[Ear ossicle transplants for reconstruction of sound transmission in the middle ear. A histologic long-term study].

In this study 130 ossicular middle ear transplants were studied. 33 remained in the middle ear for 10 years or longer, one for 21 years. The majority of the grafts show 5% to 40% bone new formation. Absence of vital bone or subtotal host bone replacement is exceptional. The amount of bone new formation appears independent the implantation time. 75% of the grafts show no bone resorption. In 15% sound transmitting might be impaired due to resorption. Grafts with a high degree of bone new formation show less resorption. 21% of the ossicles have signs of inflammation. Inflammation boosts bone turnover with resorption on one hand and new for resorption. Cholesteatoma is the main cause of resorption and inflammation. The critical phase for resorption of the graft are the first two to three years after transplantation. No considerable difference was found between autografts and allografts (homografts). Histological and metabolical properties of the ossicles seem to be responsible for the stability of the graft. Ossicular grafts have a good longterm stability which makes them very suitable for reconstruction of the ossicular chain.