Cervicogenic headache: mechanisms, evaluation, and treatment strategies.

Cervicogenic headache is a chronic, hemicranial pain syndrome in which the sensation of pain originates in the cervical spine or soft tissues of the neck and is referred to the head. The trigeminocervical nucleus is a region of the upper cervical spinal cord where sensory nerve fibers in the descending tract of the trigeminal nerve converge with sensory fibers from the upper cervical roots. This convergence of nociceptive pathways allows for the referral of pain signals from the neck to the trigeminal sensory receptive fields of the face and head as well as activation of the trigeminovascular neuroinflammatory cascade, which is generally believed to be one of the important pathophysiologic mechanisms of migraine. Also relevant to this condition is the convergence of sensorimotor fibers of the spinal accessory nerve (CN XI) and upper cervical nerve roots, which ultimately converge with the descending tract of the trigeminal nerve. These connections may be the basis for the well-recognized patterns of referred pain from the trapezius and sternocleidomastoid muscles to the face and head. Diagnostic criteria have been established for cervicogenic headache, but presenting characteristics of this headache type may be difficult to distinguish from migraine, tension-type headache, or paroxysmal hemicrania. This article reviews the clinical presentation of cervicogenic headache, its proposed diagnostic criteria, pathophysiologic mechanisms, and methods of diagnostic evaluation. Guidelines for developing a successful multidisciplinary pain management program using medication, osteopathic manipulative treatment, other nonpharmacologic modes of treatment, and anesthetic interventions are presented.