Introduction Greater occipital nerve blocks (GONB) are used in the management of primary headaches.

Methods The severity (verbal rating scale), duration (minutes) and frequency (per day) of headaches before and after GONB was compared in 74 cluster headache (CH) patients. Time to effect, duration of effect and complications were additionally assessed.

Results 17 (23.0%) patients had episodic and 57 (77.0%) had chronic CH. The mean age (standard deviation) was 47.2 (11.4) years, with a preponderance of male sex (62.2%) and right GONB (52.7%). A significant reduction in mean frequency (3.8 (1.9) vs 1.5 (2.3), p<0.001), duration (104.9 (91.7) vs 44.7 (64.1), p<0.001) and severity (9.4 (1.4) vs 3.4 (4.3), p<0.001) was seen after GONB. 56 (75.7%) cases responded to GONB (41 (55.4%) complete and 15 (20.3%) partial responders). Mean and median time to response was 1.9 (3.0) and 1 day. Mean and median response duration was 42.4 (75.9) and 21.0 days. 12 (16.2%) failed to respond. 6 (8.1%) deteriorated (mean and median duration of deterioration 14.0 (8.7) and 17.5 days). Reported complications included tenderness at GONB site (23.0%), neck stiffness (14.9%) and dizziness (8.1%).

Conclusions GONB are an effective procedure in three-quarters of CH cases, providing approximately 3 weeks of benefit with minimal complications. GONB can be considered at the onset of a cluster bout and offer a transitional therapy while waiting for preventive headaches to work in both episodic and chronic CH.