Safety and efficacy of percutaneous pulsed radiofrequency treatment at the C1-C2 level in chronic cluster headache: a retrospective analysis of 21 cases.

We performed a study of the safety and efficacy of percutaneous pulsed radiofrequency (PRF) treatment directed at C1 and C2 levels as performed at our local pain clinic in refractory chronic cluster headache (CCH) patients. We identified 21 CCH patients treated with PRF (240 s, max. 45 V, max. 42 °C) directed at the ganglion and/or nerve root of C1 and C2. Data were collected through retrospective analysis of patients' files and include demographic variables, onset and duration of the headache, mean attack frequency, and prior pharmacological treatment. Safety and reduction of attack frequency in the first 3 months after a first PRF treatment was the primary outcome parameter of this study. All patients had been treated with at least two prophylactic drugs and 19 (90%) had previously been treated with verapamil, lithium, and topiramate. Ten patients (47.6%) reported no meaningful effect, four patients (19%) reported a meaningful reduction of < 50%, and seven patients (33.3%) reported a reduction in headache burden of at least 50% in the 3 months following treatment. Two patients reported occurrence or increase in frequency of contralateral cluster attacks. No other adverse events were reported or detected at follow-up. Upper cervical PRF treatment appears to be a safe procedure that could prove effective in the treatment of patients with refractory CCH and warrants a prospective study.