Insertion trauma of a new cochlear implant electrode: evaluated by histology in fresh human temporal bone specimens

Abstract

Background

Combining acoustic and electrical stimulation has been successfully used in patients with low-frequency residual hearing. Electrode insertion trauma, such as electrode translocation could result in loss of residual hearing.

Objectives

The aim of the study is to evaluate the LCI-20PI electrode array insertion trauma to the intra-cochlear structures in fresh human temporal bone specimens.

Materials and methods

The LCI-20PI electrode arrays were inserted into scalae tympani through round window membrane in 10 cochleae from ten fresh human cadavers. The intracochlear trauma was evaluated histologically by a scale of 0–4: 0 – no observable trauma, 1 – elevation of basilar membrane, 2 – rupture of basilar membrane or spiral ligament, 3–dislocation into scala vestibuli and 4 – fracture of modiolus or osseous spiral lamina. The insertion depth was measured by radiography.

Results

Histological results revealed no observable trauma in seven specimens; basal membrane elevation and rupture in two specimens; the electrode array misled into scala vestibuli in one specimen. The insertion depth varied from 228° to 288°.

Conclusions and significance

The insertion of the LCI-20PI electrode arrays caused no trauma in the majority of the fresh temporal bone specimens. No translocation of the electrode arrays from the scala tympani to the scala vestibuli was observed.

Chinese abstract

背景：声波和电刺激相结合已成功用于低频残留听力患者。电极插入创伤（例如电极移位）可能会导致残余听力丧失。

目的：本研究的目的是评估LCI-20PI电极阵列对新鲜人颞骨标本的耳蜗内结构的创伤。

材料和方法：将LCI-20PI电极阵列经过10具新鲜尸体的10个耳蜗中的圆窗膜插入鼓膜中。耳蜗内创伤的组织学评分为0–4：0 –无可观察到的创伤；1 –基底膜抬高；2 –基底膜或螺旋韧带破裂；3 –脱位至耳蜗上前庭；4 –耳蜗锥形中轴或骨质螺旋状叶片破裂。插入深度通过射线照相术测量。

结果：组织学结果显示, 在七个标本中没有可观察到的创伤；两个标本的基底膜升高和破裂；电极阵列在一个样本中误入耳蜗上前庭。插入深度从228⁰到288⁰不等。

结论和意义：LCI-20PI电极阵列的插入对大多数新鲜的颞骨标本没有造成损伤。没有观察到电极阵列从鼓室到前庭的移位。

Keywords:

• Cochlear implant
• electrode
• temporal bone
• histology

Disclosure statement

The authors report no conflicts of interest.

Additional information

Funding

This work was supported by National Health Commission under The Research Special Fund for Public Welfare Industry of Health (201202001).