Neuromodulation. 2012 Aug 6. doi: 10.1111/j.1525-1403.2012.00490.x.

Long-Term Outcome in Occipital Nerve Stimulation Patients With Medically Intractable Primary Headache Disorders.
Brewer AC, Trentman TL, Ivancic MG, Vargas BB, Rebecca AM, Zimmerman RS, Rosenfeld DM, Dodick DW.
SourceCollege of Medicine, University of Arizona, Phoenix, AZ, USA; Department of Anesthesiology, Mayo Clinic in Arizona, Phoenix, AZ, USA; Department of Neurology, Mayo Clinic in Arizona, Phoenix, AZ, USA; Department of Plastic and Reconstructive Surgery, Mayo Clinic in Arizona, Phoenix, AZ, USA; and Department of Neurosurgery, Mayo Clinic in Arizona, Phoenix, AZ, USA.

Abstract
Introduction:  Occipital nerve stimulation (ONS) may provide relief for refractory headache disorders. However, scant data exist regarding long-term ONS outcomes. Methods:  The methods used were retrospective review of the medical records of all (nonindustry study) patients who were trialed and implanted with occipital nerve stimulator systems at our institution, followed by a phone interview. Up to three attempts were made to contact each patient, and those who were contacted were given the opportunity to participate in a brief phone interview regarding their ONS experience. Data for analysis were gleaned from both the phone interview and the patient's medical records. Results:  Twenty-nine patients underwent a trial of ONS during the 8.5-year study period. Three patients did not go on to permanent implant, 12 could not be contacted, and 14 participated in the phone interview. Based upon the phone interview (if the patient was contacted) or chart review, ONS was deemed successful in five of the 12 migraine, four of the five cluster headache, and five of the eight miscellaneous headache patients, and therapy was documented as long as 102 months. In one of the 26 patients, success of ONS could not be determined. Among patients deemed to have successful outcomes, headache frequency decreased by 18%, severity by 27%, and migraine disability score by 50%. Fifty-eight percent of patients required at least one lead revision.

Discussion:  These results, although limited by their retrospective nature, suggest that ONS can be effective long term despite technical challenges. The number of patients within each headache subtype was insufficient to draw conclusions regarding the differential effect of ONS. Conclusions:  Randomized controlled long-term studies in specific, intractable, primary headache disorders are indicated.

© 2012 International Neuromodulation Society.

PMID:22882274[PubMed]

My husband had a nerve stimulator implanted in 2010 and made it nearly two full years without a headache.  He in now in the middle of a second CH episode which usually lasts 3 months or so.  Starting to lose all hope that this thing actually works...