Sponsor closed enrollment early based on interim data from the PRISM US Pivotal Study.

The purpose of this study is to evaluate the safety and effectiveness of an implantable device to treat migraine. There are a significant number of patients who have drug refractory migraine and alternative therapies are needed.

Inclusion Criteria:

• Be diagnosed with multiple migraines per month of moderate to severe intensity;
• Be refractory to medication;
• Be an appropriate candidate for the surgical procedures required fo this study;
• Be willing and able to comply with all study related procedures;
• Be capable of reading and understanding patient information materials and giving written informed consent.

Exclusion Criteria:

• Have onset of headache after age 50;
• Are current substance abusers (including alcohol and illicit drugs);
• Have a significant psychiatric disorder;
• Have previously been treated with occipital nerve stimulation (either temporary trial or permanent implant);
• Have had nerve stimulation for pain relief.
• Have had an injection of botulinum toxin in the head or neck within 6 months prior to enrollment;
• Have previously undergone destructive ganglionectomy affecting C2/C3 occipital and/or trigeminal distribution or have an occipital blockade or radiofrequency procedure currently in effect.
• Have a condition currently requiring or likely to require the use of MRI or diathermy;
• Have an active implantable device;
• Are pregnant or lactating or planning to become pregnant in the next 14 months;
• Have participated in any drug or device trial in the last 4 weeks or plant to participate in any other study during the next 14 months.

Insufficient data collected from limited number of implanted subjects.