J Pain Res. 2018 Feb 16;11:375-381. doi: 10.2147/JPR.S129641. eCollection 2018. Fontaine D1,2, Santucci S1,2, Lanteri-Minet M2,3,4. Abstract Cluster headache (CH) is a primary headache and considered as one of the worst pains known to man. The sphenopalatine ganglion (SPG) plays
