8.10\ Stapedectomy,

Stapedotomy, and Stapes

Prosthesis

8.10.1\ Discussion

Stapes reconstruction is performed for treatment of conductive hearing loss in patients with otosclerosis, stapes fracture, adhesions, or tympanosclerosis. Stapedectomy usually consists of resecting the entire stapes, while stapedotomy involves removing the superstructure and creating a small hole into the stapes footplate. Stapedotomy often involves minimally traumatic surgical techniques, such as hands-free laser application.

Stapes prostheses typically extend from the incus to the stapedotomy defect in the footplate and ideally do not extend medially into the vestibule more than 0.25 mm. Several types of sta-

a

b

Fig. 8.31  Schematic of a stapes piston prosthesis (a). Photographs of piston and bucket handle stapes prostheses (b) (Courtesy of Grace Medical)

pes prostheses are available, but most fall into the categories of being either a bucket or piston (Fig. 8.31). Bucket prostheses are set just under the lenticular process of the incus with a small wire that secures it, while pistons usually consist of a smaller barrel and a wire that is crimped around the long process (Figs. 8.32, 8.33 and 8.34). Alternatively, stapes prostheses can be attached to the malleus if the incus is not available for reconstruction (Fig. 8.35). Stapes prostheses can be made from a variety of materials including titanium, Teflon, fluoroplastic, and nitinol. Virtually all stapes prostheses are MRI compatible, except for the McGee stainless steel prostheses dating from 1987. Nevertheless, the metal components of the prosthesis can produce susceptibility artifact that obscures detail of surrounding structures and can resemble labyrinthitis ossificans (Fig. 8.36).

Fig. 8.32  Robinson bucket handle prosthesis. Coronal CT image shows a metallic prosthesis that extends from the long process of the incus to the oval window, where there is beam-hardening artifact

Fig. 8.33  Schuknecht Teflon wire stapes piston prosthesis. Axial CT image shows the filamentous prosthesis in position (arrow)

Fig. 8.34  Smart nitinol wire piston prosthesis. Axial CT image shows the prosthesis in position (arrow) in contact with the stapes footplate

Fig. 8.36  Susceptibility artifact from stapes prosthesis mimicking labyrinthitis ossificans. Axial CT image (a) shows a large metallic Robinson prosthesis. The corre-

sponding axial CISS image (b) shows obscuration of a portion of the cochlea due to the artifact (encircled)