Abstract
Sixty patients with otosclerosis have been operated by two different techniques either a small fenester or a large fenester. The hearing improvement by using either a Fisch prosthesis or a House prosthesis on a vein showed significant better hearing in the high frequency area when using the Fisch prosthesis. Beside the better hearing in the high frequency area the Fisch prosthesis are recommended in technical difficult cases where extraction of the footplate can be difficult or impossible.