To determine the prevalence of ankylosis
at the posterior stapediovestibular joint
(SVJ) in temporal bones with otosclerosis
, with special reference to stapes surgery.
Long-term success of the laser stapedotomy minus prosthesis (STAMP) procedure, anterior crurotomy, and similar partial stapedectomy procedures depends on lack of ankylosis
and lack of otosclerosis
involving the posterior SVJ. Previous work has shown that the air-bone gap in otosclerosis
correlates with narrowing and loss of the SVJ space. However, the prevalence and histologic features of otoscle-rotic involvement of the posterior SVJ space have not been well characterized.
Histologic assessment of serial sections through the oval window niche in 140 temporal bones with otosclerosis
that had been sectioned in the axial plane (age range 20–95 years, mean 68). Bones with stapes mobilization or stapedectomy were excluded.
Results and Conclusions
Two of 140 bones had otosclerosis
exclusively at the posterior SVJ. Of the remaining 138 bones, all of which had otosclerosis
at the anterior SVJ, 82 bones also had otosclerosis
at the posterior joint. Of the 56 bones without otosclerosis
of the posterior joint, there was bony ankylosis
of the posterior joint in 3 bones. Thus, 53 bones (38%) had neither ankylosis
involving the posterior joint, and they would be potentially suitable for a laser STAMP or a similar procedure. There was no correlation between otosclerosis
at the posterior SVJ and age, sex, or duration of conductive hearing loss. Otosclerosis
at the posterior joint in one ear was significantly associated with its presence at the posterior joint in the opposite ear (p = 0.01). The audiogram could not be used to reliably predict otosclerotic involvement of the posterior SVJ or the degree of footplate pathologic changes, such as ankylosis