large vestibular aqueduct syndrome

Enlarged vestibular aqueduct syndrome
EESS
EEDS
LVAS
EVAS
Enlarged endolymphatic sac syndrome
Enlarged endolymphatic duct syndrome
large vestibular aqueduct syndrome
enlarged vestibular aqueduct
enlarged endolymphatic sac syndrome (EESS)
enlarged endolymphatic duct syndrome (EEDS)
Large vestibular aquaduct syndrome (LVAS)
Large endolymphatic sac anomaly (LESA)
erweiterter vestibulärer Aquäduct
dilated vestibular aqueduct
Large vestibular aquaeduct syndrome
Large vestibular aqueduct syndrome (LVAS), also known as enlarged vestibular aqueduct (EVA) or large endolymphatic sac anomaly (LESA), refers to the presence of congenital sensorineural hearing loss with an enlarged vestibular aqueduct due to enlargement of the endolymphatic duct. It is thought to be one of the most common congenital causes of sensorineural hearing loss.
Clinical presentation
Sensorineural hearing loss starts in childhood and is progressive . Hearing loss may be sudden onset and occurs after minor head trauma .
Pathology
Associations
Associated anomalies are the norm, occurring in ~85% of patients :
- Pendred syndrome
- vestibular anomalies
- cochlear anomalies (e.g. cochlear hypoplasia, Mondini malformation, etc.)
- semicircular canal anomalies
Radiographic features
CT/MRI
A measurement of the vestibular aqueduct of 1.5 mm is considered the upper limit of normal . This measurement is ideally made halfway between the crus and the aperture on an axial view (i.e. AP dimension). Some studies suggest consideration of upper limit measurements of the midpoint of the aqueduct and operculum being at 1 mm and 2 mm, respectively .
The bony modiolus is not visible in up to 90% of cases.