Head and Neck ImagingPerilymphatic fistula
abnormal communication between the perilymphatic space in the
inner ear, and the
middle ear. The fistula occurs at the level of the oval window (more common) or round window. When
congenital, such a fistula may be associated with various inner ear malformations. They may also occur spontaneously, or be post-traumatic (barotrauma, after
stapedectomy, after sudden physical strain) or secondary to infection or
neoplasm. The symptoms are fluctuating
sensorineural hearing loss and
vertigo. Imaging is mainly performed to exclude other pathology which may be associated with such symptoms. Perilymphatic fistula itself may present on
CT as pneumolabyrinth (air bubble in part of inner ear) and/or subtle middle ear fluid effusion. Abnormalities of the oval window and stapedial superstructure have been described in this context.
RH