Midterm clinical outcomes of ultrasound-guided bilateral C2 level greater occipital nerve block in patients with chronic migraine

Background & Objective: The overall estimated prevalence of chronic migraine is 0.77%-5.1%, leading to a social, emotional, and economic burden. Published data have shown the short-term efficacy of greater occipital nerve block in chronic migraine. This study aimed to assess the midterm clinical outcomes of four sessions of ultrasound-guided bilateral greater occipital nerve (GON) block at the C2 level. In addition, it evaluated the factors that may be associated with clinical success. Methods: This was a single-center retrospective analysis. Demographic data, pre-procedural Beck Anxiety and Depression Inventory (BAI/BDI) scores, headache frequency in a month, headache days in a month, mean headache attack duration (hours), mean pain intensity (Visual Analog Scale 0-100 mm), Migraine Disability Assessment (MIDAS) grades, and headache Impact Test-6 (HIT-6) levels at baseline and at 1-, 3-, and 6-month visits were evaluated. A reduction of 30% in headache days in a month was considered to represent clinical success. Results: Headache frequency, headache days, mean headache attack duration, mean pain intensity, MIDAS grades, HIT-6 levels, and medication overuse improved at 1-, 3-, and 6-month visits compared to the baseline (p < .001). There was no statistically significant correlation between clinical success at 6 months and age, disease duration, baseline attack duration, pain severity, MIDAS grades, HIT levels, BDI scores, and BAI scores .279, .193, .160, .826, .068, .207, .389, and .076, respectively). Conclusion: Clinical improvement, reduction in disability and impact of headache, and even transformation to episodic migraine occurred up 6 months after four sessions of GON block at the C2 level in patients with chronic migraine. Also, clinical responsiveness at the 6-month visit was not related to age, migraine characteristics, baseline depression and anxiety, or headache disability scores.