Kale Sushrut, Cervantes Vanessa M, Wu Mailing R, Pisano Dominic V, Sheth Nakul, Olson Elizabeth S
Department of Otolaryngology-Head & Neck Surgery, Columbia University, New York, NY 10032, USA.
Department of Otolaryngology-Head & Neck Surgery, Columbia University, New York, NY 10032, USA.
Hear Res. 2014 Aug;314:33-41. doi: 10.1016/j.heares.2014.05.003. Epub 2014 May 29.
A cochlear implant (CI) restores partial hearing to profoundly deaf individuals. CI electrodes are inserted manually in the cochlea and surgeons rely on tactile feedback from the implant to determine when to stop the insertion. This manual insertion method results in a large degree of variability in surgical outcomes and intra-cochlear trauma. Additionally, implants often span only the basal turn. In the present study we report on the development of a new method to assist CI electrode insertion. The design objectives are (1) an automated and standardized insertion technique across patients with (2) more apical insertion than is possible by the contemporary methods, while (3) minimizing insertion trauma. The method relies on a viscous fluid flow through the cochlea to carry the electrode array with it. A small cochleostomy (∼100-150 um in diameter) is made in scala vestibuli (SV) and the round window (RW) membrane is opened. A flow of diluted Sodium Hyaluronate (also known as Hyaluronic Acid, (HA)) is set up from the RW to the SV opening using a perfusion pump that sets up a unidirectional flow. Once the flow is established an implant is dropped into the ongoing flow. Here we present a proof-of-concept study where we used this technique to insert silicone implants all the way to the cochlear apex in rats and gerbils. In light-microscopic histology, the implantation occurred without cochlear trauma. To further assess the ototoxicity of the HA perfusion, we measured compound action potential (CAP) thresholds following the perfusion of HA, and found that the CAP thresholds were substantially elevated. Thus, at this point the method is promising, and requires further development to become clinically viable.
人工耳蜗(CI)可使极重度聋患者恢复部分听力。CI电极通过手动插入耳蜗,外科医生依靠植入物的触觉反馈来确定何时停止插入。这种手动插入方法导致手术结果和耳蜗内创伤存在很大差异。此外,植入物通常仅跨越蜗底。在本研究中,我们报告了一种辅助CI电极插入的新方法的开发情况。设计目标是:(1)针对不同患者实现自动化和标准化的插入技术;(2)比当代方法能更向蜗顶插入;(3)同时将插入创伤降至最低。该方法依靠粘性流体流经耳蜗来携带电极阵列。在前庭阶(SV)制作一个小的蜗窗造口(直径约100 - 150微米),并打开圆窗(RW)膜。使用灌注泵从RW到SV开口建立稀释的透明质酸钠(也称为透明质酸,HA)的流动,从而形成单向流。一旦建立流动,将植入物放入正在流动的液体中。在此我们展示一项概念验证研究,其中我们使用该技术将硅胶植入物一直插入大鼠和沙鼠的耳蜗顶端。在光学显微镜组织学检查中,植入过程未造成耳蜗创伤。为了进一步评估HA灌注的耳毒性,我们在灌注HA后测量复合动作电位(CAP)阈值,发现CAP阈值大幅升高。因此,目前该方法很有前景,但需要进一步发展才能在临床上可行。