Thoracic discography is a technique used to diagnose chronic spine pain patients who have not responded well to conservative treatments. Thoracic discography is performed much less frequently than either cervical or lumbar discography because the thoracic spine is relatively stable and disc problems are much less likely in the thoracic discs. The purpose of having a thoracic discogram is to see if a damaged disc is causing thoracic pain. It is similar to a lumbar and cervical discogram in that it is used to identify specific discs that are pinching on nerves causing pain in the back or in the area in which peripheral nerve serves.
A thoracic discography, or discogram, is used to create pressure within a sensitive disc to determine if a specific disc is the cause of the patient’s pain.
Usually, general anesthesia is avoided so the patient can communicate the sensations experienced during the test.
The patient is placed on a specialized table which fits within a fluoroscopic (x-ray) unit. The area over the disc spaces that will be examined is marked, the area is disinfected and surrounded with a sterile drape. The fluoroscope will also be draped with a sterile cover and the discographer will also be dressed in a sterile gown.
Administration of Local Anesthesia
Local anesthesia is used to numb the tissue that extends from the skin to the disc’s 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 edge of the disc).
Through this guide needle a much smaller disc needle is placed into the center of the disc. This process should not be painful.
Pressurizing the Discs
After all of the needles are in place, 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.
During the test the patient will experience:
- Feeling pressure
- Feeling Nothing
- Feeling pain
Pain from the injection is either the familiar pain for which the test is preformed, or an unfamiliar pain caused by the test. The patient’s response will ultimately determine if the disc being tested is the root cause of their pain.
After each level is pressurized, pictures are taken with the fluoroscopic unit and the needles are removed. Usually, a post-discogram CT is taken to document the condition of the disc.
The thoracic discography procedure usually takes less than an hour to perform. The patient may experience soreness from the needle punctures that lasts several days.