Objectives: Report our initial series in patients suffering from refractory trigeminal and other forms of non-oncological pain syndromes treated with radiosurgery to the contralateral medial thalamus to alleviate pain.

Methods: A fully automated rotating gamma ray unit was used to deliver a high dose of radiation (140Gy) using a 4 mm collimator to the middle nucleus of the contralateral thalamus in 12 patients suffering from refractory trigeminal and other orofacial pain that had proven to be un responsive to most forms of therapies.

Results: From November 2016 to August 2019, 12 patients were treated, and 10 were eligible for follow-up evaluation. The visual analogue scale (VAS) was nine (7-10) and standardized to 10, the Barrow Neurological Institute (BNI) Pain Intensity Score was 5 for all patients, all were using some form of opioid treatments. The mean amount of invasive procedures before medial thalamotomy including radiofrequency, surgical sectioning of the nerve was 3 (1-10), the mean peripheric nerve blocks was 2.2 (1-10) and the number of patients that had received radiosurgery to the nerve was 6. The median follow-up was 384 days (range: 60 to 800).; time to response was 50 days (2-153) All patients described a benefit in response. The average VAS at the time of response was 4 (range: 0-7). BNI at time of response was 3 (1-4), and patients categorized their pain as 'good with pain', 90% were able to reduce at least 1 medicine and 90% were able to reduce their emergency room visits by 25%. At last follow up the average VAS was 6 (0-10). BNI was maintained at 3, and patients categorized their pain as 'regular', 80% of the patients when asked if knowing the result if they would submit themselves to the procedure again answered 'yes'. There were no complications to report attributed to this procedure.

Conclusions: Medial thalamotomy with radiosurgery seems like a viable and safe alternative for patients suffering refractory trigeminal pain. Further investigation to understand its potential role in palliative care in chronic pain patients is needed.