Presentation
Left conductive hearing loss and left external auditory canal atresia. For pre-surgical planning.
Patient Data
Left ear:
microtia: grade 2 (Marx classification 1); some normal features are present but the upper ear is severely deficient.
external auditory canal atresia: complete bony and fibrous obliteration of the expected course of the external auditory canal
middle ear/tympanic cavity is adequate/normal (measured more than 3 mm in the coronal view from promontory to atretic plate); no soft tissue opacification to suggest cholesteatoma
ossicles anomalies: mild dysplastic malleus with smaller manubrium of malleus; normal incus with normal angulation of include-stapedial articulation; normal stapes seen attached at the oval window
mastoid pneumatization: hyperpneumatised-aeration beyond the mastoid where pneumatization seen at the petrous and squamous portions
facial nerve course: mastoid segment is foreshortened and anteriorly positioned; inferior bony dehisence of tympanic segment
oval and round windows: both are open and normal in diameter (more than 1mm); not stenotic or atretic
vascular anomalies: no aberrant internal carotid artery; no high riding jugular bulb
normal inner ear structures
Right ear:
-
normal except cerumen/ear wax at external auditory canal
Left microtia: grade 2 (Marx classification 1). Small rudiment soft tissue (severe malformation) "peanut ear".
Case Discussion
This patient has had left external auditory canal atresia 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 8 points (deduct facial nerve position and external ear appearance).
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