title: Microvascular decompression for glossopharyngeal neuralgia using intraoperative neurophysiological monitoring: Technical case report.
abstract: BACKGROUND
  Glossopharyngeal neuralgia (GN) is a rare functional disorder representing around 1% of cases of trigeminal neuralgia. Lancinating throat and ear pain while swallowing are the typical manifestations, and are initially treated using anticonvulsants such as carbamazepine. Medically refractory GN is treated surgically. Microvascular decompression (MVD) is reportedly effective against GN, superseding rhizotomy and tractotomy.
  
  
  METHODS
  We encountered three patients with medically refractory GN who underwent MVD using intraoperative neurophysiological monitoring (IONM). The offending vessels were the posterior inferior cerebellar arteries, which were confirmed intraoperatively via a transcondylar fossa approach to be affecting the root exit zones of the glossopharyngeal and vagus nerves. As IONM, facial motor-evoked potentials (MEPs) and brainstem auditory-evoked potentials were monitored during microsurgery in all three patients. Pharyngeal and vagal MEPs were added for two patients to avoid postoperative dysphagia.
  
  
  RESULTS
  GN disappeared immediately after surgery with complete preservation of hearing acuity and facial nerve function. Transient mild swallowing disturbance was observed in 1 patient without pharyngeal or vagal MEPs, whereas the remaining two patients with pharyngeal and vagal MEPs demonstrated no postoperative dysphagia.
  
  
  CONCLUSIONS
  Although control of severe pain is expected in surgical intervention for GN, lower cranial nerves are easily damaged because of their fragility, even in MVD. IONM including pharyngeal and vagal MEPs appears very useful for avoiding postoperative sequelae during MVD for GN.
authors: Department of Neurosurgery, Nara Medical University, Kashihara, Japan.
authors: Yasushi
authors: Y
authors: Motoyama
authors: Department of Neurosurgery, Nara Medical University, Kashihara, Japan.
authors: Ichiro
authors: I
authors: Nakagawa
authors: Department of Central Laboratory, Nara Medical University, Kashihara, Japan.
authors: Tsunenori
authors: T
authors: Takatani
authors: Department of Neurosurgery, Nara Medical University, Kashihara, Japan.
authors: Hun-Soo
authors: HS
authors: Park
authors: Department of Neurosurgery, Nara Medical University, Kashihara, Japan.
authors: Yukiko
authors: Y
authors: Kotani
authors: Department of Neurosurgery, Nara Medical University, Kashihara, Japan.
authors: Yoshitaka
authors: Y
authors: Tanaka
authors: Ohnishi Neurological Centre, Akashi, Japan.
authors: Pritam
authors: P
authors: Gurung
authors: Department of Neurosurgery, Nara Medical University, Kashihara, Japan.
authors: Young-Soo
authors: YS
authors: Park
authors: Department of Neurosurgery, Nara Medical University, Kashihara, Japan.
authors: Hiroyuki
authors: H
authors: Nakase
keywords: Glossopharyngeal neuralgia; intraoperative neurophysiological monitoring; lower cranial nerves; microvascular decompression