Glossopharyngeal neuralgia treated by Gamma Knife radiosurgery: safety and efficacy through long-term follow-up.

OBJECTIVE Glossopharyngeal neuralgia (GPN) is a rare and disabling condition. Just as for trigeminal neuralgia, Gamma Knife radiosurgery (GKRS) is increasingly proposed as a therapeutic option for GPN. The purpose of this study was to assess long-term safety and efficacy of GKRS for this indication. METHODS From 2007 to 2015, 9 patients (4 male and 5 female) underwent a total of 10 GKRS procedures. All of the patients presented with GPN that was refractory to all medical treatment, and all had a long history of pain. One patient had previously undergone surgical microvascular decompression. In 5 cases, a neurovascular conflict had been identified on MRI. For the GKRS procedure, the glossopharyngeal nerve was localized on MRI and CT under stereotactic conditions. The target was located at the glossopharyngeal meatus of the jugular foramen. The dose administered to the nerve was 80 Gy in 3 procedures and 90 Gy in the others. Follow-up was planned for 3, 6, and 12 months after the procedure and annually thereafter. RESULTS Eight patients experienced an improvement in their pain. The median length of time from GKRS to symptom improvement in this group was 7 weeks (range 2-12 months). At the first follow-up, 6 patients were pain-free (pain intensity scores of I-III, based on an adaptation of the Barrow Neurological Institute scoring system for trigeminal neuralgia), including 4 patients who were also medication-free (I). One patient had partial improvement (IV) and 2 patients had no change. The mean duration of follow-up was 46 months (range 10-90 months). At the last follow-up 6 patients remained pain-free (pain scores of I-III), including 4 patients who were pain free with no medication (I). No side effect was observed. CONCLUSIONS Because of its safety and efficacy, GKRS appears to be a useful tool for treatment of GPN, including first-line treatment.