Repeat Gamma Knife Radiosurgery for Recurrent Glossopharyngeal Neuralgia: A Systematic Review and Our Initial Experience

Background: Glossopharyngeal neuralgia (GPN) is a rare facial pain syndrome with debilitating symptoms. For medication-resistant GPN, stereotactic radiosurgery (SRS) is an emerging treatment option with a promising role; however, recurrence rates after SRS are fairly high. We present a patient who underwent repeat SRS for recurrent GPN and subsequently maintained over 3 years of complete pain relief. For the first time, we present a systematic review of repeat SRS for recurrent GPN. Summary: Twelve cases of repeat SRS for GPN have previously been reported in the literature (13 studies including ours). Among patients with follow-up, initial pain relief was achieved in 83% (n = 10) of cases a median of 5 weeks after repeat SRS; 2 patients failed to obtain any pain relief. A favorable pain response (BNI I-IIIb) was achieved in 67 and 58% of cases at 6 and 12 months, respectively. All 13 were targeted to the glossopharyngeal meatus. Three patients (23%) experienced adverse radiation effects. Five patients (50%) experienced recurrence a median of 14 months after repeat SRS. Two patients (17%) required additional surgical intervention. At the final follow-up, 75% (n = 9) of the patients had a favorable pain outcome. Key Messages: Repeat SRS may be a viable alternative to open surgery for the treatment of recurrent GPN, albeit with an increased risk of adverse radiation effects. Though limited by a small cohort of patients, the best predictors of an effective second treatment may be a response to initial SRS for >5 months, a maximum dose >75 Gy, and a target at the glossopharyngeal meatus. Larger prospective studies are needed to better define its role.