title: Preservation of the saccular nerve and of the vestibular evoked myogenic potential during vestibular schwannoma surgery.
abstract: OBJECTIVE
  The aim of the study was to present a case report demonstrating that vestibular evoked myogenic potentials originate from the saccular nerve.
  
  
  METHODS
  Retrospective case review.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  Vestibular evoked myogenic potentials are shown before and after operation in a patient with a surgically confirmed superior vestibular schwannoma (1.3 cm).
  
  
  METHODS
  Preoperative and postoperative audiometry, auditory brainstem response, caloric test, vestibular evoked myogenic potentials, and magnetic resonance imaging outcomes. RESULTS On preoperative audiometry, slight sensorineural hearing loss with normal auditory brainstem response could be detected. Caloric tests showed a reduced response of the right labyrinth. Vestibular evoked myogenic potentials were normal. The tumor was removed via a combined retrosigmoid and partial labyrinthectomy approach with the removal of the posterior semicircular canal. The facial, auditory, and inferior semicircular nerves were anatomically preserved. Postoperative audiometry revealed preservation of hearing and vestibular evoked myogenic potentials; caloric responses were now absent.
  
  
  CONCLUSIONS
  The combined retrosigmoid and partial labyrinthectomy approach represents an ideal condition to study the influence of the saccular nerve on the origin of the vestibular evoked myogenic potentials. The maintenance of the vestibular evoked myogenic potential responses in our patient supports the concept that the vestibular evoked myogenic potential originates in the saccule and is transmitted in the saccular nerve.
authors.affiliation: ENT Department, University La Sapienza, Rome, Italy. giuseppemagliuloorl@yahoo.com
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Magliulo
authors.forename: Mario
authors.initials: M
authors.lastname: Gagliardi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ciniglio Appiani
authors.forename: Raffaello
authors.initials: R
authors.lastname: D'Amico
mesh_terms: D001301:Audiometry, Pure-Tone; D002150:Caloric Tests; D003391:Cranial Nerves / Q000502:physiology*; D007758:Ear, Inner / Q000601:surgery; D005071:Evoked Potentials / Q000502:physiology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D007430:Intraoperative Care; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D009464:Neuroma, Acoustic / Q000150:complications / Q000473:pathology / Q000601:surgery*; D013506:Otologic Surgical Procedures / Q000379:methods; D011182:Postoperative Care; D011300:Preoperative Care; D012189:Retrospective Studies; D012444:Saccule and Utricle / Q000294:innervation*; D014722:Vestibule, Labyrinth / Q000502:physiology*