[Erosion and necrosis of the long process of the incus after otosclerosis operation]

Abstract

The frequency and possible causes of erosion and necrosis of the long process of the incus induced by various types of prostheses following stapes surgery for otosclerosis are discussed. Between 1987 and 1995, 1144 stapes operations were performed including 117 revisions of stapes surgery performed by third parties and 27 revisions performed by the author. For the first time, necrosis of the long process of the incus caused by teflonplatinum piston is described on the basis of findings in five cases, in which the platinum loop had completely transmigrated the incudal process in a medial direction. By using pictures of the teflon-platinum piston and a gold piston taken by a scanning electron microscopy and a comparison between the use of a teflon-wire piston and a gold piston in two operations, an hypothesis is made that the winding grooves in the surface of the teflon shaft together with impaired middle ear mechanics were the main causes of a scar being contracted in the direction of the oval window niche with resulting necrosis of the incudal process. Requirements for an optimum stapes prosthesis are summarized as a result of the operative observations made.