The anterior and superior malleal ligaments in otosclerosis: a histopathologic observation.

HYPOTHESIS

The aim of this study was to assess, in otosclerosis, whether the anterior and superior malleal ligaments show histologic changes that can lead to reduced malleal mobility and eventual fixation, and also to evaluate whether these changes are related to the degree of histologic otosclerosis.

BACKGROUND

Fixation of the malleus seems to be one of the most controversial clinical entities in the acquired condition of otosclerosis. It has even been postulated that persistent conductive deafness, or progression of conductive deafness after initial improvement after stapedotomy, could be due to unsuspected malleus fixation.

METHODS

Fifty eight temporal bones with known otosclerosis and 43 normal temporal bones were selected. In addition, 10 temporal bones of fetuses and children were also studied. Otosclerosis of the footplate and otic capsule was graded as none, mild, moderate, and severe. The histologic changes in the ligaments also were graded from none to severe.

RESULTS

The median ages of patients in the otosclerotic and normal groups were 62 and 60 years, respectively. In the anterior malleal ligament of the otosclerotic bones, 10% mild (+), 60% moderate (++), and 30% severe (+++) degrees of hyalinization were observed. In the anterior malleal ligament of the nonotosclerotic bones, 14% showed no hyalinization, 24% had only a tinge of hyalinization (minimal), 51% had mild (+) hyalinization, and 11% had moderate (++) hyalinization. Superior ligament hyalinization appears to be related to the severity of anterior ligament hyalinization. The severity of otosclerosis in the footplate or the otic capsule did not appear to be related to the severity of hyalinization.

CONCLUSION

From this study, it is apparent that otosclerotic bones have a significantly high incidence of hyalinization of the anterior malleal ligament. This seems to be related to the duration rather than the severity of otosclerosis. It is important to properly evaluate malleal mobility during all stapes surgery.