Gamma Knife surgery for glossopharyngeal neuralgia.

Gamma Knife surgery (GKS) is widely recognized as an effective, minimally invasive treatment for intractable trigeminal neuralgia, but the role of GKS in glossopharyngeal neuralgia (GPN) remains unclear. This study involved 2 patients with medically intractable GPN who were treated using GKS. One patient required 2 treatments because of a recurrence of symptoms (at maximum doses of 60 and 70 Gy), and the other patient had a single intervention (at a maximum dose of 75 Gy). The GKS target was the distal part of the glossopharyngeal nerve. Patients were investigated prospectively, treated, and then assessed periodically with respect to pain relief and neurological function. Complete pain relief was achieved initially after all 3 interventions. The first patient was pain free without medication for 2 months after the first treatment (60 Gy) and for 4 months after the second treatment (70 Gy). The second patient (treated with 75 Gy) was still pain free without medication at the last follow-up (12 months). Neither patient had any neurological complications. The initial response of GPN to low-dose GKS was favorable, but symptoms may recur. No adverse neurological effects were observed in any of the lower cranial nerves. It will be necessary to investigate the optimal radiation dose and target of GKS for achieving long-term pain relief in GPN.