Correlation between the stereostructure of facial recess and the classification of round window membrane visibility - Research findings

Sep 30, 2026

Objectives examine how facial recess dimensions relate to selecting an electrode array insertion approach in cochlear implantation. This prospective single-center study includes 51 subjects (60 ears) across pediatric and adult groups, measuring horizontal distance and vertical height based on specific facial nerve landmarks. Results show no pediatric–adult differences in measured parameters, while ROC analysis identifies a horizontal distance d <1.95 mm as predictive of limited round window membrane visibility; vertical height h shows no correlation. Conclusion: horizontal distance determines RWM exposure classification, supporting round window insertion when d >1.95 mm.

LanguageEnglish

CategoryHealthcare

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Pages9

Reading Time23 min

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Abstract

Objectives

Study design and setting

Methods

Results

Conclusions

Introduction

Surgical approaches and rationale

Study aims

Material and methods

Inclusion and exclusion criteria

Yang et al. European Journal European Journal of Medical Research (2026) 31:25 [https://doi.org/10.1186/s40001-025-03611-2](https://doi.org/10.1186/s40001-025-03611-2 of Medical Research)[ of Medical Research](https://doi.org/10.1186/s40001-025-03611-2 of Medical Research) RESEARCH Open Access Correlation between the stereostructure of facial recess and the classification of round window membrane visibility Huimin Yang1, Yongqiang Zhao1, Hui Li 1 and Jianqiu Chen1* Abstract Objectives This study investigates the correlation between the dimensions of the facial recess (FR) and the selection of an electrode array insertion approach in cochlear implantation. Study design Prospective clinical study. Setting Single-center. Methods This study included 51 subjects (60 ears), comprising 30 pediatric and 30 adult ears, who underwent cochlear implantation. According to the St. Thoma’s Hospital (STH) classification criteria, two parameters were measured: (1) the horizontal distance (d) from the anterior edge of the vertical segment of the facial nerve (FN) to the posterior edge of the chorda tympani nerve (CTN), measured at a point 5 mm inferior to the short process of the incus; and (2) the vertical height (h) from the center of the electrode array insertion hole to the anterior edge of the vertical segment of the FN. Results No statistically significant differences in the d and h values were observed between the pediatric and adult cohorts (P> 0. 05) . Receiver operating characteristic (ROC) curve analysis indicated that a horizontal distance d of less than 1.95 mm between the anterior edge of the vertical segment of the FN and the posterior edge of the CTN predicted limited round window membrane (RWM) visibility, corresponding to Type IIA (50–100% exposure), Type IIB (0–50% exposure), or Type III (no exposure) classifications. In contrast, the vertical height h demonstrated no significant correlation with RWM visibility. Conclusions The horizontal distance of the facial recess is a determining factor for RWM exposure classification, whereas the vertical height is not. An exposure likelihood increases significantly when the horizontal distance exceeds 1.95 mm, thereby favoring electrode insertion via the round window approach. Keywords Facial recess, Facial nerve, Round window membrane, Cochlear implant Introduction Cochlear implantation is the most effective intervention for hearing and speech rehabilitation in individuals with severe-to-profound sensorineural hearing loss (SNHL) *Correspondence: Jianqiu Chen [jianqiuc2008@aliyun.com](jianqiuc2008@aliyun.com) 1 No. 960 Hospital of the Joint Service Support Force of the Chinese People’s Liberation Army, Jinan, China who receive insufficient benefit from hearing aids [1]. Commonly utilized surgical approaches for cochlearimplantation include the facial recess (FR) approach, the transcanal approach, and the suprameatal approach [2, 3]. Commonly utilized surgical approaches for cochlear implantation include the FR approach, the transcanal approach, the suprameatal approach, the endoscopic approach, the retro-facial approach, and robotic cochlear implantation [4, 5]. The FR approach remains the © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s

FAQs

What question does the study address about cochlear implantation?

It investigates whether the horizontal and vertical dimensions of the facial recess correlate with how round window membrane visibility is classified and thus with selecting the electrode insertion approach.

How were the facial recess parameters measured?

The horizontal distance d and vertical height h were measured using defined anatomical landmarks on HRCT-based assessment, including distances related to the facial nerve and chorda tympani nerve.

Which parameter was found to predict round window membrane visibility classification?

Horizontal distance d was predictive, with ROC analysis indicating that d <1.95 mm predicts limited RWM visibility categories, while vertical height h showed no significant correlation.

Sep 30, 2026

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