ABSTRACT
Objective:To investigate the value of brainstem auditory evoked potential (BAEPs) combined with cochlear electrogram (ECochG) monitoring in the protection of auditory function during microvascular decompression (MVD) for patients with facial spasm (HFS).Methods:Clinical data of 908 patients with HFS who received MVD treatment in our hospital from January 2018 to December 2020 were retrospectively analyzed. The patients were divided into BAEPs group ( n=309), ECochG group ( n=301) and BAEPs+ECochG group ( n=298) according to the different methods of auditory nerve function monitoring. Waveform extraction rate, mean extraction time, amplitude, latency, intraoperative warning effect of 3 monitoring methods, as well as hearing status immediately after surgery and during follow-up were compared in patents from the 3 groups. Results:(1) The overall waveform extraction rate in ECochG group and BAEPs+ECochG group was significantly higher than that in BAEPs group, and the average waveform extraction time in ECochG group and BAEPs+ECochG group was significantly shorter than that in BAEPs group ( P<0.05). The amplitude of compound action potential (CAP) wave in ECochG group was significantly higher than that of V wave in BAEPs group, and the latency of CAP wave was also significantly earlier than that of V wave ( P< 0.05). (2) A total of 48 patients of the 288 patients in the BAEPs group showed warning signs; a total of 73 of the 292 patients in the ECochG group showed warning signs; and a total of 65 of the 292 patients in the BAEPs+ECochG group showed warning signs. (3) There was significant difference in hearing grading (American Association of Otolaryngology Head and Neck Surgery [AAO-HNS] grading) among the 3 groups immediately after surgery ( H=18.041, P=0.000), and the average rank suggested that the hearing of patients in the BAEPs+ECochG group was superior to the other two groups. All patients were followed up for an average of 15 months (ranged 3-24 months); there was still a significant difference in AAO-HNS grading among the 3 groups ( H=29.625, P=0.000), and the hearing of patients in the BAEPs+ECochG group was still superior to the other two groups. Conclusion:The combined application of ECochG and BAEPs monitoring can reflect the changes of intraoperative hearing impairment comprehensively, accurately and timely, which is of great significance for the protection of auditory function in HFS patients during MVD.
ABSTRACT
BACKGROUND AND OBJECTIVES: Despite the continued research on the pathology of Meniner's disease, it still remains largely uncertain. Since endolymphatic hydrops is known to occur in Meniner's disease, this study was conducted with experimentally induced endolymphatic hydrops. We evaluated the usefulness of click evoked otoacoustic emissions (CEOAE) and electro-cochleogram (ECoG) in studying endolymphatic hydrops. MATERIALS AND METHODS: Animal endolymphatic hydrops was induced in giunea pigs by mechanically obliterating the right endolympatic sacs and their ducts. The left ears were used as controls. In twelve weeks following the induction of endolymphatic hydrops, CEOAE and ECoG were measured. RESULTS: 1) The endolymphatic hydrops induced group responded to CEOAE with 33.3% positivity, whereas the control group responded with 87.6% positivity. The echo response and reproducibility were significantly low in the endolymphatic hydrops group, for which the negative echo response was more pronounced. For the CEOAE positive endolymphatic hydrops group, the average peak frequency of the response curves was shifted significantly to a higher frequency. 2) The tone burst stimulated ECoG response showed the permanant summating potential. The tone bursts with the intensity of 95 dB and frequencies of 4 or 8 kHz were found to be suitable stimuli for the study of endolymphatic hydrops. On click stimulation, the latency of the first negative peak (AN1) in the endolymphatic hydrops group was prolonged. The ratios of the summating potential amplitude to the action potential were observed to be significantly high.
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Animals , Action Potentials , Ear , Endolymphatic Hydrops , Guinea Pigs , Guinea , Pathology , SwineABSTRACT
Objective To study the characteristics of hearing loss caused by local microcirculatory disorders in the cochlea apical part of guinea pigs. Methods The local microcirculatory disorders in the cochlea apical part of guinea pigs were caused by photochemical reaction. Morphological changes were observed by light microscope. The CAP - N1 amplitude, CAP - N1 latency, CAP - N1 threshold shift and CM amplitude which were evoked by short tone burst were recorded by Madsen 2250. Re- sults Histopathological changes showed that microthrombosis in the capillaries of stria vascularies and spiral ligment were located in the apical and third turn of cochlea. The CAP - N1 amplitude, CAP - N1 latency, CAP-N1 threshold shift and CM amplitude showed that the hearing loss was remarkable in the low - range frequencies. Conclusion When the local microcirculatory disor- ders in the cochlear apical part took place, the hearing loss was more marked in the low - range frequencies.