Functional anesthetic discography allows diagnosis of lower back pain cause

May 8 2007

Functional anesthetic discography (FAD), a new diagnostic procedure involving injecting anesthetic directly into a spinal disc, can be used to confirm the presence of injured discs as the source of a patient's lower back pain symptoms, according to a new study by researchers from Winthrop-University Hospital in Mineola, NY.

For the study, the researchers performed FAD in 19 consecutive patients who underwent lumbar discography for suspected disc-caused lower back pain. A total of 29 discs were injected with anesthetic and then studied afterward using MDCT and patient response. The researchers found that 19 out of the 29 discs showed a favorable response to the injection in the form of pain relief of the patient.

"We hoped that by using FAD in our practice we could isolate patients that would likely benefit from disc surgery. FAD is a functional examination; it relies on the patient's induction of pain during active patient movement, which is far different than the typical discogram. When the patient performs the movement or position that causes pain, we then inject anesthetic into the disc in hopes of relieving the pain. If the pain is or is not alleviated, then this either confirms the discogram results or proves a false negative or positive discogram, respectfully," said Jonathan Luchs, MD, lead author of the study.

The authors do caution that even though FAD seemed to work in some cases, it often actually raised more questions as to diagnosis. "Many of our patients,although a small number at this time,did have pain relief after FAD, and some even had complete pain relief. This pain relief reveals that these anesthetized discs were the source of the problem, so we view that as beneficial information for the surgeon and patient, confirming that disc surgery is in order. However, the surprising information was that not all patients had the same amount of pain relief with the anesthetic during functional motion. This led us to believe that not all of our patients suffered from merely disc disease, but their pain may be from various spinal contributors. Therefore although this is a new helpful exam that does in many cases add to the localization of back pain, it is not the final answer to diagnosing back pain," said Dr. Luchs.