Relations between cochlear histopathology and hearing loss in experimental cochlear implantation

► The extent of the tissue response to implantation was correlated with other markers of cochlear injury and inflammation. ► Hearing one week after surgery correlated with the presence of osseous spiral lamina fracture. ► The extent of the tissue response limited the best hearing observed one month after cochlear implantation. ► Worse hearing at one month correlated with more extensive tissue response, poorer outer hair cell counts and OSL injury. ► Progressive hearing loss, seen in 19% of animals, was correlated with the extent of the tissue response.