A new cochlear implant electrode design for preservation of residual hearing: a temporal bone study

Success in conservation of residual hearing after cochlear implantation has benefited patients with high levels of residual low frequency hearing who were not previously considered for conventional cochlear implantation. Technological developments play a key role in minimizing trauma to the cochlea during placement of electrodes.

The Nucleus Straight Research Array (SRA) has been designed and developed as a collaboration project between our centre and Cochlear Ltd with the objective of minimizing trauma to the cochlea with insertion of the electrode via the round window.

We studied 22 fresh or thawed fresh-frozen human temporal bones implanted by one otosurgeon with the SRA electrode with a standard round window technique used for cochlear implantation. An additional four temporal bones were implanted with a 'Standard' straight electrode using the same surgical technique. All insertions were performed in the scala tympani of the cochlea.

Evaluation of insertion depth and position of the electrode array inside the cochlea showed little or no evidence of significant intracochlear trauma in the vast majority of bones implanted with the SRA. Handling of the electrode carrier was reported as very satisfactory, which was evident from low resistance to insertion in the majority of cases.