Postoperative otologic evaluation of patients who have undergone ossicular reconstruction is often difficult. However, thin-section computed tomography (CT) can help determine the type of
prosthesis used for reconstruction and adequately assess for complications that may be causing postoperative
conductive hearing loss. A variety of
prostheses may be used in ossicular reconstruction (eg, stapes
prosthesis, incus interposition graft, Applebaum
prosthesis, Black oval-top
prosthesis, Richards centered
prosthesis, Goldenberg
prosthesis) and can usually be identified at CT by their shapes and locations. Several causes of prosthetic failure are readily demonstrated at CT, including recurrent
cholesteatoma and
otitis media, formation of granulation tissue or adhesions, and various mechanical problems (eg, subluxation, dislocation, extrusion, fracture, bending). Perilymphatic
fistula can be difficult to identify at CT but may be suggested by the presence of pneumolabyrinth, unexplained
middle ear effusion, or fluid accumulation within the mastoid air cells. The presence of soft tissue within the oval window niche 4-6 weeks following surgery may indicate poststapedectomy
granuloma or
fibrosis. Familiarity with the normal and abnormal CT appearances of
ossicular prostheses will enable the radiologist to assist the otologist in identifying patients in whom
revision surgery is most appropriate.