It is thought that the autonomic nervous system is likely involved in migraines and other primary headache disorders given commonly associated symptoms such as nausea, lacrimation, emesis, and rhinorrhea. The sphenopalatine ganglion (SPG) is an extracranial parasympathetic ganglion with both sensory and autonomic fibers. It has therefore been hypothesized that blockade of the sphenopalatine ganglion may produce relief from primary headaches by modulating the autonomic fibers involved in headache disorders.1
While in our anecdotal experience with SPG blocks has been overall very positive, thus far there have been only a few small studies that have investigated it’s use in the Emergency Department. The currently available evidence has been mixed.