Henning Frenzel MD, PhD, Presenter: Nothing to Disclose

Gerlig Widmann, Abstract Co-Author: Nothing to Disclose

Dirk Petersen MD, Abstract Co-Author: Nothing to Disclose

Barbara Wollenberg, Abstract Co-Author: Nothing to Disclose

Christian Mohr MD, Abstract Co-Author: Nothing to Disclose

Active middle ear implants (aMEI) are being increasingly used for hearing restoration in congenital aural atresia. The existing gradings used for CT findings do not meet the requirements for these implants. Some items are expendable, whereas other important imaging factors are missing. We aimed to create a new grading system that could describe the extent of the malformation and predict the viability and challenges of implanting an aMEI as well as the hearing outcome.

103 malformed ears were evaluated using HRCT of the temporal bone. The qualitative items middle ear and mastoid pneumatization, oval window, stapes, round window, tegmen mastoideum displacement and facial nerve displacement were included. An anterior- and posterior round window corridor, oval window and stapes corridor were quantified and novelly included. They describe the size of the surgical field and the sight towards the windows. 35 ears were implanted and evaluated for hearing outcome.

The ears were graded on a 16-point scale (16-13 easy, 12-9 moderate, 8-5 difficult, 4-0 high risk). The strength of agreement between the calculated score and the performed implantations with regard to the level of difficulty of the implantation was good. The comparison of the new 16-point scale with the Jahrsdoerfer score showed that both were able to conclusively detect the high-risk group; however the new 16-point scale was able to further determine which malformed ears were favorable for aMEI, which the Jahrsdoerfer score could not do. There was no correlation between the new 16-point scale and the hearing outcome using stapes attachment. The round window attachment in difficult cases may lead to inferior results.

The Active Middle Ear Implant Score for Aural Atresia (aMEI-score) allows more precise risk stratification and decision making regarding the implantation. The use of operative corridors seems to have significantly better prognostic accuracy than the Jahrsdoerfer score. The hearing outcome does not rely on the severity of deformation, once a successful coupling of the implant is achieved. The aMEI-score represents the likelihood of achieving a successful implantation.

The Active Middle Ear Implant Score for Aural Atresia (aMEI-score) satisfies the new requirements for diagnostic imaging of congenital aural atresia with regard to active middle ear implants.

Frenzel, H, Widmann, G, Petersen, D, Wollenberg, B, Mohr, C, New Grading System for Patients with Congenital Aural Atresia Scheduled for Active Middle Ear Implants.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13020705.html