The efficiency of the prescribed dose of the gamma knife for the treatment of trigeminal neuralgia

Abstract Background This study designed to evaluate the clinical response of the gamma knife (GK) treatment of primary trigeminal neuralgia (TN) with two modalities of radiation doses. We tried to determine the best of these modalities for the treatment. Patients and methods A randomized clinical prospective study conducted in the Gamma Knife Center, Neuroscience Hospital, Baghdad, Iraq. It extended from July 2016 to June 2017. Forty-five patients with essential TN included in this study. All the patients had either IV and V score of Barrow Neurological Institute Pain scale (BNI) before the Gamma Knife (GK) therapy. Twenty Patients treated with a dose of 80 Gy and twenty-five patients exposed to 89 Gy. The clinical response monitored at fixed time intervals. Imaging evaluation of the nerve thickness used with 3 Tesla MRI before and following the GK therapy. Results 32% of the patients treated with 89 Gy reached pain-free status after one year of GK treatment, while no one of the treated patients with the dose 80 Gy reached that scores. A significant increase in nerve thickness was obtained by the radiation dose 89 Gy as compared to the effect of 80 Gy six-month post GK. After twelve months 32% of those patients treated with 80 Gy had a recurrence, while 19.5% recurrence found in patients treated with 89 Gy. Conclusion The clinical outcome for a longer duration is better when applying the dose 89 Gy.