Inner ear cholesteatoma and the preservation of cochlear function. Labyrinthine destruction by direct cholesteatoma invasion has always been considered a serious threat to the inner ear function. A number of reports in the literature have cited both patients who had preservation of hearing despite widespread erosion of the labyrinth by cholesteatoma and patients who had retained auditory function despite surgical removal of the matrix from the labyrinth. In most cases the vestibular portion of the inner ear was invaded but cases of cochlear involvement have been described as well. Twelve cases with pre-operative auditory function preservation despite extensive labyrinthine destruction treated at our Institution are reported. Seven cases retained cochlear function post-operatively. Possible explanations of this occurrence and implications of related with hearing preservation in the presence of widespread inner ear destruction by chronic inflammatory disease are discussed. 