Treatment of postherpetic trigeminal neuralgia with the gamma knife

Postherpetic neuralgia is a syndrome characterized by intractable pain. Treatment of this pain has not yet been successful. Patients with postherpetic neuralgia will therefore benefit from any progress in the treatment strategy. The authors performed gamma knife radiosurgery (GKS) as a noninvasive treatment for postherpetic trigeminal neuralgia (TN) and evaluated the success rate for pain relief.

Between 1995 and February 1999, six men and 10 women were treated for postherpetic TN; conservative treatment failed in all of them. The median follow up was 33 months (range 8-34 months). The radiation was focused on the root of the trigeminal nerve in the vicinity of the brainstem (maximal dose 70-80 Gy in one fraction, 4-mm collimator). The patients were divided into five groups according to degree of pain relief after treatment. A successful result (excellent, very good, and good) was reached in seven (44%) patients and radiosurgery failed in nine (56%). Pain relief occurred after a median interval of 1 month (range 10 days-6 months). No radiation-related side effects have been observed in these patients.

These results suggest that GKS for postherpetic TN 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.