Effect of gamma knife on secondary trigeminal neuralgia

The following study was conducted to evaluate the results of Gamma Knife stereotactic radiosurgery in the management of secondary trigeminal neuralgia. 53 patients suffering from secondary trigeminal neuralgia were studied and the results reported. We defined four therapeutic groups: group I correspond to essential trigeminal neuralgia. The primary aim was tumor control in group IV and pain cessation in group III and II (visualization of the fifth nerve root was possible in group II but not in group III). The target dose of the radiosurgery used in the current study varied from 20 to 40 Gy in group III and IV and from 70 to 90 Gy in group I and II. At short-term follow-up, 37 patients (74%) were pain-free, 9 patients (18%) were improved (50%-90% relief) and only 4 patients (8%) experienced treatment failure. Among the patients with early treatment success, 10 patients experienced a complete recurrence of pain in the four succeeding years, and 11 initially pain-free patients deteriorated to partial pain relief. The median time to pain relief was three months (range 1 day to 1 year). The mean follow-up was 32 months (range 7 to 60 months). No patient developed increased facial pain or deafferentation pain. Among the 53 patients, only two exhibit a slight facial hypesthesia and one patient described motor fasciculation related to Gamma Knife treatment. In our experience Gamma Knife surgery appears a safe and effective method for the treatment of secondary trigeminal neuralgia.