A randomized placebo-controlled trial of single-dose IM corticosteroid for radicular low back pain

Study Design. A randomized, double-blind, placebo-controlled trial of patients with radicular low back pain who present to an emergency department (ED) within 1 week of pain onset. Objective. We hypothesized that a single intramuscular 160 mg dose of methylprednisolone acetate would improve pain and functional outcomes 1 month after ED discharge if the corticosteroid were administered early in disease symptomotology. Summary of Background Data. Parenteral corticosteroids are not recommended for acute, radicular low back pain, though their role in this disease process is ill-defined. To date, this medication class has only been studied in a highly selected group of patients requiring hospitalization. Methods. Adults between the ages of 21 and 50 who presented to an ED with low back pain and a positive straight leg raise test were enrolled. The primary outcome was change in pain intensity on an 11 point numerical rating scale 1 month after ED visit. Secondary outcomes 1 month after ED discharge included analgesic use, functional disability, and adverse medication effects. Results. Six hundred thirty-seven patients were approached for participation, 133 were eligible, and 82 were randomized. Baseline characteristics were comparable between the groups. The primary outcome, a comparison of the mean improvement in pain intensity, favored methylprednisolone by 1.3 (P = 0.10). Some secondary outcomes favored methylprednisolone, such as use of analgesic medication within the previous 24 hours (22% vs. 43%, 95% CI for difference of 20%: 0% - 40%) and functional disability (19% vs. 49%, 95% CI for difference of 29%: 9% - 49%). Adverse medication effects 1 week after ED discharge were reported by 32% of methylprednisolone and 24% of placebo patients (95% CI for difference of 9%: - 12% to 30%). Conclusion. This study was a negative study, though there was a suggestion of benefit of methylprednisolone acetate in a population of young adults with acute radicular low back pain. Further work with a larger sample of patients is needed.