[Imaging of Cochlear Structures by Optical Coherence Tomography (OCT). Temporal bone experiments for an OCT-guided cochleostomy technique].
BACKGROUND
Optical Coherence Tomography (OCT) is a relatively new imaging technique, which provides scans similar to sonography on an optical base. We questioned whether OCT may be helpful in optimizing anatomical orientation in cochlear implant (CI) surgery. In a study on temporal bone specimens we tested, whether OCT provides information about the cochlear topography, particularly in situations, when for cochleostomy the bony otic capsule is already opened but the membranous endosteal layer is still intact.


METHODS
OCT was performed on five human temporal bone preparations, in which the cochleostomy was carried out still leaving the endosteum covering the fluid-filled inner ear intact. A prototype of operating microscope was used, in which a spectral-domain OCT (SD-OCT) with a central wavelength of 840 nm was integrated.


RESULTS
On all scans, OCT supplies information about inner ear structures, such as the lateral attachment of the basilar membrane dividing the scalae. Even delicate structures like the Reissner's membrane could be identified in one case.


CONCLUSIONS
This pilot study clearly documents the possibility to identify inner ear structures, especially the site of the scala tympani while its enveloping membranes are still intact. These findings may have an impact on cochlear implant surgery, especially as an orientation guide to localize the scala tympani precisely before opening the fluid-filled inner ear.
Pau
H W
HW
Klinik und Poliklinik für Hals-Nasen-Ohrenheilkunde, Kopf- und Halschirurgie Otto Körner der Universität Rostock, Rostock. hans-wilhelm.pau@med.uni-rostock.de
Lankenau
E
E
Just
T
T
Hüttmann
G
G
D019929:Cochlear Implantation / Q000295:instrumentation / Q000379:methods; D003054:Cochlear Implants; D006309:Hearing; D006652:Histological Techniques; D006801:Humans; D010865:Pilot Projects; D012533:Scala Tympani / Q000033:anatomy & histology; D013701:Temporal Bone / Q000033:anatomy & histology; D041623:Tomography, Optical Coherence