REsponse to Combined SONS and ONS in Chronic Cluster headachE (RESPONSE)

Main Inclusion Criteria: Able and willing to provide informed consent Documented chronic cluster headache for at least 1 year as per ICHD-3 criteria Attack frequency of ≥ 4 attacks per week for ≥ 4 weeks before enrolment Documented failure of verapamil (failure meaning ineffective, provoked unacceptable side-effects or contra-indicated) Stable on preventive treatment for at least two weeks prior to enrolment. Agree to refrain from starting new prophylactic cluster headache medication or other preventive treatments, from 4 weeks before entering the baseline period throughout the duration of the study MRI available (not older than 4 years prior to study enrolment) or willing to undergo an MRI to exclude structural lesions potentially causing headache Able and willing to complete a headache Diary Main Exclusion Criteria: Any other chronic primary or secondary headache disorder, unless they can clearly differentiate them from cluster headache attacks based on the quality and associated symptoms Concomitant neuromodulation, except tVNS Previous failure to any implantable neuromodulation device for neurovascular headache Have an existing Active Implantable Medical Device nearby the implant location (e.g. DBS, cochlear implant, …) Metal implants in the skull (e.g. skull plates, seeds) nearby the implant Have a pacemaker or implantable cardioverter defibrillator (ICD) Suboccipital infiltrations with steroids and/or local anaesthetics or use of oral steroids in the past 3 months Use of botulinum toxin injections in the past 12 weeks Calcitonin gene-related peptide inhibitors started less than 12 weeks prior to enrolment Women of childbearing age who are pregnant, nursing or not using contraception