Introduction: This study is to investigate the different results between one isocenter and two isocenters of Gamma Knife treatment for trigeminal neuralgia.
Methods: Between June 2010 and August 2011, 26 patients were included in this study. The patients were divided into two groups based on the randomized rule. Single isocenter was delivered to patients of Group I and two isocenters to Group II patients. The central dose was limited to 85Gy or 90Gy for each patient of both groups. Follow-up was established through the telephone visit. The effect was classified to complete pain relief,partial pain relief,and no effect.
Results: Twenty-six patients were followed up with an average time of 6.3 months. There were 14 patients in Group I and 12 patients in Group II. The average age of Group I patients was 64.5 years and 65.3 years of Group II. The average carbamazepine dose was 600mg/d of Group I patients and 688.9mg/d of Group II patients before treatment. At last follow-up, the number of complete pain relief, partial pain relief and no effect was 8 , 6, 0 in Group I, and 4, 5, 3 in Group II respectively. The mean time to pain relief was 4.72 weeks of Group I patients and 4.65 weeks of Group II patients. Radiation induced brain injury was observed in two patients of Group I to whom the central dose of 90Gy had been delivered. Facial numbness was reported by one Group I patient and two Group II patients. No pain recurrence was reported.
Conclusions: There is not enough evidence for the benefit with two isocenters based on the initial result of this study. A central radiation dose of 90 Gy might increase the risk of radiation induced brain injury. However, the preliminary result of these 26 patients was limited. More cases and longer follow-up are needed.
Patient Care: The research will help to decrease the side-effects of Gamma Knife treatment for trigeminal neuralgia without losing efficacy by limiting the radiation dose.
Learning Objectives: By the conclusion of this session, increaseing the treatment volume to cover a longer distance of the trigeminal nerve root does not help to improve the initial efficacy of Gamma Knife treatment.