Intra-arterial Sphenopalatine Ganglion Block for Patients With Refractory Headache

Inclusion Criteria: * Established diagnosis of one of the three following headache or facial pain disorders as defined by the ICHD-329 \[chronic migraine, cluster headache, trigeminal neuralgia\] and failure to respond to two or more preventive therapies A. Chronic migraine Failure to respond to two or more preventive therapies including Onabotulinumtoxin A, erenumab, fremanezumab, galcanezumab, topiramate, valproic acid, metoprolol, propranolol, timolol, atenolol, nadolol, amitriptyline, nortriptyline, venlafaxine, duloxetine. This will include status migrainosus. B. Cluster headache Failure to respond to Verapamil, AND one other preventive treatment including Prednisone, Dexamethasone, galcanezumab, lithium, valproic acid, topiramate, external vagus nerve stimulation C. Trigeminal neuralgia Failure to respond to two or more preventive therapies, including: Oxcarbazepine or carbamazepine, and One of the following: gabapentin, pregabalin, baclofen, lamotrigine, phenytoin Exclusion Criteria: * Patients with malignant neoplasm of the pterygopalatine fossa * Pregnancy, lactation * Severe allergic reaction to Dexamethasone * Severe allergic reaction to NSAID * Renal failure * Active systemic infection or fever * Known cerebral vascular disease * Drug or alcohol abuse * Opioid dependency (stable doses ok) * Triptans within 48 hours from the procedure