Overview

• PRF performed on the sphenopalatine ganglion level under ultrasound guidance.
• Standard voltage PRF parameters: 45 V, 5 Hz frequency, 5 ms pulse width, 360 seconds duration, electrode temperature ≤42°C.
• Supravoltage PRF parameters: Higher voltage than standard (e.g., 60-70 V), with same frequency, pulse width, and duration, maintaining temperature ≤42°C to avoid nerve damage.

Eligibility

Inclusion Criteria:

• Diagnosis of chronic migraine according to International Classification of Headache Disorders criteria (≥15 headache days/month for \>3 months, including ≥8 migraine days/month) documented by Completion of 4-week prospective baseline headache diary immediately preceding randomization
  • Failure of ≥2 classes of preventive pharmacological migraine medications (e.g., beta-blockers, antiepileptics, antidepressants...) to get clinically meaningful response ( defined as ≥50% reduction in monthly migraine days), at standard therapeutic doses (Beta-blockers (e.g., propranolol ≥160 mg/day, metoprolol ≥100 mg/day, Antiepileptics (e.g., topiramate ≥100 mg/day, valproate ≥500 mg/day, Tricyclic antidepressants (e.g., amitriptyline ≥50 mg/day, SNRIs (e.g., venlafaxine ≥150 mg/day ) for at least 8 weeks or ≥12 weeks in case of CGRP ).
  • Stable preventive migraine therapy for at least 4 weeks prior to enrollment.
  • MIDAS score ≥11 indicating moderate to severe disability.
  • Ability and willingness to maintain a daily headache diary throughout the study period.
  • Ability to provide written informed consent. Positive response (≥50% pain reduction within 30-60 minutes) to diagnostic INFRATEMPORAL sphenopalatine ganglion block using 2% lidocaine (2 mL) infrazygomatic approach

Exclusion Criteria:

• Medication Overuse Headache per ICHD-3: Simple analgesics (acetaminophen, NSAIDs, non-opioid analgesics) used on ≥15 days per month for \>3 months, OR Triptans, ergot derivatives, opioids, or combination analgesics used on ≥10 days per month for \>3 months.
• Any secondary headache disorder ( cluster headache, hemiplegic migraine, migraine with brainstem aura (distinct pathophysiology); chronic tension-type headache \>10 days/month.
• Any prior SPG block, PRF, radiofrequency thermocoagulation, chemical neurolysis, or neurostimulation of SPG/trigeminal system within 6 month.
• No prior occipital or supra-orbital nerve radiofrequency, cryotherapy, or chemical neurolysis within 3 months
• Use of botulinum toxin (Botox) within 3 months or CGRP monoclonal antibodies within 3 months prior to enrollment.
• Active psychosis, bipolar disorder (current manic/depressive episode), severe depression with suicidal ideation, dementia, or substance use disorder (DSM-5 criteria) within 12 months; PHQ-9 ≥20 or cognitive impairment affecting reporting reliability.
• Cardiac pacemaker, ICD, neurostimulator, or cochlear implant; or ECT.
• Chronic uncontroled hypertension ; history of stroke, intracranial aneurysm, or high risk for cardiovascular events.
• Pregnancy or lactation, Initiation, discontinuation, or modification of hormonal contraceptive therapy within 3 months prior to enrollment.

Coagulopathy (platelets \<100,000 or INR \>1.5) or ongoing anticoagulation not safely withheld.

-Patient refusal.