Bony Fixation of the Malleus and Incus

Abstract

A material of 12 patients with bony fixations of the malleus and incus in the attic is presented. Of these patients 9 had intact, 3 interrupted ossicular chain. Various types of bony fixation of the attic were found: isolated fixation of the incus, isolated fixation of the malleus, bony fixation of the malleus as well as the incus and ossification of the ligaments. Treatment consisted in removal of the new-formed bone with mobilisation of the ossicular chain which was preserved intact. The results were good. Among the tympanoplasties in which the ossicular chain was intact, it was fixed in the attic in 10% of the cases, and among those in which the ossicular chain was interrupted in only 1.2%. In most cases the cause was chronic otitis, in one case a congenital anomaly. The aetiology and pathogenesis are discussed. It is concluded that post-infectious bony fixation presumably arises during the healing of localized osteitis. Other aetiological possibilities—such as increased pneumatization in the attic, high situation of the malleus, trauma and otosclerosis—are described and discussed.