The scala vestibuli for cochlear implantation. An anatomic study.

Background: Traditionally, cochlear implantation has used the scala tympani (ST) for electrode insertion. When faced with ST ossification, the surgeon may elect to drill out the cochlea to accomplish partial electrode insertion. Theoretically, another option in this situation is to insert the electrode into the scala vestibuli (SV).

Objective: To determine whether or not the dimensions of the SV are sufficient to accommodate an electrode array so as to assess the feasibility of SV cochlear implantation.

Methods: The study of 20 normal human temporal bones, comparing the maximum diameter and surface area of the ST with those of the combined SV and scala media.

Results: The dimensions of the SV and scala media were comparable to those of the ST and appeared sufficient to accommodate a cochlear implant electrode array.

Conclusion: It appears that the combination of SV and scala media is a viable alternative route for electrode insertion, at least on the basis of anatomic dimensions, in those cases in which the ST is obliterated.