Cluster headache is an intense and powerful, one-sided headache accompanied by involuntary symptoms such as red eye, droopy eyelids, flow of tears, small pupils and one-sided facial sweating. The headache is believed to be the most intense of all headaches and among many is totally disabling and of great personal and social consequences. For a small group of patients with episodic and most chronic form, drug therapy has little effect. For them, surgery can be a solution.