Trigeminal neuralgia related to multiple sclerosis (TNMS) is characterized by severe pain that very often has features of essential neuralgia. Treatment of this pain is very difficult, especially for patients in poor condition. Patients with TNMS will therefore benefit from any progress in treatment strategy.

     The authors performed gamma knife radiosurgery (GKS) as a noninvasive treatment for TNMS and evaluated the success rate for pain relief.

     Between 1996 and 2007, thirty nine patients (F: M=21:18) were treated for TNMS; conservative treatment failed in all of them. The mean age was 55 (range 38-72 years).

     The median follow up was 36 months (range 12 -144 months). The target was the trigeminal root, and the maximum dose was 70 to 80 Gy. Six patients suffered from bilateral pain; therefore, 45 trigeminal nerves were irradiated. Repeated GKS was performed in 24 patients for recurrent pain and the same dose was used.

     Initially, successful results were achieved in 91% of patients, with complete pain relief in 40 %. Relief was achieved after a median latency of 2 months (range 1 day-6 months). Gamma knife surgery initially failed in 9 % of patients. Pain recurred in 55.5 % of patients after a median latent interval of 12 months (4 - 49 months). The initial success rate after a second GKS was 75% and 16.6 % of patients were pain free. Hypaesthesia was observed in 13% of patients after the first GKS and in 29 % after the second GKS. The median interval to hypaesthesia was 6 months (range 2-33 months) after one treatment and 12 months (range 3-39 months) after a second treatment.

     This is a retrospective study.

     These results suggest that GKS for TNMS is a relatively successful and safe method that can be used in patients even if they are in poor condition.

     In case this method fails, other treatment options including other neurosurgical procedures are not excluded.