Osteogenesis imperfecta congenita and tarda: a temporal bone report.

The temporal bone report of an operated case of osteogenesis imperfecta tarda is presented. Histological examination confirmed the presence of bilateral fixation of the footplate by otosclerosis as the cause of the conductive hearing loss. Fragility of bony septae in the mastoid and of the stapedial crura were observed. Sensorineural impairment in later years with a reduction in neural elements in the cochlea appear related to the extent and activity of the otosclerotic foci. Additional temporal bone reports of three cases of osteogenesis imperfecta congenita show lack of deposition of the skein-like bone in the endochondral layer, sparse bony septae in marrow spaces and deficiency of the perosteal layer. The stapedial crura were thin and in two cases both were deformed and fractured.