Bion for Occipital Nerve Stimulation

Inclusion Criteria: 1. Be diagnosed with chronic migraine or primary chronic daily headache 2. Have headaches characterized by pain 3. Be 18 years of age or older; 4. Be willing and able to follow all study-related procedures during course of study; 5. Have exhibited refractoriness to two acute medication regimens and two prophylactic medications from two separate preventive classes. Exclusion Criteria: 1. Have received a botulinum toxin (botox) injection for treatment of headache within the last 90 days; 2. Have previously undergone destructive ganglionectomy 3. Have had a previous surgery in the intended implant area; 4. Have Arnold-Chiari malformation; 5. Have participated within the last 30 days or plan to participate during this study in another device or drug trial; 6. Be pregnant or planning on becoming pregnant during the study period; 7. Have an implanted electrical device (e.g., pacemaker, spinal cord stimulator) that may interfere with this therapy; 8. Demonstrate significant psychological signs, substance abuse symptoms, or behavioral problems on examination and/or history that, in the investigator's judgment, render them inappropriate for the study; 9. Currently require, or be likely to require, diathermy; 10. Have other medical conditions that the investigator believes would confound the study.