Treatment outcome of repeat gamma knife radiosurgery for primary trigeminal neuralgia

Abstract

Objective To assess the feasibility, indications and therapeutic effect of repeatgamma knife radiosurgery for treatment of primary trigeminai neuralgia. Methods From January 1995to February 2006, 277 patients with primary trigeminal neuralgia underwent stereotactic radiosurgerytargeting the cistemal trigeminal nerve with a maximal central dose of 70-80 Gy. A second gamma kniferadiosurgery with a maximal central dose of 65-80 Gy was performed in 23 patients with refractory and15 with recurrent trigeminal neuralgia after the primary surgery. The 50% isodose line encompassed thetarget area for radiation. The trigeminal root entry zone was included in a single target area in 33 patients,and in 5 patients, two target areas were chosen. Results All patients were followed up for 12 to 108months (mean 55 months) by telephone. The pain relief lasted for 1 to 180 days (mean 120 days) after thesecond gamma knife radiosurgery. The primary stereotactic radiosurgery resulted in a complete or partialpain relief rate of 91.7%(254/277). In the 23 patients with refractory trigeminal neuralgia, the secondradiosurgery achieved a pain relief rate of 73.9% (17/23), significantly lower than the rate of 100%(15/15) in the 15 patients with recurrent trigeminal neuralgia (P=0.045). Facial numbness or paresthesiaoccurred in 30 patients (10.8%) after the primary radiosurgery, and in another 8 patients (21.1%) after thesecond surgery. Conclusion Gamma knife stereotactic radiosurgery is safe and effective and causesfew complications for relieving trigeminal neuralgia. A repeat gamma knife stereotactic radiosurgery isalso effective for management of recurrent or refractory trigeminal neuralgia, especially in recurrentcases. Key words: Trigeminal neuralgia; Stereotactic radiosurgery; Gamma knife