Interventional Neuroradiology
Discogram
A discogram is an x-ray procedure to evaluate the intervertebral disc and to determine if the patient's pain or other symptoms are specifically related to an abnormality of the disc. The intervertebral disc is a structure that is located between the spinal vertebrae and acts as a cushion. It is composed of fibrocartilage (annulus fibrosis) surrounding a rubbery center(nucleus pulposus).
A needle is placed into the nucleus pulposus of an intervertebral disc and a small amount of iodinated contrast is injected. The radiologist will localize the site for needle placement using luoroscopic guidance. In addition to the pain control administered by an anesthesiologist, the radiologist will administer local anesthesia at the site of needle placement. Since the needle tip is in a location near the nerve roots, the patient may briefly experience symptoms such as pain or an electric shock sensation down their leg. A small amount of iodinated contrast agent is injected into the disc. At the time of the injection, the patient will be asked if the injection reproduces their pain or other symptoms.
A series of radiographs are obtained after the injection to evaluate the condition of the disc. In most cases multiple disc levels are injected. Pain and discomfort at the time of the injection are common since one of the goals of this test is to determine if the symptoms are coming from irrtation or compression of nerve roots by the disc. This pain generally subsides to the patient's baseline level following the injection. The patient is conscious in light sleep during the procedure and can ask questions at any time.
After the needle is removed, a CT scan is performed to provide further information. occasionally, needle placement must be made from the midline with the needle crossing the sac that contains the nerve roots. In that instance, the patient may experience a headache after the procedure. If this approach is required, the patient will have to be observed in the hospital for several hours after the needle placement.
