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.