Introduction
With expanding indications and relaxation of candidacy criteria, a growing number of today’s cochlear implant (CI) candidates present to the clinic with significant amounts of residual hearing in the low frequencies. Preservation of residual hearing leads to better post-operative outcomes, offers the possibility to stimulate electro-acoustically, and safeguards against future revision surgeries and treatment options. This challenges CI manufacturers to develop atraumatic electrode arrays and surgeons to insert them in ways that minimize the loss of hearing.
Material and Methods
220 patients were included in this retrospective data analysis, who have been implanted with the HiFocus SlimJ lateral wall electrode array from Advanced Bionics since the end of 2017. The majority of insertions were supported by ECochG monitoring through a research system or the AIM tablet, where inner ear responses to acoustic stimulation are recorded with the most apical electrode contact in order to provide real-time insights on cochlear health during surgery. The electrode insertion was modified based on the amplitude if necessary. Audiometric thresholds and speech intelligibility test results were collected pre-operatively and on routine appointments post-operatively. Additionally, the electrode position was reconstructed based on pre-operative MRI and post-operative CT data, with a view to investigate which parameters influence hearing preservation significantly (e.g. ECochG monitoring, age, insertion depth).
Results
For 171 patients, a pre-operative audiogram was available (median LF PTA was 75 dB). The average post-operative hearing loss was 9 dB after three months, 17 dB after one year and 28 dB after two years. The analysis of influential parameters is ongoing and will be presented at the conference.
Conclusion
To drive the future development of atraumatic electrode arrays and structure preserving insertion techniques, a good understanding of the important factors influencing hearing preservation is essential. The results of this analysis will bring valuable insights and provide a good foundation for future improvements in insertion planning and quality control analyses.

Introduction
**With expanding indications and relaxation of candidacy criteria, a growing number of today’s cochlear implant (CI) candidates present to the clinic with significant amounts of residual hearing in the low frequencies. Preservation of residual hearing leads to better post-operative outcomes, offers the possibility to stimulate electro-acoustically, and safeguards against future revision surgeries and treatment options. This challenges CI manufacturers to develop atraumatic electrode arrays and surgeons to insert them in ways that minimize the loss of hearing.**
**Material and Methods**
**220 patients were included in this retrospective data analysis, who have been implanted with the HiFocus SlimJ lateral wall electrode array from Advanced Bionics since the end of 2017. The majority of insertions were supported by ECochG monitoring through a research system or the AIM tablet, where inner ear responses to acoustic stimulation are recorded with the most apical electrode contact in order to provide real-time insights on cochlear health during surgery. The electrode insertion was modified based on the amplitude if necessary. Audiometric thresholds and speech intelligibility test results were collected pre-operatively and on routine appointments post-operatively. Additionally, the electrode position was reconstructed based on pre-operative MRI and post-operative CT data, with a view to investigate which parameters influence hearing preservation significantly (e.g. ECochG monitoring, age, insertion depth).**
Results
**For 171 patients, a pre-operative audiogram was available (median LF PTA was 75 dB). The average post-operative hearing loss was 9 dB after three months, 17 dB after one year and 28 dB after two years. The analysis of influential parameters is ongoing and will be presented at the conference.**
Conclusion
To drive the future development of atraumatic electrode arrays and structure preserving insertion techniques, a good understanding of the important factors influencing hearing preservation is essential. The results of this analysis will bring valuable insights and provide a good foundation for future improvements in insertion planning and quality control analyses.

Long-term Hearing Preservation with the SlimJ Electrode Array

It is with great pleasure and enthusiasm, that on behalf of the Cochlear Implant centers of the Radboud UMC in Nijmegen and Erasmus MC Sophia Children’s Hospital in Rotterdam to invite you to attend the 16th European Symposium on Pediatric Cochlear Implantation to Rotterdam, the Netherlands in 2023.

Yours sincerely, on behalf of the CI Centers at Radboud UMC and Erasmus MC,