Abstract
Study Design: A retrospective cross sectional cohort study of degeneration of the lumbar spine, using pre- and post-discography MRI scans of 28 patients, as compared to two consecutive MRI scans of an age and sex matched control group of 32 patients.
Objective: To determine whether injection of steroid into a lumbar intervertebral disc causes degeneration, as assessed by magnetic resonance imaging (MRI).
Methods: Twenty-eight patients with chronic discogenic low back pain were selected. Each had been investigated with an MRI, discography (with intradiscal injection of methylprednisolone), and a post-discography MRI scan. A randomly selected control group of thirty-two age and sex matched patients, having been examined on two occasions with MRI, was established. Two interpreters blinded to the patient groups assessed the degree of lumbar disc degeneration on the MRI scans on two separate occasions, using the Pfirrmann grading system.
Results: Kappa values proved interpretation consistency as compared with the published Pfirrmann paper. Variables of age and sex in the two groups showed no true variation in whether the discs improved, stayed the same or degenerated. The difference in the proportions for those with and without the injection gave a test statistic of 11.92 (p-value=0.002), indicating a discrepancy in the degeneration between those discs with and without an injection.
Conclusion: Previous studies on intradiscal steroid injections have shown variable results. Animal studies have shown that steroid administered intradiscally causes degeneration and primary calcification in discs. Two prospective double blind clinical trials using intradiscal steroids identified no significant benefit or improvement in the clinical outcome. This study indicates that intradiscal steroid injections cause MRI visible disc degeneration. In association with the results of the clinical trials, this study questions the indications for the use of intradiscal steroids in the management of discogenic low back pain.
These abstracts were prepared by Mr. Brian J C Freeman FRCS (Tr & Orth). Correspondence should be addressed to him at The Centre for Spinal Studies and Surgery, University Hospital, Queens Medical Centre, Nottingham NG7 2UH.
