Effectiveness of Third Occipital Nerve Pulsed Radiofrequency in Cervicogenic Headache

Inclusion Criteria: * Age 18 years or older * Diagnosis of cervicogenic headache according to the International Classification of Headache Disorders, 3rd edition (ICHD-3) * Availability of cranial and cervical spine imaging * At least 5 headache days per month * Inadequate response to pharmacological and/or physical therapy treatments * Ability to understand and provide written informed consent * Positive response to ultrasound-guided diagnostic third occipital nerve block, defined as at least 50% reduction in pain intensity or patient-reported meaningful improvement Exclusion Criteria: * Secondary headache disorders other than cervicogenic headache according to ICHD-3 * Signs or symptoms of cervical nerve root irritation and/or spinal stenosis * Sensory deficit in the greater occipital nerve dermatome * Cranio-cervical structural defects or anatomical abnormalities at or near the target site * Local or systemic infection * Non-pharmacological headache treatment within the last 3 months (e.g., physical therapy, botulinum toxin A, acupuncture, ozone therapy, cognitive behavioral therapy) * Pregnancy or suspected pregnancy * Known allergy to local anesthetic agents * History of malignancy * Known organic disease of the brain or spinal cord * History of cranial or cervical surgery within the last 12 months * Bleeding or coagulation disorders or use of oral anticoagulant therapy * Comorbid conditions that may cause headache (e.g., uncontrolled hypertension, intracranial lesions) * Conditions that may interfere with treatment adherence or outcome assessment (e.g., psychiatric disorders, dementia) * Request for re-treatment due to development of contralateral pain or other pain conditions during follow-up * Refusal to undergo the intervention or withdrawal of consent at any stage of the study