Abstract
Objective: 1) Describe computed tomography (CT), tympanogram and examination findings seen in patients with lateral external auditory canal (EAC) to mastoid fistulas. 2) Discuss treatment of patients with lateral EAC to mastoid fistulas.
Method: Retrospective chart review of patients diagnosed with lateral EAC to mastoid fistulas from January 2006 through January 2012. Data collected included computed tomography (CT) scans, audiograms, and examination and operative findings.
Results: Seventeen patients were identified. A total of 82% (n = 14) had CT scans, all of which demonstrated a fistula between the mastoid and EAC. Examination findings demonstrated 53% (n = 9) with an intact tympanic membrane, 29% (n = 5) with a perforation, and 18% (n = 3) that could not be assessed. In all, 82% (n = 14) had tympanograms, and of those, 86% (n = 12) had type B and 14% (n = 2) had type C. A total of 88% (n = 15) of patients had a history of surgery in the affected ear. Of those, 87% (n = 13) had history of canal wall-up mastoidotympanoplasty. A total of 65% (n = 11) of patients required a canal wall-down mastoidectomy.
Conclusion: External auditory canal to mastoid fistula is a potential complication of otologic surgery. This entity can sometimes be identified on examination, but CT is highly sensitive in confirming the diagnosis. Most patients require a canal wall down procedure but the canal wall can be reconstructed in select cases.
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