Headache disorders are prevalent, and while medical therapy provides relief to many headache sufferers, a significant number find their headaches unresponsive to treatment.

One new therapy showing promise for such individuals is occipital nerve stimulation (ONS). A thorough review of this subject was included in the January issue of Therapeutic Advances in Neurological Disorders.

This treatment has been used with migraine, cluster headache, hemicrania continua, cervicogenic headache, post-traumatic headache, occipital neuralgia and other headache disorders.

ONS, first used in 1999, requires surgery and includes the placement of electrodes in the back of the neck that connect via a thin wire to an implantable battery-driven impulse generator (IPG) elsewhere in the body. The patient then controls the rate and intensity of pulses by using a handheld control.

Several studies have shown ONS to be beneficial. In one study of 25 people with treatment-resistant migraine, 88% reported at least a 50% reduction in headache frequency or severity after the device was implanted, and the average migraine disability assessment score dropped from severe disability to little disability. In a study of eight patients with cluster headache, 15 months after the ONS procedure, two patients reported their pain was gone; three reported a 90% reduction in the frequency of attacks; two had improved about 40%, and one person reported no benefit.

ONS appears to be a safe treatment, according to authors Giorgio Lambru, MD, and Manji S. Matharu, MD, neurologists at the Institute of Neurology and The National Hospital for Neurology and Neurosurgery in London. Typical complications include lead migration, lead site pain, incision site pain, neck stiffness, battery site pain and contact dermatitis.

How ONS works is not fully understood, and the authors note that multiple mechanisms are likely involved and that those mechanisms may differ according to headache and pain syndromes. One widely accepted premise, however, is the gate-control theory, which suggests that the nerves in the spinal cord function as a gate, and prevent signals from other areas of the body from reaching the brain.

More research is needed in the field of ONS. While the treatment shows promise, the authors note, more information is needed regarding which patients would likely benefit most, what are the most effective surgical techniques, and optimal electrical stimulation.

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