title: Intraoperative monitoring of hearing during cerebellopontine angle tumor surgery using transtympanic electrocochleography.
abstract: OBJECTIVE
  To investigate the use of transtympanic electrocochleography (TT-ECochG) analyzed on-line by a detector strategy software that made possible automatic extraction of TT-ECochG components intraoperatively in real-time domain.
  
  
  METHODS
  Fifteen patients with cerebellopontine angle tumor among 50 patients were included in this study.
  
  
  METHODS
  All subjects were operated on via middle fossa or retrosigmoid approach. Pure-tone average (PTA) was measured at 0.5, 1.0, and 2.0 kHz, and calculations were performed before and after surgery. Auditory function was monitored intraoperatively via TT-ECochG, and analyzed data were displayed on-line.
  
  
  METHODS
  TT-ECochG changes in morphology were described. Postoperative PTA elevation level correlated with TT-ECochG morphology changes occurring intraoperatively.
  
  
  RESULTS
  Analyzed on-line, TT-ECochG data were displayed as first negative peak of compound action potential amplitude and latency in time domain every 3 to 5 seconds. A good correlation between postoperative PTA elevation and TT-ECochG morphology changes was showed (Spearman rank test, R = +0.93; t(N-2) = 9.00; p < 0.0001).
  
  
  CONCLUSIONS
  TT-EcochG seemed to effectively mirror even minimal changes in auditory function during intraoperative monitoring in real-time domain. Developed strategy of on-line analysis makes the intraoperative hearing status assessment faster and easier.
authors.affiliation: Department of Otolaryngology, Medical University of Warsaw, Warsaw, Poland. morawski@neurotology.pl
authors.forename: Krzysztof F
authors.initials: KF
authors.lastname: Morawski
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Niemczyk
authors.forename: Jorge
authors.initials: J
authors.lastname: Bohorquez
authors.forename: Andrzej
authors.initials: A
authors.lastname: Marchel
authors.forename: Rafael E
authors.initials: RE
authors.lastname: Delgado
authors.forename: Ozcan
authors.initials: O
authors.lastname: Ozdamar
authors.forename: Fred F
authors.initials: FF
authors.lastname: Telischi
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D001300:Audiometry, Evoked Response; D002528:Cerebellar Neoplasms / Q000601:surgery*; D002530:Cerebellopontine Angle / Q000601:surgery*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D011199:Potentiometry; D014432:Tympanic Membrane / Q000502:physiology*