Design and Study Population:

The ethical approval of the current study was obtained from the Local Ethics Committee of Tepecik Education and Research Hospital. In this study, 25 patients who were diagnosed as having chronic refractory migraine and were refractory to conventional treatments, such as oral medications, GONB,and botulinum toxin injection were evaluated.All patients received pulsed RFtherapy to the GON from the proximal (C2) level in the pain clinic between September 2020 and September 2021. In the current study, patients who were highly likely to have a chronic systemic disease that might be the cause of headache, such as hypertension, were excluded from the study. Additionally, patients who already had other primary headache conditions were also excluded.

To assess the outcomes of the intervention, the patients were evaluated in terms of Beck'sDepression Inventory (BDI) scores,Migraine Disability Assessment Score (MIDAS), visual analog scale (VAS) scores, and Pittsburgh Sleep Quality Index (PSQI) scores.VASsare measurement instruments that try to measure a characteristic or attitude that is believed to range across a continuum of values and cannot easily be directly measured. They are often used in epidemiologic and clinical research to measure the intensity or frequency of various symptoms such as pain. MIDAS is a brief, self-administered questionnaire designed to quantify headache-related disability over 3 months. The MIDAS score has been shown to have moderately high test-retest reliability in patients with headaches. Psychological symptoms often coexist in patients with migraine. Symptoms of depression may reinforce comorbidity between depression and chronic refractory migraine. Therefore, we used BDI scores .The PSQI was developed by Buysse et al. It provides a quantitative measurement of sleep quality to identify good and poor sleep. We wanted to evaluate sleep quality in our patients because chronic pain negatively affects sleep quality .These scoring concepts were used preintervention, and at the post interventional 1st and 3rd months. Afterward, whether the patients benefited from the intervention was assessed by subtracting the preintervention score from the post interventional 1st-month score, and the pre intervention score from the post interventional 3rd-month score. Demographic data of all patients, the side of the pain, and the monthly attack frequency and duration were noted.

The treatment was performed in the local operating room under sterile conditions, accompanied by ultrasonographic imaging with a linear probe (6-12-Mhz Philips DC7 color Doppler ultrasound machine), in the prone position, at the C2 level, with the head slightly flexed. No sedation is needed for this intervention.We start visualizing from the occipital protrusion,then we slide the probe inferiorly to find the first bifid spinous process of C2. After finding the C2 level, we move the probe laterally (towards the side where we will use the RF) to identify the obliquus capitis inferior muscle and semispinalis capitis muscle of the neck .The GON is found superficial to the obliquus capitis inferior muscle and deeperto the semispinalis capitis muscle at this level. After identifying the GON, a catheter needle (22-gauge 5 cm 5 mm active tip hybrid electrode) is inserted with an in-plane technique from lateral to medial. After visualizing the electrode tip placed close to the right or left GON, a sensory stimulation test is performed using an RF generator . After the patient reports dysesthesia and a tingling sensation at the occipital area with less than 0.2 V, the Pulsed RF treatment is administered at 5 Hz and 5 milliseconds pulsed width for 360 seconds at 45 V under the constraint that the temperature of the electrode tips does not exceed 42°C