About the Discs
Discography is one of the diagnostic tools that doctors use to identify and get to the root of spinal pain. Normal discs in the spine have nerves in the annulus fibrosis, also known as the outer tissue layers. Injury that affects the discs can also tear the annulus. Patients typically will experience pain while the disc is in the process of healing and new nerve endings are forming.
Discs in the vertebrae also contain a nucleus pulposus in the center, which contains a liquid that allows for weight bearing. This nucleus can also leak after injury, and the contents can get into the outer layers or even the nerve roots that are leaving from the lower part of the spinal cord (cauda equina). These leaking chemicals are irritating to nerves and can make them even more sensitive. This causes pain as well, and disc degeneration may also occur as a result of this loss of liquid. As discs lose water, when we age, degeneration to a certain degree is normal. However, when it is severe, patients are likely to experience increasing pain in areas such as the leg, neck, and back as, having lost the liquid cushioning, the spine puts pressure on nerve roots or facet joints.1
What is Discography?
Patients who present with back, neck, or leg pain to their care provider are often directed by their doctor, who then recommends and needs to perform diagnostic tests to find out if the disc is the cause of the problem. The doctor must then, from there, find out by what method the issue might be treated and then recovered from. MRI is one diagnostic tool available, and while it can show abnormalities in the discs, it, unfortunately, cannot demonstrate to the doctor if it is those particular abnormalities that are the cause of the pain. Sometimes disc abnormalities are benign and do not cause pain. Thus it would often go otherwise unnoticed by the patient anyway.
The discography procedure is specifically meant to determine if the abnormalities that appear in MRI are what are causing the pain. In the discography procedure, needles are inserted into the disc itself. This means that discography is considered to be an “invasive procedure”. Discography is generally used in patients who have not had relief from many months of receiving conservative treatments, such as activity modification, physical therapy, and medication. It is generally not used as a first course of action, as patients should usually try to avoid invasive procedures beyond those which are necessary. The results of the procedures can lead to new treatments, or even surgery, for the patients, depending on the results that are found.2
How Does it Work?
Patients are told to prepare for the discography procedure with solid food restrictions the night before. The patient’s medical history (such as the presence of current pregnancy, diabetes, or a record of epilepsy) and known allergies (such as to xylocaine or X-ray dye) are discussed beforehand.
In the discography procedure, patients are first lightly sedated. They are then put on their side during the minor operation so that the doctors can have easier access to the second or third lowest lumbar disc levels. Then, the contrast material is injected into the disc. If that injected material then exits the center of the disc, the disc is considered to be torn and abnormal. Patients are asked to rate the amount of pain they experience. They are also asked if the injection pain is similar to normal pain locations for their usual symptoms. Patients need to be conscious of their own physical condition in order to answer questions accurately to help the doctor decide how to proceed. CT scanning can happen after the injection. Patients may also receive antibiotics.3
There are some issues with undergoing discography. Discography (discogram) is typically used to determine if surgical intervention is what the patient truly needs. However, the spine professional needs to be careful about false positives. Patients who are falsely deemed positive and are sent to undergo unnecessary surgery are more likely to develop complications that need not have arisen in the first place. The procedure should only be done in patients who have experienced long-term pain and have experienced no relief from pursuing interventions that are less invasive. Patients need to let the doctor know about all allergies. And they cannot be on blood thinners or pain medications around the time of the procedure.4
Complications, such as discitis (infection), urticaria (skin vascular reaction), nerve root injury, bleeding, headache, increased pain, and more, can result. Some doctors have found that the benefits of discography come from conflicting data. While others find it helpful to determine the root causes of the pain.5 The number of false positives from discography could lead to unnecessary surgery. Patients need to be properly selected for this procedure, both physically and psychologically.6
1, 2, 3, 5 http://www.spine.org/Documents/discography_2006.pdf