Predictors of GON Blockade Success in Migraine

The greater occipital nerve block (GONB) will be performed using anatomical landmarks (distal approach). The injection point is located at the medial one-third of the line between the external occipital protuberance and the mastoid process. A 26-gauge insulin needle will be used for the procedure. The block will be administered bilaterally with 0.5% bupivacaine, 1.5 ml per side (total 3 ml). The intervention will be repeated once weekly for a total of four sessions