Stereotactic radiosurgery is becoming a reliable first-line treatment for TN. These numerous studies of many patients using frameless radiosurgery with the CyberKnife System found the method effective, with low rates of sensory complications and 76% achieving lasting pain relief. Frameless radiosurgery is minimally invasive and compares favorably to other TN treatments.
We explored research that demonstrates the effectiveness of the CyberKnife® System in the treatment of trigeminal neuralgia.
CyberKnife Radiosurgery for Trigeminal Neuralgia
- This study represents the largest single-center experience with radiosurgery on the CyberKnife System for the treatment of TN so far reported. The author reported the clinical outcomes of 387 treatments with three years follow-up.
Patients were set up using a thermosplastic mask and were treated using Synchrony® Skull Tracking™ for targeting accuracy.
Of the 343 patients 12.8% required a second treatment during the observed period. . Patients receiving retreatment had a median dose of 45 Gy over a median volume of 22.5 mm³. All 44 patients achieved good pain control (BNI I-III) at last follow-up, indicating durable effectiveness. Retreatments showed a bimodal temporal distribution.
Image-guided Robotic Radiosurgery for Trigeminal Neuralgia
Authors: Pantaleo Romanelli, Alfredo Conti, Livia Bianchi, Achille Bergantin, Anna Martinotti, Giancarlo Beltramo. (2018)3
2, This study reported a single centers experience for image-guided robotic surgery in 138 patients with TN. Optimal dose and length of nerve treated were analyzed in relation to pain response, complications, and recurrence of pain, to help inform best practice.
Conclusions of study
Shorter nerve length (30 mm3), and lower prescription dose (58 Gy) were associated with treatment failure (P= .01, P= .02, P= .03, respectively). Results were found to be consistent with 2 large studies on Gamma Knife surgery.
Targeting a 6-mm segment of the trigeminal nerve with a prescribed dose of 60 Gy appears safe and effective. Persistent pain control was achieved in most patients with acceptable risk of sensory complications, which were typically found after re-irradiation.
Outcomes of CyberKnife Radiosurgery for Trigeminal Neuralgia in Patients with Multiple Sclerosis
Authors: Guillemette A, Roberge D, Ménard C, Bahary JP, Bou Assi E, Nguyen DK, Obaid S, Fournier-Gosselin MP. (2025)4
3. This retrospective cohort study provides robust clinical data on outcomes after stereotactic radiosurgery (SRS) with the CyberKnife System in patients with multiple sclerosis (MS). Pain relief was assessed using the Barrow Neurological Institute (BNI) pain intensity scale (I to V) and evaluated using Kaplan-Meier curves – with and without medication.
The study highlighted patients with neurovascular compression benefited most, which also underscores the importance of precision imaging to tailor treatment decisions. Their long-term relief rates reached 92.7%, 62.6%, 49.5%, and 32.5%. The most common complication, facial hypesthesia, occurred in 15.7% of cases, but in most cases it was temporary and only mild. Other side effects, such as temporary chewing weakness, were rare and usually temporary. Anesthesia dolorosa was not observed.
Conclusion of study
This was the first known study to date to assess the CyberKnife System for the treatment of trigeminal neuralgia in MS patients. The results demonstrate the efficacy of the CyberKnife System and align with previous Gamma Knife studies. Other treatments such as microvascular decompression, have not conclusively shown effectiveness for these patients, therefore radiosurgery should be considered as a good option to provide pain relief. It was found that patients with MS and a neurovascular conflict appear to benefit from this approach the most. This study help influence clinical decision making.
We spoke to Professor Alexander Muacevic, Medical Director of the European CyberKnife Centre in Munich, Germany regarding trigeminal neuralgia and MS, he reported, “Trigeminal neuralgia is one of the most excruciating and disabling neurological conditions, marked by sudden, electric shock-like facial pain. For patients with MS, the risk is dramatically higher – nearly 20 times that of the general population. Treatment with the CyberKnife System takes only about 30 minutes: A powerful avenue in the interdisciplinary care of MS patients with trigeminal neuralgia.” ~ Prof. Dr. MED. Alexander Muacevic
And finally at ASTRO 2025 Dr. Alan Monroe from Colorado Springs Neurological Associates, Colorado Springs, CO, presented research on ‘A Non-Invasive Stereotactic Mimicking Radiosurgery with a Frameless Robotic Radiosurgery: A Comparison of Dose Prescription Methodologies for Treatment of Trigeminal Neuralgia.
4. The research compares two different frameless robotic radiosurgery planning approaches for treating trigeminal neuralgia: a volumetric technique targeting a longer segment of the nerve at a lower dose, and an isocentric method mimicking the spherical dose distribution of Gamma Knife at a higher dose but to a smaller volume. The retrospective study reviewed 142 patients treated between 2010 and 2022. The first cohort (55 patients) received a median dose of 60 Gy over a 6 mm nerve segment, while the second cohort (87 patients) received up to 85 Gy using the isocentric approach.
Initial adequate pain relief was achieved in 88% of patients, with similar rates between both techniques. Favorable pain responses and complete pain relief were also comparable between groups, though numerical rates of long-term pain control were marginally higher in the isocentric cohort. Patients with Type I trigeminal neuralgia responded better overall, particularly when treated with the higher dose isocentric approach. Treatment-related numbness was observed in both groups, occurring slightly more frequently and earlier in the isocentric group. The study concludes that both radiosurgical planning approaches are acceptable options for treating trigeminal neuralgia, with each offering similar pain control outcomes.
Dr. Alan Monroe M.D. stated “Our research demonstrates that both the volumetric and isocentric frameless robotic radiosurgery approaches provide comparable and effective pain control for trigeminal neuralgia. Notably, patients with Type I trigeminal neuralgia may benefit more from the higher-dose isocentric technique, though both methods are viable options for tailored treatment planning.” ~ Alan Monroe, M.D.
Summary
In patients with trigeminal neuralgia, CyberKnife System radiosurgery consistently demonstrated high initial pain relief, including refractory cases and those with MS. Initial pain relief ranged from 85.7% – 92% within 14 days – 6 months. Long-term durability varied: recurrence can occur in patients, though retreatment remained effective. Higher doses and presence of vascular compression were associated with better outcomes. Complications such as facial hypesthesia and numbness are generally mild and temporary, with severe adverse effects like anesthesia dolorosa rarely observed. These findings highlight the importance of individualized treatment planning and precision imaging, helping to maximize patient comfort and long-term quality of life. Overall, the CyberKnife System provided effective, non-invasive pain control for trigeminal neuralgia.
Read more clinical evidence on the CyberKnife System
References
- NIH (2025), ‘Trigeminal Neuralgia.’ https://www.ninds.nih.gov/health-information/disorders/trigeminal-neuralgia
- Romanelli P, Conti A, Redaelli I, et al. (October 28, 2019) CyberKnife Radiosurgery for Trigeminal Neuralgia. Cureus 11(10): e6014. DOI 10.7759/cureus.6014
- Romanelli P, Conti A, Bianchi L, Bergantin A, Martinotti A, Beltramo G. Image-Guided Robotic Radiosurgery for Trigeminal Neuralgia. Neurosurgery. 2018 Nov 1;83(5):1023-1030. doi: 10.1093/neuros/nyx571. PMID: 29294132; PMCID: PMC6195178.
- Guillemette A, Roberge D, Ménard C, Bahary JP, Bou Assi E, Nguyen DK, Obaid S, Fournier-Gosselin MP. Outcomes of CyberKnife Radiosurgery for Trigeminal Neuralgia in Patients with Multiple Sclerosis. Can J Neurol Sci. 2025 Mar 3:1-7. doi: 10.1017/cjn.2025.37. Epub ahead of print. PMID: 40026079.
- Alan Monroe et al ‘3493 – A Non-Invasive Stereotactic Mimicking Radiosurgery with a Frameless Robotic Radiosurgery: A Comparison of Dose Prescription Methodologies for Treatment of Trigeminal Neuralgia.’ ASTRO 2025