Soft cochlear implantation: rationale for the surgical approach

Abstract

Recent advances in cochlear implant technology have focused renewed attention on the preservation of residual hearing. The focus on preservation of residual hearing is driven by the concept of electroacoustic stimulation. This option depends on the insertion of a short cochlear implant electrode into the basal region of the cochlea while preserving native function in the apical region. The desire to preserve residual hearing has led to the development of the soft-surgery cochlear implantation technique. Here, the authors evaluate its various components. Avoiding entry of blood into the cochlea and the use of hyaluronate seem to be reasonably supported, whereas the use of topical steroids is unlikely to be beneficial. The site of entry into the cochlea, the use of contoured or straight devices, and the depth of insertion are also evaluated. The authors highlight the importance of systematic recording of outcomes and surgical events.

Figure 1.

Photograph of right temporal bone with the basal cochlea turn drilled out. The round window membrane (RWM) has been rotated inferiorly and outward for visualization but normally lies beneath and in the plane of the anterior-posterior directional. To safely enter the scala tympani, the cochleostomy needs to be performed anterior and inferior to the round window membrane (AI). The commonly used anterior only approach (A) can lead to scala vestibuli insertions and osseous spiral lamina fractures.