EROSION AND NECROSIS OF THE LONG PROCESS OF THE INCUS FOLLOWING OTOSCLEROSIS SURGERY

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 stape s 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 teflon-platinum piston is described on the basis of finding s in five cases, in which the platinum loop had completely transmigrat ed 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 a nd a gold piston in two operations, an hypothesis is made that the win ding 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 t he incudal process. Requirements for an optimum stapes prosthesis are summarized as a result of the operative observations made.