Ultrasound-Guided Greater Occipital Nerve Block Across Headache Phenotypes: Outcomes and Determinants of Response in a Prospective Cohort

Greater occipital nerve blocks (GONBs) are used across headache phenotypes, but short-term effectiveness and predictors of response in mixed real-world cohorts remain uncertain. We conducted a prospective observational study of adults with chronic headache phenotypes receiving a single ultrasound-guided proximal (C2) GONB. Primary outcomes were T0 → T1 (1-month) changes in pain (NRS), headache impact (HIT-6), sleep (PSQI), and monthly attacks (crises) using paired Wilcoxon tests. We defined HIT-6 responders as ≥ 10-point reduction. Predictors of response were evaluated with multivariable logistic regression; continuous reductions were modeled with multivariable linear regression. Twenty-nine patients were included (chronic migraine n = 10; cluster n = 5; occipital neuralgia n = 7; cervicogenic n = 7; 69