A case of congenital bilateral stapes agenesis.

Congenital absence of the stapes and the oval window is an anomaly reported in only sporadic cases. We present a 17-year-old male patient with congenital bilateral conductive hearing loss. The external auditory canal and the tympanic membrane appeared normal on both sides. An exploratory tympanotomy in the right ear revealed dehiscence of the the horizontal segment of the facial nerve, which was displaced inferiorly, occupying the area of the absent oval window. The stapes was totally absent and a malformed long process of the incus was attached by a fibrous band to the promontory. Manipulation of the facial nerve in association with stapedectomy or vestibulotomy was avoided in order not to injure the nerve. Instead, amplification with hearing aids was recommended to the patient.