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. 2024 Aug 12;13(16):4716.
doi: 10.3390/jcm13164716.

Influence of Cochlear Anatomy on Intraoperative Electrically Evoked Compound Action Potentials

Nawaf Fatani  1 , Yassin Abdelsamad  2 , Abdulrahman Alsanosi  1
Affiliations

Influence of Cochlear Anatomy on Intraoperative Electrically Evoked Compound Action Potentials

Nawaf Fatani et al. J Clin Med. .

Abstract

Objective: The electrically evoked compound action potential (ECAP) is an objective measure to indirectly assess spiral ganglion neurons. The ECAP provides inputs about the prognoses of cochlear implant (CI) recipients. Several factors such as cochlear morphology can affect ECAP measurements. This study aims to investigate the variation effect of cochlear parameters on intraoperative ECAP thresholds. Methods: This is a retrospective study on patients who underwent CI surgery with normal inner ear morphology at our center between 2017 and 2023. Cochlear anatomical parameters, including diameter (A value), width (B value), and height (H value), as well as cochlear duct length (CDL), were measured pre-operatively using OTOPLAN software (Version 3.0). Cochlear implant intraoperative objective measures were also collected. The correlation between the cochlear parameters and intraoperative objective measures was studied. Results: A total of 45 patients underwent cochlear implantation. The mean age was 2.4 ± 0.9 years. The mean CDL and cochlear coverage values were 33.2 ± 2.0 mm and 76.0 ± 5.7%, respectively. The ECAP threshold increased toward basal electrodes, with ECAP values as follows: apical 13.1 ± 3.8; middle 14.3 ± 3.7; and basal 15.6 ± 4.8. Additionally, the A, B, and H values showed a positive correlation with ECAP thresholds in different cochlear regions. The B value showed a significant moderate correlation with ECAP thresholds in the middle and basal electrodes but not in the apical electrodes. Conclusions: Cochlear anatomical parameters correlate with intraoperative ECAP thresholds. The B value showed a significant association with ECAP thresholds in the middle and basal electrodes. These findings could delineate the impact of the B value in CI and optimize electrode selection. Further research is required to study this correlation and its impact on postoperative outcomes.

Keywords: cochlear duct length; cochlear implant; cochlear implantation; evoked compound action potential.

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Conflict of interest statement

The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1
Figure 1
Cochlear parameters using OTOPLAN software, showing A value (green dots), B value (blue dots), and H value (red dots).
Figure 2
Figure 2
Correlation between cochlear parameters and significant electrode impedance measures.
Figure 3
Figure 3
Correlation between cochlear parameters and significant ECAP measures. ** means statistically significant.
Figure 4
Figure 4
Association between cochlear parameters and electrode impedance measures (β coefficients and p values).
Figure 5
Figure 5
Association between cochlear parameters and ECAP thresholds (β coefficients and p values). ** refers to statistically significant.
See this image and copyright information in PMC

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