Ossicular Chain Transplantation in Cats

Abstract

Seventy-one ossicular chains were transplanted in cats to determine the fate of the transplanted ossicles which were placed in 70% alcohol for two months prior to surgery. The morphology, bone repair and viability of the ossicles were determined by gross appearance, microscopic examination, serial sections of four decalcified temporal bones and tetracycline labels followed by fluorescent microscopy. There was extreme reaction in the middle ear to the transplanted ossicles with extensive fibrosis but the shape of the ossicles was not altered even after 19 months. However, the stapes could not be grossly identified in nine ears. The endochondral bone was gradually replaced by cortical bone with the greatest activity within the period of 3 to 6 months postsurgery and cessation of the activity after 13 to 15 months. This process of transition was studied with tetracycline labels and periodic microscopic sections of the ossicles. The inner ear reacted in different ways ranging from complete degeneration of the organ of Corti, to cochlear hydrops, to new bone formation and degeneration of the stria vascularis.