Neurostimulation therapy in intractable headaches

A proportion of chronic headache patients become refractory to medical treatment and severely disabled. In such patients various neurostimulation methods have been proposed, ranging from invasive procedures such as deep-brain stimulation to minimally invasive ones like occipital nerve stimulation. They have been applied in single cases or small series of patients affected with varying headache disorders: cervicogenic headache, hemicrania continua, posttraumatic headache, chronic migraine, and cluster headache. Although favorable results were reported overall, it is premature to consider neurostimulation as a treatment with established utility in refractory headaches. At present, the most detailed clinical studies have been performed in intractable chronic cluster headache (iCCH) patients, who represent about 1% of all chronic cluster headache (CCH) patients. Various lesional interventions have been attempted in these patients, none with lasting benefits. In recent years, non-destructive neurostimulation methods have raised new hope. Hypothalamic deep-brain stimulation (hDBS) acts rapidly and has lasting efficacy, but is not without risk. Occipital nerve stimulation (ONS) was studied in two trials on a total of 17 iCCH patients. Clinical efficacy was found to be very satisfactory by most patients and by the investigators. Although slightly less efficacious than hDBS, ONS has the advantage of being rather harmless and reversible. At this stage, it should be preferred as first-line invasive therapy for iCCH. Recent case reports mention the efficacy of supraorbital (SNS) and vagal (VNS) nerve stimulation. Whether these neurostimulation methods have a place in the management of iCCH patients remains to be determined.