Figure 5 High cervical spinal cord stimulators Figure 5 | High cervical spinal cord stimulators. High cervical spinal cord stimulation is performed by introducing a needle into the upper thoracic epidural space and advancing a wire lead through the needle superiorly until the distal tip reaches — depending on the clinical study — the C1 or C2 level. Typically, a trial implantation, during which the stimulator leads are placed and connected to an external battery, is performed first. The trial implantation is an outpatient procedure that can be performed in under an hour. If the stimulator is tolerated and effective, permanent implantation, during which the wires are tunnelled to a subcutaneous pocket where the battery is implanted, is performed at a later date. Schuster, N. M. & Rapoport, A. M. (2016) New strategies for the treatment and prevention of primary headache disorders Nat. Rev. Neurol. doi:10.1038/nrneurol.2016.143