After initially successful preservation of residual hearing with cochlear implantation, some @entity1 experience subsequent delayed @entity393 . The etiology of such delayed @entity393 is unknown. @entity1 temporal bone pathology is critically important in investigating the etiology, and directing future efforts to maximize long term hearing preservation in cochlear implant @entity1 . Here we present the temporal bone pathology from a @entity1 implanted during life with an Iowa/Nucleus Hybrid S8 implant, with initially preserved residual hearing and subsequent @entity393 . Both temporal bones were removed for histologic processing and evaluated. Complete clinical and audiologic records were available. He had bilateral symmetric high frequency severe to profound @entity393 prior to implantation. Since he was implanted unilaterally, the unimplanted ear was presumed to be representative of the pre-implantation pathology related to his @entity393 . The implanted and contralateral unimplanted temporal bones both showed complete degeneration of inner hair cells and outer hair cells in the basal half of the cochleae, and only mild patchy loss of inner hair cells and outer hair cells in the apical half. The total spiral ganglion neuron counts were similar in both ears: 15,138 (56% of normal for age) in the unimplanted right ear and 13,722 (51% of normal for age) in the implanted left ear. In the basal turn of the implanted left cochlea, loose fibrous tissue and new bone formation filled the scala tympani, and part of the scala vestibuli. Delayed loss of initially preserved hearing after cochlear implantation was not explained by additional post-implantation degeneration of hair cells or spiral ganglion neurons in this @entity1 . Decreased compliance at the round window and increased damping in the scala tympani due to intracochlear @entity82 and new bone formation might explain part of the post-implantation @entity393 . Reduction of the inflammatory and immune response to cochlear implantation may lead to better long term hearing preservation post-implantation.

Delayed loss of hearing after hearing preservation cochlear implantation: XXXX temporal bone pathology and implications for etiology.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient', 'Human'] @entity393 :: ('MESH:D034381', 'Disease') :: ['hearing loss'] @entity82 :: ('MESH:D005355', 'Disease') :: ['fibrosis']
@entity1 :: (9606,Species) :: ['Human']
