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:

1. normal stapes

2. open oval window

3. middle ear space

4. facial nerve position

5. malleus-incus complex

6. mastoid pneumatization

7. incus-stapes connection

8. open round window

9. 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).