The use of intradiscal steroid therapy for lumbar spinal discogenic pain: a randomized controlled trial.

STUDY DESIGN

A prospective randomized study of the therapeutic effect of intradiscal steroid injection compared to a saline placebo.

OBJECTIVES

To determine whether intradiscal steroid injection influences the clinical outcome at 1 year in patients with chronic low back pain of discogenic origin.

SUMMARY OF BACKGROUND DATA

Steroids have been used empirically in the treatment of back pain. They have been used in the epidural space and around nerve roots and have been used as an alternative to chymopapain within the disc. Previous studies have, however, shown variable results.

METHODS

A total of 120 patients with chronic low back pain of discogenic origin were enrolled in the study. At discography, if they had concordant pain, they were randomized to injection of normal saline or methylprednisolone into the disc space. These patients were prospectively followed up for 12 months, and they were asked to report pain according to a visual analogue score and their Oswestry Disability Index was recorded. The primary outcome measure was determined as a percentage change in disability, and the results were analyzed using independent samples t test. The secondary outcome measure was a change in the pain score, and this was analyzed using the Mann-Whitney U test.

RESULTS

There was no significant difference in the primary outcome between the two groups (P = 0.71). The steroid group had a mean change of 2.28 (SE 2.49) in percentage disability, while the saline group had a mean change of 3.42 (SE 1.79). With respect to the change in pain score, there was no significant difference between the two groups (P = 0.72). Those patients who had saline injection had a median change in pain score of 0 (interquartile range -1 to 1), whereas those given steroid treatment had a median change in pain score of 0 (interquartile range -0.25 to 1).

CONCLUSIONS

This study demonstrates that intradiscal steroid injections do not improve the clinical outcome in patients with discogenic back pain compared with placebo.