Gamma knife radiosurgery for idiopathic and secondary trigeminal neuralgia

Object. The aim of this study was to identify pain relief and treatment morbidity following gamma knife radiosurgery (GKS) for idiopathic and secondary trigeminal neuralgia. Methods. Between May 1992 and December 1999, 15 patients with idiopathic trigeminal neuralgia and 38 patients with secondary trigeminal neuralgia were treated with GKS. Pain improvement was achieved in 13 of the patients with idiopathic pain (pain response rate 86.7%). Seven patients were pain free and another six experienced pain reduction. There were no serious complications; however, two patients suffered a mild facial sensory change 8 months and 9 months, respectively, after GKS. The patients with secondary trigeminal neuralgia were divided into two groups (Group I, 32 patients in whom the trigeminal root entry zone [REZ] near the tumor could not be visualized; and Group II, six patients in whom the trigeminal REZ near the tumor or brainstem lesion could be visualized). In Group I, the pain subsided completely in eight patients and was reduced in seven (pain response rate 46.9%). In Group II, the pain subsided completely in one patient at 2.8 months and was reduced in three patients at a mean follow up of 0.8 months (range 0.6-1 month) after GKS. The pain response rate was 66.7%. Conclusions. The authors believe that GKS is an effective treatment modalities for idiopathic and secondary trigeminal neuralgia, particularly in patients with inoperable lesions.