Radiosurgical treatment of trigeminal neuralgia: A follow-up experience over three years

Abstract

To assess the safety and efficacy of radiosurgical treatment for trigeminal neuralgia (TN), we reviewed a total of 32 patients with refractory TN treated with gamma knife radiosurgery (GKRS) and followed-up for over 3 years. A median maximum dose of 80 Gy was delivered to the involved trigeminal nerve root entry zone. Treatment outcomes were assessed based on patients’ self-reports. A univariate analysis was used to determine the predictors for treatment outcomes. In a median follow-up of 41 months, an improved response to GKRS was observed in 27 patients (84%). Actuarial analysis showed that the 12, 24, 36, and 58month percentages of improved response were 72, 67, 56 and 47% respectively. Pain relief occurred in a median time of 3.5 months, and was maintained for a median of 21 months. Twelve patients (44%) complained with recurrence of the pain after a median of 10 months. Actuarial analysis revealed that the 12, 24, 36 and 58 month recurrence rates were 7, 15, 15 and 11% respectively. Facial numbness, the only complication, was observed in 3 patients (9.4%). Univariate analysis revealed that a higher maximum dose and a shorter distance between the pontine edge and target center were associated with improved response; that a lower maximum dose and prior surgical treatment experience were associated with increased risk of recurrence of pretreatment pain; and that higher maximum dose and two isocenters were associated with the occurrence of complications. In conclusion, GKRS can effectively relieves the pain with low morbidity, but the long-term benefits that patients derive from it are still limited. Patient outcome is mainly determined by radiation dose and site, and prior surgical treatment experience. Key words: Gamma knife, trigeminal neuralgia, radiosurgery, outcomes.