[A special type of discogenic low back pain: normal signal intensity of magnetic resonance imaging with abnormal discography].

OBJECTIVE

To report a group of special patients showing a normal signal intensity of MRI with a positive discography and discuss its pathogenesis and clinical significance.

METHODS

From August 2003 to November 2008, 288 patients with chronic low back pain were treated. Of these patients, 12 showed a normal intensity signal of MRI in lumbar intervertebral discs with a positive discography. There were 7 males and 5 females aged 20 - 44 years with an average of 29.6 years. The duration of disease was 8 months to 3 years with an average of 1.8 years. Dallas CT grading method was used for assessing the degree of annular disruption.

RESULTS

Of these 12 patients, 33 lumbar discs underwent discography. Twelve discs in 12 patients showed annular disruption and low back pain reproduction. Among 12 painful discs, 3 showed grade 2 annular disruption and 9 showed grade 3 annular disruption.

CONCLUSION

Patients who are refractory to conservative care and have normal signal intensity in lumbar disc MRI and who are suggested as discogenic origin and might need further treatment such as minimal invasive surgery or lumbar interbody fusion should still be examined by discography.