Evaluation of Occipital Nerve Stimulation in Intractable Occipital Neuralgias

Inclusion Criteria: * Patients between 18 and 85 years old * Chronic occipital neuralgias as defined by International Headache Society (IHS) more than 6 months with permanent pain associated or not with paroxysm * Secondary occipital neuralgias (post-traumatic, post-surgery, major arthrosis, compression or lesion of the occipital nerve …) * Chronic neuropathic pain according to the Neuropathic Pain Diagnostic Questionnaire (DN4 ≥ 4) * Maximum pain on VAS ≥ 50/100 * Failure of medical treatment (association of neuropathic medication like antiepileptic and/or antidepressant and/or antalgic treatment like paracetamol, tramadol or morphine) and pain management in a pain Unit including multidisciplinary approach, physiotherapy, block test in C1-C2, radiofrequency rhizolysis, and/or corticosteroid infiltration of C2 according to the criteria defined by Health Authorities for spinal cord stimulation. * Reduction of pain with Transcutaneous Electrical Nerve Stimulation (TENS) in occipital area * Neurological examen has to be completed and must be normal except for the occipital neuralgia territory * A negative pregnancy test for women with childbearing potential * Women of childbearing potential must use appropriate method(s) of contraception during the clinical trial * Patients must be capable of giving informed consent and must have signed informed consent * Affiliation to an appropriate health insurance Exclusion Criteria: * Contraindication to the experimental medical devices * Titanium related allergies * Patients with contraindications to general anesthesia * Complete anaesthesia in the C2/Great occipital nerve territory * Drug or alcohol addiction * Psychiatric disorders (psychiatric evaluation) * Any medical or psychological problems which may interfere with a smooth conduction of the study protocol (e.g. cancer with a limited life expectancy) * Need for intensive nursing care * Difficulty in follow-up * Pregnant or lactating women * Women not using contraception * Adults under a legal protection regime (guardianship, trusteeship, "sauvegarde de justice") * Exclusion period for another study * Simultaneous participation in another clinical trial except if that other trial does not affect the StimO study as approved and documented by the sponsor