Use of a mid-scala and a lateral wall electrode in children: insertion depth and hearing preservation

Abstract

Conclusions: Atraumatic insertion of the HiFocus^TM Mid-Scala (HFMS) electrode via the round window was successfully achieved in seven children. Residual hearing 6 months post-operatively was preserved to within 10 dB HL of the pre-operative audiogram at 500 Hz for six children, indicating minimal initial insertion trauma to the cochlea.

Objectives: The objectives were to document the clinical experience and evaluate differences between HFMS and HiFocus^TM 1j (HF1j) by means of insertion depth and hearing preservation results.

Method: Nineteen children were prospectively recruited and consecutively implanted with the HF1j electrode (n = 12) or the HFMS electrode (n = 7) via the round window. Average median angular insertion depths and the amount of residual hearing preserved at 6 months post-operatively were compared between the two electrode groups.

Results: The median angular insertion depth for the HF1j was 439° and for the HFMS 435°. Preservation of residual hearing at 500 Hz was assessed in seven HFMS subjects and 11 HF1j subjects. Based on the Skarzynski formula, three out of seven subjects (42%) in the HFMS group had their residual hearing completely preserved at 500 Hz. In the control group, no subjects had complete hearing preservation and five subjects had a complete loss of residual hearing.

Keywords:

• Cochlear implant
• electrode
• hearing preservation
• insertion depth
• insertion trauma
• mid scala
• residual hearing

Disclosure statement

The study was sponsored by Advanced Bionics. Co-author DG is an employee of Advanced Bionics. The authors report no other conflict of interest. The authors alone are responsible for the content and writing of the paper.