Linac Frameless Radiosurgery for Trigeminal Neuralgia

From 2010 to 2016, a total of 40 patients (18 males, 22 females, median age: 71 years) were treated with Linac frameless SRS for trigeminal neuralgia. Treatment started with molding a personalized thermoplastic mask, followed by elaborate CT and MRI imaging. For treatment planning, target was a single isocenter to the retrogasserian cisternal portion of the fifth cranial nerve. A single fraction dose of 90 Gy was delivered to the isocenter through a conical collimator with a diameter of 4 or 5 mm by seven non-coplanar arcs, limiting critical dose to brainstem and temporal lobe.

The median time of an entire treatment session was 55 minutes. None of the patients who received treatment suffered from acute toxicity. After a median follow-up of 50 months (range: 12–70 months), 25 patients were pain-free without medications, 10 patients were pain-free with more than 50% reduction of medication doses, 5 patients failed. The 6-month follow-up MRI data confirmed the treatment accuracy by highlighting the treatment isocenter as a radiation-induced lesion exactly located at the planned target.

Linac frameless radiosurgery is found to be a safe and effective treatment option for trigeminal neuralgia.