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Narrow Nerve. surgical outcome diagnostic accuracy. speech awareness. limited cost effectiveness. candidacy. right ear – cochlear nerve stenosis. SCC. Normal Internal Auditory Canal. Cochlea. FN. SCC. Normal Internal Auditory Canal. Normal IAC. SVN. CN. VCN. Cochlea. VN.
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Narrow Nerve • surgical outcome • diagnostic accuracy speech awareness limited cost effectiveness candidacy right ear – cochlear nerve stenosis
SCC Normal Internal Auditory Canal Cochlea
FN SCC Normal Internal Auditory Canal Normal IAC SVN CN VCN Cochlea VN IVN
Stenotic IAC – Functional Nerves? Stenotic IAC FN SVN ? CN IVN
1µV 1ms 1µV 1ms Cochlear Nerve Canal Diameter Normal* Moderate Stenosis Amplitude (µV) Critical Stenosis *Propst et al 2006 Laryngoscope Time (ms)
Narrow Nerve • surgical outcome • diagnostic accuracy speech awareness limited cost effectiveness 1.5 mm candidacy
Current Opinion • variable outcome • less than 1.5 mm nerve – very poor performance • high rate of unwanted stimulation • possible role for ABI