Radiosurgical treatment of trigeminal neuralgia: experience of the Radiosurgery Center of the N.V. Sklifosovsky Research Institute for Emergency Medicine

Abstract

The study objective is to evaluate early results of radiosurgical treatment (RST) of drug-resistant trigeminal neuralgia (TN) of various etiology.Materials and methods. Between 01.01.2016 and 01.07.2018 at the Radiosurgery Center of the N.V. Sklifosovsky Research Institute for Emergency Medicine, 14 patients with drug-resistant TN underwent RST. Per magnetic resonance imaging, prior to treatment 7 patients had neurovascular conflict, 2 had demyelination of the root of the trigeminal nerve due to multiple sclerosis, and 5 patients showed no pathologies of the brain. Irradiation of the cisternal portion of the trigeminal nerve at the distance of 7.5 mm from the entry into the brainstem with prescribed dose of 90 Gy was performed. Follow-up period was 8–20 months. The difference in fractional anisotropy (FA) at the affected and healthy sides was evaluated in patients with TN prior to RST to divide them into 2 groups: with significant FA decrease and with moderate FA decrease.Results. All patients who underwent RST with PD >80 Gy (85.7 %) noted decreased level of pain or its full disappearance. In 11 (78.5 %) patients, anesthetic effect manifested itself 3–6 weeks after RST, in 1–3 months after RST. Full analgesic effect was achieved in a patient with idiopathic type II TN (PD 84 Gy) 3 months after RST, in a patient with neurovascular conflict and type I TN (PD 86 Gy) 6 weeks after RST, in a patient with multiple sclerosis and type I TN (PD 81 Gy) 3 weeks after RST. In the last-mentioned patient, pain returned 12 months after RST but with lower intensity. In 2 (14.3 %) patients (PD 80 Gy), no positive effect was observed in 6 months of follow up. Hypesthesia of a face area (RST complication) was diagnosed in only 1 (7.2 %) patient 8 months after RST, and it persisted for 6 weeks gradually regressing. There was no statistically significant correlation between FA decrease and RST outcome, but it was observed that outcome was more favorable in patients with moderately decreased FA.Conclusion. RST of drug-resistant forms of TN with PD >80 Gy significantly reduces pain syndrome 3–6 weeks after treatment and is characterized by low risk of complications.