Lesions of the Middle Ear Ossicles: Acquired, Traumatic, Congenital, and Postsurgical Pathology

When interpreting temporal bone CT, middle ear ossicular pathology is the focus in 4 clinical scenarios: trauma, inflammation, congenital dysplasia, and postoperative assessment of ossicular reconstruction surgery. In the setting of trauma, ossicular dislocations are more common than ossicular fractures, and there are 5 dislocation types to consider. In the case of middle ear inflammation, ossicular motion may be mechanically restricted, as seen with tympanosclerosis, or ossicular motion may be interrupted by ossicular erosion, as seen with cholesteatoma or resorptive osteitis. In patients with congenital dysplastic lesions, the ossicles often demonstrate characteristic imaging patterns, which can be recognized on high-resolution imaging. Some typical patterns of dysplasia will be highlighted in this article. Last, postoperative evaluation of ossicular reconstruction surgery requires imaging to assess prosthesis position and identify causes of prosthesis failure. The normal imaging appearance of common ossicular prosthesis will be reviewed, followed by examples of prosthesis dislocation, which is a potential cause of surgical failure.

Learning Objectives: Identify pathology affecting the middle ear ossicles and recognize the expected postoperative appearance of the middle ear following ossicular reconstruction surgery.