The purpose of this compassionate use study is to provide clinical and technical support of the Bion® microstimulator system to the subjects who have decided to keep the system for relief of headache symptoms that have not responded to medical treatment. These study subjects were enrolled and implanted with the Bion® system during a previous clinical investigation of the Bion® for occipital nerve stimulation (ONS) in the United States.

Inclusion Criteria:

• Subject participated in a prior clinical feasibility study of the Bion for occipital nerve stimulation in the treatment of chronic headaches (IDE G030225) and remained implanted with the Bion system.
• Subject elects to enroll in this compassionate use study and provides written informed consent.
• Subject understands the type and duration of clinical, technical or product support provided in the study.
• Subject is willing to comply with protocol-required activities.

Exclusion Criteria:

• Subject is currently participating or intends to participate in another investigational drug or device clinical trial for chronic headaches during the study period.

Subjects who were enrolled and implanted with the Bion® system during a prior feasibility clinical investigation of the device for occipital nerve stimulation (ONS) in the United States.