Intra-arterial Sphenopalatine Ganglion Block for Patients With Refractory Headache

The investigators propose an outpatient, minimally invasive method to deliver Dexamethasone and Ketorolac to the SPG via the intra-arterial route. A microcatheter will be advanced via the radial (preferably) or the femoral artery (in case the radial approach is not feasible) using fluoroscopic guidance and standard interventional techniques, into the distal internal maxillary artery. This artery is a branch of the external carotid artery and supplies the territory of the sphenopalatine ganglion. The microcatheter will be advanced to the ostium of the distal small branches that supply the SPG (i.e. small arteries feeding the vasa nervosum). Once the microcatheter is in a good position, 15 mg Dexamethasone Sodium Phosphate and 15 mg of Ketorolac Tromethamine will be infused over 30 minutes. The procedure will be performed with local anesthetic at the arterial puncture site. Conscious sedation will be used for anxious participants. After the procedure, the participant will be observed for 5 hours in ICU setting and then discharged to home. The procedure will be performed unilaterally for participants with cluster headache and trigeminal neuralgia. The procedure could be performed bilaterally for participants with migraine.