Congenital absence of the oval window: radiologic diagnosis and associated anomalies.

Abstract

Congenital absence of the oval window can be diagnosed on CT studies. In the present series, this anomaly was associated with a grossly aberrant horizontal facial nerve canal in six of nine involved ears. Familiarity with the developmental sequence of oval window formation fosters an understanding of these anomalies. Preoperative recognition is important clinically, as a low facial nerve will block surgical access to the oval window and its presence will alter patient management.