Discogenic low back pain (DLBP) is a common cause for chronic axial back pain that is often unrecognized and misdiagnosed. This occurs because of the lack of objective findings, a low index of suspicion and limitations of imaging studies.
DLBP results from a fissure or tear of the outer annulus that surrounds the disc nucleus.
The fissures or tears can result from trauma such as a slip and fall, MVA, or a lifting, twisting or bending event. The injury leads to intense back pain that can radiate into the buttocks, posterior thigh or sometimes into the groin. The pain is typically higher with sitting, driving, standing, bending or lifting and lower in a recumbent position.
There are few findings on exam such as muscle spasms, painful range of motion and pain with palpation. The neurological exam is normal. Imaging studies are often unremarkable. A "high intensity" finding in the annulus can be present on MRI that has a 90% positive predictive value for DLBP but this finding is present in less than 20% of patients with DLBP.
Discography is the only reliable means of diagnosing DLBP. Contrast is injected into the disc in an attempt to recreate the pain and to detect any annular tears. The contrast injections are followed by a CT scan for a more detailed evaluation.
Primary treatment for DLBP is aggressive PT supplemented with pain medications. Discography is considered in those who fail six months of conservative treatment. Depending on the results, interventional treatment options include an IDET procedure or spine surgery.