RESUMO
This article reviews the Montreal experience of hearing preservation in acoustic neuroma surgery. The medical records since 1995 of 36 patients who underwent acoustic neuroma extirpation with the intent to preserve hearing were examined. Intraoperative monitoring was conducted using auditory brainstem response measurement with electrocochleography via a transtympanic electrode. The role of intraoperative monitoring in guiding surgical technique and its correlation with postoperative hearing outcome are discussed. A review of the literature regarding hearing preservation in acoustic neuroma surgery is included.
Assuntos
Transtornos da Audição/prevenção & controle , Neuroma Acústico/fisiopatologia , Neuroma Acústico/cirurgia , Complicações Pós-Operatórias/prevenção & controle , Adulto , Audiometria de Resposta Evocada , Eletrodos , Potenciais Evocados Auditivos do Tronco Encefálico , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Intraoperatória , Neuroma Acústico/patologia , Estudos Retrospectivos , Resultado do TratamentoRESUMO
The corpus callosum, the principal neocortical commissure, allows for the interhemispheric transfer of lateralized information between the hemispheres. The aim of the present experiment was to study callosal transfer of auditory information in the cat, with particular reference to its contribution to sound localization. The corpus callosum was approached under direct visual control, and axonic responses were recorded under light anesthesia using glass micro-pipettes. Results showed that auditory information is transmitted in the posterior portion of the callosum. Diotic presentations, in which interaural time delay was manipulated, indicated that, for a large number of fibers, the largest excitatory or inhibitory interactions were obtained at null interaural time delay, a condition which supports the notion of a callosal contribution to auditory midline fusion. However, an important number of callosal fibers was also found to be excited maximally at specific, non-zero interaural time delays, suggesting that they preferred sounds situated at spatial locations other than the midline. The results are discussed in relation to those obtained electrophysiologically for the visual and somesthesic modalities and in terms of results obtained in human and animal behavioral experiments.
