Each patient had a discography. This is a special test to show if pain occurs when the disc is pressurized. If the test was positive the patient either got a steroid injection or a saline (placebo) injection. The two groups were compared at the end of one year. Results were measured by change in disability and change in pain levels.
The authors report no difference between the two groups at the end of one year. Thus, they can't recommend the use of steroid injections in patients with discogenic LBP.
Abhay Khot, MS(Orth), DNB(Orth), FRCS(Orth), et al. The Use of Intradiscal Steroid Therapy for Lumbar Spinal Discogenic Pain. In Spine. April 15, 2004. Vol. 29. No. 8. Pp. 833-837.