A discogram (also known as discography) is a diagnostic procedure that involves the dual diagnostic techniques of Fluoroscopy, an X-Ray modality, and a contrast dye, to confirm the presence of degenerative disc diseases. Fluoroscopy involves moving X-Ray images that the doctor is able to see on an computer screen, as well as the ability to record static images and short video clips from these live images. This type of diagnostic procedure gives the doctor the unique ability to look at the discs compared to other tests for a few reasons:
- X-Rays without contrast don't provide good details of the intervertebral discs of the spine. The will show normal spacing between the vertebral bones - which indicate health, or reduced spacing between the vertebrae - which suggests degenerative disc disease. But X-Rays don't actually show much detail of the discs themselves. Typically, on an X-Ray, the vertebral bones show up as mostly white, while the space between them (where the discs are) show up as mostly black. When the discogram is done under Fluoroscopy, the disc is injected with a contrast which will provide much clearer views of the disc's physical structure, as well as physiologic characteristics.
- MRI's and CT Scans provide much more detailed views of the soft tissues of the body, but only provide static images, unlike discograms, where doctors can view what is happening in live time. CTs are good at imaging the soft tissues of the body, such as the intervertebral discs, but they still only all doctors the ability to look at still images.
The Procedure: The injection and pressurization by fluid insertion part of the discography procedure will be done on a Fluoroscopy table. The procedure involves the insertion of a needle into the disc suspected of generating pain, followed by the monitoring and recording of the anatomy and physiology of the disc. A D.O. or medical doctor will operate the Fluoroscopy tube and pressurize the disc by filling it with fluid. After the disc has been pressurized with fluid, any pain responses are recorded (the patient is awake throughout the procedure). This same procedure may be done for any other discs suspected of causing back pain or lower back pain. Doctors may inject discs not though to be affecting the patient's condition to assess their pain response and possibly as a control to see if they are malingering or exaggerating their symptoms. The level of the patient's pain response may assess whether they will be good candidates for surgical procedures such as the discectomy, and what to expect in terms of prognosis and possible post-operative complications.
Next a contrast agent is introduced through injection into the affected discs. A D.O. osteopath or medical doctor will also perform the dye injection. After the contrast agent Is delivered into the discs, a CT Scan will be performed. The CT Scan will show whether the contrast dye remains inside the disc or whether some of it has leaked out. Leakage of the dye may help to positively diagnose a spinal disc herniation.
Risks and Complications: Though this is just a diagnostic procedure, it is technically a surgery. risks associated with this test include discitis, which is inflammation and infection of the disc.
When this test is performed on the discs of the lumbar spine, it is also called a Lumbar provocative discography.