Absent pyramidal eminence and stapedial tendon associated with congenital stapes footplate fixation: Intraoperative and radiographic findings

Abstract

ObjectiveReport an association between congenital stapes footplate fixation (CSFF) and radiological absence of the pyramidal eminence and stapedial tendon. PatientsChildren and adults with intraoperatively confirmed CSFF and an absent stapedial tendon. InterventionsComputed tomography (CT); exploratory tympanotomy with stapedotomy. Main outcome measuresAbsence of a pyramidal eminence and stapedial tendon aperture identified on preoperative CT that was confirmed intraoperatively. ResultsEight patients with intraoperative confirmation of CSFF and absent stapedial tendon were retrospectively identified. The average preoperative bone conduction and air conduction pure tone averages were 19.6 dB (SD 15.6 dB) and 55.9 dB (SD 23.6 dB), respectively. The average air-bone gap was 36.3 dB (SD 17.9 dB) preoperatively. In the seven patients who underwent preoperative CT, all were consistently identified to have an absent or hypoplastic pyramidal eminence and absent stapedial tendon aperture at the pyramidal eminence. In six cases, the stapedial footplate appeared normal, while in one case the footplate appeared abnormal which correlated with severe facial nerve prolapse observed intraoperatively. All eight cases underwent exploratory tympanotomy and demonstrated intraoperative stapes footplate fixation, absent stapedial tendon and either absent or hypoplastic pyramidal eminence, which correlated with preoperative CT findings. ConclusionsThis study identifies a clinically pragmatic association between an absent pyramidal eminence identified on high-resolution CT and the diagnosis of CSFF. In a condition that otherwise generally lacks distinctive radiological features, the absence of a pyramidal eminence on CT in a patient with nonprogressive, congenital conductive hearing loss may strengthen clinical suspicion for CSFF.