Evaluation of the short hybrid electrode in human temporal bones.

HYPOTHESIS: The current hybrid electrode can be inserted without trauma to the temporal bone and, after insertion, assumes a position within the scala tympani near the outer cochlear wall just beneath the basilar membrane.

BACKGROUND: Conservation of residual hearing after cochlear implant electrode insertion requires a special insertion technique and an atraumatic short electrode. This allows electroacoustic stimulation in ears with significant residual hearing.

METHODS: Human cadaveric temporal bones were implanted with soft surgical technique under fluoroscopic observation. Dehydrated and resin-impregnated bones are dissected. Real-time electrode insertion behavior and electrode position were evaluated. The bones are examined for evidence of insertion-related trauma.

RESULTS: No gross trauma was observed in the implanted bones, and the electrode dynamics evaluation revealed smooth scala tympani insertions.

CONCLUSION: Atraumatic insertion of the 10-mm hybrid electrode can be accomplished using an appropriate cochleostomy and insertion technique.