Round window membrane visibility related to success of hearing preservation in cochlear implantation

Abstract

Objectives: This study was designed to evaluate the relationship between the degree of round window membrane (RWM) exposure and hearing outcome.

Materials and methods: Forty-six ears with cochlear implantation (CI) were enrolled. The degree of RWM exposure was divided into Grade I (<25%), Grade II (25–50%), and Grade III (>50%). The hearing outcomes were evaluated at 1.5 and 12 months postoperatively.

Results: Twenty-seven ears were Grade I, 13 were Grade II, and 6 were Grade III. RW approach was used in all ears of Grades II and III and 20 ears of Grade I and cochleostomy was used in 7 ears of Grade I. The pattern of bony overhang was multidirectional in 41 ears. Threshold shift significantly decreased proportional to the increase of RWM exposure after CI. The mean RWM exposure was 32.1 ± 24.4% in ears with more than partial preservation (n = 17), and 13.3 ± 11.7% in the other ears (n = 6) at 12 months post-CI (p = .061). Age at CI differed significantly between ears that had more than partial preservation and the other ears at 1.5 months post-CI.

Conclusions and significance: Degree of RWM exposure and age at CI might be factors predicting hearing outcome after CI using the RW approach.

Chinese abstract

目的：探讨圆窗膜（RWM）暴露程度与听力结果的关系。

材料与方法：对具人工耳蜗植入（CI）的46个耳进行研究。RWM暴露程度分为一级（<25%）、二级（25-50%）和三级（>50%）。术后1.5个月和12个月对听力结果进行评估。

结果：27个耳为一级, 13个耳为二级, 6耳为三级。二、三级各耳和一级的20个耳均采用RW入路；一级的7个耳采用耳蜗造口术。41个耳呈多向骨垂。在CI之后, 随着RWM暴露量的增加, 阈值偏移明显减少。CI之后12个月, 大于部分保存的耳（n = 17）的平均RWM暴露率为32.1 ± 24.4%, 其他耳朵为13.3 ± 11.7%（n = 6）。CI之后1.5个月, 大于部分保存的耳朵和其他耳朵在植入时的年龄有显著差异。

结论和意义：RWM暴露程度和CI年龄可能是预测RW入路CI植入术后听力结果的因素。

Keywords:

• Cochlear implantation
• round window membrane
• ‘soft surgery’
• hearing preservation

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning (NRF-2018R1A1A1A05023057). This work was supported by the faculty research fund of Ajou University School of Medicine.