Gamma Knife Consortium

Cluster headache is a relatively rare periodic head-ache and facial pain syndrome that may persist for weeks or even months. Cluster headaches occur in 0.4 % of the male population and < 0.08 % of the female population.20 Approximately 90 % of patients with CH have an episodic disorder, while 10 % have chronic CH. Chronic CH attacks vary, from closely spaced pain with remissions lasting no longer than 30 days, to continuous pain without remission lasting more than a year.5 In con-trast, episodic CHs are characterized by 1–3 attacks of peri orbital pain per day over a 6–12-week period, followed by an average pain-free interval of 6 months to 1 year, or even remissions lasting years.1,20 Cluster headache may be associated with autonomic symptoms including ipsilateral lacrimation, conjunctival injection, nasal congestion, rhi-norrhea, sweating, pallor, and Horner syndrome.20 Approx-Stereotactic radiosurgery for intractable cluster headache: an initial report from the North America