Bioactive glass-ceramics in ear surgery: animal studies and clinical results

In the search for better materials for middle ear reconstruction, ceramics have been suggested as an alternative. The bioactive glass-ceramic Ceravital was made available to us for animal experiments and clinical trials. To test its suitability in ear surgery, 101 ear operations were carried out in 53 rabbits including the reconstruction of 78 posterior auditory canal walls and the insertion of 174 middle ear implants. Parameters studied include the effects of bone paté in inducing new bone growth, the chronological course of bone apposition and remodeling, microscopic examination of mucous membrane growth on the implants and degree of lysis of the implant. In the past two and one half years some 250 ossicular prostheses have been implanted in man for reconstruction of the ossicular chain. A statistical analysis of 119 tympanoplasties after a follow-up of one and one half years shows no perforations of the tympanic membrane over the implants or rejection of the prosthesis from the middle ear. The audiological results achieved were more favorable with the use of ossicular prostheses made of bioactive glass-ceramic than those using allogenic ossicular grafts. On the basis of the histologic findings and observed clinical results, the bioactive material Ceravital is remarkably well suited for reconstruction of the posterior auditory canal wall and for implantation in direct contact with the tympanic membrane.