3 The procedure
3.1 It is believed that cluster headaches are caused by a trigeminal‑autonomic reflex mediated through the sphenopalatine ganglion. This procedure aims to relieve pain and reduce the frequency of cluster headache attacks by implanting a device in the pterygopalatine fossa to stimulate the sphenopalatine ganglion with small electrical currents.
3.2 Implantation of the neurostimulator device is performed with the patient under general anaesthesia. A small incision is made in the mucogingival margin adjacent to the maxillary first or second molar on the affected side. Under X‑ray control, the lead of the neurostimulator device is advanced subperiosteally along the posterior maxilla in order to place stimulating electrodes in the pterygopalatine fossa. Through the same incision in the mucogingival margin, the main body of the device is fixed medial to the zygoma by means of a small plate. After implantation, the device is tested to assess electrode functionality and the patient's physiological responses to stimulation.
3.3 When cluster headaches occur, the patient activates the neurostimulator (up to a pre‑determined maximum dose) by placing a handheld control unit on their cheek, over the area where the main body of the device is implanted.