Cervicogenic headache: pathophysiology, diagnostic criteria and treatment.

Cervicogenic headache is a relatively common and still controversial form of headache arising from structures in the neck. Cervicogenic headache is a unilateral fixed headache characterised by pain that starts in the neck and spreads to the ipsilateral oculo-fronto-temporal area. The pathophysiology of cervicogenic headache probably depends on the effects of various local pain-producing or eliciting factors, such as intervertebral dysfunction, cytokines and nitric oxide. A reliable diagnosis of cervicogenic headache can be made based on the criteria established in 1998 by the Cervicogenic Headache International Study Group or the International Headache Society's most recent International Classification of Headache Disorders (2004). Various therapies have been used in the management of cervicogenic headache. These range from lowly invasive, drug-based therapies to highly invasive, surgical-based therapies. Unfortunately, the paucity of experimental models for cervicogenic headache and the relative lack of biomolecular markers for the condition mean much is still unclear about cervicogenic headache and the disorder remains inadequately treated.