Superior semicircular canal dehiscence and lack of the tympano-ossicular system: favourable functional aspects of a coincidental finding.

Objectives: Our objectives were to report the functional conditions of superior semicircular canal dehiscence (SSCD) associated with the post-inflammatory lack of tympano-ossicular system. Methods: A 40-year-old male, initially referred for bilateral ear discharge due to a left cholesteatoma and a right unstable 'intact bridge' tympanoplasty, underwent a left open mastoidectomy without a tympano-ossicular reconstruction. Two years later, he had a conversion of the 'intact bridge' tympanoplasty into an open mastoidectomy without reconstruction on the right side. Moreover, he had a bilateral SSCD diagnosed by means of vestibular evoked myogenic potentials (VEMPs) and high-resolution computed tomography (HRCT). Results: Combination of the absence of the tympano-ossicular system and SSCD resulted in surprisingly good hearing function. Conclusions: The reported bilateral near-to-normal hearing function outlines the possibility of a favourable outcome deriving from the association of two different adverse conditions. This presents an opportunity for reflection on the pathophysiology of sound transmission, and indicates the usefulness of including the radiological investigation of the bone overlying the superior semicircular canal even when investigating inflammatory middle ear diseases.