Congenital aural atreasia with bilateral cochlear incomplete partition type II
Presentation
Bilateral mixed hearing loss since birth. CT scan for feasibility of cochlear implant.
Patient Data
Right ear:
microtia: grade 3 (Marx classification 1); small rudiment soft tissue (severe malformation) "peanut ear"
external auditory canal atresia: Atresia bony plate at the medial part (type B Weerda classification)
middle ear/tympanic cavity is smaller in size (measured less than 3 mm in the coronal view from promontory to atretic plate); Complete opacification of tympanic cavity may represent cholesteatoma or otitis media.
ossicles anomalies: moderate dysplastic malleus and incus; normal stapes is not well visualized at the oval window
mastoid pneumatization: absent.
facial nerve course: abnormal course where only the labyrinthine segment is seen. Tympanic and mastoid segments are not seen.
oval and round windows: oval window and round window are atretic with bony plates seen.
vascular anomalies: no aberrant internal carotid artery; no high riding jugular bulb
Inner ear: coalescence of the apical and middle turn to form a cystic apex with deficient modiolus and absence of interscalar septum. Large vestibular aqueduct.
Left ear:
microtia: grade 1 (Marx classification 1); Small but almost normal.
external auditory canal : Not stenotic or atretic.
middle ear/tympanic cavity is normal in size.
ossicles anomalies: normal
mastoid pneumatization: normal.
facial nerve course: abnormal course without the usual acute angle formed by labyrinthine and tympanic segments. However, all segments are present.
oval and round windows: oval window and round window are open
vascular anomalies: no aberrant internal carotid artery; no high riding jugular bulb
Inner ear: coalescence of the apical and middle turn to form a cystic apex with deficient modiolus and absence of interscalar septum. Large vestibular aqueduct.
Right auricle is severely malformed, "peanut ear"
Left auricle is small but identifiable anatomy.
Case Discussion
This patient has had right external auditory canal atresia (type B Weerda classification with atretic bony plate at medial part) and conductive hearing loss since birth. This HRCT temporal bone performed is for pre-surgical planning.
The Yeakley and Jahrsdoerfer 2 grading system is useful for the pre-operative HRCT temporal bone to decide the operation's outcome. This grading system is based on nine high-resolution CT scan parameters:
normal stapes
open oval window
middle ear space
facial nerve position
malleus-incus complex
mastoid pneumatization
incus-stapes connection
open round window
external ear appearance (external auditory canal)
Each parameter is assigned 1 point (if normal or mildly dysplastic), except for the stapes which was allocated 2 points. Total 10 points.
Points (5 or below) - not a surgical candidate.
8 points and above - good surgical outcome.
7 points - fair outcome.
6 points - marginal improvement.
Our patient scored 0 point for the right ear. No score needed for left ear as no left external auditory stenosis/atreasia.
Incidental findings of bilateral cochlear incomplete partition type II and bilateral vestibular aqueduct enlargement.
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