Effect of periradicular methylprednisolone on spontaneous resorption of intervertebral disc herniations.

STUDY

DESIGN

Prospective comparison of periradicular infiltration with steroid versus saline on the spontaneous resorption of herniated nucleus pulposus in a randomized controlled trial.

OBJECTIVES

To evaluate whether periradicular steroid retards the resorption of herniated nucleus pulposus.

SUMMARY OF BACKGROUND DATA: Rim enhancement around herniated nucleus pulposus is associated with spontaneous resorption of disc herniations. As rim enhancement consists of a macrophage infiltrate, periradicular steroid could theoretically interfere with the resorption process. METHODS.: Patients with disc herniation-induced sciatica were randomized to receive either periradicular methylprednisolone (in combination with bupivacaine) or saline. Lumbar magnetic resonance imaging (MRI) was performed at baseline, at 2 months, and at 12 months. Disc herniation volume (mm3), coverage of rim enhancement (%), and rim enhancement thickness (mm) were evaluated by a radiologist blinded to the allocation. Operated patients were excluded from the 1-year imaging. Changes in the parameters from baseline to 2 months, and from 2 to 12 months, were evaluated with the Mann-Whitney U test.

RESULTS

Change in herniation volume from baseline to 2 months was measurable in 34 patients of both groups, and from 2 to 12 months in 26 patients of the steroid group and 24 patients of the saline group. Significant spontaneous resorption of disc herniations occurred in both groups during the 1-year follow-up. In the subgroup analysis, there tended to be even faster resorption in the steroid group from baseline to 2 months for extrusions, and from 2 months to 12 months for contained herniations. No significant differences were observed in the enhancement parameters (coverage and thickness) between the two treatments.

CONCLUSIONS

Periradicular corticosteroid does not have a negative effect on the spontaneous resorption of the herniated nucleus pulposus.