Cochlear‐facial dehiscence—A newly described entity

Abstract

Dehiscence of the cochlear otic capsule has recently been described as a pathologic entity. We describe two cases of cochlear-facial dehiscence, which are the first reported: a 69-year-old male who complained of hearing loss, autophony, and pulsatile tinnitus and a 41-year-old female who complained of left-sided hearing loss, pulsatile tinnitus, and vertigo. In both, computed tomography (CT) showed bony dehiscence between the facial nerve and cochlea. Cochlear-facial dehiscence is another example of otic capsule dehiscence that produces symptoms of third-window lesions. When patients present with symptoms of third-window lesions and CT does not show superior canal dehiscence, cochlear-facial dehiscence should be considered.

Superior Canal Dehiscence Syndrome: Lessons from the First 20 Years

“…Aside from dehiscence of the superior semicircular canal, several other sources of labyrinthine dehiscence can lead to symptoms similar to those in SCDS, including that of the posterior semicircular canal (52, 53), lateral semicircular canal (17, 54), vestibular aqueduct (55), facial nerve (56), internal auditory canal (57), and the carotid canal (58, 59). Merchant and Rosowski synthesized many of these reports and broadly proposed that any dehiscence of the inner ear can lead to an inner ear conductive hearing loss from a third mobile window (60).…”

Prevalence of Cochlear-Facial Dehiscence in a Study of 1,020 Temporal Bone Specimens

“…We recently described the unique entity of cochlearfacial dehiscence (CFD) (3). Dehiscence between the basal turn of the cochlea and the labyrinthine segment of the facial canal manifested in two patients as hearing loss, autophony, and/or pulsatile tinnitus.…”

Cochlear-Internal Canal and Cochlear-Facial Dehiscence: A Novel Entity

“…As in other reported cases of otic capsule dehiscence, VEMPs were preserved [7] . Although VEMPs are highly sensitive and specific for SSCD [10] , the negative finding in this scenario may be attributed to the small size of the dehiscence [2] . Unfortunately, we do not know for certain the exact role that this entity plays in the present case; could this dehiscence be the cause of the refractive treatment in this particular case of bilateral Meniere's disease?…”

“…An otic capsule dehiscence opens up a third window into the inner ear, and clinical findings such as a low-frequency bone conduction hearing loss, dizziness, vertigo, or Tullio phenomenon have been reported [2,7] . When presuming an otic capsule dehiscence, it is important to consider other conditions that might resemble or mimic a third window syndrome, as is the case of vestibular aqueduct enlargement or perilymphatic fistula.…”

“…Since the first report of otic capsule dehiscence in patients with superior semicircular canal dehiscence (SSCD) by Minor in 1998 [1] , different types of otic capsule dehiscence restricted to the cochlea have been described: cochlear-carotid, cochlear-internal auditory canal, or cochlear-facial dehiscence [2] . The awareness of this phenomenon is important considering that a dehiscence in the otic capsule opens up a third window.…”