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Electrically Evoked Stapedius Reflex Measurements in Cochlear Implantation and Its Application in the Postoperative Fitting Process

Measuring the electrically evoked stapedius reflex during the fitting of cochlear implants (CIs) provides a reliable estimation of maximum comfort levels, ...

Technical University of Dresden

The development of a procedure for the measurement of insertion depth angles of cochlear implant electrode arrays based on flat-panel computed tomography (FPCT) and the application of this technique to in vivo postoperative images.

In vivo measurements of the insertion depth of cochlear implant arrays using flat-panel volume computed tomography.

The aim of the study is to investigate the insertion depth angles for different types of electrode arrays and its variability depending on the individual cochlear size.

Insertion depth angles of cochlear implant arrays with varying length: a temporal bone study.

Beside the cochlear size, the linear insertion depth (LID) influences the insertion depth angle of cochlear implant electrode arrays. For the specific implant CI422 the recommended LID is not fixed but can vary continuously between 20 and 25 mm. In the current study, the influence of cochlea size and LID on the final insertion depth angle was investigated to develop a prediction tool for the insertion depth angle by means of cochlea diameter and LID. Preoperative estimation of insertion depth angles might help surgeons avoid exceeding an intended insertion depth, especially with respect to low-frequency residual hearing preservation. Postoperative, high-resolution 3D-radiographs provided by Flat Panel Computed Volume Tomography (FPCT) were used to investigate the insertion depth angle in 37 CI422 recipients. Furthermore, the FPCT images were used to measure linear insertion depth and diameter of the basal turn of the cochlea. A considerable variation of measured insertion depth angles ranging from 306° to 579° was identified. The measured linear insertion depth ranged from -18.6 to 26.2 mm and correlated positively with the insertion depth angle. The cochlea diameter ranged from 8.11 to 10.42 mm and correlated negatively with the insertion depth angle. The results suggest that preoperatively measured cochlea diameter combined with the option of different array positions by means of LID may act as predictors for the final insertion depth angle.

Annett Franke-Trieger

Technical University of Dresden

Electrically Evoked Stapedius Reflex Measurements in Cochlear Implantation and Its Application in the Postoperative Fitting Process