Initial investigation of the efficacy and biosafety of sodium hyaluronate (healon) as an aid to electrode array insertion

Abstract

Stimulation of residual neural elements by electrodes inserted into the cochlea to produce the perception of speech and environmental sounds in profoundly deaf people is a fundamental aim of cochlear implantation. The multiple-channel cochlear implant utilizes the tonotopic arrangement of the organ of Corti to also achieve place pitch perception by stimulating different electrode bands. It may be possible to improve the range of pitches perceived by present cochlear implant patients by inserting the electrode array more deeply. To help achieve this, investigators have used sodium hyaluronate as a lubricant for electrode insertions. 1 It was felt deeper insertions were produced with sodium hyaluronate. Before introducing this substance as part of the surgical protocol for the Melbourne Cochlear Implant Clinic, it was decided to investigate its efficacy in aiding deeper insertions of the electrode. In addition, it was also necessary to determine if sodium hyaluronate, in conjunction with cochlear implantation, had adverse effects on the inner ear. This study was undertaken to address these issues.