeneration of the targeted discs.
The procedure is done using a fluoroscope to enable the surgeon to carefully guide the needle into the interior of the disc. Several discs may be studied during the same procedure.