Stereotactic radiosurgery of essential trigeminal neuralgia using Leksell Gamma Knife model C with automatic positioning system: technical nuances and evaluation of outcome in 130 patients with at least 2 years follow-up after treatment.

The objective of the present study was the evaluation of outcome in 130 patients with essential trigeminal neuralgia, who were treated using Leksell Gamma Knife model C with automatic positioning system and followed at least 24 months thereafter. Radiosurgery was guided by fused thin-sliced magnetic resonance (MR) and "bone window" computed tomographic (CT) images. In all cases, retrogasserian part of the trigeminal nerve at the level of trigeminal incisura was selected as a target, and one 4-mm collimator was used for delivery of the maximum irradiation dose of 90 Gy. The coordinates of the isocenter were adjusted for positioning of the nerve in the center of 80% isodose area, and were corrected in each individual case with regard to presence of distortion artifacts on MR images. Initial relief of the typical paroxysmal facial pain was marked in 127 patients (98%) within a median interval of 3 weeks after treatment. However, in 23 patients the pain re-appeared later on. Overall, at the time of the last follow-up 112 patients (86%) were pain-free, including 86 who remained both pain- and medication-free after initial radiosurgery. In 31 cases (24%), treatment was complicated by facial hypesthesia and/or paresthesia. In conclusion, radiosurgery of essential trigeminal neuralgia results in a high rate of initial pain relief, but pain recurrences and associated complications are not uncommon. The outcome may be influenced by various technical nuances; therefore, treatment should be preferably done in specialized clinical centers with sufficient expertise in the management of this disorder.