Gamma knife radiosurgery for idiopathic trigeminal neuralgia as primary vs. secondary treatment option

Objective: To enable physicians to remain informed of secondary GKR after multiple surgical choices. This study compares gamma knife radiosurgery (GKR) as a first and a second treatment for the management of medically refractory idiopathic trigeminal neuralgia (TN). Methods: Between May 1998 and May 2008, a total of 86 patients with idiopathic TN underwent GKR, with 62 patients receiving the treatment as a first therapy (primary GKR group) and 24 patients receiving the treatment as a second procedure (secondary GKR group). The median follow-up time was 76.4 months (range 12-161 months). The mean prescription marginal dose delivered to the involved trigeminal nerve root entry zone was 82.4 ± 6.25 Gy for the primary GKR group, and 81.0 ± 4.89 Gy for the secondary GKR group. In the secondary group, eleven patients underwent percutaneous radiofrequency rhizotomy (PRFR), seven underwent microvascular decompression (MVD), three underwent percutaneous glycerol rhizotomy and another three underwent GKR as their first treatment. We excluded a typical, multiple sclerosis or secondary trigeminal neuralgia. Results: No significant differences in radiation dose, time to initial response, recurrence or pain relief were observed between the use of GKR as a primary and a secondary procedure for idiopathic TN. The occurrence of new onset after GKR were the same for the two groups, but overall facial sensory changes was higher in the secondary GKR group. Conclusion: For pain control, GKR can be offered both as a primary and as a secondary procedure, but shows higher overall facial sensory changes in secondary GKR group. The results of our study enable physicians to remain informed of secondary GKR after multiple surgical choices. GKR would be an alternative treatment modality after other surgical treatments including GKR, MVD, PRFR and Glycerol.