Prognostic factors in vagus nerve stimulation for drug-resistant epilepsy. Results from a systematic review and meta-analysis of the literature. - Martinelli, Renata; Ciaffi, Gabriele; Fuggetta, Filomena; D'Ercole, Manuela; Burattini, Benedetta; Izzo, Alessandro; Montano, Nicola (Neurosurgical Review, 2026)