Congenital Oval Window Aplasia: An Unusual Cause of Conductive Hearing Loss in an Adult

• Main Authors: Charlotte M. Chiong, Rachel T. Mercado-Evasco, Alessandra E. Chiong, Mary Ellen C. Perez, Franco Louie L. Abes, Abner L. Chan
• Format: Article
• Language: English
• Published: Philippine Society of Otolaryngology-Head and Neck Surgery, Inc. 2016-06-01
• Series: Philippine Journal of Otolaryngology Head and Neck Surgery
• Subjects: : oval window absence, Cremers classification, congenital middle ear
• Online Access: https://pjohns.pso-hns.org/index.php/pjohns/article/view/315
• ISSN: 1908-4889; 2094-1501

Objective: 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. Methods:             Study Design:  Case report             Subjects: One (1)             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. Keywords: oval window absence,  Cremers classification, congenital middle ear