Acoustic neuroma surgery: Absent auditory brainstem response does not contraindicate attempted hearing preservation

Abstract

Absent ABR waveforms have not been a negative prognostic sign regarding hearing preservation. CNAP monitoring is possible in these patients and likely helps to minimize iatrogenic cochlear nerve trauma. Patients with no ABR waveforms have hope of hearing preservation and even improvement following acoustic neuroma resection performed utilizing CNAP monitoring and hearing preservation surgical techniques.

Hearing preservation and intraoperative auditory brainstem response and cochlear nerve compound action potential monitoring in the removal of small acoustic neurinoma via the retrosigmoid approach

“…The latency of CNAP elongated gradually during microsurgical tumour removal, and the latency after microsurgical tumour removal was significantly elongated compared with the baseline. CNAP is the summation of individual nerve fibre signals in the cochlear nerve 20 36. Tumour compression of the cochlear nerve causes the conduction block of individual nerve fibre15 22 33 and the desynchronisation of individual nerve fibre signals 20 36.…”

“…CNAP is the summation of individual nerve fibre signals in the cochlear nerve 20 36. Tumour compression of the cochlear nerve causes the conduction block of individual nerve fibre15 22 33 and the desynchronisation of individual nerve fibre signals 20 36. The desynchronisation results in a decreased amplitude or even the disappearance of CNAP 36.…”

“…Tumour compression of the cochlear nerve causes the conduction block of individual nerve fibre15 22 33 and the desynchronisation of individual nerve fibre signals 20 36. The desynchronisation results in a decreased amplitude or even the disappearance of CNAP 36. Surgical decompression of the cochlear nerve can dissolve the desynchronisation, resulting in the increased amplitude after tumour removal 18 19.…”

Hearing aids in patients with vestibular schwannoma: Interest of the auditory brainstem responses

“…This limitation should be noted, where future studies including more patients with different stages are necessary to confirm our findings. Clinical, electrophysiological and histological studies hypothesised that an absence of ABR in cases of VS could result from compression by the schwannoma, in turn causing neural conduction block . One study investigated cortical auditory responses in patients with a VS and no ABR; positive cortical responses were noted, such as the N1 m and 40‐Hz ASSR.…”

Cost‐Utility Analysis of Pediatric Cochlear Implantation

“…To the Editor, I read with great interest the article by Roberson et al 1 on acoustic neuroma surgery in the June 1999 issµe of The Laryn.goscope. I would like to share my experience by reporting a case similar to the one described by Roberson et al This is a case of combined acoustic and jugular foramen neurinoma in a patient with neurofibromatosis type 2.…”