Isolated congenital stapes ankylosis: an embryologic survey and literature review.

OBJECTIVE: Isolated congenital stapes ankylosis is rare but is a definite entity. Both small series and case reports have been published in various languages. The aim of this study was to review the world literature regarding isolated congenital stapes ankylosis and to critically evaluate the embryonic development of the stapes to explain the possible pathologic development of this ankylosis. DATA SOURCES: All the publications in the English, German, and French literature regarding congenital stapes anomalies were reviewed, and original research articles on the embryonic development of the stapes and related structures were extensively and critically reviewed. STUDY SELECTION: Of the many varieties of congenital stapes anomalies described in the literature, only the isolated congenital stapes fixation due to footplate or suprastructure fixations were selected in this study. DATA SYNTHESIS: After extensive and critical review of the embryonic development of the stapes, the complex and confusing embryonic development is explained in a simplified way with schematic illustrations for easy understanding. The possible theories of congenital stapes ankylosis are explained on an embryologic basis and supplemented with schematic illustrations.
CONCLUSION: Based on the development of the stapes an attempt has been made to explain the possible theories for the basis of suprastructure fixation. Theories of congenital fixation of footplate also discussed.