Frameless Image-Guided Radiosurgery for Initial Treatment of Typical Trigeminal Neuralgia

Objective To review retrospectively initial experience at a single institution using frameless image-guided radiosurgery (IGRS) for trigeminal neuralgia employing the Novalis linear accelerator (LINAC) with ExacTrac robotic patient positioning device. Methods Over an 18-month period, 44 patients (27 women and 17 men; median age 65 years) were treated with frameless IGRS for typical trigeminal neuralgia (14 cases involved left-sided pain and 30 cases involved right-sided pain), responsive to anticonvulsant medications, with Barrow Neurological Institute Pain Scale (BNI-PS) scores of 4 or 5. All cases were initial radiosurgery treatments with an isocenter dose of 90 Gy delivered via a 4-mm circular collimator forming a spheroid dose envelope. Intrafraction positioning data were collected for all patients. The median follow-up was 15 months. Results Overall intrafraction positioning error was 0.49 mm ± 0.44. After treatment, 40 patients achieved a BNI-PS score of IIIb or better; 19 patients achieved a BNI-PS score of I. The median time to pain relief was 4 weeks. Overall, new hypoesthesia was seen in five patients. No other complications were seen. Conclusions Use of frameless IGRS methods for treatment of trigeminal neuralgia showed results similar to the authors' prior experience with frame-based treatment methods. IGRS using frameless methods is a suitable treatment method for patients with trigeminal neuralgia and may be applicable to other functional indications.