Reliability of cone beam computed tomography in scalar localization of the electrode array: a radio histological study

Abstract

Postoperative imaging plays a growing role in clinical studies concerning prognostic factors in cochlear implantation. Indeed, intracochlear position of the cochlear implant has recently been identified as a contributor in functional outcomes and radiological tools must be accurate enough to determine the final placement of the electrode array. The aim of our study was to validate cone beam computed tomography as a reliable technique for scalar localization of the electrode array. We performed therefore a temporal bone study on ten specimens that were implanted with a perimodiolar implant prototype. Cone beam reconstructions were performed and images were analyzed by two physicians both experienced in cochlear implant imaging, who determined the scalar localization of the implant. Temporal bones then underwent histological control to document this scalar localization and hypothetical intracochlear lesions. In four cases, a dislocation from scala tympani to scala vestibuli was suspected on cone beam reconstructions of the ascending part of the basal turn. In three of these four specimens, dislocation in pars ascendens was confirmed histologically. In the remaining temporal bone, histological analysis revealed an elevation with rupture of the basilar membrane. Histological assessment revealed spiral ligament tearing in another bone. We conclude that cone beam is a reliable tool to assess scalar localization of the selectrode array and may be used in future clinical studies.

Effects of Electrode Array Length on Frequency-Place Mismatch and Speech Perception with Cochlear Implants

“…Theoretical positions of scala tympani and scala vestibuli were determined based on previous studies [Lecerf et al, 2011;Marx et al, 2014]. On midmodiolar reconstructions, scala tympani was localized in the inferior part of a half-turn section of the cochlea and scala vestibuli in the superior part.…”

Assessment of Cochlear Trauma During Cochlear Implantation Using Electrocochleography and Cone Beam Computed Tomography

“…Besides high-resolution computed tomography (3,12), cone beam computed tomography (CBCT) (13) has gained increasing support as it is a quick procedure and the radiation dose seems to be lower than with high-resolution computed tomography (14). Furthermore, previous reports have shown high reliability for correctly detecting scalar position of the electrode array within the basal turn of the cochlea (15)(16)(17)(18).…”

Radiologic and Functional Evaluation of Electrode Dislocation from the Scala Tympani to the Scala Vestibuli in Patients with Cochlear Implants

“…According to the histologic study of Marx et al, 11 the electrode position within the cochlea can be reliably identified. When one knows that in multiplanar reconstructions, the tympanic scala is basal and the vestibular scala is apical, the liquid-filled space is seen above the electrode array when the electrode is located correctly in the scala tympani.…”

“…Due to the high resolution and low influence of metal artifacts, CBCT has emerged as a reliable technique in scalar localization of the electrode array, showing a sensitivity of 100% and specificity of 90%. 11 According to Aschendorff et al, 1 the intracochlear localization of the electrode has a significant impact on speech recognition. Insertion of the electrode array in the scala tympani is associated with a better outcome than insertion in the scala vestibuli.…”