Fig 1.
Overview of implanted electrode arrays which were included into this study. Note that the CMD group consists of FLEX16 electrode arrays and partial insertions of FLEX24 and FLEX28 electrodes).
Fig 2.
Spline measurement with OsiriX MD.
Visualization of lateral wall tracing in OsiriX MD in top (A) and side views (B, C).
Fig 3.
Complete segmentation of the lateral wall.
Visualization of a completed lateral wall tracing in OsiriX MD (A, B) with the additional display of the enrolled path (C) for which the length is computed automatically.
Fig 4.
Measurement of global cochlea dimensions.
Visualization of measurements of A (defined as the distance from the round window through the modiolus to the opposite wall of the cochlea) and B (maximal distance orthogonal to A).
Fig 5.
Inclusion of postoperative imaging analysis.
(A) Postoperatively, marker points were placed in the center of the round window and along the inserted electrode array in the middle of the respective contact artefacts, and the corresponding insertion angle was measured. (B) The latter value was then used within the corresponding preoperative imaging data to determine the length along the lateral wall up to the insertion angle.
Fig 6.
Histograms of (A) measured and (B) estimated CDL values. (C) comparison of individual CDL measurements and estimations.
Fig 7.
Distribution of electrode specific CI outcomes.
(A) IEL and CCL distribution as well as (B) CC ranges for the different electrode array groups.
Fig 8.
(A) Depiction of the CCL range computed for a fully inserted (+/-5%) FLEX28 array, (B) visualization of the corresponding CDL indication ranges for FLEX24, FLEX28 and FLEXSoft electrode arrays.
Table 1.
Indication range for the FLEX electrodes.
Fig 9.
(A) Histogram of the organ of Corti (OC) derived by Hardy and Lee (red) and MHH data (black), (B) Histogram of calculated OC length for MHH data with electrode lengths for FLEX24, FLEX28 and FLEXSoft (+/- 5%).
Fig 10.
CDL identification of FLEX28 candidates.
(A) the comparison of measurement and estimation-based identifications of FLEX28 candidates resulted in (B) correct identifications in 66% of the analyzed anatomies using Escudé’s method.
Table 2.
Correct identification of cochlea length.
Fig 11.
Extended indication range for MED-EL FLEX28.
Structure preservation indication range for the FLEX28 array which could have been fully inserted in 76% of the investigated cases.