The value of digital volume tomography in assessing the position of cochlear implant arrays in temporal bone specimens.
OBJECTIVE
Radiological evaluation of the position of cochlear implant (CI) devices is an upcoming method for quality control after CI surgery. First, results of imaging of the middle and inner ear with digital volume tomography (DVT) show considerable advantages such as exceptional image quality, thin slice thickness, and low radiation dose. The aim of this study was to evaluate whether DVT is an appropriate method for postoperative imaging of CI patients and to identify the exact position of the implant array within the cochlear by multiple measurements.


METHODS
Thirteen formalin-fixed temporal bone specimens were implanted with a CI array and scanned in DVT. To determine the exact electrode position, these specimens were ground and stained for microscopic measurements. The measurements on grindings acted as a referee and were compared with the measurements in DVT scans. The statistical analysis between the two measurement protocols was performed using the Bland-Altman method.


RESULTS
Best achievable agreement between DVT scans and histological reference was shown. Mean differences between DVT and grindings from -1.55 to -65.40 microm were calculated. All means are within the region of accuracy. General positioning of the implant into the cochlea could be verified in all specimens. The exact position of the implanted array within the cochlear scalae could be recognized correctly in 11 of 13 cases in DVT. It was possible to identify shiftings between the tympanic and vestibular scalae in all cases.


CONCLUSIONS
DVT seems to be a convenient technique for postoperative position control after cochlear implantation.
Kurzweg
Thiemo
T
Department of Otolaryngology, Head and Neck Surgery, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany.
Dalchow
Carsten V
CV
Bremke
Martin
M
Majdani
Omid
O
Kureck
Ingo
I
Knecht
Reinald
R
Werner
Jochen A
JA
Teymoortash
Afshin
A
D016477:Artifacts; D002102:Cadaver; D003051:Cochlea / Q000000981:diagnostic imaging* / Q000293:injuries; D003054:Cochlear Implants / Q000009:adverse effects*; D004432:Ear, Middle / Q000000981:diagnostic imaging* / Q000293:injuries; D004566:Electrodes / Q000009:adverse effects; D005557:Formaldehyde; D006801:Humans; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011786:Quality Control; D015203:Reproducibility of Results; D013701:Temporal Bone / Q000000981:diagnostic imaging* / Q000293:injuries; D055114:X-Ray Microtomography / Q000379:methods* / Q000592:standards
D005557:Formaldehyde