ONBs are commonly used for treating headache disorders. Few small randomized trials have investigated the benefit of adding corticosteroids to anesthetic for ONBs, and these studies did not demonstrate a large effect of steroids on outcomes. However, no study has assessed the benefit of non-particulate steroids (e.g., dexamethasone), which have lower rates of complication than particulate steroids, allow for better blinding, and have been shown to prolong duration of other types of peripheral nerve blocks.

118 adult subjects considered stable on other preventatives presented for bilateral combined greater/lesser ONBs for a variety of headaches (cluster headache excluded). Participants were randomized to receive either 2 mL of bupivacaine 0.5% (5 mg/mL), 0.5 mL of lidocaine 1% (10 mg/mL), and 0.5 mL of dexamethasone (10 mg/mL) or 2 mL of bupivacaine 0.5% (5 mg/mL), 0.5 mL of lidocaine 1% (10 mg/mL), and 0.5 mL of normal saline 0.9% at each injection site. Telephone follow-up was 1, 2, and 4 weeks after procedure. Primary outcome was the number of weekly headache days at each follow-up visit.

60 participants received dexamethasone+anesthetic; 58 received anesthetic alone. Both groups reported reduction in headache days compared to baseline at all three visits, with no significant difference between groups. Week 1: -1.9 w/ dexamethasone vs. -1.8 w/o dexamethasone, p=0.84. Week 2: -2.3 for both groups, p= 0.90. Week 4: -2.5 for both groups, p= 0.99.

This study did not show a significant reduction in weekly headache days when non-particulate steroids were added to ONBs. This is consistent with current recommendations regarding steroid use for ONBs in the treatment of headache (excluding cluster headache).