Intraoperative monitoring of hearing during cerebellopontine angle tumor surgery using transtympanic electrocochleography.
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.
Morawski
Krzysztof F
KF
Department of Otolaryngology, Medical University of Warsaw, Warsaw, Poland. morawski@neurotology.pl
Niemczyk
Kazimierz
K
Bohorquez
Jorge
J
Marchel
Andrzej
A
Delgado
Rafael E
RE
Ozdamar
Ozcan
O
Telischi
Fred F
FF
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*