Prospective Randomized Controlled Double-blinded Study Comparing Cochlear Implantation Through a Round Window Versus Cochleostomy Approach
In 1985, the United States Food and Drug Administration (FDA) approved multichannel cochlear implants (CIs) for adults with profound hearing loss; and in 1990, implantation was approved for children. Since then, this procedure has become the standard of care for patients with severe-to-profound sensorineural hearing loss. Successful outcomes are dependent not only on extrinsic factors, but also on intrinsic factors that cannot always be modified by the CI team. Significant predictive factors for hearing outcomes in patients with CIs have been previously reported. These include, but are not limited to, duration of deafness, level of preimplant speech recognition, pre/postlingual status, and the coupling of device electrodes. Recipient age does not appear to have a significant impact on hearing outcomes in elderly candidates.
Earlier studies have found that, because of its dimensions and proximity to the spiral ganglion cells, the scala tympani (ST) is the preferred location for CI electrode placement. A number of recent studies have proposed that intraoperative factors may be important determinants of electrode location and possibly of audiological outcome. Preliminary reports suggest that intracochlear electrode position- specifically, placement within the ST-is associated with improved audiological outcomes. Additionally, different surgical techniques have been proposed to minimize trauma during electrode insertion and to increase the likelihood of placement within the ST - namely round window and anteroinferior cochleostomy electrode insertion.
Currently, the best surgical approach for electrode insertion is highly debated, fueled by a lack of strong evidence to support one method over another. While a number of CI centers have begun to utilize a round window approach, many large volume centers in the United States and world wide continue to routinely employ cochleostomy electrode insertions. With an increasing number of patients being implanted with greater degrees of residual hearing, such data will become critical towards reducing intracochlear injury and optimizing patient outcomes. To the investigators' knowledge, no clinical study has prospectively investigated the relationship between surgical insertion technique, intracochlear electrode location, and postoperative hearing outcomes. To this end, the investigators are initiating a multicenter prospective randomized controlled double-blinded study comparing round window and cochleostomy cochlear implant electrode insertion.