Bilateral Greater Occipital Nerve Block for Preventing the OnabotulinumtoxinA Wear-off Phenomenon in the Treatment of Chronic Migraine: A Case Series of 12 Patients

Purpose: OnabotulinumtoxinA is widely used to treat chronic migraines; however, the wear-off phenomenon before the next scheduled dose has emerged as a challenge. This study suggests a new strategy for preventing the wear-off phenomenon using bilateral greater occipital nerve block. Methods: We conducted a retrospective review of patients diagnosed with chronic migraine who were treated with onabotulinumtoxinA and bilateral greater occipital nerve block at St. Vincent Hospital from January 2023 to December 2023. Twelve chronic migraine patients with a history of the wear-off phenomenon received a greater occipital nerve block 8 weeks after the initial onabotulinumtoxinA injection for two sessions. Responses to treatment were evaluated with regular follow-ups and daily headache diaries. Results: All patients who had previously experienced the wear-off phenomenon with conventional onabotulinumtoxinA treatment did not experience the wear-off phenomenon during two sessions with an additional greater occipital nerve block administered 8 weeks after each onabolulinumtoxinA injection. Conclusion: Bilateral greater occipital nerve block administered 8 weeks after the initial onabotulinumtoxinA injection effectively prevents the wear-off phenomenon, enabling sustained therapeutic benefits in chronic migraine patients. Further research is needed to confirm these findings in larger cohorts.