Background and objectives: Serious adverse events related to particulate steroids have curtailed the use of transforaminal epidural steroid injections for radicular pain. Dexamethasone has been proposed as an alternative. We investigated the efficacy, dose-response profile, and safety of 3 doses of epidural dexamethasone.
Methods: A prospective, randomized, double-blind, dose-ranging design was used. A total of 98 subjects were randomized to transforaminal epidural dexamethasone 4 mg (n = 33), 8 mg (n = 33), or 12 mg (n = 32). The primary outcome measure for this study was reduction in radicular pain according to the visual analog scale from baseline, with 30% reduction or higher considered clinically meaningful. Secondary measures included the Oswestry Low Back Disability Scale, Subject Global Impression of Change, Subject Global Satisfaction Scale, and adverse events. Outcomes were assessed at 1, 4, 8, and 12 weeks after injection. Outcome measures, sample size, and statistical analysis were defined before enrollment.
Results: Mean radicular pain according to the visual analog scale compared with baseline was reduced 41.7%, 33.5%, and 26.6% at 4, 8, and 12 weeks, respectively, after injection. Oswestry disability ratings declined from "moderate" at baseline to "minimal" at 4, 8, and 12 weeks after injection. There was no statistical difference between groups for either measure (all P values < 0.05, Bonferroni-corrected). Parallel effects were observed in "impression of change" and "satisfaction" measures. No serious adverse events were noted.
Conclusions: Transforaminal epidural dexamethasone provides statistically significant and clinically meaningful improvement in radicular pain at 12 weeks after injection, with parallel improvements in disability, impression of change, and satisfaction measures. There was no difference in efficacy for dexamethasone 4 mg compared with 8 or 12 mg. The optimal dose of epidural dexamethasone may be lower than 4 mg, further increasing the long-term safety and tolerability of this treatment. Current data are reassuring with regard to the safety of dexamethasone for transforaminal epidural steroid injection.
Trial registration: ClinicalTrials.gov NCT01303354.