Dr Kirsty Gardner-berry1, Associate Professor Catherine Birman1, Dr Halit Sanli1, Dr WaiKong Lai1
1Sydney Cochlear Implant Centre, Gladesville, Australia
The introduction of universal newborn hearing screening has lead to a significant decrease in the age at cochlear implantation, and infants born today have an average life expectancy of over 80 years. Advances in regenerative therapies in the field of medicine have accelerated over recent years, which has resulted in the need to take into consideration the possibility of hearing impaired infants being able to have their hearing restored within their lifetime. This presentation describes the techniques currently in use to maximise preservation of residual hearing and structures during cochlear implant surgery.
There are currently four strategies in place at the Sydney Cochlear Implant Centre to optimize the opportunity to preserve residual hearing, and structures of the cochlea during cochlear implant surgery. The first strategy relates to the choice of implant array, with a preference for a thinner design. Second, is the surgical approach and angle of insertion to minimize structural damage during the drilling and insertion process. Third, is the speed of insertion, with a preference for a very slow insertion. Fourth, is the use of steroids to reduce inflammation associated with surgical entry into the cochlea, and the introduction of the implant array into the cochlear space.
Pre and post-operative pure-tone thresholds were measured on a series of adults to evaluate the success of utilizing the residual hearing and structural preservation approaches. Mixed results were obtained, with some adults demonstrating successful preservation; some initially demonstrating preservation but losing hearing over subsequent months; and some demonstrating a near total loss of hearing during the surgical period.
The mixed results in adults indicate more research is needed to better understand the factors that optimize hearing and structural preservation in cochlear implant surgery. Nevertheless, the use of soft surgery techniques should still be considered for paediatric cochlear implantation.
Kirsty is a diagnostic audiologist at the Sydney Cochlear Implant Centre, and clinical consultant audiologist at Scanmedics in the area of newborn hearing screening. Kirsty has a Bachelor of Science, Masters in Audiology, and PhD. Kirsty specializes in electrophysiological testing and early identification through newborn hearing screening.