Sphenopalatine Ganglion BlockCluster HeadachePterygopalatine FossaGanglia, ParasympatheticAutonomic Nerve BlockStellate GanglionPalate, HardSphenoid BoneMepivacaineHeadacheVascular HeadachesVasoactive Intestinal PeptideEpistaxisHeadache DisordersReflex Sympathetic DystrophyTension-Type HeadacheNerve BlockHorner SyndromeSphenoid SinusMigraine DisordersSumatriptanTrigeminal Autonomic CephalalgiasNasal CavityHeadache Disorders, PrimaryAnesthetics, LocalTrigeminal Nerve