[Stapedo-vestibular ankylosis associated with osteopathy of the promontory (author's transl)].

The authors present two unusual operative findings during surgery for stapedo-vestibular ankylosis, of which no similar cases would appear to be found in the literature. The first case posed the problem of stapedo-vestibular ankylosis as a sequel of clinically latent otitis, the only manifestations of which were radiological opacity of the mastoid and an area of osteitis of the promontory, still active, in the absence of any other progressive inflammatory phenomena or sequelae. Surgery required curettage and opening of the promontory, associated with total stapedectomy and a Teflon-inter-position. The functional result was very good. The second case of typical bilateral stapedo-vestibular ankylosis suggested the possibility of "malignant" otospongiosis, or at all events, markedly progressive. Surgery led to opening of the labyrinth. After platinectomy and excision of a bony sequestrum, there remained only a large fossa with an area equivalent to 3 times that of a usual fenestra ovale. A Teflon-interposition piston was performed with a good result. These rare forms lead to discussion of:--Lobstein's disease, Paget's disease and parathyroid osteosis. Finally, the authors approach the problem of the therapeutic attitude to be adopted in the presence of such rare conditions.