title: Sphenopalatine ganglion neuromodulation in migraine: what is the rationale?
abstract: OBJECTIVE
  The objective of this article is to review the prospect of treating migraine with sphenopalatine ganglion (SPG) neurostimulation.
  
  
  BACKGROUND
  Fuelled by preliminary studies showing a beneficial effect in cluster headache patients, the potential of treating migraine with neurostimulation has gained increasing interest within recent years, as current treatment strategies often fail to provide adequate relief from this debilitating headache. Common migraine symptoms include lacrimation, nasal congestion, and conjunctival injection, all parasympathetic manifestations. In addition, studies have suggested that parasympathetic activity may also contribute to the pain of migraineurs. The SPG is the largest extracranial parasympathetic ganglion of the head, innervating the meninges, lacrimal gland, nasal mucosa, and conjunctiva, all structures involved in migraine with cephalic autonomic symptoms.
  
  
  CONCLUSIONS
  We propose two possible mechanisms of action: 1) interrupting the post-ganglionic parasympathetic outflow to inhibit the pain and cephalic autonomic symptoms, and 2) modulating the sensory processing in the trigeminal nucleus caudalis. To further explore SPG stimulation in migraineurs as regards therapeutic potential and mode of action, randomized clinical trials are warranted.
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health & Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Khan
authors.forename: Jean
authors.initials: J
authors.lastname: Schoenen
authors.forename: Messoud
authors.initials: M
authors.lastname: Ashina
mesh_terms: D004599:Electric Stimulation Therapy / Q000379:methods*; D006801:Humans; D058542:Implantable Neurostimulators; D008881:Migraine Disorders / Q000628:therapy*; D056739:Pterygopalatine Fossa / Q000503:physiopathology*
keywords: Sphenopalatine ganglion; migraine; neuromodulation; neurostimulation; trigemino-parasympathetic reflex; trigeminovascular pathway