Abstract text (incl. figure legends and references)

Objective: Pulsed radiofrequency (PRF) is a neuromodulation technique used in chronic pain conditions which does not cause irreversible nerve damage. We aimed to evaluate the effectiveness and safety of Gasser and sphenopalatine ganglion PRF in patients with chronic and refractory trigeminal neuralgia (TN) and cluster headache (CH), respectively.

Methods: We performed a retrospective study including patients with TN and CH according to the International Classification of Headache Disorders-ICHD-3, attended at the national reference Pain Unit for refractory pain of our tertiary hospital. We evaluated clinical and demographic variables. The primary endpoint was the reduction in the number of attacks. Secondary objectives were 50% response rate, change in Numerical Rating Scale (NRS), Patient Global Impression (PGI) at 3 months, percentage of recurrence and major adverse events.

Results: Among 293 patients who received radiofrequency in our center, 19 had a headache diagnosis of chronic and refractory TN and 6 CH according to the ICDH-3, therefore a total of 25 patients were analyzed. A reduction in the number of attacks was observed in 14/19(73.68%) of patients with NT and in 5/6(83.3%) of patients with CH. A 50% response rate was observed in 11/19(58%) of patients with TN and there were differences between the NRS at baseline and at 3 months, statistically significant in NT(p<0.05). Among patients with CCH, 4/6 (66.6%) showed a 50% response rate. Pain recurrence occurred in 13/14(92,86%) patients with TN and 5/5(100%) patients with CH, half of them more than one year after RFP.

Conclusions: According to our study, PRF of Gasser and sphenopalatine ganglion is an effective and safe choice for patients with NT and CCH, even considering recurrence, especially in fragile patients not candidates for aggressive procedures.