Objectives: To report a case of congenital oval window aplasia (COWA) in a Filipino adult
presenting with unilateral maximal conductive hearing loss and discuss the diagnostic
considerations, pathophysiology and management.
Design: Case Report
Setting: Tertiary Public Referral Center
Results: Audiometric evaluation showed a maximal unilateral left conductive hearing loss. High
resolution temporal bone CT showed absence of the oval window on the left along with facial and stapes abnormalities. Exploratory tympanotomy showed an aberrant facial nerve, monopodal and abnormally located stapes and absent oval window. Postoperative hearing gain achieved after a neo-oval window and Schuknecht piston wire prosthesis remained stable over two years.
Conclusion: A congenital minor ear anomaly classified as Cremers Class 4a in which a congenital oval window aplasia was associated with an aberrant facial nerve anomaly and a monopodal stapes is reported. Recent literature supported the view that congenital oval window aplasia can in selected cases be amenable to various surgical approaches and a stable postoperative hearing gain is achievable in the long term.