Evaluating round window niche visibility in cochlear implantation: anatomical insights and electrode insertion strategies.

Purpose: Cochlear implantation (CI) surgery is essential for restoring hearing in individuals with severe sensorineural hearing loss. Accurate placement of the electrode within the cochlea is essential for successful auditory outcomes and minimizing complications. This study aims to analyze the relationship between the round window niche (RWN) alignment, its visibility during surgery, and the impact on surgical techniques and outcomes.
Methods: A retrospective study was conducted, examining high-resolution computed tomography (CT) scans of the temporal bone from 103 patients who underwent CI. RWN visibility was assessed using the St. Thomas Hospital (STH) classification. Anatomical parameters such as the angles of RWN alignment relative to the lateral semicircular canal (LSCC) plane and the distances to the facial nerve were measured and recorded.
Results: The analysis revealed that RWN alignment angles did not significantly correlate with RWN visibility. However, specific anatomical distances, such as the anteroposterior distance between the round window membrane (RWM) and the facial nerve, were significantly associated with improved RWN visibility.
Conclusion: Preoperative knowledge of RWN anatomy, particularly its relationship with the facial nerve, can reduce the complexity of CI surgery. Understanding these anatomical variations is essential for optimizing surgical outcomes. Future research should explore additional cochlear axis orientations to enhance surgical techniques and improve visibility assessments during CI procedures.
Competing Interests: Declarations. Conflicts of Interest: All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript. Ethics Approval: Ethics committee approval was obtained from Local Scientific Research Ethics committee of istanbul educational and research hospital according to Helsinki Declaration with ethical committee approval document details: 2967/ 05.11.2021 with document code 2011-KAEK-50. Consent to Participate: Informed prior written consent to participate in the study was obtained from the parents or legal guardian of the children. Consent to Publish: The authors affirm that human research participants provided informed consent for publication of the images in all figures.
(© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)