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The course of the facial nerve in evaluation of Congenital aural atresia repair candidacy
Author(s) -
Haas P.,
Choo D.
Publication year - 2010
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1002/lary.21262
Subject(s) - candidacy , medicine , citation , general surgery , library science , computer science , political science , law , politics
Background & Significance Surgical repair of congenital aural atresia (CAA) is controversial due to variable longterm hearing out comes and the risk of facial nerve damage. However, good hearing results can be obtained with minimal risk in the hands of an experienced surgeon if appropriate patient selection and preoperative evaluation are employed. The Jahrsdoerfer grading scale is the current standard by which most otologic surgeons determine fitness for surgical repair of CAA. The Jahrsdoerfer grading scale is based on the relative normalcy of 9 anatomic structures in the atretic ear based on high resolutions CT scan. One point is awarded for a relatively normal oval window, middle ear space, facial nerve , maleus-incus complex, mastoid pneumatization, incus-stapes connection, round window, and external ear with a present stapes receiving 2 points for a possible total of 10 points.1, 2 Although the Jahrsdoerfer grading system has been validated independently 1,3 Shonka et al suggested that it may be unnecessarily complex. Shonka et all found that middle ear space is the only single component of the Jahrsdoerfer scale that is a statistically significant predictor hearing outcome, though facial nerve score approached statistical significance (p<0.08). 3 The course of the facial nerve may be important in predicting hearing outcomes by determining the feasibility of surgery. A larger space makes drilling a wider canal easier and safer and having a wider canal likely prevents complications (such as restenosis or recurrent conductive hearing loss). This is important since postoperative complications have been cited as major hurdles to a successful surgery. TM lateralization is one common problem, but the single most commonly cited post-operative complication is canal re-stenosis 4,5. To prevent this, a wider than physiologic canal is recommended. Placement of this canal is restricted by the dura superiorly, the glenoid fossa anteriorly, and the facial nerve posteriorly. The facial nerve may also block access to the oval window, preventing osicular chain reconstruction/manipulation. For these reasons, among others, the path of the facial nerve may influence surgical outcome and fitness for surgery.