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Radiology for cochlear implants

Published online by Cambridge University Press:  29 June 2007

R. F. Gray*
Affiliation:
Cambridge
R. A. Evans
Affiliation:
Cambridge
C. E. L. Freer
Affiliation:
Cambridge
H. E. Szutowicz
Affiliation:
Cambridge
G. F. Maskell
Affiliation:
Cambridge
*
Mr. R. F. Gray F.R.C.S., Department of Otolaryngology, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK.

Abstract

One fifth of patients selected for cochlear implants have such bony irregularities in the cochlear duct that full insertion of a multichannel electrode array is impossible. Three cases of cochlear deafness are presented where pre- and post-operative radiology played an important part in the management.

Standard CT at 2 mm cuts is compared with ultra high resolution CT at 1 mm cuts. The pitfall of poor definition is that the inexperienced surgeon may find himself unexpectedly drilling out an obliterated cochlear duct. Sections 30 degrees caudal to Reid's infra orbito-meatal base line at 1 mm intervals give maximum information for minimum radiation.

Plain films show the placement of individual platinum electrode contacts in relation to the spiral ‘frequency map’ of the cochlea. This is vital information for the audiologist who has to route specific frequencies to specific sites within the ear for a good hearing result.

Type
Main Articles
Copyright
Copyright © JLO (1984) Limited 1991

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Footnotes

Paper presented at the Second International Implant Symposium, Iowa City, 4-9 June 1990.

References

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